Abstract
The aims of the present study were (1) to characterize the knee angles of hamstring and quadriceps peak torques at slow (60 deg/sec) and moderate (180 deg/sec) isokinetic speeds in patients with different knee ligament insufficiencies (n = 227); (2) to find out what (if any) quantitative effect the speed increase has on these peak torque angles; and (3) to determine if injury type or muscle strength has an effect on the results. For the measurements, the Cybex II dynamometer was used. In hamstrings, the mean peak torque angle was 35 deg of knee flexion, when the angular speed of the dynamometer was 60 deg/sec. At 180 deg/sec, the angle appeared 8 deg later in the range of motion, at 43 deg (p < 0.001). In quadriceps, the average peak torque angle was 54 deg at 60 deg/sec. At 180 deg/sec, the angle occurred 10 deg later, at 44 deg of knee flexion (p < 0.001). Within each injury group, there were no significant differences between the injured and uninjured limb. The type of the knee ligament injury (grade II or III anterior cruciate, medial collateral or lateral collateral ligament injury, or grade I combination injury) also did not affect the results. However, the muscle strength of the weak muscle groups (that is, hamstrings in all the other injury groups except anterior cruciate ligament group) had a significant negative correlation with the angle of peak torque. This meant that in these hamstrings, the peak torque angle occurred later in the range of motion when muscle strength decreased, and vice versa.