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Hip musculature and position and its effect on foot pronation

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Sammo, Mar 14, 2008.

  1. Sammo

    Sammo Active Member

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    Hi all, been an active (viewing) member for the last couple of weeks and I believe I am hooked!

    Just looking for some clarification on a point a colleague and I are mooting at the moment. I apologise if any of my terminology is inappropriate and do hope that you will bear with me whilst I try to articulate my point :D

    I was wondering if there is any evidence to show if foot position is effected by the muscles in the hip (controlling internal/external rotation) and especially the position of the pelvis (anterior/posterior tilt). I'm also wondering how much "core stablility" effects these factors.

    It is my understanding that anterior pelvic tilt leads to internal rotation at the hip, thus internally rotating the femur and translating down the leg. I believe that this internal rotation will thus have an effect on the foot by increasing the pronatory moment at the STJ (due to the medial shift of the STJ).

    My position in this discussion is that I believe that if there is an anterior pelvic tilt, and it is one of the possible causes in foot pronation, it can be corrected somewhat by a course of strengthening exercises for the abdominals. The aim of this to bring the anterior tilt to a more "neutral" or "balanced" position -> externally rotating the hip -> ultimately reducing the amount of pronatory moment in the stj. As I understand this is the converse view to the Kinetic Chain theory.

    I believe that in conjunction with orthotics (should they be indicated) this will be a more effective treatment than orthotics alone. Alas, I have no evidence to support this argument.

    Any thoughts would be greatly received!!


    Sam Randall
    Last edited by a moderator: Mar 14, 2008
  2. Craig Payne

    Craig Payne Moderator

    The only way any sort of exercises aimed at changing hip musculature strength and/or timing of muscle activation to improve foot function will work is if there is hip musculature strength and/or timing of muscle activation dysfunction that is causing the abnormal foot function.

    Think about it, for eg:
    * patient has a forefoot varus; the medial side of the foot has to pronate to get to the ground; how is any sort of proximal muscle exercises going to affect that?
    * restricted ankle joint ROM; one way for the tibia to move forward over the ankle is for the midfoot to collapse; how is any sort of proximal muscle exercises going to affect that?
    * if a FnHL is present, the foot compensates for the temporary block at the first MPJ with some midfoot collapseL how is any sort of proximal muscle exercises going to affect that?
    * etc
  3. Forefoot varus you say? ;)

  4. Sammo

    Sammo Active Member

    Hi Craig,

    Thanks for your thoughts on this topic!

    I understand that if there are problems present in the foot that cause compensatory mechanisms to be used, this will possibly negate any effects of proximal effects, but it depends on the problem..

    What I am trying to say (in a round about sort of way) is this...

    In a patient with pronation compsensating for a forefoot supinatus causing, for example: plantar fasciitis and FnHL. The treatment plan for this person will normally, from a podiatric perspective, include orthotics to try to adjust the position of the foot into one more tolerable by the tissues being stressed. If this patient has poor muscular function around the pelvis which is leading to anteversion (which my physio friends will have be believe is a common phenomenom), will strengthening these muscles (with the intent of correcting the anteversion, thus externally rotating the hip/leg) have an effect of sufficient magnitude, to aid the treatment plan by reducing the pronatory moment caused by an internal hip position? And have any studies been done to this effect?

    Kind Regards

    Sam Randall
  5. I am that colleague. Which is why i was keen to encourage sam to ask the question.

    For clarity, i beleive the question Sam is driving at can be expressed mathematically.

    Pronation => Transverse plane rotation in the leg => anteversion of the pelvis

    Can we therefore say

    Retroversion of the pelvis => transverse plane rotation in the leg => supination?????

    Hope Sam does'nt mind me trying to clarify.

    My view (for what its worth) Is that the volume of supination moments derived from the external rotation of the leg occasioned by retroverting the pelvis are too small to effect a substantial change to WB foot pathology.

    When the foot starts to pronate the leg will have further to internally rotate if it starts in a more externally rotated position. However i do not beleive that the resistance to this relatively small extra amount of movement from the proximal muscles will be sufficient to make much of an effect on the STJ.

    However before we came to blows i advised Sam to seek answers from greater minds than mine.

  6. Sam:

    I know that Irene Davis, PhD, has done research showing that runners can be trained to run differently (i.e. less internally rotated knees) using pure muscle control. In addition, there is a very interesting acupressurist here in Sacramento that trains people to walk with less pronated gait patterns without foot orthoses. So gait training can be done and this may somewhat be caused by a change in hip muscle firing patterns.

    A simple lesson of the STJ axis location/rotational equilibrium theory is that it is the summation of all the STJ pronation and supination moments at any given instant in time, no matter what their source, that determines the net STJ moment. This means that hip control can be just as effective as orthosis control of pronation, theoretically.
  7. Ian Harvey

    Ian Harvey Active Member

    Hi Sam, Craig and Robert,

    I have just recently been thinking about hip position and would appreciate some feedback from colleagues.

    It seems to me that the position of the hip might have certain effects on the foot. For example, if the hip is externally positioned, then the feet are likely to be more abducted (assuming no other "deformity".

    This would cause a more lateral heel strike with increased pronatory forces from the rear foot.

    If the hip is internally positioned, then the feet are likely to be more adducted.

    This could result in less pronatory forces from the rearfoot, but increase the pronatory forces from the lateral side of the fore foot.

    Perhaps colleagues with foot pressure measurement facilities could comment?

    I have just tried to test this hypothesis by alternately walking with my feet abducted like Charlie Chaplin, then with my feet turned in. It's not easy to be truly objective when testing yourself, but if you try it yourselves you might feel increased pressure on the lateral fore foot when adducted.

    I suspect that hip and pelvis position is a contributor to pathology, but not sure how significant this is.

    I also suspect that the foot pathology could affect the hip position, by proximal compensation over a long period of time.

  8. Ian Linane

    Ian Linane Well-Known Member


    Whether this is pertinent I don't know but when you apply a peripheral joint mobilisation to the hip of a leg that is exhibiting circumduction and more external rotation than you would like (and that external rotation and circumduction is linked with muscle rather than joint issues) then it is not uncommon to see some change in foot function resulting from the mobilisation of the hip.

  9. Sammo

    Sammo Active Member


    Thank you very much for the information.. Sorry to trouble you further, but would you be able to point me in the direction of any papers on this subject?

    Ian (Harvey),

    What you say I believe to be correct to a degree.. but also think about what happens to the position of the foot in the frontal plane with internal and external rotation of the leg, where the foot does not ad/abduct.. try standing and tipping the pelvis anteriorly then posteriorly (with out allowing the foot to leave it's starting position) and see what happens to it with regards to pronation and supination!

    Kind Regards

    Sam Randall
  10. Hmmm

    I can see that starting the leg off in a more externally rotated position will position the foot in a more supinated position at heel strike (theoretically).

    What i cannot see is how this can generate a meaningful amount of supination moment when the foot starts to load.

    Considering the relatively small amount of actual rotation which takes place it would seem to me that the musculature involved in rotating the leg is working at a huge mechanical disadvantage compared to the gravitational forces exerting pronatory moments.

    Put another way, with a patient in static WB i can (in most cases) supinate the foot by recreating the tibialis group function (applying upward force to the mid tarsal area). I'm not sure i could bring a foot into supination by trying to externally rotate the leg.

    What it boils down to i guess is whether performing core stability exercises will significantly affect foot position. So as Sam says, it there any meaningful research on this?

    Another question is, is there research which shows that core stability exercises can affect lasting change to the pelvic position.

  11. Craig Payne

    Craig Payne Moderator

    I knew someone would come back at me with that one....buts lets just pretend it exists for the sake of illustrating the point.

    There is no doubt that there are proximal influences on foot function in the same way that foot function affects tissues proximally.

    What I have an issue with is those (most physiotherapists) who have this belief that you do not need foot orthotics and just need to strength the external rotators about the hip. Forefoot varus is a good eg to explain to them why they are wrong....it will not matter how strong the hip external rotators are, the medial side of the forefoot has to get to the ground (they can understand that).

    The only time that strengthening the external rotators of the hip to stop the foot pronating will be when the weak external rotators of the hip are the cause of the foot pronation.....I have never seen it and wish someone could show me a case.
  12. Craig Payne

    Craig Payne Moderator

    Not to be pedantic...but a forefoot supinatus is the result of a compensation and does not cause a compensation
    I am not aware of any studies that show that strengthening the muscles actually work to correct this
    I would say NO. You do not get a forefoot supinatus unless the calcaneus goes past vertical (allegedly). How would the anteversion make the calc go past vertical. Something must have made the calc go past vertical to cause teh supinatus (allegedly).

    I am not denying that proximal issues influence foot function ... it just the jumping on this band wagon by those with a poor undertsanding of foot function tat I have the issues with.
  13. Sorry Craig;) Could'nt help myself.

  14. Admin2

    Admin2 Administrator Staff Member

  15. Sammo

    Sammo Active Member

    Hi Craig, My point was not whether hip position would be a sole solution (excuse pun) to pronation, but whether it would have a positive effect in an overall treatment plan, in the right case.

    I am a podiatrist with (I believe) a reasonable understanding of biomechanics (and of course much still to learn), but I feel that in the profession there are too many people that focus perhaps a little too much on the functions below the knee when diagnosing and treating foot pathologies to the detriment of diagnosis and possible treatment plans. I am trying gain a more holistic understanding of the body and trying to establish whether things further up the chain will have a significant effect on things distally, to further myself as a practitioner (however I can't keep out of my head references to that cat that succumbed to curiosities urges!!!)

    I feel that I understand some of your frustration at people with limited understanding jumping on band wagons and talking about things outside of their remit and skill set... there was a post on this site that I read recently about a physio giving a talk on BBC radio about conditions in the foot and getting the whole thing pretty horribly wrong, which made my blood near boil. Also, I spent a little time in my career temping for a company called Dr. Scholl (I see the collective shuddering of UK podiatrists upon reading this!!). The manager and staff were under pressure to sell their insoles, so any one that looked like they had a foot that "rolled in" were targeted for their sales.

    Also, to some extent I was playing the advocate for the sake of the discussion I was having with my colleague Robert.

    There are, however, a couple of questions I would like to put to you, and everyone interested on this post...

    If forefoot supinatus is secondary to a compensation, it shows that the forefoot is flexible, and under the correct conditions, the soft tissue structure of the forefoot will change in accordance to the stresses it is under.. therefore, for the pure sake of academic argument, if the rearfoot was to change overnight to a less everted position and this required the forefoot to plantar flex more on the medial side to contact the floor, then it could do this...?

    Also.. it is my understanding that when the pelvis tilts anteriorly the axis of the hip joint changes. I.e. when you have anterior tilt; the range of motion at the hip in the transverse plane is shifted internally and vice versa. Therefore, if the pelvis is put into a less anterior position, the ROM is shifted to a more abducted axis in this plane.

    It is my understanding that this is what Kevin's post alluded to, and if I have misinterpreted these points I apologise profusedly to all parties. Also, if the statements I have just made are pure myth, I will gladly keep shtum and save myself more embarrasement :eek:

    Again, I am sorry if my terminology is wrong and I endeavour to be able to articulate a point in the "proper" way. But I am hoping you will understand the idea behind the text and, along with corrections in my vocabulary, help me to glean a fuller understanding in the functional anatomy and biomechanics of gait.

    Anyway... my friends are telling me I am being an insufferable geek and I really need to get back to the house party I am currently in attendance of.... CHEERS!!!!!! :drinks

    Kind Regards

    Sam Randall
  16. efuller

    efuller MVP

    Hi all,

    To add what Kevin wrote about you have to sum up all of the moments about the STJ axis to figure out what the STJ will do.

    The question can be reasked as what moments from the hip can be transmitted to the foot to add supination moment. You do also have to think about position. If transverse plane rotation of the leg happens during swing the whole foot will rotate. So, most likely you would change the angle of gait and not joint position.

    When the foot is on the ground, you have to examine how a motion of the hip will create a moment on the femur. I realize that most of the time those motions occur together, but are they truly mechanically coupled? Are they coupled with muscle forces? So, if there is a moment applied to the femur it has to be transmitted through the knee ligaments to the tibia. The knee is not very good at transmitting transverse plane forces. Think of the femoral condyles on the menisci on top of the tibial. When you try spin the femur on top of the tibia what prevents the motion. There certainly is not any bony block to this motion.

    I would agree that any moment from the hip, if it did get transmitted to the talus would be small and would more likely be the result of musclular effort used to stabilize the knee.

    Another way to anaylze the problem is to do the old test describe in Normal and Abnormal Function of the Foot by Root, Orien and Weed. They suggested rotating the pelvis to cause pronation and supination of the foot. However, if you look at the extrinsic muscle of the foot at the same time you do this you will see the peroneals be active in the foot that is pronating and the posterior tibial will be active in the foot that is supinating. (Pain avoidance: you will use muscles to decrease stress on anatomical structures. As the torque is applied from above muscles will contract to decrease stress on structures.) So, try this test without firing your extrinsic foot muscles. You can swivel your hips without moving the joints of the foot.


  17. Sam:

    Here are a few of Irene's papers which highlight the ability to train individuals to use their hip musculature to decrease the internally rotated knee position during running.



    Now, on to the theory. How would one be able to supinate the foot using the hip muscles? Any external rotator of the femur should be able to generate a STJ supination moment during closed kinetic chain motion. If you stand and lift your right leg from the ground by leaning sideways so that the hip and knee remain extended, then you should be able to externally rotate your right femur fairly forcefully using your hip external rotators.

    Using the external femoral rotators while the foot is on the ground will produce an external rotation moment on the talus which will cause a subtalar joint (STJ) supination moment. These transverse plane rotational forces can easily be translated through an extended knee. The question then becomes whether the external femoral rotation moments and STJ supination moments exerted by hip muscles can overcome the prevailing STJ pronation moments from ground reaction force acting lateral to the STJ axis that acts to keep the tibia and femur from externally rotating. This is where a firm understanding of the principles of rotational equilibrium of the STJ and how spatial location of the STJ axis affects STJ moments come into play (Kirby KA: Rotational equilibrium across the subtalar joint axis. JAPMA, 79: 1-14, 1989; Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001.)

    Hope this helps.
  18. DawnPT

    DawnPT Member

    Yes, I know that changes at the pelvis affect the foot position. In theory, strengthening abdominals to improve the pelvic tilt would actually work its way down the leg and ultimately improve the position of the foot. The problem is trying to make an effective difference when the patient is an adult. The bone modeling takes place earlier on, and it is hard to change anteversion/ retroversion, ant/post pelvic tilt, etc without some kind of surgical intervention when older. I have observed therapy techniques for bone modeling work best on 1-3 year olds who are small to medium sized. Anyone older or an exceptionally large child does not seem to produce results.

    The best times for changes for adults would be around puberty (men/women) or immediately after pregnancy (woman of course- although my husband swears his extra 10 pounds was from the baby!) This is the most effective time where the ligaments are loose enough to produce an observable change in the posture of an adult.

    I went to a seminar where an orthopedic PT proposed some information on total knee replacements. He stated that after his patients had TKR, he immediately got them in a supportive ankle/foot support if there was any misalignment. He said otherwise, they would continue to posture their knees to wear down the joint again. I haven't been able to stop thinking about that, especially in regards to pediatrics. Can I help a child to the point where I could help prevent a knee replacement or something similar? I hope so!

    Do any of you guys seen post-operative TKR? Maybe you should market for it and we'd have the repeat surgery down to minimal percentage.
  19. Ian Harvey

    Ian Harvey Active Member


    I agree it seems challenging to correct a bony or ligamentous problem which is causing internal or external positioning of the femur. However, if the mal positioning is caused or maintained by muscle imbalance or tightness, then it should be more feasible to correct that with the appropriate exercise?

    All of this assumes that there is enough mobility in the actual joint and ligaments to allow this extra rotation to happen.

    The papers indicated by Kevin K. certainly indicate that this is possible.

  20. DawnPT

    DawnPT Member

    I think it's a difficult topic to discuss because in theory in should be possible, but in reality, I have not seen a huge functional difference or at least one that carries over into their functional activities. I can stretch the hamstrings and improve the abdominal strength to correct an anterior pelvic tilt, but the biomechanical changes usually are still seen in the knees & feet. I felt like the changes either compensated at a different joint or continued with the anterior pelvic tilt (maybe not as much of an angle). So the pain was improved, but still there. I'm afraid they still would need a TKR.

    I tried to rationalize what I was seeing, and all I could come up with is that I could not produce a huge change. I could maybe help alleviate the pain, but they would still have an anterior pelvic tilt with anteverted hips, genu valgus at the knees, and over-pronation with maybe calcaneal valgus. I've added inserts, but I still wasn't able to get rid of the knee pain. After TKR surgery, things were much better.

    Any ideas? Is there only so much I can do with stretching, mobilizations, etc?
  21. Just come back to this.

    The studies offered by KK (cheers for those BTW:drinks) show some very interesting outcomes.

    Specifically they show that a change can be affected to the kinematics of somebodies running by retraining the muscles.

    The second of the case studies used a series of retraining sessions. 3 times a week for 8 weeks. The instructions stated were to:-

    A: realign her R hip by contracting her abductors and external rotators (without rotating the foot)

    B: Keep her knee facing forward (method not defined, could be with proximal or distil muscle groups)

    C: Extend her left leg further before heel strike.

    The outcomes were good showing a significant change in rotation of the leg.

    I can see how this could be effective, however i can see some problems extrapolating this onto the OP (hip muscles and pelvic position affecting foot position)

    1. These studies are entirely based on hip and leg musculature rather than core stability exercises / pelvic position. This point, for me, remains to be proved.

    2. The concept of gait retraining is one i can quite see being useful in running which is something most will do for a matter of minutes per day (short enough for the patient to maintain focus and concious control of gait) and with higher global tone than walking. I would be interested to know if their are any similar studies carried out with patients walking rather than running.

    3. The "package of care" in these studies was fairly intensive. Most patients will not manage 3 visits a week for 8 weeks! Is their any data for what can be acheived with a series of home strengthening exercises?

    4. The "package of care" also involved several changes on the part of the patient. Is it possible to assess / judge / guess at the amount of change which is due to the strengthening / education of the hip musculature (which i remain skeptical of) as opposed to the use of frontal plane supinators (ie tibialis group) to acheive transverse plane rotation (which would also affect femoral rotation).

    A concise and accurate summation as always. A few thoughts on this.

    If the external Rotation moments exerted by the hip musculature were of a volume as to have a significant role in the STJ rotation, could the rotational stress between these moments and the internal rotation moments created by GRF lateral to the STA cause strain in the knee (from the opposing rotational forces)

    In terms of modeling, how would one go about including hip rotators into one of Kevins thought experiment style diagrams?

    It strikes me that one would need to know:-
    The distance between the insertion of the rotators and the transverse axis of the femur.
    The working range of rotation between heel strike and max pronation
    The planal dominance of the STJ in order to extrapolate the frontal rotational moment from the transverse.

    With this would it be possible to generate numbers for
    A: the internal stain within the knee
    B: the amount of muscle power needed to be generated in the proximal group to exert a given amount of frontal plane moment in the foot.

    To this end, i'm off to give myself a migraine trying to work that lot out. Any guidance would be appreciated, especially if i am barking up completely the wrong tree!

    Kind regards
  22. Transverse plane knee strain is certainly a possibility but probably at no larger magnitudes than would be caused by something very common, such as late midstance pronation, where the pelvis and hip are generating external rotation moments on the femur and the excessive STJ pronation moments are generating internal rotation moments on the tibia (see my previous postings/lecture notes on abductory twist).

    A classic thesis was published by Benink (Benink RJ. The constraint mechanism of the human tarsus. Acta Orthop Scand. 1985;56(S215):49-68) that used the tibial rotation apparatus of VanLangelaan (Van Langelaan E. Relative talotibial movements and relative tarsal movements. Acta Orthop Scand. 1983;204:135-265) to actually measure the amount of external rotational force on the tibia that was required to supinate a cadaver limb preparation from a maximally pronated position. Benink's study is probably one of the best, but least known, studies of it's type and, as far as I'm concerned, it is one of the classics. I read it about 20 years ago and his ideas on force required to supinate the foot and his "tarsal index" confirmed many of my clinical observations and ideas on supination resistance and the mechanical effects of subtalar joint axis spatial location. I believe that Benink's study may be a good start toward understanding how to solve this very interesting problem.
  23. efuller

    efuller MVP

    One of the major problems of using hip musculature to rotate a leg on the ground is that the trunk is not fixed in space. For every action there is an equal and opposite reaction. When the trunk applies an external rotation moment to the leg the leg applies and equal and opposite moment to the hip. If the leg in question was in the stance phase of gait the moment from the leg, acting on the trunk, would tend to move the trunk in the opposite direction needed for forward progression.

    In trying to do calculations for the single leg weight bearing situation, you would have to look at moment of inertia of the trunk. It would seem that a more important function of the hip musculature, in this situation, would be controlling the direction the trunk is facing.

    So, when both feet are on the ground hip musculature could apply an external rotation moment to the femur and the femur could apply an external rotation moment (through the knee structures) to the leg and the leg could apply an external rotation moment to the talus and if the foot was fixed to the ground, you could get supination of the STJ.

    The free body diagram for this is not easy. One one side of the STJ you have the talus and on the other the calcaneus. The moments applied to the talus by leg rotation would come to the talus as a force couple applied to the talar dome from the anterior medial part of the tibia that touches the talus and the posterior lateral part of the fibula or if its the soft tissues that supply tension forces, then you need a three dimensional representation of these forces relative to the STJ axis. A simple one plane diagram would not give a simple solution to the moment at the STJ created by the above forces acting on the talus.

    Kevin's approach was a good one. You know that an external rotation moment applied to the talus will cause a supination moment. There are moments applied by other things, e.g. muscle, ground and the net moment determines what will happen. So the way to figure this is out through experimentation with cadavers. You could try and figure it out with finite element analysis, but it would be easier to look at a cadaver to see if a loaded leg that had an external rotation moment applied to could supinate the STJ. It would also be interesting to look at knee ligaments at the same time.


    Eric Fuller
  24. Agreed! I am gamely trying to generate a model but its a mite tricky to say the least!

    Thanks for the reference kevin (its here http://www.ptjournal.org/cgi/reprint/78/4/404.pdf BTW Sam, If i'm going to be up late on this one so are you!)

    I'll have a go over it.

    Eric, you say that it might be easier to look at a cadaver, that very much depends on how easy it is to access a cadaver! I'll check the stock cupboard but i'm pretty sure we're fresh out!

    Mind you Sam might help me there. Sending me down this line of enquiry and trying to quantify, simplify and understand such a horrendously complex and multifactorial system might cost him dear :mad::butcher:. Not since simon introduced me to the concept of foot / insole / shoe / ground interfaces or Javier asked the innocent question of why we cast a pathological foot has anyone caused me such a migraine. Cheers buddy. Come to work in a stab vest tomorrow if i were you. :craig:

    Thanks for the input guys.

    Back to my lines, moments and hedex.

  25. Dammit! Wrong paper.

    Kevin i don't suppose you have a link to that cadaver study do you?

  26. You will probably need to go to a medical library or order the paper by Benink online (Benink, RJ: The constraint mechanism of the human tarsus. Acta Orthop Scand, 56: (Suppl) 215, 1985.) I made the copy over 20 years ago and it is buried somewhere here in my library of papers. Benink used the same testing apparatus that VanLangelaan used. Both Benink and VanLangelaan were students of Antony Huson.
  27. Robert:

    I have now located my Benink paper and if you want a copy, e-mail me privately since it seems to be too big to attach with Podiatry Arena for some reason. It is 7.5 MB in size.
  28. Given the importance of this work I believe that it would be very helpful if this was sent to Admin, so that he could make it accessible to all the members of the community who haven't read it. I'm sure he can break the rules on attachment size ;)
  29. Robert, Simon and Colleagues:

    I first read Benink's PhD thesis 20 years ago...here is my copy from the old CCPM library. I hope that everyone takes the time to read this classic paper that is virtually impossible to find due to it being a supplement in Acta Orthopaedica Scandinavica.

    Benink used the same transverse plane tibial rotational apparatus as did Van Langelaan in his classic study (PhD thesis also) from 1983 which was also done at Antony Huson's lab in The Netherlands (Van Langelaan EJ: A kinematical analysis of the tarsal joints. Acta Orthop. Scand., 54:Suppl. 204, 135-229, 1983). However, Benink actually measured the rotational force (i.e. moment) required to supinate the foot by externally rotating the tibia and found that lower arched feet (feet with medially deviated STJ axes, I am pretty sure) required more force that higher arched feet (feet with normal or laterally deviated STJ axes). Benink also invented the "tarsal index" which correlates fairly closely with talar head position relative to the calcaneus and possibly also to STJ axis location. Anyway.....it took me an hour to copy on my scanner, is 117 pages long but this paper should be read by (and in the library of) anyone that takes foot and lower extremity biomechanics seriously. Enjoy!
  30. Dananberg

    Dananberg Active Member

    In consideration of this topic, I thought I would describe I case I saw today.

    This is a 64 yo female who I had treated over many years in the past. She had terrible genu varum/recurvatum, and knees that almost subluxed while walking. Aside from her knee pain, she had disabling lower back pain as well. Feet appeared as extremely planus, severely pronated and apropulsive during gait. LLD compounded her problem. She did use the orthotics I had fabricated for her with a reasonably (all things considered) good outcome.

    She is now 6 months s/p B/L knee replacements. Her foot is no longer pronated. There is only a subtle late phase pronation visible. She is incredibly smooth in her walking, and has had an outstanding functional outcome. The surprise is how her feet changed their function in regards to her knee deformation, and then returned to a normal functional attitude when her knee deformity was resolved.

    Although I have always known that top to bottom, or bottom to top is a two way street, this was so remarkable that it was worth sharing.

  31. peter96

    peter96 Member

    I have tried to download Benink's papers from kevins post several times now the download cuts out halfway through and i get an error message when i try to open the file can i do something to remedy this.
  32. Peter:

    Send me a private e-mail and I will send you the papers. Just let me know how large of a file size your e-mail server can handle for download.
  33. Robert and Simon:

    Have you read the Benink paper yet? What do think of the paper? No pressure here....48 hours is allowed.;)
  34. I had the same problem on one computer, but it came through ok on another.:confused:

    Awwww c'mon!! Its 120 pages long!! I've a blister on my index finger and a sore throat from reading out loud!

    Seriously it is very interesting, thanks for uploading it. I'm still wading through it to get to the ratio of YM+/- to XM+/- for my model (think thats right). Which, BTW, became easier by several orders of magnitude when Dave tried to explain the right hand rule to me (equations got MUCH shorter).

    The one i worked out based on a 16 degree axial position was a bit simpler:craig::bang:.

  35. Ok I've got the gist.

    As you say kevin, a very informative paper indeed! A few things i found significant / particularly interesting (i don't doubt they'll be more on a second read). In no particular order:-

    Page 79
    "with increasing Exorotation the skeleton grows steadily narrower because of the overlap of the talus and navicular on one hand and the cuboid and calcaneus on the other"

    Made me think

    That being the case, will an orthotic with a high medial wrap / tight lacing to constrain the expansion of the foot therefore limit pronation by preventing this expansion.

    page 47

    "The external shape of the foot does not provide sufficient information about the mutural relationships of the talus and calcaneus"

    Made me think

    Given that our insoles are based on casting "the external shape of the foot," how confident can we be that our manipulations of the calc / talus (with orthotics) are accurate.

    page 90
    "A comparison of the stepwise movement from 0 - 30 degrees and return with the same movement carried out continous, both before and after dissesction into osteoligamentous preparations, showed once again that , as in the fixed osteo ligamentous material, there were hardly any differences to be observed betweent the intact specimin and the same specimin after removal of skin and muscles"

    Obviously written before the discovery of bio tensegrity :rolleyes:. Are we still waiting for that paper?

    page 67
    Interesting pictures of axial locations! More axial translation than i would have expected. Good to be reminded that the bundle of axis has translation as well as rotation.

    Again, Thanks to Kevin for preserving this useful document for posterity by digitising it!


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