AlterG or LEVER? How to Choose for Your Injury Comeback

November 11, 2026

Short answer: An anti-gravity treadmill (like the AlterG) uses air pressure in a sealed chamber to take up to 80% of your body weight off. It costs tens of thousands of dollars, so most runners use one at a PT clinic. LEVER is a harness and frame that attaches to a treadmill you already own and takes up to 45 lb off your body weight, so you can use it at home as often as you need.

Both do the same basic job: they let you run with less of your body weight, so each step puts less load on whatever is healing. Where they differ is how much weight they can take off, how exact the setting is, what they cost and where you can use them. Here's the honest breakdown.

Runner training with LEVER on a home treadmill

ANTI-GRAVITY TREADMILLUp to 80%Of your body weight offDown to 20% of your body weight, set by percentage

ANTI-GRAVITY TREADMILL$35,000+To buy oneMost runners use one at a clinic or university

LEVERUp to 45 lbOff your body weightOn the treadmill you already own

LEVER2 minTo set up10 lb aluminum frame that packs into a bag

How does an anti-gravity treadmill work?

Short answer: You zip into a pair of shorts that seal into an air chamber around your lower body. The machine raises the air pressure inside, which lifts you and takes part of your body weight off.

You pick the setting as a percentage of your body weight, from 100% down to as low as 20%, with the push of a button. The technology comes from NASA research on differential air pressure. AlterG is the best-known brand and the one most clinics use.

How does LEVER work?

Short answer: You wear LEVER shorts that connect to a lightweight frame around your treadmill. Bungee cords on each side lift up on your hips and take up to 45 lb off your body weight.

The frame is four aluminum pieces, weighs about 10 lb and sets up in around 2 minutes on most home treadmills. You set the amount of support by adjusting the bungees, with markers that help you estimate how much weight you're taking off. Scale versions add the LEVER Precision Scale and app so you can track it more exactly.

Anti-gravity treadmill vs LEVER: side by side

ANTI-GRAVITY TREADMILLLEVER

How it lifts youAir pressure in a sealed chamber around your lower bodyHarness shorts and bungee cords on a frame

Weight offUp to 80% (down to 20% of body weight)Up to 45 lb

How exactSet an exact percentage with a buttonEstimated with bungee markers. Scale versions track it more closely

Where you use itMostly PT clinics, university and team facilitiesAt home, on the treadmill you already own

CostRoughly $35,000 to $75,000 to buy. Clinic sessions are often part of a PT visitAround $1,000 to $1,250 depending on the setup

Space and powerAbout 7 ft long and needs its own 220V outletSmall frame, no power, packs into a bag

Best forEarly rehab that needs a lot of weight off, with a clinicianRegular runs for weeks or months, at home

Anti-gravity specs from AlterG's published FAQ and independent reviews. Prices change, so check current pricing.

Is 45 lb enough?

Short answer: For a lot of runners, yes. For runners between about 130 and 210 lb, 45 lb is roughly 20 to 35% of body weight. That covers easy runs and most of the middle and later stages of a comeback.

YOU WEIGH45 LB OFF IS ABOUT

130 lb35% of your weight

150 lb30% of your weight

170 lb26% of your weight

190 lb24% of your weight

210 lb21% of your weight

Where an anti-gravity treadmill pulls ahead is the very early stage. If your physio wants you running at 50% of your body weight or less, say right after surgery or early in a bone stress injury, you'll need the air chamber for that part.

Which one should you choose?

Anti-gravity treadmillGo anti-gravity if...• Your plan calls for more than about a third of your body weight off• Your physio wants an exact percentage for a strict protocol• You have easy access through a clinic and only need a few sessions

LEVERGo LEVER if...• You need to run with support a few times a week for weeks or months• Your plan sits in the 10 to 35% range• You want to use it beyond injury, for easy runs in big training weeks• You already have a treadmill at home

You can also do both. Start on an anti-gravity treadmill at the clinic while you need a lot of weight off, then keep going at home on LEVER once you're in LEVER's range.

What does the research say?

Short answer: Running with part of your body weight taken off lowers the forces on your body. Most of that research was done on anti-gravity treadmills, and one study looked at a harness system like LEVER.

What the research showsLess weight, less force, a slightly different strideStudies on body-weight-support treadmills show ground reaction forces drop as support goes up (Grabowski and Kram 2008; Vincent et al. 2022).A 2025 study of 26 competitive runners on an anti-gravity treadmill found that runners take fewer, longer steps with support. Keep your cadence close to normal either way.A 2023 study on a harness-style support system found about 9.5% less Achilles tendon load and 9% less impact than running at full body weight (Pohlman et al. 2023).

Be honestNeither one heals tissue fasterThere's no trial showing either type speeds up bone or tendon healing. They let you run sooner at a safer load.

Good to knowLEVER isn't in those trialsMost studies use anti-gravity treadmills. LEVER works on the same idea, but LEVER itself hasn't been tested in those trials.

NO CLINIC NEEDED Run with less body weight at home. LEVER attaches to the treadmill you already own and takes up to 45 lb off your body weight. Shop LEVER →

Quick answers

Is LEVER an anti-gravity treadmill?

No. An anti-gravity treadmill uses air pressure in a sealed chamber. LEVER is a harness and frame that attaches to a regular treadmill and uses bungee cords to take up to 45 lb off your body weight. Both let you run with less of your weight.

How much does an AlterG cost?

Published estimates put an AlterG anti-gravity treadmill at roughly $35,000 to $75,000, which is why most are in PT clinics, universities and team facilities.

Can I get an anti-gravity treadmill at home?

It's possible, but most runners don't. Besides the price, AlterG's own specs call for a dedicated 220V outlet and about 7 ft of floor length. LEVER was built to give you body weight support at home instead.

How much weight does LEVER take off?

Up to 45 lb. For a 150 lb runner that's about 30% of their body weight.

Will LEVER work on my treadmill?

It's built to fit most home treadmills, including brands like NordicTrack, Peloton, Sole and ProForm. Check LEVER's compatibility list for your model.

Which is better for a stress fracture?

It depends on the stage. Early on, if your physio wants more than about a third of your weight off, an anti-gravity treadmill can go lower. Once you're in the 10 to 35% range, LEVER lets you keep running at home as often as your plan calls for. Read our stress fracture guide.

General information, not medical advice. Work with your doctor or physio on your own return-to-run plan. AlterG is a trademark of AlterG, Inc. and is not affiliated with LEVER.

References

1. Grabowski AM, Kram R. Effects of velocity and weight support on ground reaction forces and metabolic power during running. J Appl Biomech. 2008;24(3):288-297.

2. Vincent HK, Madsen A, Vincent KR. Role of antigravity training in rehabilitation and return to sport after running injuries. Arthrosc Sports Med Rehabil. 2022;4(1):e141-e149. doi:10.1016/j.asmr.2021.09.031

3. Fohrmann D, Winter I, Simon A, et al. Biomechanical changes during running on a lower body positive pressure treadmill in competitive runners. Scand J Med Sci Sports. 2025;35:e70063. doi:10.1111/sms.70063

4. Pohlman C, Pardee A, Friedman M, Rutherford AD, Vannatta CN, Kernozek TW. Effects of body weight support in running on Achilles tendon loading. Int J Sports Med. 2023;44(12):913-918. doi:10.1055/a-2113-1026

5. AlterG. Frequently Asked Questions (unweighting range and site requirements). alterg.com/service-faq

Last reviewed November 2026.