Supple Leopards VS. The World:
My Take On The “Knees Out” Debate
Quinn Henoch, PT, DPT
Recently, on Bob Takano’s blog, there was an in-depth series of discussions regarding the use of the extreme “knees out” technique when performing the squat. For those of you not familiar with Bob Takano, he is a USA Weightlifting Hall of Fame inductee who has coached numerous champions at the national and international level.
The debates were sparked when a chiropractor and former USAW Sports Med Chair, Dr. Brendan Murray, emailed Takano about the reasoning behind why athletes (crossfitters specifically) were shoving their knees out forcefully outside of the foot and ankle during squatting and pulling movements. Murray was finding an increased number of injuries in his clinic, which he thought was due to this technique. This practice was quickly attributed to the teachings of Kelly Starrett, who’s side I will refer to as, “The Supple Leopard Camp”. The fun ensued shortly after, as this became a hot topic in the rehab, crossfit, and olympic weightlifting worlds. The 6-part series of debates can be found here:
To be honest, I was completely oblivious to the drama until I received a voicemail from one, Russell Berger of Crossfit HQ, asking my opinion on the subject as a PT and competitive weightlifter. It was going to be the topic on some type of Crossfit TV show or something. I then read the whole 6 part series in my car on my trusty Iphone. I encourage you all to take a look at the arguments and formulate your own opinion.
The dealings with CrossfitHQ have not panned out, as of yet; so I will have to put my TV star aspirations on hold. Regardless, I want to share my thoughts on the subject, because I am encountering many of the same issues in clinical practice.
My goal for this article is to be as objective as possible, and by no means is this meant to be some personal attack or internet jab at Kelly Starrett or his Supple Leopard camp. Starrett was a big influence in my decision to go to PT school, and his work has continued to influence my practice up to this point; though, my philosophies have evolved greatly over the past 3 years. Also, I do not intend this article to be an argument for whether shoving your knees out past your feet is right or wrong. I simply want to address specific statements that were made, because I believe they may contribute to the issues and misconceptions (key word) I see clinically. Here go’s…
“Knees out is not the same as driving hips into ground And we seem to solve knee problems. And back problems. In everyone. And help set American records. And world records.” –Kelly Starrett
This was Kstar’s entire contribution to the discussion. Basically, I took this to mean, ‘I’ve got a plane to catch and don’t have time for this shit’. I cannot imagine how much of this he deals with on a daily basis. So I’ll leave this one alone. But c’mon man… You solve everyone’s knee and back problems? That’s a damn good percentage. I can’t wait for that data to hit the peer reviewed literature.
From this point, the minions from the Supple Leopard Camp take over the debating responsibilities.
“Let’s establish one thing, with any movement the goal is to produce the most amount of torque and not allow any torsion [to] occur on a compression/loaded body. This directly also creates positions that get rid of every single injury we have ever seen in all our athletes/non-athletes.”
–Supple Leopard Camp
The first sentence will be addressed later. However, the proclamation that this technique, “gets rid of EVERY single injury we have EVER seen in ALL our athletes”, irritates me to the core. Again, please publish these incredible outcomes. There is no faster way to lose credibility than to say your shit works for everyone all the time, without data to back it up (I’m trying to stay objective, I promise).
Regarding The Creation Of Torque In The Hips
“Let’s establish one thing, with any movement the goal is to produce the most amount of torque and not allow any torsion [to] occur on a compression/loaded body.” -Supple Leopard Camp
“During Oly- or Power-lifting the goal again is to set yourself up to produce the most amount of torque to get the bar from point A to point B.”–Supple Leopard Camp
This idea of “torque” that the Supple Leopard Camp continued to refer to is in reference to Starrett’s book, where he frequently refers to the ‘Laws of Torque’ at the hip and shoulder.
In human biomechanics, internal torque is (Muscle Force) X (Moment Arm). The product of these two produces a force that acts on something – in this case the femur when squatting. I have not seen any evidence that suggests pushing your knees outside your feet alters internal torque in the hip in a favorable way, as it is explained in KStar’s book (which is not a peer reviewed source, nor does it contain any references). This is also a very difficult thing to quantify because below 90 degrees of hip flexion, the functions of many of the muscles that cross the hip are altered – some of the external rotators becoming internal rotators for example.1 It is fine to use these terms anecdotally, but to say the goals of weightlifting and powerlifting is to produce the most amount of torque is ambiguous at best.
Regarding Stability Of The Hip And Spine When Squatting
“If we want to speak anatomically/biomechanically/physiologically then we know that the hip is the most congruent at 90 degrees of flexion in moderate amounts of abduction and external rotation. Since Oly lifting requires more depth (Ass to Ankles) then we have to get more external rotation and abduction to maintain this congruent (minimal passive tension) to maintain the stable spine and vertical torso.” -Supple Leopard Camp
“Athletes that are squatting with toes out and knees tracking over the feet will have to find stability elsewhere (since it is not coming from the hip)”–Supple Leopard Camp
I found no evidence suggestion that “getting more” external rotation and abduction when squatting past 90 degrees maintains congruency and minimizes passive tension. In fact, by shoving your knees out maximally, you would actually increase ligamentous (passive) tension, and limit your ability to attain more hip flexion. It is shown that full hip flexion (≥120°) decreases passive tension of the capsular ligaments, and increases tension in the glute max. Full hip flexion also mechanically prepares the adductors to help with hip extension.2 So, if you are limiting hip flexion in any way, you are limiting the rubber band effect of glute max and adductors. Where I come from, the goal of a squat is to stand up, so maximally loading the muscles that help you do that is probably a good idea
I found nothing to suggest that letting your knees track over your ankles and squatting straight down creates instability in the hip or spine. The athlete should be able to continue flexing at the hip, while maintaining a neutral pelvis. If they cannot, I don’t believe the answer is to tell them to shove their knees out in order to compensate (clinical opinion).
Regarding Squat Depth
“From an anatomical standpoint, it [knees out] also un-impinges the hips allowing the femur to continue flexing without running into the pelvic bowl.” –Supple Leopard Camp
“When an athlete from the initiation and throughout until the bottom of the squat is pushing their knee out [he is referring to pushing the knee OUTSIDE of the foot] they are not actually creating a varus force, what they are doing is flexion/abducting/externally rotating the hip which allows the athlete to squat to depth.” –Supple Leopard Camp
“Also – putting your hip into max flexion/external rotation/abduction does create the most stable position but that does not mean you cannot squat ass to ankles, in fact it is the only way to squat ass to ankles while maintaining a stable/neutral spine, proper alignment in all joints and least passive tension on the body (which a loss of will cause torsion moments on the body and increased stress on joints)”
-Supple Leopard Camp
So in order to squat “to depth” and prevent hip impingement, one must maximally shove their knees out past their feet? I will refer to Colin Burn’s and Lu’s pictures above. They seem to attain proper depth without doing this.
As I mentioned before, maximal external rotation and abduction near the bottom of a squat actually increases passive tension in the hip joint by tensioning the capsular ligaments of the hip. I am not saying this is a good or bad thing. However, performing maximum range of motion in one plane will limit range of motion in another3,4. So again, shoving your knees out as hard as you can, will limit hip flexion. Maybe this is not such a bad thing for a powerlifter that only needs to squat to parallel (the pic of Dan Green below still shows his knees over ankles); but probably not so great for a weightlifter who must receive the bar in a much lower position.
I find nothing concluding that excessive external rotation and abduction is required to avoid hip impingement while squatting, or that keeping your knees over your ankles causes hip impingement, assuming no structural abnormalities. I find that if an athlete complains of hip impingement while squatting, it is usually the result of excessive anterior tilt; not because they fail to shove their knees out (clinical evidence only).
Regarding Knee And Ankle Mechanics When Squatting
“At the knee there is relative external rotation of the femur on the tibia which inherently helps stabilize the joint by placing the ACL on tension rather than a slack position.” –Supple Leopard Camp
The external rotation of the femur cited here is a subtle involuntary change that acts to unlock the knee joint so it can flex more. It does not place tension on the ACL in a squat. The ACL is almost completely slacked in the bottom of a squat. It is tensioned when the knee is straight.5,6 This one doesn’t have much significance, other than the fact that it was wrong.
“As we make our way down to the ankle we have to think beyond just dorsiflexion/plantarflexion. What we consider here is subtalar eversion that allows the foot to stay flat through relative supination at the rearfoot and pronation at the forefoot.” -Supple Leopard Camp
Considering eversion + supination is difficult for me. Supination of the foot involves heel inversion. So what I take from this – when squatting, there is relative eversion of the heel along with relative inversion of the heel. How does the body do two opposite things at the same time???
**Public Service Announcement**
At this point, I probably seem like an asshole that is just picking apart anything he can find. Perhaps… The point of my last two dissections is that using a bunch of fancy anatomical and physiological terms to prove your argument does NOT make you right. It also will not deter people from sifting through the bullshit. I have learned very quickly in this industry to dot my I’s and cross my T’s, and do it in a as simple a way as possible, so that it actually makes sense to people.
Continuing on… We are almost done.
“Grab any textbook on myofascial meridians and understand that the body is meant to rotate and the stable position of the body is through these rotations and primarily external rotation out of the lower body.” Supple Leopard Camp
This is the scientific reference you cite? Myofascial meridians? I love fascia as much as the next guy. It’s very interesting… but it’s theory. I can grab and read any book about astrology too; it doesn’t mean I’m going to live my life by the laws of the Aries (I had to look up my symbol, I swear). Again, referring to this type of stuff is fine, as long as its not your only source, and you don’t make it seem like it is the accepted law of the land.
My Experience and Final Thoughts
“I would say that there is an increase in injuries as a result of poor tech. I have seen a consistent pattern that if they had patella-femoral syndrome from squatting or pulling they push their knees out. I have seen the same pattern with low back injuries in cross fit athletes. More telling to me is once they are out of pain I can get them back squatting and pulling quickly by changing their technique away from the knees out.” -Dr. Brendan Murray
This was Dr. Murray’s final word on the subject. I have seen patterns completely consistent with this in my own clinical practice. Several of the athletes that have come to me with hip, knee, and low back pain demonstrate an exaggerated knees-out position when squatting. Do I have the evidence to prove that this technique is causing the pain? Nope. Do I care to prove that this technique is causing the pain? Nope. All I can say is that when I have athletes demonstrate a balanced foot position and proper pelvic alignment, while allowing the knees to track naturally, it seems to improve symptoms. With those fundamentals firmly in place, then individual tweaks in technique are implemented. As far as my view on taking a scientific approach to this stuff, Mr. Takano sums it nicely in the last installment of the series.
I am still a fan of Kelly Starrett and the Supple Leopard Camp. However, when you attempt to universalize a movement for millions of people, these are the types of issues that arise – misconceptions, he-said/she-said, etc, etc. I do not hate the cue “knees out”. It has its place for sure. I use it, but I don’t abuse it. Let that be a lesson for the kids.
I feel a Part 2 coming on that will be much more informative about how we go about building the squat and teaching joint positions.
- Delp SL, Hess WE, Hungerford DS, Jones LC: Variation of rotation moment arms with hip flexion, J Biomech 32: 493-501, 1999
- Hoy MG, Zajac FE, Gordon ME: A musculoskeletal model of the human lower extremity: the effect of muscle, tendon, and moment arm on the moment-angle relationship of musculotendon actuators at the hip, knee, and ankle, J Biomech 23: 1570169, 1990
- Fuss FK, Bacher A: New aspects of the morphology and function of the human hip joint ligaments, Am J Anat 192:1-13, 1991
- Martin HD, Savage A, Braly BA, et al: The function of the hip capsular ligaments: a quantitiative report, Arthroscopy 24:188-195, 2008
- Jordan SS, DeFrate LE, Nha KW, et al: The in vivo kinematics of the anteromedial and posterolateral bundles of the anterior cruciate ligament during weightbearing knee flexion, Am J Sports Med 35:547-554, 2007
- Yon-Sik et al. Changes in ACL length at different knee flexion angles: an in vivo biomechanical study. Knee Surg Sports Traumatol Arthrosc (2010) 18: 292-297