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Background and Objective: Physical activities affect on antioxidative pathway. Varity, period and intensity of activities are important in health improvement. This study was carried out to determine the effect of short and medium periods of high intensities aerobic training on serum level of superoxide dismutase (SOD) and Catalase (CAT) enzymes in female rats. Methods: In this experimental study, 45 Sprague Dawley female rats were randomly allocated into control, short (4 weeks) and medium (8 weeks) of high intensities aerobic training groups. The exercise program was performed on 5 session in each week with speed of 10-17 meters per minute in slope range (5