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What Is Range of Motion (ROM)?


Updated May 15, 2014

Definition: Range of motion (ROM) is a term commonly used to refer to the movement of a joint from full flexion to full extension. Exercise physiologist and physical therapists measure range of motion in a joint with an instrument called a goniometer that measures joint range of motion in degrees from the starting position.

Extension is a physical position that decreases the angle between the bones of the limb at a joint. It occurs when muscles contract and bones move the joint into a bent position. The opposite movement, flexion, bends the joint so that the joint angle shortens.

Each joint has a normal range of motion. However, the amount of movement in a joint varies greatly between individuals. Joints maintain a balanced range of motion by regular use and stretching of the surrounding soft tissues (muscles, tendons and ligaments).

Injuries to the soft tissues surrounding a joint often reduce range of motion due to swelling and tissue damage. Regaining range of motion in a joint is one of the first phases of injury rehabilitation, and physical therapists often prescribe specific ROM exercises for each joint.


Physical Therapy (PT). Merck Manual Professional. November 2005. [www.merck.com/mmpe/sec22/ch336/ch336b.html]

Also Known As: ROM, joint movement, full flexion and full extension
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