Any precise definition of sport can be highly contentious. In practical terms, sport is defined by its strict association with athletic competition and its public interpretation by the public. While sport may have been founded on various factors, one of the most important is the idea that competitive athletics is a natural occurrence, which may be regulated or banned depending upon its strict association with particular sport.
In many ways, sport is the equivalent of the universal recreational activity. As such, it is governed by many of the same rules that govern common leisure activities. Aspects such as rules on body contact, intentional grounding or collisions, rules governing sporting events, etcetera are all related to sport. Because of the degree of public interest in specific sporting events and the general level of agreement with the concept of sport, many sporting bodies have been created to ensure fair competition and facilitate participation by both competitors and spectators. Although the exact nature and content of sport vary across different regions and communities, common aspects of sport include physical activity, competitive rivalry, skill, and even an element of sportmanship.
Common examples of sport include ice hockey, American football, Australian rules football, tennis, and motor vehicle racing. The association football sport is the most popular of all sports; however, the physical contact of the game can cause many serious injuries and even fatalities. Another example is American football, which unlike other sports enjoys widespread popularity in the United States. To protect the interests of the participants in such sport, various governing bodies have been formed, including the NFL, NBA, and MLB.