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Updated: Jun 25, 2026

Biomechanical Changes Related to Low Back Pain: An Innovative Tool for Movement Pattern Assessment and Treatment Evaluation in Rehabilitation
Published on: December 13, 2024
Lumbar flexion and dynamic EMG among persons with single level disk herniation pre- and postsurgery with radicular
Agnes S Wallbom1, Michael E Geisser, John Koch
1Spine Program, Department of Physical Medicine and Rehabilitation, University of Michigan Health System, Ann Arbor, Michigan, USA.
Objective:
The paraspinal muscles often fail to relax on forward flexion in many persons with low-back pain. The goal of this prospective study was to determine whether this abnormal lack of a flexion-relaxation phenomenon corrects after lumbar diskectomy for symptoms of radiculopathy with low-back pain.
Design:
Electromyographic testing was performed on 17 patients before and 30 days after lumbar diskectomy.
Results:
Although pain improved significantly (P < 0.05), the flexion-relaxation phenomenon did not improve.
Conclusions:
Failure to recover muscle relaxation while pain is relieved suggests another mechanism for paraspinal activity.
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