Effects Of Olive Extract Supplementation On Post-exercise Markers Of Muscle Recovery

Abstract

PURPOSE: Olive extract (OE) is derived from the aqueous fraction of olives and is rich in polyphenols, including the potent antioxidant hydroxytyrosol (HT). Previous studies have shown that olive poyphenols can confer antioxidant protection in vivo, as shown by increased plasma total antioxidant capacity and protection against LDL oxidation. Antioxidants may affect muscle recovery following strenuous exercise. The purpose of this study was to determine if OE supplementation influenced plasma creatine kinase (CK), muscle soreness, and muscle function following heavy aerobic exercise. METHODS: 19 male subjects (21.2±2.9 yr, 23.9±1.7 BMI) underwent 3 treatment phases, consisting of 14-day supplementation periods with either 0 mg OE/d (placebo: PL), 400 mg OE/d (OE-400), or 800 mg OE/d (OE-800), administered in two daily doses providing a total of 8 and 16 mg HT, respectively. The exercise bout included 100 minutes of ergometer cycling at 60% VO2peak, followed by 20 minutes of treadmill running at 70%VO2peak. Plasma CK levels, muscle soreness ratings and peak isometric force (MVC) of the leg-extensors were obtained prior to the supplementation period (BL), pre-exercise, immediately post-exercise (0-PO), 2 hours post-exercise (2-PO) and 24 hours post-exercise (24-PO). A 12-day washout period separated the treatment phases, which were administered in a double-blind design. RESULTS: Following supplementation, total area under the curve (AUC) for HT was significantly greater for OE-800 versus OE-400 and PL. HT AUC was also significantly greater with OE-400 versus PL. Plasma CK levels rose significantly from pre- (273.4±310.6 U/L) to post-exercise (peak at 24-PO: 429.2±381.5 U/L). Muscle soreness also increased from pre- (14.5±9.6 mm) to post-exercise (peak at 0-PO: 50.7±20.0 mm). MVC declined significantly from pre-exercise (574.3±165.3 N) to post-exercise (0-PO: 524.0±169.7 N). No treatment*time interactions or differences in AUC were observed for muscle recovery variables. CONCLUSION: OE supplementation significantly increased plasma HT concentrations, but did not affect plasma CK levels, muscle soreness or muscle function following heavy aerobic exercise. Further study is required to determine if higher doses of OE elicit positive effects on these variables.