12-year-old girl knee calf pain can generally take a comprehensive therapeutic intervention, but first to the hospital for a detailed examination, and then according to the specific cause of the symptomatic cure, caused by knee calf pain is generally due to sports injuries or growing pains and so on. 1. Sports strain: It is considered that it may be due to the intensity of sports, more than the body’s ability to withstand, resulting in damage to its parts, and may also be swollen and painful. It is recommended that the child rests and avoids further strenuous exercise. 2. Growing pains: 12-year-old girls are growing and developing rapidly, the growth rate of bone is fast and greater than the growth rate of the surrounding joint capsule and ligaments, which may lead to a mismatch between the growth rate of soft tissues and bone tissues, and growing pains in the knee joints, which can be relaxed by massaging or by following the doctor’s instructions to supplement with calcium supplements. Usually pay more attention, try to avoid excessive exercise, timely supplementation for children, such as nutrition and calcium, diet should be reasonable and healthy and nutritious, to develop a good dietary habits.