INCREASED POPULARITY IN THE UTILIZATION OF FORCE PLATES TO MEASURE COUNTERMOVEMENT JUMPS (CMJS) FOR PERFORMANCE MONITORING WARRANTS THE NEED FOR STRENGTH AND CONDITIONING COACHES AND SPORT SCIENTISTS TO BETTER UNDERSTAND ITS FORCE-TIME CHARACTERISTICS AND THE CALCULATION OF ITS ASSOCIATED VARIABLES. THIS ARTICLE AIMS TO PROVIDE INFORMATION ON HOW TO UNDERSTAND AND ANALYZE THE FORCE-TIME CURVE OF CMJS IN MICROSOFT EXCEL, THUS PROVIDING PRACTITIONERS AN INEXPENSIVE AND ACCESSIBLE ALTERNATIVE TO READILY AVAILABLE SOFTWARE ON THE MARKET.

The aims of the present study were to determine test-retest reliability for unilateral strength and power tests used to quantify asymmetry and determine the consistency of both the magnitude and direction of asymmetry between test sessions. Twenty-eight recreational trained sport athletes performed unilateral isometric squat, countermovement jump (CMJ) and drop jump (DJ) tests over two test sessions. Inter-limb asymmetry was calculated from both the best trial and as an average of three trials for each test. Test reliability was computed using the intraclass correlation coefficient (ICC), coefficient of variation (CV) and standard error of measurement (SEM). In addition, paired samples t-tests were used to determine systematic bias between test sessions and Kappa coefficients to report how consistently asymmetry favoured the same side. Within and between-session reliability ranged from moderate to excellent (ICC range = 0.70–0.96) and CV values ranged from 3.7–13.7% across tests. Significant differences in asymmetry between test sessions were seen for impulse during the isometric squat (p = 0.04; effect size = –0.60) but only when calculating from the best trial. When computing the direction of asymmetry across test sessions, levels of agreement were fair to substantial for the isometric squat (Kappa = 0.29–0.64), substantial for the CMJ (Kappa = 0.64–0.66) and fair to moderate for the DJ (Kappa = 0.36–0.56). These results show that when asymmetry is computed between test sessions, the group mean is generally devoid of systematic bias; however, the direction of asymmetry shows greater variability and is often inter-changeable. Thus, practitioners should consider both the direction and magnitude of asymmetry when monitoring inter-limb differences in healthy athlete populations.

Weightlifting is a highly technical sport that is governed by interactions of phases to optimize the load lifted. Given the technicality of the snatch and the clean and jerk, understanding key stable components to identify errors and better prescribe relevant exercises are warranted. The aim of this article is to present an applied method of analysis for coaches that considers the biomechanical underpinnings of optimal technique through stable interactions of the kinetics and kinematics of the lifter and barbell at key phases of the lift. This article will also look to discuss variable components that may differentiate between athletes and therefore provide a foundation in what to identify when coaching weightlifting to optimize load lifted while allowing for individual variances.

Understanding force generating capabilities of athletes is an important facet of strength diagnostics. The use of isometric tasks such as the isometric squat and isometric midthigh pull are therefore popular methods used to gain a deeper understanding as to what strength characteristics have changed over a given period. This article aims to provide information on how to understand and analyse the force-time curve of isometric tasks in microsoft excel, thus providing practitioners an inexpensive and accessible alternative to readily available software on the market.

The kinetic analysis of joint work and joint contribution provides practitioners with information regarding movement characteristics and strategies of any jump test that is undertaken. This study aimed to compare joint works and contributions, and performance metrics in the countermovement jump (CMJ), drop jump (DJ), and countermovement rebound jump CMRJ. Thirty-three participants completed 18 jumps across two testing sessions. Jump height and strategy-based metrics (time to take-off [TTTO], countermovement depth [CM depth], and ground contact time [GCT]) were measured. Two-way analysis of variance assessed systematic bias between jump types and test sessions (α = 0.05). Reliability was evaluated via intraclass correlation coefficient [ICC] and coefficient of variation [CV]. Jump height and strategy-based metrics demonstrated good to excellent reliability (ICC = 0.82–0.98) with moderate CV (≤8.64%). Kinetic variables exhibited moderate to excellent reliability (ICC = 0.64–0.93) with poor to moderate CV (≤25.04%). Moreover, apart from TTTO (p ≤ 0.027, effect size [ES] = 0.49–0.62) that revealed significant differences between jump types, CM depth (p ≤ 0.304, ES = 0.27–0.32) and GCT (p ≤ 0.324, ES = 0.24) revealed nonsignificant trivial to small differences between three jumps in both sessions. Finally, the negative and positive hip and knee works, and positive ankle contribution measured in the CMRJ showed significant differences from the CMJ and DJ (p ≤ 0.048, g ≤ 0.71), with no significant difference observed in other kinetic variables between the three jump actions (p ≥ 0.086). Given the consistent joint works and joint contributions between jump types, the findings suggest that practitioners can utilize the CMRJ as a viable alternative to CMJ and DJ tests, and the CMRJ test offers valuable insights into movement characteristics and training suggestions.

Rugby union (RU) is a field-based team sport with a large number of high-intensity actions such as sprinting, change of direction, tackling, scrummaging, rucking, and mauling. Competitive success in female RU has previously been related to anthropometric and physical characteristics, and with the recent introduction of professionalism in female rugby, characterizing such physical attributes may provide insight into selection and training processes. Purpose: To identify anthropometric and physical characteristics of competitive female RU players and differences between playing positions. Methods: Twenty-two players were recruited from the top tier of female RU in the United Kingdom during the 2018–2019 Premiership season. Players were split into forwards and backs and underwent body composition testing via dual-X-ray absorptiometry and physical characteristic tests (10- and 20-m speed, 1-repetition-maximum bench press and squat, countermovement jump, drop jump, isometric midthigh pull, and 1200-m shuttle). Results: Moderate to large significant differences between playing positions in both anthropometric and physical characteristics were found (P < .01). Forwards displayed greater body mass (P = .03), fat mass (P = .01), and absolute upper-body strength (P = .03), whereas backs demonstrated superior countermovement jump height (P = .01), drop jump height (P = .01), greater reactive strength (P = .03), and speed (P = .03). Conclusion: These findings provide practitioners with a greater understanding of anthropometric and physical characteristics of professional female RU players.