Manual movement coordination adapted to spinal cord injury and low back pain

Spinal cord injury (SCI) and low back pain (LBP) significantly limit personal and occupational activities. Since upper body movements are crucial to extend hand reach envelopes and maintain postural balance, coordinated control of torso and hand movements is essential. In this study, adapted patterns of coordination were investigated in SCI, LBP and control participants performing seated manual material handling tasks, in which a load was transferred with both hands from a home location to one of 4 targets in the mid-sagittal plane.Torso peak velocities are larger and delayed for the SCI when compared to the control group, while hand peak velocities are comparable. However, hand peak velocities are smaller in the LBP than control group. Hand movements generally precede torso movements for all groups, but more prominently for the SCI than the other groups. Furthermore, for SCIs torso movements were suppressed until the hands were aligned with target elevation.These results indicate that SCI individuals have developed a unique coordination pattern to compensate for their limited balance control, although this strategy may reduce their effective workspace and overload the upper extremities. In contrast, LBPs seem to have reduced movement speed while their coordination patterns are generally similar to those in the control group.Relevance to industryThis study analyzed movements of persons with spinal cord injury or low back pain in manual material handling tasks. Assessing their adapted movement strategies would help to improve workspace design to accommodate workers with limited capacities and to provide quantifiable evidence and guidelines on the effectiveness of occupational rehabilitation programs.

► Spinal cord injury (SCI) and low back pain (LBP) significantly limit occupational activities.
► Hand–torso movement patterns were assessed for manual material handling tasks in SCI, LBP and non-disabled persons.
► It was observed that SCIs have developed a unique coordination pattern to compensate for their limited balance control.
► LBPs seem to have reduced hand movement speed while their coordination patterns are generally intact.