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Volume 46 Number 9, 2009
   Pages 1099 — 1108

Abstract — Does upper-limb muscular demand differ between preferred and nonpreferred sitting pivot transfer directions in individuals with a spinal cord injury?

Dany Gagnon, PT, PhD;1-4 Alicia M. Koontz, PhD, RET;1,3* Eric Brindle;1,3 Michael L. Boninger, MD;1-3
Rory A. Cooper, PhD1-3

1Human Engineering Research Laboratories, Department of Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA; 2Departments of Physical Medicine and Rehabilitation, 3Rehabilitation Science and Technology, and Bioengineering, University of Pittsburgh, Pittsburgh, PA; 4School of Rehabilitation, University of Montreal, Montreal, Canada

Abstract — This study's main objective was to determine if upper-limb (UL) muscular demand was reduced when individuals with a spinal cord injury (SCI) performed a sitting pivot transfer (SPT) in the preferred direction compared with that in a nonpreferred direction. Fourteen individuals (mean +/- standard deviation age 47.0 +/- 8.3 yr, height 1.80 +/- 0.08 m, and weight 75.3 +/- 11.3 kg) with SCI levels ranging from the sixth cervical to first sacral vertebra levels volunteered to participate in this study during the 2008 National Disabled Veterans Winter Sports Clinic. Surface electromyography (EMG) was used to record activity of the biceps, triceps, deltoid, pectoralis major, trapezius, and latissimus dorsi bilaterally during SPTs. These transfers were performed in each of the preferred and nonpreferred directions from the individuals' wheelchairs to a padded tub bench of even height. To quantify electromyographic muscular utilization ratio (MUREMG), we normalized EMG data recorded during the transfer tasks to values obtained during static maximum voluntary contraction and then multiplied this ratio by 100 to obtain a percentage MUREMG (%MUREMG). The overall peak %MUREMG and the area under the %MUREMG curve were selected as primary outcome measures. Similar peak %MUREMGs were found between the preferred and nonpreferred transfer directions for all muscles from which data were recorded (p = 0.053 to 0.961). The peak %MUREMGs were also found to be similar between the leading and trailing ULs during the transfers in all muscles from which data were recorded (p = 0.125 to 0.838), except for the anterior deltoid, which was found to be solicited the most in the trailing UL (p = 0.008). Comparable areas under the %MUREMG curves were calculated between the preferred and nonpreferred transfer directions for all muscles (p = 0.289 to 0.678) and between the leading and trailing ULs (p = 0.104 to 0.946). These results indicate that direction preference expressed by individuals with SCI when transferring between seats of even height is not explained by relative muscular demand differences.

Key words: activities of daily living, elbow, electromyography, paraplegia, rehabilitation, shoulder, spinal cord injury, task analysis, task performance, tetraplegia, upper limb.


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