Abstract: ObjectiveTo investigate the application of surface electromyography (sEMG) in patients with lumbar disc herniation. Methods44 patients with chronic lumbar disc herniation were divided into mild pain group (group A) and moderate to severe pain group (group B) according to their scores of Visual Analogue Scale (VAS). Their sEMG at erector spinae and gastrocnemius were collected, and the average EMG (AEMG), slope of median frequency (MFs) were analyzed. ResultsCompared with those in the healthy side, AEMG of erector spinae and gastrocnemius reduced significantly (P<0.05) in affected side in both groups, while the MFs (absolute value) increased (P<0.05). Compared with those in group A, the MFs (absolute value) in affected side significantly increased in group B (P<0.05). The ratio of healthy/affected side of AEMG increased in group B (P<0.05), but the ratio of MFs was no significantly difference between 2 groups (P>0.05). ConclusionSurface EMG, of both the erector spinae and gastrocnemius, can be used as a non-invasive tool in detecting neuromuscular function of lumbar and lower limb in patients with lumbar disc herniation. The sEMG imbalance may respond with the severity of pain.

Key words: lumbar disc herniation, surface electromyography (sEMG), Visual Analogue Scale (VAS), functional assessment, average EMG (AEMG), slope of median frequency (MFs)