A spinal motion sensor comprised of a system and method which detects any bending or twisting motion in the users back. According to the method of the invention, the system alerts the user that the motion may result in a harmful injury. The device is worn on the belt of the user and features one or more inertial sensors, which detect the position of the users back. Additional attitude sensors may be configured to be worn on the users upper back or shirt collar, to determine the position of the back at additional locations. According to the method of the invention, the device presents an audible warning when the user moves into an inappropriate position.
