The aim of this study was to evaluate the effect of exercise on apoptosis in rat gastrocnemius and soleus muscle tissue and to determine the effect of meloxicam, a novel non-steroidal anti-inflammatory drug (NSAID), on the ratio of exercise-induced apoptosis. Forty male Wistar rats were used in the experiments. Spontaneous wheel-running was used as an exercise protocol. Rats were divided randomly into four groups. Group A (n = 10) was the control group, in which rats did not perform any exercise. In group B (n = 10), gastrocnemius and soleus muscles were biopsied immediately after exercise. The rats in group C (n = 10) were placed back in their cages after exercise and allowed to rest for 48 It, after which the gastrocnemius and soleus muscles were biopsied. In group D (n = 10), rats were given 11 mg meloxicam (Mobic, Boehringer Ingelheim) per kilogram body weight per day p.o. for 2 days, after which gastrocnemius and soleus muscles were biopsied 48 h after exercise. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick end labelling (TUNEL) technique was used to detect DNA fragmentation in situ. TUNEL-positive nuclei were identified and counted. The apoptosis ratio in gastrocnemius muscle was 0.50x10(-3) +/- 0.96x10(-3); in group A, 5.42x10(-3) +/- 3.58x10(-3) in roup B, 3.55x10(-3) +/- 3.23x10(-3) in Group C and 3.52x10(-3) +/- 1.00 in Group D; the ratios in soleus muscle were 0.98x10(-3) +/- 1.83x10(-3) 3.03x10(-3) +/- 2.78x10(-3), 4.48x10(-3) +/- 3.32x10(-3) and 2.91x10(-3) +/- 1.98x10(-3), respectively. The differences between the apoptosis ratios in group A and B, Group A and C, and Group A and D were statistically significant (P < 0.05). There was no statistically significant difference between Croup C and D. In conclusion, exercise increased apoptosis in gastrocnemius and soleus muscle tissue, and the apoptosis ratios were not affected by meloxicam.