"You really practice six days a week at this level of the game, and that doesn't even count all the other workouts you're doing. I do 200 crunches and 80 push-ups a day in the morning before I go to work, I run, I go to yoga, we're going to the gym and lifting weights," she said.
The intense commitment has paid off in legions of fans, including the Derby Widowers, husbands and boyfriends who thrill to and/or wince at every collision.
"It's definitely a concern, because I'm getting married in September, and my future wife is out there," said one Widower. "I'm like, Boy, I hope she doesn't have to go on crutches or something."
Roller Derby is so popular, it even has a junior league -- not to be confused with the Junior League -- called the Derby Bratz, with girls as young as eight years old. Members include Hannah Mon-Slammah and Prima Basherina.
Derby enthusiasts hope this next generation will make sure the sport doesn't disappear again.
"If your daughter wants to play roller derby," Fackler said, "you should be like, 'Yes, that is strong women, working hard. Awesome.'"