The effects of resistance band–induced post-activation performance enhancement on Gyaku-Zuki punch kinematics in elite male karate athletes

Post-activation performance enhancement (PAPE) describes a transient improvement in voluntary explosive performance following a conditioning activity. The magnitude and time course of PAPE depend on the characteristics of the conditioning stimulus, the muscles and movement patterns involved, athlete characteristics, and the balance between potentiation-related effects and residual fatigue. Although resistance-band conditioning can provide a movement-specific stimulus, the temporal response of karate-specific striking performance following resisted punching remains unclear. This study investigated the acute effects of a resistance-band conditioning protocol on three-dimensional Gyaku-Zuki punch (GZP) kinematics in elite male Shotokan karate athletes. Fifteen elite male Shotokan karateka (mean age 21.1 ± 3.9 years) participated in a randomized, counterbalanced crossover study. Participants completed standardized experimental sessions, including a baseline assessment and a resistance-band conditioning condition. The conditioning protocol consisted of two sets of five maximal Gyaku-Zuki punches with the elastic band set to an initial resistance of 30 ± 2 N at the standardized starting position, measured using a calibrated digital force gauge (FG-5000 A, Lutron) at the standardized starting position. Because elastic resistance changes with band elongation, 30 ± 2 N represented the standardized initial resistance rather than a constant force throughout the punch. Kinematic variables, including mean punch velocity (MPV), peak punch velocity (PPV), and punch execution time (PET), were recorded using a three-dimensional motion-capture system at 340 Hz. Data were analyzed using repeated-measures analysis of variance with Bonferroni-adjusted post hoc comparisons. Time significantly affected MPV, PPV, PET, and perceived exertion. MPV increased by 14.4% at 8 min ( p = 0.001) and 12.3% at 12 min ( p = 0.002), while PPV decreased at 15 s and increased at 8 min (η² p = 0.642). PET was shorter from 15 s to 12 min, with the largest reduction at 8 min. The omnibus effects were large for all three kinematic outcomes (η² p = 0.642 for PPV, 0.773 for PET, and 0.804 for MPV). A resistance-band conditioning activity was followed by time-dependent changes in GZP kinematics, with the clearest improvements occurring 8–12 min after the conditioning activity. These findings suggest that sport-specific resistance-band conditioning may be a useful component of a pre-performance warm-up in elite male Shotokan karate, while the fixed initial tension and absence of kinetic measurements limit recommendations about loading and impact performance.