Which type of prosthetic foot is noted for its rigidity and lack of energy efficiency?

The choice of single-axis feet is attributed to their design, which emphasizes rigid construction to provide stability and control during movement. This type of prosthetic foot has a simple hinge mechanism that allows for up-and-down motion at the ankle, which can effectively absorb shock but does not permit much horizontal or rotational movement. Due to this rigidity, single-axis feet often lack energy efficiency, making them less suitable for active or varied environments where flexibility and adaptability are required.

In contrast, dynamic response feet incorporate materials that provide energy return, enabling a more natural gait and better propulsion during walking or running. SACH feet utilize foam cushioning to create a balance between stability and flexibility, enhancing comfort and efficiency. Multiaxial feet allow for motion in multiple directions and provide better ground compliance, catering to varied terrain while offering a more energetic response. Thus, the limitation of energy efficiency in single-axis feet is mainly due to their focus on stability and rigidity rather than energy optimization.