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.

Movement of the human foot in 100 pain free individuals and implications for understanding normal fo

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Nov 29, 2014.

  1. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1

    Members do not see these Ads. Sign Up.
    Movement of the human foot in 100 pain free individuals and implications for understanding normal foot function.
    Christopher J Nester, Hannah Jarvis, Richard K Jones, Peter D Bowden and Anmin Liu
    Journal of Foot and Ankle Research 2014, 7:51 doi:10.1186/s13047-014-0051-8
     
  2. Will read the full text later, just wonder why use "normal" in the title.

    Personally getting away from normal is still an important step podiatrist biomechanics needs to make.

    However the paper looks very interesting re joint coupling etc
     
  3. efuller

    efuller MVP

    We should also question the premise that we need to understand motion to treat foot pathology. I will bet that force in anatomical structures will be more important than motion for predicting pathology. However, Im looking forward to readng the paper to see if there is some useful information.

    Eric
     
  4. David Smith

    David Smith Well-Known Member

    what is (joint) coupling in terms of foot motion?
     
  5. Since this work seems to be primarilly derived from Hannah Jarvis's PhD, I went back to her thesis to see how she defined "coupling". The word "coupling" appears twelve times, these are probably the closest to a definition she provides:

    "The inter-dependent function of the joints of the foot play an integral role in its function during the gait cycle. Some (Wolf et al 2008, Pohl et al 2006, Eslami et al 2007, Huson 1991 and Dierks and Davis 2007) have described this as coupling mechanisms. "

    "Root et al (1971, 1977) described the movement of the joints of the foot independently from each other. However, the results from some (Huson 2000, Huson 1991, Wolf et al 2008, Pohl et al 2006, Lundgren et al 2007, Nester et al 2006) have demonstrated that the function of the foot is complex and there is inter-segmental co- ordination or coupling mechanisms between the joints of the foot.."
     
  6. Dennis Kiper

    Dennis Kiper Well-Known Member

    I will bet that force in anatomical structures will be more important than motion for predicting pathology

    Isn't force a function of its motion?

    It would be nice to “predict” a pathology, but normal over pronation forces and the variety of complex factors that contribute to pathology can be minimized and possibly prevented with a functionally accurate orthotic. Then there would be no need to predict.
     
  7. efuller

    efuller MVP

    Not necessarily. Put your hand on a table. Place a feather on top. Remove feather and place a 20 lb weight on top of your hand. The motion is the same in both cases but the force is different.

    A foot example occurs when the STJ has reached its end of range of motion in the direction of pronation. At this point the lateral process of the talus hits the floor of the sinus tarsi. You can be maximally pronated with very little force between the talus and calcaneus or you can be maximally pronated with a lot of force. In both cases the STJ is maximally pronated, but the amount of force is entirely different.

    Is accuracy in orthotics when the foot lands entirely on top of the orthotic?

    The patient probably cares whether or not we can predict pathology. If predict correctly that they won't have pain they won't need an orthotic. If we correctly predict what would occur without an orthotic, we will be able to give the patient the orthtoic with the modifications that will prevent the patients pathology. Different feet will have different pathology. A single type of orthotic will not be good for all feet.

    Eric
     
  8. Dennis Kiper

    Dennis Kiper Well-Known Member

    You can be maximally pronated with very little force between the talus and calcaneus or you can be maximally pronated with a lot of force. In both cases the STJ is maximally pronated, but the amount of force is entirely different.


    Is this documented or are you guessing? How do you measure these forces? Are they in pounds or kilograms?

    Is accuracy in orthotics when the foot lands entirely on top of the orthotic?

    If you mean mid stance, No, accuracy in biomechanical stability must also be accurate at the precise moment of heel off, otherwise you have immediate subluxation and instability at the propulsive stage. In a traditional orthotic technology, one loses peak efficiency at this moment in time. This results in pathological forces, (over time) thoughout the lower extremity when the foot should demonstrate “dynamic” stability.





    we will be able to give the patient the orthtoic with the modifications that will prevent the patients pathology.

    Clinical results between generic and custom orthotics is both poor and unpredictable, so when you're utilizing traditional orthotic technology, you're predictability is probably 50/50.

    Different feet will have different pathology.

    This is true, however with the exception of anomolous biomechanics, one could use the same orthotic
    (size, not withstanding) but a different Rx for the individual foot.
     
  9. efuller

    efuller MVP

    I don't believe that it has been documented. It could easily be measured. It can also be felt. You would need several wedges of different degrees. Start with the smallest wedge under the lateral forefoot. Then stand on the next biggest wedge. As you increase the size of a wedge you will reach a point where there is no more foot eversion available. As you increase wedge size beyond this point increasing compression can be felt in the sinus tarsi. Using wedges may not give the proper sense of what is going on. this may give you the sense that it is attempted motion that is causing the increased compression Instead of "increasing motion" what you have to do is increase pronation moment. This is done by shifting the center of pressure under the foot more lateral.

    Forces are measured in Newtons in the metric system. From F=ma Newtons are equal to mass x acceleration. Kilograms x meters per second squared Kg/m/sec^2

    In the English system pounds is both the unit of mass and force, which is confusing.





    That paragraph raises more questions. What is biomechanical stability. How do you measure accuracy of biomechanical stability.

    I've seen a definition of subluxation and it is kind of a nebulous term. What joint are you saying subluxes and what direction?

    How are you defining efficiency and how do you know traditional orthotics don't have peak efficiency. How does being inefficient cause pathologic forces. In what anatomical structures do the pathologic forces occur?

    Is the success rate you quote for traditional orthotics published, or are you just guessing?

    Regards,
    Eric
     
  10. Dennis Kiper

    Dennis Kiper Well-Known Member

    What is biomechanical stability. How do you measure accuracy of biomechanical stability.

    Biomechanical stability is the “equal” diffusion of GRF, such that it is visible in the gait pattern. It can be seen and measured with a gait analysis system—see http://drkiper.com/animation.html


    I've seen a definition of subluxation and it is kind of a nebulous term. What joint are you saying subluxes and what direction?

    I defined this on another thread we're communicating on. Subluxation can occur at any joint or group of joints, generally in the direction of pronation.

    How are you defining efficiency and how do you know traditional orthotics don't have peak efficiency.

    I'm sure some traditional orthotics do produce peak efficiency. But, it's not consistent, because it's not quantifiable and inconsistent between practitioners.


    How does being inefficient cause pathologic forces. In what anatomical structures do the pathologic forces occur?

    Pathological forces always exist throughout the lower extremity. You cannot eliminate them. In my opinion, you can only minimize them.


    Is the success rate you quote for traditional orthotics published, or are you just guessing?

    I'm guessing based on published clinical results.
     
  11. davidh

    davidh Podiatry Arena Veteran

    From a PhD work you say?
    I examined available motion in over 100 ankle joint complex subjects, and they only gave me an MSc :D.

    The title is a tad misleading - I haven't read the paper but assume the study was carried out on a hard, flat surface (treadmill or somesuch). We normal subjects have far more available movement in our feet and ankles than is required merely to walk on hard, flat surfaces.
     
Loading...

Share This Page