Hysteresis

Materials exhibit hysteresis if their length-tension characteristics differ during loading (imposition of an external force) and unloading.

This passive length-tension curve, with its differing loading and unloading "arms," is modified from one published in a study of the viscoelastic behavior of rabbit tibialis anterior muscle (Taylor, Dalton, Seaber, & Garrett, 1990).

hysteresis loop

While a length-tension curve illustrates hysteresis, the curve's appearance depends on the way the tissues' length or tension is changed over time. This time course of change may be studied in two ways:

1. by holding the tissue at a constant length and observing change in the force that develops in the tissue.

A graph nearly identical to this one demonstrates force relaxation in Magnusson and colleagues' (1996) study of hamstring muscles.

2. by holding the tissue at a constant force or tension and observing changes in its length.

References: Magnusson, S.P., Simonsen, E.B., Aagaard, P., & Kjaer, M. (1996). Biomechanical responses to repeated stretches in human hamstring muscle in vivo. American Journal of Sports Medicine, 24, 622-628.

Rodgers, M.M., & Cavanagh, P.R. (1984). Glossary of biomechanical terms, concepts, and units. Physical Therapy, 64, 1886-1902.

Taylor, D. C., J. D. Dalton, A. V. Seaber, & W. E. Garrett. (1990). Viscoelastic properties of muscle-tendon units: The biomechanical effects of stretching. American Journal of Sports Medicine, 18, 300-309.

Last updated 1-12-00 Dave Thompson PT