Dissipative processes in passive human skeletal muscle

The method of decaying oscillations of low amplitude has been used to investigate the damping properties of human skeletal muscles at rest. It is shown that the curve of attenuation of the oscillations of the limb greatly differs from the curve of the classical viscous attenuation and the work on the limb per period does not depend on frequency. It is concluded that the damping properties of the passive muscles at the rates of change in angle in the joint to 100 degree/sec are mostly connected with the resistance of the "dry friction" type not depending on the rate and amounting to ~0·07 N/cm ² of the cross-section of the muscle. For slight single stretchings at a low rate close dependence of the resistance of the muscle on the intervals between exposures was established indicating the presence in the passive muscle of marked thixotropy.