Strength-Dependent Differences in the Magnitude and Time Course of Post-Activation Performance Enhancement in High Jump Athletes

<b>Background</b>: A post-activation performance enhancement (PAPE) can acutely improve explosive actions, but its time course may be influenced by individual strength levels. <b>Objectives</b>: The aim of this study was to analyze the performance responses following three PAPE protocols, considering the strength level as a modulating factor in trained high jump athletes. <b>Methods</b>: Twenty-one male high jumpers (Tier 3) were divided into stronger (SG, n = 10) and weaker (WG, n = 11) groups based on the median load (80 kg) lifted at 0.8 m/s in a velocity-based half-squat test. The participants completed three squat-based PAPE protocols (velocity loss thresholds of 5%, 10%, and 15%) in a randomized, double-blind crossover design. Their performance in a 10 m sprint (S10) and a countermovement jump (CMJ) was assessed at baseline and 0, 4, 8, and 12 min post-intervention. <b>Results</b>: No significant three-way interactions were observed for the S10 or CMJ performance (<i>p</i> > 0.05). The absolute CMJ performance was consistently higher in the SG across all the time points (<i>p</i> < 0.001, d = 1.25, large), with significant peak values observed at 4 min post-activation. However, both groups exhibited transient improvements in their S10 and CMJ performance that were statistically significant (<i>p</i> < 0.05) and of a large magnitude (d = 1.93-3.15), observed at 4 and/or 8 min post-activation, which subsequently declined by 12 min. <b>Conclusions</b>: The strength level modulates both the time course and the magnitude of the PAPE. Stronger athletes responded better to both less and more demanding protocols (5% to 15% velocity loss thresholds) with a 4-8 min recovery, whereas weaker athletes benefited mainly from less demanding stimuli (5% velocity loss thresholds), provided that the recovery was sufficient (≈4 min) to allow potentiation to emerge. However, with more demanding protocols (15% velocity loss thresholds), a longer recovery period (≈8 min) appears necessary.