title: Force and time recording for validating the sacroiliac distraction test.
abstract: OBJECTIVE
  The present aim was to investigate whether applied force and time interval of force exposure during the sacroiliac distraction test could discriminate subjects with sacroiliitis pain from healthy subjects.
  
  
  METHODS
  The study was a methodological one using force plates sensing three orthogonal forces.
  
  
  BACKGROUND
  Studies evaluating the validity of sacroiliac joint tests show conflicting results. To our knowledge, no previous studies have evaluated force recording combined with pain reports.
  
  
  METHODS
  Eleven subjects with sacroiliitis and 11 healthy subjects were examined with distraction test once by each of three physiotherapists. The subjects indicated any pain by pressing a button giving a mark in the data collection.
  
  
  RESULTS
  The magnitude of the total force vector was significantly smaller (P<0.05) and the time interval was significantly shorter (P<0.05) in the sacroiliitis group, although almost 20 s could elapse before pain was provoked. The sensitivity of the test was 0.55 calculated for all physiotherapists involved, and varied between them, range 0.55-0.82. The specificity was 1.0.
  
  
  CONCLUSIONS
  The results support the advantage of force and time recording during the distraction test as a technique for evaluating pain. Further investigation is needed on whether the velocity of force application, the ability to maintain the same pressure and the bilateral distribution of force on the sacroiliac joints influence the sensitivity.
  
  
  CONCLUSIONS
  There is a need for objective evaluation methods in manual tests that are easy to perform. Recording force and its time interval may be a step towards standardising pain-provocation sacroiliac joint tests.
authors.affiliation: Division of Physiotherapy, Neurotec Department, Karolinska Institutet, 141 83 Huddinge, Stockholm 23100, Sweden. ulla.levin@neurotec.ki.se
authors.forename: Ulla
authors.initials: U
authors.lastname: Levin
authors.forename: Christina H
authors.initials: CH
authors.lastname: Stenström
mesh_terms: D000328:Adult; D000368:Aged; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010147:Pain Measurement / Q000295:instrumentation / Q000379:methods*; D010808:Physical Examination / Q000295:instrumentation / Q000379:methods*; D010812:Physical Stimulation / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012446:Sacroiliac Joint / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013166:Spondylitis / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D013314:Stress, Mechanical