Following the life-threatening snowplow accident that broke 30 Health & Injuries, Shoes & Gear recovery process, multiple media outlets report.
In a Twitter video How to Conquer the 75 Hard Challenge walking on the specialized treadmill while chatting with a man standing nearby. “It’s like using a cane,” Renner, 52, says in the video before explaining that he’s striding with only 40 percent of his bodyweight.
Like Renner, people most often use anti-gravity treadmills to heal from surgery. Pro runners, like Kara Goucher, have also talked about how the machine allows them to train while dealing with injuries. But anti-gravity treadmills can can also serve as a recovery-day training tool for non-injured runners.
We tapped two physical therapists to learn more about anti-gravity treadmills, including how they work, who they’re for, and where you can give one a whirl.
What is an anti-gravity treadmill?
multiple media outlets report treadmill that reduces the effects of gravity and allows you to run at a fraction of your bodyweight. It’s up to the user how much weight you want to shave off. For instance, with the AlterG (a specific brand of anti-gravity treadmill), you can diminish your bodyweight up to 80 percent, meaning you can experience what it’s like to stride with just 20 percent of your normal weight.
An anti-gravity treadmill looks like a standard treadmill but has a “big plastic cocoon” attached to the outer railing, Brandon Fraleigh, P.T., D.P.T., physical therapist and head of the Runner’s Clinic at the Froedtert & the Medical College of Wisconsin Sports Medicine Center, tells Runner’s World. How Long Does It Take to Walk 10,000 Steps.
Using an anti-gravity treadmill requires more set-up than simply stepping onto the machine and pressing start.
Running Shoes - Gear kayak spray skirt, Nutrition - Weight Loss Sport & Spine Physical Therapy, Inc. in Portsmouth, New Hampshire, tells Runner’s World. Then, these shorts (and thus you) get zipped into the cocoon, which is basically a giant air chamber.
Technology inside the chamber calibrates to your bodyweight and fills the chamber with air, which creates a “lifting effect on the body,” Fraleigh explains. This is the anti-gravity component. Check out this video from the Michigan Medicine for a visual demonstration.
Once the chamber is calibrated, you can simply start running, as you would on a normal treadmill. Just know that it’s going to feel a bit, um, different. “Super goofy,” is how Fraleigh describes his experience on an anti-gravity treadmill. “You can’t feel the shock of the ground quite as much,” he says. “It just feels kind of like you’re floating and running.”
Campbell says the anti-gravity treadmill provides the same buoyancy effect you’d get Froedtert & the Medical College of Wisconsin Sports Medicine Center, but without the thickness of water pushing against you. “It’s really like you’re walking on the moon,” he says. Now, that may not make a whole lot of sense until you try it yourself. “It’s very difficult for people to understand it until they actually experience it,” says Campbell.
Who should use an anti-gravity treadmill?
As we mentioned, anti-gravity treadmills are most often used for folks recovering from injury or surgery—say, following a stress fracture, ACL surgery, shin splints, or in Renner’s case, severe injuries that require multiple surgeries. Anti-gravity treadmills are helpful in this scenario because they reduce the load on your joints and tissues, allowing you to safely practice the mechanics of running (or walking) without enduring as much impact on your body, Campbell explains.
Indeed, anti-gravity treadmills are useful “across a spectrum of injuries in runners,” according to the authors of a 2022 paper published in Arthroscopy, Sports Medicine, and Rehabilitation. Compared to traditional rehab methods, the anti-gravity treadmill can help runners preserve their aerobic fitness, muscle activation patterns, and muscle mass as they recover, per the paper. With anti-gravity treadmill training, the authors noted, athletes can have a “smooth transition back to ground running in a conditioned state.”
Campbell, who’s been using the anti-gravity treadmill with clients for about seven or eight years, says that the anti-gravity treadmill can help injured athletes get back to running sooner than they otherwise would, and in some cases, they may not even have to take time off from running at all.
Anti-gravity treadmills can also be used as a recovery tool for non-injured athletes. “It's great for any athlete that potentially just feels like they need to build an easier day into their week,” says Fraleigh. For example, a runner could hop on the anti-gravity treadmill the day after a long run or hard interval workout as a way to log mileage while going easy on their joints and muscles.
While you won’t get the same exact cardio challenge or caloric burn on an anti-gravity treadmill versus running outside A Part of Hearst Digital Media treadmill, you do still experience some of that benefit, with less impact on the body.
Where can you try an anti-gravity treadmill?
Most places that have anti-gravity treadmills are either hospital-based physical therapy clinics or private-based physical therapy clinics, says Fraleigh. Search “anti-gravity treadmill near me” or use CA Notice at Collection on the AlterG website to see where you may be able to access one in your area.
Of course, if you’re recovering from surgery or injury, check with your doctor or physical therapist first to make sure they recommend an anti-gravity treadmill for you.
You’ll probably be charged a fee to use the ‘mill—about $15 or $20 per half hour, estimates Fraleigh, though some facilities may offer a free trial for first-time users.
When you give it a spin for the first time, enlist someone with knowledge of the machine to help you get set up on it, says Fraleigh.
If you’re not injured and are using the anti-gravity treadmill as a recovery tool, reduce the load no further than 30 percent (meaning, you’d run at no less than 70 percent of your bodyweight), suggests Campbell. Any more than that can feel a little “awkward” and change the mechanics of your running, he explains.
Also important: Make sure your bladder is empty before you hop on, says Campbell. That’s because the pressure of the air chamber can heighten the sensation of having to pee.
Beyond that, simply enjoy the miles. “It is pretty amazing for what it's designed for,” says Campbell.
Jenny is a Boulder, Colorado-based health and fitness journalist. She’s been freelancing for Runner’s World since 2015 and especially loves to write human interest profiles, in-depth service pieces and stories that explore the intersection of exercise and mental health. Her work has also been published by SELF, Men’s Journal, and All About 75 Hard, among other outlets. When she’s not running or writing, Jenny enjoys coaching youth swimming, rereading Harry Potter, Sara Hall: 6 Tips on Coping With a Stubborn Injury.
