It’s Time to Try Defying Gravity. On an AlterG Treadmill.

All smiles despite five miles at 10K pace

As journalists, Dimity and I get to do a lot of nifty things. I’ve gone to Kona, Hawaii, to watch the Ironman World Championship triathlon. Dimity climbed Mt. Kilimanjaro for a magazine assignment. Dimity and I get to test a bevy of gear—from sports bras to GPS devices—for reviews. Dim and I got to run the Nike Women’s Marathon, the experience that launched The Book. The latest on the list of we-know-we-got-it-good opportunities: I got to test an AlterG treadmill last week. The timing couldn’t have been more ideal, with my plantar fasciitis-addled foot and my out-of-my-routine visit to my parents’ house in Connecticut. While I’d eased back into running slightly with two short, flat runs, I was chomping at the bit to push myself and work up a serious running-induced sweat.

So last Wednesday, I eagerly arrived at the swanky new Equinox gym in Greenwich. After some questions and a hurt-so-good rolling from The Stick by Coach Frank, Coach Sean got me ready for the AlterG. If you’re unfamiliar with the treadmill, it’s literally a space-age device (the patent it’s developed on was originally used by NASA) that allows injured, pregnant, obese, or infirm people run (or walk) with up to 80% of their body mass “unweighted.” By lightening the load, you can exercise without the typical jarring and pounding. Like I said, perfect for my injured paw.

Marathon world-record holder Paula Radcliffe, pregnant, on her AlterG in her daughter's room

I shimmied into tight bike shorts attached to a gasket-like skirt, then stepped into an opening on the treadmill. Coach Sean helped me get zipped in, making an airtight seal from my waist down. Then Sean flipped a switch, and air was forced into the pressure-controlled chamber around the lower half of my body. The machine determined my weight, then Sean dropped the setting from 100% (full body weight—gravity in everyday life) to 50% (as if I weighed half of my 168 pounds). Alas, I didn’t suddenly feel svelte, but when Sean had me start walking, then picking up the pace to a run, I bounded along the treadmill like I was about halfway to the moon. It was similar to the weightlessness you feel in a pool, minus the water.

Because I was zipped in, I couldn’t pull a George Jetson (go flying off the back of the ‘mill), which was reassuring. Sean and I chatted as I ran, and we played with the percentage and speed. Because my body weight had been cut in half, I was able to sustain a faster pace than I typically would—yet the heart rate monitor strapped around my chest showed my body wasn’t red-lining. Even when we increased the speed to my fastest mile time ever—6:37-minute/mile pace—my heart rate was only 142 beats per minute. What a kick!!

For sh#@s-and-giggles, we reduced my weight to 80%--the most assistance the AlterG will give you. (Too bad the weight reduction isn’t permanent. Sigh.) I had to seriously work to have my feet touch the treadmill belt. Even back at 50%, my stride felt different—I landed more on my forefoot, and I could feel my glutes and hamstrings working harder than usual. (Proof: For two days after the AlterG, my glutes and hammies proclaimed their presence. In a good, exertional way, not an injured way.) The unweighting didn’t make my foot feel magically better--I could still feel my right foot had a slight “issue,” but it didn’t feel like the pain I’d felt on descents or even flat pavement on my outdoor runs earlier in the week.

My original goal was to run for 45 minutes—which would have been my longest run in more than a month—but as I neared 5 miles, I figured that was a good place to stop. (One of my mottos in life is, “End on a high note.”) The console read 39:21 as Sean unzipped me to release me from the now-unpressurized chamber. I toweled sweat rivulets off the back of my neck and forehead. It was the best workout—and fastest five miles—I’ve run in ages.

Some facilities with AlterG treadmills let the public use them for a fee. To find places near you, go to and enter in your zip code.

16 responses to “It’s Time to Try Defying Gravity. On an AlterG Treadmill.

  1. How awesome!! Can’t think of a better pair to test out the best-of-the-best/newest stuff and tell us all about it!!

  2. Wow, I really could have used one of these when I was having all my hamstring problems before running in the Indy mini. That certainly would have helped my training a lot. Oh well, I wonder if they rent them out to people who are in recover.

  3. Nice! I haven’t seen anything like that in this small town and am dreaming that one will work its way here. These days, it would come in handy for my finicky limb.

  4. I’m so jealous! Always wanted to try one of these (especially at the height of my tendonitis issues) but couldn’t find a place where it was affordable to use it!! How cool that you got to! Thanks for sharing the experience with us!

  5. That’s a very cool space-program gizmo. I love the pic of runner (astronaut?) Paula Radcliffe with this mini spaceship crammed into her kid’s room, trying to get a run in while her daughter is interested only in the water bottle.

  6. That machine is awesome! Wish I would have known about them earlier in my pregnancy…there probably aren’t any in Western PA though.

  7. I was lucky enough to try one too when we went to Canada for 3D Gait Analysis at Fit Physiotherapy. It was amazing to run like I was 80 lbs! I couldn’t believe how fast I could go-the stuff of dreams for me. The PT told me they cost about $37,000. Does my daughter really need to go to college?

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