I am a fitness instructor. Training only certain parts for a long time will lead to excessive development of these parts, which will not only lead to uncoordinated development of body shape, but also easily lead to sports injuries. For example, after a long training, the pectoral muscles will become too developed, and the shoulders will be pulled forward, making people prone to hunchback. But also reduce the range of motion of the shoulder joint, which is easy to cause chronic injury. It is suggested to combine other exercises to make the muscles of the whole body develop in an all-round way. If you have any fitness questions, you can ask our coach to answer them.