The tensile and stress relaxation responses

of human patellar tendon varies

with specimen cross-sectional area.

J. Biomechanics. 32(9):907-914, 1999.

Atkinson, TS, Ewers, BJ, Haut, RC.

Abstract

In order to provide insight into the mechanical response of the collagen fascicle structures in tendon, a series of constant strain rate and constant displacement, stress relaxation mechanical tests were performed on sequentially sectioned human patellar tendon specimens (protocol 1) and specimens with both small (~1 mm²) and large (~20 mm²) cross-sectional areas (protocol 2). These data described the stress relaxation and constant strain rate tensile responses as a function of cross-sectional area and water content. The experimental data suggested that small portions of tendon exhibit a higher tensile modulus, a slower rate of relaxation and a lower amount of relaxation in comparison to larger specimens from the same location in the same tendon. The decrease in relaxation response and the increase in tensile modulus with decreasing cross-sectional area was nonlinear. These data suggest that there may be structures other than the subfascicle, such as the epitenon and other connective tissue components, which influence the tensile and stress relaxation responses in tendon.

Orthopaedic Biomechanics Laboratories,

College of Osteopathic Medicine,

Michigan State University,

East Lansing, Michigan 48824

Please address correspondence to:

Roger C. Haut, Ph.D.,

Orthopaedic Biomechanics Laboratory,

College of Osteopathic Medicine,

A414 East Fee Hall,

Michigan State University,

East Lansing, MI 48824,

Tel: (517)355-0320,

Fax: (517)353-0789,

E-mail: haut@msu.edu