Wheelbarrow always requires teamwork, but extra communication is needed when the person in front is blindfolded. “I pulled on her ankles to get her to stop,” Eliza Moody, in purple, said at the debut class. The standing partners, who had their legs bound by a resistance band, also gave directions so they’d continue in straight lines.

To spice things up for February, Washington Sports Clubs in North Bethesda has introduced Tough Love boot camp, a workout designed to be by the book. And in this case, that book is the risque novel “Fifty Shades of Grey.”

“We have bars, bands and blindfolds,” instructor Libby Linden Rubin announced at the debut class Thursday, in a joking reference to the best-seller’s bedroom antics.

There’s nothing all that sexy, however, about the props in this context. Those bars are weights that need to be lifted, and the resistance bands boost the difficulty level of various exercises. As for the sleep masks, they’re a way to turn every move into a balance challenge.

“You’ll notice your muscles engaging and be more in tune with your body,” Rubin said, warning that the sightless sensation might not be right for everybody. “If you don’t like that feeling, it’s an option, of course, to take it off.”

Back-to-back squats forced partners to use each other as support. But only one at a time could check form in the mirror.

During “chapter one” of the class, students pair off for partner exercises, starting with the wheelbarrow. Everyone remembers the childhood classic: One person walks upright while carrying the legs of a partner, who’s moving on just his or her hands. Tough Love students graduate to a harder version that adds a resistance band around the ankles of the walker and a mask on the partner.

Not only is it more physically demanding that way, but it also requires more communication. The person in front doesn’t know where to stop to prevent smacking into a wall.

For the next round of exercises, which are performed solo, students have no one to trust but themselves. Rubin has students do one set normally before the masks come on to emphasize just how odd it is to step, jump and reach without visual cues. Students who have perfect form without the masks instantly become wobbly and tentative while wearing them during jumping jacks and lunges.

Single-leg deadlifts are a balance challenge; without eyesight, everyone wobbled and fought to keep from falling over.

Eliza Moody, 35, said she sensed every muscle in her ankles and core struggling to keep her upright.

The muscles Cheryl McAfee felt: the ones in her face responsible for smiling. The 51-year-old laughed as she made her way through the routine: “You can’t judge where you are. Lunging back, I couldn’t get my balance. I felt like I was drunk.”

After the masks came off Thursday, everyone had to sober up quickly — still ahead were V-sits, rows, crunches and pushups. By the end, students were 50 shades of red.

WSC North Bethesda, 10400 Old Georgetown Road; Thursdays through Feb. 28, 9:15 a.m., free for everyone; Mysportsclubs.com.