Cocoa flavanol effects on markers of oxidative stress and recovery after muscle damage protocol in elite rugby players.

Abstract

Strenuous exercise can impair athletic performance due to muscular inflammation and oxidative stress. Antioxidants such as cocoa flavanols have been used as a supplement to prevent oxidative stress; however, the benefits of dietary antioxidants for athletic performance after muscle soreness (MS) is unclear. The purpose of this study was to examine the effects of cocoa flavanols after a MS inducing protocol. In a randomized, double-blinded design, 13 male collegiate rugby players consumed either chocolate milk (CHOC) or chocolate milk with additional cocoa flavanols (CocoaCHOC) during a 7-d loading phase. MS was induced by a drop jump protocol on day 5 of the intervention. Athlete performance was assessed with vertical-jump and yo-yo tests and subjective measures of soreness 5 d before and 2 d post-MS protocol. Urinary markers of oxidative stress (isoprostanes) were assessed before and 48 h post-MS. No changes were observed between the groups over time for isometric torque (P = .63), vertical jump performance (P = .39), and yo-yo testing (P = .57) between the trials. No interaction was found in isoprostanes levels between the trials (CocoaCHOC baseline: 88 ± 0.38 pg/mL and 48 h post-MS: 81 ± 0.53 pg/mL; P = .82; and CHOC baseline: 98 ± 0.96 pg/mL and 48 h post-MS: 96 ± 0.38 pg/mL; P = .59). No main effect (treatment × time; P = .58) was observed for isoprostanes. Although not significant, the CocoaCHOC group ran 97 meters further than the CHOC group in the yo-yo test. Cocoa flavanols added to a post-exercise recovery beverage for 7 d has no oxidative stress or athletic performance benefits.