The main functions are as follows. The first point is that once you are exhausted in training, you need someone to help you lift the barbell. The second point is that if the trainer has an accident during training, the person behind the protector can help him share some strength, and the person next to him can have a certain reaction time and remove the barbell in time. The third point is to help squatters observe the standard degree and range of movements, which also plays a certain encouraging role.