For muscle training, the so-called "practice for one day and rest for two days" means that if you give enough exercise stimulation to a certain part that day, the muscles in this part need to be separated for more than 48 hours before they can exercise again. Muscles grow at rest, so continuing to exercise the next day will affect the appearance of muscles. For example, you can't practice your chest muscles the next day, but you can practice your legs, back, abdominal muscles and so on. So you can still exercise your muscles every day. In addition, weightlifters pursue muscle strength rather than muscle shape.