Running is an advanced skill that requires a well healed residual limb, good bone density, and a comfortable fitting definitive socket. The only difference between running gait vs. walking gait is a period of time where both feet are airborne. It is easier and safer to run on a prosthetic foot designed specifically for running, but is possible to run for short spurts on a walking foot. Running feet are different than walking feet in several ways: they typically do not have a heel; they typically have tread secured to the carbon fiber and do not require a shoe; and they are set up taller than a walking foot due to the amount of compression. Current running feet have either a C-shape or J-shape. Sometimes, the same socket can be used and only the feet are interchanged using a quick disconnect adapter or with an Allen wrench if properly instructed by your prosthetist. The J-shaped running feet require a separate socket for below the knee prostheses. Those feet that do include a heel are designed as more of a hybrid sports foot that compromises walk/run benefits. For longer distance and faster running, doing so on a running foot is essential in order to reduce abrupt impact through the prosthesis which affects the residual limb, knee, hip, and back. Also, due to the extra compression, the effectively short prosthesis can throw off the hip and back. Despite this evidence of risk by running on a foot designed for walking, it can be difficult with some insurance policies to gain approval. As an alternative, feet can be purchased out of pocket or you might apply for a grant. Please contact us for a list of charities that offer grants for running feet.
Safety and training
When running for the first time after an amputation, it’s recommended that you first get a bone density test, since often times after amputation the residual limb bone is more prone to fracture. It’s also ideal to have your physical therapist and/or prosthetist present for your first run in order to offer training tips and make alignment adjustments. Wrist guards may be a good idea in case of a fall. This is a good resource for tips starting out: http://www.amputee-coalition.org/military-instep/introducing-running-lower-limb.html
Running with a below the knee prosthesis
Because most running feet do not have a heel, it’s important to stabilize your knee in order to prevent hyperextension. Landing with the knee slightly flexed will help you get the hang of this at first. Holding onto a bar or counter, you can start to jump up and down to get the feel of the bounce in the foot. Next, try jumping onto the prosthesis and then walking. Once you start getting comfortable with that, you can pick up the tempo and will be able to jump off of the prosthesis onto the sound limb. At that point, continue on, and you’ll be running. You should stop immediately if you start to experience pain or if your socket is spinning or losing suspension. Running legs with J-shaped feet are available for amputations at the ankle and for rotationplasty.
Running with an above knee prosthesis
The use of a waist belt as an auxiliary (secondary) suspension is a good idea to ensure rotation control and positive suspension. With an above knee amputation, you can use a running foot with a straight pylon (no knee) or a running foot with a knee joint. Advantages of no knee are that it is lighter weight and there is no risk of the knee buckling, making it safer on uneven ground or when going downhill. Advantages of using a knee are that it is more efficient during swing through and provides greater gate symmetry. The biomechanics are slightly different between these two options. When a straight pylon is being used, the foot must swing out to the side (circumduction) in order to clear the ground. With a knee, the prosthesis can stay straight when swinging forward. The motion required using either option is the use of powerful hip extension once the foot is in contact with the ground. Starting out is similar to the steps mentioned above for individuals with below the knee amputations.
Running with a hip disarticulation prosthesis
It takes a very motivated and fit individual to run with this amputation level. The prosthesis also has to be fitted and aligned well. It is difficult enough to walk using this level of prosthesis, so quite incredible when we see someone run. Recently, a young veteran with a hip disarticulation amputation level completed a marathon running on a straight pylon with no knee and no hip joint! It is also possible to run with hip and knee unit. This method does require a bit more caution since the knee could buckle. It is recommended that you work very closely with your prosthesis and/or physical therapist if you want to run with this amputation level.
Running with bilateral leg prostheses
For bilateral above knee amputation levels, my experience has been that straight pylons are more efficient and faster than using knees. However, it is possible and even preferable for some I’ve worked with to use knees. Above knee/below knee combinations often do better with the use of a knee joint, but this is not universal. Bilateral below knee running is very popular in the media with Paralympic athletes crossing into the Olympic competitions. The debate of mechanical advantage still comes up both in the Paralympic discussions as well as Olympic. One thing is for certain, and that is that athletes with bilateral amputations have the advantage of maximizing their overall height within the boundaries of the Paralympic rules, which increases stride length and speed, especially with longer distance sprints.