Clinical biomechanics
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Clinical biomechanics · Jan 2001
Comparative StudyIntervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force.
To determine whether repeated motion with low magnitude joint forces, and flexion/extension moments consistently produce herniation in a non-degenerated, controlled porcine spine motion segment. ⋯ The results support the notion that intervertebral disc herniation may be more linked to repeated flexion extension motions than applied joint compression, at least with younger, non-degenerated specimens. Relevance. While intervertebral disc herniations are observed clinically, consistent reproduction of this injury in the laboratory has been elusive. This study was designed to examine the biomechanical response and failure mechanics of spine motion segments to highly repetitive low magnitude complex loading.
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Clinical biomechanics · Jan 2001
Comparative StudyAn EMG technique for measuring spinal loading during asymmetric lifting.
To compare two methods of calibrating the erector spinae electromyographic signal against moment generation in order to predict extensor moments during asymmetric lifting tasks, and to compare the predicted moments with those obtained using a linked-segment model. ⋯ The calibration method does not influence extensor moments predicted by the electromyographic technique in asymmetric lifting, suggesting that simple, sagittal-plane calibrations are adequate for this purpose. Differences in predicted moments between the electromyographic technique and linked-segment model may be partly due to different anthropometric assumptions and different amounts of smoothing and filtering in the two models, and partly due to antagonistic muscle forces, the effects of which cannot be measured by linked-segment models. RelevanceAsymmetric lifting is a significant risk factor for occupationally-related low back pain. Improved techniques for measuring spinal loading during such complex lifting tasks may help to identify work practices which place the spine at risk of injury.