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View Full Version : Searching explanation of ligament contraction (strain hardening)



Robert Schleip
05-31-2004, 03:26 AM
Dear Colleagues
I am a new member of this list and would like to find out if anybody else is
exploring strain hardening behavior of ligaments and fascia, or knows of
some recent studies who address this.

Background: The study of Yahia LH et al 1993 on “Viscoelastic properties of
the human lumbodorsal fascia” describes their discovery of an unexpected and
remarkable tissue behavior which they named “ligament contraction”: e.g. the
resistance force (stiffness) for the same amount of strain tends to be
stronger at the second stretch if the tissue is isometrically stretched in
vitro for 15 minutes, then kept at rest for 30 minutes, and then stretched
again for 15 minutes. Our group recently confirmed this reversible behavior
with lumbar fascia of both mice and pigs.

As such temporary tissue contraction seems to offer some exciting
perspectives (e.g. for sports injury prevention, or myofascial release
practitioners) our group so far followed the suggestion in Yahia’s study in
doing a histological search for contractile cells in the human lumbar
fascia. Yet our preliminary results seem to indicate that the density of
such cells is probably not sufficient enough to explain the full amount of
strength increase. Therefore we are now looking also for explanations on a
non-cellular basis, i.e. in relation to viscoelastic behavior changes in
collagenous tissues. Our literature search incl. Medline found it mentioned
a few times in the early biomechanics literature of the Sixties to early
Eighties as „strain hardening“ tissue behavior in response to repeated
stretch, yet without any detailed experimental exploration or molecular
explanation.

My question therefore is: Is anybody aware of other studies or specific
explanations? All suggestions will be appreciated ! (and a summary of
responses will be shared later).

Robert Schleip, M.A.
Ph.D candidate, Dept. of Applied Physiology, University of Ulm, Germany
Email: robert.schleip@medizin.uni-ulm.de

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