Effects of warm-up before eccentric exercise on indirect markers of muscle damage

Purpose: To test whether active and passive warm-up conducted before eccentric exercise attenuates clinical markers of muscle damage. Methods: Untrained subjects were exposed to one of five conditions: low-heat passive warm-up (N = 10), high-heat passive warm-up (N = 4), or active warm-up (N = 9), preceding eccentric exercise; eccentric exercise without warm-up (N = 10); or high-heat passive warm-up without eccentric exercise (N = 10). Passive warm-up of the elbow flexors was achieved using pulsed short-wave diathermy, and active warm-up was achieved by concentric contraction. Creatine kinase (CK) activity, strength, range of motion, swelling, and muscle soreness were observed before treatment (baseline) and 24, 48, 72, and 168 h after treatment. Results: High-heat passive warm-up without eccentric exercise did not affect any marker of muscle damage and was used as our control group. Markers of muscle damage were not different between groups that did or did not conduct warm-up before eccentric exercise. The active warm-up and eccentric groups exhibited a greater circumferential increase than controls (P < 0.0002), however, that was not observed after passive warm-up. Additionally, the active warm-up group exhibited a greater CK response than controls at 72 h (P < 0.05). The high-heat passive warm-up before eccentric exercise group exhibited significant change from controls at the least number of time points, but due to a small sample size (N = 4), these data should be viewed as preliminary. Conclusion: Our observations suggest that passive warm-up performed before eccentric exercise may be more beneficial than active warm-up or no warm-up in attenuating swelling but does not prevent, attenuate, or resolve more quickly the other clinical symptoms of eccentric muscle damage as produced in this study.