Making straight leg raises more knee friendly after surgery

Posted on March 7, 2016

(Last Updated On: April 6, 2016)

Here is our typical Straight Leg Raise exercise:

A common complaint after a knee surgery, like reconstructive anterior cruciate ligament (ACL), is this causes pain.

A main reason for doing this exercise is the difference between these videos.

Non-surgically repaired leg:

Surgically repaired leg:

In other words, we’re trying to get that quadricep to come back to life. The quad tends to get quiet and harder to use after a knee surgery (or injury).

The first way we can make this exercise friendlier to the knee is do only do the quad activation element:

(Again, notice the difficulty earlier, before doing the activation for a little while:


Because if it’s painful, we should not be doing it. Some discomfort is ok, but if you feel like your knee is progressively yelling at you during something like a straight leg raise, that’s not helping.

-> If your knee hurts you only doing the quad activation, you have really, really pissed off your leg. Where a serious reassessment of your current therapy needs to be had.

To understand the next modification, we need to understand what a straight leg raise is doing. When we go from the foot on the floor to the foot off the floor, the quad has to kick in, in order for the foot to not fall. The quadriceps extend / straighten the knee. In a straight leg raise, the quadriceps are isometrically holding the knee in extension.

However, the hip flexors also have to work a ton. They’re the muscles which actually get the leg off the floor!

Straight leg raise hip flexors vs quads with lines

This is one reason people’s hip gets pissed off post surgery, because they or their therapist and or doctor will harp on this unnecessary exercise.

-> By unnecessary we do not mean useless. We mean this exercise is not so important to do it regardless if you’re having hip pain, knee pain. It’s a worth working on exercise, but not at the expense of making your knee feel worse. By a couple weeks out from most knee surgeries or injuries there will be other means of strengthening the quadriceps anyways. Like leg pressing and or squatting.

What we can do instead is let the leg hang off something. Like a table or countertop.

Leg Hanging Table 1

If your leg is still locked fairly straight with the brace, doesn’t matter. You can do the same thing:

Leg Hanging Table w:BraceNext, use the good leg to help straighten the repaired leg. Then use the quad of the repaired leg to try and hold it there (squeeze the quad). If that causes pain, use the good side to help out. Keep the good side hovering nearby so it can help as needed.

This way the repaired knee isn’t having to all of a sudden hold all its weight. It can take some time for it to get that ability.

Get more help with your ACL rehab here.

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