The Effects of Rest Interval on Peak Torque in Females During Isokinetic Knee Extension

Abstract

This study evaluated the effect of rest period on peak torque production during knee extension at five different velocities. PURPOSE: The purpose was to investigate the optimal rest period for females during isokinetic testing in attempts to standardize these values for future testing or rehabilitation protocols. Secondly, the difference in peak torque between female athletes and non-athletes was investigated. METHOD: Female athlete (N=12) and non-athlete (N=11) subjects with no history of knee injury were recruited from the University of Puget Sound to attend three familiarization and four test sessions to perform four maximal knee extensions at 60, 120, 180, 240, and 300°·sec−1. Rest periods were randomly assigned between velocity sets at 15, 60, 180, or 300 seconds. Peak torque was recorded for each trial. Data were analyzed by using a 2 x 4 x 5 design with group, rest, and velocity as the independent variables, and peak torque as the dependent variable. RESULTS: Familiarization sessions one and two yielded a correlation coefficient of =.881, while familiarization sessions two to three yielded a correlation of r =.955, indicating that subjects became more acclimated to the isokinetic testing device as they performed more trials. A repeated measures ANOVA was used to analyze the data with a level of significance of p < 0.05. There were no significant differences between the rest periods for either group. There was an interaction between athletes and velocity, meaning that athletes had a higher mean peak torque at all velocities than non-athletes. A significant difference was found between the velocities regardless of rest period F=720.035, p<.05) and coincided with the results of Parcell et al (2002). Additionally, there was a significant difference between peak torque production athletes and nonathletes (F=15.585, p<.05), which suggests that athletes understand maximal effort more readily than non-athletes. CONCLUSION: Recovery time in females seems adequate at any of the four tested rest periods. However, it seems reasonable that with only four repetitions a 60 second rest would ensure proper recovery. Supported by research grant from the University of Puget Sound.