In sprint races, where every fraction of a second is significant, sprinters must have the proper stride length and frequency, and body position. A 100-meter track sprinter will barrel down the track at top speed for about 10 seconds, and the muscles need a quick source of their cellular energy, known as ATP. The majority of this energy comes from anaerobic processes, since they are quicker than aerobic energy production. Therefore, a high aerobic capacity, defined as the ability to produce energy using oxygen, likely does not benefit a sprinter in terms of race performance, although it might help recovery from hard workouts and running multiple rounds in a championship meet.
Adenosine triphosphate, commonly known as ATP, provides the muscle cells with energy so they can contract. When the muscles move, they must continue to replenish ATP to keep moving. The muscle has three ways of producing this energy: the phosphagen system is the quickest-acting, the oxygen-requiring oxidative system is the slowest, and the glycolytic system is between the two. During a maximum-intensity sprint, the phosphagen and glycolytic systems are the primary ATP suppliers, with the oxidative system playing a minimal role. Since oxidative energy production does not make a significant contribution to exercise lasting less than two minutes, improving aerobic capacity probably will not improve sprint performance.
Skeletal Muscle Characteristics of Sprinters
Human skeletal muscles contain two types of fibers: type I fibers develop force slowly and have a high aerobic capacity, whereas type II fibers develop force quickly and have a lower aerobic capacity. Sprinters tend to have a lower proportion of type I fibers than non-athletes or endurance athletes. Additionally, the type II fibers that elite sprinters have are more capable of producing energy through anaerobic systems, whereas their oxidative capacity is only slightly above average. Therefore, even if an elite sprinter's aerobic capacity is enhanced, it is likely not the major contributor to their top-level sprint performances.
Sprinting With Reduced Oxygen
Race times for events less than two minutes usually are unaffected by reduced oxygen supply characteristic of high altitude, since the primary source of energy is through anaerobic means. One 1999 study published in the "Journal of Applied Physiology" demonstrated this by testing sprint speed and aerobic capacity through a variety of treadmill tests in a normal oxygen environment and a low-oxygen environment. Aerobic capacity was lower in the low-oxygen environment, but maximum sprint speed was the same in both environments. Therefore, reduced aerobic capacity likely does not impair sprint speed.
Aerobic Capacity and Recovery
Although aerobic capacity might not directly improve sprint speed, it might help athletes recover from difficult workouts. Additionally, most track meets require sprinters to run multiple races and relays per day, and good aerobic capacity will help maintain performance capacity throughout the day. In terms of sprint training, training to improve aerobic capacity is best in the preseason to build a foundation for the higher-speed training and racing later in the peak season. This training should consist of several intervals longer than the race distance; for example, 10 runs of 200 meters for a 100-meter sprinter at about 75 percent of maximal sprint speed, with less than one minute recovery.