Effects of antioxidant supplementation on oxidative stress and muscle injury in elite female swimmers after a strenuous training period

Reactive oxygen species [ROS] are produced due to prolong and intensive exercises, such as intense swimming training, leading to cell injury. Antioxidant supplementation seems to reduce exercise-induced oxidative stress. This study aimed to investigate the effects of antioxidant ? vitamin-mineral ? supplementation on oxidative stress and muscle injury indices after a strenuous training period in elite female swimmers. Twenty-four elite female swimmers [aged 12.93 +/- 1.22 years, weight 45.80 +/- 10.39 Kg, height 153.1 +/- 12.9 cm], members of Tehran and Karaj Swimmimg Clubs, volunteered to participate in this study. They were randomly divided into two groups: a vitamin-mineral-supplemented [n=12] and a control [n=12] group. Both groups participated in streneous swimming sessions for a period of 4 weeks [3 times a week, each time swimming 3.5 to 4 km]. Blood samples were taken before and after the period to determine muscle injury indices, such as aspartat aminotransferase [AST], creatine kinase [CK], lactate dehydrogenase, and myoglobin, as well as malon dialdehyde [MDA]. In addition, 100m crawl records were determined at the beginning and at the end of the period. Paired sample and independent t- tests were used for data analysis. Results showed that some of the muscle injury indices, namely, CK and AST, decreased significantly in the vitamin-mineral-supplemented group [p=0.011 and 0.04, respectively]. The decrease in MDA was not statistically significant. Inter-group comparisons showed a difference only with regard to CK [p=0.021]. No significant differences [intra- and inter-group comparisons] were observed in swimming performance. ROS affects exercise-induced muscle injury indices. Vitamin-mineral supplementation can have a beneficial role in such injury