Clinical biomechanics
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Clinical biomechanics · Apr 1996
Quantitative intramuscular myoelectric activity of quadratus lumborum during a wide variety of tasks.
Intramuscular fine-wire electrodes monitored the electromyographic activity of quadratus lumborum in four young adults. A wide variety of tasks were performed including flexion tasks, lateral bending, twisting, extension, and lifting tasks. Heavy lifts of barbell weights up to 70 kg activated the quadratus lumborum 74% of their maximum on average while surface recording of erector spinae (L(3)) were only 62% of their maximum activation. ⋯ Furthermore, it increased activation in response to increasing compression in static upright standing postures. RELEVANCE:--Electromyographic evidence, together with architectural features make the quadratus lumborum a better stabilizer of the spine than psoas. Use of horizontal 'side support' exercise to train this muscle would appear to be a wise choice.
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Clinical biomechanics · May 1988
E.m.g./moment relationships in neck muscles during isometric cervical spine extension.
The aim of the study was to describe the e.m.gJmuscular moment (torque) relationships for neck and shoulder muscles during cervical spine extension. Ten healthy women participated. Their average age was 25·6 years. ⋯ Simultaneously with the force recording, the e.m.g. activity was recorded through surface electrodes applied unilaterally at six locations in the neck and shoulder region. The rectified low-pass filtered e.m.g. signals were normalized against the highest activity level obtained during a series of standardized isometric test contractions. The results show that a non-linear e.m.g./moment relationship exists in axial musculature of the cervical spine, with a slightly higher increase in e.m.g. levels at high muscular moment values.