The effect of body position on bioelectrical resistance in individuals with spinal cord injury.

Abstract

The purpose of this study was to determine the effect of four different body positions on the resistance of the human body as assessed by Biodynamics Model 310 Body Composition Analyzer in a healthy population (Group A, n = 69) and long-term spinal cord injured (Group B, n = 13). Group A were tested in four body positions: supine, half-lying, standing and sitting in a wheelchair, while Group B were tested in supine and sitting positions. Testing order was randomized. A one-way repeated measures analysis of variance and a paired t-test demonstrated significant differences between position (p < 0.0001, Group A; p < 0.01, Group B respectively). In both groups, the greatest reduction in resistance was demonstrated for the sitting position. These differences were similar for both groups, as demonstrated by covariant analysis. Regression analysis demonstrated that supine resistance can be accurately predicted (R2 = 0.98) from assessments in a wheelchair. Such data transformations may be indicated where supine positioning is problematic or when wheelchair assessment procedures are more appropriate.