Biomch-l users:

Thanks to all of those who responded to the request concerning
surrogate muscle. I would also like to ask if anyone has a Matrox 1024 B
framegrabber board (used in the Peak5 Motion Analysis System) that they would
be willing to sell for $250 or so.

Posted Oct 20th:

We are attempting to develop ways of mimicking active muscle forces in
cadaveric specimens. The most simplistic way of doing this is to put a
spring in series with an attachment to the muscle belly or to the
tendon. We would appreciate information concerning the use of
"surrogate" muscles, particularly with regard to the following areas:

1) appropriate spring stiffnesses, especially for the triceps
surae/Achilles tendon complex
2) appropriate initial forces/tensions to apply
3) reliable attachment techniques to the tendon or muscle during dynamic
impacts (i.e., suturing, freeze clamping, special adhesives, etc)
4) the use of a pulley system to apply static muscle forces

Thank you in advance for you time and input.

Brian P. Self

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Summary of Responses

1) The condition of the cadaver specimens and the duration of the tests
must be considered when determining the method of fixation. Don't rely
on dead tissue to support loads during dynamic situation- attach directly
to bone.

2) Some references which might be helpful are Wickiewicz 1983 (discusses
architecture) and Hoy, Zajac, and Gordon, 1990 J. Biomech 23:157-69.

3) A system at UCSD wraps the tendon stump around a pin, then clamps down
on the bight and pin to avoid stress concentrations in the tissue.

4) Neil Sharkey at the Sacramento Medical Center uses freeze clamps
attached to computer controlled actuators to apply forces at the shoulder

5) Forces in the Achilles tendon can be as high as 10 x body weight for
dynamic movement and 3-4 x BW during static toe raises according to one

6) A commercial product called "Muscle Wires" applies a force under the
control of an electric current. For more information, contact
Mondo.tronics, Inc at

7) Many researchers have sutured lines to the tendon and applied dead
weights to the tissue by means of pulleys.

8) One investigator mentioned the lambda theory of Feldman, which
proposes that muscle acts as a variable stiffness spring. If a motion
occurred during a time when the stiffness was relatively constant, then a
spring of appropriate stiffness could be used as a surrogate muscle.

Thanks again to everyone who responded to my inquiry.