Adaptations to strength training differ between endurance-trained and untrained women

Purpose The purpose of this study was to investigate if endurance athletes, sustaining their normal endurance training, experience attenuated adaptations to strength training compared to untrained individuals. Methods Eleven non-strength-trained female endurance athletes (E + S) added 11 weeks of strength training to their normal endurance training (5.1 +/- 1.1 h per week), and 10 untrained women (S) performed the same strength training without any endurance training. The strength training consisted of four leg exercises [3 x 4 - 10 repetition maximum (RM)], performed twice a week for 11 weeks. Results E + S and S displayed similar increases in 1RM one-legged leg press (E + S 39 +/- 19%, S 42 +/- 17%, p < 0.05), maximal isometric torque in knee extension (E + S 12 +/- 11%, S 8 +/- 10%, p < 0.05) and lean mass in the legs (E + S 3 +/- 4%, S 3 +/- 3%, p < 0.05). However, S displayed superior increases in peak torque in knee extension at an angular velocity of 240 degrees sec(-1) (E + S 8 +/- 5%, S 15 +/- 7%, p < 0.05) and maximal squat jump height (E + S 8 +/- 6%, S 14 +/- 7%, p < 0.05). Conclusions In this study, concurrent training did not impair the adaptations in the ability to develop force at low contraction velocities or muscle hypertrophy. However, concurrent training attenuated strength training-associated changes in the ability to develop force at higher muscular contraction velocities.