Torque Characteristics of the Quadriceps and Hamstring Muscles during Concentric and Eccentric Loading.

Additional fundamental information is needed on the effects of speed and dominant limb on torque values and ratios of the quadriceps and hamstring muscles during both eccentric and concentric contractions. The purpose of this study was to determine the dominant leg's peak isokinetic torque production of male college athletes. One hundred subjects, from 18 to 25 years of age, were tested on a Biodex B-2000 isokinetic dynamometer concentrically at 60, 120,300, and 450 degrees /sec and eccentrically at 60 and 120 degrees /sec. All data were analyzed by means of a repeated measures analysis of variance to determine if significant differences (p < 0.01) existed. Concentric torque production of the quadriceps and hamstring muscles decreased significantly (p < 0.01) as the angular velocity increased. No significant differences (p > 0.01) existed between the quadriceps or hamstring muscles' eccentric torque production at 60 and 120 degrees /sec. Torque production of the quadriceps and hamstring muscles was significantly greater (p < 0.01) during eccentric than concentric loading at 60 and 120 degrees /sec. Concentric hamstring/quadriceps ratios increased significantly (p < 0.01) as the angular velocity increased. Hamstring/quadriceps ratios were significantly greater (p < 0.01) during eccentric than concentric loading at 60 and 120 degrees /sec. These findings are important when establishing testing, rehabilitation, and conditioning techniques for athletes who participate in various high-speed loading conditions during concentric and eccentric muscle contractions. J Orthop Sports Phys Ther 1991;14(4):149-154.