The effects of strength, aerobic, and concurrent exercise on skeletal muscle damage in rats.

Introduction: In this study we examined oxidative stress and skeletal muscle damage resulting from acute strength, aerobic, or concurrent exercise in rats.

Methods: The animals were divided into control (C), strength (SE), aerobic (AE), and combined (CE) exercise groups. They were euthanized at 3 different time-points (6, 24, and 48 h) after acute exercise.

Results: SE exercise rats had increased dichlorofluorescein oxidation at 6 h post-exercise and decreased superoxide dismutase activity at all time-points. Glutathione peroxidase activity and sulfhydryl levels were increased in the AE group at 48 h post-exercise. Serum lactate dehydrogenase activity was increased in the SE and CE groups at 24 h and in the AE group at 48 h. Echo intensity was elevated at 24 h for all groups.

Conclusions: Forty-eight hours was sufficient for complete recovery from oxidative stress and muscle damage in the SE and CE groups, but not in the AE group.