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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

    Kev

    Tensegrity and mechanoregulation: from skeleton to cytoskeleton

    Christopher S. Chenf1 and Donald E. Ingber

    Departments of Surgery and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA, 02115




    Abstract
    Objective: To elucidate how mechanical stresses that are applied to the whole organism are transmitted to individual cells and transduced into a biochemical response.

    Design: In this article, we describe fundamental design principles that are used to stabilize the musculoskeletal system at many different size scales and show that these design features are embodied in one particular form of architecture that is known as tensegrity.

    Results: Tensegrity structures are characterized by use of continuous tension and local compression; architecture, prestress (internal stress prior to application of external force), and triangulation play the most critical roles in terms of determining their mechanical stability. In living organisms, use of a hierarchy of tensegrity networks both optimizes structural efficiency and provides a mechanism to mechanically couple the parts with the whole: mechanical stresses applied at the macroscale result in structural rearrangements at the cell and molecular level.

    Conclusion: Due to use of tensegrity architecture, mechanical stress is concentrated and focused on signal transducing molecules that physically associate with cell surface molecules that anchor cells to extracellular matrix, such as integrins, and with load-bearing elements within the internal cytoskeleton and nucleus. Mechanochemical transduction may then proceed through local stress-dependent changes in molecular mechanics, thermodynamics, and kinetics within the cell. In this manner, the entire cellular response to stress may be orchestrated and tuned by altering the prestress in the cell, just as changing muscular tone can alter mechanical stability and structural coordination throughout the whole musculoskeletal system.



    do you have a pdf of "Tensegrity and mechanoregulation: from skeleton to cytoskeleton" which you could make available, I am unable to get a copy from ny library?

    thanks

    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
     
  2. Mart

    Mart Well-Known Member

    Heres a few other papers which may be useful which I cannot get locally, anyone else able to get access to these?


    Tissue adaptation to mechanical forces in healthy, injured and aging tissues. Scand J Med Sci Sports. 2005 Aug;15(4):199-201.

    Tensegrity I. Cell structure and hierarchical systems biology. J Cell Sci 116 : 1157-73

    Opposing views on tensegrity as a structural framework for understanding cell mechanics. J Appl Physiol 89 : 1663-70


    1: Med Hypotheses. 2006;66(6):1074-7. Epub 2006 Feb 17.
    Connective tissue: a body-wide signaling network?
    Langevin HM.

    Department of Neurology, University of Vermont, College of Medicine, Burlington, 05405, USA. Helene.Langevin@uvm.edu

    Unspecialized "loose" connective tissue forms an anatomical network throughout the body. This paper presents the hypothesis that, in addition, connective tissue functions as a body-wide mechanosensitive signaling network. Three categories of signals are discussed: electrical, cellular and tissue remodeling, each potentially responsive to mechanical forces over different time scales. It is proposed that these types of signals generate dynamic, evolving patterns that interact with one another. Such connective tissue signaling would be affected by changes in movement and posture, and may be altered in pathological conditions (e.g. local decreased mobility due to injury or pain). Connective tissue thus may function as a previously unrecognized whole body communication system. Since connective tissue is intimately associated with all other tissues (e.g. lung, intestine), connective tissue signaling may coherently influence (and be influenced by) the normal or pathological function of a wide variety of organ systems. Demonstrating the existence of a connective signaling network therefore may profoundly influence our understanding of health and disease.
    PMID: 16483726 [PubMed - indexed for MEDLINE]





    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
     
  3. Mart

    Mart Well-Known Member

    Experimental tests of the cellular tensegrity hypothesis.Stamenović D, Mijailovich SM, Tolić-Nørrelykke IM, Wang N.
    Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA. dimitrije@engc.bu.edu

    The tensegrity model depicts the cytoskeleton (CSK) as a prestressed network of interconnected filaments. The prestress is generated by the CSK contractile apparatus and is partly balanced by traction at the cell-substrate interface and partly by CSK internal compression elements such as microtubules (MTs). A key feature of tensegrity is that the shear modulus (G) must increase in proportion with the prestress. Here we have tested that prediction as well as the idea that compression of MTs balance a portion of the cell prestress. Airway smooth muscle cells were studied. Traction microscopy was used to calculate traction. Because traction must be balanced by the stress within the cell, the prestress could be computed. Cell G was measured by oscillatory magnetic cytometry. The prestress was modulated using graded concentrations of contracting (histamine) or relaxing (isoproterenol) agonists and by disrupting MTs by colchicine. It was found that G increased in proportion with the prestress and that compression of MTs balanced a significant, but a relatively small fraction of the prestress. Taken together, these results do not disprove other models of cell deformability, nor they prove tensegrity. However, they do support a priori predictions of tensegrity. As such, it may not be necessary to invoke more complex mechanisms to explain these central features of cell deformability.


    Here's anoother paper I could not get hold of if anyone else can, although it deals with measuring cellular mechanics some criteria and methodolgies might be worth understanding when thinking about "up the scale" investigations.

    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
     
  4. Stanley

    Stanley Well-Known Member

    Mart,

    I find this section particularly interesting:
    4.2. Appreciating fascia
    The architectural organization of the cell proposed and defended by Ingber and colleagues (e.g., Ingber, 2003a, 2003b) can be taken as a model for the level of muscular–articular links (Fonseca & Turvey, 2006; Turvey & Fonseca, in press). The development of a tensegrity hypothesis of the level of muscular–articular links begins with an appreciation of the involvement of fascia in muscular coordination. There is a need to consider a fascia network alongside the neural network.


    I think this means that the fascia is another communication system (in addition to its other functions).
    The acupuncture meridians closely parallel the fascial trains in the body, so we have a communication/support system. If we take this a step further, there are emotional points in the acupuncture system, so the fascia also responds to emotions (and the posture along with it).

    Fascinating paper, it puts together several parts and pieces into a coherent theory of structural/neurologic intergration.

    Regards,

    Stanley
     
  5. kevin miller

    kevin miller Active Member


    Mart, have you gone to Ingber labs web site or Steven Levin's web site? Both of those have fine papers attached. If you can't get them through an easy google search, let me know and I'll find them for you.

    Kev
     
  6. David Smith

    David Smith Well-Known Member

    Dear All

    As a definition for tensegrity in the terms of a biological system perhaps the following might suffice.

    “Tensegrity describes a structural-relationship principle in which structural shape is
    guaranteed by the finitely closed, comprehensively continuous, tensional behaviors of the system and not by the discontinuous and exclusively local compressional member behaviors” (Fuller 1975b, 700.011)
    --in addition-----
    In the biological system the joints that allow free range of motion without severe and probably pathological increased stress in the tensional components (as pointed out by Flemmons) are seperated by a system of pneumatic/hydraulic psuedo tensegrities namely the cartilage. (Me 2008)

    However, these criteria of tensegrity definition appear to make the case, for the bilogical system as a tensegrity, difficult.

    1)They have no redundant parts, although new tendons can be added to
    consolidate the structure. (Kenner, 1976).

    2)They don’t depend on gravity due to their self-stability, so they don’t need
    to be anchored or leaned on any surface. The systems are stable in any
    position. The force of gravity, basis of the conventional architecture, is
    nullified (Perlberg, 1977)

    Muscle systems do have redundancies out of necessity. To reduce weight the muscles are obliquely orientated to the joint and therefore have the potential to work synergistically with other muscles to produce the action required. This criteria is still possible when some muscles are redundant due to injury. This is not possible with orthoganally oriented muscles unless there is duplication of each muscle.

    Higher organisms most definentely do require the influence of gravity to maintain integrity. As been pointed out many times in this and the other thread (spring ligament discussion) gravity has a significant influence on anatomical structure and form.

    Cheers Dave
     
  7. kevin miller

    kevin miller Active Member



    David,

    I've got to think about this one for a while. The original tensegrity...biotensegrity...evolved over millions of years with gravity as a primary pressure. There is no way we can leave it out. Also, down to the most simple single cell exhibiting avoidance behaviors toinstantaneous adaptation to topographical change in gait, there is a neurochemical component as well. This IS the basis for the synergies that Turvey talks about and is the focus of my next little science project. How do we get these two VITAL components in there?

    Kev
     
  8. Mart

    Mart Well-Known Member

    Kev

    May be I'm missing something but if I go to the wesite the papers are cited but not available even in abstract form. Any suggestions?

    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. efuller

    efuller MVP

    Hi all,

    The article attempts to make movement more complicated than it is. Yes, the crtique of classifying muscles as agonists or atagonists is simplistic is a valid critique. However the replacement is too complicated and clouded further by the writing style. "feature of bi-labail closure" = putting your lips together. This is a writing style that makes it difficult to actually understand the intent of the author. Several people have commented on how difficult it is to read the article.

    The article is saying that a group of muscles can combine to create complex motions or actions. They list all the muscles required for speach. Yes it is incredibly complex to create speach if you were to individually stimulate the muscles by pushing a button. But, it is not so complex that it cannot be done by a brain that is connected directly to the muscles. We are able to speak.

    Now, the process by which you study how these muscles can work can go down several paths. You can try the tensegrity path and I defy anyone to reproduce the explanation of how that works. Or you can try and look at the effect of each individual muscle contraction. That is muscle contraction produces a force. This force is applied to another anatomical structure. Accelerations might occur in response to these forces. Motions can be explained in terms of these forces. Speach can be explained in terms of forces, etc. on the vocal chords. The world can be explained using mechainics. We can make measurements of forces and accelerations and make predictions of changes in observed motions from changes in the magnitudes of forces.

    Will someone explain to me how tensegrity helps explain motion. What measurements can we make that we can use tensegrity to help predict motion? How do we make those predictions.

    We can observe a phenomenon and then say that phenomenon is caused by tensegrity. We could also say that phenomenon is caused by magic. There is not differnece between magic and tensigrity. They are just words used to fool our minds into believing that we can explain why things happen. It is often very comforting to name something. Just because we give something a name does not mean that we understand it.

    Cordially,

    Eric
     
    Last edited: May 21, 2008
  10. efuller

    efuller MVP

    On the transition of tensegrity from the cellular level to the level of bones. There is a difficulty of seeing the forest for the trees. The individual cells may function as tensegrity structures, but this does not translate to larger structures. For example fascia. The structure of fascia and ligaments is such that structure of individual cells is not related to the mechanical properties of larger anatomic structure. It's the combination of the collegen fibers that allow a ligament or fascia to be able to withstand tensile forces.

    Bone gets its resistance to compression from hydroxyapitite crystals froming into the shape of a bone and not from piling osteocytes on top of each other. Cellular tensegrity does not cause whole body tensegrity. To look at whether or not whole body tensegrity exists you need to look at structures like bones and ligaments and muscles. These structures don't fit the tensegrity where there is no contact between the compression members.

    To repeat a question posed earlier. How does tensegrity help us explain anything?

    Regards,

    Eric
     
  11. Mart

    Mart Well-Known Member

    Hi Eric

    I posted this thread with intent to do 2 things:

    See if there was anything useful to learn from the paper.

    See if this is a tree worth spending any time barking up.

    Kevin Kirby asked me earlier what phenomena I thought the kind of approach you have both advocated might not be able to explain. I did reply, no one has responded to that post yet (#38).

    My “feeling” currently (and I have a bunch of reading I’m trying to get through) is that tensegrity, as a loosely defined concept, may give us insight into mechanisms which influence MSK function by modulating muscle activity from mechanosensor feedback pathways which either involve neurologic control which has so far not been understood or via another system of feedback which is being hinted at in the literature probing the phenomena I listed.

    I am unable to be critical because I do not have depth of knowledge but am catching up slowly.

    Essentialy what happens within joint and myofascial structures at a cellular level (we know there is mechanosensory input there) and how "mechanical" signals may be transmitted (as opposed to or in concert with ion flow mediated nerve conducted signals) could confound us if something poorly understodd is happening. If this possibility proves to be logically flawed lets rule it out and not waste time on it. I used an analogue of the seismic comunication of elephants as the nearest "up scale" example I could draw on which I think is a useful parallel, if someone told me this without substantiating I would have thought "nice bit of BS is it April fools day?". If you can see logical flaw in this please help me out

    Perhaps those participating in this trhead will persuade me that this is not worth the effort. So far it is motivating me to learn things which are useful in other areas too. So far nobody has given convincing argument that there is nothing waiting up the tree worth at least having a yap at :). I am curious to learn about what is being written about at the cellular level if I can get my hands on the papers, anyone able to do this?




    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 21, 2008
  12. Stanley

    Stanley Well-Known Member

    http://www.anatomytrains.com/uploads/rich_media/c04c7252238ff6f72d81f52c89a20f85.pdf

    Regards,

    Stanley
     
  13. kevin miller

    kevin miller Active Member

    I'm not sure Mart,. I have always just been able download anything from Levin and I have gotten a couple of things frim Ingber by simply double clicking the link.
    \\Kev
     
  14. David Smith

    David Smith Well-Known Member

    Eric


    Good point well put :good:

    Dave
     
  15. Mart

    Mart Well-Known Member

    Hi Eric

    Agreed, from a scientific viewoint this needs to be possible, curently within the foot and lower limb this has not been demonstrated.


    I think this is also true but is also true of phenomena which we use in biomechanics which we do not usually question. Could you not also say the same of the term gravity? The difference is that it's effects can be measured predicably within the scale of human anatomy, however if you change the scale of distance that becomes difficult for many of our physical measurements.

    Tensegrity, if it does exert an effect on our bodies and if it is measurable as an entity must be a combination of effects, this compounds the issue. That is why I am curious to read the papers which I understand have attemped this at a cellular level.

    More questions than answers right now.


    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



    Martin
     
  16. Eric, I couldn't have said it better myself. Excellent.

    Martin:

    Gravity is not only measurable, but gravity is also predictable using mathematics. Both Robert Hooke and Sir Isaac Newton described this a few centuries ago as the inverse square law of gravity . Science is based on mathematics. Physics is based on mathematics. Biomechanics is based on mathematics. Can we say that biotensegrity is based on mathematics, or is it more a theory that tries to explain phenomena, like magic, without paying particular attention to any mathematical proof?
     
  17. efuller

    efuller MVP

    Re: The Turvey Paper on Synergy.


    Hi Mart,

    The reason that I did not try to explain phenomenon with engineering is that I did not understand what you are referring to. What is a TrP? If you use abbreviations you should spell it out first once and then follow with abbreviation in parentheses. Could you explain further what you mean by articular dysfunction?

    I will admit that I have no explanation for fibromyalgia.

    I've seen papers trying to explain gait changes with ACL injury. The ACL prevents rearward translation of the femur relative to the tibia. The hamstrings can also prevent the same motion. So, to prevent knee instability the individual uses more hamstring and this causes a simultaneous hip flexion moment that has to be counterd (to stay erect) by hip extension. If you look at this in terms of Winter's concept of support moment it makes sense. Yes there is some gait reprogramming. The subject is choosing different muscles to achieve the same motion. It would also appear that they are choosing symmetry.


    Regards,

    Eric
     
  18. Mart

    Mart Well-Known Member

    Hi Kevin and Eric

    I don’t know . . . .. . . but don’t worry I am not planning an apprenticeship to become a wizard. :eek:

    In terms of the "human" sphere of activity I agree that we understand enough about gravity that we will never have much practical need for better theories than the ones we now have.

    I think I was beginning to stray off into the world of metaphysical questions about our knowledge, where we don't really understand ANYTHING about our physical world at the deepest level . . . . and you are right this is not the place to be getting into this.

    You have rejected the possibility of a unifying notion of tensegrity explaining some as yet mysteries of MSK function. I need to learn a lot yet to get to my own decision making point, at which time if I find something convincing I’ll be sure to ask you to examine this further.

    cheers

    Martin :drinks

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

    Mart Well-Known Member

    Re: The Turvey Paper on Synergy.

    TrP = myofascial trigger point.

    Articular dysfunction which responds to "mobilisation". The apparent short or long term effects of applying manipulative therapy to change the range of motion of joints or associated musculoskeletal (MSK) structures.

    sorry Eric I assumed these abbrevs were already in general use.

    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
     
  20. kevin miller

    kevin miller Active Member

    Eric, kevin,

    I beg to differ with you about using majic in exchange for tensegrity. As far as I know, I can't measure magic, nor can I see it work. I can do both of these with tensegerity. If I alter the tensegrity mechanism, I can change gait efficiency. I can set up a demonstration and watch the secondary function of tensile structure do their thing. Maybe we should drop the word tensegrity. I don't care, but there IS a synergiystic action that goes on which involves both the mechanincs and neuromechanics which is not explain well with current theory. The key being the neuromechanics. Do you thi9nk the Turvey paper is about majic?

    Regards,
    kevin M
     
  21. I actually think tensegrity that B. Fuller and Snelson have described has enough mathematical rigour and precision to be a useful term that we can still use. However, I can't say the same for the term "biotensegrity" since I still really don't know what its definition is.

    Kevin M., please explain how you could set up a demonstration of tensegrity mechanisms of the body that would support the theory that tensegrity mechanisms are present. Please also list the expected results so that all of us can understand what you are seeing in your research. The big question would be if there are alternate theories, other than tensegrity, that could describe the observed experimental more scientifically and more logically.
     
  22. kevin miller

    kevin miller Active Member

    Kevin K,

    This is reasonable and makes sense. In fact, I asked myseldf the same question. I'll tell you what I am doing now and i would appreciate any feedback that might help ti to be a better study.

    Premise 1) Tensegrity structures are synergies
    Premise 2) Theses synergies transfer information instantaneously
    Premise 3) There is a neuro logical as well as mechanical component
    Therefore, if I could test for variation in efficieny of the synergy correlated with variation in neurological funtion pre and post joint manipulation (i.e., firing of mechanoreceptors) Then I could state that there is a link between instantaneous correction and the synergy. Is my logic faulty?

    Here is what I am going to do: I have a 15 lead research grade EMG that will be placed on the motor points of specific muscles. This will test my neuro. I will us the com'nalysis program on the F-scan to measure gait efficiency. I will pretest, then treat and post test. Simple, to the point, easy to blind..... what do you think?

    Kev
     
  23. Stanley

    Stanley Well-Known Member

    Eric, you are the last one that I would expect to make this argument. Too complicated???? After digesting the engineering articles with all the calculus, I find this Turvey article to be slow reading, but at least it is possible.



    And does the brain do this in a complex neurologic manner, or is this the magic that you have alluded to? Remember that speech uses a special part of the brain involved with fine movements (the Betz cells, and the pyramidal tracts)

    Eric, I agree with you to a point. For the engineering concepts to work, the model has to be correct. The problem is that the models are too simple. I know you do some weightlifting, so show me how your engineering model explains how someone can squat 1000 lbs, and not rupture a disc, and then someone can rupture a cervical disc with only the weight of the head to deal with. A failure of the tensegrity system to unload the discs explains this perfectly well. Simplistic engineering that does not take into account the bones suspended in the fascia does not.

    Eric, you talked about how complicated things are, and to make the correct measurements, would require an accurate model. I agree, it is too complicated. So instead of making simplistic models that do not explain things very well, currently concepts that explain it are where things appear to be at now. In the future, as more is understood, then the completed model can be made that will allow for measurements.

    So if you do not understand something, and someone uses a name to describe this, then it is either magic or it does not exist? This is similar to your usage of the brain to describe speech. Are you suggesting the brain makes speech by magic?

    Regards.

    Stanley
     
  24. Stanley

    Stanley Well-Known Member

    Kevin,

    The theory of gravity is not set in stone.:eek:
    http://www.msnbc.msn.com/id/7047871/
    Gravity sure sounds like magic to me-dark energy and hidden dimensions.
    Next time I read a physics book, I will have to have a talisman with me. :wacko:

    Stanley
     

  25. Stanley:

    Did I say that the theory of gravity was set in stone? You must be reading between the lines......again.:bang:

    Since you are on the tensegrity bandwagon, Stanley, by claiming that engineering models cannot explain disk failure but tensegrity can explain the failure:
    maybe you can give all of us your definition of "biotensegrity"? Wouldn't you think that a proper definition of something you are claiming causes disk failure would be a good start to helping the rest of us understand what you are talking about?
     
  26. kevin miller

    kevin miller Active Member

    Kevin K.,

    I am aking this again because I may not ahve been clear on what I WAS asking.. Given the parameters weh ahve set out, how would YOu word a definition. To whit....

    We are dealing with a synergistic system

    Each part of the system is conected to each other part and communicated force and other impulses via mechanical and neuromechaical means. (This is how the "majic" instantaneous adaptation occurs - no magic)

    The compressive uints - bone- give the body its base structure and mainatain limb integrity, also surving as attachements for the tensile structures

    The tensile structures ever change their "tone" to maintain the proper ossoeus alignement and make sure there is varied and short term compression on the articular cartilage......what have I left out? I left out something, but you get the picture. OH...does there need to be a statement concerning the coevoluton of these different parts that produce the synergy?

    Kevin M
     
  27. Kevin M:

    I am not trying to be difficult, even though at times I find myself very frustrated with this whole discussion. The reason I have asked both you and Stanley for a good short definition of "biotensegrity" is because I honestly don't have a clue how one could concisely define "biotensegrity" since it seems to mean different things to different people. It certainly isn't "biological tensegrity" since animals, such as humans, use compression forces between its bone/structures, which we call "joints", in order to stabilize and transfer forces and moments through the articular mechanisms that result. Therefore, if "biotensegrity" is not tensegrity, and it is something different, then what exactly is it?:bang:

    I don't like wasting my time on unscientific theories, since there are so many good scientific theories that I feel the need to spend my time on becoming better acquainted with. There are only so many hours in a day, as you know. As you can see from my thought experiments here on Podiatry Arena, I have used mathematics to try to establish a firm foundation for the physical phenomena that I have observed and measured.

    Can you give me any research that has objectively measured "biotensegrity", in other words, has quantitatively measured "biotensegrity", so I can feel more sure that "biotensegrity" isn't just a concept that is a pure theory, with absolutely no objective evidence to support it. Maybe you can design one of your own thought experiments to better show us all what you are talking about?
     
  28. efuller

    efuller MVP

    I thought the Turvey paper was about making something more complex than it really is. What do you think the paper is about?

    What measurments do you on tensegrity? As I recall the definition, that you provided earlier, of biotensegrity was vague and when the definiton is vague it is difficult to do measurements.

    You can do something to a body and witness a change in how it moves. That does not mean that you altered the tensegrity system. It does not mean that there is a tensegrity system. Measuring a limb length discrpency is not measuring tensegrity it is measuring the length of a limb.

    Regards,

    Eric Fuller
     
  29. efuller

    efuller MVP


    I don't understand premise 1. What do you mean by synergy. How can a structure be a synergy?

    What is your research question? Just because an EMG chagnes after you do something does not mean there was a synergy altered.
     
  30. Mart

    Mart Well-Known Member

    I managed to get hold of all the papers which I requested and some, thanks again for those who help me with that.

    I have been trying to run before I can walk with this from the outset. I have been reading as much as I have had time to and can see the light at the end of the tunnel (I think).

    David has already pointed to the root of the problem in this circular headbanging and I think can already start to explain this in a way in which the “skeptics” and “true believers” may find useful.

    A couple of important issues;

    Turvey’s paper is not about tensegrity he talking about hierarchy of organization of which he sees tensegrity as a component.

    Ingber’s paper Tensegrity and mechanoregulation: from skeleton to cytoskeleton is very easy to read and lays out quite clearly how he sees the interplay between compressive and tensile forces exerting influence on morphology of MSK structures at organ, tissue and cellular level which in itself I found very compelling.

    I understood Wolfes law but had no sense of how this might work other than a vague notion that form follows function and that living tissues respond actively to stress and change structurally to accommodate this within certain limits. Ingber’s research suggest that cells walls have receptor sites which bind to extracellular matrix structures which define the possible 3D configurations. He also has research which looks at intracellular mechanical structures. Within the world of physiology this is contentious, for a podiatrist looking into what this amounts to is tough but I'll try and address this later if I can.

    Overwhelmingly Inber sees Turveys notion of hierarchies and tries to explain part of this in real life terms rather than noticing phenomena or speculating on abstract ideas which is what Turvey has done (he made no claims to have done otherwise).

    If you can be patient for a couple of days I will try and post a comprehensive interpretation of the other papers I received and see how that fits into this debate.

    In finding a useful angle here’s a couple of questions which will help me write something useful.

    Kevin and Eric; do you have an explanation for the nuts and bolts of Wolfs Law? If so please could you outline how this works.

    Kev and Stanley: do you agree, as Ingber categorically states, that compressive forces do act within joints and that this notion of tensegrity must include strut structure transmitting force through joints? I think you have already said this but not directly.

    I think we still have a way to go with this lets avoid :bash: or :deadhorse: though

    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. efuller

    efuller MVP

    Maybe more complicated is not the right term. What it does is make some observations and then says that the whole is greater than the sum of the parts and starts talking about tensegrity. There is a lack of connection between the observations and naming tensegrity.

    Watching a child learn to walk and learn to speak is an amazing thing. It takes years for the brain to LEARN how to do these things. Yes it is a complex neurolgical task to activate all the right muscles in sequence to create speach. It's learning and not biotensegrity.

    Stanley, As a weight lifter, you know it is all about technique. If try to squat 1000 lbs with poor technique you get injured. The brain has learned to allign the muscles and bones in the proper position so that the task can be performed. If you don't pay attention at some level, you can hurt your back picking up a pencil. The injury occurs because an anatomical structure was stressed beyong its breaking point. Lifting your own weight, with poor form, can create stresses that break anatomical structures.

    See finite element analysis. You can refine the mechanical model quite far. However, you only need to refine the model to the point where you can make useful predictions.

    I never said someting did not exist. What I said was that naming something does not create understanding or explanation. I agree that we can't explain gravity, but we can sure predict what it will do. What predictions do you make with your knowledge of tensegrity? What predictoins so you make with your knowledge of magic? What predictions do you make with your knowledge of gravity? Are your predictions made with tensegrity the same as those you could have done with engineering principles?

    Regards,

    Eric Fuller
     
  32. efuller

    efuller MVP

    Wolf's law in relation to bone. I recall a maxim that was explained physiologically where bone formes udner tension and is resorbed under compression. A classic example of this occures post a head osteotomy bunionectomy. Over the years you can see the curved bone "straighten." The metatrasl undergoes end to end compression via the windlass mechanism. When a curved column is loaded there will be compression on the inside of the curve and tension on the outside of the curve. Bone formes on the inside of the curve and you get a straighter metatarsal.

    Wolf's law is a generality. You have to look at the physiology of the individual tissues to figure out how they are actually work.

    Regards,

    Eric
     
  33. Mart

    Mart Well-Known Member

    Eric

    This is exactly what Ingber attempts, very specifically not just for bone but ligament, tendon and myofascial junction. He does this using "the heirarchical" model (to conform to the jargon).

    Now what I am unsure about is, how much depth you have on this subject and if you have read this paper. I think it possible that he may have something novel to add to your understanding or perhaps simply explains something you already understand from another route.

    That is part of the problem as I see it in trying to get us on the same playing field.

    If you have the inclination please let me know, at the very least I can sumarise his idea but dont want to waste either of our times if you have already studied this paper.

    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
     
  34. kevin miller

    kevin miller Active Member

    Martin,

    I went to those links and were able to pull them up. On the ingber site, it is a simple click on the paper. On the Levin site, got to papers. them read more after the preface. They are all there.


    Eric and Kevin K. I don't know what to say. To me, biotensegrity ti easier to understand than engeneering tensegrity. Maybe you could read the Turvey paper a little closer? He certainly isn't making something more complex, he is explaining that everything works in synergy, not in linear fashion.
    Kev
     
  35. Stanley

    Stanley Well-Known Member

    What you said was ”Gravity is not only measurable, but gravity is also predictable using mathematics.” I took the term predictable to mean that the results will occur time and time again, otherwise why would the predictions change? Obviously my vocabulary skills are not as refined as yours, so I looked up the meaning of prediction.

    Prediction is: http://dictionary.reference.com/browse/prediction

    1. an act of predicting.
    2. an instance of this; prophecy.
    forecast, augury, prognostication, divination, projection

    So I stand corrected. Gravity is not set in stone, it is magic, or more accurately akin to reading tea leaves. I am still dusting off the talisman. :rolleyes:

    Since you have been on the engineering bandwagon a lot longer than I started to understand the tensegrity concepts, first show me how engineering explains how the discs do not rupture in a person doing a 1000lb squat, while another person can rupture a cervical disc with no additional weight on his head. My point is that the body can be explained in engineering terms when the model is accurate enough, but currently, the engineers that model the body do not include all the tensile elements.

    Stanley
     
  36. Stanley

    Stanley Well-Known Member

    Eric,

    If you see a high ASIS on the side of an equinus, you would measure this, and your treatment would be dependent somehow on your measurements.
    Part of the tensegrity theory is that if one tensile element is not working properly, the results can be seen somewhere else.
    This pattern is one that I would approach by finding the reason for the equinus and/or the weak anterior scalene and then correcting it.
    How would you approach it with your measurements?

    Regards,

    Stanley
     
  37. And I am very proud to say that I am a podiatrist that is on the "engineering bandwagon". I believe that over the past two decades of my career, I may have already converted many podiatrists to thinking more scientifically about foot and lower extremity function, in other words, thinking like an engineer. Sorry, Dave Smith, you are an engineer already!

    There are many acceptable engineering explanations for why a disk may rupture in one person but not in another. First of all, congenital or acquired weakness of the disk which would mean that possibly the elastic modulus or stiffness of the disk is decreased congenitally, by an acquired condition, by changes in hydration or by the effects of aging on the collagen fibers that make up the disk that would make it more susceptible to herniated nucleus pulposis (HNP) than another disk, given the same pressures acting on the disk. Secondly, changes in muscle strength or abnormal postural positions or certain physical activities may alter the disk pressures at each level so that a HNP may result.

    If you think that tensegrity is the only explanation for your observations, Stanley, then that is all that you will find or you won't look for other answers that are much more scientific. Please do a simple google search on "herniated nucleus pulposis". I think that you will find many more descriptions of why disks fail using standardly accepted terminology used by the international biomechanics and international engineering communities than you will find using "tensegrity".
     
    Last edited: May 23, 2008
  38. Stanley

    Stanley Well-Known Member

    Eric, I was replying to your statement:
    You are discussing setion 1.1. There is no mention of tensegrity at this time. He is talking about concinnity. Even though I never heard this word before, I looked it up:
    http://en.wikipedia.org/wiki/Concinnity
    It is a perfect word to describe this harmonious reinforcement of the parts.

    Eric, I was asking if the usage of brain is any different than the usage of tensegrity. They are just words used to fool our minds into believing that we can explain why things happen.


    With your engineering background can you mathematically show me how the stress on the lumbar spine of squatting 1000 pounds with good technique is less than that of the head on the neck? How does the body reduce the load on the disc with proper technique, when all the muscles will cause increased compression (in the standard engineering model)? By the way, I have watched lots of tapes of world class weight lifters with friends at get togethers, and we all remarked what butchers these guys are. :butcher:They are just incredibly strong and fast.


    Prediction is: http://dictionary.reference.com/browse/prediction

    1. an act of predicting.
    2. an instance of this; prophecy.
    forecast, augury, prognostication, divination, projection
    Without all the elements, you are predicting. With all the elements you would know.



    For one, I can predict that I can level the hips without heel lifts of orthoses.
    I will leave the magic predictions to you.
    Tensegrity is a part of engineering, and when the engineering model is correct, then it would be easy for anyone to make the predictions with engineering principles.

    Regards,

    Stanley
     
  39. efuller

    efuller MVP

    Stanley,

    I would go about it pretty much the same way you did, but I could do the same thing without using the word Tensegrity. This is my point. Using the word tensegrity adds an unecessary level of confusion and complexity.

    Regards,

    Eric
     
  40. efuller

    efuller MVP

    The point we have been making is that tensegrity is the wrong engineering model. The bones of the body are not continuous compression elements held appart by tension elements.

    Now if you alter the definition of tensegrity to mean whatever you want it to then you can change the definition to the correct engineering model. But, that would be confusing.

    Regards,

    Eric
     

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