Acute effects of an individually timed lower-limb post-activation performance enhancement protocol on 50 m front crawl performance and race kinematics in national-level swimmers.

Post-activation performance enhancement (PAPE) has been proposed as an acute strategy to improve explosive performance, yet its effects on sprint-swimming performance remain unclear, particularly when individualized recovery timing is considered. This study examined the acute effects of a lower-limb PAPE protocol, applied using an individually determined recovery time (IRT), on 50 m front crawl performance and selected start-, race-, and turn-related kinematic variables in national-level male swimmers. Fourteen male national-level swimmers completed a randomized repeated-measures cross-over design comprising control (CON) and PAPE conditions. In the PAPE condition, swimmers performed a lower-limb conditioning protocol consisting of loaded lunge-position squats on a Keiser Squat machine, followed by a maximal 50 m front crawl trial at the end of the IRT. In the CON condition, swimmers completed the same swimming trial without the conditioning stimulus. Lower-limb power output increased significantly after the conditioning activity and reached its highest mean value at 6 min post-exercise (F