Sports have a great deal of affinity with art. Sports such as ice skating, ice hockey or tai chi are in themselves very much like artistic spectacles. Traditional activities such as gymnastics and yoga, or more recently, bodybuilding, also combine elements of sport with artistic elements.
The fact that art is so close to sport in some situations is probably related to the nature of sport. The definition of sport establishes the idea of engaging in an activity not only for a routine purpose; for example, not just running to get someplace, but running by choice, for the purpose of maintaining physical fitness.
This is similar to a common vision of aesthetics, which views objects for more than their utility. Similarly, a sport like diving is not valued only as an effective way to avoid obstacles; ability, skill and style also matter.