|Washington (AP) - NASA, worried about astronauts
who go flabby in space, is studying how to adapt weight training so it can be done in
weightlessness. A device that will let astronauts do the orbital equivalents of weight
room workouts "will definitely fly within 18 months, at the latest, " said NASA
exercise expert Mike Greenisen of the Johnson Space Center in Houston.
multifunction exercise machine would let astronauts work against hydraulic pressure while
doing exercises similar to those that require weight slacks on Earth, according to
Greenisen, manager of the exercise countermeasures program for the National Aeronautics
and Space Administrations NASA wants exercises that stress the body from the shoulders to
the feet, Greenisen said. Astronauts would press against the machine's yoke-like collar.
The program's goal is to give astronauts a workout equivalent to a day's worth of
gravitational pull on earthbound bones and muscles, Greenisen said. It's based on a
mathematical model, which can be fitted to the individual astronaut, of how much force a
day's worth of gravity would be, he said.
In weightlessness, it's no problem to be out of shape, Greenisen said: "The human
body adapts perfectly to the space environment." What happens after space is the
problem. Astronauts' muscles must be strong enough to reencounter gravity -- either the
Earth's or that of some other planet, Greenisen said. Astronauts typically end space
shuttle missions weak and wobbly under the combined loads of their 75-pound launch and
entry suits and their own body weights, he said.
Another purpose is to retard the loss of bone mineral density. Without the stress of
gravity, bones lose calcium, as people do when they are confined to bed. If the bones are
stress-free long enough, the weakness can increase the risk of fractures. Finding exercise
for long flights will be crucial for interplanetary flight, Greenisen said. Unless
astronauts can stay strong enough to function after they re-encounter gravity, those
missions can't go forward, he said.
And stationary bikes, rowing machines and treadmills, all tried in space, haven't been
able to do the job. These machines are primarily valuable for cardiovascular conditioning;
they make less powerful demands on bone density and muscle power. So NASA, working with
Ariel Dynamics, Inc. of Trabuco Canyon, Calif., has created a prototype resistance
exercise machine. The device, about one foot square and two feet high, is made of steel
and weighs about 70 pounds, but the weight could be dropped below 50 pounds if it is made
of titanium, Greenisen said.
So far, the device has been tried by astronauts and scientists who worked out in a NASA
plane as it dived, Greenisen said. These tests in 20-second bursts of free-fall
weightlessness indicated the machine could create enough force to mimic gravity, he said.
Greenisen awaits the scheduling of a space shuttle trip in which to test the device. He
wants to answer such questions as whether one session of exercise will do the
gravity-imitating job or whether exercise should be scheduled in smaller segments
throughout the day. The problems of bone and mineral loss in space are the same ones faced
on Earth by people confined to bed, So NASA also has been studying how to exercise while
For now, the equipment developed with Ariel has the inside track to space partly
because its hydraulic equipment requires less area. Greenisen said. It would not need an
air compressor that Kaiser's pneumatic equipment would use, he said.
End Advance for Monday, April 17, and Thereafter