A THERMODYNAMIC APPROACH TO THE COMPROMISE BETWEEN POWER AND EFFICIENCY IN MUSCLE-CONTRACTION

An analysis of muscle contraction based on irreversible thermodynamics is presented in this work. From reported experimental results, it is shown that a muscle, as an energy converter, does not obey linear phen omenological relations. Some more suitable nonlinear phenomenological relations are found and discussed from an evolutionary point of view. In those relations a parameter a appears which is related to the nonli nearity of the equations. It is suggested that this parameter determin es the compromise between the power output and the efficiency reached by the muscle. By analysing the energetics of some suitable performanc e regimes, we suggest that the fact that alpha values greater than 0.4 are not found in muscles of higher species, can be interpreted as an evolutionary necessity. (C) 1997 Academic Press Limited.