What are the types of materials used in prosthetic legs, and how do they aid the strength of the prosthetic leg?

Question: What are the types of materials used in prosthetic legs, and how do they aid the strength of the prosthetic leg?
- Keywords:
  material,
  prosthetic leg
Asked by olhall27 to Ana on 14 Mar 2017.
- Ana Gallego answered on 14 Mar 2017:
  
  All sorts of materials. The main principle is that the artificial leg is no more heavy than the sound (healthy, intact) leg. If it is heavy, you can start having problems in your back, hips or in the intact knee.
  This means that with a combination of materials, we have to achieve good strength and durability with minimum weigh.
  So the main materials are aluminium, (minimum) stainless steel, titanium, carbon fibre (great material, great properties), rubbers and foam.

Question: What are the types of materials used in prosthetic legs, and how do they aid the strength of the prosthetic leg?