Adaptation of Torso Movement Strategies in Persons With Spinal Cord Injury or Low Back Pain

Abstract

In Brief Study Design. Controlled laboratory study. Statistical regression and between-group comparisons. Objective. To characterize functional limitation and adaptive strategies in seated manual transport tasks for spinal cord injury (SCI), low back pain (LBP), and control participants. Summary of Background Data. People with SCI are known to have adapted electromyographic activities and slow hand movement velocity, while those with LBP have reduced range of motion and lumbar joint contribution. However, their resultant outcome in torso movements has not been systematically quantified. Methods. Seated participants performed either 2- or 1-handed loaded transports to 1 of 6 targets 49 cm above the hip-point, at 0°, 45°, and 90° azimuths, at close and far distance. Three-dimensional torso movements were modeled by combinations of B-spline base functions. Results. The SCI and LBP participants exhibit smaller torso flexion and axial rotation than control participants. The SCI participants tend to move the torso away from the target to maintain upper body balance. These differences among groups are significantly reduced in the 1-handed transport condition and/or transports to the frontal target. Conclusion. The movement patterns suggest that SCI participants may have adapted torso movement strategies to compensate for the limited control of upper body balance, while LBP participants may limit torso motion to avoid pain. Torso movement patterns affected by spinal cord injury or low back pain were statistically modeled and quantified on seated participants performing manual load transport tasks. The adaptation in movement strategies reflects their attempts to compensate for impaired balance control (spinal cord injury) and minimize movement-induced pain (low back pain).