Abstract: Objective To investigate the features of surface electromyography of lumbar muscles in non-specific low back pain (NLBP) patients when they were practicing different types of bridging exercise. Methods 18 healthy subjects (control group) and 18 NLBP patients (NLBP group) were included and asked to practice bridging exercise with single and double feet. The root mean square (RMS) of surface electromyography of both sides of lumbar muscles were recorded. Results No significant difference was found in the control group. The RMS of erector spinae was more in the supported side than in the contra side for NLBP patients in bridging exercise with single foot. There was no significant difference among different time points in the same muscle. Conclusion The contractions of erector spinae in both sides are not equal in asymmetric bridging exercise in NLBP patients.

Key words: non-specific low back pain, lumbar muscles, bridging exercise, surface electromyography