OBJECTIVETo evaluate the reliability of flexion-extension ratio (FER) of lumbar erector muscle in surface EMG for the diagnosis of nonspecific chronic low back pain.

METHODSAccording to diagnostic study strategies, 73 patients with chronic low back pain and 86 controls were recruited in this study, FER of lumbar erector muscle were recorded in surface EMG for all the subjects. The critical value of FER for the diagnosis of nonspecific chronic low back pain was selected according to the receiver operator characteristic curve by SPSS. Sensitivity, specificity and accuracy were calculated and analyzed as well.

RESULTSThe FER in patients group was significantly higher than that in the control group. The critical value of FER was 0.68 with sensitivity, specificity and accuracy was 78.1%, 95.3% and 87.4% respectively.

CONCLUSIONFER of lumbar erector muscle might be practically applied as an objective indicator on the diagnosis of nonspecific chronic low back pain in surface EMG.