This study tested the development of oxidative stress and the effects of antioxidant supplementation in an 80-km ride. A precompetition survey revealed that no competitor would participate without vitamin E supplementation; therefore, 46 horses were paired for past performances and randomly assigned to two groups of 23 each for 3 wk of supplementation before the ride. One group (E) was orally supplemented with 5,000 IU of vitamin E per day; the other group (E+C) received that dose of vitamin E plus 7 g/d of vitamin C. Blood samples, temperature, and heart rate were taken the day before the race, at 21 and 56 km during the ride, at completion, and after 20 min of recovery. Plasma was assayed for lipid hydroperoxides, alpha-tocopherol, total ascorbate, albumin, creatine kinase (CK), and aspartate aminotransferase (AST). Total glutathione and glutathione peroxidase activity were determined in red blood cells and white blood cells. Thirty-four horses completed the race, 12 horses (six in E and six in E+C) did not finish for reasons including lameness, metabolic problems, and rider option. Plasma ascorbate was higher (P = 0.045) in the E+C group than in the E group. Other than ascorbate, neither antioxidant status nor CK and AST activities were affected by supplementation with E+C vs. E. Red blood cell glutathione peroxidase, white blood cell total glutathione, lipid hydroperoxides, CK, and AST increased, and red blood cell total glutathione and white blood cell glutathione peroxidase activity decreased with distance (P < 0.001). Positive correlations were found for plasma lipid hydroperoxides on CK (r = 0.25; P = 0.001) and AST (r = 0.33; P < 0.001). These results establish an association between muscle leakage and a cumulative index of oxidative stress.

No abstract

This study tested the development of oxidative stress and the effects of antioxidant supplementation in an 80-km ride. A precompetition survey revealed that no competitor would participate without vitamin E supplementation; therefore, 46 horses were paired for past performances and randomly assigned to two groups of 23 each for 3 wk of supplementation before the ride. One group (E) was orally supplemented with 5,000 IU of vitamin E per day; the other group (E+C) received that dose of vitamin E plus 7 g/d of vitamin C. Blood samples, temperature, and heart rate were taken the day before the race, at 21 and 56 km during the ride, at completion, and after 20 min of recovery. Plasma was assayed for lipid hydroperoxides, alpha-tocopherol, total ascorbate, albumin, creatine kinase (CK), and aspartate aminotransferase (AST). Total glutathione and glutathione peroxidase activity were determined in red blood cells and white blood cells. Thirty-four horses completed the race, 12 horses (six in E and six in E+C) did not finish for reasons including lameness, metabolic problems, and rider option. Plasma ascorbate was higher (P = 0.045) in the E+C group than in the E group. Other than ascorbate, neither antioxidant status nor CK and AST activities were affected by supplementation with E+C vs. E. Red blood cell glutathione peroxidase, white blood cell total glutathione, lipid hydroperoxides, CK, and AST increased, and red blood cell total glutathione and white blood cell glutathione peroxidase activity decreased with distance (P < 0.001). Positive correlations were found for plasma lipid hydroperoxides on CK (r = 0.25; P = 0.001) and AST (r = 0.33; P < 0.001). These results establish an association between muscle leakage and a cumulative index of oxidative stress.

The purpose of this study was to examine changes in performance and metabolic parameters in collegiate soccer players during preseason preparation and to determine the impact of a nutraceutical blend proposed to reduce oxidative stress. Male Division I college soccer players (n = 22) performed a progressive maximal treadmill test at the beginning and end of preseason to assess changes in Vo2max, velocity at lactate threshold (VLT), time-to-exhaustion, lipid hydroperoxide (LPO), 8-isoprostane, and creatine kinase (CK) response. After baseline testing, athletes were randomly assigned to receive the nutraceutical blend (EXP; n = 12) or an isocaloric equivalent (CON; n = 10) for 20 days of preseason training. DeltaVo2max (2.1 +/- 3.3 ml.kg.min, p = 0.007), DeltaVLT (0.8 +/- 1.4 km.h, p = 0.045), and Deltatime-to-exhaustion (39.4 +/- 77.4 seconds, p = 0.033) were improved across groups, but a significant effect of supplementation on performance was not seen. Changes in resting levels of CK from the beginning to end of preseason were significantly lower (p = 0.044) in EXP (64.8 +/- 188.4 U.L) than in CON (292.8 +/- 304.8 U.L). Additionally, EXP demonstrated a significant decrease in the magnitude of the 8-isoprostane response at Trial 2 compared with Trial 1 (effect size [ES] = -0.74), whereas CON had an increased response (ES = 0.20). A similar pattern was seen for LPO (p = 0.067). Preseason training in male college soccer players resulted in significant improvements in Vo2max, VLT, and time-to-exhaustion. Supplementing with a proprietary antioxidant and nutraceutical blend may enhance some of these effects as indicated by magnitude of the responses. However, it appears that the most notable effects of supplementation were seen for reduced CK and oxidative stress, at least with short-term supplementation.

No abstract