Middle distance races are not the subject of a hard and fast definition. Until approximately 30 years ago, the middle distances were thought to be all track races of between 400 m and the mile. Today, most observers regard a middle distance runner as one who competes in the races that range between 800 m and 5,000 m.
The middle distance runner is an athletic hybrid. These runners must possess excellent aerobic capacity, coupled with the power to drive forward for a finishing kick that may be as long as 300 m to 400 m, the point where almost all middle distance races are decided. The middle distances also require the greatest degree of tactical sense and intelligence in the runner, as the decisions that must be made concerning concepts such as front running, pack position, or the timing of an accelerating burst will all be determinative. The absolutely fastest or strongest runner does not always win a middle distance race.
While the men's 100-m Olympic championship is the most glamorous running event in the world, and the Boston Marathon is likely the best-known race, the one-mile race has a fabled history. The pursuit of the four-minute barrier in the mile by Roger Bannister of England, challenged by John Landy of Australia and Wes Santee of the United States, captured international sporting attention through the early 1950s, as did the later battles of Sebastian Coe and Steve Ovett in the late 1970s. American world record holder Jim Ryun and John Walker of New Zealand were two of the most famous international athletes when at the peak of their respective careers. It is a measure of the regard for the one-mile race distance that when the International Amateur Athletic Federation (IAAF) determined in 1976 that all of its records would be maintained in metric measure only, the mile was exempted.
The middle distances place physiological emphasis on a number of factors. The distribution between fast-twitch and slow-twitch muscle fibers in an elite middle distance runner is usually close to a 50% pattern, in keeping with the hybrid qualities of these athletes. To utilize this balance, most middle distance training programs combine aerobic and anaerobic training, with the anaerobic aspect often-intense speed training. In the 1980s, the successful middle distance runners of Africa, often athletes from the Rift Valley region, with an altitude of approximately 7,000 ft (2,200 m), pioneered a middle distance training program. In the program, the runners would warm up by running at a relaxed pace (7 minutes per mile) for approximately 4 mi (6.4 km). They would then run 40 400-m circuits of the track; each 400 m would be run in less than 60 seconds, with no more than one minute rest permitted between the 400 m intervals. Then the athletes would conclude the workout with another 4-mi run similar to that that began the session.
The focus of the African workout, which is extreme for any runner except those who are highly trained, is the mutual development of anaerobic strength (through the short recovery period), with the aerobic training that is supported by the significant volume of running (10 mi/16 km of high intensity track running, with 8 mi/12.8 km of easier unstructured running).
Sprint racing has no particular tactics to be employed; the runners go all out for as long as they can maintain speed. Marathon runners (as well as triathlon and Ironman participants) must employ tactics, but the nature of the event permits such race planning to be made over a relatively long period of time; instantaneous decisions are rare in such races.
Middle distance races are often decided by tactical decisions. In the 800-m race, the runners begin in lanes and they are allowed to get to the inside of the track oval, and thus run the shortest distance possible, after 100 m. The 1 mi/1,500 m begins with all runners behind a gently arcing start line. The runner must make a number of important decisions, each based primarily on the runner's physical attributes. A front running middle distance competitor is one who often tries to wear down the rest of the field with a strong early pace. Racers who possess a well-developed finishing kick will often wait in the pack of runners and attempt to push to the lead over the last 200 m to 300 m. Many athletes will feint a move out of the pack to test the resolve of the other racers. As with any sport that engages a high level of tactical consideration, the successful middle distance runner must spend considerable time developing a resilience and hypercompetitive attitude.
In middle distance races, each lap time is called out to the runners to orient their pace. In some middle distance events, particularly the mile (or the 1,500 m), race promoters may sometimes employ the services of a runner known as a "rabbit," often an accomplished 800-m runner who can take the runners into the second half of the mile at the highest possible pace. Rabbits have a long history in elite races.