View Full Version : Muscle stress by fiber type

07-08-2003, 06:50 AM
I'm a PhD candidate looking at spine modeling for congenital scoliosis
(where one of the vertebrae is deformed). I am modifying an existing model
of a normal spine and have a question about muscle stress for erector

The model currently uses a value of 35 N/cm^2 for muscle stress, but
studies of fiber type & scoliosis have shown a greater than normal
percentage of Type 1 fibers on the convex side in congenital scoliosis and
a normal percentage on the concave side(refr 1-5) (N.B. this is different
than idiopathic scoliosis). I would therefore like to change the convex
muscle stress value to reflect this.

But in reviewing the muscle stress literature & biomchL archives i have
been unable to discover a concensus on what the muscle stress by fiber type
should be, although there seems to be agreement that it changes with fiber
type, and also changes with different muscles (refr 6-10).

I would appreciate any thoughts, suggestions or references on what a
reasonable value for erector spinae with predominantly Type 1 fibers should

I will gladly post a summary of responses.
Many thanks,
Sheila Purkiss
PhD. Candidate
University of Toronto/Hospital for Sick Children
Toronto, Canada
1. Bylund, P., et al., Clin Ortho & Rel Res, 1987. 214: 222-8.
2. Gonyea, W.J., et al., J Ped Orthop, 1985. 5(3): 323-9.
3. Meier, M.P., et al., Spine, 1997. 22(20): 2357-64.
4. Willner, S., The Pediatric Spine: Principles and Practice, S.L.
Weinstein, Editor. 1994, Raven Press, Ltd: New York. 445-462.
5. Yarom, R. and G.C. Robin, Spine, 1979. 4(1): 12-21.
6. Buchanan, T.S., Med Eng Phys 1995. 17(7): 529-36
7. Chang Y-W., et al., Clin Biomech 1999. 14: 537-42
8. Koo T.K., et al., Clin Biomech 2002. 17: 390-99
9. McMahon T.A. Muscles, Reflexes and Locomotion. 1984, Princeton
University Press: New Jersey
10. Schneck D.J. Mechanics of Muscle: Second Edition. 1992, New York
University Press: New York.

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