Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

The Effects of Orthotic Heel Lifts on Achilles Tendon Force

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Jun 15, 2012.

  1. NewsBot

    NewsBot The Admin that posts the news.


    Members do not see these Ads. Sign Up.
    The Effects of Orthotic Heel Lifts on Achilles Tendon Force and Strain During Running.
    Farris DJ, Buckeridge E, Trewartha G, McGuigan MP.
    J Appl Biomech. 2012 May 8.
  2. markjohconley

    markjohconley Well-Known Member

    I am unable to access the article. My query is how do we get a 18ml heel lift in a shoe?
  3. Admin2

    Admin2 Administrator Staff Member

    Previous study on this:
    The Influence of Heel Lift Manipulation on Achilles Tendon Loading in Running
    Sharon J Dixon, David G Kerwin
    Journal of Applied Biomechanics (1998) Volume: 14, Issue: 1980, Pages: 374-389
  4. davidh

    davidh Podiatry Arena Veteran

    Who reviews these papers:confused:.

    The cohort is too small to derive any meaninful conclusions.

    Foot types (ie tight post muscle groups) were not distinguished between.

    And of course this "Therefore, heel lifts could be used to reduce AT loading and strain during the rehabilitation of AT injuries".

    To which the only sensible response is
    No sh*t Sherlock!

  5. Well, you say that, but Sharon Dixon's study which admin posted above concluded the opposite: "The finding that increased heel lift may increase maximum Achilles tendon force suggests that caution is advised in the routine use of this intervention."
  6. markjohconley

    markjohconley Well-Known Member

    How did the moment arm of ground reaction force and the moment arm of the Achilles tendon about the ankle joint center change from the no heel lift to heel lift in the rearfoot/midfoot strikers? Don't need a diagram, thanks, mark
  7. wdd

    wdd Well-Known Member

    Without wishing to cast nasturtiums upon your professional expertise I must admit to shock at the self imposed limitations expressed in your comment above.

    Personally I have never had any problem getting an 18mm heel lift in a shoe and I am sure that, at a push, I could get a 15cm heel lift in a shoe. But then again size isn't everything.

    I may be forced to retract my above comments as I have just realised that you are not using a linear measurement to describe the heel lift but volume. Unfortunately I am not up to speed on the novel concept of volumetric heel lifts.

  8. davidh

    davidh Podiatry Arena Veteran

    I know, but there's a big "could" in my quote.
    "Therefore, heel lifts could.... etc".

    Sharon Dixon et al's study was carried out on a cohort of 3, with different running styles. I find it faintly ridiculous that anyone could base printed clinical advice, even if it contains the words "caution" and "advised", on a cohort of 3. Mind you, this was over 20 years ago so those researchers may have had a rethink since then:D.
  9. markjohconley

    markjohconley Well-Known Member

    Bill, not with you.
    15 cm?
  10. markjohconley

    markjohconley Well-Known Member

    Goodaye Bill, just realised, all the best, mark
  11. efuller

    efuller MVP

    What is interesting is the difference that was found in the reason for tension reduction as compared to what has been classically taught. The classical reason was that the lift takes the tendon off "stretch". The study found, from my understanding of the abstract, was that the decreased tendon load came from an increase of the lever arm of the tendon at the ankle joint. The plantar flexion moment was the same.

    The plantar flexion moment being the same makes some sense because the task of walking may use the same amount of ankle push.

  12. davidh

    davidh Podiatry Arena Veteran

    N = 10?
    Can't get any meaningful data from such a small sample (IMO).

    Researchers may be directed to other research, or an extended study using the same methodology, but this study on it's own doesn't tell us anything much.

    The paper should be renamed:
    The Effects of Orthotic Heel Lifts on Achilles Tendon Force in a titchy cohort.
  13. David:

    What is better, Davis, no data because no one took the time and effort to do even a small study, or a research study with only N=10?

    Even research projects with large cohorts of N=200, can produce meaningless results if not designed properly. For this reason, I won't dismiss a study with only N=10, if the study was designed well and if the research studied a meaningful clinical question since I know how much time and effort is required to perform even a small study such as this..... it is much better than no data at all.
  14. markjohconley

    markjohconley Well-Known Member

    I've been playing with my skeleton and it's easier to imagine a DECREASE of the lever arm of the AT relative to the ankle joint. What am i missing? thanks, mark
  15. davidh

    davidh Podiatry Arena Veteran

    Well, I kind of agree with this, but the results would have been far more meaningful if the cohort had been much larger.

    As it stands it may be a good starting-off point, but as a piece of stand-alone research it's pretty light.
  16. efuller

    efuller MVP

    The lever arm of the tendon is determined by the perpendicular distance from the line of action of the force (direction of pull of the tendon) from the joint axis in question. Schematically, you can model the foot as a triangle with one side of the triangle on the ground. The ankle axis would be at the angle opposite the side on the ground. The Achilles tendon will pull upward, mostly so the direction of pull will stay pretty close to the same. However as you rotate the triangle, into plantarflexion, around the ankle joint axis and extend a line vertically from the attachment of the Achilles tendon, the distance from that line to the axis will be greater.

    Not at my home computer with line drawings that might help. Hope this does.

  17. efuller

    efuller MVP

    I wouldn't dismiss this study for the small N either, especially since it makes sense. I've always had a problem with the lift takes the tendon off stretch explanation because the tension in the tendon comes more from active contraction of the muscle rather than passive tension at the end of excrusion of the tendon.

  18. markjohconley

    markjohconley Well-Known Member

    Thanks Eric.
    I drew a diagram, and comprehend now,

    Attached Files:

  19. musmed

    musmed Active Member

    bloody hell
    now we are dealing with a short leg= SIJ problems and L5 facet disease
    as well as poor knee extension control
    keep going and we will all be the from end of the wheel barrow race without a euro.
    hell I should not have said that

    oh well, up the aussie dollar (for what it's worth)

    night time here, weather beautiful
    great place to live
    Paul Conneely

    stop being so serious. it makes life easier and more enjoyable.
  20. ackers

    ackers Member


    From my clinical guidelines, I always apply a heel lift to both limbs to keep limbs as level as possible at pelvic level, and time of treatment with heel lifts would be kept to the minimum time to recover from AT injury.
    How long in heel lifts would be required for L5 facet disease?
  21. musmed

    musmed Active Member

    Dear Vaughan

    Hi, a very good question indeed.
    Children with slipped femoral epiphysis can develop the problem with 10 years.

    I am presuming the soul is older and if they have some degenerative disease process going on it will accelerate it within a matter of weeks.
    I have seen this in a 54 year old male a few weeks back.
    They felt a twinge within 2 days of a 10mm lift.
    Radiology shows moderate disease.
    It was there, but did not need much to start it become a pathology
    Paul Conneely


    absolutely beautiful sunny day in smoke
  22. Craig Payne

    Craig Payne Moderator

    Sorry, a bit late coming to this:
    I would never reflexively dismiss a study based on sample size. That is why we have effect size calculations. Doing a within subject comparison you can get away with smaller sample sizes than with between subject comparisons.

    To blindly dismiss a n=small number study without looking at the nature of the design (within subjects vs between subjects); the effect size; and Eric's point of theoretical coherence is just as flawed as doing an unethical study by including more subjects than what is actually needed (which is why we have sample size calculations)

    Sharons study was a n=3 and all subjects moved in the same direction....that has to be explained.

Share This Page