What is range of motion?
Range of motion is defined as the normal degrees of motion for a particular joint. The question, in practical terms, is does the joint move the way it was designed to?
A joint like the shoulder is complex, and moves in every movement plane; the elbow is more simple: it either bends and straightens the way it is supposed to or it doesn’t.
There are two kinds of range of motion for every joint: passive and active. Passive range of motion is how far a joint moves without muscular force. The value is generally greater than active range of motion, which measures how much a joint can move without bending it using a strap, straightening with the hands, pushing against the wall, etc.
Factors limiting range of motion
Range of motion can be limited by a number of things, including:
- Swelling
- Scar tissue
- Weak muscles
- Tight tendons/ligaments
- Torn tissue (causes block in joint)
- Bony abnormality
Importance of restoring range of motion
Restoring range of motion is critical not only in the therapy process and to return to play, but to minimize the risk of future injury. If a joint is unable to move properly, secondary to tightness, swelling, or weakness in the muscles, it is exposed to increased risk of re-injury.
For example, you may have a knee injury and be lacking five degrees of extension, meaning the knee cannot fully straighten. You might think five degrees is a relatively small number, but to a therapist and doctor, it is a really big deal. A knee that does not fully straighten exposes certain parts inside the knee structure to wearing out faster and creates a relatively short leg, setting the athlete up for future injuries, not just to the knee but the hip, ankle, and back as well. In addition, that decreased range of motion will shorten an athlete’s stride while running, create imbalance from side to side, and lead to weakness in the quadriceps muscles, negatively impacting performance.