The effect of varied hip angles on the generation of internal tibial rotary torque

Previous researchers have determined that 90° of knee flexion is an appropriate angle to condition the internal tibial rotators. Because the majority of internal tibial rotators are two-joint muscles crossing both the knee and the hip, the influence of the hip angle on the generation of rotary torque was examined. The purpose of this study was to investigate the effect of four hip angles on the generation of internal tibial rotational torque with the knee positioned at 90° of flexion. Forty subjects, 20 males and 20 females, were tested at four positions of hip flexion (120°, 90°, 45°, 10°) using a modified Cybex II isokinetic dynamometer, and their maximal mean internal rotary torque values were recorded. The subjects were placed in a custom-made orthotic-type boot to minimize the motions of the talo-calcaneal joint. Sixty percent of the males and 65% of the females generated their greatest absolute torque value at 120° of hip flexion. A procedure investigating the rankings of the maximal mean torque values at each of the tested hip positions revealed a significant difference between the hip positions of 120 and 10° for both populations (P