MEASUREMENT OF MUSCLE AND TENDON STIFFNESS IN MAN

Human first dorsal interosseous muscle was stimulated tetanically usin g several levels of percutaneous electrical current which produced for ces in the muscle-tendon complex of between 30% and 100% of maximum. D uring the tetanus the muscle was subjected to a small fast stretch. Th e ratio of the force response to the displacement of the muscle-tendon complex gave a measure of the stiffness of the total complex. An adap tation of the method of Morgan (1977) allowed the stiffness to be sepa rated into two components the stiffness of the muscle fibres and the s tiffness of the tendon. The results showed that at full activation the stiffness of the muscle fibres and the tendon are approximately the s ame. The normalised stiffness values obtained in the experiments compa red well with animal data.