What Is Range of Motion (ROM) and Why Is It Important?

The Definition of Range of Motion, or ROM

What is range of motion?
What is range of motion?. Patrik Giardino/Getty Images

Range of motion, or ROM, is a term commonly used to refer to the movement of a joint from full flexion to full extension. It is also known as joint movement, full flexion and 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.

What is Extension and Flexion?

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.

What Affects Range of Motion

There are numerous influences — inherit and situational — that can affect range of motion, which some may think of as flexibility. Some of the things that you can’t control and that you are born with include:

  • the type of joint; there are some joints that aren't meant to move a lot 
  • the internal resistance within a joint
  • bony structures which limit movement
  • the elasticity of muscle tissue, for instance, muscle tissue that is scarred due to a previous injury is not very elastic
  • the muscle's ability to relax and contract to achieve the greatest range of movement

Another factor that you can't control: How old you are. One study examined the effects of age and sex on joint ranges of motion and found that older participants showed smaller ROMs than their younger counterparts.

In one case, the difference in ROM was 44.9 percent and that was for the eversion and inversion of the foot. What’s more: older subjects needed more time to reach full range of motion.

As for gender, it was found to have a significant effect on range of motion. Men had smaller ROMs than women in some areas, with the greatest differentiation, 29.7 percent, occurring in the hand.

These differences in age and sex were found to effect specific joints and motions, which could be explained by the differences in anatomy and the frequency that the joints are used in activities between the groups. 

Then there are some things that you can do that can affect your range of motion. 

What Increases Range of Motion

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). Just 10 minutes of stretching three times a week can help improve range of motion.

Applying heat while stretching may also increase the range of motion to your stretches, suggests a 2012 scientific review in the journal, Physical Therapy in Sport. Though the gains are not huge ones. In healthy individuals, those who were complaining of tight muscles saw a slight improvement in range of motion compared to those who only stretched.

What Limits Range of Motion

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.

Sources:

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

Behm DG, Blazevich AJ, Kay AD, McHugh M. Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Appl Physiol Nutr Metab. 2016 Jan;41(1):1-11. doi: 10.1139/apnm-2015-0235. Epub 2015 Dec 8.

Hwang J, Jung MC. Age and sex differences in ranges of motion and motion patterns.Int J Occup Saf Ergon. 2015;21(2):173-86. doi: 10.1080/10803548.2015.1029301.

Nakano J, Yamabayashi C, Scott A, Reid WD.The effect of heat applied with stretch to increase range of motion: a systematic review.Phys Ther Sport. 2012 Aug;13(3):180-8. doi: 10.1016/j.ptsp.2011.11.003. Epub 2011 Dec 29.

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