but this one, i believe, is best described as painful. no, let's go with humbling because these women make it look so darn easy. >> there it is! >> unbelievable! >> but i'm not one to say no to a challenge, to find out why the decidedly female sport of roller derby is still with us, i came to meet the san diego derby dolls and their general manager, a woman that calls herself isabelle ringer. roller derby in an undisclosed location. he'll loy smokes. what a great place to break your ringer. mike rowe. >> welcome to the dollhouse. >> i am the general manager of the south dakota derby dolls. >> call me mike. what is this?