Dr Brian Hanley

The aim of this study was to provide a fully comprehensive laboratory-based analysis of overground elite race walking biomechanics, and evaluate differences between race walking, normal walking and running, between race walking speeds, between athlete performance standards and between sexes using advanced biomechanical data collection techniques and progressive statistical analysis methods. Forty-five international race walkers of 16 different nationalities volunteered to participate in this cross-sectional design study. The sample of athletes included two IAAF World Championship medallists, a European Champion, a European Championship silver medallist, a World U20 (junior) Champion, a Commonwealth Games silver medallist, and 18 other athletes who had competed at the Olympic Games (or had the qualifying time), IAAF World Championships, World U20 Championships or World University Games. A bespoke 72-marker marker set was used to measure whole-body kinematics. The optoelectronic system was synchronised with surface electromyography data to measure muscle activity of the upper body. The experimental trials consisted of; normal walking, race walking at 10 km PB pace, running at race walking 10 km PB best, race walking at 20 km PB pace, and race walking at training pace. Statistical parametric mapping was used to consider whole-body kinematic differences throughout the gait cycle. The pectoralis major and middle deltoid muscles separated race walking from the other gait types and was found to be important with changes in race walking speed and standard of race walker. Rectus abdominis was also found to be of importance for race walking. Sagittal plane shoulder and elbow kinematics and frontal plane thorax motion was also found to change with faster race walking speed and standard of race walker. The studies also found that race walking is a unique gait that is neither closer to normal walking nor running. This is predominantly because the knee motion is restricted by World Athletics Rule 54.2, and athletes must compensate for the lack of knee flexion during stance, which normally is one of the six determinants of walking gait, and a feature of passive shock absorption in running. Knee kinematics did not change between speeds, sex and standards. This study was the first to measure upper body muscle activation and whole body 3D kinematic data analysis of elite race walkers that considers differences between gait forms using a repeated measures design on world-class race walkers. Furthermore, the statistical approach is novel to the analysis of race walking kinematics. This information offers a much needed original contribution to the body of work conducted to date on race walking biomechanics, which could positively impact coaches and athletes in enhancing performance.

The purpose of this study was to analyse and compare pacing profiles of senior men and women competing in the 2017 World Cross Country Championships. Finishing and split times were collated for 118 men and 81 women competing over the newly introduced race distance of 10 km (five laps of approximately 2 km). Athletes were grouped according to finishing time, and changes in pace measured using lap times, except between Laps 1 and 2 because of a shorter first lap (times relative to the winner were used instead). Within both men’s and women’s races, groups slowed during the early stages, but then either sped up or maintained pace during the last lap. There were few differences between groups with regard to overall pacing profiles, or between sexes. The men’s fast finish contrasted with slower finishes found in previous editions (over 12 km), and the degree to which women were slower than men (approximately 12%) was very similar to track racing and showed the decision to equalise the distances run by both sexes was sound. As in other distance events, athletes are recommended to try to achieve an even pace throughout, an approach that proved beneficial to both gold medallists.

The purpose of this study was to measure the effects of fatigue on gait parameters during running. Research has shown that changes due to fatigue include those of step length, cadence, flight time, and joint angles. Thirteen male distance runners ran 10000 m at a pace equivalent to 103% of their personal best time. Kinetic data was collected using a Gaitway treadmill (1000 Hz), and kinematic data using two RedLake MotionPro high-speed cameras (250 Hz). Data was collected at five points. Repeated measures ANOVA showed that there were significant differences in maximum force, impulse, and contact time (p < .01). Dependent t-tests showed a significant difference for the knee angle at take-off (p < .01). The kinetic and temporal changes occurred as early as 3000 m. Athletes are recommended to race at a constant pace to reduce the effects of fatigue.

Racewalking is an Olympic event requiring great endurance, and racewalkers often use treadmills in training because of the benefits of having a flat, unchanging surface where pace judgment can be learned, and because inclement weather can be avoided. The effects of fatigue associated with racewalking on a treadmill have not been studied, and could be informative with regard to the maintenance of legal technique. The aim of this study was to measure key gait variables during a physically demanding treadmill racewalk. Fourteen international racewalkers completed 10 km on an instrumented treadmill at a pace equivalent to 103% of their recent best time. Spatiotemporal and ground reaction force data were recorded at four distances. High-speed videography data were simultaneously recorded to analyze changes in knee angle between the early and late stages. Increases in step length and corresponding decreases in cadence were found, although the small changes were not considered meaningful. There was also a small increase in flight time and a small decrease in push-off force. There were no other significant changes for any other variables (including knee angles). The increase in flight time might be important given that racewalkers are not permitted a visible loss of contact and suggests that fatiguing sessions on a treadmill can lead to the adoption of non-legal technique. However, this disadvantage of treadmill training can be negated if the coach scrutinizes the athlete throughout the session, and overall the consistent technique used is of benefit with regard to learning correct form and pacing ability.

The European U23 Championships are an important competition showcasing young athletic talent. The expansion of competition in this age group provides a clear and contemporary rationale for studying these championships. Since its inception in 1997, this biennial competition has been used as a major milestone in the athlete’s progress to world class competition. In this study, athletes competing from 1999 to 2013 in sprints, middle distance and steeplechase, long distance and race walks, hurdles and combined events, jumps and throws were observed. Their Global Wait (time taken between U23s and global championships) and Final Wait (transition time between U23s and reaching a final at global championships) along with successes were the criteria used for assessment. Interesting trends materialised regarding what events athletes continued to compete in or transitioned from (e.g. comparing throwers with combined events), and the time it took before competing at a global final (e.g. 800m women waited the longest). The measured success rate (finals and medal positions) of the U23 athletes within this study attests to the importance of these championships to athlete development.

The purpose of this study was to investigate the effects of fatigue on kinematic parameters during a 5 km road race, and to establish how men and women fatigue differently. 17 highly competitive distance runners (9 male, 8 female) were videoed (50 Hz) as they completed the English National 5 km championships. Three-dimensional kinematic data were analysed using motion analysis software (SIMI, Munich). Data were recorded at 950 m, 2,400 m, and 3,850 m. Repeated measures ANOVA showed a significant decrease in speed (p < 0.01) which occurred due to both decreased step length and cadence (p < 0.05). Differences in speed, step length and contact time between men and women were found (p < 0.05). Athletes can reduce the risk of fatigue by using appropriate racing tactics.

The aim of this study was to describe the pacing profiles and packing behaviour of athletes competing in the IAAF World Half Marathon Championships. Finishing and split times were collated for 491 men and 347 women across six championships. The mean speeds for each intermediate 5 km and end 1.1 km segments were calculated, and athletes grouped according to finishing time. The best men and women largely maintained their split speeds between 5 km and 15 km, whereas slower athletes had decreased speeds from 5 km onwards. Athletes were also classified by the type of packing behaviour in which they engaged. Those who ran in packs throughout the race had smaller decreases in pace than those who did not, or who managed to do so only to 5 km. While some athletes’ reduced speeds from 15 to 20 km might have been caused by fatigue, it was also possibly a tactic to aid a fast finish that was particularly beneficial to medallists. Those athletes who ran with the same competitors throughout sped up most during the finish. Athletes are advised to identify rivals likely to have similar abilities and ambitions and run with them as part of their pre-race strategy.

Race walking is an endurance event with technical rules that make it an abnormal form of gait. The purpose of this retrospective study was to survey training habits and injury prevalence amongst international race walkers. Self-administered questionnaires were provided in English, French, German, Russian and Spanish to race walkers at various international competitions and via email. The questionnaire was designed to record the athletes’ competitive performances, typical training practices, and injury locations and occurrences. Questionnaires were completed by 112 race walkers from 28 nations. On average, men covered 125km of race walking across nine weekly training sessions, while women covered 84km across seven sessions. Aside from these specific race walking sessions, most athletes also took part in running (80%) and resistance training (64%). The most commonly used training surfaces were roads (98%) and athletics tracks (68%). Injuries to the hamstrings, knees, feet and shins were the most frequently reported and in more than half of cases required medical treatment and / or time off training. In conclusion, race walking requires a great volume of training and there is a consequential risk of overuse injuries. It is possible that, as shown by other research, the frequent injuries to the hamstrings and shins are partly a result of the technique used.

The aim of this study was to describe pacing profiles and packing behaviours of athletes in Olympic and World Championship marathons. Finishing and split times were collated for 673 men and 549 women across nine competitions. Mean speeds for each intermediate 5 km and end 2.2 km segments were calculated. Medallists of both sexes maintained even-paced running from 10 km onwards whereas slower finishers dropped off the lead pack at approximately half-distance. Athletes who ran with the same opponents throughout slowed the least in the second half (P < .001, men: ES ≥ 1.19; women: ES ≥ 1.06), whereas other strategies such as moving between packs or running alone were less successful. Overall, women slowed less (P < .001, ES = 0.44) and were more likely to run a negative split (P < .001), and their more conservative start meant fewer women dropped out (P < .001). This also meant that women medallists sped up in the final 2.2 km, which might have decided the medal positions. Marathon runners are advised to identify rivals with similar abilities and ambitions to run alongside provided they start conservatively. Coaches should note important sex-based differences in tactics adopted and design training programmes accordingly.

Brian Hanley looks at the implications of a study into pacing at the World Cross Country Championships

The aim of this study was to analyze swing characteristics during race walking and to compare these with distance running. The rules of race walking demand that no visible flight time should occur and the stance leg must be straightened from initial contact to midstance. Previous research has not examined whether these rules also have an effect on swing and what consequences might arise. Ten male race walkers and ten male distance runners walked or ran respectively on an instrumented treadmill for 10 km with two in-dwelling force plates. Trials lasted 30 seconds and simultaneous 2D video data were recorded and digitized at 125 Hz. The moment of inertia of the thigh, shank, foot and whole lower limb was calculated using the parallel axis theorem. The distance runners were faster with longer strides, although cadence was not different. The race walkers had shorter swing times, longer contact times, and smaller maximum knee flexion angles (100° ± 6) than the distance runners (56° ± 6). The smaller knee flexion angles in race walkers meant they experienced greater swing leg moment of inertia than the distance runners but there were few associations in either group between knee flexion angle or moment of inertia with key performance parameters. Swing phase kinematics in race walking are restricted by the rules of the event and result in knee angular motions different from those in distance running, preventing race walkers from reaching the speeds attainable by distance runners.

The purpose of this study was to conduct a biomechanical analysis of all 15 medallists at the 25th IAAF World Race Walking Cup in Saransk, Russia. Each of the medallists was videoed during the faster second half of the race. All senior medallists went on to compete in the Olympic Games, where two became Olympic champions for the first time. Two cameras were placed alongside the course and 3D analysis of the video data conducted in order to measure the most important variables in race walking. As expected, stride length was found to be correlated with speed, and data on individual athletes emphasised the importance of this variable. However, longer strides were negatively associated with stride frequency, and so a balance between these two fundamental variables is advisable. The athletes adhered very closely to the race walking rule with regard to having a straightened knee at first contact; however, they were closer to the threshold of visibly losing contact. While there was little variation between athletes in terms of hip and knee angles, there were larger variations found within the measurements of shoulder and elbow angles. Coaches and athletes should be mindful that race walking is a whole-body activity and inefficient movements should be identified and corrected as appropriate.

Treadmills are often used by runners when weather conditions are adverse or a specific training effect is desired. Athletes might respond to fatigue differently when running on a treadmill compared with overground conditions, where pace is typically more variable. The purpose of this study was to measure changes in gait parameters over the course of a 10-km treadmill run. Fifteen male competitive runners ran at a constant pace for 10 km at 103% of season's best time on an instrumented treadmill with in-dwelling force plates, and data were analyzed at 5 distances. Kinematic data were derived from high-speed videography and results compared between the early and late stages. Before halfway, step length increased and cadence decreased, whereas during the latter stages, there were significant decreases in impulse and maximum force. Contact time decreased and flight time increased continually, but otherwise most gait variables did not change. The changes in contact and flight times suggested that athletes altered their gait so that more time was spent airborne to allow the treadmill to pass under them. In general, however, the runners maintained their techniques throughout the run. Constant pace treadmill running might therefore be useful with the aim of running for a particular distance and speed with a consistent technique unaffected by factors such as gradient or fatigue. However, the increase in flight time might have aided the runners because of the nature of treadmill running, and athletes and coaches should note that this training effect is impractical during overground running.

PURPOSE: The aim of this study was to describe the pacing profiles used by racewalkers competing in IAAF World Championships. METHODS: The times for each 5-km segment were obtained for 225 men competing over 20 km, 214 women competing over 20 km, and 232 men competing over 50 km, of whom 49 did not finish. Athletes were grouped based on finishing position (for medalists) or finishing time. RESULTS: Different pacing profiles were used by athletes grouped by finishing time, with 20-km medalists using negative pacing and those finishing within 5% of the winning time matching the medalists' early pace but failing to maintain it. Lower-placed 20-km athletes tended to start more quickly relative to personal-best pace and experienced significant decreases in pace later. Across all competitions, the fastest finishers started the slowest relative to previous best performance. All 50-km athletes slowed toward the finish, but lower-placed finishers tended to decrease pace earlier (with up to 60% of the race remaining). After halfway in the 50-km, 8 of the 15 athletes who had a 5-km split more than 15% slower than the previous split dropped out. CONCLUSIONS: The negative pacing profile used by 20-km medalists required the ability to start fast and maintain this pace, and similarly paced training may be beneficial in race preparation. Over 50 km, the tactic of starting slower than personal-best pace was generally less risky; nonetheless, any chosen pacing strategy should be based on individual strengths.

The aim of this study was to describe pacing profiles used by senior men competing in the World Cross Country Championships. Lap times were collated for 1273 competitors across 10 races. Each individual's lap times were expressed as a percentage of the eventual winner's lap times, and athletes were grouped according to finishing position. Most athletes started the race by following the pace set by the leaders but slowed relative to the winner with each successive lap. The gold medallists were faster than the other medallists only after the final lap (P < 0.001). Most athletes who dropped out (61%) had completed the first lap within 105% of the winner's lap time. The medallists used a strategy of running close to the front from an early stage, but did not separate themselves from other top 15 finishers until halfway, with the eventual medal positions decided even closer to the finish. Athletes finishing further down had positive pacing profiles relative to the winner, possibly because of early fatigue caused by a relatively quick first lap. Athletes should note that a patient approach during the early stages can benefit not only the mass field but also those who aim to win a medal.

As the nights get darker and colder, thoughts of some runners and walkers turn to treadmill training. Dr Brian Hanley considers whether it is a good idea.

The 800 m and 1500 m are the two middle distance events contested at the Olympic Games and other major championships. On most occasions, athletes must negotiate two qualifying rounds to reach the final. The theoretically optimal method of competing in these rounds is to obtain an automatic qualifying position in the slowest possible finishing time; however, elite athletes are often ego oriented and this might have led them to try to win all races. The aim of this study was to identify whether elite athletes adopted these theoretically optimal tactics, or whether the will to win overrode them. Finishing positions and times of the eventual finalists in the men’s and women’s 800 m and 1500 m competitions at Olympic Games and IAAF World Championships between 1999 and 2017 were analysed. The performances of 606 athletes were analysed (800 m men: 122; 800 m women: 120; 1500 m men: 183; 1500 women: 181). The finalists’ finishing positions and times, as well as their overall ranking in the heats and semi-finals, were also obtained. Athletes were allocated to groups based on finishing position in the final: medallists (800 m and 1500 m), non-medallists finishing in the top eight (‘Top 8’: 800 m and 1500 m), and those athletes finishing outside the top eight (‘Top 12’: 1500 m only). One-way repeated measures ANOVA was conducted on the heat, semi-final and final finishing times. In addition, one-way ANOVA were conducted with Tukey’s post-hoc tests to compare finishing times between groups. Statistical significance was accepted as P < .05. Kendall’s tau-b (τb) correlations determined the relationships between finishing position in the final with qualifying round positional, rank and finishing time data. Across the four events, 70% of the 57 gold medallists won both qualifying rounds, whereas 36% of the silver medallists and 19% of the bronze medallists achieved the same positions. Nineteen gold medallists set a season’s best or personal best time in the final. In each event, finishing position in the final was correlated with finishing position in the heats and semi-finals (P ≤ 0.002), but not with finishing time in those rounds. In the 800 m, medallists were faster than non-medallists in the final only (P < 0.001); in the 1500 m, medallists and Top 8 finishers were faster than Top 12 finishers in the final only (P < 0.001). Most World and Olympic champions won both their heat and semi-final, even though this was unnecessary, but managed to do so with slower times than in the final. These tactics showed a long-term pacing strategy that optimised overall competition success. In addition, the gold medallists did so in most cases in times slower than their best that year. Head-to-head elite championships, where winning is more important than time recorded, encourage a performance climate for both men and women athletes where ego orientation is more likely to occur.

The aim of this study was to analyse qualification patterns in middle distance running and identify whether athletes adopt theoretically optimal tactics, or whether the will to win overrides these. The performances of 295 men and 258 women finalists in the Olympic and IAAF World Championship 800 m and 1500 m events from 1999 to 2017 were analysed across all three rounds of competition. Finishing position, time and ranking amongst all competitors were found for each athlete. Position in the final was correlated with finishing position in the heats and semi-finals (all P < 0.001), but not with finishing times in those rounds. Of the 57 champions, 40 won both their heat and semi-final, even though a lower automatic qualification position would have been sufficient, and only 18 achieved a season’s best time in the final. The will to win amongst the eventual champions (and other medallists) suggests predominantly ego oriented behaviour that is encouraged by a performance climate, and which did not appear to differ between men and women. Coaches and athletes are recommended to note that championship-specific physiological and psychological factors are important to develop in training and prior competition to improve both short- and long-term championship strategies.

The European Athletics U20 and U23 Championships are important steps in the career path of talented young athletes. Previous studies have examined how well the very best athletes from these age group championships perform in subsequent high-level competition, including the Olympic Games and IAAF World Championships in Athletics. But these events also play an important role in simply retaining talented young athletes through to the senior level, which is of interest to the wider athletics community. This study aimed to evaluate the impact of the two championships by means of a detailed analysis of the overall participation rates in the post-junior careers of talented athletes. It included examination of the differences between disciplines and nations. The results show that the two championships improve the chances that those who take part will continue competing as seniors, and that the U23 championships are particularly effective in maintaining participation between the ages of 25 and 29. The study concludes with a number of recommendations to Member Federations for supporting young athletes in their transition to the senior ranks.

How and why top-level race walkers get injured was the subject of a new study by Dr Brian Hanley.

The Grand Jete movement is a popular leap elevation movement used in ballet, modern, contemporary and jazz dance. The move involves taking off from one foot and landing on the other foot reaching the highest point possible in the air and lifting legs to a split position. Dancers may perform many grand jetes in a single routine. The aim of this study was to investigate whether footwear used by dancers can reduce the vertical impact forces caused by landing from high leaps. The study was approved by the university’s ethics committee and informed consent was given by ten highly-trained dancers (age mean 23.1, s=1.6 years; height 1.64, s=.08 m; mass 57.7, s=5.2 kg). The participants all performed a grand jete in three different footwear conditions: bare feet, jazz shoes and dance trainers with shock absorbing properties. Landing forces were recorded using a Kistler force plate sampling at 1000 Hz. Peak impact force was determined as the maximum vertical force occurring during the first 0.07 s of contact. Statistical analysis consisted of repeated measures ANOVA. Maximumforce during the landing phase decreased from 4.00 BW (s=0.72) in the barefoot condition to 3.95 BW (s=0.69) in the jazz shoes condition and 3.58 BW (s=0.68) in the trainers condition (F2,9=2.5, P=0.108, Z2=0.22, power=0.44).Higher impact peak and loading rate values were found in the barefoot condition compared to the shodconditions, with the trainers showing the lowest values. However, there were no significant differences between the footwear conditions for impact peak force(F2,9=0.50, P¼0.616, Z2=0.05, power=0.12),time-to-peak impact force (F2,9=0.44 , P=0.653, Z2=0.05, power=0.11), or loading rate to the poin of maximum vertical force (F2,9=0.53, P=0.597, Z2=0.06, power=0.12). The results showed lower maximum landing forces, impact peak force and loading rates in the dance trainers compared to the barefoot and jazz shoes conditions. Although the values were not significantly different, the small difference between footwear conditions may prove important with the onset of fatigue during a routine. Dancers should train to develop safe landing techniques when performing barefooted.

Successful shooting in netball depends not only on achieving the correct angle, velocity and height of release, but also on how well the shooter can adjust these factors when faced with a defender. However, few studies, if any, have analysed the difference between shots taken with a defender present and those without (usually due to a penalty against the defender). The aim of the study was to examine the difference in kinematic variables between defended and undefended shots during netball games. The study was approved by the university’s ethics committee and informed consent was given by eight elite netballers (age mean 22.1, s=2.3 years; stature 1.81, s=.08 m; mass 69.0, s=8.7 kg). Each participant was filmed playing in a Netball Superleague game during the 2007/2008 season. Two stationary Canon DM-XL1 digital cameras were placed on a balcony overlooking the playing area, so as not to interfere with the players or spectators. The sampling rate was 50 Hz, and the shutter speed 1/500 s. Two successful shots per player were digitised and analysed using SIMI Motion (Munich) and filtered using a Butterworth low-pass 2nd order filter. The two shots consisted of one successful defended shot, and one successful undefended shot (due to a penalty awarded against the opposing team’s defender). Statistical analysis consisted of dependent t-tests. The height of release was higher for defended shots (2.16 m, s=0.28) than in undefended shots (1.93 m, s=0.04). This was caused partially due to greater elbow extension during the shooting action. The maximum elbow angle for defended shots was 138° (s=25) and for undefended shots 108° (s=23). The significant difference found between these values (P=0.049) was the only one found between the two shooting conditions. The angle of release at the shoulder was higher for defended shots (141°, s= 22) compared to undefended (133°, s=7), as was the vertical velocity of the wrist at release (0.54 m s -1, s=0.31 and 0.43 m s -1, s=0.12 respectively). Several differences were found between shooting with and without a defender, although only one was found to be significant. Nonetheless, it was clear that shooting with a defender present required a greater height of release, and larger shooting arm joint angles. It is important for netball players and coaches to shoot with defenders present during training in order to practice the style of shooting required during a game.

The value of the European U-23 Championships in the development and maintenance of elite athletes is explored in research by Dr Brian Hanley.

The pack behaviour among long-distance runners has been explored recently in research by Dr Brian Hanley.

The aim of this novel study was to analyse performance changes across qualifying heats, semi-finals and finals in world-class sprinters and hurdlers. Finalists’ finishing positions, times and rankings at the Olympic Games and IAAF World Championships (2012 – 2019) were obtained. 78% of gold, 67% of silver and 38% of bronze medallists won their qualifying heat and semi-final, and in most events final placings were associated with finishing positions in the qualifying heats (P ≤ 0.006), but not with finishing times. Medallists ran faster in each successive round (P < 0.001), whereas those finishing between 4th-6th did not improve on their semi-final times. Most athletes finishing last and second-last ran the final slower than both their semi-final and qualifying heats. The short hurdles events, with fixed barrier heights and distances, differed from the other races as the medallists were faster than most rivals in the qualifying rounds (P < 0.05), and their race times did not improve from the semi-final to the final. Coaches should note that the world’s best athletes were able to conserve energy for the final within a meso-pacing strategy throughout the championships, which was more important in the short hurdles, and requires preparation within their training regimens.

Objectives. To compare season’s best times preceding major championships (SBprior) and times achieved in major championship flat track races. Material and methods. 2320 men’s and 2312 women’s finishing times over 100 m, 400 m, 800 m, 1500 m and 5000 m at the International Association of Athletics Federations (IAAF) World Championships and Olympic Games from 1999 to 2019, and their SBprior, were obtained via IAAF open-access website. Paired t-tests were used to compare major championship times and SBprior for groups across sex in each event. Repeated measures ANOVA was used to examine differences in the percentage of SBprior achieved in the major championship races (%SBprior) between groups and sexes. Results. Finishing time performances were generally slower than SBprior. The difference between SBprior and championship performances increased with distance run and across preliminary rounds and finals. Differences in %SBprior between sexes were found in non-medal finalists in the 800 m and 5000 m (p < 0.001, ES ≥ 0.72). Conclusions. 1500 m and 5000 m athletes competing at major championships should train and be physiologically prepared to sustain non-even paces and produce a fast endspurt to achieve an optimal performance.

The aim of this novel research was to compare the amount of systematic training and the different training activities undertaken by elite-standard long-distance runners during their first seven years of systematic training. Participants were divided into three performance groups: world-class Kenyans (N = 19), European-standard Spanish athletes (N = 18), and Spanish national-standard athletes (N = 18). Performance and training data were obtained for two-year periods using retrospective recall (including training diaries) from the time the athletes began systematic training, until the seventh year after. These activities included high-intensity training sessions considered deliberate practice (DP) and easy runs. There was no evidence that starting systematic training at a younger age was advantageous, and easy runs (a non-DP activity) were the most used by participants as a proportion of overall running distance. As part of an overall higher accumulation of distance run (P < 0.001, d ≥ 1.35), the Kenyans completed more tempo runs and short-interval training than the other groups (P < 0.001, d ≥ 1.38), but did not complete more long intervals or races. There were few differences between the European- and national-standard athletes except for easy runs, which highlights the value of these easy runs but also the need for higher-intensity training to compete with world-class performers. When planning for training overload and progression, long-distance running coaches should consider increasing the volume of tempo runs and short intervals, in addition to easier runs that develop cardiovascular conditioning.

The aim of this study was to establish whether the lane and heat draw influenced placings and progression in world-class 800-m track running. Finishing positions and times of 1086 performances at the Olympic Games and IAAF World Championships between 1999 and 2017 were obtained. Mean finishing and season’s best times (SB), as well as placings and progression rates, were found for each heat number and for the inner (Lanes 1 and 2), middle (Lanes 3 – 6) and outer lanes (Lanes 7 and 8). In the qualifying heats and semi-finals, the theoretically expected number of fastest losers (non-automatic qualifiers) per heat was compared with the actual number. One-way ANOVA with Bonferroni post hoc tests were conducted to compare finishing times between lane and heat numbers across rounds. With regard to the order of heats, there were no differences between finishing times in either the qualifying heats or semi-final rounds for men; in the women’s event, only Semi-final 3 was the quickest, but still did not have higher progression rates. SB times did not differ between heats within each round, highlighting the fair distribution of athletes. Progression rates for each lane during the qualifying heats ranged between 36% and 52% (men) and between 49% and 61% (women), close to the expected ranges of 45% and 55%, respectively. The middle lanes were quicker in the seeded semi-finals and finals only. Men in the outer lanes fared slightly worse and should focus on achieving the optimal tactical position after breaking from lanes. The IAAF could reconsider how they allocate seeded lanes in the later rounds by switching the fifth and sixth fastest athletes from the outer to the inner lanes. Regarding the heat draw, athletes mostly did not take advantage of knowing previous performances from earlier races, and probably focused on achieving an automatic qualifying position instead. However, the fastest losers in the women’s last semi-final were faster and showed that benefitting from the heat draw is possible with tactical coaching.

This dataset includes results of performances by athletes competing in global competitions since 1896 (1267 men and 803 women). All had won at least one medal at a major global championships or set a World Record (WR) ratified by World Athletics as of March 1st, 2025. World Best marathon times from before 2004 were considered WRs provided they were accepted by the International Association of Athletics Federations (IAAF). Analysed athletes competed in sprint, distance, and hurdling events.

The aims of this study were to compare marathon pacing profiles between major championships winning races and world record (WR) races in men’s and women’s long-distance runners. Percentages of mean race speeds (%RS) for each 5 km section and last 2,195 m were compared between the latest 12 men’s and 8 women’s marathon WRs and the most recent 14 men’s and 14 women’s performances leading to either World Championship or Olympic Games (championships) gold medals, and between sexes in championships, through analysis of variance. Additionally, the coefficient of variation in pace (%CV) was compared through independent samples t-tests. %RS during the first 5 km was greater in WRs than championships in men (p = 0.010, d = 1.07), with a subsequent even pacing profile. More negative pacing profiles were adopted in championships than WRs in men (p < 0.001, d = 2.07). Women’s WR and championship performances were characterized by even and negative pacing profiles, with different %CV (p < 0.001, d = 1.89). Whereas marathon WRs are characterized by fast, even and sustained paces, slower paces and more negative pacing approaches with fast endspurts are adopted during winning major championship performances. These fast endspurts are specially used by women in championships.

The differences in pacing demands between track distance-running championship and meet (e.g., World Record [WR]) races have not been specified yet in the current literature. Therefore, the aim of this study was to determine pacing behaviour differences between WRs and global championship (i.e., World Championships and Olympic Games) medal performances (GCMs) in middle- and long-distance running events. Percentages of mean race section speeds were compared through analysis of variance between men’s and women’s 169 WRs and 189 GCMs over 800m, 1500m, 3000m steeplechase, 5000m and 10,000m. U-shaped and negative pacing approaches are observed during men’s and women’s 1500m WRs and GCMs, respectively. The first and third 400 m of men’s and women’s 1500m GCMs were relatively slower and faster, respectively (p ≤ 0.05, 1.31 ≤ d ≤ 1.69). Even profiles are followed during women’s 3000m steeplechase WRs and GCMs, whereas positive approaches were adopted in men’s GCMs. Finally, whereas 5000m and 10,000m GCMs were finished with a fast endspurt, WRs had a U-shaped profile in men, with differences between the initial and last race stages (p ≤ 0.01, 1.20 ≤ d ≤ 3.66), and an even profile in women. Coaches should consider the different pacing demands existing among meet and global championship races to specifically implement training characteristics targeting either goal type.

The pacing and packing tactics of world-class marathon runners have been explored in new research by Dr Brian Hanley

The aim of this study was to analyse the biomechanical parameters of the gait cycle in world-class Kenyan runners and race walkers in a 3D analysis. It was hypothesised that race walkers’ kinetics and kinematics would differ from running at the same speed, because of the need to maintain visible contact with the ground and a straightened knee from initial contact until the vertical upright position. Twenty-One Olympic male race walkers and fifteen elite Kenyan runners were recruited for the study. Kinetic and Kinematics were collected using a 3D motion analysis system race walking and running at 12 km/h. Joint kinetics were calculated using inverse dynamics, analysing each plane with a one-dimensional statistical parametric mapping, represented by a waveform. Race walkers and runners showed differences in their gait patterns, as whereas the elite race walkers had higher ground contact times (ES=6.47), the endurance runners had longer flight times (ES=7.37) and swing times (ES=6.25). The outcome of these differences was that endurance runners used longer strides (ES=3.94) and lower cadences (ES=8.84). Both running and race walking waveforms were found to be different at heel strike for the ankle, knee and hip. The race walkers’ heel-strikes were characterised by a more (fully) extended knee (ES=3.08), more flexed ankle (ES=2.25) and less flexed hip (ES=0.56). In the other planes, higher abduction values were measured in the hip (ES=1.8) with external rotation in the ankle for the race walkers and internal rotation for the runners (ES=1.27). During the midstance phase, race walkers maintained or hyperextended the knee, whereas the runners flexed it (ES=8.55). Race walkers and runners showed similar ground reaction forces patterns during initial contact. However, the normalised initial loading rate was higher in endurance runners (p=0.011, ES=5.22). As the first study comparing elite endurance runners and elite race walkers, this study provides very useful information about the three-dimensional gait dynamics. Many differences were showed between both groups during the entire waveform running and race walking at the same speed. As it was hypothesised, due to the requirements of the rule 230.2, race walkers must adopt and optimise this peculiar gait pattern to excel in their event, thus, missing out on the elastic energy absorbed (and returned) by the knee, for example. By contrast, distance runners have no restrictions on their gait, and can therefore move in whatever way is most economical for them. Thus, these differences in the gait pattern, require race walkers a specific and more complex motor control, in addition to specific technical, strength and conditional training programs.

The aim of this study was to analyze the pacing profiles of Olympic and IAAF World Championship long distance finalists, including the relationship with their recent best times. The times for each 1,000-m split were obtained for 394 men and women in 5,000 m and 10,000 m finals at five championships. Athletes’ best times from the previous 32 months were also obtained. Similar pacing profiles were used by athletes grouped by finishing position in 5,000 m races. Women adopted a more even pacing behavior, highlighting a possible sex-based difference over this distance. Pacing behavior over 10,000 m was more similar between men and women compared with over 5,000 m. The main difference between men and women was that in the men's 10,000 m, as in the men’s 5,000 m, more athletes were able to follow the leading group until the final stages. There were large or very large correlations between athletes’ best times from the previous 32 months and their result; the fastest finishers also ran closer to their previous 32 months’ best times. Despite differences in pacing behavior between events, long distance runners should nonetheless stay close to the front from the beginning to win a medal.

The aim of this study was to determine the influence of running wide on bends regarding intermediate changes of position, dispersion of athletes, and speed relative to season best (SB) between medalists and non-medalists in men’s and women’s 800 m championship finals. Extra distance covered on bends was measured using official videos. The total distance run was calculated and described as the minimum calculable distance. Theoretical mean speeds, theoretical finishing times and theoretical finishing positions were calculated. In addition, intermediate and total changes of position (on bends and straights) and dispersion between athletes in each 100-m segment were calculated. Finishing times and segment times were calculated relative to SB. Theoretical finishing times were faster than official finishing times (p<.001). Finishing positions were influenced by extra distance covered. Medalists displayed a higher number of positive changes of intermediate positions than non-medalists (p<.001), occurring mainly on the straights (p=.003) and were greatest between 500 and 600 m (p=.003), without differences between groups in total extra distance and in extra distance covered on each bend. Medalists displayed higher total speeds relative to SB (p=.042) and over the 500-600 m segment onwards (p<.05), increasing the dispersion from this segment onwards (p<.001). These findings indicate that running the shortest distance on the bends and being able to accelerate during the last 300 m of the race positively influence finishing position in major championships 800 m finals.

The current study analysed the pacing behaviour of athletes competing in the middle-long track event finals of the IAAF Under 18 and Under 20 World Championships between 2015 and 2018. Official finishing times, 1000-m split times and positioning data of 116 female and 153 male athletes, competing in the middle-long distance running (3000 m, 5000 m and 10,000 m) and race walking (5000 m and 10,000 m) events, were gathered. Repeated measures analysis of variance, with 1000-m speed as within-subjects factor and final ranking (medallist, Top 8 or Top 12, rest of the field) as between-subjects factor, was performed to compare the pacing behaviour between athletes. Positioning of the athletes was analysed by Kendall tau-b (Tb) correlation between the intermediate position and final position. Overall, medallists increased their speed throughout a race, with the exception of the 5000 m running event, in which a parabolic pacing behaviour was exhibited. The 1000-m segment in which a significant (P > 0.05) difference in speed was exhibited between differently ranked athletes coincided with a strong (Tb > 0.7) correlation between intermediate and final positioning. These combined results point towards a separation between the athletes during the race, as the Top 8 or Top 12 and the rest of the field are unable to match the speed of the medallists. The distance, discipline, sex, age category and behaviour of competitors all influence the pacing behaviour of young track athletes during international level competition, emphasising the importance and complexity of developing adequate pacing behaviour in track athletes.

• Regulation of pace is a decision-making process that is influenced by knowledge of how far an athlete has left to run combined with an awareness of the internal physiological environment that governs the athlete’s state of fatigue. • The most frequently used pacing strategy to achieve a fast time in the 800 m event involves a positive split approach, characterised by a fast initial 200 m followed by a progressive deceleration over the remainder of the race. • In track middle-distance events (800 m and 1500 m), remaining close to the leader and avoiding running wide on bends is important for gaining qualification for subsequent rounds or winning a medal. • In events longer than 800 m, an even pace throughout is recommended to achieve the fastest possible time and finish in a high position. • Marathon runners are advised to start conservatively (based on their present fitness and target time) to avoid slowing in the second half of the race. • Running behind a pacemaker or in a pack of runners provides a large advantage by reducing the energetic cost of running and the cognitive burden associated with pace-related decision-making.

This chapter provides the important aspects of the running stride and its various components, the effects of different footstrike patterns and fatigue on running technique, and how racing conditions such as wind, hills and underfoot surface affect an athlete's biomechanics. A knowledge of the biomechanics of running is invaluable when describing an athlete's technique, explaining how they speed up or slow down and understanding the external and internal forces that cause their movements. Because people's weights vary considerably, it is quite normal in biomechanics to present force magnitudes in bodyweights, whereby the forces measured are divided by the athlete's weight. Distance running is, of course, an endurance activity, and external factors such as the effects of wind, hills, surface and rival athletes' tactics can influence the rate of fatigue. Running speed is dictated by an athlete’s step length and cadence, although step length is more important in differentiating between faster and slower runners and reduces more with fatigue.

The distribution of energetic resources in world-class distance running is a key aspect of performance, with athletes relying on aerobic and anaerobic metabolism to greater extents during different parts of the race. The purpose of this study is to model 10,000 m championship performances to enable a deeper understanding of the factors affecting running speed and, given that more than half the race is run on curves, to establish the effect of the bends on performance. Because a limitation of time split data is that they are typically averaged over 100-m or 1,000-m segments, we simulate two 10,000 m runners' performances and thus get access to their instantaneous speed, propulsive force and anaerobic energy. The numerical simulations provide information on the factors that affect performance, and we precisely see the effect of parameters that influence race strategy, fatigue, and the ability to speed up and deal with bends. In particular, a lower anaerobic capacity leads to an inability to accelerate at the end of the race, and which can accrue because of a reliance on anaerobic energy to maintain pace in an athlete of inferior running economy. We also see that a runner with a worse running economy is less able to speed up on the straights and that, in general, the bends are run slower than the straights, most likely because bend running at the same pace would increase energy expenditure. Notwithstanding a recommendation for adopting the accepted practices of improving aerobic and anaerobic metabolism through appropriate training methods, coaches are advised to note that athletes who avoid mid-race surges can improve their endspurt, which are the differentiating element in closely contested championship races.

Purpose To determine different relationships between, and predictive ability of, performance variables at intermediate distances with finishing time in elite male 10,000 m runners. Methods Official electronic finishing and 100 m split times of the men’s 10,000 m finals at the 2008 and 2016 Olympic Games and IAAF World Championships in 2013 and 2017 were obtained (125 athlete performances in total). Correlations were calculated between finishing times and positions and performance variables relating to speed, position, time to the leader and time to the runner in front at 2000, 4000, 6000, 8000 and 9900 m. Stepwise linear regression analysis was conducted between finishing times and positions and these variables across the race. One-way ANOVA was performed to identify differences between intermediate distances. Results The standard deviation and kurtosis of mean time, skewness of mean time and position and time difference to the leader were either correlated with or significantly contributed to predictions of finishing time and position at one of the analysed distance at least (0.81 ≥ r ≥ 0.30 and 0.0001 ≤ P ≤ 0.03, respectively). These variables also displayed variation across the race (0.0001 ≤ P ≤ 0.05). Conclusions The ability to undertake a high degree of pace variability, mostly characterised by acceleration in the final stages, is strongly associated with the achievement of high finishing positions in championship 10000 m racing. Furthermore, the adoption and maintenance of positions close to the front of the race from the early stages is important to achieve a high finishing position.

The middle- and long-distance running events comprise the 800 m, 1500 m, 3000 m steeplechase, 5000 m, 10,000 m and marathon. Although these events are described as race distances, it is useful for the physiologist to consider running duration, which will differ between athletes dependent on ability, age and sex (March et al., 2011), as highlighted in Figure 4.1.1. For both middle- and long-distance running, the aerobic system is the predominant contributor to energy turnover, with the proportion of energy from anaerobic sources decreasing as distance run increases (Spencer and Gastin, 2001). However, the absolute contribution of anaerobic energy might not differ greatly in well-trained athletes, especially over the shorter distances (Gastin, 2001).

The purpose of this study was to examine whether World Championship and Olympic medallist endurance athletes pace similarly to their race opponents, where and when critical differences in intra-race pacing occur, and the tactical strategies employed to optimally manage energy resources. We analyzed pacing and tactics across the 800, 1,500, 5,000, 10,000 m, marathon and racewalk events, providing a broad overview for optimal preparation for racing and pacing. Official electronic splits from men's (n = 275 performances) and women's (n = 232 performances) distance races between 2013 and 2017 were analyzed. Athletes were grouped for the purposes of analysis and comparison. For the 800 m, these groups were the medalists and those finishing 4th to 8th (“Top 8”). For the 1,500 m, the medalists and Top 8 were joined by those finishing 9th to 12th (“Top 12”), whereas for all other races, the Top 15 were analyzed (those finishing 9th to 15th). One-way repeated measures analysis of variance was conducted on the segment speeds (p < 0.05), with effect sizes for differences calculated using Cohen's d. Positive pacing profiles were common to most 800 m athletes, whereas negative pacing was more common over longer distances. In the 1,500 m, male medalists separated from their rivals in the last 100 m, whereas for women it was after 1,200 m. Similarly, over 5,000 m, male medalists separated from the slowest pack members later (4,200 m; 84% of duration) than women (2,500 m; 50% of duration). In the 10,000 m race, the effect was very pronounced with men packing until 8,000 m, with the Top 8 athletes only dropped at 9,600 m (96% of duration). For women, the slowest pack begin to run slower at only 1,700 m, with the Top 8 finishers dropped at 5,300 m (53% of duration). Such profiles and patterns were seen across all events. It is possible the earlier separation in pacing for women between the medalists and the other runners was because of tactical racing factors such as an early realization of being unable to sustain the required speed, or perhaps because of greater variation in performance abilities.

© 2019 Elsevier Ltd The aim of this study was to analyze footstrike patterns in elite marathon runners at the 2017 IAAF World Championships. Seventy-one men and 78 women were analyzed in their respective races. Athletes’ footstrike patterns were recorded (120 Hz) at approximately 8.5, 19, 29.5 and 40 km (“Laps 1 – 4”) and categorized as either rearfoot (RFS), midfoot or forefoot striking; the latter two were classified together as non-rearfoot striking (NRFS). The most common footstrike pattern was RFS, with proportions never less than 54% of men or 67% of women at any distance. There were no sex-based differences for proportion of footstrike patterns, and there were no differences between footstrike proportions when comparing the top and bottom 50% of men finishers, or between women during Laps 1 and 2. A greater proportion of the top 50% of women maintained NRFS than amongst the bottom 50%. The proportion of RFS increased with distance run in the men's race, although more than 75% of athletes across both marathons had consistent footstrike patterns between laps (79 RFS and 36 NRFS). As most athletes were RFS (including the top four finishing men), there appears to be no clear advantage to NRFS in marathon running. Coaches should note that it is normal for elite marathon runners to be either RFS or NRFS; however, forefoot striking was rare. The high proportion of athletes who maintained their footstrike pattern reflected individualized preferences for a given footstrike pattern.

The aim of this novel study was to analyze the effect of deliberate practice (DP) and easy runs completed by elite-standard and world-class long-distance runners on competitive performances during the first 7 years of their sport careers. Eighty-five male runners reported their best times in different running events and the amounts of different DP activities (tempo runs and short and long interval sessions) and 1 non-DP activity (easy continuous runs) after 3, 5 and 7 years of systematic training. Pearson’s correlations were calculated between performances (calculated using the IAAF scoring tables) and the distances run for the different activities (and overall total). Simple and Multiple Linear Regression Analysis calculated how well these activities predicted performance. Pearson’s correlations showed consistently large effects on performance of total distance (r ≥ 0.75, P < 0.001), easy runs (r ≥ 0.68, P < 0.001), tempo runs (r ≥ 0.50, P < 0.001) and short interval training (r ≥ 0.53, P < 0.001). Long interval training was not strongly correlated (r ≥ 0.22). Total distance accounted for significant variance in performance (R2 ≥ 0.57, P < 0.001). Of the training modes, Hierarchical Regression Analysis showed that easy runs and tempo runs were the activities that accounted for significant variance in performance (P < 0.01). Although DP activities, particularly tempo runs and short interval training, are important for improving performance, coaches should note that the non-DP activity of easy running was crucial in better performances, partly because of its contribution to total distance run.

Purpose: The aim of this study was to analyse the association between muscle activation patterns on oxygen cost of transport in elite race walkers over the entire gait waveform. Methods: Twenty-one Olympic race walkers performed overground walking trials at 14 km/h where muscle activity of the gluteus maximus, adductor magnus, rectus femoris, biceps femoris, medial gastrocnemius and tibialis anterior were recorded. Race walking economy was determined by performing an incremental treadmill test ending at 14 km/h. Results: This study found that more economical race walkers exhibit greater gluteus maximus (p=0.022, r=0.716), biceps femoris (p=0.011, r=0.801) and medial gastrocnemius (p=0.041, r=0.662) activation prior to initial contact and weight acceptance. Additionally, during the propulsive and the early swing phase, race walkers with higher activation of the rectus femoris (p=0.021, r=0.798) exhibited better race walking economy. Conclusions: This study suggests that neuromuscular system is optimally co-ordinated through varying muscle activation to reduce metabolic demand of race walking. These findings highlight the importance of proximal posterior muscle activation during initial contact and hip flexor activation during early swing phase are associated with efficient energy transfer. Practically, race walking coaches may find this information useful in development of specific training strategies on technique.

Much research has explored the physiological, energetic, environmental, and psychological factors that influence pacing in endurance events. Although this research has generally neglected the role of psychological variation across individuals, recent studies have hinted at its importance. Here we conducted an online survey of over 1,300 marathon runners, testing whether any of five psychological constructs—competitiveness, goal achievement, risk taking in pace (RTP), domain-specific risk taking, and willingness to suffer in the marathon—predicted slowing in runners’ most recent marathons. Analyses revealed that RTP—the extent to which runners agreed that they began the marathon at a pace that was so fast that it would jeopardize their capacity to maintain this pace throughout the event—was a robust predictor of marathon slowing. RTP proved a substantial predictor even in regression models controlling for the other psychological constructs, training, experience, and other known pacing correlates. This result suggests that marathoners consider trade-offs when making pacing decisions, and that individuals vary in their pacing decision making.

Purpose: This was the first study to analyze high-resolution pacing data from multiple global championships, allowing for deeper and rigorous analysis of pacing and tactical profiles in elite-standard middle-distance racing. The aim of this study was to analyze successful and unsuccessful middle-distance pacing profiles and variability across qualifying rounds and finals. Methods: Finishing and 100-m split speeds and season’s best times (SB) were collected for 265 men and 218 women competing in 800 m and 1500 m races, with pace variability expressed using coefficient of variation (CV). Results: In both events, successful athletes generally separated themselves from slower athletes in the final 200 m, not by speeding up, but by avoiding slowing compared with competitors. This was despite different pacing profiles between events in the earlier part of the race preceding the endspurt. Approximately 10% of athletes ran SBs, showing a tactical approach to elite-standard middle-distance racing, and possible fatigue across rounds. Men’s and women’s pacing profiles were remarkably similar within each event, but the previously undescribed seahorse-shaped profile in the 800 m (predominantly positive pacing) differed from the J-shaped negative pacing of the 1500 m. Pacing variability was high compared with world records, especially in the finals (CV: 5.2 – 9.1%), showing that athletes need to be able to vary pace and cope with surges. Conclusions: Previous studies have focussed more on athletes in finals, but the present study showed that the best athletes had the physiological capacity to vary pace and respond to surges through successive competition rounds.

Pacing behavior is typically described through graphical profiles and coefficient of variation (CV%) with respect to the mean speed of the race. Given that races during major championships are highly stochastic because of runners’ tactical behaviors, it may be valuable to use alternative methods to better describe and capture the occurrence of pacing micro-variations (i.e., sudden brief accelerations and decelerations). This is possible with short-term variability analyses.PURPOSE: To compare differences in performance and pacing micro-variations between 5000m heats and finals during two separate major championships (Beijing 2008 Olympics vs. London 2017 IAAF World Championships).METHODS: Data with 100-m section times were used to calculate overall pacing variability (standard deviations of 100-m section times; SD) and short-term pacing variability (root mean square of successive differences between 100-m section times; RMSSD) of all male participants in the heats and finals at Beijing 2008 and London 2017. CV% for individual speeds were also computed and subsequently averaged. Comparisons between heats and finals within the same sample of athletes were made with a paired t-test (p<0.05).RESULTS: The final (802±15 s) was faster than the heats (822±4 s) in Beijing 2008 (p<0.001), whereas in London 2017 the final (819±7 s) was slower (p<0.001) than the heats (806±4 s). Overall variability was lower in the final than in the heats in Beijing 2008 (0.88 vs. 0.63; p=0.007), whereas the opposite was observed in London 2017 (0.57 vs. 1.08; p<0.001). More importantly, short-term pacing variability was greater in the final of Beijing 2008 than in the heats (0.55 vs. 0.69; p<0.001) whereas it was similar between races in London 2017 (0.63 vs. 0.68; p=0.12). CV% of speeds were significantly different between heats and finals in both competitions (7.57±1.30 vs. 5.46±0.69, p<0.001, for Beijing 20018; 5.01±0.76 vs. 8.33±1.35, p<0.001, for London 2017). CONCLUSIONS: Using short-term pacing variability showed within-championship changes that overall variability did not detect. There may be advantages in using RMSSD between section times to characterize micro-variations in pace during highly stochastic track races to better understand pacing behavior.

Introduction: In distance running, pacing is characterized by changes in speed, leading to runners dropping off the leader’s pace until a few remain to contest victory with a final sprint. Pacing behavior has been well studied over the last 30 years, but much remains unknown. It might be related to finishing position, finishing time, and dependent on critical speed (CS), a surrogate of physiologic capacity. We hypothesized a relationship between CS and the distance at which runners “fell behind” and “let go” from the leader or were “outsprinted” as contributors to performance. Methods: 100-m split times were obtained for athletes in the men’s 10,000-m at the 2008 Olympics (N = 35). Split times were individually compared with the winner at the point of “falling behind” (successive split times progressively slower than the winner), “letting go” (large increase in time for distance compared with winner), or “outsprinted” (falling behind despite active acceleration) despite being with the leader with 400 m remaining. Results: Race times ranged between 26:55 and 29:23 (world record = 26:17). There were 3 groups who fell behind at ∼1000 (n = 11), ∼6000 (n = 16), and ∼9000 m (n = 2); let go at ∼4000 (n = 10), ∼7000 (n = 14), and ∼9500 m (n = 5); or were outkicked (n = 6). There was a moderate correlation between CS and finishing position (r = .82), individual mean pace (r = .79), “fell behind” distance (r = .77), and “let go” distance (r = .79). D′ balance was correlated with performance in the last 400 m (r = .87). Conclusions: Athletes displayed distinct patterns of falling behind and letting go. CS serves as a moderate predictor of performance and final placing. Final placing during the sprint is related to preservation of D′ balance.

The 400 m and 1500 m are track events that rely on different but important contributions from both the aerobic and anaerobic energy systems. The purpose of this study is to model men’s and women’s 400 m and 1500 m championship performances to gain a deeper understanding of the key mechanical and physiological factors affecting running speed and bend running using high-resolution data from live competition (10 Hz). To investigate World-class athletes’ instantaneous speeds, propulsive forces and aerobic and anaerobic energy, we model and simulate the performances of the men’s and women’s European Athletics 400 m champions, Matthew Hudson-Smith and Femke Bol, as well as the men’s European Athletics 1500 m champion, Jakob Ingebrigtsen, and the women’s European Athletics U23 1500 m champion, Gaia Sabbatini. The simulations show that a fast start is essential in both the 400 m and 1500 m because of the need for fast oxygen kinetics, with peak running speeds occurring within the first ~50 m in both events. Subsequently, 400 m athletes slow continually from this maximum speed to the finish, and a total anaerobic contribution of ~77% is found for both male and female champions. The key to faster 400 m racing is to reduce the decrease in velocity: this comes from both a high VO2 and a high anaerobic contribution. Ingebrigtsen’s winning tactic in the European 1500 m final is to adopt a very fast cruising pace from 300 m onwards that is possible because he is able to maintain a high VO2 value until the end of the race and has a large anaerobic contribution. He has fast VO2 kinetics that does not require as fast a start as his opponents, but then he speeds up in the last two laps, without a fast sprint finish. The comparison between Sabbatini’s slower and quicker races (~8 s difference) shows that it is the improvement of aerobic metabolism that has the greatest effect on 1500 m performance. Coaches should note in particular that the all-out pacing nature of the 400 m requires the prioritization of anaerobic energy system development, and those who coach the 1500 m should note the differing energy contributions between even-paced races and championship racing.

Purpose: This study determined the evolution of performance and pacing for each winner of the men’s Olympic 1500-m running track final from 1924 to 2020. Methods: Data were obtained from publicly available sources. When official splits were unavailable, times from sources such as YouTube were included and interpolated from video records. Final times, lap splits, and position in the peloton were included. The data are presented relative to 0 to 400 m, 400 to 800 m, 800 to 1200 m, and 1200 to 1500 m. Critical speed and D′ were calculated using athletes’ season’s best times. Results: Performance improved ∼25 seconds from 1924 to 2020, with most improvement (∼19 s) occurring in the first 10 finals. However, only 2 performances were world records, and only one runner won the event twice. Pacing evolved from a fast start–slow middle–fast finish pattern (reverse J-shaped) to a slower start with steady acceleration in the second half (J-shaped). The coefficient of variation for lap speeds ranged from 1.4% to 15.3%, consistent with a highly tactical pacing pattern. With few exceptions, the eventual winners were near the front throughout, although rarely in the leading position. There is evidence of a general increase in both critical speed and D′ that parallels performance. Conclusions: An evolution in the pacing pattern occurred across several “eras” in the history of Olympic 1500-m racing, consistent with better trained athletes and improved technology. There has been a consistent tactical approach of following opponents until the latter stages, and athletes should develop tactical flexibility, related to their critical speed and D′, in planning prerace strategy.

We aimed to compare differences in performance and pacing variability indices between 5000 m heats and finals during major championships in men and women. Data with 100 m time resolution were used to compare overall pacing variability (standard deviation of 100 m section times, SD; and coefficient of variation, CV%) and short-term pacing variability (root mean square of successive differences between 100 m section times, RMSSD). The changes in performance and pacing indices differed between races and competitions. For instance, the men’s final in Beijing 2008 was quicker than the heat (p < 0.01) while the CV% was reduced (p = 0.03) and RMSSD increased (p < 0.01). For women, the heats and the final exhibited a similar mean time in London 2017 (p = 0.33) but with CV% (p < 0.001) and RMSSD (p < 0.001) showing opposite trends. Individual analyses of men’s and women’s champions revealed highly individual variability metrics. The use of RMSSD can complement overall variability indices for better characterization of pacing stochasticity.

The pacing behaviors used by elite athletes differ among individual sports, necessitating the study of sport-specific pacing profiles. Additionally, pacing behaviors adopted by elite runners differ depending on race distance. An “all-out” strategy, characterized by initial rapid acceleration and reduction in speed in the later stages, is observed during 100 m and 200 m events; 400 m runners also display positive pacing patterns, which is characterized by a reduction in speed throughout the race. Similarly, 800 m runners typically adopt a positive pacing strategy during paced “meet” races. However, during championship races, depending on the tactical approaches used by dominant athletes, pacing can be either positive or negative (characterized by an increase in speed throughout). A U-shaped pacing strategy (characterized by a faster start and end than during the middle part of the race) is evident during world record performances at meet races in 1500 m, mile, 5000 m, and 10,000 m events. Although a parabolic J-shaped pacing profile (in which the start is faster than the middle part of the race but is slower than the endspurt) can be observed during championship 1500 m races, a negative pacing strategy with microvariations of pace is adopted by 5000 m and 10,000 m runners in championship races. Major cross country and marathon championship races are characterized by a positive pacing strategy; whereas a U-shaped pacing strategy, which is the result of a fast endspurt, is adopted by 3000 m steeplechasers and half marathoners. In contrast, recent world record marathon performances have been characterized by even pacing, which emphasizes the differences between championship and meet races at distances longer than 800 m. Studies reviewed suggest further recommendations for athletes. Throughout the whole race, 800 m runners should avoid running wide on the bends. In turn, during major championship events, 1500 m, 5000 m, and 10,000 m runners should try to run close to the inside of the track as much as possible during the decisive stages of the race when the speed is high. Staying within the leading positions during the last lap is recommended to optimize finishing position during 1500 m and 5000 m major championship races. Athletes with more modest aims than winning a medal at major championships are advised to adopt a realistic pace during the initial stages of long-distance races and stay within a pack of runners. Coaches of elite athletes should take into account the observed difference in pacing profiles adopted in meet races vs. those used in championship races: fast times achieved during races with the help of 1 or more pacemakers are not necessarily replicated in winner-takes-all championship races, where pace varies substantially. Although existing studies examining pacing characteristics in elite runners through an observational approach provide highly ecologically valid performance data, they provide little information regarding the underpinning mechanisms that explain the behaviors shown. Therefore, further research is needed in order to make a meaningful impact on the discipline. Researchers should design and conduct interventions that enable athletes to carefully choose strategies that are not influenced by poor decisions made by other competitors, allowing these athletes to develop more optimal and successful behaviors.

This study investigated within-session variability in treadmill running mechanics during repeated same-day runs across multiple speeds, with a secondary aim to assess how these mechanics changed with speed. Eleven team sport athletes (9 M, 2 F; 25.0 ± 3.2 years) completed three trials of 30-s treadmill runs at 10, 12, 14, 16, 18 and 20 km/h. The coefficient of variation (CV%) for step length (2.7 to 1.7%, β = -0.10, p = 0.004) and flight time (7.9 to 4.3%, β = -0.41, p < 0.001) decreased with speed, indicating greater consistency. Step length (β = 0.068), step rate (β = 0.054), flight time (β = 3.69) and horizontal work (β = 0.026) increased with speed, and contact time (β = –9.86), duty factor (β = –0.008) and vertical work (β = –0.041) decreased. These findings suggest movement patterns become more consistent at higher speeds.

The middle- and long-distance running events comprise the 800 m, 1500 m, 3000 m steeplechase, 5000 m, 10,000 m and marathon. Although these events are described as race distances, it is useful for the physiologist to consider running duration, which will differ between athletes dependent on ability, age and sex. Physiological testing is used to measure and monitor an athlete’s adaptation to training across a season or their career, notwithstanding that the best test of progression is still performance in their event itself. Laboratory assessments are used to profile the aerobic physiology of a runner. Maximal sprint speed can be assessed on a straight 50 m on a running track. Biomechanical differences between outdoor and treadmill running can occur when assessing gait spatiotemporal parameters.

The aim of this study was to determine the influence of running wide on bends on performance during major championship 1500m events. Official final race 100-m split times of 1500m finalists from two World Championships (2013 and 2017) and the 2016 Olympic Games were obtained from the open-access World Athletics website. Extra distance covered on the bends was calculated using official videos from the championships and the total distance run was described as the minimum calculable distance. Based on this measure, theoretical mean speeds, theoretical finishing times and theoretical finishing positions were calculated. Theoretical finishing times were faster than official finishing times (P < 0.001). Men and women covered a mean extra distance on the bends of 0.31 ± 0.09 and 0.38 m ± 0.17 m, respectively. Finishing positions were also influenced by extra distance covered. These findings suggest reducing extra distance run whenever possible to achieve a better finishing position during major championship races.

The purpose of this study was to measure the effects of fatigue on gait parameters during race walking. Research has shown that fatigued athletes require gait alterations in order to maintain speed. Eighteen competitive race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at three points during the 5 km walks and at four points during the 10 km walks. Repeated measures ANOVA showed that there were significant differences in impulse and contact time parameters (p < .01). The kinetic and temporal changes occurred as early as 1 km. Athletes are recommended to race at a constant pace to reduce the effects of fatigue.

Race walking is a technical event where coaches frequently use event-specific drills to develop their athletes’ strength and movement skills in training. The purpose of this study was to measure the effectiveness of six drills often used by race walkers because of their value in activating key muscles. The muscle activity of eight lower limb muscles was measured using electromyography in 10 young race walkers as they completed the six drills down a biomechanics runway. Two force plates were also used to measure contact times and flight times, and results were compared to the muscle activity recorded during normal (competition-paced) race walking. In general, the drills chosen for analysis achieved greater activation of the key muscles of the gluteus maximus, rectus femoris and vastus lateralis; however, they were not as beneficial with regard to the activity of biceps femoris and tibialis anterior, two muscles that are often injured in race walking. Coaches are advised to ensure that drills used in training are specific to their athletes’ needs and do not inadvertently lead to non-legal technique being adopted (e.g., through increased flight time).

This project aimed to explore the structural and functional properties of the triceps surae muscle-tendon complex in cyclists, triathletes, and untrained individuals. The interaction between contractile and series-elastic elements of the gastrocnemius medialis muscle-tendon unit was explored at various cycling intensities alongside kinetic and kinematic measurements of cycling performance. An understanding of the relationship between pedalling mechanical effectiveness and metabolic efficiency was also explored, as well as the impact of morphological and mechanical properties of the triceps surae on key cycling performance indicators. These measurements were compared, for the first time, between cyclists and triathletes to develop an appreciation for the chronic adaptations to different types of mechanical loading through endurance exercise. Various muscle-tendon unit differences were observed between the groups, with triathletes displaying an increased Achilles tendon thickness (p ≤ 0.048) and higher ankle joint passive stiffness (p ≤ 0.048). Cyclists tended to show poorer dorsiflexor strength compared to untrained controls (p ≤ 0.028), although triathletes did not show the same weakness. During cycling, mechanical effectiveness increased across all groups as cycling intensity increased (p < 0.001). There was also a significant shift in the ankle joint to a more dorsiflexed position (p < 0.001), which in turn led to a greater gastrocnemius medialis muscle-tendon unit range of motion (p < 0.001). However, there was no change in fascicle mechanical behaviour across the different intensities, characterised by similar fascicle range (p = 0.991) and fascicle shortening velocities (p = 0.919). The amplitude of muscle activity also increased in all muscles measured (p < 0.001). There were no between-group differences in any biomechanical, neuromechanical, or physiological parameter of cycling at any measured power output. There were very strong associations discovered between mechanical effectiveness and gross efficiency (mean r = −0.91, p < 0.001), although there were no strong associations for any kinematic, neural, or mechanical variable measured. Overall, this project showed that despite observing some structural muscle-tendon unit differences between triathletes and cyclists, there are no mechanical behavioural differences during cycling, suggesting that the adaptations that might be specific to triathlon performance do not have a beneficial or detrimental effect on cycling performance. It also showed for the first time that there are strong associations between mechanical effectiveness and metabolic efficiency, although no specific neuromechanical characteristic in the triceps surae strongly affects this relationship.

This time analysis of the women’s 1,500 m event includes the splits for each 100 m segment across heats, semi-finals and finals and is an invaluable tool for those who wish to understand the pacing patterns of elite middle distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This time analysis of the men’s 800 m event includes the splits for each 100 m segment across heats, semi-finals and finals and is an invaluable tool for those who wish to understand the pacing patterns of elite middle distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This time analysis of the women’s 800 m event includes the splits for each 100 m segment across heats, semi-finals and finals and is an invaluable tool for those who wish to understand the pacing patterns of elite middle distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

Race walking is part of the athletics programme at the Olympic Games and all other major athletics championships. Despite this high profile, no research has measured the amount of work done at the major lower limb joints, and such data might be particularly informative in this unique form of gait given its distinctive rules. The aim of this study was to measure the work done in each of the main leg joints in elite race walkers. Ten elite male race walkers (stature: 1.79 m (± 0.06); mass: 67.0 kg (± 9.4)) and 10 elite female race walkers (stature: 1.69 m (± 0.05); mass: 53.9 kg (± 5.6)) participated in the study; in total, 10 had competed at the Olympic Games. They performed multiple trials, and ground reaction forces (Kistler, Winterthur) were recorded of the contact phase (1000 Hz) and synchronised with high-speed videography (100 Hz) (RedLake, San Diego). Sagittal plane joint powers at the hip, knee and ankle were calculated from the force and video data; the amount of work done at each joint was calculated as the time integral of the power curve using the trapezoidal rule. Overall, the lower limb was a net generator of energy (16.0 ± 9.8 J), with most positive work done during stance (19.3 ± 11.0 J). The ankle was a net generator of energy, with most of this work occurring during stance (7.7 ± 5.2 J). The hip was also a net generator of energy, but with more positive work done during swing (41.4 ± 12.0 J) than during stance (15.2 ± 10.2 J). By contrast, the knee was a net dissipater of energy (–50.0 ± 12.7 J), with large negative work values occurring during swing (–46.4 ± 9.5 J). This led to a mean net dissipation of energy in the lower limb during swing (–3.2 ± 8.9 J). The main muscle groups that did positive work were the hip extensors (42.3 ± 10.1 J), hip flexors (22.4 ± 7.1 J) and ankle plantarflexors (16.4 ± 3.8 J). Most of the negative work was done by the knee flexors (–38.2 ± 7.1 J) and knee extensors (–18.7 ± 6.4 J). The hip extensors did most of the positive work during the gait cycle and emphasised their central function in elite race walking; the hip flexors were important in late stance / early swing to drive the thigh forwards, and the extensors important in late swing / early stance in preventing too much braking at initial contact. By contrast, the amount of work done by the knee during stance was minimal, and in effect, the straightened knee rule restricted the leg to the role of a rigid lever around which the body rotated because of the forward momentum of the contralateral swing leg. The key points for coaches are that the strength and endurance of the hip muscles must be well developed for elite race walking performances, and the frequent injuries to the hamstrings in race walking are most probably due to the considerable negative work done by the knee muscles during late swing.

The aim of this study was to analyse lower limb joint moments, powers and electromyography patterns in elite race walking. Twenty international male and female race walkers performed at their competitive pace in a laboratory setting. The collection of ground reaction forces (1000 Hz) was synchronised with two-dimensional high-speed videography (100 Hz) and electromyography of seven lower limb muscles (1000 Hz). As well as measuring key performance variables such as speed and stride length, normalised joint moments and powers were calculated. The rule in race walking which requires the knee to be extended from initial contact to midstance effectively made the knee redundant during stance with regard to energy generation. Instead, the leg functioned as a rigid lever which affected the role of the hip and ankle joints. The main contributors to energy generation were the hip extensors during late swing and early stance, and the ankle plantarflexors during late stance. The restricted functioning of the knee during stance meant that the importance of the swing leg in contributing to forward momentum was increased. The knee flexors underwent a phase of great energy absorption during the swing phase and this could increase the risk of injury to the hamstring muscles.

Introduction Race walking is an abnormal form of gait where no visible loss of contact with the ground is permitted and the knee must be straightened from heel strike until the ‘vertical upright position’ (IAAF rule 230.1). The absence of knee flexion during early stance does not occur in normal walking (Levine et al., 2012) and might therefore have an effect on ground reaction force (GRF) patterns. Little research has been carried out on GRFs in race walking despite the value of kinetic data in analysing this unique form of gait. The aim of this study was to measure and describe typical ground reaction force patterns of world-class race walkers. Methods Sixteen international race walkers performed multiple trials at their season’s best pace in a laboratory setting. The group consisted of nine men (stature: 1.79 m (± 0.05); mass: 68.0 kg (± 6.8)) and seven women (stature: 1.67 m (± 0.05); mass: 55.8 kg (± 3.9)). Each athlete race walked along a 45 m indoor track at a speed equivalent to their season’s best time for 20 km or 50 km. Ground reaction forces (Kistler, Winterthur) were recorded of the contact phases of both legs within the same trial (1000 Hz). Athletes completed at least ten trials each and the three closest to the target time were analysed for kinetic variables provided there was no evidence of targeting by the walker. Results In the vertical direction, a distinct impact peak was identified in the GRF traces of 13 of the 16 participants. In all those traces with an impact peak, the impact peak value was smaller than the loading peak (p < 0.001). The loading peak force was also greater than the midstance force and the push-off peak force (p < 0.001), but these two final vertical peaks were not different from each other. In the anteroposterior direction, a brief anterior impulse beginning at initial contact and lasting 17 ms (± 6) was identified in the traces of all but one participant. The following braking phase lasted 41.1% (± 5.9) of total stance time. In the mediolateral direction, there was a pattern of medially directed forces from 28.7% (± 5.1) to 62.3% (± 5.2) of total stance time, after which laterally directed forces were observed until toe-off. Discussion Although the GRFs of elite race walkers were similar to normal walking, there were some distinct differences. The final vertical push-off peak was much flatter, possibly due to the need to fully extend the knee until midstance, and to prevent vertical lift and subsequent loss of visible contact. The medially directed forces during midstance appeared to occur due to contralateral pelvic tilt which is itself a response to the fully extended knee, while the final lateral forces acted to return the pelvis to a neutral position prior to the next step. References Levine D, Richards J, Whittle MW (2012). Whittle’s Gait Analysis (5th ed.). Edinburgh, Churchill Livingstone.

Lower limb injuries are a continual and serious issue for military personnel. Such injuries have been associated with the requirement to train in military boots (MBs) and might be offset with commercial insoles. In this study, ground reaction forces were measured in seven male participants wearing running shoes (RS), MBs commonly used by Cypriot and Greek Army personnel, and the MBs with two types of shock-absorbing insole. The participants performed 4-min trials at walking pace (5 km·h-1) and running pace (10 km·h-1) at a 5% gradient on a treadmill under all four shod conditions. The treadmill incorporated two force plates under its belt, which provided measurements of key kinetic variables. During walking, RS showed significantly lower values for impact peak force (p < 0.01), maximum force (p < 0.05), and push-off rate (p < 0.05) compared with other conditions, although no significant differences were found during running. Although the RS were rated significantly more comfortable than any other condition, neither insole made the MBs more comfortable to wear. With little evidence to support wholesale adoption of insoles in MBs, their use by military personnel can only be recommended on a case-by-case basis.

This biomechanical report highlights the key kinematic variables in the women's 10,000 m race, which were measured during laps 5, 10, 15, 20 and 25. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This biomechanical and time analysis report highlights the key kinematic and pacing data from the men's 10,000 m final. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This report includes measurements of key kinematic variables in women's marathon running, including step length, step rate and joint angles of the lower and upper limbs. The report is available for download from: https://www.iaaf.org/about-iaaf/documents/research

This biomechanical report focusses on the kinematics of the top eight finishers in the men's marathon. The full report can be downloaded via the IAAF website at: https://www.iaaf.org/about-iaaf/documents/research

This time analysis of the men’s 5,000 m event includes the splits for each 100 m segment in the final and is an invaluable tool for those who wish to understand the pacing patterns of elite distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This time analysis of the women’s 5,000 m event includes the splits for each 100 m segment in the final and is an invaluable tool for those who wish to understand the pacing patterns of elite distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This time analysis of the men’s 1,500 m event includes the splits for each 100 m segment across heats, semi-finals and finals and is an invaluable tool for those who wish to understand the pacing patterns of elite middle distance runners. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

This biomechanical report focussed on the athletes as they crossed the final water jump. The analysis was broken down into three phases: the approach (including take-off characteristics), the clearance of the barrier, and the landing phase. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

The aim of this study was to analyse lower limb work patterns in world-class race walkers. Seventeen male and female athletes race walked at competitive pace. Ground reaction forces (1000 Hz) and high-speed videos (100 Hz) were recorded and normalised joint moments, work and power, stride length, stride frequency and speed estimated. The hip flexors and extensors were the main generators of energy (24.5 J (± 6.9) and 40.3 J (± 8.3) respectively), with the ankle plantarflexors (16.3 J (± 4.3)) contributing to the energy generated during late stance. The knee generated little energy but performed considerable negative work during swing (–49.1 J (± 8.7)); the energy absorbed by the knee extensors was associated with smaller changes in velocity during stance (r = .783, P < .001), as was the energy generated by the hip flexors (r = –.689, P = .002). The knee flexors did most negative work (–38.6 J (± 5.8)) and the frequent injuries to the hamstrings are probably due to this considerable negative work. Coaches should note the important contributions of the hip and ankle muscles to energy generation and the need to develop knee flexor strength in reducing the risk of injury.

This biomechanical report comprises an analysis of the final water jump, which proved to be crucial to the final race outcome. This analysis of the top eight finishers focuses on three aspects of the water jump technique: the approach, the clearance, and the landing. The full report is available from the IAAF website: https://www.iaaf.org/about-iaaf/documents/research

Abstract Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency.

The purpose of this study was to measure kinetic and kinematic variables as well as muscular activity in young international race walkers to observe any possible leg asymmetry. Five men and three women race walked on an instrumented treadmill for 3km and kinetic and kinematic data were collected at the halfway distance. The activity of four muscles on each leg was simultaneously measured using electromyography. Similar to previous findings of elite junior race walkers in competition, half of the athletes had stride length differences, but imbalances in other variables were less common. In particular, vertical ground reaction force peaks were very similar between legs. However, the electromyography findings showed that some of the athletes had substantial differences between leg muscles with regard to activation levels, and that compensation occurred between synergist muscles (gluteus maximus and biceps femoris) within the same leg. Coaches are advised to closely monitor the technical and strength development of their young athletes to ensure that both sides of the body are balanced. This is especially important with regard to preventing injury, maximising efficiency, and reducing the risk of disqualification.

The purpose of this study was to investigate variations in kinematic parameters in men's and women's 5 km road racing. Athletes often vary their pace and changes particularly tend to occur towards the end of a race due to fatigue and sprint finishes. Twenty competitive distance runners (10 male, 10 female) were videoed as they completed the English National 5 km championships. Three-dimensional kinematic data were analysed using motion analysis software (SIMI, Munich). Data were recorded at 950 m, 2,400 m and 3,850 m. Repeated measures ANOVA showed significant decreases in speed due to reduced step length and cadence in both men and women. These decreases predominantly occurred between the first two measurement points. The hip, knee, ankle and shoulder angles at both initial contact and toe-off did not change significantly, but there were significant reductions in the elbow angle for both men (at initial contact) and women (at toe-off).

Whole body digitizing used to calculate whole body center of mass (CM) variables from competitions is particularly time-consuming, and “shortcut” methods that substitute for it could expediate the calculation of spatiotemporal variables. The aim of this study was to measure the appropriateness of using the head as a proxy for the CM when calculating running velocity in competition. Fifty-six athletes in the IAAF World Championship marathons were recorded using two high-definition cameras (50 Hz) on two laps so that 112 running sequences were analyzed. The video files were imported into SIMI Motion and manually digitized. The horizontal running velocity during one gait cycle was obtained using four methods: horizontal velocity of the CM; horizontal velocity of the head (raw data); horizontal velocity of the head (Butterworth filtered); and horizontal displacement of the head (a single measurement using SIMI Motion 3D still image measurement) divided by time taken. In comparison with the criterion CM measurements for mean horizontal velocity, the filtered head data had the best 95% confidence interval (95% CI) for intraclass correlation coefficient (ICC) (0.999 – 1.000), the least bias (–0.006 m/s), and the lowest root mean square difference (0.024 m/s). The filtered head condition also had the best 95% CI for ICC for maximum and minimum horizontal velocities during the stride (>0.988) and the lowest bias (–0.001 m/s and –0.003 m/s, respectively). With the application of an appropriate filter, the head is thus an excellent proxy for whole body CM velocity calculations.

The aim of this study was to analyse key kinematic, spatiotemporal, and global mechanical characteristics in world-class middle-distance racing. Eight men were recorded halfway along the home straight on the second, third and final laps in the 2017 IAAF World Championship 1500m final. Video data (150 Hz) from three high-definition camcorders were digitised to calculate relevant variables, subsequently analysed in relation to running speed and finishing position. Better-placed finishers had greater hip extension at initial contact and through late stance, greater knee excursion throughout stance, and longer overstriding distances. Step length did not change with faster speeds as runners relied on increasing step frequency, but the highest-finishing athletes had longer contact phases and greater fluctuations in speed through the step cycle, which were related to higher normalised peak horizontal forces. The best athletes also had lower leg stiffnesses and vertical stiffnesses. The extended contact phase and greater compression could allow for more sustained force production, enabling better acceleration and maintenance of sprinting speed, indicating a trade-off between aerobic energetic efficiency and anaerobic power capacity. Coaches should note that these factors, as well as the best athletes’ greater overstriding distances, show that elite 1500m runners might prioritise a technique that favours running speed over economy.

The aim of this study was to measure differences in segment centre of mass position, velocity and acceleration in elite race walkers using two different body segment parameter models. Knowledge of how results differ between models can inform researchers as to the appropriate choice with regard to their own participants. Video data of thirty men and thirty women race walkers were recorded during competition using two camcorders operating at 50 Hz. Two popular body segment parameter models (Dempster and de Leva) were applied individually to the digitised data. Positional, velocity and acceleration values were obtained for each participant at four relevant points during the gait cycle. The whole body centre of mass vertical position was significantly lower when using the de Leva model compared to Dempster. The vertical position of the centre of the mass of the thigh was also significantly lower in women when using the de Leva model. The upper arm provided significantly different velocity and acceleration data at particular points between the models. The actual difference between positions of the centre of mass of the foot tended to be quite small. The analysis showed that the position of centres of mass (in the vertical direction) was most affected by choice of body segment parameter model. Differences in linear velocity and acceleration were largely non-significant, but extra care is advised when analysing the upper arm segment. Usage of de Leva’s model is recommended, particularly when analysing women participants.

Racewalking is a unique event combining mechanical elements of walking with speeds associated with running. It is currently unclear how racewalking technique impacts upon lower limb muscle-tendon function, despite the relevance of this to muscle economy and overall performance. The present study examined triceps surae neuromechanics in 11 internationally competitive racewalkers (age 25±11 years) walking and running on a treadmill at speeds between 4.5 - 13.8 km/h whilst triceps surae fascicle lengths, electromyography and kinematic data were recorded. Cumulative muscle activity required to traverse a unit distance (CMAPD) was calculated for each muscle. Medial gastrocnemius (MG) and soleus fascicle lengths/velocities were determined using an automated tracking algorithm, and muscle-tendon unit lengths were determined. Running was associated with net shortening of muscle fascicles during stance, combined with substantial lengthening of the muscle-tendon unit, implying energy storage in the Achilles tendon. When the same participants racewalked at the same speed, the fascicles shortened (soleus) or lengthened (MG), coinciding with rapid shortening followed by a relatively small increase in muscle tendon length during stance. Consequently, compared with running at the same speed, racewalking decreased the energy-saving role of the Achilles tendon. Moreover, CMAPD was generally highest in racewalking, implying that in individual muscles, the energy cost of racewalking was higher than running. Together these results suggest that racewalking is neurally and mechanically costly relative to running at a given speed. As racewalking events are typically between 10 and 50 km, neuromechanical inefficiencies that occur with each stride likely result in substantial energetic penalties.

World-class marathon runners make initial contact with the rearfoot, midfoot or forefoot. This novel study analyzed kinematic similarities and differences between rearfoot and non-rearfoot strikers within the men’s and women’s 2017 IAAF World Championship marathons across the last two laps. Twenty-eight men and 28 women, equally divided by footstrike pattern, were recorded at 29.5 and 40 km (laps 3 and 4, respectively) using two high-definition cameras (50 Hz). The videos were digitized to derive spatiotemporal and joint kinematic data, with additional footage (120 Hz) used to identify footstrike patterns. There was no difference in running speed, step length or cadence between rearfoot and non-rearfoot strikers during either lap in both races, and these three key variables decreased in athletes of either footstrike pattern to a similar extent between laps. Men slowed more than women between laps, and overall had greater reductions in step length and cadence. Rearfoot strikers landed with their foot farther in front of the center of mass (by 0.02 – 0.04 m), with non-rearfoot strikers relying more on flight distance for overall step length. Male rearfoot strikers had more extended knees, dorsiflexed ankles and hyperextended shoulders at initial contact than non-rearfoot strikers, whereas female rearfoot strikers had more flexed hips and extended knees at initial contact. Very few differences were found at midstance and toe-off. Rearfoot and non-rearfoot striking techniques were therefore mostly indistinguishable except at initial contact, and any differences that did occur were very small. The spatiotemporal variables that differed between footstrike patterns were not associated with faster running speeds and, ultimately, neither footstrike pattern prevented reductions in running speeds. The only joint angle measured at a specific gait event to change with fatigue was midswing knee flexion angle in men. Coaches should thus note that encouraging marathon runners to convert from rearfoot to non-rearfoot striking is unlikely to provide any performance benefits, and that training the fatigue resistance of key lower limb muscle-tendon units to avoid decreases in step length and cadence are more useful in preventing reductions in speed during the later stages of the race.

This biomechanical report focusses on the run-up characteristics of the women's pole vault final. Eleven finalists were analysed, and includes new variables that are important in successful world-class pole vaulting.

This biomechanical report focusses on the run-up characteristics of the men's pole vault final. All 15 finalists were analysed, and includes new variables that are important in successful world-class pole vaulting.

The aim of this novel study was to analyse key kinematic variables during the water jump clearance amongst world-class 3,000 m steeplechasers. Thirteen men and 13 women were recorded as they negotiated the last water jump in the 2017 IAAF World Championship finals. Video footage (100 Hz) was recorded using three high-definition camcorders to derive spatiotemporal data; spatial data were normalised to athletes’ statures. The time to cover the distance from 4.5 m before the water jump barrier to 4.5 m after (“9 m time”) was used to describe overall clearance success. Although men had longer approach and exit step lengths, there were no differences when the data were normalised; by contrast, men’s landing distances were greater in both absolute and relative terms. Women’s shorter landing distances meant negotiating deeper water when exiting, with those athletes with longer landing distances running faster 9 m times (r = –0.87). Obtaining a high position on the barrier (clearance height) was correlated with longer landing distances (men: r = 0.75, women: r = 0.71) and could indicate better technique. Coaches should note that although technical proficiency in all aspects of the clearance is imperative, optimising the athlete’s landing distance is paramount.

The 800 m race challenges the aerobic and anaerobic energy systems, and athletes adopt a technique that allows for running efficiency as well as sprinting speeds. The aim of this novel study was to compare important kinematic variables between the two laps of the 2017 IAAF World Championships women’s final. Video data (150 Hz) were collected of all eight finalists on both laps at a distance approximately 50 m from the finish line along the home straight. Running speed, step length, cadence, temporal variables, sagittal plane joint angles, and shank angle at initial contact were measured. Running speed was faster on lap 2 (p = 0.008) because of large increases in cadence (p = 0.012). These higher cadences resulted in large decreases in contact times (p = 0.031) and in flight times (p = 0.016) on lap 2. Greater knee flexion and ankle plantarflexion (p ≤ 0.039) at initial contact on lap 2 seemed partly responsible for shorter swing times (p = 0.016), and which accompanied a decrease in shank angle at initial contact from lap 1 (7°) to a more vertical position on lap 2 (4°) (p = 0.008). Coaches should note that the need for higher cadence, horizontal impulse production during shorter contact times, and the adoption of forefoot striking require strength and neural system training to allow for athletes to increase cadence during the sprint finish. Increasing cadence (and not step length) was the driving factor for faster finishing speeds in the women’s 800 m.

PURPOSE: Advanced footwear technology is prevalent in distance running, with research focusing on these "super shoes" in competitive athletes, with less understanding of their value for slower runners. The aim of this study was to compare physiological and biomechanical variables between a model of super shoes (Saucony Endorphin Speed 2) and regular running shoes (Saucony Cohesion 13) in recreational athletes. METHODS: We measured peak oxygen uptake (VO2peak) in 10 runners before testing each subject 4 times in a randomly ordered crossover design (ie, Endorphin shoe or Cohesion shoe, running at 65% or 80% of velocity at VO2peak [vVO2peak]). We recorded video data using a high-speed camera (300 Hz) to calculate vertical and leg stiffnesses. RESULTS: 65% vVO2peak was equivalent to a speed of 9.4 km·h-1 (0.4), whereas 80% vVO2peak was equivalent to 11.5 km·h-1 (0.5). Two-way mixed-design analysis of variance showed that oxygen consumption in the Endorphin shoe was 3.9% lower than in the Cohesion shoe at 65% vVO2peak, with an interaction between shoes and speed (P = .020) meaning an increased difference of 5.0% at 80% vVO2peak. There were small increases in vertical and leg stiffnesses in the Endorphin shoes (P < .001); the Endorphin shoe condition also showed trivial to moderate differences in step length, step rate, contact time, and flight time (P < .001). CONCLUSIONS: There was a physiological benefit to running in the super shoes even at the slower speed. There were also spatiotemporal and global stiffness improvements indicating that recreational runners benefit from wearing super shoes.

Prior research on the effects of fatigue during race walking has shown changes in step length and frequency (Knicker & Loch, 1990: New Studies in Athletics, 5, 25-38). It is unclear whether these changes are consistent for both legs. The purpose of the study was to investigate the differences between the legs for kinetic variables during race walking, and to measure changes occurring due to fatigue. The study was approved by the university’s ethics committee and informed consent was given by fourteen international race walkers, of whom four were female (Age mean 28.2, s = 7.4 years; stature 1.77, s = .10 m; mass 66.0, s = 11.7 kg). Each participant walked for 10 km on a treadmill (Gaitway, Traunstein). The average treadmill speed was 12.4 km•hr-1 (s = .7) and each athlete walked at a constant pace. Data were recorded using the Gaitway treadmill, which has two in-dwelling force plates (Kistler, Winterthur). The sampling rate was 1000 Hz. Data were collected for thirty seconds at four times during the walk, at 2500 m, 4500 m, 6500 m, and 8500 m. Statistical analysis consisted of repeated measures ANOVA. There was a significant difference between the legs for first peak force (F1,13 = 32.6, P = .001, eta2 = .71, power = .99), weight acceptance rate (F1,13 = 14.5, P = .002, eta2 = .53, power = .94), and push-off rate (F1,13 = 36.2, P = .001, eta2 = .74, power = 1), although these differences did not change significantly with distance walked. There was also a significant difference between the legs’ step lengths (F1,13 = 30.1, P = .001, eta2 = .70, power = .99), midsupport forces (F1,13 = 9.6, P = .009, eta2 = .42, power = .82), and propulsive force peaks (F1,13 = 20.6, P = .001, eta2 = .61, power = .99); the overall values for these variables also increased significantly with distance walked (P < .001, P = .009, and P < .001 respectively). However, there was no effect of distance on the differences between the legs for any variable. The results show significant leg dominance during race walking. Athletes should be aware that these imbalances need rectification to prevent injury and maintain efficient walking technique. The imbalances did not appear to worsen with the onset of fatigue although this may occur over the longer championship distances of 20 and 50 km.

IAAF Rule 230.2 states that racewalkers must have no visible (to the human eye) loss of contact with the ground and that their advancing leg must be straightened from first contact with the ground until the “vertical upright position.” The aims of this study were first to analyze racewalking judges' accuracy in assessing technique and, second, to measure flight times across a range of speeds to establish when athletes were likely to lose visible contact. Twenty racewalkers were recorded in a laboratory using a panning video camera (50 Hz), a high-speed camera (100 Hz), and three force plates (1,000 Hz). Eighty-three judges of different IAAF Levels (and none) viewed the panned videos online and indicated whether each athlete was racewalking legally. Flight times shorter than 0.033 s were detected by fewer than 12.5% of judges, and thus indicated non-visible loss of contact. Flight times between 0.040 and 0.045 s were usually detected by no more than three out of eight judges. Very long flight times (≥0.060 s) were detected by nearly all judges. The results also showed that what judges generally considered straightened knees (>177°) was close to a geometrically straight line. Within this inexact definition, IAAF World Championship-standard Level III judges were most accurate, being more likely to detect anatomically bent knees and less likely to indicate bent knees when they did not occur. For the second part, the men racewalked down a 45-m indoor track at 11, 12, 13, 14, and 15 km/h in a randomized order, whereas the women's trials were at 10, 11, 12, 13, and 14 km/h. Flight times, measured using an OptoJump Next photocell system (1,000 Hz), increased for the men from 0.015 s at 11 km/h to 0.040 s at 14 km/h and 0.044 s at 15 km/h, and for the women from 0.013 s at 10 km/h to 0.041 s at 13 km/h and 0.050 s at 14 km/h. For judging by the human eye, the threshold for avoiding visible loss of contact therefore occurred for most athletes at ~14 km/h for men and 13 km/h for women.

Introduction Race walking is an Olympic event dictated by a rule that states that no visible loss of contact with the ground should occur and that the leg must be straightened from first contact with the ground until the ‘vertical upright position’ (IAAF Rule 230.2). The measurement of contact and flight times during race walking is therefore of great interest to coaches and athletes. The aim of the study was to compare the effects of changes in speed on temporal variables in elite race walking during treadmill and overground race walking. Methods Eleven male race walkers (stature: 1.77 m (± 0.06), mass: 64.4 kg (± 4.7)) and eight female race walkers (stature: 1.67 m (± 0.09), mass: 56.1 kg (± 10.3)) participated. Fifteen of the athletes had competed at the 2016 Olympic Games or 2017 World Championships. For the overground condition, the men race walked multiple times down a 45-m indoor track at 11, 12, 13, 14 and 15 km/h in a randomised order, whereas the women’s trials were at 10, 11, 12, 13 and 14 km/h. Contact and flight times were measured for each trial using five connected 1 m strips of an OptoJump Next system (1000 Hz). For the treadmill condition (conducted on a separate day), each athlete race walked on a treadmill at five speeds for 3 min each. The speeds chosen were the same as during the overground condition and were conducted in a randomised order after a 10-min warm-up and familiarisation period. Results from the OptoJump Next system were extracted using specific settings based on the number of LEDs found optimal during a reliability study; for the overground tests, this setting was 2_2, whereas for the treadmill tests it was 0_0. Results For the overground condition, the values changed as follows (contact time / flight time): men – 11 km/h: 0.327 s / 0.015 s; 12 km/h: 0.304 s / 0.025 s; 13 km/h: 0.281 s / 0.035 s; 14 km/h: 0.267 s / 0.040 s; 15 km/h: 0.251 s / 0.044 s. For women, the values changed as follows – 10 km/h: 0.331 s / 0.012 s; 11 km/h: 0.307 s / 0.022 s; 12 km/h: 0.286 s / 0.033 s; 13 km/h: 0.269 s / 0.040 s; 14 km/h: 0.248 s / 0.049 s. For the treadmill condition, the values changed as follows: men – 11 km/h: 0.313 s / 0.021 s; 12 km/h: 0.296 s / 0.029 s; 13 km/h: 0.279 s / 0.038 s; 14 km/h: 0.261 s / 0.047 s; 15 km/h: 0.247 s / 0.053 s. For women, the values changed as follows – 10 km/h: 0.319 s / 0.023 s; 11 km/h: 0.293 s / 0.036 s; 12 km/h: 0.276 s / 0.045 s; 13 km/h: 0.258 s / 0.054 s; 14 km/h: 0.245 s / 0.059 s. Discussion Although it was unsurprising that contact time decreased with increased walking speed, and that there was a concurrent increase in flight time, what was interesting was that women had higher flight times when their speeds were matched with the men’s. Women therefore need to be more careful about displaying visible loss of contact. In addition, flight times tended to be higher during treadmill race walking at the same speed as overground (and contact times lower), suggesting that treadmill training could induce non-legal technique.

The aim of this study was to analyze changes in gait variability and symmetry in distance runners. Fourteen competitive athletes ran on an instrumented treadmill for 10,000 m at speeds equivalent to 103% of their season's best time. Spatiotemporal and ground reaction force data were recorded at 1500, 3000, 5000, 7500 and 9500 m. Gait variability and inter-leg symmetry were measured using median absolute deviation (MAD) and the symmetry angle, respectively. There were no overall changes during the running bout for absolute values, symmetry angles or variability, and there were only moderate changes in variability between successive testing distances for three variables. Even with these few changes, variability was low (<4%) at all distances for all variables measured and, on average, the athletes were symmetrical for five of the seven gait variables measured. There were greater mean asymmetry values for flight time (1.1–1.4%) and for impact force (2.0–2.9%), which might have occurred because of muscle latency as the lower limb responded passively to impact during initial contact. Although most athletes were asymmetrical (>1.2%) for at least one variable, no one was asymmetrical for more than four of the seven variables measured. Being asymmetrical in a few variables is therefore not abnormal and not indicative of asymmetrical gait and given many practitioners analyze symmetry (and variability) on an individual, case-study basis, caution should be taken when assessing the need for corrective interventions.

Race walking is an Olympic event dictated by a rule that states that no visible loss of contact with the ground should occur and that the leg must be straightened from first contact with the ground until the ‘vertical upright position’ (IAAF Rule 230.2). The measurement of flight times during race walking is therefore of great interest to coaches, athletes and judges. The aim of the study was to compare different methodologies used to measure contact and flight time in race walking. Ten male race walkers (stature: 1.78 m (± 0.05), mass: 64.4 kg (± 4.9)) and seven female race walkers (stature: 1.68 m (± 0.10), mass: 56.7 kg (± 11.0)) participated. Fourteen of the athletes had competed at the 2016 Olympic Games or 2017 World Championships. The men race walked down an indoor track at 11, 12, 13, 14 and 15 km/h (measured using timing gates and in a randomised order), whereas the women’s trials were at 10, 11, 12, 13 and 14 km/h. Contact and flight times were measured for the midsection of each trial using three adjacent 900 x 600 mm Kistler force plates (1000 Hz), 5 x 1 m strips of an OptoJump Next system (1000 Hz) and a Fastec high-speed camera (500 Hz). Results from the OptoJump Next system were extracted using five settings based on the number of LEDs that needed activating (contact begins after_contact ends when), and were annotated as 0_0, 1_1, 2_2, 3_3 and 4_4. The force plate values were considered the criterion values and measurements were assessed for reliability using Intraclass Correlation Coefficients (ICC) and 95% limits of agreement (LOA: bias ± random error). For flight time, the ICCs between the force plate and OptoJump Next were 0.846 for the 0_0 condition (LOA: .011 ± .014 s), 0.901 (1_1) (LOA: .008 ± .014 s), 0.983 (2_2) (LOA: .000 ± .008 s), 0.844 (3_3) (LOA: –.011 ± .014 s), and 0.563 (4_4) (LOA: –.023 ± .018 s). The ICC between the force plate and the high-speed video for flight time was 0.975 (LOA: –.003 ± .008 s). For contact time, the ICCs between the force plate and OptoJump Next were 0.967 for the 0_0 condition (LOA: –.011 ± .011 s), 0.982 (1_1) (LOA: –.008 ± .010 s), 0.995 (2_2) (LOA: .000 ± .010 s), 0.960 (3_3) (LOA: .011 ± .016 s), and 0.874 (4_4) (LOA: .024 ± .015 s). The ICC between the force plate and the high-speed video condition for contact time was 0.991 (LOA: .004 ± .010 s). The OptoJump Next system provided results similar to those of the gold standard force plates, with the 2_2 setting the most reliable. Users of the OptoJump Next system should therefore note that adjusting the settings of the device (from 0_0, the most likely default setting) might be necessary to achieve the most accurate results. The high-speed video recordings also provided very good reliability although the time-consuming nature of video analysis means the OptoJump Next system is better suited to providing immediate results.

The aim of this study was to analyse changes in gait variability and symmetry with increasing speed in race walkers. Eighteen international athletes race walked on an instrumented treadmill at speeds of 11, 12, 13 and 14 km·h-1 in a randomised order for 3 min each. Spatiotemporal and ground reaction force data were recorded for 30 s at each speed. Gait variability was measured using median absolute deviation and inter-leg symmetry was measured using the symmetry angle. There was an overall effect of speed on all absolute values except push-off force, but symmetry and variability (except flight time) did not change with increased speed, step length and step frequency. Most athletes were asymmetrical for at least one variable, but none was asymmetrical for more than half of the variables measured. Therefore, being asymmetrical or having higher variability (<5%) in a few variables is normal. Taking all findings together, practitioners should exercise caution when deciding on the need for corrective interventions and should not be concerned that increasing gait speed could increase injury risk through changes to athletes’ asymmetry. Race walking coaches should test at competition speeds to ensure that flight times, and any variability or asymmetry, are measured appropriately.

Racewalking is an Olympic event where athletes are not permitted a visible loss of contact, with the result that competitors try to minimise flight times. The accuracy of measurements taken during testing is dependent on valid and reliable systems to determine temporal values. The aim of the study was to compare different methodologies used to measure contact and flight times in overground and treadmill racewalking. Eighteen racewalkers completed overground and instrumented treadmill trials at 5 speeds, during which flight and contact times were measured using the OptoJump Next photocell system (1000 Hz), high-speed videography (500 Hz), and force plates (1000 Hz). Results from OptoJump Next were extracted using 5 settings based on the number of light emitting diodes (LEDs) activated (GaitIn_GaitOut), and annotated as 0_0, 1_1, 2_2, 3_3 and 4_4. Regarding flight time measurements for the overground condition, the 2_2 LED setting had the best 95% confidence interval (95% CI) for Intraclass Correlation Coefficient (ICC) (0.978 – 0.988), the least bias (0.000 s), and the lowest random error (0.008 s). For the treadmill condition, the 0_0 LED setting had the best 95% CI for ICC (0.890 – 0.957), the least bias (0.004 s), and the lowest random error (0.017 s). Although high-speed videography also provided highly reliable results, the equally reliable and quicker availability of results using OptoJump Next is beneficial in laboratory-based testing. Coaches and researches are advised to alter the system’s LED settings as appropriate, and to report these settings with their findings.

The aim of this study was to analyse gait variability and symmetry in race walkers. Eighteen senior and 17 junior athletes race walked on an instrumented treadmill (for 10 km and 5 km, respectively) at speeds equivalent to 103% of season’s best time for 20 km and 10 km, respectively. Spatio-temporal and ground reaction force (GRF) data were recorded at 2.5 km, and at 4.5, 6.5 and 8.5 km for a subsection of athletes. Gait variability was measured using median absolute deviation (MAD) whereas inter-leg symmetry was measured using the symmetry angle. Both groups showed low variability for step length (< 0.9%), step frequency (< 1.1%), contact time (≤ 1.2%) and vertical peak force values (< 5%), and neither variability nor symmetry changed with distance walked. Junior athletes were more variable for both step length (P = 0.004) and loading force (P = 0.003); no differences for gait symmetry were found. Whereas there was little mean asymmetry overall, individual analyses identified asymmetry in several athletes (symmetry angle ≥ 1.2%). Importantly, asymmetrical step lengths were found in 12 athletes and could result from underlying imbalances. Coaches are advised to observe athletes on an individual basis to monitor for both variability and asymmetry.

The presence of barriers in the steeplechase increases energy cost and makes successful pacing more difficult. This was the first study to analyze pacing profiles of successful (qualifiers for the final / Top 8 finalists) and unsuccessful (non-qualifiers / non-Top 8 finalists) Olympic steeplechasers across heats and finals, and to analyze differences between race sections (e.g., water jump vs. home straight). Finishing and section splits were collected for 75 men and 84 women competing at the 2008 and 2016 Olympic Games. Competitors were divided into groups based on finishing position (in both rounds analyzed). After a quick opening 228 m (no barriers), men who qualified for the final or finished in the Top 8 in the final had even paces for the first half with successive increases in speed in the final three laps; unsuccessful pacing profiles were more even. Successful women had mostly even paces for the whole race, and less successful athletes slowed after Lap 2. Women started the race relatively faster than men, resulting in slower second half speeds. The best men completed most race sections at the same speed, but less successful men were slower during the water jump section, suggesting less technically proficiency. Similarly, women were slower during this section, possibly because its landing dimensions are the same as for men and have a greater effect on running speed. Coaches should note the different pacing profiles adopted by successful men and women steeplechasers, and the importance of technical hurdling skills at the water jump.

Over the past five decades, running has become increasingly popular across the world. Although running is accessible to many people and is associated with numerous health benefits, it also carries a risk of sustaining a running related injury (RRI) (Malisoux et al., Citation2020). Of these RRIs, understanding the biomechanical changes and issues runners’ face when transitioning to a new pair of shoes is of special interest and not well understood.

The purpose of this study was to measure and analyse ground reaction force variables during race walking. Fourteen national level race walkers, eight men and six women, walked at race pace over two force plates recording at 1000 Hz. Men and women had comparable force trace patterns except for the magnitude of the weight-loading peak force. There were similarities with normal ground reaction force patterns, although the drop in vertical force at midstance and subsequent rise in vertical push-off force typical of normal walking were not observed. This was considered to be due to the straightened knee rule of race walking and the need to reduce vertical displacment and flight time. The medial forces were greater than those in normal walking and this may be related to the frontal plane motions of the pelvis.

Prior research on the effects of fatigue during race walking has shown changes in step length and frequency (Knicker & Loch, 1990: New Studies in Athletics, 5, 25–38). It is unclear whether these changes are consistent for both legs. The purpose of the study was to investigate the differences between the legs for kinetic variables during race walking, and to measure changes occurring because of fatigue. The study was approved by the university’s ethics committee and informed consent was given by fourteen international race walkers, of whom four were females (age mean 28.2, s=7.4 years; stature 1.77, s=0.10 m; mass 66.0, s=11.7 kg). Each participant walked for 10 km on a treadmill (Gaitway, Traunstein). The average treadmill speed was 12.4 km h-1 (s=0.7) and each athlete walked at a constant pace. Data were recorded using the Gaitway treadmill, which has two in-dwelling force plates (Kistler, Winterthur). The sampling rate was 1000 Hz. Data were collected for 30 s at four times during the walk, at 2500 m, 4500 m, 6500 m and 8500 m. Statistical analysis consisted of repeated measures ANOVA. There was a significant difference between the legs for first peak force (F1,13=32.6, P¼0.001, Z2=0.71, power=0.99), weight acceptance rate (F1,13=14.5, P=.002, Z2=0.53, power=0.94), and push-off rate (F1,13=36.2, P=0.001, Z2=0.74, power=1), although these differences did not change significantly with distance walked. There was also a significant difference between the legs’ step lengths (F1,13=30.1, P=0.001, Z2=0.70, power=0.99), midsupport forces (F1,13=9.6, P=0.009, Z2=0.42, power=0.82), and propulsive force peaks (F1,13=20.6, P=0.001, Z2=0.61, power=0.99); the overall values for these variables also increased significantly with distance walked (P<0.001, P=0.009, and P<0.001 respectively). However, there was no effect of distance on the differences between the legs for any variable. The results show significant leg dominance during race walking. Athletes should be aware that these imbalances need rectification to prevent injury and maintain efficient walking technique. The imbalances did not appear to worsen with the onset of fatigue although this may occur over the longer championship distances of 20 and 50 km.

The purpose of this study was to measure kinetic variables during race walking. Forty national and international race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at the 2.5 km point. Men had longer step lengths than women and walked faster as a result. There was little difference in cadence. Average flight times for each group of athlete were approximately 0.04 s. Senior athletes showed more ‘typical’ race walking vertical force patterns than the juniors; this may be linked to quantity of training experience and gait efficiency. Athletes are advised to develop muscular strength endurance to cope with loading rates upon initial contact.

Although race walkers are not permitted a visible flight phase, previous research has found that most competitors do experience very brief losses of contact. The purpose of this study was to assess the role of the flight phase in elite race walking. Seventeen international athletes race walked over two force plates recording at 1000 Hz. Video data were simultaneously recorded at 100 Hz and used to calculate kinematic variables such as step length. The mean flight time was 0.030 s (± .011) while the mean distance travelled during this phase was 0.12 m (± .05). It was calculated that without flight times, athletes would have slower mean velocities, particularly if mean cadence remained the same. However, the contribution of flight phases in race walking does not just allow for greater step lengths and faster speeds, but also more time for lower limb repositioning.

The purpose of this study was to measure and analyse the important angular kinematic variables in elite race walking. Research has shown that these variables include knee angle at contact and midstance, rotation of the hips and shoulders, and hip extension velocity. Eighty elite race walkers were videoed during competition and analysed using 3D-DLT with SIMI Motion. The knee angle was found to be almost straight at contact in most athletes and hyperextended by the vertical upright position. Athletes varied in the amount of rotation at the hips and shoulders, with 50 km men having greater hip rotation and 20 km women having greater shoulder rotation. There was much more variation in the values found for elbow and shoulder angles. Very few angular measurements correlated with key race walking variables such as speed, step length and cadence.

AIM: Successful coaching in race walking requires a thorough understanding of the biomechanical principles underlying this unique form of gait. The purpose of this study was to analyze elite male and female junior race walkers and identify key kinematic variables. METHODS: Twenty junior men and 20 junior women were videoed as they competed over 10 km in the 8th European Cup Race Walking. Three-dimensional kinematic data were obtained using motion analysis software (SIMI, Munich). RESULTS: Step length and cadence were correlated with speed in both sexes, and greater step lengths were the kinematic reason for junior men's faster walking speeds. While cadence did not differ between junior men and junior women, there was a difference in proportion of step time spent in contact. There were some differences between genders for upper body joint angles (e.g., elbow) but there were few differences within lower limb joint angles. CONCLUSION: Although some technical aspects (e.g., pelvic and shoulder girdle rotation) appeared undeveloped, it was noteworthy that most athletes achieved full knee extension at initial contact in accordance with the rules. However, in many athletes flight times were evident that might present problems during the transition to the higher standards of senior competition. There was a large range of ability among both sexes and coaches are advised to ensure that technical development continues during the transition to senior competition.

The purpose of this study was to compare knee muscle activity in race walkers with different knee extension patterns. Three international athletes walked over two force plates recording at 1000 Hz. Video data were simultaneously recorded at 100 Hz; the digitised data were combined with the force data to calculate net muscle moments and joint powers. EMG testing was carried out on three muscles which cross the knee. The two walkers with legal techniques had similar moment and power patterns, whereas the non-legal walker experienced a longer period of eccentric flexor moment at the beginning of stance, which may have affected his ability to extend his knee correctly. After this, all three athletes experienced a period of isometric contraction at the knee. Achieving correct technique requires both strength endurance exercises and mobility development.

INTRODUCTION: Research shows a lower energy cost in athletes using Advanced Footwear Technology (so called “super shoes”), but this has mainly focussed on well-trained runners. It is not clear whether such super shoes benefit recreational marathon runners at slower paces. The aim of this study was to compare physiological and biomechanical variables between a model of super shoes (Saucony Endorphin Speed 2) and regular running shoes (Saucony Cohesion) in recreational athletes. METHODS: Ten participants (1.66 ± 0.04 m, 57.1 ± 3.8 kg, 23.3 ± 1.1 y) began an incremental treadmill test at a running speed corresponding to 50-60% VO2 max. Speed increased by 1 km·h-1 every 2 min until exhaustion. Gas collection was performed during the last 60 s of each stage to attain steady state VO2. The VO2peak was calculated with the speed at VO2peak (vVO2peak) determined as the lowest running speed that elicited a VO2 equivalent to VO2peak. Participants subsequently ran four times in a randomly ordered cross-over design for 5 min (super or normal shoe, at 65% or 80% vVO2 max). Video data were recorded (Casio EX-F1 camera, 300 Hz) during the last 30 s of the 1st and 5th min, with VO2 measurements collected during the 5th min. Averaged contact and flight times during 10 consecutive steps were used to calculate step rate and step length. Vertical and leg stiffness were calculated using the methods of Morin et al. (2005). Two-way ANOVA (α < 0.05) was used to identify differences between shoes and running speeds for O2 consumption and heart rate (HR), and three-way ANOVA (shoes x speed x time elapsed) was used for spatiotemporal and stiffness variables. RESULTS: O2 consumption in the Endorphin was 3.9% and 5% lower than the Cohesion shoe at 65% vVO2 max (~9.4 km·h-1) and 80% vVO2 max (~11.2 km·h-1) accordingly (P < 0.001). HR was lower (1.8%) in the Endorphin shoe (P < 0.001), although there was no shoe-speed interaction for this variable. The Endorphin condition had shorter step lengths (0.7 - 1.0%), higher step rates (0.7-1.4%), shorter contact times (2.0 - 2.7%) and longer flight times (4.8 - 7.9%) (P < 0.001). All these variables changed with increased speed (P < 0.001). For global stiffness characteristics, vertical stiffness and leg stiffness were greater in the Endorphin shoes (1.6 - 3.3% and 4.6 - 6.3% accordingly, P < 0.001). Peak vertical force and vertical stiffness both increased with speed (P < 0.001). CONCLUSION: There was a physiological benefit to running in the super shoes as O2 consumption and heart rate were lower than in the regular shoe. The difference in O2 consumption did increase at the faster speed (5%), but nonetheless there was still a 3.9% advantage at the slower speed. The physiological benefits were accompanied by spatiotemporal and global stiffness benefits to wearing the super shoes, indicating that recreational runners gain a mechanical advantage by using this kind of footwear. REFERENCES: 1) Morin et al., JAB, 2005, 21(2), 167–180.

The purpose of this study was to examine the technique of elite junior race walkers competing at the 8th European Cup Race Walking. Both the junior men’s and junior women’s races were videoed with two cameras placed at the side of the course where the athletes passed on every lap. Analysis of twenty competitors in each race was completed. Both stride length and stride frequency were greater in the fastest groups of athletes. Stride length differences between left-to-right and right-to-left strides were noticeable in a number of athletes and these imbalances should be rectified to improve walking efficiency and reduce risk of injury. Flight times were short in the majority of athletes and slower athletes displayed no loss of contact. Athletes were also capable of maintaining straight knees from contact to the vertical upright position. However, many athletes appeared inefficient with regard to rotational motions, with poor pelvic rotation and ungainly arm movements. Junior athletes should spend time developing their technique in order to improve efficiency, reduce the risk of injury, and lessen the chance of disqualification. Training programmes to develop both muscular power and endurance are recommended to develop prepare junior athletes for the demands of senior level competitions.

The 23rd World Race Walking Cup was a very successful event with an excellent course, large numbers of spectators, and outstanding individual performances. The purpose of this study was to examine the walking techniques of the top finishers in the three senior races. Each race was videoed with two cameras placed at the side of the course where the athletes passed on every lap. Analysis of the top eight 20K women, top eight 50K men, and the 3rd to 10th place finishers in the men’s 20K was completed. The results showed that a balance between maintaining a long stride and a high cadence was crucial in achieving success. Because of the limitations of the specific race walking rules, the hip and ankle muscles must have the requisite power and endurance to develop and maintain high speeds. Men and women differ in the amount of rotation that occurs at the hips and shoulders. Men are able to attain longer strides by moving their hips through larger ranges of movement. In contrast to the joint angles of the legs, there was a large variation in the angles of the shoulders and elbows. It is advisable for athletes to concentrate on maintaining efficient technique in training and in competition.

The aim of this study was to measure and analyse the important kinematic variables in elite race walking. Research has shown that these key variables include step length, cadence, positions of the body segments and joint angles. Video recordings of eighty race walkers were taken during competition at the 7th European Cup Race Walking in 2007. These athletes included 50K men walkers as well as 20K men and women. The 20K men were faster than 50K men due to higher cadences, while both male groups were faster than women due to having longer steps. The fastest athletes overall had step lengths of approximately 70% of body height. Athletes with step lengths of this proportion were also able to maintain high cadences. 20K men had higher cadences due to longer flight times. Joint angles did not appear to be important to walking speed; instead it was the speed of movements at the joints that were important. Twelve competitors in each race were analysed at three other points in their race to assess any symptoms of fatigue. On average, all groups of athletes slowed down as the race progressed. In men, this was mostly due to shorter step lengths; in women, it was due to lower cadences. Nearly all athletes adhered to the straight leg rule of race walking but most had short, normally undetectable flight times. 50K men had knee contact angles which decreased significantly with fatigue; this leads to an increased risk of disqualification.

Race walking is an endurance event which also requires great technical ability, particularly with respect to its two distinguishing rules. The 50 km race walk is the longest event in the athletics programme at the Olympic Games. The aims of this observational study were to identify the important kinematic variables in elite men's 50 km race walking, and to measure variation in those variables at different distances. Thirty men were analysed from video data recorded during a World Race Walking Cup competition. Video data were also recorded at four distances during the European Cup Race Walking and 12 men analysed from these data. Two camcorders (50 Hz) recorded at each race for 3D analysis. The results of this study showed that walking speed was associated with both step length (r=0.54,P=0.002) and cadence (r=0.58,P=0.001). While placing the foot further ahead of the body at heel strike was associated with greater step lengths (r=0.45,P=0.013), it was also negatively associated with cadence (r= -0.62,P<0.001). In the World Cup, knee angles ranged between 175 and 186° at initial contact and between 180 and 195° at midstance. During the European Cup, walking speed decreased significantly (F=9.35,P=0.002), mostly due to a decrease in step length between 38.5 and 48.5 km (t=8.59,P=0.014). From this study, it would appear that the key areas a 50 km race walker must develop and coordinate are step length and cadence, although it is also important to ensure legal walking technique is maintained with the onset of fatigue.

Race walking is a complex activity that relies on considerable power generation by the muscles at the hip joint. Little is known, however, whether differences are present in terms of muscle activity patterns between men and women, or between younger and older athletes. The purpose of this study was to compare hip muscle activity patterns in elite male and female race walkers across U20 and senior age groups. Ten male and ten female race walkers participated, with five U20 and five senior athletes of each gender. The athletes were recorded using high-speed videography (100 Hz) as they race walked down a 40 m runway, during which the muscle activity of the gluteus medius, gluteus maximus, biceps femoris and rectus femoris was recorded using electromyography (EMG) (1000 Hz). The hip sagittal angle was calculated from digitised data, and average rectified EMG used to identify visual differences between groups. No differences were found using ANOVA between any groups for the activity of any of the four muscles analysed at toe-off, midswing, heel-strike and midstance, although there were visual differences in activity timings. Overall the few differences between groups showed that race walking techniques are comparable across trained athletes and coaches can adopt similar training practices when developing the muscular qualities of their athletes.

The 3rd European Race Walking Conference took place at Leeds Beckett University, Leeds, England, from 11-13 November 2016. Organised by a team from one of Europe’s top hubs for race walking, the National Centre for Race Walking Foundation, with support from European Athletics, the conference attracted 59 participants from 10 nations. The programme reflected the current race walking environment with examples of good practice based on athlete-centred philosophies. It included keynote presentations from both the organises and guest speakers, workshops and a special in-depth roundtable discussion led by members of the athlete support team for Tom Bosworth (GBR) who placed 6th in the Men’s 20km Walk at the 2016 Olympic Games with a UK Record performance of 1:20:13. This report provides an overview of the conference by giving descriptions of the weekend’s sessions.

The aim of this study was to analyse the important kinematic variables in elite men's and women's 20 km race walking. Thirty men and 30 women were analysed from video data recorded during the World Race Walking Cup. Video data were also recorded at four points during the European Cup Race Walking and 12 men and 12 women analysed from these data. Two camcorders operating at 50 Hz recorded at each race for 3D analysis. The two main performance determinants of speed were step length and cadence. Men were faster than women because of their greater step lengths but there was no difference in cadence. A reduction in step length was the initial cause of slowing down with later decreases in speed caused by reductions in cadence. Shorter contact times were important in optimising both step length and cadence, and faster athletes tended to have longer flight times than slower athletes. It was less clear which other kinematic variables were critical for successful walking, particularly with regard to joint angles. Different associations were found for some key variables in men and women, suggesting that their techniques may differ due to differences in height and mass.

The aim of this study was to measure and assess the biomechanical efficiency of elite race walkers. Thirty-six athletes were videoed at four different points during the 7th European Cup Race Walking. Twelve of these athletes competed in the men’s 20 km race, twelve in the women’s 20 km race, and twelve in the men’s 50 km race. Kinematic variables such as step length, pelvic rotation and knee angles were measured. Additionally, twenty-seven athletes (eighteen men and nine women) walked on a treadmill with in-built force plates in a laboratory setting. In this part of the study, variables of interest included impact force, propulsive force and base of support. Race walking utilised pelvic rotation and pelvic tilt much more than normal walking, due partially to fully straightened knees from contact to the vertical upright position. These pelvic movements also prevented the athletes’ centres of mass from rising too high. Force trace analysis showed that senior athletes had more efficient and typical race walking patterns than junior athletes, which may be an indicator of less training experience. Analysis of the effects of fatigue showed that important variables such as step length changed over the course of the walk. The 50 km men had knee contact angles that decreased significantly with fatigue and were therefore more likely to be disqualified in the later stages of the race.

The aim of this study was to examine spatiotemporal and joint kinematic differences between footstrike patterns in 10,000m running. Seventy-two men’s and 42 women’s footstrike patterns were analysed during laps 5, 10, 15, 20 and 25 (of 25) using 2D video recordings. Approximately 47% of men were FFS throughout the race, 30% were MFS and 24% RFS; the respective frequencies in women were approximately 30%, 38% and 32%. Overall, 83% of men and 88% of women retained their footstrike pattern throughout the race. Amongst the 53 men and 33 women with symmetrical footstrike patterns, there were no differences in speed, step length or cadence between footstrike groups in either sex. Most lower limb joint angles did not change in these athletes during the event, with few differences between footstrike patterns apart from ankle and foot angles. A greater hip-ankle distance was found in RFS than in FFS (both sexes) and in RFS than in MFS (men only), although these differences were never more than 0.03 m. Coaches should note that habitual footstrike patterns were maintained during this long-distance track race despite changes in running speed and possible fatigue, and there were few performance differences between footstrike patterns.

The aim of this study was to examine biomechanical differences between footstrike patterns in elite 10,000m racing. Video data of 53 men and 33 women were recorded in competition and used to compare spatiotemporal and joint kinematic variables between rearfoot, midfoot and forefoot strikers, and to find associations. There were no differences between footstrike patterns for speed, step length or cadence, but rearfoot strikers had longer contact times than forefoot and midfoot strikers by 0.017 and 0.014 s, respectively, and shorter flight times by 0.023 and 0.021 s, respectively. The main causes of different footstrike patterns were the ankle and foot angles at initial contact; thigh, knee and shank angles differed little. In women, longer hip-ankle “overstriding” distances were associated with faster running speeds (r = 0.58), and so were a positive contributor to performance.

The aim was to assess concurrent validity and test-retest reliability of spatiotemporal gait parameters from a thoracic placed inertial measurement unit (IMU) in lab- (Phase One) and field-based (Phase Two) conditions. Spatiotemporal gait parameters were compared (target speeds 3, 5 and 7.5 m·s-1) between a 100-Hz IMU and an optical measurement system (OptoJump Next, 1000 Hz) in 14 trained individuals (Phase One). Additionally, 29 English Premier League football players performed weekly 3x60-m runs (5 m·s-1; observations =1227; Phase Two). Mixed effects modelling assessed the effect of speed on agreement between systems (Phase One), and test-retest reliability (Phase Two). IMU step time showed strong agreement (<0.3%) regardless of individual or running speed. Direction of mean biases up to 40 ms for contact and flight time depended on the running speed and individual. Step time, length and frequency were most reliable (Coefficient of variation = 1.3-1.4%) but confounded by running speed. Step time, length and frequency derived from a thoracic-placed IMU can be used confidently. Contact time could be used if bias is corrected for each individual. To optimise test-retest reliability, a minimum running distance of 40 m is needed to ensure 10 constant-speed steps are gathered.

SURFACE INSTABILITY DOES NOT ADVERSELY AFFECT DROP JUMPING PERFORMANCE: A MULTI-VARIABLE BIOMECHANICAL INVESTIGATION Pollitt L, Hanley B, Bissas A Leeds Beckett University, UK Introduction Currently, despite the widespread practical use of surface instability training, little is known about its long-term effects, or about the effect it has on stable surface performance once its demands have been removed. The purpose of this study was to conduct a multi-variable biomechanical evaluation of the effects of adaptation to progressive drop jump (DJ) training conducted with varying levels of landing surface stability. Methodology 42 physically active males were exposed to 8 weeks of DJ training using increasing drop heights (i.e., 0.2m to 1.0m) onto Mini-Trampoline, BOSU, Stable, or Mix (BOSU & Stable) landing surfaces. A Control group was also included. Pre and post-testing (DJ1.0m, DJ0.6m, DJ0.2m and CMJ) was conducted on a stable surface where kinetic, kinematic, and EMG data were collected. Additional to independent analyses of these systems, muscle moment-power, work-energy and mechanical stiffness data were also constructed to provide an insight into the internal mechanisms of training adaptions. The multi-variable approach yielded a vast array of related variables. For example, dissection of the force-time curve into 66 variables and EMG analysis of specific 50ms windows including identification of the short, medium and long latency reflex responses. Results The most important finding was that exposure to landing surface instability did not adversely affect muscle activation, mechanical work and stiffness or energy contributions across joints. Only select changes in neural and mechanical variables reached statistical significance. Improvements in reactive strength index for the surface instability groups at DJ1.0m (18-37%), DJ0.6m (14-28%), DJ0.2m (16-43%), were similar to the Stable group (25, 31 & 21%). Significant improvements in comparison to the Control group (p<0.05) were found for the BOSU and Stable groups at each drop height. Discussion The absence of any adverse effects in neuromuscular or mechanical variables following surface instability training provides a new insight into the ability of the human body to adapt performance while learning new movement patterns. Essentially, the inclusion of instability with DJ training is as effective as stable landing surface conditions. The findings also suggest that when adaptations are made to the imposed demands, the adverse effects associated with surface instability have been overstated and that the principle of training specificity is not violated. Furthermore, incorporating surface instability may be beneficial to the principle of variability and as an independent consideration within an athletic training cycle, where it could reduce loading demands or be used in combination with skill acquisition, while maintaining levels of performance enhancement similar to those provided by stable conditions.

Introduction: Chronic exposure to strenuous mechanical loading has been shown to alter muscle neuromechanical behaviour during locomotion (Bissas et al., 2020) and mechanical profiles such as joint moment-angle relationships (Herzog et al., 1991). These adaptations might be movement-specific, although there is a lack of empirical evidence showing whether changes to muscle-tendon mechanical profiles translate to improved neuromechanical performance during movement. Therefore, the purpose of the study was to compare muscle-tendon profiles in trained cyclists, triathletes, and untrained controls, and to quantify neuromechanical characteristics during steady state cycling. Methods: Twenty-nine participants (10 cyclists, nine triathletes and, 10 controls) cycled at four intensities (150, 200, 250, and 300 W). Measurements of pedal forces (Radlabor, Germany), joint kinematics (Qualisys, Sweden), muscle activity (Delsys, USA), and fascicle mechanical behaviour of the gastrocnemius medialis (Telemed, Lithuania) were measured during the final minute of each 5-min trial. In addition, muscle-tendon morphological and mechanical properties were measured in the form of B-mode ultrasound (Siemens, Germany) to obtain muscle and tendon thickness, fascicle length, and pennation angle, as well as isometric/isokinetic dynamometry (Biodex, USA) to obtain passive ankle stiffness, moment-angle, and moment-velocity profiles. Results: Increases in pedal kinetics, ankle dorsiflexion angle, and normalised muscle activity were observed with an increase in exercise intensity (all p < 0.001). However, there were generally no differences in fascicle mechanical function (fascicle range, shortening velocity, pennation angle change), although some changes in muscle gearing were observed. There were also no differences between groups at any exercise intensity. There were typically no differences in isometric/isokinetic strength between groups. However, triathletes had a higher Achilles tendon thickness across multiple sites and a higher passive stiffness than the other groups (p ≤ 0.048). Conclusion: The triceps surae behave like a strut during cycling, transferring forces from proximal joints to the pedal. We showed that this behaviour is consistent across exercise intensities and between trained and untrained populations, concluding that the requirements and subsequent performance of the ankle plantarflexors at these intensities are unaffected by chronic exposure to loading. The tendon morphological and mechanical adaptations seen in triathletes appear to be specific to, or at least caused by, running but these do not lead to any neuromechanical differences during cycling. References: Bissas, A., Havenetidis, K., Walker, J., Hanley, B., Nicholson, G., Metaxas, T., Christoulas, K., Cronin, N. J. (2020). Scand J Med Sci Sports, 30, 1151-1162. Herzog, W., Guimaraes, A., Anton, M., Carter-Erdman, K. (1991). Med Sci Sports Exerc, 23, 1289-1296.

The sprint hurdle events require athletes to cross ten hurdles between the start and finish line. The height of the hurdles, and the distances between them, differ for men and women, possibly resulting in technical differences. The aim of this study was to provide a kinematic comparison of in-competition hurdle technique for world-class men and women hurdlers. Video data were collected for the 16 finalists in the 100 m and 110 m hurdles events at the 2017 IAAF World Championships using four high-speed cameras (150 Hz), focusing on the sixth hurdle for the men and fifth for the women. Center of mass (CM) position, joint angles, step lengths and clearance times were compared between sexes at key events before, during and after hurdle clearance. The hurdle height was ~7% higher for men when calculated as a proportion of stature (p < 0.001). This discrepancy in relative hurdle height provided women with a kinematic and mechanical advantage over men as they took off farther from the hurdle (relative to hurdle height) (p < 0.001), leading to a lower and more efficient flight parabola. Women were also able to maintain longer relative step lengths after hurdle clearance and showed minimal vertical oscillation of the CM in the stance phases before and after the hurdle compared with men. The lower relative hurdle heights in the women's event provide a less demanding task, and thus these findings present preliminary evidence to those coaches who advocate revising the women's hurdle heights in competition.

Introduction: Measurements of passive stiffness (PS) are often used to quantify the passive resistance of a muscle-tendon unit (MTU) to stretching, which is interesting in populations who undergo chronic loading and/or excessive stretching through exercise (Moltubakk et al., 2018). This metric may also be used to monitor the ‘neuromuscular condition’ of a participant taking part in experiments involving multiple visits. However, the repeatability of PS measurements has yet to be established. Methods: Twenty-nine participants (10 cyclists, nine triathletes and 10 controls) carried out an ankle PS test on three separate occasions. Testing was carried out on an isokinetic dynamometer (Biodex, USA) throughout each participant’s individually determined range of motion (ROM). Passive joint moments at a common angle (5° dorsiflexed) and at individual peak dorsiflexion were measured during slow (10°/s), passive rotation. PS was calculated as the leading edge of a 4th-order polynomial of the moment-angle curve (Moltubakk et al., 2018) at the same locations as passive moment. For a subset of data (n=11), the right gastrocnemius medialis was imaged using a 60 mm linear array ultrasound probe (Telemed, Lithuania) to measure fascicle length change during passive dorsiflexion. This was used to deconstruct the changes in MTU length (Fukunaga et al., 2001; Hawkins & Hull, 1990). Results: Although ankle ROM showed moderate agreement between the three sessions, passive joint moment showed lower repeatability, both at the common ankle angle and individual peak dorsiflexion. PS at the same locations showed similar repeatability, although these values were more repeatable in the triathletes who showed higher absolute PS values. For the subset of MTU data, both fascicle range and series-elastic element range show poor repeatability between sessions. However, changes in series-elastic element range were associated with a change in passive moment at peak dorsiflexion and ankle ROM (r-values: 0.568 – 0.876). Conclusion: The use of a standardised PS test does not show good repeatability across the whole population. Some between-group variation was observed, suggesting this methodology is more repeatable for certain athlete populations. Based on the MTU data, changes in ankle ROM, and thus changes in some PS parameters, are associated with changes in series-elastic element range, but not the contractile element. It remains to be determined whether between-session variation in PS parameters is caused by physiological changes to the MTU or whether the methodology itself is reliable. Investigating group-based and individual differences here could provide further evidence.

Racewalking is an unconventional form of competitive gait that elicits a unique loading profile on lower limb muscles and tendons. This study mapped the structural and mechanical properties of lower limbs in competitive racewalkers and made associations with World Athletics competition performance points. Fourteen international racewalkers (seven men, seven women) were recruited for this study. Static ultrasonography was used to quantify muscle and tendon morphological characteristics. An isokinetic dynamometer was used to measure passive musculotendinous stiffness of the triceps surae, isometric (seven knee/ankle angle combinations) and isokinetic (four angular velocities) strength parameters in the plantarflexors and dorsiflexors, and isokinetic knee flexion and extension strength at five angular velocities. Correlations were found between performance and fascicle length of gastrocnemius medialis (r = –0.569, p = 0.034), dorsiflexor strength at 120°/s (r = 0.649, p = 0.016) and knee flexor strength at 30°/s (r = 0.632, p = 0.020). No associations were found for isometric plantarflexion or passive stiffness properties. Overall, the study showed various morphological and mechanical properties are associated with performance in competitive racewalkers. These associations seem to be related to the specific and unique biomechanical characteristics of racewalking.

Midfoot- (MFS) and forefoot-striking (FFS) runners usually switch to rearfoot-striking (RFS) during marathons. However, world-class runners might resist modifications during shorter races. The purpose of this study was to analyse footstrike patterns, ground contact times and running speeds in a World Championship men’s 10,000 m final. Footstrike patterns and contact times of the top 12 finishing men (24 ± 5 years) were recorded (150 Hz) during laps 1, 5, 11, 15, 20 and 25. Split times for each 100-m segment were obtained. No RFS patterns were observed; there was no difference between the number of FFS and MFS athletes at any distance (p ≥ 0.581) and no change in the proportions of FFS and MFS occurred (p = 0.383). No link between race performance and footstrike pattern appeared given the similar number who used FFS or MFS and their similar finishing times. Despite slower running speeds and longer contact times in the middle of the race (p ≤ 0.024), no effect on footstrike patterns occurred. The prevalence of anterior footstrike patterns in this world-class race reflects the capability of maintaining fast paces (>22 km/h). Changes in footstrike pattern might accompany the physiological and neuromuscular effects of fatigue over longer distances.

The aims of this project were to conduct scientific research on race walking with regard to judging, and through the findings in this report to provide educational support to the IAAF for race walk judges, coaches and athletes. The study was conducted in two parts: the first involved inviting race walkers from around the world to be analysed in the biomechanics laboratories at Leeds Beckett University; the second part involved sharing the videos of the athletes with judges around the world who assessed the athletes for their adherence to IAAF Rule 230.2.

Race walking is an event where the knee must be straightened from first contact with the ground until midstance. The aim of this study was to compare knee angle measurements between 2D videography and 3D optoelectronic systems. Passive retroreflective markers were placed on the right leg of 12 race walkers and 3D marker coordinate data captured (250 Hz), with 2D video data (100 Hz) recorded simultaneously. Knee angle data were first derived based on the markers’ coordinates, and separately by using a 3D model that also incorporated thigh and shank clusters; the video data were analysed using both automatic tracking and manual digitising, creating four conditions overall. Differences were calculated between conditions for stance (using root mean square values), and at discrete events. There were few differences between systems, although the 3D model produced larger angles at midstance than using automatic tracking and marker coordinates (by 3 – 6°, P < 0.05). These differences might have occurred because of how the 3D model locates the hip joint, and because of the addition of marker clusters. 2D videography gave similar results to the 3D model when using manual digitising, as it allowed for errors caused by skin movement to be corrected.

The aim of this study was to analyze the link between the upper and lower body during racewalking. Fifteen male and 16 female racewalkers were recorded in a laboratory as they racewalked at speeds equivalent to their 20-km personal records [men: 1:23:12 (±2:45); women: 1:34:18 (±5:15)]; a single representative trial was chosen from each athlete for analysis and averaged data analyzed. Spatial variables (e.g., stride length) were normalized to stature and referred to as ratios. None of the peak upper body joint angles were associated with speed (p < 0.05) and there were no correlations between pelvic motion and speed, but a medium relationship was observed between peak pelvic external rotation (right pelvis rotated backwards) and stride length ratio (r = 0.37). Greater peak shoulder extension was associated with lower stride frequencies (r = −0.47) and longer swing times (r = 0.41), whereas peak elbow flexion had medium associations with flight time (r = −0.44). Latissimus dorsi was the most active muscle at toe-off during peak shoulder flexion; by contrast, pectoralis major increased in activity just before initial contact, concurrent with peak shoulder extension. Consistent but relatively low rectus abdominis and external oblique activation was present throughout the stride, but increased in preparation for initial contact during late swing. The movements of the pelvic girdle were important for optimizing spatiotemporal variables, showing that this exaggerated movement allows for greater stride lengths. Racewalkers should note however that a larger range of shoulder swing movements was found to be associated with lower stride frequency, and smaller elbow angles with increased flight time, which could be indicative of faster walking but can also lead to visible loss of contact. Coaches should remember that racewalking is an endurance event and development of resistance to fatigue might be more important than strength development.

Race walking is an event dictated by a rule that states that no visible loss of contact with the ground should occur and that the leg must be straightened from first contact with the ground until the ‘vertical upright position’ (IAAF Rule 230.2). During competition, compliance with the rule is assessed subjectively by judges but during biomechanical testing it is important to measure the knee angle objectively and accurately. The aim of this study was to compare the measurement of knee angles between 2D video and 3D optoelectronic systems during race walking. Seven elite male race walkers (stature: 1.77 m (± 0.03), mass: 65.7 kg (± 6.2)) and six elite female race walkers (stature: 1.66 m (± 0.08), mass: 58.6 kg (± 9.1)) participated in the study; in total, eight had competed at the Olympic Games. 2D video data were collected at 100 Hz using a high-speed camera. A 12-camera 3D optoelectronic motion capture system (Qualisys) operating at 250 Hz simultaneously captured the motion of three lower leg markers. The video files were digitised in two ways: first, through manually digitising by a single experienced operator; and second, using SIMI Motion’s automatic tracking function to track the three retroreflective markers. The optoelectronic files were processed through Qualisys Track Manager. All sets of knee angle data were filtered using residual analysis and interpolated to 101 points using a cubic spline. The root mean square difference (RMSD) between conditions was calculated for each individual, averaged across their five trials, and then averaged across all participants. The RMSD between the two visual digitising methods for one gait cycle was 3° (± 1). The RMSD between manual digitising and Qualisys was 4° (± 1), whereas between automatic tracking and Qualisys it was 2° (± 1). At initial contact, the mean angle calculated using manual digitising was 181° (± 2), using automatic tracking 180° (± 4), and using Qualisys 180° (± 4). The maximum angle during midstance was 185° (± 4) using manual digitising, 183° (± 5) using tracking, and 183° (± 5) using Qualisys. The minimum angle during midswing was 100° (± 6) using manual digitising, 102° (± 5) using tracking, and 101° (± 5) using Qualisys. Overall, all three methodologies gave similar results with no difference greater than 2° at any discrete gait event. It was unsurprising that the automatic tracking function in SIMI Motion and Qualisys produced similar knee angles given they used the same three joint markers, and showed that any movement of the athletes’ lower limbs out of the sagittal plane had little effect on joint angle calculation. In practical terms, using a markerless, 2D video system gave similar results to using a 3D optoelectronic system, meaning that it is appropriate for analysing in competition.

The pole vault is a highly technical event where the athletes must successfully convert horizontal velocity during the run-up to vertical velocity at take-off. The aim of this study was to compare the kinematics of men's and women's world-class pole vaulting. Video data were collected of the best clearances by 14 men and 11 women at the 2018 IAAF World Indoor Championships using three high-speed cameras (200 Hz). Running velocity, step lengths, step times, and pole angles were measured during the run-up; during take-off, distance from the plant box, angle and velocity of take-off, and relative positions of the foot and hands were measured. Men achieved greater clearance heights with faster run-ups, faster take-off velocities and higher hand grip positions (all p < 0.001), with each of the last three steps longer for men when expressed as absolute values (all p < 0.001), but not when expressed relative to stature. There were no differences in run-up pole angles, step times, take-off angle, take-off contact time or time from pole plant to take-off. Women differed in their approach and take-off for characteristics affected by stature and strength, such as fewer run-up steps, shorter take-off distances, and lower grip heights. These lower grips result from a shorter, lighter pole, and this disadvantage was greater than slower run-up velocities. Coaches should therefore note that sex-based differences occur in the pole vault that result from anthropometric differences, but which do not negate the adoption of similar technical models of vaulting.

We mapped structural and functional characteristics of muscle‐tendon units in a population exposed to very long‐term routine overloading. Twenty‐eight military academy cadets (age = 21.00 ± 1.1 years; height = 176.1 ± 4.8 cm; mass = 73.8 ± 7.0 kg) exposed for over 24 months to repetitive overloading were profiled via ultrasonography with a senior subgroup of them (n = 11; age = 21.4 ± 1.0 years; height = 176.5 ± 4.8 cm; mass = 71.4 ± 6.6 kg) also tested while walking and marching on a treadmill. A group of eleven ethnicity‐ and age‐matched civilians (age = 21.6 ± 0.7 years; height = 176.8 ± 4.3 cm; mass = 74.6 ± 5.6 kg) was also profiled and tested. Cadets and civilians exhibited similar morphology (muscle and tendon thickness and cross‐sectional area, pennation angle, fascicle length) in 26 out of 29 sites including the Achilles tendon. However, patellar tendon thickness along the entire tendon was greater (P < .05) by a mean of 16% for the senior cadets compared with civilians. Dynamically, cadets showed significantly smaller ranges of fascicle length change and lower shortening velocity in medial gastrocnemius during walking (44.0% and 47.6%, P < .05‐.01) and marching (27.5% and 34.3%, P < .05‐.01) than civilians. Furthermore, cadets showed lower normalized soleus electrical activity during walking (22.7%, P < .05) and marching (27.0%, P < .05). Therefore, 24‐36 months of continuous overloading, primarily occurring under aerobic conditions, leads to more efficient neural and mechanical behavior in the triceps surae complex, without any major macroscopic alterations in key anatomical structures.

This study aimed to compare joint kinematics and center of mass parameters throughout hurdle clearance between world-class men and women sprint hurdlers, who were competing in a World Championships final. This was the first study to present time-series kinematic data around hurdle clearance, and given the technical ability of the athletes analyzed, it can be used as a template when analyzing the technique of other athletes in similar competitions and training. Video data were collected of the 16 finalists at the 2017 IAAF World Championships using four high-speed cameras (150 Hz). Video files were continuously digitized manually from touchdown before hurdle clearance to toe-off after landing around the sixth hurdle for men and the fifth hurdle for women, and sex-based comparisons were made at key discrete time points using independent t-tests, and throughout the entire hurdle phase using statistical parametric mapping. When calculated relative to hurdle height, the women's center of mass height was significantly greater than the men's throughout the full analyzed sequence (p < 0.001). Men also displayed more hip flexion in the lead leg at take-off before hurdle clearance (p = 0.029) as well as a more extended knee joint at intervals during flight and upon landing (p ≤ 0.037). Women completed the hurdle phase in a significantly shorter time than men (~11% difference, p < 0.001). Finally, women seemed to be more efficient by maintaining and even exceeding their entry velocity for the first 40% of the hurdle phase. These results show a lower technical demand for the women to successfully negotiate hurdle clearance, thus providing further evidence to support the argument that the women's hurdle height is too low for their performance capabilities and should be raised in senior competition.

The effect of the inclusion of a high hurdle 13.72 m after the start line on elite sprint start and initial acceleration technique has yet to be investigated or understood. This highly novel study addresses that lack of information in an exceptional manner, through detailed biomechanical analysis of the world's best sprint and hurdle athletes, with data collected in situ at the 2018 IAAF World Indoor Championships, held in Birmingham, UK. High speed videos (150 Hz) were compared for eight sprinters and seven hurdlers for the start and initial acceleration phase of the finals of the men's 60 m and 60 m hurdles. Temporal and kinematic data were supplemented by vector coding analysis to investigate mechanisms by which these world-class athletes translate their centres of mass (CM) up to the fourth touchdown post-block exit. The sprinters and hurdlers coordinated their lower limb and trunk movement in a similar manner throughout the start and initial acceleration phases, which contributes new conceptual understanding of the mechanisms that underpin start and initial acceleration performance. Differences between groups were initiated from block set-up, with the hurdlers utilising a larger block spacing, but with the front block nearer to the start line than sprinters. Even after accounting for stature, the biggest differences in the raising of the CM occurred during the block phase, with hurdlers greater than sprinters (difference in vertical CM displacement scaled to stature = −0.037, very large effect size). Subsequent flight phases showed the biggest differences in the translation of the CM, in part due to longer flight times in the hurdlers, whilst the techniques of the two groups generally converged during the ground contact phases of initial acceleration. In highlighting that similar techniques are used by world-class sprinters and hurdlers, despite differing task constraints, this study has provided invaluable insights for scientists, coaches, and athletes, that will inform further developments in understanding and practice across both sprints and hurdles.

Measurements of muscle-tendon unit passive mechanical properties are often used to illustrate acute and chronic responses to a training stimulus. The purpose of this study was to quantify the inter-session repeatability of triceps surae passive stiffness measurements in athletic and non-athletic populations, with the view to discussing its usefulness both as a muscle-tendon profiling tool and a control measure for studies with multiple data collection sessions. The study also aimed to observe the effects of quiet standing on passive stiffness parameters. Twenty-nine men (10 cyclists, nine triathletes, 10 controls) visited the laboratory on three separate occasions, where passive stiffness tests were carried out using an isokinetic dynamometer and B-mode ultrasound. Participants were fully rested on two of the sessions and subjected to 20 min of quiet standing in the other. The passive stiffness assessment generally showed only moderate inter-session repeatability but was still able to detect inter-group differences, with triathletes showing higher passive stiffness than cyclists (p < 0.05). Furthermore, quiet standing impacted passive stiffness by causing a reduction in ankle joint range of motion, although mechanical resistance to stretch in the muscle-tendon unit at a given joint angle was relatively unaffected. These findings show that passive stiffness assessment is appropriate for detecting inter-group differences in the triceps surae and even the effects of a low-intensity task such as quiet standing, despite showing some inter-session variation. However, the inter-session variation suggests that passive stiffness testing might not be suitable as a control measure when testing participants on multiple sessions.

Information on how race walkers modulate lower body kinematics with speed is of interest to coaches for developing informed training strategies for elite athletes. Seven male Olympic race walkers volunteered to participate in the study. Twelve optoelectronic cameras (Oqus 7, Qualisys) operating at 250 Hz collected kinematic data as participants race walked at 3 different speeds down the 40 m walkway. Statistical parametric mapping (spm1d.org) was used to compare lower body kinematics in Matlab (R2016b, The Mathworks Inc.). Greater hip flexion (4°) was observed at 80-92% of the gait cycle in the 10 km trials than the training pace trials (p < 0.001, medium effect (0.65)). A more flexed hip during terminal swing in the 10 km trials might be indicative of the 0.08 m increase in step length that was present with increases in race walking speed. At the knee, greater flexion (3°) occurred during the 10 km trials than the training pace trials at 68-73% (p < 0.001, medium effect (0.5)). This study suggests that elite race walkers modulate lower body kinematics by increasing range of motion of the hip and knee as speed increases. Coaches and athletes should consider an individualised approach to this kinematic strategy with respect to the rules of race walking.

Previous research that has identified sex-based differences in race walking gait has only considered joint positions at discrete time points such as initial contact and toe-off, potentially missing important data that occur between these gait cycle events. Therefore, the aim of this study was to compare full body kinematic waveforms of race walking gait between elite male and female race walkers. With institutional ethics approval, 15 male race walkers (mean age: 26 ± 5 years; stature: 1.78 ± 0.04 m; body mass: 64.7 ± 4.9 kg), and fifteen female race walkers (mean age: 28 ± 6 years; stature: 1.65 ± 0.08 m; body mass: 54.1 kg ± 8.4 kg) volunteered to participate in the study. Participants race walked down a 40 m walkway at speeds relative to their 10 km personal best. Twelve optoelectronic cameras (Oqus7, Qualisys) operating at 250 Hz recorded three-dimensional kinematic data from 64 retroreflective markers. Kinematic data were processed (QTM 2.17, Qualisys), time-normalised and filtered (Visual3D v5, C-motion). Statistical parametric mapping (spm1d.org) independent samples t-tests were computed for comparisons in Matlab (R2016b, The Mathworks Inc.) with an alpha level of 5%. Overall, there were very few kinematic differences between male and female race walkers. Women had more thorax rotation: just after (0-9%, P = 0.015) and before (92-100%, P = 0.015) initial contact they were more externally rotated than men. During late stance and early swing, women were more internally rotated (56-13%, P < 0.001). Women also had greater internal pelvic rotation after initial contact (~3-5%, P = 0.033), and hip internal rotation during stance (18-26%, P < 0.001). Women’s knees extended more just before toe-off (46%, P = 0.021), and flexed less during swing (61-63%, P = 0.033). Finally, women also had greater ankle dorsiflexion immediately after (0-3%, P = 0.020) and immediately before (95-100%, P = 0.010) initial contact. The greater thorax rotation could be explained by women’s smaller upper body segments, which require greater rotation to compensate for smaller moments of inertia. Greater dorsiflexion around initial contact is thought to enhance step length by increasing the effective leg length by projecting the heel forwards (Murray et al., 1983. The American Journal of Sports Medicine, 11, 68-74), and could be a compensatory mechanism for shorter leg lengths. Despite largely similar race walking gait patterns, coaches should be mindful of the subtle differences between elite male and female race walking kinematics.

English Premier League soccer players run at multiple speeds throughout a game. The aim of this study was to assess how well the duty factor, a dimensionless ratio based on temporal variables, described running styles in professional soccer players. A total of 25 players ran on an instrumented treadmill at 12, 16, and 20 km/h. Spatiotemporal and ground reaction force data were recorded for 30 s at each speed; video data (500 Hz) were collected to determine footstrike patterns. In addition to correlation analysis amongst the 25 players, two groups (both N = 9) of high and low duty factors were compared. The duty factor was negatively correlated with peak vertical force, center of mass (CM) vertical displacement, and leg stiffness (kleg) at all speeds (r ≥ −0.51, p ≤ 0.009). The low duty factor group had shorter contact times, longer flight times, higher peak vertical forces, greater CM vertical displacement, and higher kleg (p < 0.01). Among the high DF group players, eight were rearfoot strikers at all speeds, compared with three in the low group. The duty factor is an effective measure for categorizing soccer players as being on a continuum from terrestrial (high duty factor) to aerial (low duty factor) running styles, which we metaphorically refer to as “grizzlies” and “gazelles,” respectively. Because the duty factor distinguishes running style, there are implications for the training regimens of grizzlies and gazelles in soccer, and exercises to improve performance should be developed based on the biomechanical advantages of each spontaneous running style.

Bissas, A, Paradisis, GP, Nicholson, G, Walker, J, Hanley, B, Havenetidis, K, and Cooke, CB. Development and maintenance of sprint training adaptations: an uphill-downhill study. J Strength Cond Res XX(X): 000-000, 2020-We examined the development of performance adaptations resulting from an uphill-downhill training program and monitored the decline of adaptations during detraining. Twenty-eight men were randomly assigned to 1 of 2 sprint training groups who trained 3 times per week for 6 weeks and a control group (C). The uphill-downhill group (U+D) trained on an 80-m platform with 3° slopes, whereas the horizontal (H) group trained on flat track. Subjects were tested for maximal running speed (MRS), associated kinematics, and leg strength before and after training, with U+D subjects also tested after weeks 2 and 4 of training, and after a 3-week detraining period. The U+D group increased their MRS by 3.7% (from 8.75 ± 0.72 to 9.07 ± 0.64 m·s, p < 0.05), their stride rate by 3.1% (from 4.21 ± 0.21 to 4.34 ± 0.18 Hz, p < 0.05), and their knee extensors' maximum isometric force by 21% (from 2,242 ± 489 to 2,712 ± 498 N, p < 0.05) after training. The time course of changes showed declines for weeks 1-4 (1.4-5.1%), but an ascending trend of improvement compensated all losses by the end of week 6 (p < 0.05). During detraining, no decreases occurred. No changes were observed for the H and C groups. The minimum period to produce positive effects was 6 weeks, with a very good standard of performance maintained 3 weeks after training. U+D training will prove useful for all athletes requiring fast adaptations, and it can fit into training mesocycles because of its low time demands.

INTRODUCTION: Distance runners train at different speeds to enhance their physiological and biomechanical capabilities to ensure that their aerobic and anaerobic energy systems are optimised for the demands of racing. The kinematic, kinetic, spatiotemporal, and global stiffness changes that occur as an athlete increases speed are not well understood in well-trained middle-distance runners. The aim of this study was to analyse the biomechanical responses of middle-distance athletes to increases in treadmill speed. METHODS: Thirteen male athletes (1.79 ± 0.07 m, 66.7 ± 6.1 kg, 22.3 ± 3.2 y) and two female athletes (stature: 1.69 ± 0.01 m, mass: 55.7 ± 0.4 kg, 30.9 ± 2.6 y) participated. Their mean World Athletics points for personal best performances were 1114 (± 73). Each athlete ran on a Gaitway 3D instrumented treadmill (1000 Hz) during an incremental test at 12, 16, 20 and 24 km/h. Data were collected during the second half of each 1-min stage. Two Fastec T5 high-speed cameras (200 Hz) were placed to the sides of the treadmill to record each side of the body separately, and the starting times were synchronised with the treadmill’s data collection period. Ground reaction force (GRF) and spatiotemporal data were measured using the treadmill software; lower limb joint angles were measured using the high-speed videos in SIMI Motion; and global stiffness characteristics were calculated using peak vertical GRF via the methods of Morin et al. (JAB, 2005, 21(2), 167–180). RESULTS: Both step length and cadence increased at each faster running speed (from 1.24 m and 2.70 Hz at 12 km/h to 2.01 m and 3.32 Hz at 24 km/h). Ground contact time decreased during each stage (0.229, 0.194, 0.168 and 0.147 s, respectively), but flight time only increased until 20 km/h (0.143, 0.160 and 0.163 s), with lower values at 24 km/h (0.155 s). Duty factor decreased during each stage (0.308, 0.274, 0.254 and 0.244, respectively) although leg stiffness was consistent throughout testing (11.4, 11.4, 11.4 and 11.6 N/mm, respectively). Vertical push-off rate increased consistently during each stage (31.6, 41.4, 51.2 and 59.9 BW/s, respectively). The main changes that occurred in joint angles and positions at initial contact were an increase in thigh angle (21, 25, 28 and 29°, respectively), shank angle (3, 5, 7 and 8°, respectively) and hip-ankle horizontal distance (0.18, 0.22, 0.25 and 0.27 m, respectively). CONCLUSION: It was unsurprising that athletes increased step length and cadence with faster treadmill belt speeds, although the increase in cadence from 20 to 24 km/h was the only one that arose from both shorter contact and flight times. The lack of reliance on increased flight time, and the very small increases in joint angles and positions from 20 to 24 km/h, show that there is an anthropometric limit on achieving faster speeds, which require greater force production during the push-off phase. Athletes should thus note the need for appropriate strength and conditioning within their training regimens.

The aim was to investigate the kinematic factors associated with successful performance in the initial acceleration phase of a sprint in the best male athletes in the World at the 2018 World Indoor Athletics Championships. High speed video (150 Hz) was captured for eight sprinters in the men's 60 m final. Spatio-temporal and joint kinematic variables were calculated from the set position to the end of the first ground contact post-block exit (GC1). Normalised average horizontal external power (NAHEP) defined performance and was the dependent variable for a series of regression analyses. Clear relationships were found between GC1 NAHEP and 10-m time, 60-m time, change in velocity, acceleration and contact time in the first ground contact (r = –0.74, –0.64, 0.96, 0.91 and –0.56, respectively). Stepwise multiple linear regression of joint kinematic variables in the first ground contact revealed that trunk angle at take-off and thigh separation angle at take-off explained nearly 90% of variation in GC1 NAHEP (R

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We evaluated sprint mechanical asymmetry in world-class competitors and evaluate whether interlimb sex-based differences in sprinting mechanics exist. The eight finalists in the men’s and women’s 100 m events at the 2017 IAAF World Championships were studied. Five high-speed cameras (150 Hz) were used to capture two consecutive steps of the whole body between 47.0 m and 55.5 m from the start, while four additional cameras (250 Hz) focussed on the lower extremities. A total of 33 spatio-temporal, touchdown and toe-off joint angles, and horizontal and vertical foot velocity parameters were extracted through three-dimensional analysis. Group mean asymmetry scores were assessed using the symmetry angle (SA) where scores of 0% and 100% represent perfect symmetry and perfect asymmetry, respectively. Although considered generally low (SA < 3% for 22 out of 33 parameters), the magnitude of mechanical asymmetry varied widely between sprinters of the same sex. However, there was no mean SA scores difference between men and women for any stride mechanical parameters (all P≥0.064). Asymmetry scores were inconsistent between parameters and phases (touchdown vs toe-off instants), and sprinting mechanics were generally not related to asymmetry magnitudes. In summary, low to moderate asymmetry is a natural phenomenon in elite sprinting. Asymmetry was inconsistent between parameters and competitors during near maximum-velocity running, yet mean values for a given parameter generally did not differ between sexes. Sprinters’ performances were not related to their SA scores.

INTRODUCTION: Markerless motion capture (MMC) is increasing in popularity among biomechanists because of the reduced data collection time and removal of subjects needing to wear tight, minimalist clothing [1]. However, gait analysis often requires subjects to walk or run at multiple speeds, such as in an incremental exercise test. The sensitivity of MMC to detect kinematic changes across speeds has yet to be thoroughly explored, so the aim of this study was to compare kinematic responses to changes in gait speed when measured with a widely used marker-based system versus a MMC system. METHOD: Fifteen healthy, adult participants walked on an instrumented treadmill (1,000 Hz; Gaitway3D; h/p/cosmos) at 3 and 5 km/h and ran at 10, 11, and 12 km/h. A 14-camera optoelectronic motion capture system (Oqus 7+, Qualisys) was used to collect marker data, where markers were placed according to Cappozzo et al. [2]. Markerless video data were collected synchronously with 12 high-speed video cameras (Miqus, Qualisys). Both systems were sampling at 100 Hz. Markerless data were exported to Theia3D for processing, before being exported to Visual3D for modelling alongside marker data. Gait events were determined using the kinetic data, which was the same for both motion capture systems. Kinematic data were exported to MATLAB to calculate changes in sagittal angular data between gait speeds. RESULTS: For walking (changes between 3-5 km/h), MMC demonstrated the capacity to measure similar changes in joint range of motion (ROM), peak flexion, and peak extension for hip, knee, and ankle joints (ICC[3,1] ≥ 0.892) when compared to marker-based data, and there were no significant differences between the change in joint kinematics between systems (p > 0.05). MMC also displayed moderate-to-excellent agreement for knee and ankle joint kinematics during running (changes between 10-11 and 11-12 km/h), including ROM and peak flexion/extension (ICC ≥ 0.626). However, the hip joint was less consistent, with poor-to-moderate agreement generally being found, especially in peak hip extension (ICC = 0.198 when comparing differences between 11-12 km/h). There were no significant differences between systems during running (p < 0.05). CONCLUSION: MMC was able to measure small changes in joint angles during walking at similar magnitudes to traditional marker-based motion capture, which is promising for clinical biomechanists and gait analysis clinics. However, MMC importantly performs less well when trying to measure joint angle changes during different running speeds, with varying results between lower limb joints. Researchers and practitioners should be cautious when interpreting sagittal-plane kinematic changes during running when employing MMC as the chosen method of motion capture. REFERENCES: [1] Kanko, RM et al. (2021) J Biomech;127:110665 [2] Cappozzo, A et al. (1995) Clin Biomech;10:171-8