The purpose of this study was to investigate the effects of resting periods between exercise sets during isokinetic contraction on recovery from muscle fatigue, strength, heart rate, blood pressure, and lactate level. Sixteen women performed 10 repetitions of isokinetic exercise for three sets in three different conditions. During the sets, they rested 50, 100, and 150 seconds in each condition. And the results were: 1) In this population, the peak torque of extensor during the isokinetic exercise in 100 second resting condition was significantly higher than that in 50 and 150 second resting conditions (p<.01). The total work of extensor was significant in the second and third sets in 50 and 100 second resting conditions (p<.01). 2) During the isokinetic exercise, the heart rate was progressively increased as the sets were advanced in all resting conditions (p<.01). And the increase was significant during the second and third sets than the first in 50 second resting condition (p<.01), while it was significantly greater after the third set than the first in 100 and 150 second resting conditions (p<.01). 4) No difference was found between the resting periods in blood lactate level and blood pressure during the isokinetic exercise. However, differences were found between the sets in these variables (p<.01).