The biggest fear that many of my patients have after tearing their ACLs is that they may not be able to go back and play sports at the same level that they used to.  Some even fear not being able to play at all.  The same question could be made for those who have torn their ACLs and don’t want surgery but still want to be active. Either way, you should be able to pass all of these tests below.

Before returning to any sport that may involve full sprints, jumping, and/or cutting, in addition to moving smoothly and painfree (your coach, teammates, workout partners, trainers, and physical therapist can help with this), rehab specialists generally require you to have 90% of your full strength and function.  Of course, before doing these tests on your own, I would expect your form for the basic strengthening exercises to be perfect (squats, deadlifts, lunges, etc)

To test for strength: 

Single leg squat: standing on your non-surgical leg, squat as low as you can and tap your heel of your other leg as far in front of you. Then stand up. That’s 1 rep. Attempt to repeat this for as many reps as you can.


Then try on your surgical leg. You should be able to squat and reach just as far. Then repeat.  You should be able to do 90% or more of your other leg (for every 10 that you did on your non-surgical leg, you should be able to do 9 on your surgical leg).

This is just one exercise. In the clinic, I would also test or bias other muscles in your leg, which should all be 90% as strong or stronger as your non-surgical leg.  Also try: lunges for max weight, single leg deadlifts.

To test for function:

Generally, the tests that are most often used are the HOP TESTS (they’re easy to measure).  Again, this is with the assumption that you’re hopping well and with good form (knee doesn’t collapse inwards, adequate foot/ankle and trunk stability, etc). If you’re not sure, again, check with a properly skilled trainer or therapist.


Single leg hop: Stand on your non-surgical leg, and then hop as far as you can and stick the landing.  It won’t count otherwise.  Measure the distance.

Then do the same thing on the surgical leg.  Your best jump from each should be within 90% of each other.

Triple hop: same as above, this time you hop off the same leg 3 times consecutively, but you don’t have to stick the landing.  Again, measure your best distance, and then do so on the surgical leg.

Crossover hop: same as above, but this time you will hop over a line sideways as you hop forward. With each hop you should cross the line.

Timed 6 meter hop: This is a hopping test for speed.  Measure out 6 meters.  Start at one end, and start the timer as soon as you hop. Get to the other side as fast as you can on one leg.  Repeat on the other side.

I feel I am ready to go back and plays sports. Why do I need to do these tests?

The main reason physical therapists and trainers use these tests is 2-fold: 1) they are objective and demonstrate clear strength and functional marks that can be measured and 2) They are repeatable, measurable, and easy to study.  There are different surveys including the Lower Extremity Functional Scale (LEFS) and the International Knee Documentation Committee Survey (IKDC) that can demonstrate when one isn’t ready to return to sport. Meaning, if you take these tests and score low, you’re most likely not ready.  However, if you score high, there’s still a pretty good chance (about 50%!) that you still aren’t ready, and that’s when it’s helpful to have these strength and functional tests.


“Return to Sport: When to Resume Full Activity After an ACL Surgery.” Perspectives for Patients, Journal of Orthopaedic & Sports Physical Therapy, 2014. 44(12): p924. doi:10.2519/jospt.2014.0507

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