Influence of knee joint angle on muscle properties of paralyzed and nonparalyzed human knee extensors.

Abstract

Muscles of individuals with a spinal cord injury (SCI) exhibit an unexpected leftward shift in the force (torque)-frequency relationship. We investigated whether differences in torque-angle relationships between SCI and able-bodied control muscles could explain this shift. Electrically stimulated knee-extensor contractions were obtained at knee flexion angles of between 30 degrees and 90 degrees. Torque-frequency relationships were obtained at 30 degrees, 90 degrees, and optimum angle. Optimum angle was not different between groups but SCI-normalized torques were lower at the extreme angles. At all angles, SCI muscles produced higher relative torques at low stimulation frequencies. Thus, there was no evidence of a consistent change in the length of paralyzed SCI muscles, and the anomalous leftward shift in the torque-frequency relationship was not the result of testing the muscle at a relatively long length. The results provide valuable information about muscle changes occurring in various neurological disorders.

5 Figures and Tables

Cite this paper

@article{Gerrits2005InfluenceOK, title={Influence of knee joint angle on muscle properties of paralyzed and nonparalyzed human knee extensors.}, author={Karin H. L. Gerrits and Constantinos N. Maganaris and Steven J Brown and Anthony Sargeant and David A Jones and Arnold de Haan}, journal={Muscle & nerve}, year={2005}, volume={32 1}, pages={73-80} }