Energy of Contraction in Muscle

Abstract

A large body of the present day theory of production and absorption of work and heat by the contracting muscle is inferred from the experimental study of excised amphibian muscle at 0°. The question arises as to how well the results apply to in situ human muscles. In a study of the question, the thermodynamics of these muscles is discussed and an attempt made to evaluate directly their contraction energy characteristics. The study presumes that the muscle is analogous in some of its properties to both a mechanical spring and an electromagnet. The analogy is utilized to derive an analytical expression of the “biomechanical energy” of a body system in activity. The law of conservation of energy allows a comparison of this expression with the experimental measurement—assumed obtainable—of the “regional metabolism” of the system associated with the activity. The comparison would furnish the magnitudes of two heat coefficients which characterize the contraction energy of the in situ muscle.