Daily classes are necessary not only to mold the body and develop the necessary physical skills but also to maintain the body in its proper condition and prevent injury. Many dance movements make strenuous and unnatural demands on the joints, muscles, and tendons, and it is easy to strain or damage them if the body is not properly maintained. Some bodies are more suitable for training than others, and in the West many aspiring dancers undergo extensive medical scrutiny to ensure that they have no weaknesses or disabilities."