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Elite athletes and foot biomechanics

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Ian Linane, May 30, 2005.

  1. Ian Linane

    Ian Linane Well-Known Member


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    <ADMIN NOTE> This thread has been split off from the Nike Barefoot Running Shoe thread

    "Elite athletes, who have naturally good bio-mechanics"


    Having no experience of this device I am curious as to the following:

    1. Could someone explain the reasoning behind this assumption of elite atheletes having good biomechanic

    2. Whilst the barefoot running is mimicked ( so as to be natural) could they explain how natural terrain is mimicked by the shoe so that the foot then functions "naturally"

    Ian
     
    Last edited by a moderator: May 31, 2005
  2. Craig Payne

    Craig Payne Moderator

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    Its probably a good assumption - it keeps coming up. I was on a panel at a recent sports med conference with the head of Australia's elite sports acadamc (Peter Fricker) and he pretty much said the same thing.

    The assumption is based on the princple that if you are a elite athlete, then as you can run fast you must have very efficient biomechanics ---- it is possible that the efficient biomechanics is also the same as the biomechanics that could be somewhat protective from injury. Also if you suffer from less injuries --> train more --> become elite athlete.

    There will always be exceptions to this assumption.
     
    Last edited: May 31, 2005
  3. Ian Linane

    Ian Linane Well-Known Member

    Hi Craig

    Thanks for the reply and I can recognise the points made.

    I suppose the question is really one of what are they implying by "good biomechanics"

    1. Is it the implication that these elite athteletes have a foot type that is as near the "ideal" as possible?

    2. Do these elite not have the issue of rigid plantarflexed 1st rays or pes cavus type feet?

    What is it that is good about their mechanics and are they uniformly the same, or, have they used their intense, specialised training to overcome a foot type that is not designed for unnatural terrain?

    Ian
     
  4. Craig Payne

    Craig Payne Moderator

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    Thats the $64 000 queston --- look at some elite athletes, for eg Cathy Freeman, who from what I can see have what we would consider "shocking" biomechanics ... but she can run fast enough to win gold at 400 metres. Look at the "severe" asymmetry in the gait of some of the elite african runners. ... there are many whose biomechaincs are not consistent with our "verticality" model, but can run fast.

    I think the answer lies in something like Beno Nigg's preferred motion pathway model .... while these people might not match the "verticality" model of gait, they are functioning within their preferred pathway. Any attempts to move them outside that pathway with foot orthoses may have disastrous consequences.
     
  5. Ian Linane

    Ian Linane Well-Known Member

    Hi Craig

    Thanks for the reply. I find Nigg's concepts insightful and helpful. Not just for the mechanics ( my limited understanding allowing) but because it allows for body "intelligence". Whilst this can be a term applied to muscular intelligence I would also want to argue for a level of "information" communication in the energy system of the body that gives rapid feed back. (Something used in certain areas of psychology treatment for rapid, almost immediate, resolution of trauma information). Remove the "bio" from mechanics and we simply have mechanics applied to a living organism. Apply "bio" and we can remind ourselves that the body functions as a living, reactive beast with various levels of communication and did do long before modern surfaces.

    Maybe I'm suggesting things way out of field here. :eek:

    Ian
     
  6. Craig Payne

    Craig Payne Moderator

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    The big challenge now is, if Nigg's model is to have merit, is how do you determine the preferred pathway for each individual, let alone use orthoses to move those who are functioning outside their preferred pathway back into it with foot orthoses (or accidently move people outside it with the wrong foot orthoses for that individual, which i am sure we do a lot of :eek: )

    ... have been giving this a lot of thought and will pursue it at some stage .... but it is most likely, that the preferred pathway for an individual is that pathway in which muscle activity is reduced to a minimum at any given velocity for a motion. (this model also has implications for getting people to run faster with foot orthoses --- ie performance enhancement).

    This is where we need to go:
    1. Use of EMG and different foot orthoses in different foot types to determine what combination of type of foot orthoses in which type of foot can achieve a "global" reduction in mucsle activity ---- assume that each individual that needs foot orthoses does have an optimal pathway they can be moved towards to reduce muscle activity --> more efficient function and maybe performance enhancement

    2. Once this is determined, then need to move on to symptoms --- ie if the foot orthoses do reduce muscle activity to lowest "global" level, do those with symptoms actually get better (and vice versa)

    3. Then need a proper RCT to test it

    3.5 Probably could squeeze a study in here to test the perfromance enhancement side of the equation

    4. Then need to determine if any simple clinical tests can be somewhat predictive of the "global" reduction in EMG, so clinicians can apply it on a routine basis for those with injury when foot orthoses are indicated (important point!)

    5. Then needs a proper RCT to test (4)

    ..... God put on this earth to accomplish a certain number of things ... right now I am so far behind I will never die.
     
  7. Cameron

    Cameron Well-Known Member

    Ian and Craig

    Much can be revealed in the etymology of terms. Biomechanics originally meant the body system (complete) with no specific reference to locomotion perse. It would be misleading to seek meaning in the term from a 21 st century perspective without knowing the history that surrounds the word.

    By the mid 50s onwards bioengineering described much of what we would now accept as biomechanics. Podiatric biomechanics in the 70s was a hybrid and quasi-science, which piggybacked onto the more scientific, bioengineering. Somewhere between now and then the two terms merged in the common lexicon and by association podiatric biomechanics became common vernacular with sporty people but it still based on a tautology.

    Ian wrote
    >I suppose the question is really one of what are they implying by "good biomechanics"

    Biomechanics is good and describes optimal efficiency in the locomotor system. Pathomechanics is the term, which we do not use often enough to describe abnormal compensations.

    > Is it the implication that these elite athletes have a foot type that is as near the "ideal" as possible?

    Part of this mistaken assumption is based on reductionist logic i.e. there is a an ideal foot and everyone can have this state of perfection by some means or another

    This is based on the philiosophical Judo-Christian belief that we (men) are made in the image of God and therefore the body is perfect. In reality, the body is far from perfect and commonality describes wide variation in anthropometry. This truism conflicts with another philosophical theorem that underpins the medical model. The infrastructure of which is based on imperfect people can be made perfect by (medical) intervention e.g. orthopaedics is a good example, the word means to make straight.

    'There are more things in heavan and earth, Horatio, than are dreamt of in
    your philosophy. Shakespeare

    Nigg and Root's Theory are two excellent examples of normalising by reducing the phenomena to a simple model which allows clinicians (analysts) to apply current therapies and address that which is know to respond to the particular analysis. This of course is a gross oversimplification of the human condition but may represent the best we have at the time. Our understanding and technology limit us.

    Using a reductionist approach means the sum of the parts is never to same as the whole. This is the major flaw in our current approach to health at both a micro and macro levels. For example the priority given to administrative quality control initiatives in public sector health care may detract from actual care of patients but serve well as a more accountable service to clients.

    Back to sport. Probably people start out on the sporting activities to which their bodies are best suited towards. Through time the elite emerge not because they all exhibit the ideal model (that is rare) but through hard work strength and endurance, much of which will result in RSI and pathomechanical changes with the inevitable consequences for some.

    As a phenomenon foot orthoses (tilts , lifts or wedges) reduce TRM and preserve end of range motion enforcing rest from repetitive stresses which would account, in some cases, for reduced symptoms.

    Many years ago I did intend to build a gait laboratory which looked specifically at standard physiological values for testing elite athletes. The assumption being if the effect of FOs translated into more efficient locomotion (verified by time trials etc) then that would affect breathing. Gas exchange and blood levels are easier to measure and more reliable than pressure plate analysis. Sadly I nerve quite got to complete the project which was quickly reverted to the same old same old.

    I spend sometime at Strathclyde University at the Bioengineering Unit and came away with one lasting piece of information, 'each heel strike is an unique event.'

    Well worth remembering


    What say you?

    Cameron
     
  8. First of all, in order to have an elite athlete, one needs more than just good feet. Being an elite athlete is multifactorial.

    One must have a body structure and muscle type that is well-suited to that particular sport's specific physical demands (i.e. a 250 pound athlete with a high percentage of fast twitch muscle fibers and excellent upper body strength will have little chance of becoming an elite marathon runner but may have a very good chance of being an elite athlete in American football.) One must also be healthy and relatively free from major diseases or pathological processes that affect performance. And one must have the psychological profile to train long hours at one sport for many years.

    Therefore, to focus only on the foot is a little "podiatric-centric" when looking at what makes an elite athlete. However, if you are speaking of long distance running (my competitive sport for many years), then in general, I have noticed that the feet of these athletes are generally more "normal" than their non-athletic peers. I have long felt that this is due to a process of selection that the young athlete makes at a young age in that they receive positive reinforcement when they perform well at a certain sport, tending to make them gravitate toward those sports that they perform well at, and tending to make them stay with these sports as long as they don't get injured often while training and performing in these sports. In addition, possibly long distance runners develop more normal gait simply due to their increased muscle strength from their running activities and relatively low body weight/leg muscle strength ratio.

    In my podiatry school class of about 125 students (CCPM Class of 1983), five of us in our freshman year had run the Boston marathon competitively, and were still training about 50 miles or more per week. When we did gait examinations on all our 125 classmantes over the next few years of school, who do you think had the most "normal" gait examinations?.... the long distance runners. I think that better structure of the whole lower extremity (not just the feet) are critical in an individiual to allowing the amount of miles to become a competitive distance runner and that as a result of the training, the foot and leg strength are increased significantly, thus improving gait function.

    Elite downhill skiers (Alpine skiers) often do have "rigid plantarflexed first rays" but this is rarely found in elite long distance runners. Foot type, flexibility and structure will tend to influence how that foot will perform in a given sport depending on the specific physical demands of that sport. In downhill skiing, good medial edge pressure is needed from the foot inside the boot that is then transferred to the binding and the ski. Good medial edge pressure is much easier to achieve in a foot that has a "rigid plantarflexed first ray" than a foot that has a flexible pes planus with a first ray with decreased dorsiflexion stiffness. However, this "rigid plantarflexed first ray" will tend to also decrease shock absorbing ability in long distance runners and will tend to cause shock (impact) related pathologies in the runner with these type of feet. Most good distance runners have slightly lower than normal arch height.

    Good sports-performance discussion. Let's have more of these!
     
  9. Craig and Ian:

    Good discussion on sports biomechanics. While I am a great admirer of Benno Nigg, have lectured with him a few times, and visited his lab in Calgary, I have a few problems with his theory of "preferred motion pathway". Preferred motion pathway makes the assumption that the individual will choose a certain kinematic pattern of limb motions during gait that is most efficient for them. If a mechanical intervention supports the preferred motion pathway, then muscle activity will be reduced and this will theoretically correspond to improved comfort.

    However, the preferred kinematic pattern will be altered even by slight foot orthosis adjustments, especially the sagittal plane of motion. Howard Dananberg has shown relative large changes in kinematic patterns of the hip with foot orthoses using his specific corrections. I also see these relatively large sagittal plane changes in patients once the best orthoses are made for specific patients. The question then becomes, if Nigg's "preferred motion pathway" theory is accurate, then what is the preferred motion pathway for these patients, the motion pathway with the orthoses or the motion pathway without the orthoses?? Or does the "preferred motion pathway" change with each orthosis intervention and how do will we ever be able to test this theory if it does change with each orthosis intervention?

    Research conducted recently by Mundermann et al (with Nigg) on 21 runners showed changes in kinematics (i.e. reduced maximum foot eversion and increased maximum foot invesion) with foot orthoses that were made by a podiatrist (Mündermann, A, Nigg BM, Humble, RN, Stefanyshyn, DJ: Foot orthotics affect lower extremity kinematics and kinetics during running. Clin Biomechanics, 18(3):254-262, 2003). If orthoses cause a significant change in kinematics, as these researchers have shown with custom foot orthoses, what then is the "preferred motion pathway" for these runners, that motion pathway with or that motion pathway without foot orthoses??

    Maybe I am splitting hairs here a little in my analysis of Nigg's "preferred motion pathway" theory since I think that it has merit and think that it is an interesting idea. However, I also think that it is more likely that the individual will self-select their kinematic pattern based on a number of factors including mechanical economy of the locomotion pattern, emotional state of the individual, injury avoidance and pain avoidance, and not just have one "preferred motion pathway". I believe individuals will also choose a multitude of other styles of kinematic patterns of locomotion depending on the magnitudes, locations and temporal patterns of ground reaction force (GRF) acting on the plantar foot (e.g. from a change in shoes or foot orthoses). These changes in GRF on the plantar foot will cause the individual's central and peripheral nervous system to choose the particular kinematic pattern that is most efficient mechanically for them for that set of specific GRFs. Even though these ideas may be similar in concept to Nigg's preferred motion pathway theory, the observations I have made on the patients I have treated with foot orthoses and the many experimental trials of paddings placed on patients' and students' feet over the past 20+ years seem to indicate that the "preferred motion pathway" theory may explain many observations, but think it certainly needs some significant refinement before it explains all of what we see in the clinical world of foot and lower extremity biomechanics.
     
  10. Ian Linane

    Ian Linane Well-Known Member

    Hi kevin, Craig and Cameron.

    Thanks for the replies.

    A number of questions arise for me here ( no doubt explored already by others).

    1. If the "normal" foot is the one most suited to distance running, probably upon an unnatural surface and shod, is this same foot as suitable for running upon more natural undulating type surfaces barefoot (when muscle function and joint positioning may well need different actions). Or, could it be argued that a foot that allows greater pronation ranges and has a greater amount of FF Supinatus may be more suited for this? So the foot type could be classed a "suitable" (not the term normal)to the type of terrain and / or type of function.

    2. Taking the view of prefered pathway then it seems to make sense that one foot type person would be more suited to a particular sport ( accepting all the other physiological issues). But are we not simply recognising here that this could reflect the idea that many foot types are a variation (not of normal, I am not convinced we have yet or can ever determine what this is),
    simply different to each other?

    Ian (well over my head in all this ;) )
     
  11. davidh

    davidh Podiatry Arena Veteran

    See?
    Great minds do think alike!
    Like Cameron I spent some time at a Bioengineering unit (mine was in Durham), and one of the ideas I toyed with was measuring gas exchange in subjects with and without FO's.

    I ended up doing a different research project too :)

    regards,
    davidh
     
  12. Craig Payne

    Craig Payne Moderator

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    We have toyed with this and unfortunately the natural variability in these respiratory parameters is so great the chances of finding differences with subtle interventions like foot orthoses is not good.
     
    Last edited by a moderator: Jul 15, 2005
  13. Cameron

    Cameron Well-Known Member

    Sportsnetizens

    Anything up to middle distance running is a modified gait cycle similar to normal pedestrian activity and involves a heel strike. One you are into Middle distance activities then the heel strike is knocked out. These means middle distance runners would tend in the main to have ankle equinus type feet. (now there are exceptions). This physique would be less able to cope with the rigours of long distance running because of the stretch on the TA. (again there are exceptions to prove this rule)

    I ran half marathons, fool that I am, and was always staggered at the flat feet of many of the runners. To be truthful I just beat the stragglers so were more than likely to not be in the elite class. I had to stop wearing my podiatry T-shirt because other competitors would stop me and ask for advice :)

    2. Taking the view of preferred pathway then it seems to make sense that one-foot type person would be more suited to a particular sport (accepting all the other physiological issues). But are we not simply recognising here that this could reflect the idea that many foot types are a variation (not of normal, I am not convinced we have yet or can ever determine what this is), simply different to each other?

    Taken at its simplest level and to illustrate a point.

    I attended a surgery lecture once (that was enough) and the surgeon was talking about levels of amputation to an audience of prosthetists. Apart from the obvious factors such as blood supply etc, he articulated one concern was the most appropriate prostheses. In many instances with feet he proffered it was easier to amputate at the ankle because the level of sophistication in foot prosthetics was such as to make it easier for healing and rehabilitation.

    What I think he was saying (in context with this discussion) was it really does not matter about the foot provided it can land efficiently, act as pedestal, before forming a lever to push off and continue to repeat this, ad infinitum under modifying circumstances.

    The quirks of foot mechanics are minor in the overall achievement of efficient locomotion. Now we can argue against this but in truth provided you have the physiological and psychological capacity to overcome the outcomes of sustained compensations to compete, you might find yourself in the elite squad of athletes. Drugs help, but that is another story.

    Talking of which I did see the same orthopaedist give a lecture to podiatrists and he said the level of foot amputation has been determined by the sterling work of podiatrist and all things considered I prefer to recommend a midtarsal procedure.
    A little selected editing for a niche audience


    Dave and Craig

    Good to know I share the same frame of thought as you lads. My plans were circa 1992 so I claim originality. But to be serious trying to convince colleagues we should be looking at physiology and not just kinetics and kinematics was rather like talking in tongues. Craig is quite right, as we found out, in the NZ lab the changes were undetectable but we had only pretty unsophisticated equipment then and it seems with time and more reliable instrumentation the values are still unmeasurable. Later I tried to link analysis of the determinants of gait with foot function as part of orthotic checkout but our equipment was very limited.

    All of which has left me thinking the compensations of feet are lost in the chain of events within the multi articulator skeleton and hence do no seem to register on the wider characteristics that are measurable.

    Our professional anecdotal experiences are incredibly valuable and appreciated by those who benefit from podiatric intervention but trying to explain this quantitatively is yet beyond our ken.

    Cheers
    Cameron
     
  14. davidh

    davidh Podiatry Arena Veteran

    Cameron,
    I concede!
    You can have the originality of concept cup :) !

    On the professional anecdote theme, and coming back to, well, natural selection I guess, back in the 70's (before the running boom), most running clubs in that staunch runners haven, the NE of England had about 50 members. Remember this was in the days before kinetic wedges, Dellinger Webs and Nike Equators (to mention a few of the clever shoes and shoe mods which came a little later). Some runners went out in shoes very similar to 30-bob plimsolls. I personally used to run (well, I was young and daft) in a pair of indoor football trainers.

    Come the running boom suddenly everyone wanted to be a runner, and club memberships rose into the hundreds.
    Injuries were rife.
    But once things settled down the clubs lost many of their new members, and reverted, in many cases back to something approaching their original size.
    Chester-le-St and Silksworth were two of the clubs I worked with, but this happened all over the NE, and presumably the UK.

    So presumably those who were built for running ran, and the others were weeded out by injury or poor performace and went off to do other things.

    Regards,
    davidh
     
  15. Cameron

    Cameron Well-Known Member

    David

    > back in the 70's (before the running boom),......Remember this was in the days before kinetic wedges, Dellinger Webs and Nike Equators (to mention a few of the clever shoes and shoe mods which came a little later).

    tsk, tsk, what about contra lateral wedges, like nail braces rarely spoken off in other than hushed whispers, around Winsor Terrace but were about none the less. O T Vincent was chiropodist in Edinburgh and he was writing about podiatric biomechanics in the late sixites

    You are right on the sport shoes which became trendy during the 70s and that was to meet the demand from a keep fit culture. When I did some research into soccer boots a while ago there was a similar flurry there as the old boot replaced the soccer slipper. I blame England winning the World Cup myself, because global audiences with extraordinary marketing potential started the endorsement culture. Like runners companies looked for the market edge by incorporating a new and improved approach which for soocer boots by the eighties included anti-pronaters. Now there is a body of reasearch which has shown injuries to soccer players increased during this time. Very interesting.

    > So presumably those who were built for running ran, and the others were
    weeded out by injury or poor performace and went off to do other
    things.

    That would my understanding too.

    Cheers
    Cameron
     
  16. David, Cameron, Craig:

    Measuring oxygen uptake of an individual during steady-state exercise has been a standard technique for measuring metabolic efficiency for many years. When I was an undergraduate at UC Davis in the late 1970's, I was a research subject for two treadmill running-oxygen uptake experiments plus I helped out with research at their Human Performance Lab along with taking graduate courses in Exercise Physiology.

    It is no more difficult to measure oxygen uptake in walking, biking or running than to do any type of experiment, if you have the proper facilities, proper equipment and trained personnel. There have been plenty of studies done on oxygen uptake using different experimental conditions to test metabolic efficiency of running over at least the past 30 years. One such study done by some of my friends from my UC Davis days (Catlin, M.J., and R.H. Dressendorfer. Effect of shoe weight on the energy cost of running. Medicine and Science in Sports. 11: 80, 1979), showed a significant increase in oxygen uptake with small masses attached to the running shoes of runners.

    If you are trying to show an improvement in metabolic efficiency with running with orthoses, then it is not so much a problem of sensitivity of the equipment but rather that the process of adding any mass to the shoe will significantly increase oxygen uptake as noted also in the study below:
    Oxygen consumption has been commonly used in many studies of more significant gait pathologies such from spinal cord lesions and other neuromuscular diseases. However, I think that the efficiency changes in walking with foot orthoses may be so small, and may be negated by the added weight of the orthosis, that most researchers have found other research methods to be more effective (i.e. kinematics and kinetics) in analyzing the effects of foot orthoses on human locomotion.
     
  17. davidh

    davidh Podiatry Arena Veteran

    I remember contra-lateral wedges - made some at Windsor Terrace too :) . Couldn't figure out what they did though :confused:

    The problem as I remember it was that whilst Arthur was keen to look at new ideas, they didn't fit in with established orthopaedic principles at that time (like "the foot is a tripod") which Mr McRae was fond of teaching.

    It took me a while (read years!) after qualifying to get my head around the basic mechanics of foot function............................

    regards,
    david
     
  18. Cameron

    Cameron Well-Known Member

    You will need to take the trophy Kevin.

    In NZ we were playing around with Labview and microcomuters with some sports testing equipment nothing too sophisticated but my slant was definately towards kinesiology at the time inspired it has to be said by many papers available from physical therapy and rehabilitation science.

    remember contra-lateral wedges - made some at Windsor Terrace too . Couldn't figure out what they did though

    Medial heel post and lateral forefoot post, sound familiar? These were planar controls, pre the Root orthoses.

    The problem as I remember it was that whilst Arthur was keen to look at new ideas, they didn't fit in with established orthopaedic principles at that time (like "the foot is a tripod") which Mr McRae was fond of teaching.

    It took me a while (read years!) after qualifying to get my head around the basic mechanics of foot function............................

    The skewed foot.

    I am doing my Lambranudie exercises as we speak.
     
  19. pgcarter

    pgcarter Well-Known Member

    Having thought about these things a bit I think that a given body will be running different selection parameters about it's preffered motion pathway depending on whats going on....as Kevin said...loads of overlays here.
    But I do think when people move in unconscious ways with no particular goal in mind they probably begin to do something like this "preffered pathway" or efficient pattern for that body.....but the pattern will change with age and will be contributed to by the quality and range of motion available at almost every joint in the body and by the length and mass of every segment....all these things create torques around our mid line and will influence the symmetry and pattern of our motion...and the metabolic cost.

    Way too many variables to really get my head around.

    But I try..based on each person being different rather than the same as any "pattern" or norm.

    Regards Phill Carter
     
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