Purpose: Fourteen male cyclists were studied to compare the effect of carbohydrate-protein-antioxidant beverage (CHOPA) to an isocaloric carbohydrate-only (CHO) beverage on time to fatigue and muscle damage. Methods: Subjects performed two sets of rides to exhaustion on a cycle ergometer. In each set, the first ride was performed at 70% V[spacing dot above]O2peak, and the second was performed 24 h later at 80%. CHO or CHOPA was consumed every 15 min during exercise and immediately afterward. Plasma CK and LDH and muscle soreness were measured pre- and postexercise. Results: Time to fatigue was not different between CHO and CHOPA at 70% V[spacing dot above]O2peak (95.8 +/- 29.7 vs 98.1 +/- 28.7 min), 80% V[spacing dot above]O2peak (42.3 +/- 18.6 vs 42.9 +/- 21.8 min), or total performance time (138.1 +/- 39.3 vs 140.9 +/- 43.7 min). Postexercise CK was increased (P < 0.05) from baseline in CHO (203 +/- 120 vs 582 +/- 475 U[middle dot]L-1) but not with CHOPA (188 +/- 119 vs 273 +/- 169 U[middle dot]L-1). Similarly, LDH values increased over baseline in CHO (437 +/- 46 vs 495 +/- 64 U[middle dot]L-1) but not with CHOPA (432 +/- 40 vs 451 +/- 43 U[middle dot]L-1). Postexercise CPK and LDH were higher after the CHO trial than after the CHOPA trial. Median postexercise muscle soreness was higher in CHO (3.0 +/- 5.0) than with CHOPA (1.0 +/- 3.0). Conclusion: No differences in time to fatigue were observed between the beverages, despite lower total carbohydrate content in the CHOPA beverage. The CHOPA beverage attenuated postexercise muscle damage, as evidenced by CK and LDH values, compared with an isocaloric CHO beverage.
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