Ben Nicholson

Within the football codes, sprint performance is considered an important capacity for success and is therefore targeted as an area of athletic development programmes. However, the concurrent and complex nature of physical preparation for the football codes presents several challenges for effective sprint development. This thesis aimed to evaluate and enhance the understanding of the development of sprint performance in football code athletes to support the delivery of best practices. This thesis is comprised of sequential sections presented through a series of chapters. First, systematic reviews with meta-analyses to evaluate the evidence base for the development of sprint performance (short- and medium-long distances). Second, a practitioner survey analysing the applied training practices and justifications for the organisation and evaluation of the sprint development. The last section provides observations and evaluation of profiling methods for phase and distance-specific sprint performance using a case study of combined training methodologies in elite male youth rugby league athletes. The systematic review and meta-analysis showed sport-only training and short sprints with incomplete rest appear to be insufficient to enhance sprint performance in football code athletes. Instead, sprint development requires either or preferably a combined method approach to both improving sprinting skills (i.e., sprints performed with overload (physical or co-coordinative)) and the athlete's physical characteristics (i.e., plyometrics and resistance training). Combined with the surveys and case studies this research showed that a one size fits all approach to sprint development (i.e., exercises, loading ect.) is not applicable; instead, effective training strategies depend upon the individuals and context that it is applied. Therefore, the content of the training (e.g., training frequency, exercise selection, training load prescription) is highly variable in research and practice, but so is the training response. Applying frequent and embedded monitoring of key variables (i.e., mechanical profiling) can support personalised and potentially improved training practices. Sprint development in football code practice is challenging (particularly long-term) due to the complexity and at times, competing requirements of an athlete’s development. Therefore, if an individual or team of football code athletes aims to enhance sprint performance, it requires prioritisation from all the key stakeholders.

Purpose: The aim of this study was to investigate the associations between matched mechanical variables derived from both vertical and horizontal force-velocity-power (FVP) profiling, and the performance outcome variables within squat jump (SJ) and sprint performance. Methods: 20 elite male academy rugby league players (age 17.6±0.9 years; height 179.9±6.6cm; body mass 91.2±11.8kg) performed two maximal 40m sprints. The sprints were recorded using a radar gun device (Stalker ATS II, Applied Concepts, Dallas, TX, USA), which obtained instantaneous speed-time measurements. In addition, the participants performed two maximal SJ (∼90◦ knee angle) repetitions with these loads: 0kg, 20kg, 40kg, 60kg and 80kg. An Optojump (OptoJump Next Microgate, Bolzano, Italy) was used to record the SJ’s, which provided jump height (cm) for each load. Body mass relative vertical and horizontal mechanical variables (theoretical maximal values of force (F0) (N/kg), velocity (V0) (m/s), power (Pmax) (W/kg)) and the slope of the F-V linear relationship (Sfv) were calculated. Sprint performance was determined from the modelled velocity-time data (2m,5m,10m,20m sprint time (s) and Vmax (m/s). Pearson’s correlation coefficients (r) assessed the relationship between matched vertical and horizontal mechanical variables (F0 vertical & horizontal, v0 vertical & horizontal, Pmax vertical & horizontal and Sfv vertical & horizontal) and SJ and sprint performance. Results: Table 1. shows the correlations coefficient between the sprint and SJ force-velocity profiles and performance variables. There was no significant correlation between vertical and horizontal FVP matched mechanical variables (p > 0.05). The correlations between vertical FVP variables and sprint performance and between horizontal FVP variables and SJ performance failed to reach statistical significance (p > 0.05). Moderate -0.32 to near perfect 1.0 significant correlations (p < 0.05) were found between mechanical and performance variables shifting the importance of separate variables depending on the testing task. Conclusions: The absence of significant correlations between the vertical and horizontal FVP profiles suggests that they provide distinctive information about the athlete’s mechanical variables. The magnitude of the correlations between mechanical variables and sprint performance shifted across the velocity-time curve, therefore performance is determined by separate qualities depending on the distance. Whereas, Pmax reported the greatest correlation with SJ height. Practical Application: To ensure specific, accurate and comprehensive characterisation of athletes’ physical qualities FVP profiles should be determined with exercises maximal mechanically similarity to the targeted performance task. These results will aid practitioners in test selection the prescription and individualisation of training by providing important information as to the most influential variables to develop SJ and sprint performance.

Background Short-sprint (≤20m) performance is an important quality for success in the football codes. Therefore, developing an evidence base for understanding training methods to enhance short-sprint performance is key for practitioners. However, current systematic reviews are limited by 1) a lack of focus on football code athletes, 2) a lack of consideration of all training modalities, and 3) a failure to account for the normal training practices undertaken by intervention groups within their analysis. Therefore, this review aimed to 1) conduct a systematic review of the scientific literature evaluating training interventions upon short-sprint performance within football code athletes, 2) undertake a meta-analysis to assess the magnitude of change of sport-sprint performance following training interventions, and 3) identify how moderator variables affect the training response. Methods A systematic search of electronic databases was conducted. A random-effects meta-analysis was performed to establish standardised mean difference with 95% confidence intervals. This identified the magnitude and direction of the individual training effects of intervention subgroups (primary, secondary, combined-specific, tertiary and combined training methods) on short-sprint performance while considering moderator variables (i.e., football code, sex, age, playing standard, phase of season). Results 121 studies met the inclusion criteria, totalling 3,419 athletes. Significant improvements (small-large) were found between pre- and post-training in short-sprint performance for the combined, secondary, tertiary and combined-specific training methods. No significant effect was found for primary or sport only training. No individual mode was found to be the most effective. Between-subgroup analysis identified that football code, age, playing standard and phase of season all moderated the overall magnitude of training effects. Conclusions This review provides the largest systematic review and meta-analysis of short-sprint performance development methods and the only one to assess football code athletes exclusively. Practitioners can apply combined, secondary and tertiary training methods to improve short-sprint performance within football code athletes. The application of sport only and primary methods does not appear to improve short-sprint performance. Regardless of the population characteristics, short-sprint performance can be enhanced by increasing either or both the magnitude and the orientation of force an athlete can generate in the sprinting action.

Background Within the football codes, medium-distance (i.e., > 20 m and ≤ 40 m) and long-distance (i.e., > 40 m) sprint performance and maximum velocity sprinting are important capacities for success. Despite this, no research has identified the most effective training methods for enhancing medium- to long-distance sprint outcomes. Objectives This systematic review with meta-analysis aimed to (1) analyse the ability of different methods to enhance medium- to long-distance sprint performance outcomes (0–30 m, 0 to > 30 m, and the maximum sprinting velocity phase [Vmax]) within football code athletes and (2) identify how moderator variables (i.e., football code, sex, age, playing standard, phase of season) affected the training response. Methods We conducted a systematic search of electronic databases and performed a random-effects meta-analysis (within-group changes and pairwise between-group differences) to establish standardised mean differences (SMDs) with 95% confidence intervals and 95% prediction intervals. This identified the magnitude and direction of the individual training effects of intervention subgroups (sport only; primary, secondary, tertiary, and combined training methods) on medium- to long-distance sprint performance while considering moderator variables. Results In total, 60 studies met the inclusion criteria (26 with a sport-only control group), totalling 111 intervention groups and 1500 athletes. The within-group changes design reported significant performance improvements (small–moderate) between pre- and post-training for the combined, secondary (0–30 and 0 to > 30 m), and tertiary training methods (0–30 m). A significant moderate improvement was found in the Vmax phase performance only for tertiary training methods, with no significant effect found for sport only or primary training methods. The pairwise between-group differences design (experimental vs. control) reported favourable performance improvements (large SMD) for the combined (0 to > 30 m), primary (Vmax phase), secondary (0–30 m), and tertiary methods (all outcomes) when compared with the sport-only control groups. Subgroup analysis showed that the significant differences between the meta-analysis designs consistently demonstrated a larger effect in the pairwise between-group differences than the within-group change. No individual training mode was found to be the most effective. Subgroup analysis identified that football code, age, and phase of season moderated the overall magnitude of training effects. Conclusions This review provides the first systematic review and meta-analysis of all sprint performance development methods exclusively in football code athletes. Secondary, tertiary, and combined training methods appeared to improve medium-long sprint performance of football code athletes. Tertiary training methods should be implemented to enhance Vmax phase performance. Nether sport-only nor primary training methods appeared to enhance medium to long sprint performance. Performance changes may be attributed to either adaptations specific to the acceleration or Vmax phases, or both, but not exclusively Vmax. Regardless of the population characteristics, sprint performance can be enhanced by increasing either the magnitude or the orientation of force an athlete can generate in the sprinting action, or both.

This cross-sectional study evaluated the sprint and jump mechanical profiles of male academy rugby league players, the differences between positions, and the associations between mechanical profiles and sprint performance. Twenty academy rugby league players performed 40-m sprints and squat jumps at increasing loads (0-80 kg) to determine individual mechanical (force-velocity-power) and performance variables. The mechanical variables (absolute and relative theoretical maximal force-velocity-power, force-velocity linear relationship, and mechanical efficiency) were determined from the mechanical profiles. Forwards had significantly (p < 0.05) greater vertical and horizontal force, momentum but jumped lower (unloaded) and were slower than backs. No athlete presented an optimal jump profile. No associations were found between jump and sprint mechanical variables. Absolute theoretical maximal vertical force significantly (p < 0.05) correlated (r = 0.71-0.77) with sprint momentum. Moderate (r = -0.47) to near-perfect (r = 1.00) significant associations (p < 0.05) were found between sprint mechanical and performance variables. The largest associations shifted from maximum relative horizontal force-power generation and application to maximum velocity capabilities and force application at high velocities as distance increased. The jump and sprint mechanical profiles appear to provide distinctive and highly variable information about academy rugby league players' sprint and jump capacities. Associations between mechanical variables and sprint performance suggest horizontal and vertical profiles differ and should be trained accordingly.

Background Motor competence is an integral component of the health and performance of youth. Numerous studies support the hypothesis that motor competence interacts with perceived motor competence and physical fitness during childhood to induce positive (e.g. healthy weight status) or negative (e.g. reduced physical activity engagement) trajectories. Yet, while adolescence is a key period of rapid growth and maturation, no systematic reviews and meta-analyses have examined the association between motor competence and physical activity, physical fitness and psychosocial characteristics solely within adolescents. Objectives This study aimed to (1) analyse the scientific literature evaluating associations between motor competence and physical activity, physical fitness and/or psychosocial characteristics amongst adolescents; (2) evaluate the associations between motor competence and physical activity, physical fitness characteristics and/or psychosocial characteristics amongst adolescents; and (3) investigate the impact of moderator variables (i.e., age, sex, type of motor competence assessment) on the associations. Methods A systematic search of electronic databases was conducted, followed by a qualitative synthesis of study methods. Random-effects meta-analyses were performed to establish the magnitude and orientation of pooled correlation coefficients between motor competence and physical activity, physical fitness and psychosocial characteristics of adolescents, whilst considering potential moderators (i.e., age, sex, type of motor competence assessment). Results Sixty-one studies were included, totalling 22,256 adolescents. Twenty-seven different assessments of motor competence were used, with 31 studies utilising product-orientated (i.e. outcome) motor competence assessments. Meta-analyses of 43 studies showed that motor competence was positively associated with physical activity (r = 0.20 to 0.26), some physical fitness characteristics (e.g. muscular strength, cardiovascular endurance; r = 0.03 to 0.60) and psychosocial characteristics (r = 0.07 to 0.34), and inversely associated with weight status (r =  − 0.36 to − 0.10), speed (r =  − 0.31) and agility (r =  − 0.37 to 0.41). Associations with flexibility were unclear. Conclusions The results of this systematic review and meta-analysis support the hypothesised interactions of motor competence with physical activity (positive), physical fitness (positive except for weight status, speed and agility) and psychosocial characteristics (positive) in adolescence. However, methodological approaches vary considerably (e.g. variety of motor competence assessments utilised), with limitations of the current literature including an inadequate assessment of motor competence, a lack of longitudinal observations and a failure to account for biological maturation. Future research assessing associations between motor competence and physical activity, physical fitness and psychosocial characteristics of adolescents should include longitudinal observations of a combined motor competence assessment (i.e. process and product) and account for biological maturation. Improved evaluation using these recommendations could provide more accurate data, leading to more targeted interventions to improve adolescents’ physical and psychosocial outcomes.

Female sports have recently seen a dramatic rise in participation and professionalism world-wide. Despite progress, the infrastructure and general sport science provisions in many female sports are behind their male counterparts. From a performance perspective, marked differences in physical and physiological characteristics can be seen between the sexes. Although physical preparation practices for male athletes are known, there are currently no published literature pertaining exclusively to female athletes. This information would provide invaluable data for both the researcher and practitioner alike. This survey therefore aimed to examine current practices utilized in female rugby codes (union, league, and sevens). A questionnaire assessing seasonal physical preparation practices, recovery, monitoring and sport science technology, and unique aspects in female rugby was developed. Thirty-seven physical preparation practitioners (32 males, 5 females) responded to the questionnaire. Most participants (78%) worked with national or regional/state level female athletes. Performance testing was more frequently assessed in the pre- (97%) and in-season (86%), than off-season (23%). Resistance, cardiovascular, sprint and plyometric training, and recovery sessions were all believed to be important to enhancing performance and implemented by most participants (≥ 89%). Sport science technologies were commonly (54%) utilized to inform current practice. Menstrual cycle phase was monitored by 22% of practitioners. The most frequently reported unique considerations in female rugby codes included psycho-social aspects (41%), the menstrual cycle (22%), and physical differences (22%). Practitioners working with female rugby can use the presented data to inform and develop current practices.

Background Motor competence is an integral component of the health and performance of youth. Numerous studies support the hypothesis that motor competence interacts with perceived motor competence and physical fitness during childhood to induce positive (e.g. healthy weight status) or negative (e.g. reduced physical activity engagement) trajectories. Yet, while adolescence is a key period of rapid growth and maturation, no systematic reviews and meta-analyses have examined the association between motor competence and physical activity, physical fitness and psychosocial characteristics solely within adolescents. Objectives This study aimed to (1) analyse the scientific literature evaluating associations between motor competence and physical activity, physical fitness and/or psychosocial characteristics amongst adolescents; (2) evaluate the associations between motor competence and physical activity, physical fitness characteristics and/or psychosocial characteristics amongst adolescents; and (3) investigate the impact of moderator variables (i.e., age, sex, type of motor competence assessment) on the associations. Methods A systematic search of electronic databases was conducted, followed by a qualitative synthesis of study methods. Random-effects meta-analyses were performed to establish the magnitude and orientation of pooled correlation coefficients between motor competence and physical activity, physical fitness and psychosocial characteristics of adolescents, whilst considering potential moderators (i.e., age, sex, type of motor competence assessment). Results Sixty-one studies were included, totalling 22,256 adolescents. Twenty-seven different assessments of motor competence were used, with 31 studies utilising product-orientated (i.e. outcome) motor competence assessments. Meta-analyses of 43 studies showed that motor competence was positively associated with physical activity (r = 0.20 to 0.26), some physical fitness characteristics (e.g. muscular strength, cardiovascular endurance; r = 0.03 to 0.60) and psychosocial characteristics (r = 0.07 to 0.34), and inversely associated with weight status (r =  − 0.36 to − 0.10), speed (r =  − 0.31) and agility (r =  − 0.37 to 0.41). Associations with flexibility were unclear. Conclusions The results of this systematic review and meta-analysis support the hypothesised interactions of motor competence with physical activity (positive), physical fitness (positive except for weight status, speed and agility) and psychosocial characteristics (positive) in adolescence. However, methodological approaches vary considerably (e.g. variety of motor competence assessments utilised), with limitations of the current literature including an inadequate assessment of motor competence, a lack of longitudinal observations and a failure to account for biological maturation. Future research assessing associations between motor competence and physical activity, physical fitness and psychosocial characteristics of adolescents should include longitudinal observations of a combined motor competence assessment (i.e. process and product) and account for biological maturation. Improved evaluation using these recommendations could provide more accurate data, leading to more targeted interventions to improve adolescents’ physical and psychosocial outcomes.

Despite the importance and complexity of developing sprint performance in football code athletes, there are limited studies exploring practitioners’ practices to improve sprinting. Therefore, this study aimed to describe and evaluate the practices used with elite football code athletes to develop sprint performance. Ninety subjects completed a survey comprised of four sections (coaching demographic, evaluation of training, organisation of training, and training protocols). Survey responses showed that 98% of practitioners monitor sprint performance, and 92% integrated monitoring strategies into sprint development programmes to inform training. All practitioners used combined training methods including specific (e.g., sprints with or without overload) and non-specific (e.g., strength training or plyometrics) methods targeting the underpinning determinants of sprint performance. Most practitioners reported prescribing 1-3 or 2-4 days·wk-1 for sprint development, both in-season and pre-season. Sprint development programmes were uncommon in the off-season. Most specific sprint training sessions were reportedly shorter in duration (5-15 and 15-30 min) than non-specific sprint training methods (30-45 and >45 min) irrespective of the season phases. Sprint development was integrated before and after sport-specific training, regularly using warm-ups and gym sessions. Specific training methods were also implemented in separate sessions. The specific content (e.g., exercise selection, training load prescription) was highly variable between practitioners. This study represents the first detailed survey (practices and justification) of sprint development practices (evaluation and organisation of training protocols) in football code cohorts. These findings present multiple methods of structuring, integrating and manipulating sprint training based on the training aims and the individual context.