Justin Gatlin, U.S.A. Track and Field
Justin Gatlin is a world renowned sprinter, and this year he will compete in the 100m sprint and the 4x100m relay, representing the United States at the Olympics for a second time. Justin has a lot to live up to after winning three medals in the 2004 Olympic Games in Athens. Sprinting requires full body strength and uses different types of muscle fibers than other forms of running.
There are two different muscle fiber types, slow twitch and fast twitch. “To sprint, athletes need to use fast twitch fibers. They are the same muscles as others, but these fibers tend to be bigger and a lot more explosive to give the quick start and speed for short distances,” explains Dr. Howard Goodman, an orthopedic surgeon at Maimonides. “Furthermore, a sprinter’s muscles need to be looser (more elastic) than regular runners muscles in order to avoid injury in the very quick motions.” This is not to say that sprinters like Justin Gatlin use different muscles than other runners. Instead, they change the composition of their muscles through training.
“Fast twitch muscles are good for the quick movements required by sprinters,” states Dr. Goodman. “They can generate short bursts of strength and speed because fast twitch fibers are anaerobic.” This means that fast twitch fibers don’t need oxygen to make energy. Instead, fast twitch muscle fibers use high energy phosphates for energy. “These high energy phosphates, known as adenosine triphosphate (ATP) and creatine phosphate (CP), are stored in small amounts within muscle cells,” notes Dr. Goodman. After this energy is used up, a process called anaerobic glycolysis occurs and uses glucose (blood sugar) as muscle fuel. “While the fast twitch fibers are extremely efficient for more forceful motion and faster contractions, they are quicker to fatigue,” notes Dr. Goodman. This occurs because lactic acid, a byproduct of anaerobic glycolysis, builds up within the muscles as athletes exert themselves. This is the ‘burn’ felt in muscles after strenuous exercise. “Too much lactic acid can damage muscles and cause cell death,” explains Dr. Goodman. Fortunately for Justin Gatlin, his intense training can increase the amount of time or the amount of contractions that his muscle can handle before going into overload.