Post-activation Potentiation Versus Post-activation Performance Enhancement in Humans: Historical Perspective, Underlying Mechanisms, and Current Issues

Post-activation potentiation (PAP) is a well-described phenomenon with a short half-life (~30 s) that enhances muscle force production at submaximal levels of calcium saturation (i.e. submaximal levels of muscle activation). It has been largely explained by increased myosin light chain phosphorylation occurring predominately in type II muscle fibers, and can be tested in humans by measuring muscle twitch force responses to a bout of muscular activity. However, enhancements in (sometimes maximal) voluntary force production detected several minutes after high-intensity muscle contractions have also been observed, and which are also most prominent in muscles with a high proportion of type II fibers. This has…