MUSCLE SERIES ELASTICITY: THEORETICAL AND EXPERIMENTAL CONSIDERATIONS

Abstract

Muscle series elasticity is easy to measure, but hard to associate with specific structures. It affects the length and rate of change in length of the contractile elements, provides possibilities for storage of elastic energy, and has been associated with energy saving mechanisms during movement. External tendons are clearly in series with the contractile machinery of the muscle, while aponeuroses are not. Aponeuroses have been implicitly or explicitly modeled as, or associated with, series elastic elements of the muscle’s contractile machinery. However, theoretical models that enforce isovolumetricity clearly reveal that aponeuroses cannot be considered in series with muscles or tendons. Experimental results confirm the theoretical conclusions and show that assuming aponeuroses to be part of the series elasticity of muscles over-estimates energy storage and metabolic cost savings.