NASA Glenn employee Beth Lewandowski demonstrates space travel exercises on a treadmill. (Photo by Kevin Kelley.)

NASA, Cleveland Clinic team up to help astronauts
By Kevin Kelley
Westshore
Published Aug. 30, 2006

Trainers and coaches sometimes use the phrase ‘use it or lose it’ to refer to maintaining muscle strength. Well, it turns out that is true nowhere more than in space.

Over four-and-a-half decades of space travel, researchers have learned that loss of bone and muscle strength due to weightlessness can be significant for just short periods in space. This phenomenon remains a present problem in mankind’s future exploration of space.

Engineers at NASA’s Glenn Research Center, and the Cleveland Clinic Lerner Research Institute’s Biomedical Engineering Department, Cleveland, Ohio, have been working on a possible solution. They have designed, built and are now testing a device called the Enhanced Zero-gravity Locomotion Simulator to simulate how astronauts exercise during space travel.

The device consists of a treadmill flipped vertically 90 degrees. Test subjects are then strapped into the harness and suspended from the ceiling in a horizontal position while they walk or run on the treadmill. In this position, there is no gravitational force between the runner and the machine.

The exerciser, in the harness suspended by cables, runs ‘on’ the treadmill. A system of cables and pulleys, controlled by computers, pushes or pulls the subject toward or away from the treadmill to simulate various levels of gravity. When the device is programmed for one-sixth of Earth’s gravity, the subject appears to ‘moon walk’ on the treadmill, because the moon has one-sixth of the Earth’s gravity.

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View a short video clip of the eZLS treadmill in action.

Beth Lewandowski, a Glenn employee who ran on the treadmill in a demonstration for local media Aug. 23, said “It just kind of feels like I’m laying down. When I don’t have any loading (applied force) on me, it’s very comfortable. When I’m loaded, I can definitely feel a force pulling be back toward the treadmill ... It’s a force I feel on my hips and shoulders pulling me horizontally toward the treadmill.”

This study specifically focuses on the design of the exercise harness that astronauts wear like a backpack while running on the International Space Station treadmill. The key to the success of load-bearing exercise, such as treadmill running, is the application of gravity replacement loads to the crew member via a subject load device coupled to the body by a harness.

Astronauts are currently allotted up to 2.5 hours per day in exercise activities. However, crew feedback has indicated the harness frequently causes chafing and discomfort.

“In this study, we are using the eZLS to understand how we may help astronauts exercise more comfortably in space,” said Gail Perusek, NASA Glenn project manager for the eZLS, and a resident of Lakewood. “The end results of this study will help show us what design factors affect harness comfort, so we can build better equipment more suited to achieve the greatest benefit for crewmembers.”

The prototype harness, developed by Cleveland Clinic utilizing backpack technology, and the most recent harness developed for astronauts by NASA, will be evaluated to determine how they can best be used to optimize exercise performed and thereby maintain bone and muscle mass as well as cardiovascular health.

But the study also has application in modern medicine. Peter Cavanagh, Ph.D., D.Sc., chairman of the Cleveland Clinic’s Department of Biomedical Engineering and co-director of its Center for Space Medicine, reported the space shuttle astronauts can lose up to 20 or 30 percent of the muscle strength after just 10 days in space. A study of cosmonauts aboard the Russian Mir space station revealed a rate of bone atrophy — especially in the hip and bottom of the spine — of up to 2 percent for every month in space. This compares to 2 percent a year for post-menopausal women, he said.

For astronauts, Cavanagh believes exercise is not the only solution. However, drugs which fight osteoporosis, which are designed for seniors, stop bone cell turnover. Giving such drugs to healthy, young astronauts could have harmful effects, he said.

But Cavanagh said research on exercising astronauts promises benefits to the rest of us on the ground.

“There are tens of millions of people with osteoporosis,” Cavanagh said, “and I think many of them want to know: ‘Are there alternatives to drugs?’ ‘Will exercise be a suitable component of a therapy for osteoporosis?’

“We haven’t thought of exercise in terms of thinking of it as a drug, in terms of a dose and a strength,” Cavanagh told West Life.  “That’s what we always think of with medications. But we don’t really give accurate prescriptions of exercise to counter bone-muscle loss.”

Cavanagh, who has been studying space medicine since the early 1990s, said he hopes his research will “formalize and clarify the issue of how exercise can contribute to the maintenance of bone mass in people on Earth.”