Wednesday, August 16, 2006

Alter-G Anti-Gravity Training - My First Hand Experience

One of the great things about living in Silicon Valley is that. occasionally, you get to be one of the first to see a technology that will clearly change everything. I had just that opportunity last week when the guys from Alter-G invited me to come down and try their anti-gravity treadmill. Yup, you read it right - an anti-gravity treadmill. After 30 minutes on this thing, I now know why former world-record marathoner Alberto Salazar has been raving about it - Alter-G presents a whole new approach to distance training.

(Ticking off the miles at 60% my body weight in the Alter-G G-Trainer)

The G-Trainer uses air pressure to support your body weight while you run. It is surprisingly non-intrusive. The only additional gear required was special shorts that "zip in" to the air chamber. Once I "zipped in", the G-Trainer took my body weight and tested the pressurization levels, and I was ready to run a few seconds later.

I punched in "80% bodyweight" on the G-Trainer dashboard, and in 10 seconds the pressure in the bubble below my waist increased until I felt 30 lbs lighter. The sensation was amazing - significantly less impact on my joints, and a floating feeling with every stride. The special shorts provided uniform support (no wedgie, that is), so I didn't feel like I had to adjust my normal treadmill stride at all. With every step, the Air Pressure Differential technology was taking 100 measurements per second and keeping the weightlessness consistent.

(Rear view of the G-Trainer; the clear windows were handy for checking posture,
and the brackets allow for pro athlete sized users)

Once I warmed up, I set the pressure to "60% bodyweight" and cranked up the speed. Before I knew it, I was running at 15 miles/hour...that's a 4 minute mile! It was fascinating that I could experience the turnover and stride length required to go this fast without breaking my body in half. Most sprinters wouldn't spend more than 5 minutes at full race pace in a season - with the G-Trainer, you could go full race pace every week.

I slowed down to a 7 minute mile and cruised for a while. My posture and alignment looked good, with no adjustment required for the G-Trainer. I pictured logging some long runs at 60% support, training my aerobic system, getting my body used to a solid pace, all without having to sacrifice my joints. It couldn't replace the long run, but I could certainly increase my mileage by supplementing it.

After my run, I talked with the Alter-G team - Sean Whalen, Brent Looney, Fritz Moore, and Eric Edelson - about the implications of such a system. Examples included:

  • Rehabilitation - with anti-gravity support, you could begin rehab sooner and be back on your feet sooner. In fact, this is why the Oakland Raiders and Golden State Warriors both have one.
  • Speed training - much like I experienced, you can train your body to know the turnover and stride length required to hit your top speed.
  • High mileage - If supplemented, one could add considerable weekly mileage. Drop your weight by 10%, you can add 10% more mileage (actually, Alberto Salazar has his runners training at 90-97%, and swears it allows 10-25% more volume, on average - check his video testimonial)
  • Obesity aid - can you imagine letting an obese person feel what it is like to be 50 lbs lighter as a start to their conditioning? Incredible pyschological power.
  • Training for the elderly - for those losing their ability to support themselves, they can still train aerobically. The G-Trainer can supplement up to 80% of your bodyweight.
Personally, I was blown away by the possibilities. Once you experience it, you'll see it really is an unfair advantage. I expect in a couple of years we will see G-Trainers in gyms, hospitals, and more.

Check out Alter-G's web site to see more videos about how it works. There are even testimonials by Alberto Salazar, Robert Gallery (Oakland Raiders), and Chase Lyman (New Orleans Saints). Alter-G is an ambitious young company, and they are planning to have G-Trainers commercially available in 2007. For you investors out there, Alter-G is currently seeking venture investment for expansion. For all you bloggers out there, help Alter-G by linking to this story!

And since we're talking treadmills, I want to point you to this video by the band OK Go. I'll never look at a treadmill the same!

- SD

[P.S. - I have no financial interest in Alter-G.]


  1. Do you think that ratio holds? 10% less weight = 10% more miles? Could you do 50% more at 50%?


  2. Wow, that must have been fun!

  3. What happens if you trip? Do you fall slowly? (ha, ha)

  4. We love your blog over at BeFittr. Is there a convenient way to contact you? We would love to discuss adding some of your content to our system to share with the community. Giving you all the credit of course. I can be reached at dhenry-at-befittr-dot-com. Hope to hear from you soon.

    Damon Henry
    Founder, BeFittr

  5. Something about this sounds funny to me...

    I am a runner and an aerospace/mechanical engineer...

    You aren't being supported by buoyancy you are being lifted by the top of pressure vessel... Are you serious when you say that the shorts are comfortable when they are supporting more than 40 lbs of your body weight?

  6. Yes, they are that comfortable. I was pretty surprised myself.

    They are compression shorts; the thin neopreene shorts often used by pro NFL linebackers. The felt like cycling shorts when I first put them on. I zipped in around the waist, and it supported uniformly across the shorts.

    One of the founders told me they just tried to break the 3:43 mile record by setting their weight at 127 lbs (the weight of El Guerrouj when he broke the record). He came up a few hundred meters short, but I thought it was a great way to test the system!


  7. I love that OK Go video! Is that all in one take?!? That must have taken months!!!

  8. Great post, Scott. Once again the bloggers scoop the running mags!

  9. Great post, Scott. I want to share this one with my peeps, so I linked it to my site.

    An aside: I grew up in Hayward and Garin Park was practically my backyard. Every time I return to visit, I make sure to get a run up in those hills.


  10. Thanks for the link, Lloyd. The more who know about Alter-G, the sooner we can get one!

    Best, SD

  11. Now if I could only get a portable model, to help get me over the mountains in my next 100-miler.

  12. The G-Trainer is quickly becoming "the" training tool. Nike Oregon Project runners, under Alberto's tutelage, have really done well.

    Kara Goucher won bronze in the 10K at the 2007 Osaka world championships, and Dathan Ritzenheim, Galen Rupp, Shalane Flanagan and Adam Goucher all qualified for the finals and showed well (top 10 all). We're pleased to be a part of their training programs.

    For more information contact us at or visit

  13. Come see what elite runners have known for the past year and a half, the G-Trainer (from Alter-G) anti-gravity treadmill will be exhibited at the New York Athletic Club from 10-23 through the NY marathon/Olympic Trials Marathon to 11/16.

    If you were following the recent world championships in Osaka, you saw Alberto Salazar’s runners (under the Nike Oregon project) do amazingly well. Kara Goucher won Bronze in the women’s 10K. Adam Goucher, Galen Rupp, Dathan Ritzenhein and Shalane Flanagan all qualified for the finals. And all use the G-trainer.

    (learn more at

    Alberto Salazar will be doing a seminar on the G-Trainer on Friday the 2nd with a presentation on how he's used and incorporated the G-Trainer as part of his training/condition and injury prevention routines. Nike runners and elite/professional runners will be training in the G-Trainer live. So can you.

    Watch for press releases, e-mails and blog entries for more details. Come see, and try the future of training and conditioning. The G-Trainer, from Alter-G.

  14. We have just purchased an Alter G G-Trainer for our Phoenix facility. Any athletes in the area are welcome to come try it out.

    Mychal Brosamer

  15. How much does it cost to purchase one, plus how much energy does it use?

  16. I don't know about the energy usage (good question!), but I do know they cost as I just inquired about it myself.


    If anyone has that much money they don't know what else to do with, I'm extraordinarily interested in getting one of these. ;)

  17. Didn't mean to have that be annonymous. Sorry!

  18. wow. I want one! $75k ouch.

  19. I heard about this machine a while ago when an recovering basketball player was using this to get back into shape. I guess it takes all pressure off and makes you lighter? I'm not really sure, but it looks really fun to run in..

  20. $75K? For that price I would want cable tv and a foldout mattress since I would need somewhere to live after having sold my house to afford one.

    Unfortunately many people have not been told that running on a treadmill can actually interfere with the bodies ability to run outside. This article explains how:

  21. A recent podcast on Endurance Planet with Dathan Ritzenheim quoted him saying "I bought one for my that they are about $30k, it's something a two elite household can justify".

    Sounds like it's quite a bit cheaper these days.


  22. That is so cool you got to run on that anti gravity treadmill

  23. That is so cool you got to run on that anti gravity treadmill!

  24. My PT has the treadmill also and when he got it there were only 2 in Arizona. Now, I'm sure there are more. It was awesome being able to run while injured.

  25. Try looking into the Glidetrak, it's only $3249.00 and does the same thing as the Alter G-seriously. Good blog.

  26. What a interesting concept great that it benefits elderly athletes


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