Quadriceps torque curve pattern in patients with anterior cruciate ligament injury.

We measured torque curve pattern and quadriceps muscle strength with the knee slightly flexed in 48 patients with an anterior cruciate ligament injury, and analyzed the factors associated with reduced quadriceps strength. Strength was measured under isokinetic contraction, and concentric and eccentric contractions were studied. Strength was significantly lower in the injured knee, which also showed abnormal patterns of torque curve. In addition to the rapid downward slope pattern usually associated with concentric contraction, there was a concave pattern during eccentric contraction.