THE RELATION BETWEEN FORCE, VELOCITY AND MECHANICAL POWER IN HUMAN MUSCLE

Abstract

For better understanding of the human movement it should be needed to know the physiological and mechanical characteristics of muscle itself. On the mechanical properties of the muscle, Hill (1922) first initiated a concept of "viscosity". This concept was derived from his experiment on human arm muscle by using an "inertia wheel", in which he observed a linear relationship between the mechanical work done and the time consumed in the arm movement. Fenn and Marsh (1935) found the relation between force and velocity being non-linear. In 1938, from an extensive thermal measurement on the frog muscle, Hill derived an simple hyperbolic equation relating to force exerted and velocity developed:(P+a) V= b(P_0- P) where P is force, V is velocity of shortening, P_0 is the isometric tension, and both a, b are constants. He suggested that the constants should be similarly determined by either the mechanical or the thermal measurement. But his further study (1964) showed that the constants derived from thermal measurbment could not be the same as that determined mechanically, although the tendency should be the same. Dern et al (1947) first tried to test Hill's equati6n on the human muscle by applying inertia as the load. However, their experimental result involved some cases underrepresented by Hill's equation. By using the weight, Wilkie (1950) found that Hill's characteristic equation was well applicable to the human muscle, and proposed a simple but nice model of muscle. Ralston (1949) also confirmed its applicability on the patients having cineplastic muscle tunels. Our previous study (1966) was primarily concerned with the mechanical power developed against the load provided by an inertia wheel. The present study was designed to examine the relation between force, velocity and mechanical power of the muscle by using the elbow flexors of adult males and females Experimental procedure was basically the same as a part of Wilkie's experiment (1950). Hill's characteristic equation was intended to apply to the data collected.