The effects of a competitive soccer match on jump performance and inter-limb asymmetries in elite academy soccer players

The purpose of the present study was to investigate the effects of a competitive soccer match on jump performance and inter-limb asymmetries over incremental time points during a 72-hour (h) period. Fourteen elite adolescent players from a professional English category three academy performed single leg countermovement jumps (SLCMJ) pre, post, 24, 48, and 72-h post-match on a single force platform. Eccentric impulse, concentric impulse, peak propulsive force, jump height, peak landing force, and landing impulse were monitored throughout. Inter-limb asymmetries were also calculated for each metric as the percentage difference between limbs. Significant negative changes (p < 0.05) in jump performance were noted for all metrics at all time points, with the exception of jump height. Inter-limb asymmetries were metric-dependent and showed very large increases, specifically post-match, with a trend to reduce back towards baseline values at the 48-h time point for propulsive-based metrics. Asymmetries for landing metrics did not peak until the 24-h time point and again reduced towards 16 baseline at 48-h. The present study highlights the importance of monitoring distinct jump metrics, as jump height alone was not sensitive enough to show significant changes in jump performance. However, inter-limb asymmetries were sensitive to fatigue with very large increases post-match. More frequent monitoring of asymmetries could enable practitioners to determine whether existing imbalances are also 20 associated with reductions in physical performance or increased injury risk