American football positions four linebackers, and four defensive backs (two cornerbacks, a strong safety, and a free safety) Special teams are units that are on the field during kicking plays. While many players who appear on offensive or defensive squads also play similar roles on special teams (offensive linemen to block, or defensive players to tackle) there are some specialist roles which are unique to the kicking game. 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
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