Recent Study Gives Insight to Quicker Recovery After A Running Injury, But Can You Afford The Treadm

Updated: Aug 13, 2018

You may have never run on an AlterG® treadmill before, or even knew what one looked like until now (pictured right), but the results of a recent study using the high-tech machine may change the way health & fitness professionals rehabilitate athletes after an injury.

Personal Experience with Running Injuries

Having had several running-related injuries myself (4 metatarsal stress fractures & 1 ankle break), I know what it is like to have to put your training on hold while recovering. After each of my injuries, I was treated with immobilization and a walking boot. Running was not allowed for several weeks, so I hit the pool, used the elliptical when I could, and/or weight-trained. Had I known about the AlterG® (and had access to one), my rehab back to racing could have possibly been accelerated.

AlterG® Treadmill

The AlterG®, developed in 2005, is a reduced gravity treadmill that uses positive air pressure to control the amount of body weight (BW) forces being applied (between 20% and 100%) (6). Professional athletes (e.g. Kobe Bryant, Kara Goucher) and sports teams (e.g. New England Patriots, Boston Red Sox), along with multiple US Olympic training centers, have used the treadmill (2). Its success in rehabilitating elite athletes likely contributed to the company’s success and its presence in 1000 facilities within the first 7 years of its existence (3).

Recovery After Foot Fractures

There are many factors to consider when treating fractures in the foot, including the location and severity of the fracture, the age and gender of the patient, along with the athlete’s baseline activity level and his/her end goal. In general, a typical recovery program for a central (2nd-4th) metatarsal stress fracture may consist of 4-6 weeks of immobilization, followed by a slow transition back into regular shoes with a subsequent increase in activity level until the athlete is about 2-3 months status post injury (7). At this point, the athlete could potentially be released to return to running without restrictions or limitations (6). Try presenting this timeline to an elite athlete now. Three months of no running may jeopardize their career. That’s where the AlterG® treadmill comes in.

The Study

Twenty male runners participated in a series of 36 walking & running trials using the AlterG® treadmill at different body weight percentages. The maximum forces placed along the bottom (or plantar side) of the foot (termed maximum plantar force, or Fmax) were calculated via sensor insoles placed in the participants’ shoes. This calculation was done every 2 km/hr (between 6 km/hr and16 km/hr) and at 10% body weight percentage increments (from 50% BW to 100% BW). Results are shown in Tables 1 & 2 below (taken from the study). Table 1 shows the Fmax based on the different combinations of body weight percentages at different running speeds. Table 2 shows the relative change in Fmax for both variables. As you can see from Table 1, as running speed is increased (and BW% is kept constant) there is a greater change in forces compared to when BW% was increased (while speed is kept constant) (8).

Knowing the impact of increasing running speeds on plantar foot forces may help rehab facilities when it comes to rehabilitating an athlete after an injury while using the AlterG®. For example, one may wish to initially keep the BW% and running speed lower and then, rather than increasing speed, the BW% can be increased in order to maintain lower plantar foot forces (8).

More Information & Case Studies


Costs for the anti-gravity treadmills may range from $35,000 up to $75,000; however, if you cannot afford to have one in your own home, on the AlterG® website, they offer sessions at participating locations (1,5).

Case Studies

The AlterG® website contains a list of several case studies of athletes that used the AlterG® treadmill to help them continue training even while injured. Click here ( to read about a long distance runner who started training on the AlterG® treadmill right after being diagnosed with a 3rd metatarsal stress reaction (4).

Disclaimer: This blog is meant for educational purposes only and should not be construed as medical advice. Always consult with a healthcare professional before starting any strenuous activities and, if you are currently suffering from an injury, your recovery should be overseen by a healthcare and/or fitness professional. The doctor is not a paid consultant of AlterG®.


1. AlterG® Anti-Gravity Treadmill® (2017). Retrieved from

2. AlterG® Anti-Gravity Treadmill® (2017). Retrieved from

3. AlterG® Anti-Gravity Treadmill® (2017). Retrieved from

4. AlterG® Anti-Gravity Treadmill® (2017). Retrieved from

5. Brooks, A. AlterG Anti-Gravity Treadmill – Speed work, rehab and more. Retrieved from

6. Jamieson, M., Everson, S., Siegel, C., & Miller, T. L. (2016). Expected Time to Return to Athletic Participation Following Stress Fracture in Division I Collegiate Athletes. Orthopaedic Journal of Sports Medicine, 4(7 suppl4), 2325967116S00186.

7. Tenforde, A. S., Kraus, E., & Fredericson, M. (2016). Bone stress injuries in runners. Physical medicine and rehabilitation clinics of North America, 27(1), 139-149.

8. Thomson, A., Einarsson, E., Witvrouw, E., & Whiteley, R. (2017). Running speed increases plantar load more than per cent body weight on an AlterG® treadmill. Journal of sports sciences, 35(3), 277-282.

#altergtreadmill #kobebryant #karagoucher #runninginjury #sportsinjury #recovery #treadmillrunning #rehabilitation #antigravitytreadmill

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