Dependence of the dynamic speckle field spectral parameters on the force of isometric contraction of human skeletal muscle

The results of an experimental study of the effect of vibrational motion of human skeletal muscles on the intensity fluctuating spectrum of the dynamic speckle field scattered by the skin are reported. It has been found by experiment that the area under the spectral curve of the speckle-optical myogram increases in proportion to the applied isotonic load until it reaches 80% of the maximum effort of the patient's brachial biceps. Further increase in isotonic load up to the maximum effort leads to a decrease in the vibrational activity of the muscle. Comparative analysis with electromyographic data has shown that traditional method fail to register this change.