Treading lightly

August 18, 2011

I first heard about the Alter-G “anti-gravity treadmill” in August of 2006 via Scott Dunlap’s blog. Yesterday I tried it myself for the first time. I guess that puts me about five years behind the cutting edge of running technology, which sounds about right. Anyway, Scott did his usual thorough job in writing about the Alter-G, so I have only a few notes to add.

I haven’t run more than one mile at a time since my Achilles surgery in March; however, upon reducing my effective body weight to 60-80% of normal, I was able to comfortably cover the treadmill equivalent of two miles. This is one of the main uses of the Alter-G: low-impact exercise during recovery from injury or surgery. However, it also lets overweight people run with less stress on their bodies. Ditto for exercise addicts who wish to “train through” their pre-race tapers while giving their muscles and joints a break. Dr. Larry Maurer, who supervised my session, said that he uses it as a “torture device” in his own training: he’ll run to exhaustion at his normal body weight, then reduce the load to 90% of body weight and run to exhaustion again, then drop to 80% of body weight and go again…. And while running to exhaustion on a treadmill can be a bit dicey, the inflatable compartment can catch you if you start to fall.

The feel of running in a low-gravity environment is interesting. At 60% of my body weight, I felt like an overgrown “Jesus lizard,” skimming across the surface without fully planting my feet. At 75%, I had the sensation of running normally but effortlessly, as if warming up before a big PR race. Then I went up to 95%, which seemed like the gravitational equivalent of hitting the wall. Never in my life have I felt as fat as I did at that moment.

The compression shorts that tethered me to the anti-gravity chamber were reasonably comfortable, but there’s no mistaking the fact that you’re running in a bag on a treadmill. This is definitely a device for people who are highly committed to their rehab and/or training. For those who wonder whether the Alter-G might be right for them, Dr. Maurer offers a free trial session and various multi-session packages that work out to about $17 per hour. (Contact information is available on his website, rundoctor.com.)

Thanks to Matt Cuellar of Alter-G and Dr. Maurer for giving me the opportunity to do this test run. I may be back someday — perhaps after I lose some weight the old-fashioned way.


  1. Did you try and run a 4-minute mile? 😉

    • Nope — the treadmill only goes up to 12 mph….

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