Changes in the force development characteristics of muscle following repeated maximum force and power exercise.

There is some evidence to suggest that ability to develop force in skeletal muscle can be improved for a short period following repeated maximal strength exercise. Some studies have suggested the phenomenon known as post-activation potentiation (PAP) to explain this immediate response to such exercise. However, little is known about the physical and temporal characteristics of the changes in muscle function due to PAP when induced using whole-body maximal strength exercise. The purpose of this study was to establish the physical and temporal characteristics of PAP of muscle function in elite male athletes following maximum strength and power exercise. Fifteen participants performed one of repeated maximal strength exercise or maximal power exercise or a control protocol on separate occasions. Changes in maximum isometric voluntary force (iMF), maximum isometric rate of force development (iRFD) and maximum vertical counter-movement jump (CMJ) were assessed. Results suggest that post-activation potentiation of iRFD occurs but is preceded by an initial suppression of force development capability following repeated maximal strength exercise. Following repeated maximal power exercise, however, post-activation potentiation of iRFD occurs immediately but is not seen over as long a period as that observed following maximal strength exercise. These results suggest that post-activation potentiation does bring about increased force development capability following intense exercise and that the temporal profile of the post-activation potentiation changes with intensity of the exercise used to induce it.