Why You Need To Use The Limb Symmetry Index

assessment Feb 14, 2018

The Limb Symmetry Index (LSI)  is an excellent guide to objectively determine discrepancies in your patient’s upper and/or lower limb strength, function, and mobility.

The LSI is calculated by taking the average of any test scores for the affected limb, divided by the unaffected limb, multiplied by 100 to obtain a percentage difference between limbs.

Clinically, it is an easy-to-use, quick measure that can provide valuable data for baseline and progression purposes. It has been shown to be of significant importance in deciding when an athlete is ready to return to sport after anterior cruciate ligament (ACL) injury, with percentage values for knee extension and flexion strength equal to or above 90% considered to be satisfactory (Abrams et al., 2014).

Recent studies have also shown that:

  • At 1 year post-ACL injury, those with normal knee function had LSI values greater than 90% for the single-leg, cross-over, and triple hop tests - the LSI hop testing battery (Wipfler et al., 2011)
  • An LSI score of less than 15% is recommended in a drop vertical jump landing force for all athletes, regardless of sport, prior to return to play (Myer, Paterno, Ford, Quatman, & Hewett, 2006)
  • The LSI be used in conjunction with a range of other tests and criteria for appropriate decision-making regarding return to play, including reference to healthy, normative values if data is available for reducing the risk of injury and re-injury (Abrams et al., 2014)

Would you like to learn more about the LSI?

Check out our MAT Live and MAT Online courses at: 

You can try ur FREE Online Course module here:  at 

Stay connected with the latest MAT news and updates!

Join our mailing list to receive the latest news, research and updates from the MAT team.
Don't worry, your information will not be shared.

We hate SPAM. We will never sell your information, for any reason.