POST EXERCISE METABOLIC RATE FOLLOWING DOWNHILL RUNNING

Abstract

An acute eccentric exercise bout produces muscle damage and delayed onset muscle soreness (DOMS). Both are attenuated following a subsequent eccentric exercise bout indicating that an adaptation occurs. The degree to which this type of exercise influences recovery energy expenditure is unknown. PURPOSE: We investigated whether excess postexercise oxygen consumption (EPOC) measured for 2h and resting metabolic rate (RMR) measured 24h (day 2) and 48h (day 3) post-exercise would differ following level vs downhill treadmill running. METHODS: Eight untrained male subjects performed three 40min submaximal exercise trials eliciting ∼70% VO2max: a level running trial and two downhill running trials (DH1 and DH2). DH1 was performed 1wk after level, and DH2 2wk after DH1. Testing occurred in the morning following an overnight fast and no strenuous exercise for the previous 36h. Baseline RMR was measured for 30min pre-exercise. DOMS was rated for five lower body sites at 24h and 48h post exercise. Analyses included 1- and 2-way ANOVA and Friedman tests. RESULTS: When compared to baseline, VO2 was significantly elevated at 60 (p < .01) and 90min (p < .03) for DH1 and at 60min (p < .03) for DH2, whereas VO2 was not significantly elevated at any of these time points during the level trial. However, there was no significant difference in the accumulated 2h EPOC among trials (level = 7.04/5.32, DH1 = 8.55í4.12, and DH2 = 8.38í2.89 L). RMR was not significantly different among days or among trials. DH1 produced significantly greater DOMS than level running (p < .01) at all 5 sites. CONCLUSION: It can be concluded that the first bout of downhill running for 40min at a moderately high intensity, which produced a significant amount of DOMS, resulted in a prolonged EPOC (> 90min). However, an elevated metabolic rate was not detected 24 or 48th following exercise when DOMS was evident. In contrast, metabolic rate returned to the resting value within 1h after running on a level grade. The physiological mechanisms involved in producing a prolonged elevation in metabolic rate following downhill running remain to be elucidated.