Maximal voluntary muscular torque output of the quadriceps and hamstrings during isokinetic exercise was studied. Both knees of 50 male and 50 female subjects between the ages of 25 and 34 were tested at 60, 180, and 300" per second on the Cybex II isokinetic dynamometer. The means, standard deviations, ranges, absolute value differences, and analysis of variance were calculated on the torque values. The findings were that 1) torque values decreased as speed of exercise increased; 2) quadriceps torque values were significantly greater than the hamstrings at each test speed; 3) the ratio of hamstring torque values to quadriceps torque values significantly increased as the test speed increased; 4) dominant and nondominant knee torque values differed significantly for the males but not for the females; 5) the ratio of nondominant to dominant knee torque values was equal to or greater than 97% in all tests; and 6) the absolute difference in torque values between each subject's knees was 12 foot-pounds or less. J Orthop Sports Phys Ther 1981;3(2):48-56.