Abstract: A fabric belt includes a pair of segments formed of a non-elastic material coupled to an elastic material segment. The belt includes fabric attachment pads at its end portions to allow it to be secured to a wearer's torso. A sensor is secured across the elastic segment of the belt by a separate tension adjustment segment which is secured to one of the non-elastic segments by a second fabric attachment pad coupling. The sensor includes a motor and battery operatively coupled through a tension responsive switch. The motor rotates an off-center weight to produce a vibratory action when energized. As the user wears the belt, each time the user neglects to maintain proper muscle tightening the vibratory alert is produced by the sensor.