Compared with boys, the strength of tendons and ligaments around the bones of girls is far less than that of men, so don't exert too much force at the beginning of fitness or it will easily cause injuries to tendons and ligaments. Knee, yes. Because of the difference of pelvic structure, the Q angle of girls is much larger than that of boys. It is easy to wear the medial ligament of the knee when squatting. It is best to fully master the action mode before squatting with weight. Also, during menstruation, don't exercise if it hurts. If it doesn't hurt, you can actually exercise. Control the intensity and don't do exercises with excessive abdominal pressure. During this period, the secretion of growth hormone is relatively strong, so even if the intensity is not great, the effect can be achieved.