Range of motion

Range of motion (or ROM), is the distance (linear or angular) that a movable object may normally travel while properly attached to another object.

As used in the biomedical and weightlifting communities, range of motion refers to the distance and direction a joint can move between the flexed position and the extended position. The act of attempting to increase this distance through therapeutic exercises (range of motion therapy—stretching from flexion to extension for physiological gain) is also sometimes called range of motion.

Measuring range of motion
Each specific joint has a normal range of motion that is expressed in degrees.

Devices to measure range of motion in the joints of the body include the goniometer and inclinometer which use a stationary arm, protractor, fulcrum, and movement arm to measure angle from axis of the joint.

As measurement results will vary by the degree of resistance, two levels of range of motion results are recorded in most cases.

Limited range of motion
Limited range of motion refers to a joint that has a reduction in its ability to move. The reduced motion may be a mechanical problem with the specific joint or it may be caused by injury or diseases such as osteoarthritis, rheumatoid arthritis, or other types of arthritis. Pain, swelling, and stiffness associated with arthritis can limit the range of motion of a particular joint and impair function and the ability to perform usual daily activities.

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


 * Passive range of motion (or PROM) - Therapist or equipment moves the joint through the range of motion with no effort from the patient.
 * Active assistive range of motion (or AAROM) - Patient uses the muscles surrounding the joint to perform the exercise but requires some help from the therapist or equipment (such as a strap).
 * Active range of motion (or AROM) - Patient performs the exercise to move the joint without any assistance to the muscles surrounding the joint.