Doesn't seem fair to rate a movie about roller derby. The whole subject is so damned interesting and energizing that even the least accomplished documentary will hold my attention. Sort of like pornography, I suppose, but not in a creepy way, I hope. While not discounting the role of heterosexuality, I suggest that roller derby enthralls the straight man not so much via the outfits but via the prevalence of confident, powerful, happy women having a blast and loving themselves and their energy. This documentary lacks a little focus, perhaps. Neither this nor WHIP IT is stellar art, but the roller derby and the girls of roller derby survive both, I'd say, and make both better movies than they have a right to be.