Influence of Hip Position on Electromyographic and Torque Productions in the Knee

in Journal of Sport Rehabilitation
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The effects of hip position on thigh electromyographic (EMG) activity and knee torque were evaluated. Twenty-four recreational athletes (12 males and 12 females) volunteered to participate. Subjects were tested isokinetically at 30°/s in sitting and supine positions both concentrically and eccentrically during knee flexion and extension. Gravity-corrected torques (N·m) were obtained for all tests. EMG amplitude (mV) was collected via surface electrodes. Torque values were significantly greater (p<.05) for knee flexion in the sitting position when compared to the supine. EMG activity did not change relative to hip position but typically increased (p<.05) during concentric trials. Knee extension torque and EMG activity did not change during sitting or supine positions. Results indicated that the sitting position had statistically significant advantages over the supine position for producing greater hamstring torque and maintaining similar levels of EMG output during isokinetic knee flexion.

Black is with Rappahannock General Hospital, Kilmarnock, Virginia. Woodhouse is with the Exercise Science Laboratory at Norfolk State University and the Department of Orthopedics at Eastern Virginia Medical School, Norfolk, Virginia. Suttmiller is with Norfolk City Schools, and Shall is with the Department of Orthopedics, Eastern Virginia Medical School. Request reprints from Scott Black, P. O. Box 492, Irvington, VA 22480.