Roller derby- underrated

Roller derby is a contact sport played by two teams of five members roller skating in the same direction around a track. Game play consists of a series of short matchups ("jams") in which both teams designate a scoring player (the "jammer") who scores points by lapping members of the opposing team. The teams attempt to assist their own jammer whilst hindering the opposing jammer — in effect, playing both offense and defense simultaneously. Roller derby is played by more than 1,200 amateur leagues worldwide.[1]