To prevent low back pain during prolonged sitting, an inflatable lumbar support cushion has been developed that provides lumbar continuous passive motion (CPM). We have developed a dual CPM device, in which an additional CPM cushion is located in the front portion of the seat. The dual CPM device has two synchronized bladders with reciprocal motion in the opposite phase: When one bladder inflates the other deflates. A total of 23 male volunteers without low back pain sat in a chair for a two-hour period under several test modalities and indicated lumbar discomfort on a 10-cm visual analog scale (VAS). The VAS scores were 8.2±1.6 without lumbar support, 5.9±1.9 with the static support, 5.7±2.3 with lumbar support CPM, and 4.3 ±2.4 with dual CPM. Compared to the lumbar support CPM, significant (p<0.05) improvement in VAS scores was obtained with the dual CPM device.
