Isokinetic elbow flexion and coactivation following eccentric training

The influence of an eccentric training on torque/angular velocity relations hips and coactivation level during maximal voluntary isokinetic elbow flexi on was examined. Seventeen subjects divided into two groups (Eccentric Grou p EG, n = 9 Control Group CG, n = 8) performed on an isokinetic dynamometer , before and after training, maximal isokinetic elbow flexions at eight ang ular velocities (from - 120 degrees s(-1) under eccentric conditions to 240 degrees s(-1) under concentric conditions), and held maximal and submaxima l isometric actions. Under all conditions, the myoelectric activities (EMG) of the biceps and the triceps brachii muscles were recorded and quantified as the value. Eccentric training of the EG consisted of 5x6 eccentric musc le actions at 100 and 120% of one maximal repetition (1RM) for 21 sessions and lasted 7 weeks. In the EG after training, torque was significantly incr eased at all angular velocities tested (ranging from 11.4% at 30 degrees s( -1) to 45.5% at - 120 degrees s(-1)) (p < 0.05). These changes were accompa nied by an increase in the RMS activities of the BE muscle under eccentric conditions (from - 120 to - 30 degrees s(-1)) and at the highest concentric angular velocities (180 and 240 degrees s(-1)) (p < 0.05). The RMS activit y of the TB muscle was not affected by the angular velocity in either group for all action modes. The influence of eccentric training on the torque ga ins under eccentric conditions and for the highest velocities was attribute d essentially to neural adaptations. (C) 1999 Elsevier Science Ltd. All rig hts reserved.