Range of motion

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Range of motion (ROM) is how far a moving part can travel. In the body, ROM is the angular distance a joint can move from bending to straight. People work to improve ROM with ROM therapy, which uses stretching and other exercises. In engineering, ROM is the range of travel for a device, like a volume knob.

Each joint has a normal ROM expressed in degrees. Normal ROM varies a bit by age and sex, and it can decrease slightly with age. Tools like a goniometer or inclinometer measure ROM by aligning a stationary arm, a fulcrum, and a movement arm to read the angle. Newer 3D motion capture can measure multiple joints at the same time to assess active ROM.

Limited ROM means a joint can’t move as well as normal. It can come from problems with the joint, injuries, or diseases such as osteoarthritis or rheumatoid arthritis. Pain, swelling, and stiffness from arthritis can limit ROM and make daily activities harder. Limited ROM can affect either extension or flexion; if extension is limited, it’s called a flexion contracture or flexion deformity, and if flexion is limited, it’s simply limited flexion.

Physical and occupational therapy can help improve joint function by focusing on ROM exercises. The goal is to gently increase ROM while reducing pain, swelling, and stiffness. There are three types of range of motion exercises.