Range of Motion

Extended Definition

Range of motion (ROM) refers to the extent of movement around a joint, typically measured in degrees. For example, a healthy knee can usually bend (flex) to about 130-140 degrees and straighten (extend) to 0 degrees or slightly beyond. Healthcare providers assess range of motion to evaluate joint health and function.

There are three types of range of motion: passive ROM (when someone else moves your joint for you), active ROM (when you move the joint yourself using your own muscles), and active-assisted ROM (when you move the joint with some help). Measuring these different types helps providers understand whether limitations are due to joint problems, muscle weakness, pain, or a combination of factors.

In osteoarthritis, range of motion often becomes progressively limited as the disease advances. This happens for several reasons: joint inflammation and swelling, formation of bone spurs that physically block movement, stiffening of the joint capsule and surrounding tissues, muscle tightness or weakness, and pain that causes people to avoid moving the joint fully. Maintaining and improving range of motion is a key goal of treatment. Physical therapy exercises, gentle stretching, and pain management strategies can help preserve joint mobility and prevent further stiffness. Early intervention is important because once soft tissues contract and adapt to limited movement, it becomes harder to regain lost range of motion.