The objective of this study was to describe the in-seat movement and weight-shifting behavior of full-time wheelchair users. We measured everyday sitting behavior for 192 d across 28 individuals who used manual wheelchairs as their primary mobility device. To obtain the measurements, we used eight thin force sensors placed under participants' wheelchair cushions. On a typical day, participants spent an average of 10.6 +/- 3.0 h in their wheelchair and transferred out of the wheelchair 8.4 +/- 4.3 times. Participants only performed pressure reliefs (90% off-loading of the entire buttocks for at least 15 s) 0.4 +/- 0.5 times per hour they were seated in the chair, but they performed weight shifts (WSs) (30%-90% off-loading of at least one side of the buttocks for 15 s) with a frequency of 2.4 +/- 2.2 times per hour. Despite the higher frequency of WSs, they were not performed in a routine manner. Half of the days studied included one segment of upright sitting lasting at least 2 h without a WS. Given these observations, we conclude that seating evaluations should emphasize positioning individuals in a way that facilitates reaching, leaning, and transferring in a safe manner, not only to improve function but also to affect buttocks loading.
Keywords: Activity; behavior; buttocks; interface pressure; monitoring; pressure relief; pressure ulcer; sitting; spinal cord injury; weight shift; wheelchair.