Effects of enforced exercise on biomechanical properties of the anterior cruciate ligament of bipedal rats.
The purpose of this study was to evaluate the effect of enforced exercise on the biomechanical properties of the anterior cruciate ligament (ACL) in bipedal rats. These rats were divided into two groups: (1) bipedal rats without exercise, E(-)G, and (2) bipedal rats with exercise for 4 weeks, E(+)G. Strength (the maximum load that can be sustained by specimen prior to rupture) results for E(+)G were significantly lower than those for E(-)G at the loading rates of 8.3 mm/sec and 1 x 10(3) mm/sec. Stiffness (the slope of the load-deformation curve for a specimen with a linear-deformation relationship) results for E(+)G were significantly lower than those for E(-)G at the rate of 8.3 mm/sec. A load relaxation test (a test of viscoelastic behavior characterized by a decrease of load in a specimen with time under a constant load or deformation) showed a larger load-relaxation phenomenon (a decline in load over time under a constant deformation) in E(-)G. Analyzing these results by a three-element model, we found that the viscosity was higher in E(+)G than in E(-)G. This study offers insight into the effects of exercise on the ACL of humans.
Sakuma
K
K
Department of Orthopedic Surgery, Kumamoto University School of Medicine, Japan.
Mizuta
H
H
Takagi
K
K
Takashima
K
K
D000818:Animals; D001696:Biomechanical Phenomena; D004548:Elasticity; D005260:Female; D007719:Knee Joint; D008023:Ligaments, Articular / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014783:Viscosity