How many athletes have let lingering pain in their lower body prevent them from participating in that next big race or event? Or how many have said, “I would run to get this weight off if my knees didn’t hurt so much”?
What if reducing your weight by 15 percent would allow you to run pain-free? That’s the beauty of the AlterG anti-gravity treadmill, a piece of therapy equipment developed by NASA scientists to plan exercise programs for their astronauts.
The AlterG looks like a regular treadmill, except for an attached huge moonbounce-like bubble surrounding the running area. Users wear specialized neoprene shorts that zipper airtight into the bubble. By using differential air pressure technology, the bubble fills and lifts the person to unweight them down to 20 percent of their bodyweight. Punch the numbers into the control panel and feel the lift off—literally, you are taken onto your toes.
The treadmill begins and you have to adjust your gait and balance to the new lighter you. After you have the hang of it, increase the speed and experience what it’s like to run a 6:00 mile again—or for the first time. The hardest part of this run, unlike most, is stopping. Reducing the air pressure and returning to normal weight brings back the full effect of earth’s gravitational pull and all its associated side effects, especially increased joint compression.
Athletes or regular old folks of all types can use the AlterG for functional weight-bearing exercise (walking, running) much sooner in their rehabilitation program following injuries or surgeries. Therapy patients using the AlterG at our Penn Therapy & Fitness at Rittenhouse location describe the experience as like running on the moon. It’s not quite as good as the moon, since 83.3 percent of your body weight is eliminated there—still, that’s pretty close and for athletes, a much better alternative to weeks on a stationary bike or elliptical.
Rehabilitation specialists fortunate enough to have an AlterG can offer the athlete or laborer a jump on recovery. By unweighting the patient during running or walking, ground reaction forces are reduced (this is good), as is muscle activity (this may or may not be good). By increasing the treadmill speed, muscle activation is increased without the negative joint forces. This is one of the unique qualities of the AlterG—it allows decreased weight-bearing but increased speed training.
Reducing the weight and the nasty compressive forces associated with it allows a person to exercise pain free and pile on the miles. If you really want to experience the relationship between unweighting and pain, increase the weight reduction by one to two percent at a time and see if your lower body injury feels any better. At approximately 8-12 percent, the pain will disappear.Decrease the unweighting by three to four percent and your pain returns.
This can be very cool to experience. More importantly, it will motivate you to exercise and keep your body in shape. A 2011 study at Texas A&M University concluded that dieting women who used the AlterG were more motivated to exercise and demonstrated improved body fat loss and free-fat mass compared to those who used a standard exercise program.
For the recovering athlete, non-astronaut or just your average person trying to lose weight, the AlterG may be just what the doctor ordered—even if you don’t live on the moon.
Marty Kelley is an advanced clinician and site manager for Penn Therapy & Fitness at Penn Presbyterian Medical Center. He is the past-president of the American Society of Shoulder and Elbow Therapists. He writes about therapy technology and new research.
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