It took a while to get to downward-facing dog.
First, the eight men and women at a recent class at Tarana Yoga Studio in Minneapolis engaged in "joint warm-ups," circling their wrists three times in each direction.
Next, they carefully moved into standing poses, keeping a chair at the edge of their yoga mats to steady themselves as needed.
Finally, their bodies limber, they tilted their hips back with hands and feet planted on the mat — expertly performing the challenging downward-facing dog pose.
The minutes ticked. No one flinched.
"Respect where your body's at today," instructor Amy Samson-Burke told the class for people with Parkinson's disease. "Be where you are."
Held twice a week, the experimental class is part of a study being conducted by the University of Minnesota to find out if yoga is an effective tool for managing Parkinson's disease.
Corjena Cheung, a professor at the university's School of Nursing, said she hopes to build on her previous research examining yoga's effects on osteoarthritis. The results of that study were so promising — increased mobility and less fear of falling — that she wanted to explore whether yoga could help with Parkinson's, too.
Yoga is one of the leading alternative therapies used by Americans, according to a National Institutes of Health survey on alternative medicine use.
Cheung's work would add to a growing body of science on the popular practice's impact on Parkinson's disease — a degenerative brain disorder involving the nerve cells responsible for voluntary movement. The condition is diagnosed in about 60,000 Americans a year. Tremors, a shuffling walk, muscle stiffness, depression and dementia are among the symptoms.
The focus on yoga as a possible therapy for Parkinson's stems from its gentleness and its emphasis on breathing, strength and flexibility.
A Kansas University Medical Center study found a visible reduction in tremoring and improvement in the steadiness of gait in people who participated in yoga sessions, according to the American Parkinson Disease Association. In her osteoarthritis and yoga study, Cheung found that participants were better able to cope with their symptoms by doing yoga rather than aerobic strength exercises.
For this study, she recruited participants through local support groups for people with Parkinson's. It was an easy pitch.
"People are very motivated," she said.
There are 20 people involved in the study. Half of them were told to make no change in the way they manage their symptoms. The others are doing yoga. Cheung will measure their stress levels by giving them a blood test and checking for the presence of certain stress hormones. She also will examine their motor functions, checking their range of motion, stride length, balance and gait.
Five yoga experts who had experience teaching yoga to people with physical limitations helped design the hourlong classes, which will go on for six months. Cheung said she suspects that by the end of the experiment, the results will show that yoga improves motor function and reduces stress for people with Parkinson's.
But for now, all she knows for sure is that the participants seem to be enjoying themselves.
"The fact that yoga includes both physical as well as the breathing and relaxation piece, I think that has added benefits for people with Parkinson's," she said. "They are suffering from not only the physical limitations. Yoga teaches them how to cope with the disease and work with what they have and build on it."
The classes start out with slow, basic exercises done sitting, standing or lying down. Gradually, the participants build up to more difficult exercises and poses. In addition to the usual yoga props of a mat and block, there are chairs to help maintain balance and small sandbags to help control hand tremors.
"They can use the prop to help them get to where the ideal pose is for them," Cheung said, adding that she's heard that some of the people are now doing yoga at home, too.
Though the study won't wrap up until December, the participants have reached their own conclusions about yoga therapy.
Jerri Smith is encouraged. The 58-year-old St. Paul woman is new to yoga but not to Parkinson's. She was diagnosed with the disease six years ago.
She said she agreed to participate in the study because she wanted to see whether yoga would help her symptoms.
"It's good to calm my mind down," she said. "Also, I have a lot of [muscle] cramps and spasms. My back is really stiff."
After a session last week, she reported that her muscles no longer feel so tight.
Bob McGonigal, 72, balanced on one leg and bent the other to form a Figure 4. He held the pose, standing perfectly still.
"That's called the 'tree pose,' " he said. "When we first started, I couldn't do that."
He, too, came to the study in search of alternative ways to manage his Parkinson's. The Bloomington man was diagnosed in 2010 and has tremors in his forearms and upper arms.
Steve Knudsen, 69, of Burnsville, said he's found that his body is more flexible after an hour of yoga. Recently, he left class and noticed that he didn't need to take his medications for Parkinson's for an hour because he felt so good.
"There are a lot of possibilities with this," he said.