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Achilles tendonitis and transverse plane tibial moments

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Craig Payne, Sep 7, 2012.

  1. Craig Payne

    Craig Payne Moderator


    Members do not see these Ads. Sign Up.
    I missed this in 2008:

    Transverse-plane mechanics at the knee and tibia in runners with and without a history of achilles tendonopathy.
    Williams DS, Zambardino JA, Banning VA.
    J Orthop Sports Phys Ther. 2008 Dec;38(12):761-7.
  2. Admin2

    Admin2 Administrator Staff Member

  3. David Smith

    David Smith Well-Known Member


    This abstract doesn't tell us much or at least its ambiguous, are you able to attach the whole paper for us to read.

  4. David Smith

    David Smith Well-Known Member

    Ah! I Found it

    attached below

    Attached Files:

  5. Leopold

    Leopold Member

    Could someone clarify something from this paper. They state: "abduction in part is controlled by medial ground reaction force." Is that the same ass an adduction free moment?

    I don't see Free Moment referred to very often. It seems that the rotational ground reaction forces should be of significant importance. A few years ago I saw a paper by Milner (I think, but can't find it at the moment). It had 25 subjects with a history of tibial stress fracture and 25 controls. I remember looking at the graphs of the Free Moment in this paper and having my biomechanical world flipped upside down.

    Does anyone have other papers that could improve my understanding of the rotational ground reaction force?

    And, have any specific injuries being linked to an individuals tendency to have a larger magnitude abduction free moment, which to clarify, I believe is referring to the friction of the ground preventing the foot from toeing in?

  6. musmed

    musmed Active Member

    Dear Craig

    Methinks it sounds like they had a plantar flexed first ray secondary to lack of function of the popliteus muscle and thus less internal rotation.

    A sunny day down here in the good country.
    Kevin forgewt that white stuff on your roof!

    Regards to all
    Paul Conneely
  7. David Smith

    David Smith Well-Known Member

    Has anyone else read this paper and found it difficult?

    The main thing to take away from this research seems to be that when the tibia has greater internal rotation the that knee then this winds up the Achilles tendon which has the effect of shortening it (twisting a cylinder reduces its height or length) and generally increasing internal stress particularly in the medial fibres.

    It also states that angular internal tibial rotation is similar in both groups (AT subjects and control) but that internal tibial rotation moments are not similar and that knee internal rotation moments are similar.

    I find it difficult to understand how the moments due to GRF about some point of interest in the tibia can be different to moments due to GRF at the knee??? unless you are using different reference frames for the two segments but it doesn't suggest this.

    If you apply a torque to one end of a bar then it must be the same torque at the opposite end regardless of any deflection along it length.

    If you put a 45degree bend in the middle of the bar and perhaps couple the two segments with a rubber trunion then the moment at the initial segment will be greater than the second segment if you calculate the moment along each ot the longitudinal axes i.e. in two different reference frames. I.E. the moment in the second segment is the sin45degrees of the initial segment moment. Also, if the other end of the second segment is tethered with a similarly stiff trunion then the deflection of of the initial segement would be greater than the second segment.

    Maybe this is what was happening in the research examples??

    goto to go battery running out :eek:

    Last edited: Sep 24, 2012
  8. David Smith

    David Smith Well-Known Member

    ok I'm back on a different PC with power:boxing:

    So, to continue, the implication is obvious, the research concludes that the subject with more tibial rotation than knee rotation has more potential to Achilles Tendonosis (AT).
    My argument above suggests that the more the knee is flexed then the more likely you are to get the above finding.

    If you were a person with a painful ach ten an/or had a tightness in the ach ten that caused you to avoid this, then the way you might avoid this is to flex the knee :cool:
    Therefore it may be likely that AT predisposes the subject to a more flexed knee gait.
    This may lead to a spurious conclusion i.e. the findings are an effect and not a cause or it could be that the effect of a tight Ach Ten causing flexed knee leads to an aggravating factor in AT development.

    Anyone still with me or have I not understood the paper correctly?

    Regards Dave Smith

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