In this study, we aimed to compare the effects of a single bout of acute moderate and strenuous running exercise on the production of interleukin-17 (IL-17), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra) and inflammatory response of skeletal muscles in regularly trained rats. Eight week old rats were trained by treadmill running 5 days per week for 13 weeks at the durations of 30 min (moderate) and 60 min (strenuous). Two days after the last training session, the animals were subjected to a single bout of moderate or strenuous exercise and serum samples were analyzed for IL-17, IL-6, IL-1ra levels and myeloperoxidase (MPO) activity of gastrocnemius muscle were determined. IL-17 level significantly increased in strenuous exercise group when compared to that of sedentary controls (p < 0.01), On the other hand, only in the moderate exercise group, there was a negative correlation between IL-6 and IL-17 levels (r = 0.857 and p = 0.014). In conclusion, acute single bout of strenuous exercise increased IL-17 production in trained rats and, this cytokine may be involved in inflammatory process of skeletal muscles.