NAU Researchers Study the AlterG Anti-Gravity Treadmill

AlterG treadmill 225 x 250
Maria DeCabooter, NAU Public Affairs coordinator, takes the AlterG anti-gravity treadmill on a test run. Dirk de Heer, NAU Assistant Professor of Physical Therapy, looks on.

Stepping into the opening of a deflated rubber tent that is mounted on a large treadmill does not inspire thoughts of speed or efficiency, let alone balance. But when the AlterG anti-gravity treadmill inflates into action—and you start walking, then running, at 80 percent of your bodyweight, the transformation into lightness seems almost magical.

If only pounding the pavement could feel so easy.

That's part of the point, says Dirk de Heer, NAU Assistant Professor of Physical Therapy, but it's not the only lesson to be learned from this unusual and uncommon piece of equipment, which only four years ago was being used almost exclusively by elite athletes:  "The things they were trying to achieve also make it easier for people to walk with lower impact."

Using funding from a Technology Research Initiative Fund grant, de Heer added an AlterG to the physical therapy lab at NAU's Flagstaff campus to research its effectiveness on on top athletes as well as on "all kinds of people who have difficulty walking" from stroke patients to those with Parkinson's or multiple sclerosis. For someone with a debilitating illness or injury, just the feeling of being able to take a few steps can be physically therapeutic and a crucial confidence builder. Users, who are supported at the waist by a bag of pressurized air, may choose from a digital readout of pace and percentage of bodyweight to make the painful or impossible seemingly evaporate beneath their feet.

"Body weight-supported training is not something new, but the way the AlterG achieves it is different from traditional methods," de Heer explained. Patients are experiencing the machine's potential at two student-run neuro-clinics held annually at NAU under the supervision of full-time faculty. The research is ongoing. Runners who use the machine consent to their performance and recovery data being recorded so hard science can be added to growing anecdotal evidence.

"Little is known about clinical research on the AlterG, so I think a barrier is that we're still finding out what the effectiveness of the machine is," de Heer says. "If you take 10 percent off somebody's body weight, they're going to run faster, and it's going to be easier. But how much faster do they need to run to have the same [intensity] effort?" As NAU research is beginning to show, a runner must go quite a bit faster. But there's still a benefit.

"You get a much lower impact on your legs," de Heer says. "So if you had an injury, you could still get a good workout; and if you go to 70-80 percent of your bodyweight, you could do the exact same workout as you normally do but have less stress on your body."

In February 2014, NAU physical therapy graduate student John Kline presented his initial research results with the AlterG at the Combined Sections Meeting of the American Physical Therapy Association in Las Vegas, and he will also present them in May at the American College of Sports Medicine and World Congress on Exercise in Medicine in Orlando, Florida.

--Adapted from