Purpose: To investigate the post-activation potentiation (PAP) effects of different eccentricoverload (EOL) exercise volumes on countermovement jump (CMJ) and standing long jump (LJ) performance. 89 Methods: Thirteen male university soccer players participated in a cross over design study following a familiarization period. Control (no PAP) CMJ and LJ performances were recorded, and three experimental protocols were performed in a randomized order: 1, 2 or 3 sets of 6 repetitions of flywheel EOL half-squats (inertia=0.029 kg·m2). Performance of CMJ and LJ were measured at 3 and 6 min following all experimental conditions. The time course and magnitude of the PAP were compared between conditions. Results: Meaningful positive PAP effects were reported for CMJ after 2 (Bayes factor [BF10]=3.15, moderate) and 3 (BF10=3.25, moderate) sets but not 1 set (BF10=2.10, anecdotal). Meaningful positive PAP effects were reported for LJ after 2 (BF10=3.05, moderate) and 3 (BF10=3.44, moderate) sets but not 1 set (BF10=0.53, anecdotal). Two and three set protocols resulted in meaningful positive PAP effects on both CMJ and LJ after 6 but not 3 min. Conclusion: This study reported beneficial effects of multiple-set eccentric overload exercise over a single set. A minimum of two sets of flywheel EOL half-squats are required to induce PAP effects on CMJ and LJ performance of male university soccer players. Rest intervals of around 6 min (greater than 3 min) are required to maximize the PAP effects via multiple sets of EOL exercise. However, further research is needed to clarify the optimal EOL protocol configurations for PAP response.