What is an Anti-Gravity Treadmill?


If you’ve ever looked into buying a treadmill, no doubt you’ve seen many different types. One type you may have come across is an anti-gravity treadmill.

But what is an anti-gravity treadmill, and how does it work? This unique device is a treadmill in an air bubble, which uses air pressure to “de-weight” the runner.

Unfortunately, it’s not something most people can go out and buy for their home gym. It’s a super-specialized type of treadmill designed more for recovery than performance. They’re more likely to be found in a physiotherapist’s office than in a gym!

That being said, if you can access one – like an AlterG Treadmill – it’s ideal for runners recovering from injury as a way of getting in the miles without the impact.

Here’s what it is, how it works, and when to consider using one.

What is an Anti-Gravity Treadmill?

Everyone already knows what a treadmill is. However, an anti-gravity treadmill is much different from a conventional treadmill.

In appearance, the anti-gravity treadmill looks like a regular treadmill that’s been placed in a gigantic capsule. It looks kind of spacey… This makes sense, as it’s created from NASA technology originally designed to keep astronauts fit.

Technically, it counts as rehab equipment and is more likely to be found in a physio or rehab setting than a gym.

How Does It Work?

These treadmills use technology patented by NASA, originally designed for astronauts.

The tech for current models has been reversed—in the beginning, it was designed to add extra weight to an astronaut’s frame while in space so they could train with resistance that felt more like gravity.

Anti-gravity treadmills reverse this to reduce your body weight, allowing you to exercise without less impact on your bones and joints. Your lower body sits in an airtight chamber with specially designed shorts. Built-in tech changes the air pressure to simulate running with less weight.

Once you’re sealed in the capsule, the system will calibrate to your specific body metrics. Aside from the strange act of zipping yourself into an airtight chamber, you use the anti-gravity treadmill exactly like a normal treadmill. Select your running speed, incline, and weight percentage you want to remove.

Despite its funky-sounding name, you don’t actually float in the chamber. While the impact with the treadmill belt is somewhat reduced, you maintain constant contact with the machine.

The anti-gravity treadmill also shows some unique metrics you won’t find on your normal ones, like stance time, strike force, and stride-length symmetry.

Benefits of Running On an Anti-Gravity Treadmill

If you can train on an anti-gravity treadmill, here are a few benefits you’ll enjoy.

Injury Rehabilitation

This is the primary function of these machines, so your greatest chance of getting on an anti-gravity treadmill is actually when you’re going through injury rehabilitation. It allows you to stay fit and maintain your regular running routine, just with significantly less strain on the joints and muscles.

This can hugely benefit runners recovering from serious injuries like fractures, tendon or ligament tears.

The reduced pressure allows the injury to heal without sacrificing your training. Research shows that athletes who used this device as part of their recovery would recover, on average, two weeks faster than those who didn’t use it!

Other conditions that can be healed faster with anti-gravity training include:

Allows for Controlled and Gradual Progression

Post-injury rehab relies on controlled progression back to weight-bearing running. If you get back into your regular activity level too quickly, you risk reinjuring yourself and potentially causing worse damage.

An anti-gravity treadmill allows you to reintroduce weight-bearing as the injury heals slowly. With a knowledgeable operator, you’ll be able to strengthen your joints and bones as they increase weight-bearing in a way appropriate for every healing stage.

Gait Training

Without the full impact of your body weight on your feet as you run, it’s easier to pick up and focus on fixing gait abnormalities.

Training on an anti-gravity treadmill allows you to correct poor form and biomechanical issues and develop new habits before returning to your full weight.

Reduced Impact

One of the main reasons the anti-gravity treadmill is so great for injury rehab is that it reduces impact on your joints in a BIG way.

Retired Staff Sgt. Jesse Whitmier exercises in the NASA-developed anti-gravity treadmill. Courtesy of the US Air Force

You can continue to train at a high intensity with little to no impact on your joints, keeping you fit without aggravating existing injuries or having the potential for new injuries.

Injury Prevention

When running on an anti-gravity treadmill, you won’t be as prone to injuries.

The constant repetitive action of running can easily lead to overuse injury, but with the impact removed from running on an anti-gravity device, this isn’t a factor anymore.

In fact, it can help you build muscle and strengthen your joints to the point where your injury-prone areas are strong enough to withstand regular training without getting hurt.

Performance Enhancement

You can use an anti-gravity treadmill as a training tool, although it’s pricey and harder to find. It’s especially handy for distance runners who want to get in the miles without the wear and tear on the joints.

The cumulative effects of reduced injury, strengthened muscles, and reduced joint impact can make a big difference in improving your form and boosting your performance.

Exercise for the Obese

The anti-gravity treadmill isn’t just excellent for injury prevention but also an excellent way for obese people to start getting in shape.

The significantly reduced body weight means there’s far less impact on the joints, making it a much safer and more comfortable option for those trying to lose weight.

Who Can Use an Anti-Gravity Treadmill?

You can typically book an anti-gravity treadmill session at a physio, biokinetics, or other therapist location. Runners actively going through rehabilitation should look into booking sessions.

Getting Started On the Anti-Gravity Treadmill

It’s quite a process to get going on the anti-gravity treadmill. Unlike a normal one, you can’t just step on and go. You’ll need to wear a special pair of neoprene shorts, which features a skirt around the waist that gets zipped into the capsule’s opening.

You’re effectively tethered to the treadmill with your feet on the belt. Once the treadmill is on, it’ll calibrate to your body weight and size to properly reduce your weight.

It’s up to you—or your therapist—to decide what percentage of your body weight you want to “unweight.” Most machines give you options from 20 to 100 percent.

For example, a 160-pound person who chooses to run at a 25 percent body weight reduction will feel like they’re only carrying 120 pounds in the chamber. This can make a huge difference!

From there, simply select your running speed and incline like you would on a normal treadmill, and get running!

How Often Should You Run On an Anti-Gravity Treadmill?

There’s no hard-and-fast evidence to suggest the optimal training load on an anti-gravity treadmill. Still, it’s generally accepted that just one session per week can have positive effects.

You’ll effectively give your joints a “day off” while enjoying the cardio benefits of a good run. Just one extra day off per week for your joints can make a big difference, especially in preventing overtraining.

You can bump it up to 2 sessions a week—one long run, one short run—if you’re training for a specific event or race.

Don’t make the mistake of switching out all your runs for anti-gravity sessions. Your joints and bones still need weight-bearing exercise, so you’ll be doing more harm than good if you completely avoid running on harder surfaces.

Can You Buy an Anti-Gravity Treadmill?

Yes! If you’re desperate to have one of these devices for yourself so you don’t have to go to the physio every time, you can buy one. However, depending on its quality, it’ll set you back anything from $35,000 or more.

Your best bet is to find a facility near you that offers sessions and price them. They’re not likely to be cheap—but if you’re serious about your sport and want to reap the many benefits of anti-gravity training, it’s worthwhile trying.

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Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.