Rest Interval Effects On Prolonged Epoc

Abstract

Resistance exercise programs utilizing limited rest intervals have become increasingly popular, but their effects relative to traditional training routines is unproven. Following exercise of sufficient intensity, increases in resting metabolic rate (RMR) have been observed for up to 72 hours post exercise. While an initial investigation resulted in no significant differences in energy expenditure during the short phase of recovery between resistance exercise bouts performed using vastly different rest intervals its effects on the prolonged phase of recovery are unknown. PURPOSE: To elucidate the effects of rest interval on prolonged energy expenditure secondary to resistance exercise. METHODS: 12 recreationally trained females twice had their RMR assessed on four consecutive days. The two four-day measurements were separated by one month and sequences were set using a crossover design. On the second day of each trial period participants performed a circuit type full body free weight lifting exercise routine with either short (15 seconds) or long rest intervals (150 seconds). The work performed was of equal volume and intensity, and each repetition was paced using a metronome. RESULTS: With respect to RMR there were no significant time or treatment effects (p = 0.98 and p = 0.35 respectively), though there was an interaction effect between time and treatment (p < 0.01). On the second day following exercise (39 hours post) the low rest treatment resulted in an average RMR of 1331±165.25 kcal versus 1235.67±115.59 kcal observed in the high rest treatment (p < 0.05). CONCLUSION: Resistance exercise performed using lower rest intervals appears to result in greater rates of energy expenditure during the prolonged phase of recovery. While the mechanisms underlying this phenomenon are not entirely understood, muscle soreness ratings suggest a link to muscle damage is a strong possibility.