Like Running on Pluto! Testing an Anti-Gravity Treadmill

Recently, I had the opportunity to hop on an AlterG treadmill: a treadmill that uses a vacuum to alter the effect of gravity on your body. You can adjust incline, speed, and even the percent of your body weight as you run, and there is a video display that shows your legs from different views. To get into the vacuum, you’re zipped into a chamber while wearing neoprene shorts. It’s a bit warmer than running on a regular treadmill because of the lack of air around your bottom half, but not unbearable.

People use the AlterG when they’re returning to running from injury, doing speedwork at lower impact for high volume runners, reducing the overall impact of pounding during runs, or sometimes (like for me), just for fun. Actually, I found it could be a good tool for working on increasing my run cadence.

With the ability to adjust the percentage of your body weight, you can really pick your planet. I didn’t go as low as Pluto’s 7% of Earth’s gravity, or even Mars’s 38% — I kept it more in the Uranus space of 89%. I did go down as low as 60% for a few minutes just to see what it would be like. I could tell that I was “lighter” because I was able to increase both cadence and kick without feeling like I was dying.

For the most part, I was interested in keeping it between 75% and 80% of my body weight to see what different paces would feel like if I was able to lose the extra weight I carry. What would my running potential be? Turns out that about 3 min/mile faster than my easy pace would be pretty comfortable.

AlterG sessions are typically 30 minutes long. I used one at the St. Vincent Sport Performance (SVSP) in downtown Indianapolis, where it costs $25 for a 30-minute session. This week was Sport and Human Performance Week at SVSP, so the session was free. When I arrived, a staff person helped me get into a pair of shorts and into the treadmill (definitely IN, not ON). Then she explained how it worked, what I could control, and how to stop.  She walked me through calibrating the machine to my weight and explained that what I was feeling (being slightly lifted off the treadmill) and hearing (popping noises) was normal. Once I was going, she brought me a towel and left me to run, but checked on me periodically. When I was finished, she helped me get out and said she would take care of wiping everything down and putting the shorts in the wash pile. She even took pictures for me!

I am going to talk to my coach about how we might use AlterG sessions as part of recovery or taper in the future, or for sessions focused on improving cadence and kick. My cadence is always higher when I run faster and with the help of the cameras, I was able to tell that my kick improves with speed as well. It does feel weird, but like most training tools it is useful and gets less weird the more you use it.

Have you used an AlterG treadmill for recovery or performance? What did you think?

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  1. hmmm not a fan of treadmill but this one is my favorite during an injury. I used after hip surgey. I am hoping not to have to use it ever again…. I love running outside…..

  2. A few years ago I had access to an AlterG in the Special Ops gym across the street from where I worked. Since those guys were more into the weights, it was always open, so I started using it for a weekly speed session. LOVED it. I kept the weight at 90-92%, but it was amazing the difference it made. I felt like I was flying, and like you said, it really helped with turnover. Made me think that if I just lost weight and weighed that much naturally, I’d be that much faster… unfortunately it doesn’t exactly work like that!

  3. I used it coming back from an injury, and I was so thankful to be able to run at all, despite highly disliking the treadmill. I was floored by how much easier running was at 80-90% of my body weight!