A 90-minute workshop includes a tour of the exhibition and a yoga workout led by Kathy Duke, left. (Astrid Riecken/for The Washington Post)

The number of people wearing stretchy pants while browsing the Sackler Gallery exhibit “Yoga: The Art of Transformation” is almost as impressive as the collection of 133 objects on display. A few folks have even walked in with mats slung over their shoulders, panicking museum staffers who don’t want to have to serve as the pose police.

There’s no question that the sculptures, scrolls and paintings are meant to inspire. “This will awaken a desire to practice,” promises John Schumacher, one of Washington’s foremost yoga instructors and a consultant for the exhibit, the world’s first show devoted to yogic art. But spontaneous yoga isn’t allowed in the Smithsonian Institution.

So visitors who aren’t content to sit on a bench and breathe are instead invited to take part in a new kind of program. “Art in Context: Practicing Yoga in the Galleries” puts a group in the hands of both a museum docent and a yoga instructor, and ends in an open space in the final room in the exhibit. That’s where participants — and only participants — can experience a short yoga class.

“It’ll always be based on that particular teacher’s understanding of what people have seen,” explains Schumacher, who recruited instructors from studios across the region to pitch in for the program, which runs three times a week (Wednesdays at 12:30 p.m. and Sundays at 10:30 a.m. and 3:30 p.m.) until the exhibit closes in January.

It’s just as much a learning process for the tour guides as it is for anyone who signs up to come along. Neither docent Delrie Hobbs nor instructor Kathy Duke knew exactly what would happen when they gathered the very first program participants this month. But they had a game plan based around a few pieces they had selected together, and no problem determining who was in the group: the stretchiest pants, T-shirts from various yoga studios and slip-on shoes were dead giveaways.

“This room has to do with teachers,” Hobbs announced upon entering the first gallery, and then launched into a brief history of a Buddha fragment and a white marble figure called a jina. What you’ll notice, she added, is that both figures are in the lotus posture. That’s because meditating cross-legged for long periods was considered the only way to get rid of karma, which was “a sticky material substance that coated the clear light inside of us,” she said.

Turning her attention to the final object in the room, Hobbs pointed out that this one was not like the others.

As one woman on the tour opined, “She’s not looking serene.”

“No,” Hobbs agreed. “She’s fierce, creating a whistle, a type of war cry.” And Hobbs led them to three other similar figures — called “yoginis” — in the adjoining room. “This one has fangs and crazy eyebrows, and she has snakes on her arms,” she said.

That’s when Duke swooped in to discuss the role of women in yoga. Although many early images exclusively feature men, statues like these serve as a reminder that there was a role for powerful women, too, she said.

The next stop was a green statue of the Hindu god Vishnu that’s notable to yogis for several reasons. One, the figure has a yoga strap wrapped around his legs, which is unexpected in a piece circa 1250. Two, he’s depicted with a lion’s face — a perfect segue, Duke noted, to a lion pose they’d be doing in class soon.

That same room also holds a series of pages from “Ocean of Life,” a 16th-century Persian text. It’s one of the first yogic sources showing postures other than simple seated positions. “My favorite is this one description. It reminds me of the game Twister,” Hobbs said, and then started reading: “The left foot on the right foot, holding the buttocks on both feet, holding the head evenly between the two knees, placing both elbows under the ribs, putting the hands over the ears, and bringing the navel toward the spine.”

Several participants, including Stair Calhoun, owner of Alexandria and Arlington’s Little River Yoga, stepped forward to examine the image more closely.

But no moves got even close to that complicated when the group embarked on the second half of the museum experience. Mats were positioned in two rows, separated from other museum-goers by just a few stanchions. Duke asked participants to relax as much as possible as she led them through a gentle warm-up on the floor to focus on the chakras — referencing a scroll they’d seen in the exhibit that mapped out the body.

The series ended with pond pose, which involves lying on your back with your arms stretched on the ground behind your head. It’s one of the older poses, she explained, in comparison with what they’d do next: sun salutations. The flowing series that combines forward and back bending and hip stretches is a much more recent addition to the yoga repertoire. (A book in the 1920s on the other side of that room is given credit for making it a modern-day yoga staple.)

Next up came the promised lion pose. Sitting down, Duke explained that they’d stick their tongues out while deeply exhaling. “And we roar like a lion,” she said. The goal: to move energy and find balance.

They needed that balance for what came next. Duke started to tell her students that they could get support while standing on one leg by using the wall. But then she remembered museum rules. “You can’t touch the wall, so you have to be good at tree pose,” she said, apologetically.

After a few more active postures, the yogis lay on their backs breathing while Duke read a passage about consciousness. Then she invited them to sit up, and put her palms together by her chest to offer the traditional yoga closing, “Namaste.” (It means “I bow to you.”)

But it was far from the end of yoga study for Michele Stark of Old Town, who had come to better understand the history of something she’s been doing for five years. Practicing surrounded by art was a “deeper, more meaningful experience” than a traditional yoga class, she said.

The marble jina from that first room was in Susan Levine’s head throughout the class. “It looked so relaxed, but really very aware. That’s the essence of meditation,” said Levine, who lives in Rockville. The other image she couldn’t shake: The black-and-white video of two legendary teachers, Tirumalai Krishnamacharya and B.K.S. Iyengar, that played on a screen right next to where the mats were rolled out. “It’s history looking down on you,” she said.

From the other side of the stanchions, other people were also looking down on them. On Wednesday around lunchtime, the exhibit wasn’t particularly crowded, but there were many more eyes on the Sunday morning class.

People entering the room looked at the books in the display cases, and then they stared at the class.

A group of elementary-school-age students, entranced by the soothing voice of instructor Annie Moyer, took a seat just next to the barrier. And soon, they were getting on their hands and knees into downward dog, then lying on their stomachs and pushing up into cobra. If the kids wanted to come back, a museum staffer told their parents, there are special “Art in Context” programs for families on the schedule. (There also are others for teens and seniors.)

It can be a bit strange to feel like part of an art exhibit, but Brooke Kidd, 45, founder and executive director of Joe’s Movement Emporium in Mount Rainier, didn’t have any problem with being on display.

“People need to see how easy it is, and how accessible it is,” Kidd said. “The body wants to move.”

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Art in Context: Practicing Yoga in the Galleries

Registrants should arrive 20 minutes in advance and sign in at the information desk. Several dates are sold out, but there is a waiting list, and walk-up spaces might be available. Go to the Sackler Web site to see the available dates and register. Mats are provided. Through Jan. 22. Arthur M. Sackler Gallery, 1050 Independence Ave. SW. 202-633-4880. support.asia.si.edu. $15.