Authors: Ting Xia; Laura A. Frey-Law
Addresses: Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa, USA ' Graduate Program in Physical Therapy and Rehabilitation Science, Carver College of Medicine, The University of Iowa, 1-246 Medical Education Building, Iowa City, Iowa, USA
Abstract: A thorough understanding of human physical capability is very important for human factors. Because muscle strength is a function of contraction velocity and joint position, i.e., a three-dimensional, torque-angle-velocity (TAV) relationship, peak torque at the wrist joint was obtained from healthy men and women at angular velocities varying from 0 to 240 deg/sec and across the stretch-free range of motion in the flexion-extension, radio-ulnar deviation, and supination-pronation directions. The corresponding TAV envelope models were developed using the best fit logistic functions to the experimental data. The findings of the study advance our understanding of normative wrist joint strength in multiple planes of motion and highlight the nonlinear relationships with joint position and velocity. These results may help to improve workplace design and risk assessment for musculoskeletal injuries, as well as enable modern digital human models to make more realistic predictions of hand and arm movement and wrist muscle exertion intensities.
Keywords: human factors; muscle strength; torque-angle-velocity relationship; performance capacity envelope; mathematical modelling; logistic function; 3D strength surfaces; three-dimensional strength; peak torque; wrist strength; wrist joints; wrist motion; joint position; velocity; workplace design; risk assessment; musculoskeletal injuries; digital human modelling.
International Journal of Human Factors Modelling and Simulation, 2015 Vol.5 No.1, pp.33 - 52
Received: 23 Dec 2013
Accepted: 03 Sep 2014
Published online: 12 Mar 2015 *