Prosthetic components will replace a lost limb and restore function to the individual. From a carved wooden leg to a new composite materials , prostheses become stronger, lighter and more functional. Appropriate prosthetic design and rehabilitation training can increase amputees activities. Prosthetists should pay attention on the choices of prosthetic components to meet patients requirements. For example, the application of carbon fiber composite materials to prosthetic feet allow amputee to run, hiking and dancing. A J-shaped carbon spring design allows the spring to compress causing energy storage when it is loaded with the amputee weight and to return that energy as the spring is unloaded.
