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Research Article  |   May 2006
Shoulder Muscle Activity Increases With Wrist Splint Use During a Simulated Upper-Extremity Work Task
Author Affiliations
  • Amy G. Mell is Research Assistant, Orthopaedic Research Laboratories and MedSport, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
  • Mark A. Friedman, MD, is House Officer, Orthopaedic Research Laboratories and MedSport, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
  • Richard E. Hughes, PhD, is Associate Professor, Orthopaedic Research Laboratories and MedSport, Department of Orthopaedic Surgery, University of Michigan, 24 Frank Lloyd Wright Drive, Ann Arbor, Michigan 48106; rehughes@umich.edu
  • James E. Carpenter, MD, is Associate Professor, Orthopaedic Research Laboratories and MedSport, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
Article Information
Splinting / Issues in Physical Rehabilitation
Research Article   |   May 2006
Shoulder Muscle Activity Increases With Wrist Splint Use During a Simulated Upper-Extremity Work Task
American Journal of Occupational Therapy, May/June 2006, Vol. 60, 320-326. doi:10.5014/ajot.60.3.320
American Journal of Occupational Therapy, May/June 2006, Vol. 60, 320-326. doi:10.5014/ajot.60.3.320
Abstract

OBJECTIVE. The purpose of this study was to test the hypothesis that wearing a wrist splint while performing a common light manufacturing task (moving an object from a bin) increases shoulder muscle activity.

METHODS. Electromyography (EMG) signals were evaluated from the anterior, middle, and posterior deltoid, trapezius, supraspinatus, and infraspinatus of 14 volunteers while they moved an object from a bin. Two test conditions were measured: with and without a wrist splint. The height of the bin was also varied.

RESULTS. Wearing a wrist splint increased maximum EMG for all six muscles and average levels for the deltoid (anterior, middle, posterior) and trapezius. As bin height increased, maximum muscle activity increased in the deltoid (anterior, middle, and posterior) and trapezius, and the average increased in the deltoid (middle and posterior) and trapezius.

CONCLUSIONS. Workplace factors can modify the activation of a patient’s shoulder muscles when he or she is wearing a wrist splint. An ergonomic job analysis should be conducted for patients who are returning to work wearing wrist splints.