The effects of soccer specific exercise on countermovement jump performance in elite youth soccer players

Abstract

Purpose. The use of the countermovement jump (CMJ) is common practice in professional soccer (Robineau et al, 2012); however, there is a lack of research regarding the reliability of CMJ performance among youth athletes and changes in performance as a result of exercise-induced fatigue. As such, the aims of the study were twofold: 1) to examine the test-retest reliability of force-time (F-T) characteristics and F-T curve waveform of bilateral and unilateral countermovement jumps (CMJ) in elite youth soccer players; 2)to evaluate the effects of competitive match play on bilateral and unilateral CMJ performance. Methods. 16 male youth soccer players (age: 15.2 ± 2.4 years,) completed three CMJBI (Bilateral), CMJDOM(Dominant) and CMJND(Non-Dominant) at two separate sessions separated by five days to determine repeatability. Participants also completed three CMJBI, CMJDOM and CMJND immediately pre and post and 48 hours following a competitive match to assess exercise-induced neuromuscular fatigue. All data were collected using portable force plates sampling at 1000Hz. Coefficient of variation (CV%), Intra-class correlation coefficient (ICC) and Bland-Altman limits of agreement were used to assess reliability of discrete variables. The reliability of force-time curve waveform was analysed by Statistical Parametric Mapping (SPM), using paired t-tests and individual ICCs. Repeated-measure one way ANOVAs were used to evaluate the effects of soccer match play on discrete force-time variables and SPM was used to evaluate the effects of match play on force-time curve shape .Results. Statistical analysis identified that jump height had limited repeatability in all three jumps and that select jump specific F-T variables were found to be reliable (CV<10%, ICC>0.5). Select variables were reduced immediately post game but recover at 48 hours post game, following exercise-induced fatigue in CMJBI and CMJDOMseparately. F-T curve waveform was found to be repeatable (P>0.05; ICCs>0.5) but not sensitive to change following exercise-induced fatigue. Conclusion. Bilateral and unilateral jump height reliability was poor, and these findings provide important insight in specific F-T characteristics which should be considered for performance monitoring. Jump specific F-T outcome variables changed following exercise-induced fatigue and may allow practitioners to detect decrements in performance among their athletes, which will allow them to evaluate neuromuscular status. Exercise-induced fatigue does not appear to manifest in changes to F-T curve waveform and so SPM does not appear to offer further insight in to changes in CMJ strategy

Date of Award	Mar 2023
Original language	English
Awarding Institution	Coventry University
Supervisor	Jason Tallis (Supervisor), Rhys Morris (Supervisor) & Steven Eustace (Supervisor)