In isometric exercise, muscles are moved through a short distance against a high resistance, as in weight training. Isometric exercise is best for developing large muscles, while isotonic exercise conditions the cardiovascular system by increasing the amount of blood that the heart can pump and causing proliferation of small blood vessels that carry oxygen to the muscles. These changes make possible longer sustained activity. Arthroscopic surgery is usually performed on an outpatient basis, frequently under local anesthesia, and significantly reduces rehabilitation time. Long-distance runners also suffer knee injuries, but a more common problem for them is a stress fracture, a weakening of the front of the shinbone resulting from overuse, accompanied by pain and possible bone cracking.
Ligament tears are common in gymnastics.
Many of these injuries heal with rest followed by proper rehabilitation. Sports injuries involving loss of consciousness, loss of blood, fractures, or severe impact to or twisting of the neck or back require immediate emergency medical treatment. Many other sports injuries, however, such as sprains, can be treated initially with rest, icing, compression, and elevation. Prevention of sports injuries depends primarily on good conditioning. Athletes are also protected by the use of better padding materials, facemasks in football and ice hockey, and eye protectors in squash and other racquet sports.