The Mechanism of the Lumbar Spine
Gracovetsky S, Farfan H, Lamy C.
Spine
6(3) : 249-262, 1981.
Abstract
The moments generated in the lumbar spine by a weight lifter are
balanced by moments generated internally by muscles and by the intervertebral ligamentous
structures including the disc. Unique real number solutions have been obtained by a
optimization technique minimizing shear and penalizing excessive muscle power. The model
faithfully reproduces the electromyographic responses and all known
experimentally-determined values for muscle power and compression. The outputs can be used
to calculate a realistic motion of the spine under various loads. The model suggests that
in handling heavy loads, the stress at each intervertebral joint is identical and with
maximal voluntary effort, the weight lifter does not exceed 67% of the ultimate strength
of his tissues.
