The purpose of this study was to determine the effect of interval sprint exercise and a detraining period on lipid peroxidation (MDA) and the response of antioxidant system (FRAP, uric acid, bilirubin and total protein). For this purpose, 35 male rats were divided randomly into two groups: sprint group (experimental) (n=20) and control group (n=15, without any training). Experimental group trained for 12 weeks, 3 sessions per week with given intensities (five trained rats experienced the detraining so that the effects of detraining could be studied from 8th to 12th week). During our experiments, animals were individually housed in a climate-controlled (temperature and humidity) animal laboratory. They had 12:12 hours of light-dark cycle as well as standard rat chow. MDA and FRAP were measured manually while other measurements were performed by a kit. Data were analyzed by two-way repeated ANOVA. The results showed a significant difference between two groups in MDA (P=0.022), FRAP (P=0.005) and bilirubin (P=0.002), durig at least one of the evaluation periods while total protein and uric acid remained unchanged. In the experimental group, indeed, there was a significant difference among various assessments in MDA (P=0.001), FRAP (P=0.001), bilirubin (P=0.008) and uric acid (P=0.012). Generally, this protocol of sprint exercise causes an adaptation of antioxidant system and lipid peroxidation, but detraining reverses these results.