Analysis of cumulative strain in tendons and tendon sheaths.
Goldstein SA; Armstrong TJ; Chaffin DB; Matthews LS
J Biomech 1987 Jan; 20(1):1-6
Tests were carried out to determine the viscoelastic properties of tendons and tendon sheaths under simulated physiological loading conditions, using a newly developed method to measure tendon strain. The study was carried out in 25 frozen flexor digitorum profundus tendons from 12 intact cadaver hands belonging to four females and three males, aged 55 to 72 years, which were subjected to uniaxial step stress and cyclic loads. The interactions of the tendon, tendon sheath, and retinacula were determined using newly designed clip strain transducers attached on tendons proximal and distal to an intact carpal tunnel. The assumption was made that total stress consisted of a viscous component and an elastic component, and that during physiological applications, the viscous components were negligible as compared to the elastic components. The results obtained revealed that the elastic and viscous responses of the tendon composite fitted fractional power functions of stress and time, respectively. The significant decrease in strain which was evident from the proximal to the distal segment of the tendon was dependent on deviation of the wrist. Creep strain was related to sex and wrist position. The authors conclude that the results provide evidence that creep strain in collagenous tissues may play an important role in the etiology of cumulative trauma disorders, and they suggest further studies to develop recommendations regarding changes in the use patterns of these tissues.
NIOSH-Publication; NIOSH-Grant; Physiological-stress; In-vitro-studies; Physiological-measurements; Viscosity; Elastic-properties; Humans; Measurement-equipment; Biomechanics; Musculoskeletal-system; Sex-factors
Journal of Biomechanics
Industrial Engineering University of Michigan 2260 G G Brown University Ann Arbor, Mich 48105