The aim of this study was to determine the short-term (1 session) and long-term (36 sessions) effects of various exercise training (endurance, sprint, and combined) on plasmatic indexes of muscle damages (lactate dehydrogenase, creatine kinase, and malondialdehyde). For this purpose, 40 young rats (3 months old) were randomly divided into four groups including control, endurance, sprint, and combined group (each group 10 subjects). Following the first and 36th sessions of exercise training, blood samples were gathered. To measure these variables, kits and auto analyzer apparatus were used. The data were analyzed using two-way repeated ANOVA. The results showed that 24 hours following the first session of exercise training, there was a significant increase in CK and LDH enzymes (but not MDA) in most training groups (compared to the control group). This increase was clearer after 36th session. Totally, the results indicated that both short-term and long-term exercise training resulted in muscle injuries, and the injuries were more intensive in combined group compared with the other groups. Also, given that MDA index did not significantly change among groups in more parts of the evaluation phase, although indexes of muscle injuries significantly changed. We can conclude that lipid peroxidation is not the probable mechanism of initialling muscle injury.