ROM is an abbreviation of 'range of motion'.

Page updated January 2024 by Dr Sheila Strover (Clinical Editor)

range of motion

Normal ROM.

plastic goniometer for measuring range of motion

Plastic goniometer for measuring ROM.


Normal range of motion in the knee

Normal ROM in the knee is usually minus 5 to 143 degrees in women and minus 6 to 140 degrees in men.

Flexion is that motion that moves the heel closer to the buttock. Extension is that motion that moves the heel closer to the position where the knee is straight. Hyperextension can be normal or as the result of an injury, and is that motion that moves the knee from fully straight to arching a bit backwards.

Back to top


Factors affecting normal knee range of motion

Normal range of movement is not the same in everyone. It can depend upon:

  • gender - men tend to have a greater ROM than women
  • body fat - fat behind the knee can limit flexion
  • ligament mobility - some people have greater ligamentous flexibility
  • fitness

Back to top


What factors limit range of motion in the knee?

Range of motion in the knee can be limited by -

  • muscle weakness
  • pain
  • reflex muscle inhibition
  • fluid in the knee (effusion)
  • damage to joint structures from injury, eg fractures, ligament damage
  • a true mechanical block (eg cyclops lesion, adhesions or scar tissue in the normally-mobile soft tissue areas around the knee)

Back to top


Forum discussions

Back to top


Range of motion

Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...