Range of motion (ROM) is the measurement of the amount of movement around a specific joint or body part. It is commonly measured during a physical therapy evaluation or during a course of treatment. Other impairments that your physical therapist may measure include strength, gait, flexibility, or balance.
How is Range of Motion Measured?
Range of motion is measured by your physical therapist using a device called a goniometer. A goniometer is a metal or plastic handheld device with two arms. Numbers representing angular distance are on the device, much like a protractor. Your physical therapist lines up the arms along your body, and then he or she can move your body in specific directions and measure the amount of motion that occurs.
Measuring ROM is usually a painless procedure. There are some instances after surgery or injury where measuring the ROM may be painful, but the pain is usually short-lived and only occurs during the measurement.
In general, there are three types of ROM that are measured. They are passive (PROM), active-assistive (AAROM), and active (AROM).
Passive Range of Motion
Passive ROM occurs around a joint if you are not using your muscles to move. Someone else, like your physical therapist, manually moves your body while you relax. A machine may also be used to provide passive ROM. For example, after knee replacement surgery, you may not be able to use your muscles to move the knee. Your physical therapist may bend and straighten your knee for you, passively moving your leg. Occasionally, a device called continuous passive motion (CPM) is used to provide passive ROM.
Passive ROM is usually used during the initial healing phase after surgery or injury. If paralysis prevents your body from moving normally, passive ROM may also be used to prevent contractures or skin pressure ulcers.
Active-Assistive Range of Motion
Active-assistive ROM occurs when you are able to move your injured body part, but you may require some help to move to ensure further injury or damage does not occur. The assistance that helps move your body can come from you or from another person. It may also come from a mechanical device or machine.
An example of AAROM is after shoulder rotator cuff surgery. You may be allowed to move your arm, but another person may assist your arm during the motion to help limit the amount of stress that may occur. Active-assistive ROM is typically used after injury or surgery when some healing has occurred and your muscle can contract, but protection is still required to prevent damage to your healing body part.
Active Range of Motion
Active ROM occurs when you use your muscles to help move your body part. This requires no other person or device to help you move. Active ROM is used when you are able to start moving independently after injury or surgery, and little or no protection from further injury is needed. Strengthening exercises are a form of active ROM.
Be sure to speak with your physical therapist or doctor to understand what type of ROM is necessary if you are injured or have had surgery.
Understanding what range of motion is and how it is used in physical therapy can help you become better informed about your course of physical therapy and have a positive physical therapy experience. Working towards normal ROM can help ensure a safe and rapid return to optimum functional mobility.