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Plantar venous plexus and the intrinsic muscles of the foot

Discussion in 'Biomechanics, Sports and Foot orthoses' started by scotfoot, Dec 18, 2015.

  1. scotfoot

    scotfoot Well-Known Member


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    Some time ago I placed a few posts on a site run by OESH shoes . The posts have since been deleted and I still have no answers to the questions raised . Please note that I am not claiming to be an expert in foot anatomy or physiology but I do have a keen interest in the area.



    Abstract from OESH site related to an article on the" foot core system" and containing material posted by me -

    6 Responses
    2. Gerrysays:

    November 8, 2014 at 8:03 am

    Hi Casey
    I enjoyed reading your article but wonder if perhaps the intrinsic muscles of the foot play an important role in supporting the bony arch of the foot even in early stance when they are in a passive state . That is might forces be trasmitted between the bony arch and an under tension plantar fascia via the passive intrinsic musculature . This mechanism could help reduce harmful shearing forces between between the bones of the foot during locomotion and explain the forces which lead to the compression and empting of the vessels of the plantar venous plexus in early stance .
    I would greatly welcome any comments on the above .
    Gerry Farrell
    Glasgow

    Reply

    o Caseysays:

    November 10, 2014 at 11:07 am



    ***Here Dr Kerrigan gave a reply which for copyright reasons I have deleted . In my opinion the reply was not really relevant to what I was trying to say . **

    Reply

    3. Gerrysays:

    November 11, 2014 at 2:55 pm

    Hi Casey
    Might it be ,during early stance when the bony arch of the foot lengthens and the plantar fascia becomes tensioned ,that the passive intrinsic musculature located between the arch and the fascia becomes compressed between the two structures (transverse passive compression ) providing support to the arch and a reduction in the shearing forces between the articulating bones of the foot in the midfoot area ?
    Also ,might it be that the intermuscular pressure generated through the transverse passive compression of the foot intrinsics ,in the way outlined above , provides the primary force for the compression and empting of the vessels of the plantar venous arch ?
    I understand and largely agree with the ?foot core system ? outlined in your article ( although I have to say I am not an expert in either foot anatomy or physiology) but believe that the intrinsic muscles of the foot also act as the core of the foot in a much more literal sense .

    Kind Regards
    Gerry

    Reply

    4. Gerrysays:

    November 16, 2014 at 11:22 am

    Hi Casey
    As outlined above I wondered if the plantar intrinsic foot muscles (PIFM) located between the bony arch of the foot (BA) and the plantar fascia might be subjected to passive transverse compression (PTC)when acted upon by these structures during early stance .
    I also wondered if ,during mid to late stance when the PIFM are active ,an increase in the stiffness of the ?intrinsic core ?might provide even greater support to the BA and its articulating joints .
    So the question for me is -Is there an increase in the intra and inter muscular pressure in early stance and can this be attributed to PTC ?
    An in vivo study to investigate this might involve indwelling intramuscular pressure sensors but why go down this road when such a sensor may already be in place in the form of plantar venous plexus (PVP).
    So can the PVP be looked at in this way? Is the pump emptied by inter-muscular pressure or by stretching and necking down ?
    NECKING DOWN-
    Since the veins of the plexus are elastic longitudinally and viscoelastic transversely the effective emptying of the PVP by stretching and necking down is ,in my inexpert view ,unlikely .
    So if necking down is not the mechanism of PVP emptying then the pump must be emptied by increased inter- muscular pressure .But what cases this ?
    If the pump empties in early stance when the plantar intrinsic muscles are not activated then the pressure must be created by stretching of the PIFM or by PTC.
    A study by BJ Broderick et al(1)showed that the PVP is emptied when a standing individual performs toe curls so it can be inferred that inter-muscular pressure is increased when the muscles become activated and contract. I believe that it is reasonable to think that inter-muscular pressure is therefore not increased when the same muscles become less active and return to their original more lengthened positions .
    So, in my opinion, it is most likely that in early stance the PVP is emptied by the passive transverse compression of the ?intrinsic core? and indeed that the existence of a functioning PVP confirms the existence of a significant level of PTC . I also think it likely that the pressure generated in the pump reflects the inter and intra-muscular pressures generated within the ?intrinsic core? and hence the pressures generated at the interfaces between the core and the plantar fascia and BA .

    I would welcome any comments on the above

    Kind regards
    Gerry

    Gerrard Farrell
    Glasgow

    Ref (1) Broderick et al -Venous emptying from the foot ; influences of weight bearing ,toe curls,electrical stimulation ,passive compression and posture 2010

    Reply



    END OF EXTRACT ------------------------------------------------------------------------------------------





    The following are extracts from a conversation I had some time ago with a Professor Jason Cholewa .Again for copyright reasons I have reduced Jasons reply on 27 May 2014 to a single sentence .Posts are in reverse chronological order and a link to Jasons site is included .









    With regard to my ideas about the possible role that the intrinsic muscles of the foot might play in transmitting forces between the tarsal/metatarsal arch and the planter fascia and to the short foot exercise that you mentioned I had a look for some evidence that this exercise can not only increase the strength of the foot muscles but also that it can increase muscle cross sectional area . I did find one paper (1) that shows that in subjects with pes planus (flat feet ) the short foot exercise can be used in conjunction with foot orthoses to increase the cross sectional area of the abductor hallucis muscle . The abductor hallucis is thought to play an import role in the support of the medial longitudinal arch and I wonder if it may act not only by applying force through its point of insertion but also by acting in concert with the tarsal/metatarsal arch and the plantar fascia to maintain or change tension in the fascia itself.
    Kind regards
    Gerry (blue)
    Gerrard Farrell
    Glasgow
    Ref (1) Jung Dy ,Koh EK ,Kwon OY Effect of foot orthoses and short-foot exercise on the cross sectional area of the abductor hallucis muscle in subjects with pes planus ;a randomized controlled trial J Back Musculoskeletal Rehabil 2011
    By: blue
    27 May 2014, 18:40:59 | blueGo to full article
    Hi Jason
    Thanks for getting back to me and its good to hear that you think my ideas might have some validity. With regard to the barefoot vs shod running debate I?m afraid I know little about the subject and have more of an interest in agility orientated sports such as tennis and also in the heavy throws .
    You mentioned the short foot exercise and it certainly seems to be attracting considerable interest at the moment with new papers being published on a fairly regular basis .
    As you have said previously there is still a lot to learn about the human foot !
    Kind regards
    blue
    By: jasoncholewa
    24 May 2014, 13:40:53 | jasoncholewaGo to full article
    Blue, I think you are on to something. (Rest of reply deleted for copyright reasons )
    Jason
    By: blue23 May 2014, 16:55:42 | blueGo to full article
    Hi Jason
    I recently came across a paper from 2001(1) on the transverse mechanichal properties of skeletal muscle and I think that you might very well be right about training the toe flexors to help prevent injuy .
    My understanding is now that when passive muscle is subjected to transverse compression its behaviour can be predicted using an incompressible viscoelastic model (Ogden) . In addition passive skeletal muscle displays changes in stiffness to changes in rate of load application . Might the intrinsic muscles of the foot act to transmit load from the tarsal/metatarsal arch to the plantar fascia in the midfoot region and thus help to support the bony arch of the foot and help to avoid harmfull shearing and displacement forces between the articulating bones of foot ?
    Also ,in early stance as weight is transferred onto the foot causing a lowering and lenghtening of the tarsal/metatarsal arch and a tensioning of the plantar fascia, might compressive forces act through the passive muscle located between the bony arch and the plantar fascia to effect emptying of the plantar venous plexus ?
    Could changes in the composition of the plantar intrinsics predispose towards injury ?
    Kind regards
    Blue
    (1) Bosboom EM et al ; Passive transverse mechanical properties of skeletal muscle under in vivo compression ; J Biomech 2001 Oct 34(10)


    Optimal Sprinting Performance:
    jasoncholewa.com/2012/11/.../optimal-sprinting-performance-a-foot-feti...

    ?

    ?

    2 Nov 2012 - What is the missing link in training for athletic performance? ... In theoptimal case your ankle remains fairly rigid and you sprint back up with ...



    So why this thread ? With the above in mind does anyone think that a medial arch support might improve venous return from the plantar venous plexus in cases were the intrinsic muscles have been replace by fatty infiltrate?





    Gerry



    Gerrard Farrell

    Glasgow
     
  2. efuller

    efuller MVP

    I remember seeing a video of a foot where radio opaque dye had been injected into the veins. The foot was loaded and you could see a bolus of blood move with the loading. Essentially what you are asking is by what mechanism does loading of the foot aid venous return. I have no idea. It sounds like there is a nice experiment there to see if an arch support aids venous return. I think this is one where experimentation would be a lot better than opinions on the internet.

    Eric
     
  3. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    They do that a lot at OESH; they delete the probing or critical questions. Says a lot about them that they choose not to respond to those and just delete them.
     
  4. Craig Payne

    Craig Payne Moderator

    Articles:
    8
    There is quite a bit here on the plantar venous foot pump. It is interesting to speculate on the role of foot orthotics/arch support actually enhancing the mechanism by applying pressure in the arch - I have no idea if it does or doesn't and there is certainly no data on it .... interesting to speculate though.
    That proposed foot core model is fatally flawed due to the timing of the firing of the muscles involved. Casey just parroted what the original paper on that wrote and demonstrated her lack of critical thinking and analysis skills. She just parroted it as it suited her narrative - if you read the OSEH site, they do that a lot. I debunked it here http://www.runresearchjunkie.com/the-concept-of-core-stability-of-the-foot/
     
  5. Gerry:

    I commented on the OESH site when it first came on-line, questioning their claims, and my comments were deleted within a day. Casey Kerrigan seems to not want anyone questioning her shoes or her claims, obviously. OESH, I believe, wants everyone to think that no one has any complaints with their shoes or their claims, thus they continually edit their comments on their website giving the false impression that everyone loves their shoes and agrees with their bizarre claims. That's not very good science coming a "scientist" who owns a shoe company!

    Here is what I said about the "Foot Core System" on Craig's RunResearchJunkie website:

     
  6. scotfoot

    scotfoot Well-Known Member

    Thank you for your replies.
    There does seem to be a current misconception that medial arch supports cause foot muscle weakening even although there is some evidence that they can actually lead to an increased cross sectional area of the abductor hallucis muscle and strengthening of the flexor hallucis muscle (1). The following suggests a mechanism by which this might happen .

    A recent paper (2) showed that medial arch supports cause significant compression of soft tissues in the arch of the foot.
    A paper produced in 2014 (3) showed that during isometric contraction of a rat gastronemius muscle " increasing transversal muscle loading resulted in an almost linear decrease in muscle force ".

    Given these papers it seems reasonable to suggest a medial arch support will compress the Abdh during midstance in a foot prone to pronation . Perhaps this causes the muscle to compensate by growing so that more force can be produced to offset the compressive effect .




    (1) Jung DY, Koh EK ,Kwon OY Effect of foot orthoses and short foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus :a randomised control trial .

    (2)Sweeney D, Nester C, Preece S ,Mickle K ;Effect of antipronation foot orthosis geometry on compression of heel and arch soft tissues .

    (3)Siebert T, Till O ,Stutzig N ,Gunther M ,Blickhan: Muscle force depends on the amount of transversal muscle loading .


    Gerry
     
  7. Craig Payne

    Craig Payne Moderator

    Articles:
    8
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