Preservation of bulk and strength in muscles affected by neurogenic lesions.

Mechanisms involved in maintaining bulk and strength in partially denervated muscles of patients with neurogenic lesions are discussed. Estimation of muscle fiber hypertrophy by electrophysiological examination is possible, but it depends on the construction of sampling electrodes with precise geometry. The arrangement of muscle fibers of motor units within the muscle is discussed by analogy with the four-color map problem. An experiment to measure the twitch tensions of individual motor units in man is devised; it requires the use of microprocessor control of the stimulus and recurrent measurements of the twitch forces.