POST-ACTIVATION POTENTIATION AND VERTICAL JUMP PERFORMANCE

Abstract

PURPOSE: A technique used to enhance acute performance that involves a short, high intensity stimulus followed by a dynamic or isometric movement is referred to as post-activation potentiation (PAP). The acute performances increases have been attributed to both physiological and neurological factors. To date, research on this technique has not investigated the muscular activity during a dynamic vertical jump test of the upper leg muscles. The purpose of this study was to determine how using the PAP technique effects the direct force output of different types of vertical jumps as well as measuring differences with rate of force development curves from baseline outputs.

METHODS: Three male college-aged subjects underwent two days of testing. On the first session, subjects performed one maximum leg extension on the Cybex machine at speeds of 30,60,90,120,180 d/s. Force output and muscular activity of two quadriceps and two hamstring muscles were measured. On the second session, subjects performed a three-second maximum voluntary contraction of the leg extension exercise. Following a rest period of either 30 seconds or 5 minutes, subjects performed a countermovement or squat jump. Force output from the force platform was measured along with muscular activity of the same muscles as day one. The order at which subjects performed leg extensions at different speeds on day one and the rest intervals and type of jump performed on day two were all randomized.

ANALYSIS: The resting interval between the maximum voluntary contractions and the speeds of leg extension were independent variables. The force output and muscular activity were the dependent variables. Repeated measures ANOVA tests were used to examine the effects of PAP on vertical jumping.

RESULTS: With each jump type and rest interval, the force development was divided into four parts for each of the four muscle groups. There were significant differences (p<0.05) found between the quarters of movement in the following muscles and jumps: Vastus Lateralis - squat jump control. Vastus Medialis – squat jump control, squat jump 30s. Biceps femoris – squat jump 30s. Semitendinosus – squat jump 30s, squat jump 5 minutes. There were no significant (p>0.05) differences found in force output following both jump types and both resting intervals. However, the total force output from the countermovement jump increased by 7.9% after resting 30 seconds and by 12.9% after resting for 5 minutes following PAP.