- The primary function of the knee is to flex and extend the lower leg relative to the thigh.
- The range of motion is determined by each person’s particular bones and ligaments. For averages, see Joint Movements.
- Knee joint movement is essential to such everyday activities as walking, running, sitting and standing.
- Unlike other hinge joints, the knee also allows some rotation when flexed.
Strength & Adaptation
The knee… must be strong, because a great amount of our body weight passes through it… It must also be flexible enough to deal with the adaptations of the ankle and foot, which change shape and position… [and] it must adapt to the hip and its role as we walk. When the balance between these joints and their roles (strength and flexibility) goes awry, the knee often receives the forces. – David Keil