THE EFFECT OF VALVE HANDWHEEL TYPE, OPERATING PLANE, AND GRASPING POSTURE ON PEAK TORQUE STRENGTH OF YOUNG MEN AND WOMEN

An experiment was designed to assess the factors affecting the operati on of valve handwheels. Forty volunteers (20 men and 20 women) partici pated in this study. A nested-factorial experimental design was employ ed. Handwheel type (smooth, curved, or knurled rim), operating plane ( sagittal, frontal, or transverse plane), grasping posture (power or pr ecision grasp), and operating direction (clockwise or counterclockwise ) were found to have significant effects on the (maximum volitional to rque exertion [MVTE]). A power grasp exerted more force than did a pre cision grasp. A smooth-rim handwheel oriented in the frontal plane res ulted in the least MVTE. Counterclockwise torque exertion was signific antly greater than clockwise torque exertion, but the difference was n ot very large. MVTE for women (7.9 Nm) was about 66% of that for men ( 12.0 Nm).