earticle

영어

The purpose of study was to explore the influence of flexion and extension bias on the electromyographic (EMG) activities and cross-sectional area of lumbar muscles in chronic low back pain. twenty-two patients with chronic low back pain were divided into either flexion bias or extension bias groups by symptom provoking posture. The multifidus, iliopsoas, and erector spinae muscles were measured by magnetic reasoning imaging (MRI) and calculated with ratio by body of the 4th lumbar vertebra. EMG activities of multifidus and erector spinae was measured, and all the EMG amplitude were normalized into %maximum voluntary isometric contraction (%MVIC). Flexion bias group has significantly lower ratio of iliopsoas cross-sectional area than that of extension bias group (p<.05). As a result, flexion bias group has higher ratio of cross-sectional area of multifidus at the more involved side (p<.05). Flexion bias group has significantly higher %MVIC in erector spinae than extension bias group during trunk flexion and extension (p<.05). Consequently, the results of this study suggest that necessity of exercise for preventing multifidus muscle atrophy for flexion bias group.