A Mechanistic Perspective on Post-Activation Performance Enhancement Responsiveness: A Randomized Controlled Study of Acute Changes in Muscle Architecture, Contractile Property Kinetics, and Muscle Excitability

Participants in the conditioning arm perform a single set of two to three half-squats with a free-weight barbell set at 90% of their one-rep max (1RM). Each squat is taken down until the thigh is parallel to the floor (knee at \~90°) and then driven upward as explosively as possible.

Participants engaged in a standardized 5-minute treadmill warm-up. Participants were instructed to walk at a moderate, self-selected pace of approximately 7-9 km/h, maintaining an incline of 0%. Heart rate and perceived exertion were monitored to ensure that the activity remained within a light-intensity range (Borg scale: 6-11).