Oxidative-Stress, Muscle Forces/Soreness Responses To Eccentric Exercise: Fruit/Vegetable Concentrate Compared To Placebo.

Abstract

PURPOSE: This study was designed to test the efficacy of a fruit/vegetable concentrate (FVC) supplement on oxidative stress, muscle force/work, and muscle soreness (MS) to an acute bout of eccentric exercise (EE) compared to a placebo. METHODS: Forty (18-35 yrs) healthy volunteers were randomly assigned to either a (FVC) or placebo (P) double blind treatment. The subjects took capsules for 28 days (24 days prior to the EE and for the next four days) with compliance=97.5% FVC; 98.5% P. Subjects arrived in the morning, a resting blood sample was obtained and maximal isometric forces (MIF), and MS (on both arms) were determined prior to the EE (4 sets of 12 repetitions of elbow flexion with their non-dominant arm {ND}). Blood, MIF, and MS were also obtained immediately after EE, 2, 6, 24, 48, and 72 hrs post-exercise. Protein carbonyls (PC), lipid hydroperoxides (LH), and creatine kinase (CK) were determined from plasma. RESULTS: Total work for the EE was similar for the P=1636.2 ±172.9 J and FVC=1784.4 ±174.4 J. The % decline in work was similar across treatments {1st set to 4th set for the EE=35.3 ±4.2% (P) and 31.7± 3.7% (FVC)}. MIF decreased immediately post EE for the ND {35.9% ± 4.0 (P) vs. 31.1% ± 3.2 (FVC)} reaching its nadir at 2h hrs post EE. CK increased over time and peaked at 72 hrs after EE (292.0±64.6 IU (P); 240.8 ±66.9 IU (FVC) with no difference across treatments. LH did not demonstrate any changes across time or treatment. PC increased over time (p< 0.001) with no time x treatment effect. PC were similar across treatment prior to and immediately post EE. PC increased 2hr post EE in the P group and increased over time with a peak at 48 hrs post EE (0.52 nmol.mg protein-1). PC were significantly lower in the FVC treatment compared to P (p <0.034) from 2hr post time through 72 hr post EE. CONCLUSIONS: The data indicates that four weeks of pre-supplementation and continued treatment after EE with a fruit/vegetable concentrate had no apparent effect on the muscle forces and MS but attenuated blood oxidative stress compared to placebo treatment as indicated by protein carbonyls. Supported by a grant from NSA.