ECCENTRIC STRENGTH-TRAINING MUSCLE DAMAGE LASTS FOR 48 HOURS

Dolezal, B A., Potteiger, J. A., Jacobsen, D. J., & Benedict, S. H. (2000). Muscle damage and resting metabolic rate after acute resistance exercise with an eccentric overload. Medicine and Science in Sports and Exercise, 32, 1202-1207.

This study investigated whether muscle damage, caused by acute resistance exercise with an eccentric overload, would influence resting metabolic rate (RMR) during 72 hours post-exercise. Eccentric exercise causes greater muscle damage than concentric exercise. Ss were resistance-trained (N = 9) and untrained (N = 9) college students. RMR, creatine kinase concentration, and ratings of perceived muscle soreness were evaluated on five consecutive mornings. Muscle damage was induced on day 2 by performing 8 sets 6-RM leg presses.

RMR was elevated in both groups for 48 hours. After 24 hours, RMR significantly decreased over the time span within both groups. Untrained Ss recorded significantly higher creatine kinase and RMR's at 24 and 48 hours than trained Ss. Both creatine kinase and ratings of perceived muscle soreness displayed a similar time course to RMR.

Implication. Eccentrically induced muscle damage causes RMR changes for up to 48 hours after severe resistance exercise. Effects are greater for untrained than trained Ss.

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