Physiological Tremor

he contraction of a voluntary muscle is accompanied by tremors of the muscle in the form of minute oscillations. In an electrical recording of the muscle's activity the tremor can be seen as a trace of very fine rhythmic movements superimposed on the record of the contraction itself. The amplitude of the oscillations is about a hundredth or a fiftieth as large as that of the total movement produced by the contraction, and the predominant frequency, in man, is about 10 cycles per second. This rippling of the muscle, known as physiological tremor, was discovered many years ago to be a normal accompaniment of the voluntary muscles' activity. Various explanations were proposed. There were theories that the factor generating the tremor might be the heartbeat or the