Gym belts, or weight lifting belts, are used by all sportsmen who train using free weights. There are few professional weightlifters, if any, that don't use a weight lifting belt when they are training and competing. It is more to a weight lifting belt than just buying it and putting it on when you workout.

A weight lifting belt is used as a protective measure for the body as you lift extremely heavy weights. It is designed to protect your back from hyper extending by pushing in your core muscles and allowing them to work for efficiently throughout a movement.

The belt itself will sit on the lower back and the upper part will sometimes rest on the upper thighs during squat like movements. When the weight lifting belt is sitting on the thighs, the lifter is reminded to keep their back straighter in order to avoid this.