Purpose: This study tested the effectiveness of a fruit/berry/vegetable concentrate (FVC), Juice Plus+® supplement on muscle function and oxidative stress in response to an acute bout of eccentric exercise (EE).
Methods: Forty one (18-35 yrs) healthy volunteers were randomly assigned to either a placebo (P) or FVC treatment taking capsules for 28 days (6 day-1) prior to the EE and for the next four days. All subjects completed 4 sets of 12 repetitions of eccentric elbow flexion with their non-dominant arm. Blood, muscle soreness (MS), range of motion (ROM), and maximal isometric force (MIF) of the elbow flexors were obtained before and, immediately after exercise, and at 2, 6, 24, 48, 72 hrs post-exercise. Plasma was analyzed for creatine kinase (CK), lipid hydroperoxides (LOOH), malondialdehyde (MDA) and protein carbonyls (PC). Glutathione ratio was determined from whole blood extracts.
Results: MS, ROM, MIF and plasma CK demonstrated significant time effects independent of treatment. MS and plasma CK increased over time while ROM and MIF decreased over time. There was a significant time and time by treatment effect for plasma PC and MDA. PC and MDA increased over time in the P group (p<0.01) but were not significantly altered in the FVC treated group at any time. No significant changes were noted in LOOH. The glutathione ratio was elevated immediately post exercise in both groups (p<0.01) and elevated 6hr post exercise with P compared to the FVC treated group (p<0.05).
Conclusion: This study reports that 4 weeks of pretreatment with a FVC can attenuate blood oxidative stress markers induced by EE but had no significant impact on the functional changes related to pain and muscle damage.
© 2010 The American College of Sports Medicine