[Dependence of muscle electrical activity on its length in the development of a constant force].

Dependence of the integrated electromyogram on the muscle length with its tension being constant was investigated in human biceps muscle. The subject kept his forearm at known angles or flexed the elbow at the horizontal plain against a constant force applied to his wrist. The data obtained showed that the integrated electromyogram increased several times with muscle shortening both at static condition and during movement. Causes of increase in the electrical activity are discussed.