RESUMO
PURPOSE: This study was conducted to determine if 6 wk of supplementation with vitamins E and C could alleviate exercise-induced muscle damage. We studied 22 runners during a 50-km ultramarathon. METHODS: Subjects were randomly assigned to one of two groups: (a) placebos (PL) or (b) antioxidants (AO) (1000 mg vitamin C and 300 mg RRR-alpha-tocopheryl acetate). Blood samples were obtained before supplementation (baseline), 24 h pre-, 12 h pre-, and 1 h prerace; midrace, postrace, 2 h postrace, and for 6 d postrace. Plasma alpha-tocopherol (alpha-TOH), ascorbic acid (AA), and muscle damage markers (creatine kinase (CK) and lactate dehydrogenase (LDH)), as well as maximal voluntary contraction (MVC) of the hamstring and quadriceps were assessed. RESULTS: With supplementation, plasma alpha-TOH and AA increased in the AO but not the PL group. LDH and CK increased in response to the race; LDH peaked at postrace and CK reached maximal values 2 h and 1 d postrace; neither was affected by treatment. Adjusting for between-subject differences in baseline CK values revealed that men had higher levels of CK than did women throughout the study. Correcting CK values for lean body mass (kg) eliminated sex differences, but not changes over time. CK was significantly correlated (R = 0.52, P < 0.0001) with C-reactive protein, an acute phase response marker. MVC decreased 14-26% in all groups in response to the run. Eccentric hamstring (EH) torque and concentric quadriceps (CQ) power exhibited the largest deficits, 26 and 24%, respectively, with no effect of treatment. CQ recovered at a faster rate in women than in men. CONCLUSION: Antioxidants appeared to have no effect on exercise-induced increases in muscle damage or recovery, but important sex differences were observed.
