(The FASEB Journal. 2008;22:753.33)
© 2008 FASEB
(The FASEB Journal. 2008;22:753.33.)
© 2008 FASEB
The influence of aging on the in vivo properties of human patellar tendon
Jared M Dickinson1,
Chad C Carroll1,
Jacob M Haus1,
Gary A Lee1,
Christopher J Hollon1,
Per Aagaard2,
S Peter Magnusson3 and
Todd A Trappe1
1 Human Performance Laboratory, Ball State University, Muncie, IN
2 Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Copenhagen, Denmark
3 Institute of Sports Medicine, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
ABSTRACT
We investigated the in vivo mechanical properties of the patellar tendon in 37 men and women (11 Young, 27±1 y; 26 Old, 65±1 y). Patella and tibial displacement were monitored with ultrasonography during ramped isometric contractions of the knee extensors and magnetic resonance imaging was used to determine tendon cross-sectional area (CSA), length, and signal intensity (SI). At maximal levels of force, deformation (15%, p=0.05), stress (23%), and strain (13%) were higher in Young compared to Old (p<0.05). However, aging did not alter the force-deformation or stress-strain characteristics of the patellar tendon. Tendon CSA (12%) and SI (24%) decreased with aging (p<0.05) but these differences were isolated to the mid-region of the tendon. Independent of age, deformation (18%), stiffness (35%), stress (41%), CSA (28%), and length (11%) were greater (p<0.05) in men compared to women. After force normalization, stress (26%) and strain (22%) were higher in women compared to men (p<0.05). Declines in quadriceps muscle function with aging are not a result of changes in patellar tendon mechanical properties. The age-associated decrease in SI indirectly suggests that the internal milieu of the tendon is altered with aging.
NIH R01 AG020532 (TT), APS Postdoctoral Initiative Award (CC)
