Practical Science on Movement and Pain

Dem Bones: Skeletal Structure and Movement Function

I don’t write about structure that often on this blog. That is not because I don’t think structure is an important determinant of how we move and feel. Structure is incredibly important. It’s just that, unlike function, structure is pretty tough to change significantly in the short term. The best example of the stability of structure is the bones. Here are some brief thoughts about the importance of skeletal structure as a determinant of movement quality.

Why skeletal shape matters

The shape of the bones at a particular joint will determine the neutral position for that joint. I am going to define “neutral” as a mechanically optimal position for a wide variety of functions, such as moving in any direction, or being capable of sustaining heavy compressive forces with maximum stability and safety. For example, when the shoulder joint is in a neutral position, the ball of the humerus is well located in the socket of the scapula so that arm can move left, right, up and down without running out of room in the joint or impinging bone on bone. And it can withstand a compressive force down the shaft and transfer it to the scapula with a minimum of shearing forces and risk for damage.

Optimal alignment or posture for a certain function is partly a result of having as many joints in neutral as possible at any one time. And the shape of the bones will determine how many of your joints you can keep in neutral at the same time in a particular functional task. Here’s a very simple example. An internal tibial torsion means that the shape of the tibia bone tends to twist inward as it moves down from the knee to the ankle. If this is the case, then it is impossible to have the knee and ankle pointing directly forward and in neutral at the same. Any effort to point the knee directly forward will tend to point the neutral ankle a little inward, causing pigeon toes.

Another commonly identified bony variation is hip anteversion. Someone with hip anteversion has a particular angle of the femoral neck which causes the lower end of the femur to rotate inward while the femoral head is centered in the hip socket. A person with an anteverted hip will stand with their knees pointed inward, and be able to demonstrate a large range of motion into internal rotation with very little external rotation. This makes it very easy for them to sit in the “W” position.

Personally I have the opposite situation – my hips are relatively retroverted. This makes it impossible for me to do various movements that require a significant amount of internal rotation at the hip that I can see other people doing quite easily. My sensation as I try to do these movements is not that any muscular tightness is preventing me, but instead that I would literally have to dislocate some joints to do the movements.

Of course, these bony asymmetries are not “conditions” that you either have or you don’t. They all exist on a spectrum, and they are not limited to the tibia and femur. Every bone in the body can be shaped relatively closer or further from an optimal shape for certain functions.

Based on this logic and my own observations with clients and myself, the shape of the skeleton is a huge determinant of functional or athletic ability. I think part of the reason we can recognize a great athlete by a few simple movements is not just the quality of their function but the quality of their structure. An optimal skeletal structure makes it quite easy and natural to place all of the joints in neutral positions at the same time. People with skeletons that do not allow them to do so must make compromises, and these reveal themselves in suboptimal alignment, decreased ranges of motion, and reduced efficiency.

Practical implications

So what can we do with this information? Other than form some plausible excuses about our athletic failures? (which I find particularly appealing).

First, we should be very wary about anyone dictating to us what proper form is in regard to a particular activity without considering our individual variations in structure. Let’s go back to the example of tibial torsion to understand why. It is commonly recommended that proper alignment of the foot and knee in running, walking, standing or squatting should involve the knee and the foot pointing in the same direction. This is certainly a good guideline, but let’s look how it plays out in the case of someone with a tibial torsion.

If you have a tibial torsion you cannot have both the ankle and knee pointing directly forward while both joints are in neutral. Perhaps you can achieve this by taking one or both joints out of neutral, i.e. positioning one joint closer to the end range of motion on one side than the other. This arrangement of the bones might look good in a picture or be appealing to a coach who is overly concerned with alignment. But it will probably have several drawbacks: it might require extra muscular effort to hold the joints away from neutral; it will reduce the available range of motion in at least one direction; it will reduce the ability of the joints to bear compressive forces. These negative factors may very well outweigh any positives gained by getting the knee and foot to point in the same direction. Of course we can think of similar scenarios in regard to any joint and the advice that is commonly prescribed in regard to the optimal alignment of that joint.

And here is where I diverge into one of my many sidelines on why I like the Feldenkrais Method. The Feldenkrais Method attempts to teach coordinated movement not by dictating any particular form or alignment, but by allowing the student to determine this issue for themselves based on their own experiments. The idea is to create the circumstances for the student to play with different forms of alignment or body use, assess the relative outcomes, and then make their own choice. This will hopefully result in the student gaining more awareness about which movements are optimal for their particular structure. This will lead to a more individualized and authentic movement pattern than one imposed top down by a coach according to some Platonic ideal.

What about trying to change the shape of the skeleton? The shape of the skeleton is not that changeable after maturity. Of course it will change slowly. According to Wolf’s law, bones will tend to remodel along the lines of stress caused by compressional forces and pulls from the muscles. But this is of course a lengthy process that takes many years. And there are probably not many people that have the discipline or skill to strategically apply targeted stresses to their bones frequently enough and long enough to affect significant changes in their skeletal shape over the course of time. So in other words, the skeletal shape you have as an adult is one that you will probably be living with for some time. Deal with it.

What do you think? Is this post just a way for me to whine about my tibial torsion and retroverted hips? Leave a comment and let me know.

If you enjoyed this article, maybe you will like this one, about visualizing the skeleton while moving, or this one about the obsession with symmetry, which is a guest post I did at Saveyourself.ca.

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20 Responses to Dem Bones: Skeletal Structure and Movement Function

  1. Ryan Flowers says:

    Nice article Todd. Refreshing to hear some of these points mentioned when all too often people are being told to line this up with that, even this out here, push this down there…. despite the intuitive uneasiness it may bring. This is often a tragic flaw in many ‘structurally’ based models of care. Tibial torsion and hip anteversion/retroversion are excellent examples that often leave people forcing an otherwise stressful movement pattern on themselves. Another reason for better screening and ‘treatment’ of pediatric populations, when this is potentially more amenable.

    Maybe a model more realistic is one that encourages balance in structure and movement alike. There’s a big difference between ‘balance’ and ‘symmetry’. Furthermore, our visceral anatomy is asymmetric form one end of the tube to the other, as well as neurologic function from the start.

  2. Jim Hansen says:

    Well, this is one of the few articles that I have seen that addresses both my problem with both tibial torsion and femoral anteversion on my left side and tells me what to do about it: nothing, I guess. It stinks to be a runner with both problems. My knee goes in, but my tibial torsion points my foot out. It also sound like it may be the problem with the left leg of last year’s world champion 400 meter runner Kirani James: http://recoveryourstride.blogspot.com/2012/03/world-champion-kirani-james-and-his.html Does that sound like the same thing? He says this about his and his dad’s foot, “our hips face inwards so our knees face inwards, and the leg sways outside.”

    • Ryan Flowers says:

      Jim,

      Keep in mind that tibial torsion is also a functional component of normal biomechanics of the knee. It naturally goes through a small range of internal and external rotation, the tibia in relation to the femur… external rotation as the knee extends, internal as it rotates. Get yourself properly assessed before ruling it out as there are functional restrictions in this range that can occur and be the cause of this issue, particularly when it present unilaterally. External fixations are not unusual. Looking up and down the chain is important with this consideration.

      Ryan

      • Jim Hansen says:

        Ryan,
        I am sort of teaching and learning myself about how my body works and seeing a lot of doctors and specialists too, but it is hard to get information from them. Functional vs. mechanical is something I am thinking about recently concerning the tibial torsion. I have been running competitively for close to 40 years and I have always had something funky about my left leg. I have been trying to fix my stride and pain-imbalances since doing Ironman distance triathlons in the 1980s which messed up my back (I thought). I realize now it was my hip. I just had labral tear surgery in that hip last July. I got checked out in Dec. by a doctor who measured 45% tibial torsion, but I noted it was much worse at that point in time than before. Then I had a podiatrist do some manipulations on my fibula, cuboid, and some other foot bone and it seemed that the torsion was cut in half and I was more comfortable, so I guess some is “just me” and then it can be made worse by things getting stuck. After coming along nicely in my running since then, I hit a road block again and I notice the foot is pointing with much more “torsion” and then I get pain in the glutes. I guess I have to learn how to get rid of the restrictions. I have seen so many people and no one can put the whole thing together for me yet. It is a puzzle.

        • Mark Hollis says:

          Jim – After 40 years of competitive running the fact that you’re still puzzled is a good thing, it means that you’re still interested, you’re still thinking, you’re still passionate, and you’re still active! You’ve already won the majority of the battle, good luck with the rest of it.

          Todd – Thanks for another great article, always a good springboard for some discussion at the clinic.

    • Todd Hargrove says:

      Hi Jim,

      Interesting about James, thanks for sharing the link and nice article. I can’t tell if its the same thing, but I guess that proves that a few twists and asymmetries here and there won’t necessarily prevent you from reaching the highest levels. And, as Ryan points out, what appears to be a structural issue might in fact be functional, so I wouldn’t say “do nothing” as long as there is a chance to improve function!

      • Jim Hansen says:

        Todd,
        Kirani was only 18 when he won the World Championships. I hope he doesn’t develop problems down the road. Do you think Feldenkrais helps with something like this? or do the restrictions require mobilizations or manipuations? I have played around with Feldenkrais in years past and have been working with Somatics post surgery. Interestingly enough, I saw someone bring up a similar type of thinking related to structure (even mentioning ante-retroversion and tibial torsion) to your article just today on a long ongoing thread on a running message board relating to “loss of coordination” issues when running. I haven’t seen much written on this at all and then two things in two days. Cool!

  3. Great Todd.

    This should be referred to anytime someone says that those of us who attend to the ectoderm have “abandoned” everything else.

  4. Ryan Flowers says:

    “internal as it flexes”… it should read….

  5. Ryan Flowers says:

    Is it really accurate to assume it is this absolute Barrett?

  6. I am so glad you are discussing other aspects about the body besides the musculature in relation to structure. Indeed the bones need to be aligned to be neutral however this does not happen independent of the Fascia, or musculature for that matter. The fascia is everywhere in our body, it creates the shape and alignment of the structure in our body.
    “An optimal skeletal structure makes it quite easy and natural to place all of the joints in neutral positions at the same time”. I like this quote and I believe this aspect of our structure that Rolfing, Aston-Kinetics and Anatomy Trains looks at gives us a chance to change what we believe to be unchangeable. Granted, if someone has a true bony deformity, that cannot be changed by structural bodywork, however much can be. Aston-Kinetics is particularly effective at addressing the joints. Also Aston-Kinetics concepts integrate the asymmetry of the body through movement (due to any cause) in order to function optimally.

    Get the to an Aston-Patterning practitioner! Your structure will love it!

  7. inbar says:

    Jim,Ryan,
    Correct me if i’m wrong,
    My understanding is that a retroverted hip is an increase of external rotation with an equal loss of internal rotation in both hips, pain free.
    antreverted hip will be the opposite.
    emphasis on pain free, resilient end feel of the joint and an equal loss on both sides.
    If it is just the left side maybe it is not a retroverted hip situation.
    thanks for the post.

  8. Ryan Flowers says:

    Hi Inbar,

    Anteversion and retroversion are describing the rotation of the femoral condyles in relation to the femoral neck. There should be no hard end feel as a result, as you mentioned. Yet with anteversion, external rotation as measured by the condylar angulation will be less than that of someone without this condition peresent… As the femoral head will max out in the same manner as a ‘normal’ femur, but with the torsion of the neck and shaft the orientation of the condyles will be less. Same is true in reverse for retroversion. This is different than mere external or internal rotational limitation/fixation of a ‘normal’ femur. It is rather the measured angulation within the bone itself.

    Pain is not synonymous with this, but can develop earlier or later in life for many as a result of excessive strain on soft tissue components of the hip, knee, ankle, foot as well as irregular force transmission through the joint surfaces on the ankle and knee particularly. Walking or running with the knees pointing externally or internally causes torsion and shearing forces at the knee joint, as its axis for movement is designed for straightforward tracking. Pain may arise secondarily to these conditions as a result of pathological biomechanics and premature wear and tear. Some may argue the whole pain phenomenon, but that’s my clinical observation. Unfortunately pain is not black and white, ‘always’ coinciding with a condition or not. And there is no simple answer that can change that.

    As for Jim… I was not at all suggesting he had one, and I hope that came across clearly because I’m not into diagnosing problems on the internet. In fact I suggested it may not be the case, but rather a functional issue. What Jim was describing in himself was (potentially) a femoral anteversion because the knee is pointing inwards, and as a consequence you will see a compensatory external tibial torsion attempting to point the foot forward or externally a bit. This is pure speculation as far as Jim goes because as I said above, he needs to be assessed properly, in person by a qualified professional to determine what is actually happening with him. He may or may not have a true anteversion… A Craig’s Test could be done, among others to assess this. Also, you’re right that ‘most’ ante/retro-versions occur bilaterally, but not always. There is no clear explanation of its cause, although common belief is either a genetic/familial component or positioning in the womb… .

    Hope that clarifies where I was coming from.

    Cheers

  9. Terry says:

    Great article. I am 43 yrs old and a new CrossFitter who was diagnosed with tibial torsion about 5 yrs ago. I am going to share this with my coach, who is a ‘movement’ guy (education, certification, etc) so this should really resonate with him.

    Since I am doing some CF moves for the 1st time in my life – literally – I have noticed some quirky things. Most notably, anything that requires me to be in a deep squat position, which is quite a few in CF (all forms of squats, cleans, and snatches.) I just feel crooked and out of balance when down there. Of course, it gets worse with weight overhead. Also, when coming up out of a deep squat, I feel like I am completely relying on my ‘good’ leg.

    Of course, I too enjoy being able to use tibial torsion as a logical reason why I suck at CrossFit!

    I had knee pain at the time I started. It’s gone now, and the culprit appeared to be lack of ankle mobility in the leg that has the tibial torsion.

    Thanks for the article!

    • Todd Hargrove says:

      Hi Terry,

      Even though you don’t have perfect bones, keep in mind that almost no one does and that you probably have a lot of rom for improvement in your movement patterns. Maybe someday you will find squatting to be quite easy and natural. But also keep in mind that great squatting for you may not look like great squatting for someone else. Good luck. My personal experience is that my tibial torsion does not prevent pretty good form if I go slow.

  10. N.B. says:

    Hi! I am a female and was wondering if Internal tibial torsion could effect sexual positions. While “on top” of my partner, The up and down movement feels challenging. And at times I have heard and felt my hip pop but it does not hurt.

    • Todd Hargrove says:

      Well I would need to see a video to answer that. Sorry for the lame joke, I couldn’t resist. I’m not sure how tibial torsion would make this harder, but I suppose its possible. But regardless of the orientation of your bones, you may have a lot of room for improvement in the mobility of your hips. Work on that and see if it helps! Good luck!

  11. pam says:

    OMG, you just describe me.
    i can sit comfortably in W; my knees turn in. i can make them parallel parallel only with some force. (it sucks big time in ballet class.)

    all teachers various physical disciplines try to correct my stance that i’d wreck my knees by sitting in W. but they’re ok.

    thanks.

  12. Samantha says:

    This is a great article and website. Thank you for the information! I have a question- I am a runner and love yoga. Originally I thought that I would never be able to have the best of both worlds because running tightens my hamstrings too much. But now after reading this article, I am beginning to think I might have a structural or bone issue which makes certain stretches virtually impossible. My lower back is always painful, and I cannot even sit in a “V” without extreme discomfort while everyone else in the class can comfortable sit in a near “Split” position while leaning forward. During toe touching excercises, I can touch my toes, but my middle section does not flex over my legs like it does with other people. I’ve been doing yoga for years and should be up to speed with everyone it seems to me. Other than those positions, my flexibility is fine when it comes to doing advanced poses like back arches, arms, quads, etc. Any advice?? Thanks!!

    • Todd Hargrove says:

      Hi Samantha,

      Thanks for the kind words and glad you like the blog.

      Yoga classes tend to attract people that are more flexible than the average person. In fact they tend to attract people that are more flexible than you might want to be. There are some movement experts like Gray Cook who like to measure what they consider to be appropriate mobility from a sporting or functional perspective, and they consider an appropriate range of flexion to involve touching the toes. Being able to put your palms flat on the floor like you would often see in a yoga class is actually considered hyper flexible or even a dysfunction. So I definitely wouldn’t worry about trying to emulate other people you see getting into the splits or extreme flexion positions in your class. Just listen to your body and try to explore ranges of motion that seem useful, while making sure that everything feels comfortable.

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