Do Older Men Require Different Rest-Intervals Between Sets Than Younger Men During Isokinetic Muscle Contractions?

Abstract

An age-related decrease in muscular strength may have a detrimental effect on muscle fatigue and recovery. Todate, 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. PURPOSE: 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. METHODS: 18 young men (24.22 ± 2.58 yrs) and 20 older men (66.85 ± 4.02 yrs) performed 3 sets of 10 unilateral isokinetic knee extension repetitions at 60°/s. The rest intervals between sets were 1 and 2 minutes and were counterbalanced across 2 testing days, separated by a minimum of 48 hours. The work-to-rest ratio was 1:3 and 1:6. All subjects were not involved in exercise programs that included resistance exercises within the last 6 months. Statistical evaluation of the data was performed using a 2 × 2 × 3 mixed factor repeated measures ANOVA [age (younger and older) x rest interval (1 and 2 min) × set (1st, 2nd, and 3rd)]. Statistical significance was set at p < 0.05 for all comparisons. RESULTS: The results were as follows:CONCLUSION: Non-resistance trained young men may require longer RI′s to recover full PT and TW when compared to older men. These results suggest that younger men exhibit the capacity to produce greater muscular force, and as a consequence may develop a higher level of fatigue than older men. Also, it appears that older men require longer RI between the second and the third sets.