Optimization of post-activation potentiation in girls and women.

Abstract

Maximal conditioning contractions (CCs) can lead to the enhancement of evoked-twitch characteristics in human skeletal muscle. This phenomenon is termed post-activation potentiation (PAP). In the knee extensors, PAP is greater in men compared with boys. In adults, the optimal CC duration for PAP is ~ 10s. We examined child-adult differences in PAP among females and aimed to determine the optimal CC duration in girls and women. Eleven girls (9.3 ± 1.4years) and 13 women (23.4 ± 2.7years) participated in this study. Maximal isometric evoked twitches were recorded in the knee extensors before and after 4 maximal CCs of different durations (5, 10, 20, and 30s), in a random order. PAP was calculated as the percent-change in peak torque (Tpeak) and peak rate of torque development (RTDpeak) after each CC. There was a group-by-duration interaction (p < 0.001), reflecting greater Tpeak PAP in women compared with girls following 5 and 10s CCs, and lower RTDpeak PAP in women following the 30s CC. The 5 and 10s CCs lead to the greatest Tpeak and RTDpeak PAP amongst the women while there were no differences between CC durations in girls. After both a 5 and 10s CC, women have greater PAP compared with girls. The optimal CC duration for the knee extensors in women appears to be ~ 5-10s, while CC durations between 5 and 30s do not appear to affect levels of PAP in girls.