A Rant on Straight Leg Raises (SLR)

The good ol’ straight leg raise (SLR) – how and why this became a staple of any lower extremity injury/pain/surgery is still a mystery to me. More importantly, with all the advances in our profession, why are clinicians still using the SLR with their patients!? I think the SLR as an exercise should be retired from the physical therapy world.

Unfortunately, the SLR seems to have developed such a strong foothold in the rehab world. I have had a handful of students over the years and when I ask them how they plan on improving a patient’s quad activation, the first thing they typically say is SLRs and quad sets and I just hang my head and sigh. The other day, I had an orthopedic surgeon tell one of my patients that I wasn’t doing the right things and that in order to get his quad stronger he should do quad sets and SLRs….again, shook my head and sighed. If you ask someone who had PT for a lower body injury, I bet many of them will describe the SLR as an exercise they did….and I cringe.

To be clear, I have no problem using a SLR for diagnostic purposes, but definitely have issues with it being used for “knee strengthening.” Diagnostically, for a post-op knee patient, I use it to get a gross idea of quadriceps muscle activation and, for a lumbar/lower quarter patient, I look at it as a movement pattern.

I specifically said quad muscle activation and not strength, because even if a patient has a good superior patella glide and no quad lag, it doesn’t mean they aren’t “weak” or conversely, that they are “strong”. Case in point, I had a patient a couple weeks s/p ACL reconstruction who had a normal SLR and when I tested their quad MVIC, their quad index was 40% (60% strength deficit). This also happens to be one of the reasons why I can’t stand it when surgeons use the SLR as a criteria for doing certain things.

So onto why I think the SLR as an exercise should be banished from the PT world.

Most clinicians who use SLRs will probably say that they are using it to improve quad strength (what “strength” really means is a debate that could go on for quite some time, so I won’t get into that). I just want to say that if you think a SLR is really going to improve someone’s strength, then you clearly have never worked out a day in your life – if you have, then you should probably take a bunch of continuing education courses before you treat any more patients (and, unfortunately, you’re also probably not reading this blog). And if you think SLRs are an effective way to strengthen the quad, then why do you rarely load it up with weight and when you actually do, I bet you don’t use more than a 5 lbs. ankle weight.

Or better yet, you should throw a 5 lbs. ankle weight on, do a few sets of SLRs and tell me where you feel it – I bet it will be in your groin. That’s because when used as a quad “strengthening” exercise, the muscles you are really working are your hip flexors. And I don’t think you want to irritate a patient’s hip flexors because that’s something that is really tough to calm down.

To the clinicians who say they use SLRs to improve quad activation, I want you to take a minute, go back to PT school and think about how the muscle length-tension relationship works. If a patient has a difficult time activating their quad and you want to give them the best chance to activate it, why would you put the quad muscle in the shortest possible position (full knee extension)!? So the SLR puts your quad in a one of the most mechanically disadvantageous position to contract (and then actually makes the rectus femoris even shorter as you do the exercise).

The next time you have a patient who presents with a quad lag with SLR, try this: have them do 10 SLRs, re-test SLR, and watch how they still have a quad lag; then have them do 10 knee extensions sitting on the edge of the table, re-test SLR, and I bet it will have more of an effect than repeated SLRs. The method that is probably the most effective would be to use NMES to the quad.

And don’t even get me started on clinicians who use the SLR x 4 (flexion, extension, abduction, adduction) with the same ankle weight strapped on – this screams LAZY & OLD-SCHOOL to me.

So why are we, as movement and exercise experts, using an ineffective exercise when there are so many other options out there? Not only can we elevate our profession by improving our skills/knowledge, but also by eliminating the bullshit physical therapy that unfortunately is far too common.

I can't be the only one who thinks this way (at least I hope not), so please add your thoughts!

- Dennis Treubig, Modern Sports PT

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Interested in live cases where I apply this approach and integrate it with pain science, manual therapy, repeated motions, IASTM, with emphasis on patient education? Check out Modern Manual Therapy!

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