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THE AXIAL TORQUE OF THE LUMBAR BACK MUSCLES: TORSION STRENGTH OF THE BACK MUSCLES
Author(s) -
Macintosh Janet E.,
Pearcy Mark J.,
Bogduk Nikolai
Publication year - 1993
Publication title -
australian and new zealand journal of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.111
H-Index - 51
eISSN - 1445-2197
pISSN - 0004-8682
DOI - 10.1111/j.1445-2197.1993.tb00520.x
Subject(s) - medicine , lumbar , longissimus thoracis , trunk , anatomy , low back pain , longissimus , torque , back pain , abdominal muscles , core stability , physical medicine and rehabilitation , electromyography , surgery , tenderness , physics , ecology , alternative medicine , pathology , biology , thermodynamics
The maximal, axial torque generated by the lumbar back muscles was determined by modelling the action of the 49 fascicles of longissimus thoracis, iliocostalis lumborum and the lumbar multifidus on radiographs of the lumbar spine of nine young male subjects in upright standing and in full lumbar flexion. No single fascicle exerted more than 2 Nm of axial toque in the upright posture, and the collective torque of all muscles acting a segment did not exceed 5 Nm. All torques were considerably less in full flexion. The lumbar back muscles exert very little torque on the lumbar spine, and contribute only about 5% of the total torque involved in trunk rotation. None of the lumbar back muscles can be considered a rotator. The oblique abdominal muscles are the principal rotators of the trunk. Preventative and rehabilitation programmes concerned with torsion injuries should focus on the abdominal muscles rather than the back muscles for stability in axial rotation.