Effects of intrasession rest interval on strength recovery and reliability during high intensity exercise

This study examined the effects of intrasession rest interval on reliability and recovery of isokinetic quadriceps and hamstring strength. Subjects were 15 healthy, college age volunteers with no recent weight training experience and no previous history of injury to the lower extremity. Each subject performed 4 sets of 10 reciprocal, concentric, maximal repetitions on the Biodex System II isokinetic dynamometer at a preset angular velocity of 90°/sec. They were randomly assigned to either a short (40 sec) or a long (160 sec) rest interval group. Isokinetic values were obtained for peak torque, total work, and average power. Group 1 had a statistically significant (p < 0.05) reduction in quadriceps and hamstring peak torque, total work, and average power. Group 2 had no significant changes in any dependent measure across the 4 sets of exercise. ICC coefficients and SEMs for quadriceps and hamstring peak torque, total work, and average power ranged from 0.98-0.99 (SEM 2.2-4.7%) for Group 2, and 0.78-0.92 (SEM 5.1-7.7%) for Group 1. The findings indicate that a rest : exercise ratio of 2:1 may not be long enough to allow full recovery of isokinetic force capacity between exercise bouts.