D.C. Rollergirls work up a sweat by bending over, walking their hands out to do a pushup and then reversing the exercise.

Even out of their skates, the ladies of roller derby are tough to keep up with. Fortunately, the D.C. Rollergirls Crash Course at BodySmith doesn’t involve any actual crashing.

What It Is: The conditioning moves that are part of the regular D.C. Rollergirl practice routine aren’t enough for ladies striving to up their game. So about a year ago, a derby diva asked trainer Courtney Shelton to develop a program for women affiliated with the local league, and he obliged with a routine that’s tailored to the demands of the speedy sport. Shelton’s not a skater himself, but he’s studied enough of what happens at the bouts at the D.C. Armory — “There’s a lot of hip action and pushing,” he says — to know what will help the Rollergirls come out on top. The focus is on leg strength, balance, flexibility — and, of course, power to give shoves more oomph.

Where It Is: Originally, the class was limited to Rollergirls, but when BodySmith recently made the leap from personal training studio to full-fledged gym, it invited its members, too. (See below for more on BodySmith.)

Moves: High knees for a minute. Lunges for a minute. Jump squats for a minute. Sense a pattern here? Shelton has students stick with each exercise for that long to boost endurance, which is critical for players. Same goes for referees, explains 30-year-old Amy Bodine, aka Screwy Decimal, who says the class has made it easier for her to be constantly on the go.

There are a few exercises that incorporate dumbbells, such as planks with rows and squats with overhead presses, but the majority of moves rely on students’ body weight. (That means prepare to do burpees.)

Shelton is big on curtsy lunges and other sideways steps to get the Rollergirls ready to head off in any direction. And because of his Pilates training, he keeps the core exercises coming: leg flutters, leg circles, bicycles, situps, plank variations.

Workout: “There’s got to be a reason I come here for torture,” says Camille Morin, 37, who competed as Camilla the Hun with the Rollergirls for six years and now is a team mascot specializing in trick skating. That reason? She knows that by giving Shelton her all, she’s protecting herself from muscle pulls and other potential injuries in the rink.

Shelton repeatedly cycles through six-minute sets of exercises before each short breather, which is why his students bestowed him with his very own roller derby name: Ihateyou. (“It’s all one word. I got that at the first class,” he says.) Although it’s an intense method of training, it’s also quick. After 45 minutes, everyone’s ready to stretch and roll on out of there.

Instructor Courtney Shelton urges Emily Gerston to keep her legs moving.

Crowd: Roller derby is competitive, and there’s a hint of that in class. “I don’t want to be the weak link,” says Emily Gerston, aka Oxford Commakaze. Derby is also kinda goofy, and that’s there too — especially when Shelton urges, “Come on, Screwy!”

The teammates are a close-knit group, but they don’t seem to mind other folks muscling in on their workouts. Guys have been dropping in a bunch, says Shelton, who notes that they usually can’t keep up with the ladies.

At a session last Tuesday night, 26-year-old Vera Chernova was sweating along with the Rollergirls. She’s been coming for a month — “Although after the first class, I skipped a week to recover,” she says. Regular attendance has made her feel stronger already. And watching the other women in class motivates her to push harder. Maybe one day she’ll even try out for the team, but for now, Chernova says, she’s content to work out with them.

D.C. Rollergirls Crash Course is 10 a.m. Sundays and 7 p.m. Tuesdays at BodySmith Gym + Studios (1630 14th St. NW, 202-772-0001, Bodysmithgym.com). Membership is $79 per month.

Body Parts

BodySmith is bulking up, says owner Stuart Smith, who has ambitious plans for the former personal training studio. The larger space he’s expanded into down the block from his previous location holds both a 5,000-square-foot private training area and a 7,000-square-foot membership gym. Murals will soon be going into the group exercise studio and the Spinning studio. Another anticipated addition: JuicyMax, a juice bar named for Smith’s son. Also in the works are a Pilates/massage studio next door and a huge rooftop deck. The outdoor space, expected to open next year, will feature a 4,500-square-foot turf surface for training.