- Discussion:
    - excessive heel softness: causes knee hyper-extension;
    - excessive heel stiffness: knee tends to hyper-flex at heel strike;

- Types of Prosthetic Feet:
    - SACH foot:
    - single axis foot:
          - used since the Civil War, is based on an ankle hinge that provides dorsiflexion and plantar flexion;
          - disadvantage of single axis foot includes poor durability & cosmesis;
    - multaxis foot:
          - allows inversion and eversion and rotation of foot and are good for work on uneven surfaces
                  at the expense of overall utility and wt;
    - energy storing:
          - designed with a flexible keel and may perhaps become the new standard for general use;
          - these are designed with a cantilever spring and are best for youngg & atheletic patients