The Role of Center of Mass Kinematics in Predicting Peak Utilized Coefficient of Friction During Walking*


  • Judith M. Burnfield Ph.D., P.T.,

    1. Movement Sciences Center, Institute for Rehabilitation Science and Engineering, Madonna Rehabilitation Hospital, 5401 South Street, Lincoln, NE 68506.
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  • Christopher M. Powers Ph.D., P.T.

    1. Musculoskeletal Biomechanics Research Lab, Department of Biokinesiology & Physical Therapy and Department of Radiology & Orthopaedic Surgery, University of Southern California, 1540 E. Alcazar St. CHP-155, Los Angeles, CA 90089-9006.
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  • *

    This work was presented, in part, in poster format at the International Society of Biomechanics XIXth Congress in 2003. The research was performed in the Musculoskeletal Biomechanics Research Laboratory, Department of Biokinesiology and Physical Therapy, University of Southern California, 1540 E. Alcazar St., CHP-155, Los Angeles, CA 90033.

Additional information and reprint requests:
Judith M. Burnfield, Ph.D., P.T.
Director, Movement Sciences Center
Institute for Rehabilitation Science and Engineering
Madonna Rehabilitation Hospital
5401 South Street
Lincoln, NE 68506


Abstract:  Slips frequently occur when the friction required between the foot and floor exceeds available surface slip resistance. To date, the ability to identify variables that predict an individual’s friction needs during walking, or utilized coefficient of friction (COFU), remains limited. Understanding COFU in the context of pedestrian/walkway accidents is important as individuals who demonstrate higher COFU are at a greater risk of slipping. This study determined if whole body center of mass (CM) kinematics were predictive of peak COFU during walking. Ground reaction forces and kinematic data were recorded simultaneously as subjects walked. Stepwise regression analysis determined that the combination of the subject’s CM-to-center-of-pressure angle and CM anterior (i.e., forward) velocity predicted 62% of the variance in peak COFU during weight acceptance (< 0.001). The identified relationships between CM kinematics and peak COFU provide insight into how gait and individual anthropometric characteristics may increase risk for slip initiation.