Adaptation of mechanical properties of muscle to high force training in man.

The first dorsal interosseus muscle of the hand was trained for 8 weeks using eighty maximal 10 s voluntary isometric contractions per day. As a result of this training the maximal voluntary force increased by 33%, but electrically evoked tetanic tension increased by only 11%. In other subjects the muscle was trained using electrical stimulation at 60 Hz to evoke eighty maximal 10 s tetani per day for 8 weeks. This training produced no increase in maximum voluntary force. Our results show that the increase in maximal voluntary force under these conditions may be due to a change in the voluntary neural drive to the muscle.