ABSTRACT OSTERNIG, LOUIS R., BARRY T. BATES, and STANLEY L. JAMES. Patterns of tibial rotary torque in knees of healthy subjects. Med. Sci. Sports Exercise. Vol. 12, No. 3, pp. 195–199, 1980. Discrepancies in measures of active tibial rotation have been attributed to methodological variability and failure to adequately control accompanying foot and thigh motion. The purpose of this study was to assess maximum active tibial rotation on twenty-eight males utilizing a technique designed to stabilize the foot and thigh. Eversion and inversion motions of the talocalcaneal joint were controlled by means of a special boot connected to an isokinetic dynamometer modified with a position potentiometer. The results revealed symmetry between contralateral limbs with mean total ranges of motion of 57° and 59° for the right and left legs, respectively when tested and 90° of knee flexion and 50° at 45° of flexion. Converting these data to internal and external rotary components disclosed significant discrepancies (21–38%) between two methods applied to determine rotary neutral position. No significant differences were found between contralateral limbs for maximum torque development at all positions measured. Both range of motion and torque were found to be less at 45° of knee flexion when compared to the 90° position. Force data showed that all subjects consistently generated 90–100% of their peak torque within the initial 5–10° of active rotation and sustained relatively high torque values throughout an additional 15–20° before sharply reducing force magnitudes. These data support the concept of “wind up” effect of the medial and lateral hamstring muscles contributing to the rapid development of torque. Symmetrical patterns of contralateral limbs in torque and range of motion indicate that post-surgical comparisons with the unoperated limb to assess certain functional states of the knee may be reasonably accurate.