Is Roller Derby A Skating Sport?

roller derby is a kind of roller skate game, played by two teams of 15 people.

The game consists of a series of short-distance matches (jams) in which both sides designate a jammer (wearing a star on a helmet) and four blockers to slide a circle counterclockwise. The batsman circles the opposing team to score. Both teams try to hinder their opponent's jammer while helping their jammer-in effect, attacking and defending at the same time.