The knee is essentially a hinge joint but also has a limited capacity to rotate if this is imposed upon it by the orientation of your hips or ankles.

Cycling is often recommended as an ideal activity for people with knee issues as improved leg muscle strength can optimise joint stability without the compressive forces that occur in running or jumping based activities. There is however a proportion of cyclists that will develop knee pain with the most common causes being incorrect seat or cleat position, and instability or restriction of the hip and ankle joints.