The Biomechanics of the Thoracolumbar Fascia
Macintosh JE, Bogduk N, Gracovetsky S.
Clinical Biomechanics
2 : 78-83, 1987.
Abstract
The back muscles alone are unable to provide the extensor moment required to lift large
weights, and must be aided by another source of anti-flexion moments. It has been
postulated that contraction of the abdominal muscles can provide an extension moment by
developing tension in the thoracolumbar fascia (TLF). Anatomical studies and a
biomechanical analysis, however, reveal that the anti-flexion moment generated in this way
is only very small. Too little of the abdominal musculature attaches to the TLF to
generate a significant tension in it. Previous calculations of the forces in the TLF have
overestimated the tension developed in it because of erroneous assumptions and
interpretations of the relevant anatomy. Whatever the role played by the TEF in lifting it
must be essentially independent of abdominal mechanisms.
Relevance
This study illustrates the importance of consulting or determining the anatomy integral to
a biomechanical theory before undertaking calculations and ascribing the functional
significance of postulated mechanisms. Controversies concerning the possible mechanisms
that assist the back muscles during the act of lifting are addressed.
