Dr Chris Low

The purpose of this review was to systematically assess literature on differences between males and females in the physiological and biomechanical responses to load carriage during walking. PubMed, CINAHL, Scopus, Web of Science and the Cochrane library were searched. A total of 4637 records were identified and screened. Thirty-three papers were included in the review. Participant characteristics, load carriage conditions, study protocol, outcome measures and main findings were extracted and qualitatively synthesised. Absolute oxygen uptake and minute ventilation were consistently greater in males but there were limited sex-specific differences when these were expressed relative to physical characteristics. There is limited evidence of sex-specific differences in spatio-temporal variables, ground reaction forces (normalised to body mass) or sagittal plane joint angles with load. However, differences have been found in hip and pelvic motions in the frontal and horizontal planes, which might partly explain an economical advantage for females proposed by some authors.

This chapter explores the implementation and review of an assessment for learning (AfL) strategy in an undergraduate sport coaching degree, in the UK. After introducing the context of the degree – the framework around which it is built and the AfL strategy we developed – the chapter focusses on the implementation of the strategy in a Level 6 (final year) module. We explain the main theoretical ideas informing our approach and our expectations about the intended outcomes for student learning. Taking a practitioner research approach, we then review the AfL ‘experiment’, drawing on staff diaries and staff and student focus groups to reflect both on the successes of the approach and the difficulties we encountered across the year. We found that the AfL experiment worked well with students who attended, engaged, and had good existing self-regulatory skills and capacities. We also experienced several challenges with the wider body of learners who struggled with the consistent demand to produce and review work and with the social dynamics of peer feedback processes. We conclude with some ideas for the ongoing development and refinement of our AfL strategy in the hope that others may learn from our errors.

Instep kick research has shown that skilled soccer players display natural variations in their technique from trial-to-trial (Egan et al., 2007; Lees & Barton, 2005; Lees & Rahnama, 2013). This inherent movement variability (MV) has been described as a demonstration of ‘motor equivalence’, which has been defined as the ability to achieve an invariant end using variable means (Abbs & Cole, 1987). This movement strategy would benefit a soccer player by facilitating a consistent (stable) performance outcome whilst utilising a flexible range of solutions to adapt to different constraints. ‘Motor equivalence’ is closely associated with the concept of synergies, which can be identified and quantified using a motor control tool called the ‘uncontrolled manifold’ (UCM). The theoretical appeal of the UCM as an analysis tool has also been identified, but not implemented in recent sports biomechanics studies (Carson et al., 2014a; Carson et al., 2014b). Therefore, the UCM method was used as vehicle for evaluating MV structure and ‘motor equivalence’ within a sport-specific task, and to determine whether the UCM method could provide a better understanding of instep soccer kick technique and performance in comparison to a traditional biomechanics approach.  Twelve male university soccer players (age 20.8  ±  2.7 years, height 1.80  ±  0.03 m and mass 79.6  ±  6.2 kg) who were right foot dominant participated in this project and were instructed to perform a maximal instep kick at a 1m2 target at a distance of 11m. Three-dimensional kinematic data was recorded from a motion analysis system using a 15-segment whole-body model to compute kinematic variables for the traditional biomechanical analysis. For the UCM analysis, trial-to-trial variations of seven joint angles of the kicking leg, and principal components of the whole-body, were analysed across the normalised whole movement trajectory to investigate the MV structure of eight hypothesised performance variables. The dependent measures were UCM variability measures and strength of synergy. The main findings from the research project were:  Selected technique, performance and task variables produced values consistent with instep kicking literature. There was no clear differences between hit and missed kicks across all biomechanical variables. The UCM analysis across all participants revealed that eight hypothesised performance variables produced synergies, across all time periods of the instep kick. This finding provided empirical evidence to support the demonstration of ‘motor equivalence’ in instep soccer kicking technique.  Clear differences were noted between hit and missed kicks base on the UCM analysis. Missed kicks were characterised as producing lower strength of synergies, higher ranges of solutions, higher total variability and less stability across all performance variables for all time periods of the instep kick. A case study analysis showed clear differences between hit and missed kicks and highlighted unique differences in comparison to the group UCM analysis.  A comparison between UCM variables and instep kick task variables did not reveal any clear relationship between these different outcomes, which were attributed to the kicking task constraints used for this project.  This current project provided an original contribution to contemporary understanding of a complex technique through an evaluation of instep soccer kicking and MV structure.

It has been suggested that freedom of movement in the trunk could influence load carriage economy. This study aimed to compare the economy and sagittal plane trunk movements associated with three load carriage methods that constrain posture differently. Eighteen females walked at 3 km.h-1 with loads of 0, 3, 6, 9, 12, 15 and 20 kg carried on the back, back/front and head. Load carriage economy was assessed using the Extra Load Index (ELI). Change in sagittal plane trunk forward lean and trunk angle excursion from unloaded to loaded walking were assessed. Results show no difference in economy between methods (p = 0.483), despite differences in the change in trunk forward lean (p = 0.001) and trunk angle excursion (p = 0.021) from unloaded to loaded walking. We conclude that economy is not different among the three methods of load carriage, despite significant differences in sagittal plane trunk movements.

The ethics and effectiveness of performance sport coaching has come under scrutiny in recent years with high-profile reviews of culture within medal winning Olympic sports, such as The Whyte Review in gymnastics. As part of policy responses, interventions involving the coaching workforce have been recognised but the majority of these could be perceived as actions to be done to coaches rather than mechanisms which are empathetic to the realities of performance coaches and support the avoidance of influences which may result in unethical, abusive practice emerging. There is a sense that the coach as a human within the system has been lost or forgotten. This study seeks to witness, give voice to, and represent the lived reality of performance coaches in artistic gymnastics, embracing the centrality of emotion within the social, relational process of coaching (Portrac et al., 2017; North, 2017). Arts-based approaches are increasingly promoted in the academy (Sparkes & Smith, 2014; Evans et al., 2021) recognising their power to precede the intellectual with more aesthetic ways of knowing (Leavy, 2019). Visual methods are a powerful and effective way to access, construct and convey the sensory, emotional, embodied aspects of everyday life (Sparkes & Smith, 2014; Rose, 2023; Pink, 2021) positively promoting critical reflection and potentially inspiring change in the audiences (Ward & Schortt, 2020). An ethnographic documentary photography methodology (Pink, 2021) has been used to produce researcher generated images that attempt to capture and evoke the affective qualities of the coach’s reality (Rose, 2023); moving beyond the descriptive to the interpretive (Pink, 2021; Rose, 2023). Although utilised within visual sociology for over sixty years (Harper, 2016), this methodology is atypical within sport coaching contexts, where visual methods have tended to be more aligned to photo-elicitation approaches (see Cope, Harvey & Kirk, 2015). An initial ‘sketchbook’ process combined narrative fieldwork descriptions and audio recorded conversations alongside the photographic images to facilitate construction and sense-making of narratives and connections (Pink, 2021; Sparkes & Smith, 2014). Coaches were invited to collaborate with the researcher to co-construct knowledge and insight of their everyday reality (Horsley, 2021) through a discussion of their interpretations of a selection of images (initially of their own, and subsequently of other coach’s, situated realities) (Pink 2021). This approach enabled a layered relational ethical approach to informed participant consent recognising the overt ethical challenges within visual methodologies (Pink, 2021). Study findings are presented as a gallery of photos outside of the oral presentation. In line with ‘The Letting Go Perspective’ in Sparkes & Smith (2014), the suggested criteria of Barone & Eisner (2012) are the proposed basis for critical judgement of the work. While we the researchers, feel the work meets this bar, it is the response, engagement and reflection of the viewers that is of relevance, and of interest to examine (Sparkes & Smith, 2014; Pink, 2021). To that end, we invite delegates to actively participate in a collaborative, critical dialogue, through direct written comments on the images themselves or via recorded discussion, of performance coaches lived realities. Barone, T., & Eisner, E. W. (2012) Arts Based Research. Los Angeles:SAGE Cope, E., Harvey, S., & Kirk, D. (2015). Reflections on using visual research methods in sports coaching. Qualitative Research in Sport, Exercise and Health, 7(1), 88-108. https://doi.org/10.1080/2159676X.2013.877959 Evans, A. B., Barker-Ruchti, N., Blackwell, J., Clay, G., Dowling, F., Frydendal, S., Hybholt, M. G., Hausken-Sutter., S. E., Lenneis, V., Malcolm, D., Phoenix, C., Smith, B., Nielsen, C. S., Wilcock, L., Williamsc, O., & Winther, H. (2021). Qualitative research in sports studies: challenges, possibilities and the current state of play. European Journal for Sport and Society, 18(1), 1-17. https://doi.org/10.1080/16138171.2021.1899969 Harper, D. (2016). The Development of Visual Sociology: A view from the inside. SocietàMutamentoPolitica, 7(14), 237–250. https://doi.org/10.13128/SMP-19704 Horsley K. (2021). Slowing down: documentary photography in early childhood. International Journal of Early Years Education, 29(4), 438-45. https://doi.org/10.1080/09669760.2020.1850430 Leavy, P. (2019) Introduction to arts-based research. In P. Leavy (Ed.), Handbook of Arts-Based Research (pp 3-21). New York: Guilford Press. North, J. (2017). Sport Coaching Research and Practice: Ontology, Interdisciplinarity and Critical Realism. London:Routledge. Pink, S. (2021). Doing Visual Ethnography. (4th ed.) London:SAGE Publications Ltd. Potrac, P., Smith, A., & Nelson, L. (2017). Emotions in sport coaching: an introductory essay. Sports Coaching Review, 6(2), 129-141. https://doi.org/10.1080/21640629.2017.1375187 Rose G. (2023). Visual methodologies: an introduction to researching with visual materials. (5th ed.) London; Thousand Oaks, CA:SAGE Publications Ltd. Sparkes, A. C., & Smith, B. (2014). Qualitative research methods in sport, exercise and health: From process to product. New York:Routledge/Taylor & Francis Group. Ward, J., & Shortt, H. (2020). Using arts-based methods of research: A critical introduction to the development of arts-based research. In J. Ward & H. Shortt (Eds.), Using Arts-Based Research Methods: Creative Approaches for Researching Business, Organisation and Humanities (pp. 1–13) Basingstoke: Palgrave Macmillan.

Little is known about the biomechanics of sprint canoeing, especially for women’s canoeing, and a quantitative kinematic description of the motion would help coaches to develop valid technique coaching models. Five highly-trained female canoeists were filmed at 150 Hz while undertaking a 50 s maximal effort on a canoe ergometer, whose trolley motions were taken to represent those of the boat. Selected boat, body and paddle kinematics were evaluated at three key stroke cycle events (Contact, Paddle Vertical, and End of Drive) and their patterns monitored across the stroke cycle. While no clear trends between the kinematics and power output emerged, a range of strategies were identified and the data represent an initial step in the construction of detailed technique models that can be used to evaluate and monitor individual athletes.

The determinants of energy saving phenomena reported for load carried on the head, back and in a doublepack remain unclear. This study compared the energetic, kinematic and kinetic responses to head (H), back (B) and doublepack (DP) loading. Fifteen volunteers walked on an instrumented treadmill at 3 km.h-1 with 0, 3, 12 and 20 kg in each loading method. Whole body motion, ground reaction forces (GRF) and metabolic cost were measured. H was less economical than B (p = 0.014) and DP (p = 0.010). H was also associated with increased step length (p = 0.045), decreased cadence (p = 0.001), greater trunk (p < 0.001) and hip (p < 0.001) extension and greater minimum vertical GRF (p = 0.001) than B and DP. In conclusion, no energy saving was found for head- or back-loading but economy may be improved with methods that cause smaller perturbations from unloaded walking. Practitioner summary: Energy saving phenomena have been reported for load carried on the head, back and in a doublepack, yet the determinants are unclear. This study shows that smaller perturbations from unloaded to loaded walking are associated with improved economy for certain load carriage conditions, such as the doublepack.

It is anticipated that women’s Canoe Sprint will be included in the Olympic programme in Tokyo in 2020. Although the discipline has been a part of the Men’s programme since 1948, little biomechanics-based research has taken place and coaches have limited scientific information to guide their technique analysis or coaching interventions. Therefore the purpose of this study was to quantitatively report kinematics of women’s sprint canoeing technique at different intensities to establish key aspects of the movement patterns that were similar across the group, and also those that differed between participants. Five highly-trained competitive female canoeists (age 21.6 ± 2.5 years; C1 200m personal best, 56 ± 6 s) (mean ± SD), who comprised two right-sided and three left-sided paddlers, participated in the institutional ethics approved study. Participants completed three randomised 30 s efforts at 60, 80 and 100% of the power output of a 50 s simulated 200m race effort on a canoeing-specific ergometer (WEBA sport, Austria). 3D kinematic data were collected using a methodology previously reported (Wainwright et al., 2016, Proceedings of ISBS Conference) using individualised inertia models (Yeadon, 1990, Journal of Biomechanics, 23, 67-74) within an inverse kinematics model in Visual3D. While many of the kinematics presented similar trends the movements of the pelvis relative to the boat, and trunk relative to the pelvis, demonstrated the largest variations within and between participants across the intensities. Pelvis and trunk flexion and extension were found to be coupled, as were pelvis and trunk internal and external rotation. During the drive phase the pelvis tilt decreased as the trunk increased flexion, while the pelvis and trunk rotated towards the stroke side. Pelvis rotation started after the trunk and was of a shorter duration. Differences were observed in the magnitudes of pelvis and trunk rotation and flexion, and timings of the segmental movements within and between participants across the intensities. Therefore each participant displayed subtle and consistent changes in their individualised movement patterns in response to the task demands. This study generated an appropriate methodology that successfully quantified the kinematics of the Canoe Sprint movement, and has demonstrated that a range of individualised strategies can be employed in response to changes in the task. Further research is required to understand the relationships between subtle within and between participant differences in pelvis-trunk co-ordination, on-water boat velocity and performance in order to provide coaches with an improved ability to enhance on-water performance.

Inspiratory muscle training (IMT) and functional IMT (IMTF: exercise-specific IMT activities) has been unsuccessful in reducing respiratory muscle fatigue following load carriage. IMTF did not include load carriage specific exercises. Fifteen participants split into two groups (training and control) walked 6 km loaded (18.2 kg) at speeds representing ∼50%V̇O2max in cold-hypoxia. The walk was completed at baseline; post 4 weeks IMT and 4 weeks IMTF (five exercises engaging core muscles, three involved load). The training group completed IMT and IMTF at a higher maximal inspiratory pressure (Pimax) than controls. Improvements in Pimax were greater in the training group post-IMT (20.4%, p = .025) and post-IMTF (29.1%, p = .050) compared to controls. Respiratory muscle fatigue was unchanged (p = .643). No other physiological or subjective measures were improved by IMT or IMTF. Both IMT and IMTF increased the strength of respiratory muscles pre-and-post a 6 km loaded walk in cold-hypoxia. Practitioner Summary: To explore the interaction between inspiratory muscle training (IMT), load carriage and environment, this study investigated 4 weeks IMT and 4 weeks functional IMT on respiratory muscle strength and fatigue. Functional IMT improved inspiratory muscle strength pre-and-post a loaded walk in cold-hypoxia but had no more effect than IMT alone. Abbreviations: ANOVA: analysis of variance; BF: breathing frequency; CON: control group; EELV: end-expiratory lung volume; EXP: experimental group; FEV1: forced expiratory volume in one second; FiO2: fraction of inspired oxygen; FVC: forced vital capacity; HR: heart rate; IMT: inspiratory muscle training; IMTF: functional inspiratory muscle training; Pemax: maximal expiratory pressure; Pimax: maximal inspiratory pressure; RMF: respiratory muscle fatigue; RPE: rate of perceived exertion; RWU: respiratory muscle warm-up; SaO2: arterial oxygen saturation; SpO2: peripheral oxygen saturation; V̇E: minute ventilation; V̇O2: rate of oxygen uptake.

Equivocal findings exist for the economy associated with load carried close to the body's centre of mass. Individual variation could explain some of the equivocal findings. This research aimed to examine the extent of individual variation in loaded walking economy. Eighteen females carried load on the back, head and split between the front and back. Individual variation in relative load carriage economy (ELI) was primarily assessed using standard deviation, coefficients of variation (CV) and intraclass correlation coefficients (ICC). There was large inter-individual variation in ELI values with highest mean CV's of 16%, 12% and 10% for head-, back- and combined front and back-loading. Mean ELI values were not significantly different between methods. The large amount of individual variation found here suggests future load carriage research should account for individual variation, particularly when considering sample size and when making inferences on the economy associated with different types of load carriage using group mean data.

The stimulus article, “Golf swing technician Jim Christine: Bridging the gap between the science of the golf swing and the art of golf coaching”, and the accompanying commentaries present some key issues in golf coaching, especially coach development, technology, coaching methods, and critical thinking. The first two commentaries provide insight about Jim Christine’s development as a coach. International golf coach Peter Green discusses the legendary John Jacobs, who Jim accepted an invitation from to shadow him at one of his golf schools; and John Stirling, who Jim had coaching from on his own golf game. PGA Master Professional Luther Blacklock discusses Alex Hay, who also coached Jim. Both Stirling and Hay were pioneers in the training programme of the Professional Golfers’ Association (PGA) of Great Britain and Ireland in which Jim became highly influential as an author of training resources and as a tutor. There are commentaries from three distinguished members of the PGA of America, the world’s largest working sports organisation: David Wright, John Callahan and Eric Alpenfels. John Callahan shares how he took up opportunities to shadow leading golf coaches such as TJ Tomasi, Craig Shankland and Paul Runyan during his PGA apprenticeship under Frank Cardi. Callahan advocates the use of launch monitors as a technological aid, more staunchly so than Jim Christine who is aware of the limitations in the algorithms involved in providing the output from a radar device like TrackMan for measuring impact factors. Chris Bertram refers to his own empirical research on the use of another technological aid, video feedback, to indicate that “just because technical information is readily available, it does not mean that more information is necessarily serving the interests of the student” (p. 37). Drawing on his doctoral research on operant conditioning, David Wright discusses backward chaining, which is one of the coaching methods used by Jim Christine. Eric Alpenfels discusses Jim’s use of coaching methods in terms of “focus of attention – internal/external swing cues” (p. 33). Researchers Thomas Hawkins et al., suggest that “[the clock analogy], one of Christine’s favoured coaching tools may result in performance and learning benefits [through external focus of attention] because it allows the body to organise movement better than it would if conscious control was either requested or triggered by an internally focused coaching instruction” (p. 35). In a similar vein, Nicky Lumb, a PGA coach “who specialises in golf practice management, skill development and peak performance” (p. 40), indicates that several of Jim’s coaching tools give the golfer an external focus of attention. There is overlap in what Nicky does with Edward Coughlan, a sports scientist whose “main job for players involves asking questions about how they practice, what they practice and inevitably, whether their practice transfers to the competition arena” (p. 42). While two PGA of Great Britain and Ireland professionals, Will Shaw and Gordon Morrison discuss some of Jim’s coaching methods from an Information-Processing perspective, a third one – Noel Rousseau – advocates an Ecological Dynamics/Constraints-led Approach. Rousseau presents the case that “Jim’s coaching methods are staunchly embedded in the Information Processing camp yet he simultaneously highlights some of the shortcoming of coaching this way” (p. 50), especially on the matter of sloping lies (p. 51). Jim describes himself as a “swing technician” (p. 17). Researchers Liam Thomas et al. discuss the notion of a ‘model golf swing’ or ‘technical blue print’ and highlight the challenge of distinguishing between ‘technical faults’ and “the inherent variability both within and between individuals in response to changes in constraints” (p. 54). Tour pro coach, Hugh Marr argues, “Every coach has a picture in their head of what a great swing looks like. It’s not the model that makes coaches great, it’s the understanding of what George Gankas calls ‘match-ups’ – if a player displays one particular swing characteristic, they need to match it with another swing characteristic that complements it” (p. 57). The final two commentaries, by research professor David Grecic and performance coach Jon Roy, both emphasize the development of critical thinking in coaches, with the latter arguing that “Jim’s critical faculties comprise dialectics, scepticism, and innovation” (p. 63).

The drag flick is important in field hockey as it gives a greater opportunity to score a goal at penalty corners than hitting does. However, there is a lack of scientific research conducted on this technique. The purpose of this research was therefore to undertake a technique analysis of the drag flick. Given the paucity of research 10 field hockey coaches were recruited to synthesise expert opinions using a consensus-based, modified three-stage Delphi poll, comprising initial interviews and subsequent questionnaires. 28 physical and technical attributes were agreed and informed the biomechanical analyses. The four corners of the goal were agreed as the preferential target areas along with ball accuracy as the overall performance criterion. Twelve mixed ability field hockey players (8 male and 4 female) (age 24.25 ± 4.83 years, height 1.75 ± 0.09 m and mass 77.29 ± 17.44 kg) were then recruited to perform 60 drag flick trials at a 1 m2 target positioned in a standard field hockey goal at a distance of 14.63 m. The trials were split into three conditions: Self-selected target area, performance criterion ball accuracy; self-selected target area, ball velocity; and prescribed target area, ball accuracy. Three-dimensional kinematic data was recorded from a motion analysis system using a 15-segment model to compute performance and technique variables. An analysis of the full time series of kinematic data was completed to determine the core movement strategy of the drag flick technique. The main findings showed that the task constraint of accuracy altered the kinematic sequencing of players from a throw like pattern to more of a push like pattern. The left and right hip and shoulder ab-/adduction and left and right elbow and wrist flex/-extension are the key joint angles which contribute to the core of the drag flick technique. A dimensional reduction technique (PCA) was then applied to the same data to decompose the complex, but highly redundant set of postures into a comprehensible number of uncorrelated variables. Each of these variables represented multisegmented movements, which could be visualized. The main findings were that the left and right flex-/extension of the wrists are key to drag flick technique, in addition to the lowering of the thorax. Also the lower body kinematics explain greater variance compared with the shoulder and elbow joints, as they dominate the principal components, accounting for most of the variance. Although further work is required, this research has enhanced the understanding of the technique of the field hockey drag flick, particularly with respect to the core movement strategy.

The purpose of this study was to examine the Rear foot elevated split squat (RFESS) five repetition maximum test as a valid and reliable field method for measuring unilateral leg strength symmetry. With institutional ethical approval, 26 subjects (age = 23.8 ±4.6 years, mass = 88.1 ±10.7kg, height = 1.79±0.1m) with a minimum two years strength and conditioning experience were recruited. Following a familiarisation, session subjects performed an incremental 5 repetition maximum (RM) protocol on both legs, on two occasions where 3D motion and force data were collected. excellent reliability was found (ICC = 0.93 CL 0.88-0.96) in the load achieved between tests (mean load =0.96 ±0.18 kg/kg). Moderate reliability of bar load symmetry was found between test and re-test conditions correlation (ICC = 0.73, 0.33-0.91) with no proportional bias between sessions. Validation of the exercise was measured using a Pearson correlation between asymmetries in vertical ground reaction forces of the lead foot and bar load. When all maximal trials, from both test conditions, were analysed, a most likely large positive correlation (0.57, 0.30 to 0.76) were found for mean lead foot vGRF. When a threshold level of load symmetry (96.54% - 103.46%) was applied, a most likely large positive correlation (r = 0.59, 0.14-0.84) between symmetry in lead foot vGRF was found in subjects who exceeded this limit. Findings of this study suggest the RFESS is a valid and reliable measure of unilateral leg strength symmetry. Practitioners are recommended to use this exercise to investigate the strength symmetry of athletes, but are guided to note that a threshold level of symmetry (96.54% - 103.46%) may be required to have been exceeded to indicate a true difference in vGRF production

BACKGROUND: While respiratory muscle fatigue is present following load carriage activity at sea level, the effect of environmental conditions on respiratory strength while undertaking load carriage is unknown. METHODS: The effect of thoracic load carriage during walks (5.5 km) in four environments [(thermo-neutral sea level (SL), −10°C (C), 4300 m (H) and 4300 m at −10°C (HC)] was evaluated on respiratory muscle fatigue. Ten subjects completed eight self-paced randomized treadmill walks comprising a variety of gradients, unloaded and loaded (18.2 kg), across the four environments. Respiratory muscle strength was measured via maximal inspiratory pressure (PImax) and expiratory pressure (PEmax) assessments. RESULTS: Submaximal walking in HC elicited respiratory muscle fatigue when compared to SL. Inspiratory muscle fatigue was independent of load. The relative change in PImax from baseline was significantly greater in HC compared to SL (9.6% vs. 1.3%). PEmax showed a significant reduction during HC (−22.3 cmH2O, −14.4%) when compared to the other three environments. CONCLUSION: These results highlight the need to focus on respiratory muscle strength in preparation for exercise in cold hypoxic conditions.

Objectives The aim of this study was to analyse the relationship between unilateral leg strength, associated asymmetries and the injuries suffered by sub-elite Rugby League (RL) players in one competitive season. Design A prospective cohort design was used. Method Unilateral leg strength was measured using the rear foot elevated split squat five repetition maximum test. Injuries were recorded using the Orchard classification system and were used to quantify relative risk (RR), mean severity, burden, player availability and survival time. Results No measures of leg strength were related to RR, relative leg strength was found to have a significant, but not meaningful correlation with total time lost to lower body injury, lower body injury burden and lower body injury survival time. Conclusions The data from the current study indicates a possible positive effect of increasing relative leg strength for injury outcomes in sub-elite RL players. This supports a heuristic that multi-joint lower body strength training for RL players has a potential dual effect of enhancing physical performance and reducing injury time loss, with minimal risk of harm.

The symposium will provide an overview of how a multi-disciplinary research team engaged in supporting the British Canoeing Women’s Sprint Canoe Coach around the technical aspects of the Sprint Canoe stroke. Within the 60 minute session, the presenters will discuss how a coach’s technical model for a skill can be captured, and used, to better inform quantitative analysis of athlete technique which in turn can be used to check and challenge the technical understanding of the coach. The development of a reciprocal relationship can provide coaches with meaningful, purposeful feedback on their own technical understanding and on their athlete’s level of technical skill development while producing impactful research driven by real world coaching issues. Reflections will be provided within the symposium around developing a relationship with the coach to better understand their technical knowledge needs, tailoring the feedback of technical information to the coach to reflect their learning preferences and how that knowledge can be used to inform their practice. The symposium will conclude with a proposed framework for researchers to use when working with coaches to better bridge the gap between researchers and practitioners to produce meaningful, informed research that has real world coaching impact and application.

Purpose The purpose of this experiment was to evaluate the effect of load carriage in a range of temperatures to establish the interaction between cold exposure, the magnitude of change from unloaded to loaded walking and gradient. Methods Eleven participants (19-27 years) provided written informed consent before performing six randomly ordered walking trials in six temperatures (20°C, 10°C, 5°C, 0°C, -5°C and -10°C). Trials involved two unloaded walking bouts before and after loaded walking (18.2 kg) at 4 km.hr⁻¹, on 0% and 10% gradients in 4 minute bouts. Results The change in absolute oxygen consumption (V̇O₂) from the first unloaded bout to loaded walking was similar across all six temperatures. When repeating the second unloaded bout, V̇O₂ at both -5°C and-10°C was greater compared to the first. At -10°C, V̇O₂ was increased from 1.60 ± 0.30 L.min⁻¹ to 1.89 ± 0.51 L.min⁻¹. Regardless of temperature, gradient had a greater effect on V̇O₂ and heart rate (HR) than backpack load. HR was unaffected by temperature. Stride length (SL) decreased with decreasing temperature but trunk forward lean was greater during cold exposure. Conclusion Decreased ambient temperature did not influence the magnitude of change in V̇O₂ from unloaded to loaded walking. However, in cold temperatures, V̇O₂ was significantly higher than in warm conditions. The increased V̇O₂ in colder temperatures at the same exercise intensity is predicted to ultimately lead to earlier onset of fatigue and cessation of exercise. These results highlight the need to consider both appropriate clothing and fitness during cold exposure.

A sprint kayaking specific deterministic model was used to identify key performance related technique factors using data from 12 international-level kayakers. There was large variability in the strength of the between-factor relationships across the group. The pull phase was split into 3 components with the 1st phase contributing the most to increases in boat velocity and the 3rd phase causing a decrease in velocity. The propulsive impulse had the largest influence on velocity, but the magnitude of the impact was moderated by blade slip. Large propulsive impulses in the 3rd phase of the pull were associated with larger decreases in velocity. The results show that the model can be used to identify key technique factors on an individual level, although the use of the model should be confirmed on additional kayakers before being used in an applied setting by practitioners.

The purpose of the study was to determine the unilateral nature of the rear foot elevated split squat (RFESS). Specifically, the production of force by the rear leg was examined to better understand its role, if any, toward successful completion of the exercise. Male volunteers were recruited, (n = 26, age = 23.8 ±4.6 years, mass = 88.1 ±10.7kg, height = 1.79±0.1m), who were recreationally trained and engaged in a structured strength and conditioning program including both bilateral and unilateral exercise and had at least two years supervised training experience. Subjects participated in an incremental five repetition maximum protocol, following familiarisation. Kinetic data was recorded via two independent force plates, one integral to the floor and the second mounted on top of solid weightlifting blocks. Kinematic data was captured through three-dimensional motion analysis. A total of 715 repetitions were analysed, the mean contribution of the lead foot to total vertical force production was 84.36 ±3.6%. An almost certainly small positive correlation (rho = 0.25, CI 0.18, 0.33), was found between percentage of force produced by the lead foot, with increasing exercise intensity. A most likely trivial, non-significant correlation (rho = -0.01, CI -0.09,0.06) with rear foot force production, representing the mass of the rear leg. Data from this study does not indicate that the rear foot contributes to the kinetic demands of the exercise and therefore suggests that the RFESS is a valid unilateral exercise.

Rugby League (RL) is an intermittent, collision, invasion game, played internationally at professional, semi-professional and amateur level. The physiological attributes required for RL performance include, aerobic and anaerobic power, speed, acceleration, momentum, change of direction speed (CODS), strength, power and technical skill. Professional clubs operating in the Super League, develop academy players, as a method of talent development. However, not all players make the transition to senior, professional status, frequently required to leave this environment and participate at the semi-professional level. This study sought to better understand the physiological differences between these two levels, affording a better understanding of the career transition faced by academy graduates. The variables of examination were unilateral leg strength, strength symmetry, linear and change of direction speed. It was hypothesised that there would be significant differences between all variables. Rugby league players (n = 50), recruited from three different clubs, were used to investigate the physiological differences in unilateral leg strength and speed, both linear and COD. Tests of unilateral leg strength (rear foot elevated split squat 5RM, Helme et al, ePUB) and speed (20m sprint, modified 5-0-5 test) were separated by 48 hours. A magnitude based decision approach was used to determine between group differences in all variables measured. Semi-professional players were significantly heavier (+7kg, p =0.03, possibly moderate difference) than academy players, but there was no difference in height. No significant differences between groups in unilateral leg strength, either in absolute load or relative to body mass, nor was there any difference in strength symmetry. Analysis of linear sprint speed identified no differences between academy and semi-professional players between 0 and 10m, of a 20m sprint, however, between 10and 20m academy players had a possibly moderately higher mean velocity (7.57m/s vs 7.7m/s, p =0.35). Despite the difference in body mass no significant differences in momentum was observed. There were no significant differences between either group for change of direction speed or change of direction deficit. Academy and Semi-professional players exhibit comparable qualities with respect to unilateral leg strength, speed and change of direction ability. Such findings suggest that a career transition from academy to semi-professional Rugby League is an appropriate step, from a physiological perspective. However anthropometrically, the differences in body mass between groups suggests that such progression may not be so advantageous. Whilst both groups have equitable abilities, semi-professional players can perform these tasks at a significantly larger body mass, which is beneficial in collision sports. It should be concluded then, that in the transition to exit academy rugby league environments players should be focused on a strategy to simultaneously develop speed and change of direction ability, whilst accumulating greater lean body mass.

The purpose of this study was to examine the validity and reliability of the Rear Foot Elevated Split Squat (RFESS) five repetition maximum (5RM) test as a field method for measuring unilateral leg strength symmetry. As a validated method of testing symmetry, the RFESS 5RM may be used by Strength and Conditioning coaches and sports medicine staff to measure the presence of imbalances with minimal equipment and time. 26 subjects (age = 23.8 ±4.6 years, mass = 88.1 ±10.7kg, height = 1.79±0.1m) with a minimum two years strength and conditioning experience were recruited. Following a familiarization session, subjects performed an incremental five repetition maximum (5RM) protocol on both legs, on two occasions where 3D motion and force data were collected. Moderate reliability of bar load symmetry was found between test and re-test conditions correlation (ICC = 0.73, 0.33-0.91) with no proportional bias between sessions. Validation of the exercise was analyzed using a correlation between asymmetries in mean set vertical ground reaction forces (vGRF) of the lead foot during the concentric phase, with bar load. When all maximal trials, from both test conditions, were analyzed, a most likely large positive correlation (0.57, 0.30 to 0.76) were found for mean set concentric lead foot vGRF. When a threshold level of load symmetry (96.54% - 103.46%) was applied, a most likely large positive correlation (r = 0.59, 0.14-0.84) between symmetry in lead foot vGRF was found in subjects who exceeded this limit. Conversely, analysis of subjects within the threshold produced unclear correlations. Findings of this study suggest the RFESS is a valid and reliable measure of unilateral leg strength symmetry. Practitioners are recommended to use this exercise to investigate the strength symmetry of athletes, but are guided to note that a threshold level of symmetry (96.54% - 103.46%) may be required to have been exceeded to indicate a true difference in vGRF production.

The rear foot elevated split squat (RFESS) is a multi-joint, unilateral resistance exercise, commonly used in strength and conditioning McCurdy (2017). McCurdy, Langford et al. (2004) and McCurdy and Langford (2005) have previously reported the RFESS as a reliable measure of unilateral leg strength (1RM ICC, 0.97- 0.99). To further enhance the proposed frequency of use and reliability as both a single and multiple repetition test of leg strength, it is pertinent to quantify the kinetic and kinematic characteristics of the exercise. No study, to date, has yet analysed the intra-set differences in kinetic and kinematic parameters, in a multi-repetition test of leg strength. The aim of this study was to firstly quantify the kinetic and kinematic characteristics of the RFESS 5RM test protocol. Secondly to profile the intra-set differences between repetitions. 26 volunteers were recruited, with institutional ethical approval (age = 23.8 ±4.6 years, mass = 88.1 ±10.7kg, height = 1.79±0.1m), all subjects were engaged in a structured strength and conditioning program. Participants were required to undergo an incremental loading test until maximal load was achieved. Kinetic data was collected from the front and rear foot through two independent Kistler 9827C force plates at 1000Hz (Kistler Group, Winterthur, Switzerland), as depicted in figure 1. Kinematic data was captured through Qualysis Track Manager System at 250Hz (Qualysis AB, Gothenburg, Sweden) using 10 cameras (six ceiling mounted and four, floor mounted).Data was exported to a bespoke R code for this project. Magnitude based inferences were made on intra-set differences between repetitions for each of the kinetic and kinematic variables. The mean load lifted was 84kg ±16.8kg (0.96 ±0.18 kg/kg). The mean vertical displacement of the bar was 0.38 ± 0.06m, mean concentric velocity was 0.32 ±0.05m/s and peak concentric velocity was 0.49 ±0.11m/s. The mean vertical ground reaction force (vGRF) of the lead foot was 1432.54±200.87N, (1.66 ±0.20BW). The lead foot produced 83.53±4.03% of total vGRF There were unclear differences in all kinetic variables between all repetitions, except for peak (vGRF) of the lead foot only (1.90±0.28BW) of Repetition 5, which was very likely larger. Repetitions 1 and 2 were likely to very likely to have higher mean concentric velocities (MCV) than repetitions 4 and 5. The RFESS 5RM produces mean and peak concentric vGRF of 1.66±0.20 BW and 1.84±0.24BW, which approximately equals the values reported by (Ebben and Jensen, 2002) for a bilateral squat. The inconsistent inferential findings across the set suggest that the final repetition may be different to repetitions 1-4, generating the highest peak force, largest vertical displacement and slowest MCV. Such findings indicate that repetition 5 represents the maximal effort of that set and the maximal protocol. The RFESS 5RM is valid and reliable method of measuring unilateral leg strength. A multi-repetition protocol can be used to determine maximal strength, yet intra-set differences may not exist prior to completion of the final repetition. Practitioners should consider this information when evaluating the efforts of athletes during this exercise.

Rugby League (RL) is an intermittent, high intensity, collision sport characterised by frequent accelerations and changes of direction (Gabbett et al., 2008). Leg strength has been associated with improved performance in both linear and change of direction speed (CODS) (Bret et al., 2002, Wisløff et al., 2004, Cronin and Hansen, 2005, McBride et al., 2009). Previous research has used bilateral methods of investigating this association, yet few studies have taken a unilateral approach to strength assessment. The aim of this study was to investigate the relationships between unilateral leg strength speed, momentum, change of direction speed and change of direction deficit, in RL players. Further understanding the interaction to different forms of strength and performance measures may better enable practitioners to prepare their athletes. It was hypothesized that increased leg strength would positive influence performance in sprint and CODS measures. With institutional ethical approval testing was conducted at the respective facilities of three participating Rugby League clubs (n = 50). Physiological testing was separated into two sessions the first being speed and change of direction assessment and the second collection of strength data. CODS was measured using the modified 5-0-5 test, speed was tested using a 20m linear sprint from a standing start. For both tests three trials were performed and the best result used for analysis. Unilateral leg strength was measured using the rear foot elevated split squat (RFESS) 5RM (Helme et al, under review). Strength data was calculated in both absolute and relative terms, linear speed was analysed at both 10m and 20m for time, mean velocity and mean momentum for each 10m section. CODS was analysed for time and also for change of direction deficit, (Nimphius et al., 2016). The mean absolute load achieved in the RFESS 5RM was 88.92 ±12.59kg, when expressed relative to body mass was 1.01 ±0.17kg/kg. Possibly to likely small negative associations were found to both change of direction times and change of direction deficits. Possibly small positive associations were observed between momentum and velocity, for the 10-20m section, but not for 0-10m. No correlations reached the alpha level of significance (p = <0.05) for absolute strength. A most likely or almost certain moderate negative relationship was found between CODS and relative leg strength (p= <0.05) and a likely moderate positive relationship to linear mean velocity between 10 and 20m. Almost certainly moderate (10-20m) or large (0-10m) negative relationships were observed with momentum in a linear sprint (p = >0.05). The data from this study suggests that absolute unilateral leg strength is not significantly related to sprinting or CODS performance. However, increasing relative unilateral leg strength is positively associated with increased change of direction speed and velocity, specifically between 10m and 20m. Furthermore, almost certainly large negative correlations were found between relative leg strength and momentum, which is at odds with the other findings of this study. Baker and Newton (2008) identified momentum as a significant contributor to performance in RL, particularly in winning collisions, which are in turn, essential for successful match outcomes. Practitioners may consider the use of relative unilateral leg strength to better understand the development of velocity and CODS in their athletes. This should be taken with caution though, as further investigation is required to better understand the interaction between relative strength and momentum.

The rear foot elevated split squat (RFESS) is a multi-joint, unilateral resistance exercise, commonly used in strength and conditioning (McCurdy, 2017). McCurdy, Langford et al. (2004) and McCurdy and Langford (2005) have previously reported the RFESS as a reliable measure of unilateral leg strength (1RM ICC, 0.97- 0.99). To further enhance the proposed frequency of use and reliability as both a single and multiple repetition test of leg strength, it is pertinent to quantify the kinetic and kinematic characteristics of the exercise. No study, to date, has yet analysed the intra-set differences in kinetic and kinematic parameters, in a multi-repetition test of leg strength. The aim of this study was to firstly quantify the kinetic and kinematic characteristics of the RFESS 5RM test protocol. Secondly to profile the intra-set differences between repetitions. METHODS 26 volunteers were recruited, with institutional ethical approval (age = 23.8 ±4.6 years, mass = 88.1 ±10.7kg, height = 1.79±0.1m), all subjects were engaged in a structured strength and conditioning program. Participants were required to undergo an incremental loading test until maximal load was achieved. Kinetic data was collected from the front and rear foot through two independent Kistler 9827C force plates at 1000Hz (Kistler Group, Winterthur, Switzerland), as depicted in figure 1. Kinematic data was captured through Qualysis Track Manager System at 250Hz (Qualysis AB, Gothenburg, Sweden) using 10 cameras (six ceiling mounted and four, floor mounted).Data was exported to a bespoke R code for this project. Magnitude based inferences were made on intra-set differences between repetitions for each of the kinetic and kinematic variables. RESULTS The mean load lifted was 84kg ±16.8kg (0.96 ±0.18 kg/kg). The mean vertical displacement of the bar was 0.38 ± 0.06m, mean concentric velocity was 0.32 ±0.05m/s and peak concentric velocity was 0.49 ±0.11m/s. The mean vertical ground reaction force (vGRF) of the lead foot was 1432.54±200.87N, (1.66 ±0.20BW). The lead foot produced 83.53±4.03% of total vGRF There were unclear differences in all kinetic variables between all repetitions, except for peak (vGRF) of the lead foot only (1.90±0.28BW) of Repetition 5, which was very likely larger. Repetitions 1 and 2 were likely to very likely to have higher mean concentric velocities (MCV) than repetitions 4 and 5. Figure 1: Data collection procedures for the RFESS 5RM protocol DISCUSSION The RFESS 5RM produces mean and peak concentric vGRF of 1.66±0.20 BW and 1.84±0.24BW, which approximately equals the values reported by (Ebben and Jensen, 2002) for a bilateral squat. The inconsistent inferential findings across the set suggest that the final repetition may be different to repetitions 1-4, generating the highest peak force, largest vertical displacement and slowest MCV. Such findings indicate that repetition 5 represents the maximal effort of that set and the maximal protocol. CONCLUSION The RFESS 5RM is valid and reliable method of measuring unilateral leg strength. A multi-repetition protocol can be used to determine maximal strength, yet intra-set differences may not exist prior to completion of the final repetition

Objective The aim of this review was to synthesize the current understanding relating to the risks of lower body functional asymmetry with injury in athletic populations. Methods An iterative data mining and sampling approach was used to construct a search phrase from key words, which were used to identify studies within SPORTdiscus, Medline and Academic Search Complete databases. Additional references were sourced from the reference lists of these articles Results After screening, 31 papers were reviewed, from an initial search identifying 302 possible studies. A total of 6228 participants were involved in the studies, of which soccer players were the most observed sporting demographic (n =2171). Of the 31 studies reviewed eight found no statistical association between lower limb asymmetry and injury risk, 10 studies provided partial statistically significant evidence and a further 10 provided statistically significant statistical links. Conclusion Overall moderate to lower quality evidence for functional asymmetry as a risk factor for injury in sport was observed. While the possibility of a relationship between lower limb functional asymmetry and injury risk cannot be ruled out, further higher quality investigations, adopting standardised methodologies, is required.

Leg strength and multidirectional speed qualities have repeatedly been linked with increased performance during Rugby League (RL) match play and associated with career attainment. However, very little of this evidence for strength has been gained through unliteral measurements with no study available that has examined the impact of strength asymmetry, in this population, on speed qualities in RL players. Therefore, this study examined the association between unilateral strength and as a novel development the subject with the most extreme asymmetry was identified for further analysis. 50 RL players undertook the rear foot elevated split squat five repetition maximum, 20 m linear sprint and modified 505 change of direction test. The mean leg strength for the group was 88.92 ±12.59 kg, when divided by body weight the mean relative strength (REL) was 1.03 ±0.17 kg/kg and the mean asymmetry was 3.21 ±5.70 %. The participant with the greatest asymmetry (subject A) had an imbalance of 33% and a mean leg strength of 75 kg (REL = 0.78 kg/kg) and a body mass one standard deviation above the group mean. Analysis of the group’s data and that of subject A did not indicate that leg strength asymmetry was either frequent or harmful, with respect to speed performance. However, relative leg strength was associated with both improved linear and multidirectional speed. Practitioners are recommended to prioritise the development of relative leg strength and disregard the aspiration for between leg performance symmetry.