| This goal of this study was to test the influence of active and passive warm-up, conducted prior to eccentric exercise, on indirect markers of muscle damage. A 5 x 5 factorial with repeated measures on one factor guided this study. Untrained subjects (N = 43) were treated with one of five treatment groups: low heat passive warm-up, high heat passive warm-up, or active warm-up preceding eccentric exercise, eccentric exercise without warm-up, or high heat passive warm-up without exercise. Passive warm-up was achieved by applying pulsed short-wave diathermy to the elbow flexors, and active warm-up was achieved by concentrically contracting the elbow flexors. Pilot work demonstrated that the low and high passive warm-up treatments using pulsed short-wave diathermy resulted in an approximate 1°C and 3.5°C rise in muscle temperature of the biceps brachii, respectively, taken at a depth of two cm. The active warm-up treatment resulted in approximately a 1°C temperature rise. The effects of treatments were noted on creatine kinase activity, strength, range of motion, swelling, and muscle soreness at five times: prior to treatment (baseline) and at 24, 48, 72, and 168 hours following treatment. The data were analyzed with an overall MANOVA using NCSS 2000 software, followed by multiple ANOVA's and Tukey-Kramer post-hoc tests if significant main effects or interactions were found. Statistical significance was set at P < 0.05. Heat alone did not affect any marker of muscle damage, and was excluded from further analysis. There were no differences between the remaining groups for any dependent variable at any time. As observed in numerous similar studies, significant changes across time followed eccentric exercise: (1) creatine kinase activity was elevated from baseline at 72h (P = 0.004); (2) strength declined by 34--40% at 24h (P < 0.05), and recovered in a similar fashion for all groups; (3) range of motion decreased from baseline at 24h, 48h and 72h (P < 0.05); and (4) soreness increased at 24h, 48h and 72h (P < 0.05). We conclude that warm-up does not appear to prevent, attenuate, or resolve more quickly, the clinical symptoms of eccentric muscle damage as produced in this study. |
