Predicting red muscle performance

Abstract

Abstract The active force production during contraction of bundles of red muscle fibres from myotomal muscle of dogfish Scyliorhinus canicula (L.) has been predicted by a numerical model based on Hill's 2-component model of the mechanical properties of muscle, with the addition of a simple model for the kinetics of activation. When all of these factors are included, the model makes good predictions for the force and power during stimulation. There are, however, significant discrepancies during relaxation after the end of stimulation, from which we conclude that additional processes have a large influence on force during relaxation. This has functional relevance for fish swimming because during relaxation the muscle fibre continues its sinusoidal pattern of movement and thus continues to either produce power if shortening, or require power input from other structures to cause lengthening.