An age-related decrease in muscular strength may have a detrimental effect on muscle fatigue and recovery. To date, only one study has determined the effect of varied rest intervals (RI) between exercise sets in active younger and older women. They reported that active younger and older women require similar RI between sets to recovery full isokinetic knee extension peak torque (PT). However, we are unaware of any published studies comparing RI PT recovery between younger and older men. Thus, the purpose of this study was to compare the effect of two different RI's between sets of isokinetic knee extension exercise on PT, and Total Work (TW) between untrained younger and older men.