Abstract
The objective of this study was to analyze the performance of knee muscles in the affected and nonaffected sides of ACL patients as well as with healthy asymptomatic subjects. Fifty-four males, 27 with asymptomatic knees and 27 patients with tear in ACL were included in the study. Subjects performed concentric knee extension and flexion efforts at 60\ci/s and 180\ci/s on a Biodex isokinetic dynamometer. Isokinetic peak torque, angle to peak moment of quadriceps (Q) and hamstring (H), and hamstrings/quadriceps ratio (HQR) were measured. There was a significant decline in the mean strength of Q at 60\ci/s for the involved side compared with either the uninvolved side or with that of the healthy subjects, but not in H. There was also a significant decrease in mean Q strength at 180\ci/s of the involved side of ACL patients compared with the healthy young males. There was a significant difference in mean angle to peak moment of Q at 180\ci/s in the healthy group compared with the involved side of the patients and a significant difference for the same parameter in H at 60\ci/s in the involved compared with the healthy group and uninvolved sides of the ACL patients. There was no significant difference in hamstrings/quadriceps ratio between the groups. It was concluded that the effect of ACL tear on H strength is significantly less than that on the Q one year post-injury. Angle to peak moment offers original and practical information for the determination of individual performance in post ACL injury patients.
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