Investigation of the effects of an acute bout of isokinetic exercise on DNA damage in active male subjects

Purpose: Isokinetic exercise is used to reduce strength imbalance and to enhance performance. Although previous studies presented alterations on DNA induced by different exercise types; effects of isokinetic exercise on DNA remain unknown. Present study was designed to explore the time course of possible DNA damage following an acute bout of isokinetic exercise. Materials and Methods: 11 healthy, male, active subjects (mean age 19.45±0.31, Body mass index 22.05±0.51) were enrolled. They performed eccentric contractions of knee flexors and extensors with dominant leg on a dynamometer (Humac Norm Testing Rehabilitation system, CSMI Medikal Solutions, USA). Isokinetic hamstring, quadriceps strength were recorded at eccentric (30, 120°s-1) angular velocities. Blood was obtained before, after and 2 days following the exercise. DNA damage was measured by Comet analysis. Friedman test was used for statistical analysis, p≤0.05 was considered statistically significant. Results: In terms of DNA damage parameters following isokinetic exercise tail length (18.76±3.08 vs. 16.21±1.14; p=0.027) was significantly decreased, whereas it was increased again on the 2nd day following the exercise compared to the post-exercise value (16.21±1.14 vs.18.33±1.23; p=0.011). Conclusion: Decreased tail length immediately after exercise suggests that the applied isokinetic exercise may positively influence genotoxicity. This favorable effect returns within 2 days