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David Smith
06-01-2007, 07:59 AM
Hi all

Here is a summary of replies to RE: [BIOMCH-L] Tensegrity in biological systems and musculo-skeletal in particuar

Q) "I am interested in what research, within the biomechanics /engineering community, is being done in terms of Tensegrity in biological systems. I am particularly interested in musculo-skeletal systems. Can a Mamalian, and the Human's in particular, musculo-skeletal system be regarded as entirely a tensegrity structure?"


A) Sumitra rajagopalan sugested http://www.biotensegrity.com/

Kevin Miller wrote

High David,
I doubt this will be to your satifaction, but www.biotensegrity.com, run by Stephen Levin, a retired orthopedic surgeon who has been promoting tensegrity theory for over 20 years, has a section with links to quite a few papers. His work is not like Gracovetsky's, with enough math to make your head spin, but he has arguments that are sound in that they take into acount what we already know in physiology. For instance, he has a vidie where he is showing an arthroscope going on. No matter how wuch weight he and the surgeon put on the joint, it will not close down. There is at least a milimeter clearance. We should have known this anyway. Articular cartilage under constant pressure, losses intrasellular fluid. The meniscus can handle and deflect momentary compression as can many visoelstic materials, but even if it is constantly compressed, as we see in
a knee with genu valgum, the cartilage wears thin and arthritis takes hold. Much of his logic is like this, though some is in more depth, especially when he explains how movement does not occur like a pulley-lever system and how if it did we would has serious functional problems.

Andrew Philips wrote
have been doing some research on the use of muscular and ligamentous
boundary conditions as used when modelling hard (bone) tissue. I must
admit that I only came across the term 'tensegrity' when reading your
post. However assuming it to suggest that muscles and ligaments act in
tension while bone acts in compression I would say the verdict is still
out. There are parts of bones, taking the femur as an example that are
without doubt primarily under compression. However I think there are
strong arguments to say that other parts are primarily under tension
during a range of activities. I think what is interesting, taking the
femur as an example again is that the 'design' of the femur, in terms of
parts of it being under compression relies on the shape of the bone as a
whole. Were tensile parts of the bone to suffer lysis the overall
behaviour would be changed significantly. I think there is likely to be
some mileage in terms of taking volumetric and engineering octahedral
strains as guides to bone formation. As a structural engineer by
training I find the idea intriguing, and look forward to reading other
responses.

Adrian Smith wrote

May be of interest:
http://www.heall.com/body/altmed/definitions/treatments12.html

"Series of twelve movements advanced by author Carlos Castaneda, Ph.D.,
reportedly born Carlos Cesar Arana Castaneda in 1925, in Peru. Castaneda
supposedly learned these movements from his teacher, Juan Matus (Don
Juan), a reputed Yaqui sorcerer (brujo). ("Don" is a courtesy title that
means "nobleman" or "gentleman.") The purported design of Tensegrity is
to "gather energy" and promote well-being. Its theory posits an "energy
body." (According to Castaneda, his teacher was born in 1891. But the
alleged reality of Castaneda's Don Juan is doubtful.) "

Otherwise, "(tensile integrity) structure: a structure where
interconnected tensile and compressive load distribution is used to
create great strength. ..."
www.chenzhonghua.com/Articles/chen_taiji_glossary.htm

or Wikipedia?

Robert Schliep wrote and attached the papers - thanx.

great question!
To my knowledge the 1999 paper by Chen & Ingber is the only one addressing the suitability on the macroskopic scale (Osteoarthritis Cartilage 7: 81-94). Plus several by Stephen Levin not listed on Medline (www.biotensegrity.com). Your question will be also a major subject at the www.fascia2007.com congress in Boston (Oct 3-4 2007), at which Ingber will be one of our keynotes.

Fascianatedly yours

Stephen Levin wrote

If I didn't know better, I would think you are a shill for my website, http://www.biotensegrity.com . Forgive me for asking but do I know you? (I am hopeless with names). I can't find you in my emails or having registered on my website.


To answer your question; I know of no one (aside from yours truly) in the 'conventional' biomechanics community who is involved with tensegrity at the organism level. There is a group at UCONN, CESPA (http://ione.psy.uconn.edu/), that approach organism function on a holistic concept and they have presented papers and written some on the subject, but they are not nuts-and-bolts biomechanists. There are many (Ingber, Wendling and others) who have studied tensegrity mechanics at the cellular, sub-cellular and tissue level. There are reports on protein molecules, cells, lung, eye, bone, liver, etc. You can do a PUBMED search and find lots.



Please, if you do get any replies to your posting, I would love to read them, (the good, the bad, and the ugly).


I did talk to the Podiatry Institute's meeting in San Diego in 2004 and I have been in contact with several podiatrists over the years, so maybe podiatrists are ahead of the curve. (I suspect you already know of them. If not, I can put you in touch). Conventional biomechanics is steeped in the Borelli, 'lever man' paradigm, and that is a hard nut to crack. They can give approximations of local, reductionist mechanical function, but can't give you a clue as to how the foot mechanically impacts on the back, etc.. As far as I know, no conventional biomechanist has recognized that what is shown to be true at the cellular level may also be true at the organism level, and then had the hutzpah to follow up and test it.

Micheal Riley wrote

Sergio Fonseca at Universidade Federal de Minas Gerais (Brazil) is doing some work on this.

Doug Richard suggseted

Have you checked out the work of Stephen Levin MD and others
whose theories he promulgates?

It is summarized on his website, www.biotensegrity.com

Frans van der Helm wrote

My answer is no, the musculoskeletal system is not a tensegrity system.
I refer you to Letters to the Editor in the J. Biomechanics:

Levin SM
The scapula is a sesamoid bone
JOURNAL OF BIOMECHANICS 38 (8): 1733-1734 AUG 2005

van der Helm FCT, Gupta S
Reply to: "The scapula is a sesarnoid bone", letter to the editor by Dr.
Stephen M. Levin
JOURNAL OF BIOMECHANICS 38 (8): 1734-1736 AUG 2005

Key element in a tensegrity structure is that there are no bending
moments in a strut, which can only be true if pure forces (and no
moments) are exerted at the endpoint of a strut. From an esthetic point
of view, the struts should not touch as well. Bones do touch each other.
Ligament structures exert moments from one bone to the other. Muscles
attach everywhere on the bones, and not only at the endpoint.
Considerable bending moments are present in the bones.

My conclusion: A musculoskeletal system is not a tensegrity structure.

With kind regards,

I replied to Frans:-

Hello Frans

Thanks for your reply. Nice to see someone has an opinion.
Would you have a copy of those letters as I do not have a subscription
to
the Journal of Biomechanics (its pretty expensive as subscriptions go.)

Again Frans plus letters attached - Thanx.

Dear David,

Progress in science is a matter of strong opinions and a good debate! I
hereby send you the papers. I did not check if my message came through
in BIOMCH-L. I send it to the list but it happened that my sender
address was unknown, so it bounced. I updated but I did not resend
again. You are welcome to send my opinion to the list.

With kind regards,
ME - Love that first line