Normal Range of Motion in Back Extension and Flexion

Range of motion is the amount of movement you have with any joint before being restricted by the bones and muscles attached to the joint or by pain or stiffness. ROM differs from person to person, and the range of motion in your back for flexion and extension is unique to you. However, some general guidelines indicate what constitutes full ROM and what is considered functional ROM.


Full range of motion is described as being "within normal limits," or WNL. Normal ROM for back flexion is 90 degrees, or bending forward to touch your feet. As with most movements, this type of flexion works in tandem with other joints, including pelvic rotation, so any limitation could arise from back or pelvis issues. Normal extension ROM in your back is limited to only 25 degrees. This range is similar to moving your trunk from the 12 o'clock position when standing upright to in between the 10 o'clock and 11 o'clock position when extended.

Within Functional Limits

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Range of motion "within functional limits" -- WFL -- is a term often used by therapists and medical professionals to describe a movement for a joint that still allows you to perform any normal task, but which may be less than full range of motion. For example, back extension is rarely used in functional activities and as such only about 10 degrees of extension is usually WFL. However, back flexion is essential to many tasks, even something as simple as picking up an item you've dropped on the floor. You need around 80 degrees of back flexion to maintain functional movement.

Limitations on ROM

Range of motion can be restricted in any joint for a variety of causes. Arthritis is a common cause of stiffness; gentle range of motion and ambulation can usually relieve some of this stiffness. However, muscle tears or sprains, over-tightened muscles, bone deformities and growths and scar tissue are just some of the issues that can cause limited ROM for back flexion and extension.


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The back muscles and vertebrae are essential components of your back structure that are designed to protect your spinal cord and preserve proper nerve functioning at the location where nerves leave the spine. Any pain or limited range of motion can indicate significant health issues and should be addressed immediately, especially if you have severe pain, numbness and tingling in any body part with back movement. Continuing range of motion exercises or activities in the face of these issues can lead to further injury and complications, including paralysis, so consult your doctor or physical therapist if you have these conditions.