postactivation

Postactivation is a term used in physiology and sports science to describe a short-term enhancement of muscle performance following a conditioning activity. It is most commonly discussed as post-activation potentiation (PAP), a transient increase in force, velocity, or power after a prior high-intensity contraction. The term post-activation performance enhancement (PAPE) is also used to emphasize observable performance gains rather than underlying mechanisms.

The leading mechanism for PAP is phosphorylation of myosin regulatory light chains, which increases the sensitivity of the cross-bridges to calcium and can boost force production. Additional contributors include increased neural drive and motor-unit recruitment, as well as elevated muscle temperature and tissue elasticity. Fatigue from the conditioning activity can counteract or negate the benefits, making the net effect highly task- and individual-dependent.

Timing and protocols vary. The magnitude and duration of the benefit depend on factors such as muscle fiber composition, training status, movement type, and the conditioning stimulus. Benefits are typically observed within minutes after activation and may last only a short window, while excessive or poorly chosen stimuli can induce fatigue that reduces performance. Common approaches use heavy resistance or explosive movements, often with a small number of reps, followed by a rest interval before the target task.

Practical application requires individual testing to identify the optimal activation load and timing for a given movement. PAP tends to be more reliable in trained individuals and for tasks resembling the conditioning exercise. Results in the literature are mixed, and environmental factors and measurement methods can influence observed effects.