Pre-Activity Maximal Isometric Contraction Improves Jump Height and Power Output

Postactivation potentiation (PAP) is a term that has received considerable attention by the strength and conditioning community within recent years. PAP refers to enhanced contractile capabilities brought about by some type of exercises prior to performance and may be influenced by a number of factors.

This study examined the influence of type of muscle contraction (isometric vs. dynamic), gender, and previous weightlifting experience on PAP as demonstrated by changes in jump height and power output. Thirty young men and women, classified as either having previous weightlifting experience or not, performed 3 different sets of countermovement jumps, with the first set used to determine baseline measures of jump height and power. The second set was performed after a maximal isometric squat protocol (maximal voluntary contraction [MVC]-PAP) to induce PAP, and the third set of jumps was performed after a maximal dynamic squat (DS) protocol (DS-PAP). Jump height after the MVC-PAP protocol was significantly higher than both the pretest and DS-PAP values; men performed significantly better than women; and experienced lifters responded more favorably than the inexperienced lifters. Jump power was also significantly greater for the MVC-PAP condition compared with the other 2 conditions, and DS-PAP power also improved when compared with the pretest values, with men performing significantly better than women. All results remained consistent after accounting for height and weight differences (body mass index) between the groups.

In conclusion, the isometric condition (MVC-PAP) evoked a greater muscle postactivation potentiation than the dynamic condition (DS-PAP), and postactivation was enhanced by previous weightlifting experience. The practical manipulation of MVC by pushing, squatting, or both against fixed objects, such as walls and low ceilings, could be a very simple and cost-effective way to arouse a state of PAP before sports performance that requires high force and power outputs.

Rixon P, Lamont H, Bemben M. (2007). Influence of type of muscle contraction, gender, and lifting experience on postactivation potentiation performance. Journal of Strength and Conditioning Research, 21(2): 500-505.