title: [Study on reliablility of flexion-extension ratio in surface EMG for the diagnosis of nonspecific chronic low back pain].
abstract: OBJECTIVE
  To evaluate the reliability of flexion-extension ratio (FER) of lumbar erector muscle in surface EMG for the diagnosis of nonspecific chronic low back pain.
  
  
  METHODS
  According 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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  FER of lumbar erector muscle might be practically applied as an objective indicator on the diagnosis of nonspecific chronic low back pain in surface EMG.
authors.affiliation: General Air Force Hospital, Beijing 100036, China. kzzp@sina.com
authors.forename: Jie
authors.initials: J
authors.lastname: Wei
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Hua-Xiong
authors.initials: HX
authors.lastname: Xing
mesh_terms: D002908:Chronic Disease; D004576:Electromyography; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology