The effect of 30-m repeated sprint exercise on muscle damage indicators, serum insulin-like growth factor-Iand cortisol

The purpose of this study was to examine the effects of arepeated sprint exercise protocol on muscle damage indicators, serum IGF-Iand cortisol levels. Nine trained male subjects (age 23.3 ± 3.6 years) completed arepeated sprint protocol consisting of two sets of 10 × 30-m maximal sprints with 30 s of active recovery between sprints and 5 min of passive recovery between sets. The isometric strength and flexibility were measured before, immediately after and 24 hours after exercise. 30-m maximal sprint time was measured before and 24 hours after exercise. Blood samples were taken before, immediately after and 24 hours after exercise. Isometric strength and flexibility were significantly decreased after exercise and 24 hours after exercise (p < 0.05). 30-m sprint time was significantly increased 24 hours after exercise (p < 0.05). Asignificant increase in serum lactate dehydrogenase, IGF-Iand cortisol were found after exercise (p < 0.05). Serum creatine kinase increased significantly immediately after and 24 hours after exercise compared to pre-exercise values (p < 0.05). Our data show that due to increased serum IGF-Ilevel, repeated sprint exercise may have anabolic effects as well as traumatic effects on the muscles.