Carbon fiber running feet are the ideal choice for running prostheses. This type of foot is compressed by body weight and returns to its original shape as you push off of it. The result of this compression and decompression of the blade is that energy is released as you push off allowing you to run more efficiently by minimizing the amount of energy you need to expend.
basics of a carbon fiber prosthesis
- Running specific prostheses often mimic a "running on toes" running form.
- The stiffness of the blade is dependent on the runner's body weight.
- Using a carbon fiber prosthesis has been shown to decrease heart rate and energy cost with running compared to running in a prosthesis designed for walking.
- The blades can either be C or J shaped depending on the type of running you wish to participate in and they can also vary on whether they are attached directly to the socket or below the socket.
- Sprinting feet generally attach to the socket whereas jogging feet generally attach below the socket.
"C" Shaped feet
- "C" shaped blades are more commonly used for a jogging pace and distance running.
- This shape is more effective at storing and releasing energy over time which helps you to run more efficiently and for longer periods of time.
- Pictured to the left is the Flex-Run offered by Össur.
"J" Shaped feet
- "J" shaped blades are more commonly used by sprinters.
- This shape allows for a quick return of energy helping you to achieve higher speeds.
- It is more difficult to learn to run on a sprinting specific foot than a jogging foot. This is because you need to put more into this foot in order to get the most out of it and starting off, one may not have the necessary strength to make this kind of foot energy efficient.
- Some J shaped blades include the 1E90 Sprinter by Ottobock and the Cheetah Xtend, Xplore, and Xtreme by Össur.
- For individuals with above knee amputations there are two options:
- A straight pylon
- This component results in the use of compensations such as circumduction (swinging the leg around to the side) in order to take a step forward and can result in injuries in the long term.
- A knee component
- A knee component will allow for a more natural swing phase of gait and can create a more symmetrical running form.
- The key aspect of a running knee is a low level of resistance, or friction, which will allow you to quickly swing the leg through to keep up with the fast speed of running.
- The only fitness specific knee on the market currently is the Ottobock 3S80 Sport Knee Joint. However, many knees are suitable for running as long as the level of resistance can be lowered to an amount suitable for the sport so talk to your prosthetist about what will work best for you.
- A straight pylon
- The optimal method of suspension for running is a suction socket as it provides the closest fit for the residual limb, ensuring little movement in the socket. In addition a suction provides increased proprioception, or sense of position, in the socket which can result in better performance.
- For some, suction is not an option or it is not their preferred method of suspension. In this case a custom liner or a pin-locking system are some of the other possibilities.
- Talk with your prosthetist about which type of suspension will work best for you.