[1] The purpose of a weight lifting belt is twofold: it reduces stress on the lower back muscles by allowing the lifter to safely increase intra-abdominal pressure, and it increases the lifter's proprioception which may lead to a decrease in lumbar hyperextension and other forms of spinal deformation.
The belt's shape was designed so as not to hinder weightlifters during performance of the snatch and clean and jerk.
Powerlifting belts are of a fixed width, and stiffer than traditional weight lifting belts, since powerlifters generally don't perform olympic style exercises such as the snatch and clean and jerk.
The belt is usually used in exercises where the lower back gets a heavy load, like the squat, deadlift,[3] or military press.
In industrial settings, back support belts have not been proven to reduce the frequency or severity of injury.