American football positions American football positions In American football each team has 11 players on the field at one time. The specific role that a player takes on the field is called his position. Under the modern rules of American football, teams are allowed unlimited substitutions; that is, teams may change any number of players after any play. This has resulted in the development of three "platoons" of players: the offense (the team with the ball, which is trying to score), the defense (the team trying to prevent the other team from scoring, and to take the ball from them), and the special
Health issues in American football to field condition. Because American football is a full-contact sport, head injuries are relatively common. According to the San Francisco Spine Institute at Seton Medical Center in Daly City, California, up to 1.5 million young men participate in football annually, and there are an estimated 1.2 million football-related injuries per year. An estimated 51% of injuries occur during training sessions, while 49% occur elsewhere. Injuries are nearly 5 times more likely to happen during contact training sessions than in controlled, non-contact sessions. Older players are at the most risk for injuries, while teams with experienced coaches and more assistant coaches