室内美式足球（Arena Football）是由前合众国美式足球联盟（United States Football League）和国家美式足球联盟（National Football League）主管吉姆·佛斯特所发明的运动。当他在1981年于麦迪逊花园广场（Madison Square Garden）观赏一场室内足球（Indoor Soccer）比赛时，他发明了这项运动的几项基本规则。在之后的五年内，他持续修正这些规则，并且举办一些测试比赛，直到他准备好于1987年成立室内美式足球联盟(Arena Football League，AFL)。联盟于2000年产生了一个称作af2的小联盟。其它人开始成立他们自己的室内美式足球联盟。这些联盟技术上来说因为佛斯特在1990年获得的规则专利因素（特别是在rebound nets ） ，并不是在打室内美式足球（实际上由Gridiron Enterprises所拥有）。

Arena football is a variety of indoor gridiron football played by the Arena Football League (AFL). It used to be a proprietary game (the rights to which were owned by Gridiron Enterprises) but the patent expired in 2007. The game is played indoors on a smaller field than American or Canadian outdoor football, resulting in a faster and higher-scoring game. The sport was invented in 1981, and patented in 1987, by James F. Foster, Jr., a former executive of the National Football League and the United States Football League. Though not the only variant of indoor American football, it is the most widely known, and the one on which most other forms of modern indoor football are at least partially based.