Nearly 70% of the US population will experience back pain at some point in their lives. The annual cost to the US economy of back-related problems has been estimated to be in the billions of dollars. Sedentary jobs have been linked to an increased risk of back injury, and it has been shown that sitting for prolonged periods with a flattened lumbar curvature increases the stress on the intervertebral disks. Stress on the back can be reduced if the lumbar spine remains sufficiently curved. We are developing a device that will be worn on the lumbar spine, will monitor lumbar curvature, and will provide audio or vibrational feedback to the wearer when poor posture is assumed so that this posture can be modified to reduce the stress on the back. In Phase-I we will evaluate different methods for measuring lumbar curvature, develop a prototype device, and confirm the effect of feedback on posture modification. In Phase-II, we will investigate the long-term effects of posture modification on back pain and back injury