five ficvors. gluten free. >>> because want your daughter to hang out with kids who go by nicknames as kid vicious some i got to hang out with parents who think it is one of the best things to happen to their little girl. >> it's all real hitting, it's real falls. none of it is staged. >> reporter: roller derby is not for sis cities. when you're skating going that fast and bumping into each other, it's a pretty rough sport. >> rough especially at the age of 7 and no older than 17. >> sometimes it's great being this small. i can get through cracks of things and i can duck. >> reporter: getting through hip checking girls is how they score points in a roller derby bout. this is video of the destroyer. >> i've gotten a lot tougher because i used to cry a lot. so, yeah. >> i've seen them take falls where i know before derby, i would have had to run out there, pick them up and carry them off. and now they're jumping back on their feet as quick as they can and getting back in the pack. >> reporter: maybe