Cruciate Ligament Loading During Isometric Muscle Contractions

Abstract

A model of the knee in the sagittal plane was used to investigate the ligament forces resulting when an ex ternal load applied to the tibia resisted either extension or flexion of the knee under increasing isometric quad riceps or hamstrings contractions, respectively. An el ementary mechanical analysis showed which ligament, the anterior or posterior cruciate, was loaded at a given flexion angle and known line of action of the external load. Ligament force, as a proportion of the external load, was also calculated. The results serve as guide lines for the design of injury-specific physical therapy techniques for use after cruciate ligament reconstruc tion.