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Exploring Turvey's paper on Action and perception at the level of synergies

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Mart, May 12, 2008.

  1. Mart

    Mart Well-Known Member


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    Hi

    I have attatched the file as starting point for some discussion around the limitations of our simplified mecanical approach to trying to understand foot function.

    I have only skim read this so far but I get the impression it may give us a "playing field" to run around on; this is a heavy duty paper but with a bit of mutual support perhaps get past the jargon and clarify some ideas which several of us seem intersted in but lack clear definition of.

    cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     

    Attached Files:

  2. Mart

    Mart Well-Known Member

    Because this paper draws from a knowledge base which pushes me beyond my limits I feel that to get reasonable value from studying it I may have to accept some incomplete understanding or get some help using analogues.

    To get this started I wanted to see if anyone cares to comment on this paragraph (top of p658).


    Bernstein’s functional hierarchy, the level responsible for forming synergies
    of large muscle groups and different patterns of locomotion is referred to as the level
    of muscular–articular links or synergies. The shape of this level is defined by the central
    problem of movement control and coordination: The problem of degrees of freedom – the
    problem of how to compress the movement system’s state space of very many dimensions
    into a control space of very few dimensions. This compression is the expertise of the level
    of muscular–articular links or synergies. The coherence, harmony and precision timing of
    rhythmic limb movements and speech movements typify the level’s special expertise.

    First of all to define some terms

    http://en.wikipedia.org/wiki/State_space_(controls)

    http://en.wikipedia.org/wiki/Degrees_of_freedom_(mechanics)

    This paragraph represents purpose of the entire paper as I see it. Although I may be stating the obvious I just want to make sure there is some agreement about what this means.

    One approach to testing an understanding of an idea is to use different words to indicate meaning so here’s my take trying to avoid highly technical jargon but not lose too much definition ;

    “It may be possible to understand the function of a musculoskeletal system,( in our case the foot or lower limb), at a level in which the enormous apparent complexity of all it’s components possible actions are constrained, so that the control of the combined function of the components may be seen in a simpler, ordered, predicable and coherent way.”

    Please feel free to attack this constructively.

    Cheers

    Martin

    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    Phone [204] 837 FOOT (3668)
    Fax [204] 774 9918
    www.winnipegfootclinic.com
     
    Last edited: May 13, 2008
  3. kevin miller

    kevin miller Active Member

    The Turvey Paper on Synergy.

    Mart, If you would be so kind as to attach the paper back to this. I think the topic was pulled becasue we did not respond. The papaer was very difficult to read and I needed a day. That said, I have some comments and a very pleased to have had the opportunity to read the paper. I see what you mean when you said you would like to see some common vocabulary. What Turvey is saying is practically a mimic of what I have been harping on for the last few years. It is well worth the effort for anyone who wants to understand how the entire body works together. With that, my comments:


    Martin,
    You are correct; this is a very difficult paper to read. However, it is very exciting to read someone else publishing the same ideas I have. I have sent a copy of this to Dr. Steven Levin, the orthopedic surgeon who studies Tensegrity theory. I think this will be very close to what he says as, well but for myself it is very gratifying to see that someone else sees the human body the same way. I am only on page 667 and already I can see where this paper is headed. If I may be so bold, allow me to use Turvey's words and translate them into my own.
    Turvey suggests that the hierarchal view of anatomy is not accurate. This is equivalent to my saying that there are tensile units, compressive units, and articular cartilage which bridge the gap between two, and that all of these structures are equal and in contact with one another. His statements on synergy, agonist antagonist and stabilizer distinction are equivalent to my saying that synergy in muscle action is not necessarily the same as the standard definition of synergistic muscles. When Turvey says that "……..muscles act on multiple limb segments or about multiple axes of rotation, the division into agonist, antagonist, and stabilizer is not an anatomical given but a function of joint angles, lengths of the links, moment arms, and force directions." He might as well be saying "normal synergistic function of compressive and tensile structures is dependent upon constant interplay and transfer force between each structure."
    I especially like the section 1.2 .2 rapid remote adjustments. Here Turvey says that stability is evident in resistance of the cooperative elements to perturbation. I would say that the human body evolved with constant perturbation and that while this perturbation seems to put a stress upon the system, the system has really evolved a unique way of harnessing the perturbation for its own purposes. The most grand of these would be the body’s oscillation in the gravitational field described by Gracovetsky. As the Center of mass elevates in the gravitational field it stores potential energy which is released at heel contact, providing an impulse which travels back through the synergistic tissue mass providing energy for spinal rotation which in turn drives gait through the pelvis. Oddly, perturbation is positive while lack thereof is negative. If a person works on a concrete floor day after day after day, he or she is more likely to develop pathomechanics than a farmer who constantly varies his kinetic chain movements.

    A word or two on neurology and then I will stop because this is going to get long-winded very quickly. Turvey refers to the reflex arc as a cycle rather than the classic model. This fit perfectly with what we were discussing just the other day concerning local control of muscles via a mechanoreceptors rather than the upper motor control. If you will recall I said that some of the actions which occur happen faster than it would take an impulse to go from the foot to the brain and back even on a type I a fiber. The only other option is through the spinal cord and local mechanoreceptors. This appears to be precisely what Turvey is saying on page 662. Lastly, Turvey discussed level of synergies from Bernstein’s perspective. He spoke of synergy as having subsets. I have previously described the subsets as including the eyes, the vestibular cochlear system, joint receptors, tensile tissue receptors and contact receptors which function in synergy throughout the body to maintain stability during gait.

    In short Martin, I am in you're debt for bringing this paper to light. Other than Levin's work, I have never found a reference to use as support for my own research.
    Thank you very much,
    Kevin M.
     
  4. Mart

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.

    Hi Kevin

    I think this is unlikely and as far as I can see paper is still available . . . . probably just a system glitch. Good to hear your effusiveness on this paper. Personally I need some time to digest and go away and read around the paper. I started by going and refreshing/learning more about cartilage structure and how this relates to mechanical properties, filling knowledge gaps. I'll post some stuff for others when I get a moment on this. Because at this stage we are considering an abstract notion, it seems important to make sure that every step is logically sound because there is no other way to test it.

    I dismissed some of your notions primarily on the grounds of inconsistences which others also have mentioned, namely the issue of the nature of compressive forces at joints. I am beginning to question my understanding of the relationships between tensile and compressive action in the body as opposed to those of static mechanical structures which are neccesarily a large part of the limitations of simplified modelling of the foot. Things which I dismissed as absurd are starting to seem like possible, that is always an exciting feeling but I am cautious that it may simply be confusion!

    Look forward to seeing where this might lead, you have already thought about this more than me, I have some catching up to do.

    cheers

    Martin

    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  5. kevin miller

    kevin miller Active Member

    Martin,

    If you grasp the Turvey paper, you are NOT confused. It is a difficult and wordy way to say the same things I have been saying....oh, and with a different vocabulary as well. There is nothing that he says or that Steven Levin, Ingber, or myself mention that does not have basic science holding it up. I truly believe that two things have turned people off. 1) odd sounding vocabulary or description (like tensile units and compressive units). 2) It is something totally new that does not even mention most of what they spent their education learning. I don't know how to get around thins, but a lot of people are certainly missing out.

    Kevin
     
  6. Mart

    Mart Well-Known Member

    Kevin

    I love your enthusiasm but not knowing you, at this stage I could also interpret your reaction as intoxicated (by ideas), and I say this with respect. I am a long way off grasping this paper properly and need to approach this step by step. Looking forward to doing this, though I have found that it can be tough to keep my momentum focused because something else interesting comes along. I think this is an attribute which separates true researchers from dabblers, it takes commitment to see things right through and I tend towards the later.

    Cheers

    Martin

    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
    Last edited: May 14, 2008
  7. David Smith

    David Smith Well-Known Member

    Kevin and Mart

    I've had a quick read of about half this paper and astoundingly enough I will say the same a Kevin M. It totaly agrees with what I have previoulsy been taught and have written about.

    From the perspective of Applied biomechanics evaluated in 3D the synergism of muscles and joints it is the whole basis of analysis and modeling. 2D modelling and analysis is very nice for the 'simple' explaination of a certain movement of interest but once you go into the obliquity of 3D, the synergism and redundancy of the dynamic musculo-skeletal system becomes very apparent. This is terminolgy that I am very familiar with and have tried to explain these concepts before on the forums.

    So in other words the joint of interest may have many degrees of freedom IE it has the ability to be able to move in any direction and not just in the orthoganal global refrerence frame of the lab. There are 6 degrees of freedom 3 of rotation and 3 of translation within any stated reference frame. The number of reference frames could be infinite and in the body are usually imagined to be those of the local frame (loacal to the limb or joint of interest) at any time of interest thru the motion or activity of interest. If we speak in clinical terms of flexion extension etc then a muscle may hay have a desired objective action of flexion. However it will also externally rotate and abduct. In which case other muscles must compensate for this to achieve the desired action of pure flexion. These muscles also have unwantd actions and if they cross another joint they will start a cascade of reactive actions to correct and compensate for any unwanted action there. Clearly this synergistic action of multiple muscles may progress thruough out the entire body and so therefore a single desired action may recruit many groups of apparently unrelated muscles. This principle will also apply to any tissue ie ligaments, fascia, bones and skin that can cause a synergistic reaction to produce the desired action. In this way the need for the recruitment of tissues distal from the desired action to support that action is well known in biomechanics. However it is not easily modeled and models, even sophisticated computer generated finite element models of activities of interest are inevitably simplified in some way.

    Therefore if the architectural rules of Tensegrity structures are allowed to be violated insofar as that in Bio Tensegrity there is a system of interdependant tension and compression units that can be defined as a single operating unit dependant on the pertubation of the system at the point of interest and at the same time there can sometimes be cases of continuous compression then there is indeed Bio tensegrity. As biomechanists we have known that as something different and probably have not attributed a single name to this holisto-synergistic operating principle.

    If also now you can say that in fact there is no continuous compression due to the fluid nature of cartilage which renders the system in a state of discontinuous compression then you could define this almost as a true tensegrity structure, which also is not incongruent with normaly accepted biomechanical evaluation.

    The fluid nature of cartilage being that if it is analogous to a ballon then the forces that tend to be compressive on the whole are actually contained by tensile boundaries and therefore the tensile boundaries seperate the compressional struts ie the bones. If the cartilage is analogous to thousands of tiny ballons then we could see a braek down under excessive compression IE bursting of the minor tensile boundaries, until such a state exists that the compressional struts (bones) do touch and result in degenaration of the articular surfaces.

    This would be very close to true tenegrity architecture if you could describe how it is possible for compressional forces at the bone, cartilage interface not to overload the cartilage generally.

    Clearly there is a consideration of definition to be arbitrated and that definition may lie in two seperate conditions.

    1) How far can the perfect model of BioTensegrity be violated and still be allowed

    2) How deep do we go in our investigations into that definition. Do we stop at the macroscopic the microscopic or the atomic level.

    In biomechanics we do not use such ambiguous terms as tonus and would evaluate the material and physiological properties as seperate entities. Those proposing Biotensegrity must be as unambiguous with their definitions and rigorous in their evaluations also.

    Cheers Dave
     
  8. Mart

    Mart Well-Known Member

    Hi Dave

    Nicely put and I recognise that you have articulated very nicely what I have been starting to get a glimpse of. I have not had a chance to read the paper which Kevin Kirby recommended to compare this against yet and would prefere to get a better handle on this one first, it will take me several reads. :good:

    On p662 Turvey created a visual analogy using the mobius band to replace the 2 pronged idea that most of us have regarding control, both in relation to muscular and neurological control. He considers the notion of the reflex arc as flawed and suggests we consider a continual system as a better explaination for what we see.

    My understanding of feedback systems implies that a sensor sends out a signal which causes a reaction at the sensed site which then modifies the sensor etc ... in mind this is a back and forth activity what Turvey describes as afference and efference. I guess this stems from the anatomical structure of the peripheral nervous system, and what Turvey also describes as the faults of the functional classification of muscles opposing groups. Whilst currently I understand the logic of this problem I am unable to see how this might work yet . . . . . but it is an intriguing possibility.

    cheers


    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  9. kevin miller

    kevin miller Active Member

    David, Martin, quite right you guys are!!! Thank you very much for this paper, having it keeps me from looking so much like a nut.

    David, addressing your last hurdles to the tensegrity concept: 1) Biotensegrity cam first, not engineering. we do not need to subscribe to their laws and definitions, they are but a frail imitation of biotensegral systems, so don't worry about the definitions, which brings me to 2) If you peruse the links below, I am sure you will find you answer to how cartilage can transfer all that force without taking on enough to damage it. Remeber my saying tht the body's structures acted in layers of of structrures with multiple actgions? Wait until you see what Ingber has done with cell!!

    http://www.childrenshospital.org/cfapps/research/data_admin/Site97/mainpageS97P0.html
    http://www.childrenshospital.org/research/ingber/

    Kevin M
     
  10. Mart

    Mart Well-Known Member

    What seems to have happened to me in this thread is this;

    Several seeds of ideas have been sown over the past couple of years which hinted at ways to try and understand some my observations which baffled me. A cursory look at the literature using keyword searches has pulled out some papers which seemed relevant and approached the problem from a different realm and from a largely alien knowledge base.

    After studying the paper(s) I realized that I was not going to get a grasp of the ideas in a satisfactory way but continued to feel there was some value in trying to get something from the document(s).

    To make further progress I felt the need to find someone who understood the paper and who I could discuss this in a way that might somehow bridge my knowledge and theirs.

    Having read Turveys paper a few times it falls into this place for me.

    Its a bit like sitting in a room with others who speak a different language which you have a travel dictionary knowedge of, recognising a few words which are recognisable and seem to be making some sense but nothing of real depth.

    On another thread I had a similar experience looking at ways to interpret force/time curves by using Fourier transform to create a dimensionless variable which may have some statistical value looking at inter step variance, a highly mathematical notion. I have recently (completely by chance) met a retired math prof who has agreed to sit down with me and discuss the paper and see if he can be a bridge between our worlds. When I explained my interested he was very fascinated and seemed totally to understand my interest in this, and we immediately latched on to the possible merits and limitations of the notion. If it is productive I’ll post that on the relevant thread.

    I get a sense that we need to do the same with this. There has understandably limited response to this thread so far. I am curious to know if anyone has really grasped the entirety of this paper (not just the implications)? If so I think we might proceed to create a bridge at least between my lack of understanding and an expert on by me pumping out some questions.

    Any takers?

    David has done a great job to date on the general notions of relating the tensegrity issues to the foot/ lower limb, but not sure if he can go further with this paper.


    http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=11271&page=3

    post # 80

    So next best will be to seek some-one out, before doing that I just wanted to see if anyone so far feels up to the task of in depth bridge builder?

    Cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
    Last edited: May 16, 2008
  11. kevin miller

    kevin miller Active Member

    Martin,

    Why dont't you ask the man himself, Dr Steven Levin? He is an orthopod who is retired and runs this site: http://www.biotensegrity.com/

    He will be a little more rigid in his thought, bt I have contacted him and he knows Turvey and is famliar with the paper. In fact, he references the paper on his site.

    Kev
     
  12. Mart

    Mart Well-Known Member



    Hi Kev

    Good idea.

    What I had in mind was trying to define a purpose which narrows down some key points, I was thinking to try Turvey but if you already have some rapport established with Steven Levin that would I would imagine make engagement a little more likely.

    Though it is ideal to try and grasp AMAP on a subject ,as far as this paper is concerned there is too much which is way over my head as for me to chew off in the near future (or even in this life!).

    Perhaps we should limit ourselves at least initially to getting to grips with the issue of joint compressive forces primarily and what the reduction in degrees of freedom may allow us to do, which is usefully different from the established biomechanical model(s) and what its limitations might also be which we would be aware of.

    My key interest is clinical not pure science so from that perspective I am looking for some inherent practical purpose for this.

    I want to give Kevin K's recommended paper a read this weekend to see where that might fit.

    http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=11271&page=2

    #54

    Perhaps we could all do that just to give us a useful reference point.

    How do you feel about David’s synopsis, I don’t have anything I could usefully add to that, is there anything there you feel needs tossing around there?

    As usual time is a factor in progressing, I'll post a small package of stuff on structure, function and adaptation of cartilage over next couple of days to give the thread a leveller at a microscopic level and see if anyone wants to add to that, and keep some momentum going.

    Cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  13. kevin miller

    kevin miller Active Member

    As I have said on numerous occasions, I agree with what David said. I also tried to address his last concern... I don't know if i did to his satisfaction.... but I am on the same page he is on. That is why I think the problem is terminology, not substance.

    As for Dr. Levin, I will give you his e-mail and you can contact him to ask what ever you like. I doubt he will come on here. He has his reasons, which I respect, but he is usually very happy to write to someone asking about Tensegrity. urvey's references to tensegrity starting on 683 are essentially what you will hear from Levin. If you want another perspective, check out those Ingber sites to suggested to David. Turvey writes about his (Ingber's)work as well.

    Kev
     
  14. Stanley

    Stanley Well-Known Member

    Re: The Turvey Paper on Synergy.

    Kevin, I just started reading the paper. It will take me some time to get through it. I have a different read on what Turvey is saying. He is saying that there are some basic movements that are required to be done properly. (For instance the basic movement in all of sports in the Olympic clean), from this movement, there are modfications (called subsets) that are required to develop (to allow for variations of that movement (rotational movement added to an Olympic clean is what allows one to be good at throwing the shot).

    I have summarized what I read below. You know I don’t like wordiness, so I made it short and sweet:

    1.1 We have many muscles that work together to do something
    1.2 Synergy-many muscles working as a unit
    1.2.1 At a ball joint the concept of agonist antagonist is not that simple. There are many degrees of freedom, so they can work together at certain angles and planes.
    1.2.2 Physical cooperativity allow for stability with perturbations
    1.2.3 Since muscles can have many roles, synergistic muscles have different functions
    1.2.4 There are some basic movement patterns that all movement is based upon. There are a few muscles that will be able to perform these movements by themselves.
    1.2.5 Since the muscles can move the joints in all directions, it is the sensory input that will confine the movement. There is a need for this sensory control to be continuous
    1.3 Movement is based on the few basic movements. These movements, even though the individual is fluent in it, require constant sensory feedback from both the proprioceptive and exteroceptive systems.
    2 Tone is a state of muscle preparedness
    2.1 Dexterity is that ability to perform a movement when the environment can perturb the movement
    3 There are many ways that synergistic muscles interact
    3.1 ????
    3.2 At different speeds, the symmetry of gait changes (in fish birds humans quadrupeds and hexapods)

    Regards,

    Stanley
     
  15. Mart

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.

    Hi Stanley

    In as much as I have been able, I have reached a similar interpretation so far.

    Here’s a situation which we could mull over and perhaps test out a little which may reveal if I am seeing things in a similar light to you.

    You are probably familiar with computerized mat matrixes of pressure sensors which are used to collect data of vertical GRF as subjects walk over them, I use one made by Tekscan.

    The calibration method I use involves dividing the sensors into 2 equal sized rectangular areas and using the subjects weight (measured on a different system) to change the resistance of the cells under a single foot, the software computes the necessary relationships between those variables and then displays the results as measured units rather than raw data.

    The algorithm used during the calibration process uses (and this is my logical assumption and may be false) the rate of change of force on each of the contact cells to determine if the calibration is valid. If the rate of change is too rapid or not within a certain period the calibration is rejected and the software asks for the process to be repeated. The action performed to do this involves standing with both feet on top of the mat and touching against a vertical surface within arms reach with a single finger above head height to improve stability. The subject is asked to stand on one foot (heel and forefoot) and then as the operator counts down (3 2 1)transfer their weight onto the other foot whilst raising the dependant foot, at this point the software starts measuring for several seconds and “decides” subsequently if to accept to reject the process.

    Now what (I think) I have noticed is that there is quite a wide range of ability to do this and that those that initially have difficulty and have the calibration rejected do eventually manage to succeed. Being a real life situation it could lend itself to some investigation notwithstanding the software doing what I suggested, the system could be set up to behave this way.

    Now I realize that there are some horrible possible confounding variables at play here, which would need examining before treating this as a more serious measured experiment. As a thought experiment, lets assume that the ability to successfully complete the calibration process requires a certain level of stability and those who fail to meet that level initially change somehow to do so (I think this is what I am seeing).

    Switching sides during stationary standing single limb support represents perturbation of COM which requires the body to perform a series of adjustments to remain upright. If it is true that during the calibration process there is an improvement in performance it is unlikely to come from any significant structural alteration to the subject’s supporting structures, it must come from the coordination process.

    So my question is what might that amount to?

    I have an idea which I have not been able to test and not sure if it could be, without spelling it out yet I thought it would be interetsing to see if anyone might think along the same lines.


    cheers

    Martin

    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  16. Stanley

    Stanley Well-Known Member

    Re: The Turvey Paper on Synergy.

    Mart,

    I would imagine that since you have done nothing to change proprioception or exteroception, then it is the coordination process as you said (specifically the efferents).
    I think the patient has to first bring the COM over the stance foot before he can lift the opposite foot. If the patient does not do this first, it is impossible to stand without falling. After the first failure, the patient lears to move the COM further until he gets it right.

    I hope this answers your question.

    Regards,

    Stanley
     
  17. kevin miller

    kevin miller Active Member

    Mert, Stanley,

    I see where you are coming from and do not deny that Turvey says those things, but I was looking at context. He also either says the following or points us to an author who did:

    • Turvey says that the traditional view of the human body is hierarchal. Problem with this is that “hierarchal” broadly means an organization of successive subsets without implying any relationship among them. In other words the traditional view doesn't necessarily mean that the parts talk to each other.
    • Synergies on the other hand are just the opposite. The DO communicate in some way.
    • He makes the note that synergistic muscles are not equivalent to synergistic in action.
    • I really like his definition of synergy where he says that synergism and physical cooperativity is evident in a systems resistance to perturbation.
    • When perturbed, a physical cooperativity preserves a macroscopic steady-state through systematic adjustments at its atomic level.
    • Where I have said that there must be some local control going on with mechanoreceptors because reaction to curve faster than the nerve signal can travel from the foot to the brain, Turvey says that there is a reflex arc that is virtually a continuous circuit. Neurologically you don't have to do something to cause a response, you have to do something to purterb the circuit. E.g.,If my muscles synergy create stability during gait and I step on a rock, producing instability, I don't have to have a reflex are all the way through my spinal cord because the synergy created by the muscles, fascia, mechanoreceptors, etc. is inherently stable
    • to reiterate the above, the human body is a synergistic mass of tissues which maintain a sort of stasis through a continuous reflex circuitry that monitors stability and makes instantaneous adjustments at the site of perturbation.
    • With reference to tonus: Tonus is a term used to describe the convergence of different properties such as elasticity, viscosity, and muscle reflexes. We use the term tonus to avoid having to break the synergism of properties into its component.
    • The body structure is a layered set of pre stressed tensegrities which are sensing, actuating and providing feedback.
    • The layering is fractile like in that tensegrities occur at the cellular level and progress to the macro level, while structural tensegrities are strictly mechanical in nature, biological tensegrities are represented in an endless cycle of afference and efference. They are a virtual balancing act where any perturbation of the system is acted on to maintain the original stability.

    I'm sure I left something out, but this gets you guys the idea.

    Kev
     
  18. Stanley

    Stanley Well-Known Member

    Kevin,

    If you look at this:

    http://www.anatomytrains.com/uploads/rich_media/AnatomyTrainsOverview.pdf

    on page 170 in the middle of the page, it talks about the fascia transmitting information at the speed of sound.

    Could you comment on this? I am not sure if this is true or not.

    Regards,

    Stanley
     
  19. Mart

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.

    Thanks Stanley

    Your suggestion was my initial explanation for what I noticed too and remains for me the most likely.

    An important detail which I should have mentioned is that the subject gets no feedback to change performance other than that the calibration failed because of excessive sway.

    The other possibility (which maybe related) is the possibility of pre-stress of musculoskeletal units. My level of knowledge is imprecise but my understanding is that mechano-sensor and muscle response time is improved within certain ranges of tension and that the “learning” process may also involve shifting the segment of range used by increasing “tonus” of the system. I estimate that you guys (David and Kevin too) have already thought about this, hence my curiosity, I have some homework to do on this to get better understanding on this subject. If prestress works in the way that I think it might then it is possible that the systemic alteration may be a modulation of tension/compression equilibrium between and within the different components operating.

    As Kevin K already stated as that we are still operating within the world of science fiction. However the appeal of good SF is its plausability, so far I see we are within the realms of plausabity so at least the plot to date is worthy and intersting :).

    I have read the paper which Kevin K recommended; it is a great exploration of the mechanics of foot anatomy. However I feel that this examines a different but connected realm .The mechanics of the foot analysed at the level of moments, GRFs and material properties, gives us a wonderful picture of the limitations and trends of function. I cannot see how it might explain some of the phenomenon we seek to explain.

    cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
    Last edited: May 18, 2008
  20. Mart

    Mart Well-Known Member

    Hi Hev

    We are all getting the same interpretation which is good start.

    In section 5.3 Turvey talks about the horizontal and vertical ways of thinking about the organization of “synergies”. Subsystems working in a linear chain like way, which is definitely the way I have thought of thre MSK system.

    This presents a limitation in performance in being the addition of sensor/ response time events. Also (although he doesn’t say this) the weakest link in a chain for mechanical limits will be the weakest structure. He used the chain visual analogue for this horizontal relationship. Turvey seems to be logically justifying the option for us to move away from this idea, and largely how engineering design problems are solved, to a more orchestral idea, ie information movement, processing and response which is parallel.

    Turvey encourages us to think about a vertical relationship – the 4 legs of a table analogue. So that from a time perspective the components can act in parallel, system performance improves to the fastest or even better coordinated effect of information transmission (nervous system and various sensors), and from the actuator side (and, although I don’t think he says this here either) , the supporting structures (if alive) could possibly do this too.

    This is very akin to the difference between the linear processing of a computer program which is designed around our self conversation analogue, typically a computer is a written sequence of operations with loops which feedback (the chain analogy) . Compare this to the way our brains seem to operate with parallel processing networks which may allow for fast response which may protects us from immediate danger (possibly by having hardwired stereotyped recognition) parallel with a slower more detailed processing of input (you walk down a dark street alone at night and in peripheral vision you see something threatening motion, duck down, heart racing you escape the clutches of your shadow) .

    David already stated the key issue as far as I am concerned and I sense that we are all in agreement on this.




    If possible our task then is to see if there is anyway we can make progress with this by looking for evidence in foot or lower limb function either logically or in real life which is distinct form Turvey’s generalized description of possibility. Away from SF to S fact (or not).

    Now for the hard part.

    If you can give us any hints from your research without jepardising meeting it's requirements that would give us a leg up :).

    Are we really looking at something new or just relabelling pre-existing notions of MSK co-ordination without being aware of it?

    cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  21. kevin miller

    kevin miller Active Member

    I think you are asking if there is anything in my research that looks like what Turvey is describing. Is that Correct? If so, can you be more specific in what you are looking for, or do you want me to expound?

    Kev
     
  22. kevin miller

    kevin miller Active Member

    Stanley,

    I may be wrong, but I think this is clever prose. They are telling the truth, the vibrations do travel at the speed of sound, but through fluid, not air. This is still quite rapid, however, and not to be taken lightly.

    Kev
     
  23. kevin miller

    kevin miller Active Member

    David, Stanley, Mart,

    I was reading an article by Ingber and ran across this quote. I thought it timely since my suggestion to you was that the rigid definition of tensegrity by thoes who follow the engineers is not what we see in nature.....

    "Demonstration of the ability of the tensegrity
    model to explain complex mechanical behaviors in viruses,
    nuclei, cells, tissues, and organs in animals as
    well as in insects and plants has led to a drastic
    reduction in the number of these confrontations. Nevertheless,
    some intransigent critics remain. However,
    their remaining objections are limited in scope and
    largely result, I believe, from an overly concrete definition
    of what tensegrity is and how it can be applied."

    We may be trying to call known biomechanical phenomena " tensegrity" but I believe this is a bit more to it. Never the less, I also think we are essentially on the same page and that Mart is right abou getting a set vocabulary down. Should the first thing be a modified definition of tensegrity? Truth be told, a combination of Turvey, Ingber, Levin, and what we have said about articular cartilage would do it. Thoughts?

    Kev
     
  24. Kevin Miller:

    I guess you decided to start back up again on tensegrity and "biotensegrity" after posting this message just two days ago.

    So what are implying by immediately starting back up on talking about the wonders of tensegrity and "biotensegrity" is that you may talk about it all you want, but I should only join the discussion if I agree with you??

    The definitions of tensegrity are fine as they are. David has done a nice job of listing the experts on tensegrity and what their definition of tensegrity is. However, the assumptions made in "biotensegrity" do not follow the engineering definition. To me, "biotensegrity" seems a lot like the disciplines that tout "improving energy flow" through the body with their "holistic" therapies. The definition of "biotensegrity" is so ambiguous and unclear to be useless, just like the term "improving energy flow", as far as I'm concerned. This "biotensegrity" is a little too unscientific for me for me to take it seriously. Has the Journal of Biomechanics ever had an article or ever mentioned "biotensegrity"? What is so wrong with using engineering principles and Newtonian physics to explain the actions of the human body? Just because it isn't "biotensegrity", whatever that means, using engineering terminology and Newtonian physics works very well for the remainder of the international biomechanics community in explaining the mechanical function of the human body.
     
  25. Mart

    Mart Well-Known Member

    Hi Kev

    The difficulty I have experimentally if figuring out how to test these abstract theoretical ideas. There seem to be a paradox which is as follows;

    Most published biomechanical science seems to involve, description, breaking systems down and looking at manageable relationships between variables or correlations to try and filter out which variables are worthy of further investigation. It is limited by technology and ethical considerations for subjects.
    If we are saying there is a higher level of organisation at work which can only be understood by combining variables (reducing degrees of freedom) we are heading in the opposite direction, replacing ever increasing deconstruction with synthesis. I think this is in essence the rub for me, I cant get my head around this because it is contrary to what I have as a system within my reality of how to approach understanding things.

    I made allusion before to the issue Zen and although you may feel this is irrelevant, I actually see strong parallels. It is a philosophy which exposes paradox but is not a science. It has logical integrity, allows for me, a plausible reality which is not dependant in faith. I can and do test this plausibility from experience, within the philosophy this is encouraged but again it is not science.

    You have made reference to being open minded, I think am, particularly because I have superficial knowledge about a lot of things compared to most people I know. This makes me particularly inexpert, high sensitivity low specificity in diagnostic terms.

    I love seeing threads. There is chatter on the pod forum currently about information transmission through the intercellular matrix of MSK structures possibly augmenting a level of organisation. Recently it was discovered that elephants communicate their identity over vast distances using their feet as seismic transmitters and receivers, an interesting parallel. If evolution works as it seems there seems some value in looking out for threads. But then what to do about them?

    I have tried to post several chapters which I am using as catch up which look at fluid, joint, and biomaterial mechanics, modelling and simulation, tissue adaptation and injury. They are perfect knowledge bridge for podiatrists. The files are way too big. I am going to see if I can create an FTP link on my website so that anyone interest can get a copy. I suspect that most of you already have this knowledge bit others following the thread might find it helpful. Ill post a link if I can figure out how the FTP stuff works.

    What I am trying to figure is how to approach this subject using science, or is that impossible?


    What kind of variables have you studied, how do you test and measure them, how have you approached this issue or do you see it differently?

    cheers

    Martin



    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  26. Mart

    Mart Well-Known Member

    Hey this is the self appointed referee of this thread

    "No bareknuckle fighting you guys otherwise, tenesgrity or not, this thread will get so plastically deformed that it will start to resemble what I recently heard a food critic describe when served a plate of “Foie gras sushi” as looking like “a veterinarians biopsy tray”.

    With intense respect

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  27. Stanley

    Stanley Well-Known Member

    Re: The Turvey Paper on Synergy.

    Martin,

    If we talk about sway, there are two types related to the pelvis, but I find this is more related to a problem with the eyes. Usually when the eyes get treated the pelvis changes also.
    I have only been doing this for a few months, but it seems to work.
    The two eye dysfunctions (and these are motor dysfunctions, not vision dysfunctions) are ocular lock and visual righting reflex.
    Ocular lock is when there is an inability to track. Have the patient watch your finger as you make a large circle in front of him. Look for a glitch in movement. If you see it, note the place where this occurs. I was correcting the sutures of the front of the skull for this (except when the glitch is at 6 O'clock, then it is a posterior skull dysfunction), then I was freeing the fascia over the sutures, and now I am doing some muscle work on the obicularis oculi for it.
    I don't know how you would find visual righting reflex dysfunction. I find it when there is a weak muscle and having the patient turns the eyes either left or right (but not both)strengthens the weak muscle (additionally the neck turning both ways has to strengthen the weak muscle also). The problem is usually caused by a respiratory cranial sacral dysfunction. I have found that just freeing the fascia over the posterior of the skull helps this.
    This also helps equinus. Remember that when there is a mortise subluxation, the equinus develops. That is why manipulation of the ankle helps. There are muscle fibers in fascia that helps to maintain this joint's integrity. By changing the neurologic control (which is what we are talking about) the tonus of the fascia changes, and the mortise joint becomes stable. This corrects the equinus. Furthermore, when you do the muscle test, you are looking for the response of the nervous system (again this is what we are talking about) to respond to this perturbation. So the one correction would help all the aspects of the instability.
    This is not the only thing that can cause an equinus, but when you talk about instability, and find the glitch in the eye, a weak peroneal muscle and an equinus, you can be pretty sure there is an eye dysfunction.

    Regards,

    Stanley
     
  28. kevin miller

    kevin miller Active Member

    Kevin K.

    I am not back up on anything. In fact, the Turvey paper is making me more certain that I am right. Insults aside, I really don't understand your attitude about biotensgrity. No one is selling snake oil and there is no process at work that can't be explained with known concepts of biomechanics and physiology....which is the point David is making. I thought that the problem was vocabulary, no I wonder if it is not that Biotensegrity essentially says that every structure has multiple functions and that they enteract. This is what I don't understand that baffles you. Can you explain? Lastly, you said you wanted to stop the bickering. I am all for it. I have found some folks here who want to work through this. You are welcome to participate....even if you don't agree.....but please offer a rational explaination so that we will have something to work off of.

    Thanks,
    kev
     
  29. kevin miller

    kevin miller Active Member


    OK...I think I am begining to understand everyones concern. It is the instantaneous transmission of information...correct? There is no voodo involved. It is simple physics, only the tensile units are so tight that they function like compression units...or rather, like a guitar string. I can pluck the string on one end and the information shows up at the other end. More correctly, it it like the game where you put your elbow on a friend's arm and hit your fist. The force is instantaneously ttansmitted to his arm even though you never touched it with your hand. In other words, ther is no "spooky action at a distance."
    Kevin K, is this what you were talking about when you said something about improving energy flow? All we would be talking about is that if the joints are congruent and in proper alignment, the tensile structures would have proper tension and they would transfer the force better. Using tha elbow on the arm analogy again, you get better force transfer and more pain if the elbow is perpendicular to the arm than if it contacts at an angle.

    As for what I am looking at.... Obviously I have spent a lot of time dissecting and setting up movement experiments with cadavers, but you can only watch bones move thorugh the sequence of soft tissue structures for so long until you need something else to kill the boredom. What I am looking at now is gait efficiency and synergy of muscle firing. I.e., I have a group of muscles, each contributing "X"% of output of tourque around a joint. If i measure gait efficiency with joints in position "A", then manipulate them to get position "B" and the efficiency changes, I am seeing tensegrity or something like it in action. If I have mlpositioned joints for "A" and efficiency improves when I manipulate them.....well, you get the picture. Again, simple physics, no voodoo.

    Kev
     
  30. Mart

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.


    Hi Stanley

    Thanks for your comments.

    The eye stuff is also on my do list.

    Problem I find with this and any attempts at gait exam behond the basic tenants which are applicable to severe neurological or structural deficit is trying to seperate out the causal from the incidental.

    That applies of course to much of what we attempt diagnsotically, I gues this is why I explain to my patients often that we can go the cheap and dirty route first and if that doesnt work look a bit deeper. How do you approach this issue given the realm which you seem to occupy?

    BTW if you dont mind me asking what is your backgrouind?


    cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    phone [204] 837 FOOT (3668)
    fax [204] 774 9918
    www.winnipegfootclinic.com
     
  31. Kevin M:

    Please provide all of us with a definition of "biotensegrity". Is it defined as "every structure has multiple functions and that they interact", as you say above. If this is not the definition, then please provide the best one that you know of. It would allow all of us to better discuss these concepts. To me, "biotensegrity" can't be "tensegrity in biological structures" since the biological structures (i.e. foot and lower extremity) we are talking about have compression forces across their joints during all weightbearing activities, and therefore can't truly be "tensegrity" which Buckminster Fuller and Kenneth Snelson originally described.

    Let me give you an example. Biomechanics may be loosely defined as the mechanics of biological organisms. Biodynamics may be defined as the dynamics of biological organisms. However, biotensegrity can not be defined as tensegrity in biological organisms since it seems to be more an idea that compression and tension work together to make the body work better, without following the definitions of tensegrity as defined by Fuller and Snelson.

    The concept that compression and tension forces work together is a basic engineering concept, it doesn't need "biotensegrity", to explain these everyday interactions that occur in both non-organic and organic structures. Therefore, I don't see why we need the ethereal concept of biotensegrity to confuse the very precise and mathematically quantifiable concepts embodied in engineering science.

    Kevin Miller help us.....what is your definition of biotensegrity??
     
  32. Re: The Turvey Paper on Synergy.

    Martin:

    Which phenomena do you seek to explain that you think can't be explained using standard biomechanics and physiology concepts?
     
  33. Stanley

    Stanley Well-Known Member

    Re: The Turvey Paper on Synergy.

    Hi Martin,

    Finding the cause is what I hope to find. The problem is that when you think you have the answer, there is usually something that caused that. I have been spending years trying to find the answer. The thing that has helped me the most was learning Applied Kinesiology.

    I also started with the “cheap and dirty route” first and if the problem didn’t resolve, then I would go deeper. When I first started, I would spend many visits adjusting orthoses to get them as perfect as possible. I would see a high school cross country team weekly through their season. Now, I only see them a few times during the season to tune them up. The word has gotten out, and the patient’s expect me to start deeper. It took several years for this to occur.

    I am a podiatrist. I graduated in 1976 and was the first biomechanics fellow. In 1977, I had a surgical residency at OCPM (I am board certified in podiatric surgery). I taught at OCPM for six years in the sports medicine clinic (where the students would see 40 patients a day) and I taught the sports medicine course. I then obtained a degree and license in Massage therapy to expand my sports medicine scope of practice (we couldn’t legally treat a knee primarily back then). I then pursued a degree in Mechanotherapy. While I was a student the state eliminated licensure, but we finished our degrees expecting to get grandfathered. While we were waiting, I took courses in Applied Kinesiology ( a chiropractic discipline), so I would be ready when I obtained my license. The state decided not to grandfather us, so I just use the knowledge for treating podiatrically.

    Regards,

    Stanley
     
  34. kevin miller

    kevin miller Active Member

    This isn't exactly short and sweet, but here goes:

    Biotensegrity describes the neuromuscular-neuromechanical synergy that has evolved to allow living things to operate efficiently within the gravitational field. This includes ever-sensing and ever-adapting boney compressive structures and myofascial tensile structures separated by a cartilaginous layer at the joint lines. The purpose of the cartilaginous layer is to minimize time of contact while mediating and maximizing force/impulse transfer, through both bone and myofascial units, produced at heel strike and contact phase of gait. (This is to transfer force to the spine to drive gait.)
    Because the Biotensegrity system is composes of an inner boney skeleton surrounded by high-toned soft tissue, any perturbation of the system is instantaneously sensed and adapted for from the micro-level to the macro-level. Part of this is not a conscious sensing, rather the same corrective sensing that is noted in non-biological Tensegrity systems such as a geodesic dome, a special class of structures which sense, actuate, and give feedback; who respond to damage to any part via adaptation throughout the rest of the structure.
    While the non-biological Tensegrity system must rely on mechanics alone to adjust for perturbations, the biological Tensegrity system uses input from mechanoreceptors to adjust muscle length and tone to adapt to perturbations. (to clarify the definition of tone, it is a catch phrase for a multitude of properties including reflexes, elasticity, strength, viscosity……all properties that lend themselves to the tensile components of the system.)
    For instance, a sprained ankle creates short term swelling and long term ligamentous laxity that alters the tension-compression balance around the joint. Adaptation may occur in two ways: 1) initially tone may decrease to protect the joint from further injury. 2) long term, tone is altered to re-create the original tension-compression condition at the joint. This obviously requires that the aberrant motion be adjusted for elsewhere in the system, but the adjustment is made over the entire system, so the impact is minimal.
    We currently define theses functions in terms of proprioreceptivity – where each body segment is aware of the other, exteroreceptivity – where the body is aware of what it is in contact with, and finally, the CNS which can override reflexes triggered by the first two, but rarely needs to. The fact that this systematic assemblage has been noted from the cellular level to the macro level in all living things, not just humans only lends it credence.
    We see this in action when the gelatinous amoeba quickly moves away from negative stimulus, in the model that satisfactorily explained how dinosaurs could move and support their own weight, and how a human, running barefoot on uneven ground has little perturbation of the motion of the center of mass….. there is a zero-delay response to perturbation that can ONLY occur if all parts of the system are in mechanical and neuromechanical contact.


    Hope this helps clear up the misconception that I am selling snake oil. There is nothing here we don't already know, just put in a little different perspective.

    Kev M
     
  35. Kevin M:

    I don't think you are "selling snake oil". However, it would be nice if you could offer to all of us a concise definition of "biotensegrity", not an explanation of how you think biotensegrity works, including being the factor that allowed dinosaurs to move and support their own weight.

    Please provide a definition of "biotensegrity" in one or two sentences....such as would be given in a dictionary.
     
  36. kevin miller

    kevin miller Active Member

    Kevin K,

    In ALL seriousness, I would be honored if you would help me with this. You see, the problem is that in giving a 1-2 sentence definition, you loose the explaination that keeps it from sounding like snake oil. You have seen what I have written, how would you word it? I promise I will not immediately jump to criticize. I honestly would like to articulate this better.

    Sincerely,
    Kevin M
     

  37. Kevin M:

    Therein lies the problem with "biotensegrity". Since it can't use the conditions of the scientific (what you call engineering) definition of tensegrity, because it allows violation of those concepts of tensegrity, then I wouldn't know how to define it without sounding somewhat vague and ambiguous. From what I read of your explanation of "biotensegrity" it seems like it should be defined as "tension and compression elements within the organism working synergistically together to produce optimum mechanical function of the organism".
     
  38. Mart

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.

    Hi Kevin

    Myofascial TrPs, articular dysfunction that requires manual mobilization and fibromyalgia.

    In addition there are as yet also interesting unexplained gait modifications, an example would be: ACL tears in 75% of individuals apparently may result in substitution of quadriceps action by hip extensors as alternative knee stabilizing mechanism during mid-stance. Nothing strange about this unless it is also noticed that a similar effect was also measured contra laterally in the knee without ACL deficit. This suggests some form of gait reprogramming.

    Are we observing the influence of feedback processing in these examples? I think ideas exploring this have something to offer and because this is a difficult area to investigate it remains a frontier.

    I also perceive a commonality because these phenomena seem to have been largely sidelined within mainstream scientific /medical thought, and as a consequence either not recognized or mis-diagnosed. In addition they seem to be favored ground for “quackery” and also a suspicion of quackery even of those who attempt to recognize and treat these conditions with what I would regard as an acceptable empirical approach based on best current knowledge.

    I say this as someone who has exhibited this kind of prejudice but also recognition of my failure in a small cohort of my patients. I have recently started to explore what that might amount to with a bit more vigor, and mostly with the compass of ideas which I have gleaned on this forum, started seeing some new (to me) phenomena. I am currently treating my first patient who exhibits classic descriptions of active TrPs; (localized TrP pain and central and distal referred foot pain).

    She also exhibited failure of auto support mechanism which I attributed to causing MSK overload, treatment for this mechanically actually made things worse. It surprises me now that it has taken me so long to change my approach, 5 years ago it would have surprised me that I would be using acupuncture needles (though I do not claim to be performing acupuncture).

    I have found my as yet “early days” probing these issues fascinating if revealing an embarrassing knowledge deficit, to a certain extent though I am finding ways to do something about this. I regard the pod arena as a major catalyst.

    As I have mentioned before I regard your attention to detail, and clarity of thought hugely valuable as part of this process, and particularly look forward to your influence as what I see as a sober counterbalance to unfettered enthusiasm for as yet immature ideas.

    Cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    Phone [204] 837 FOOT (3668)
    Fax [204] 774 9918
    www.winnipegfootclinic.com
     
  39. Mart

    Mart Well-Known Member


    I agree and see this thread as an attempt to see if there is merit in pursuing and refining this idea.

    There strikes me to be an important distinction between, lets say, a geodesic dome and a living foot. An inanimate object with it’s simplicity of non living material and relative lack of motion has some measurable similarities when compared to a cadaver, both of which lack active neurologic feedback.

    Your suggested reading “A biomechanical model of the foot” does this admirably. It gives us good information to consider how the stresses within the foot change as our COM shifts over the foot during midstance.

    It cannot however tell us how live individuals will respond to this change, logically it does tell us what problems the moving body has to confront.

    Research has attempted to define what we would normally expect the body’s response to this perturbation to be and I feel we can find a fair body of published work which exams this in terms of looking at the kinetic and kinematic responses in various cohorts under certain conditions.

    Within my limited understanding there remains technical difficulty in examining the neurologic feedback processes. Surface EMG has severe technical limitations because of crosstalk and noise and I am not sure what other measurement systems currently would allow us to explore this area, at least clinically.

    Turvey points in a direction by considering ideas from mathmatics, cybernetics and biomechanics, it is largely abstract and I find it impossible to be critical because I do not really understand how he derives most of his inferences towards this "higher" level organisation.

    So I either ignore this right now, or try and find ways to understand the inferred reasoning.

    I see this as somewhat the domain of philosophy, by which I mean;

    Investigation of the nature, causes, or principles of reality, knowledge, or values, based on logical reasoning rather than empirical methods. This is an approach which I understand underpins much of mathematics and the physical sciences.

    This is how I see this exercise. I think it is a pity that the tools of this area of philosophy are not taught to us at school because they underpin much of our day to day activity and response to situations.

    How do you feel about the constraints I suggest we accept to tackle what I see as a potentialy divisive approach?

    Cheers

    Martin


    The St. James Foot Clinic
    1749 Portage Ave.
    Winnipeg
    Manitoba
    R3J 0E6
    Phone [204] 837 FOOT (3668)
    Fax [204] 774 9918
    www.winnipegfootclinic.com
     
  40. kevin miller

    kevin miller Active Member


    I understand your reluctance, but please also understand that you have this in the wrong order. The engineering definition came AFTER the biological description. I think I put a link to Ingber labs up earlier, if not, it is easy to google. He and Levin are not as stringent as the engineering definition, and from my work I think it is because we have more to work with. (e.g., articular cartilage) The argument could just as easily be that the engineers have a limited definition of tensegrity mechanics and their definition is of no use. Why are we thinking that two research MDs - one with a PhD - are any less scientists than engineers?

    Kev
     

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