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Heel lifts and achilles tendon tension

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Asher, Feb 28, 2011.

  1. Asher

    Asher Well-Known Member


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    I'm trying to get my head around the fact that heel lifts don't decrease tension in the achilles tendon, in fact, they potentially increase tension.

    If anyone has the following paper, would they be so kind as to forward a copy?

    Sharon J. Dixon; David G. Kerwin: The Influence of Heel Lift Manipulation on Achilles Tendon Loading in Running. JAB, 14(4), November 1998

    Regards

    Rebecca
     
  2. Not the full text but a good summary ?

    http://www.staffs.ac.uk/isb-fw/Manuscr/Dixon05.pdf

    Also I have a copy of - Variations in Achilles Tendon Loading With heel lift intervention in heel toe runners by Dixon and Kerwin if you want a copy of that let me know.
     
  3. Griff

    Griff Administrator

    Hey Rebecca,

    I've got this at home - will email it to you when I get back tonight

    Ian
     
  4. RobinP

    RobinP Well-Known Member

    I thought I had this one but just checked and I don't. Would you be so kind as to e mail it to me as well please Ian?

    Robin
     
  5. drsarbes

    drsarbes Well-Known Member

    ASHER

    "the fact that heel lifts don't decrease tension in the achilles tendon, in fact, they potentially increase tension"

    That is not what this study shows.

    "Compared with zero heel lift, both heel lift conditions resulted in a reduction in peak Achilles
    tendon force and Achilles tendon stress ......"

    Steve
     
  6. davidh

    davidh Podiatry Arena Veteran

    Steve - sorry to hijack your post.

    In addition the discussion says "Alternatively, if peak force is of consequence, the
    success of heel lift interventions is likely to be subject-specific."

    Notice that the study was undertaken with only seven subjects.
     
  7. JB1973

    JB1973 Active Member

    How timely,
    i am potentially doing a talk next month on achilles tendonopathy. Mike and Ian, would you be so grateful as to forward on a copy of the ones mentioned to me as well?
    many thanks
    JB
     
  8. Griff

    Griff Administrator

    Ooops - sorry I don't have this; just had a look and it was another heel lift article I was thinking of instead.

    Apologies all.

    IG
     
  9. JB1973

    JB1973 Active Member

    no problem Ian. Its all this talk of helen Mirren has made you take your eye off the ball!!
    thanks anyway.
    JB
     
  10. Griff

    Griff Administrator

    You're not wrong!

    I've emailed you some papers for your presentation anyway

    IG
     
  11. JB1973

    JB1973 Active Member

    Ah youre a good man and no mistake.
    i'll buy you a beer sometime.
    JB
     
  12. efuller

    efuller MVP

    There is active and passive tension in the tendon. Active is from muscle contraction. Passive from motion of some other part, for example the leg rotating anteriorly over the foot planted on the ground. The tendon, itself, can't distinguish the difference between the two. Tension is tension. So, if a heel lift enabled the subject to contract their gastroc soleus more than without a lift it is theoretically possible to get more tension with a lift.

    I recall one study that was mentioned on the arena that showed that measured ankle dorsiflexion in the chair was 10 degrees and in gait there was an average of 4 degrees. The active contraction of the muscle can prevent the ankle from going to its passive end of range of motion. So, if Achilles pathology is from a longer duration of high tension then I could see a heel lift working better if the passive dorsiflexion was less than 5 degrees. However, it may not help much if the tendon never gets to its passive end of range of motion, because all the tension will be from contraction of the muscle and this will most likely occur with or without the heel lift.

    Eric

    Eric
     
  13. Asher

    Asher Well-Known Member

    Thanks for that Mike.

    Steve, the above summary of the paper indicates that the reduction in peak achilles tendon tensile force was not significant. But the rate of loading of the achilles was statistically significantly reduced.

    What does that actually mean, can someone paint a picture for me? If the peak tension is the same, a reduced rate of loading means it happens quicker. My 'common sense' tells me that it would be better (for injury-prevention) to have the tendon build up to its peak tension over a longer time ie: increasing loading rate.

    Yes please Mike.

    Rebecca
     
  14. efuller

    efuller MVP

    Rebecca, I think you have loading rate backwards. Rate of loading would be change of load per unit of time. A reduced loading rate would be where the time to peak force would be longer.

    Eric
     
  15. Asher

    Asher Well-Known Member

    Yes, I think so. Thanks for your patience Eric.

    Rebecca
     
  16. Asher

    Asher Well-Known Member

    This one shows that indeed some people exhibit increased Achilles tension with a heel lift. Unbelievable!

    Rebecca
     
  17. footdrcb

    footdrcb Active Member

    Common sense in the world of theory is always bloody good mate... I agree > In order to "prevent"further injury .. Hence the gradual reduction in the lift and mobilisation ..... Your thoughts are well within the realms of the real world .

    all the best

    FDCB
     
  18. Rebecca have you read this thread in light of the papers - http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=16267

    Craig P mentions the same papers, Dave Smith draws some diagrams. Might help ?
     
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