The reliability and validity of the Biering-Sorensen test in asymptomatic subjects and subjects reporting current or previous nonspecific low back pain

Study Design. A reliability study and case-control study were conducted. Objectives. To determine the reliability and discriminative validity of the Biering-Sorensen test. Summary of Background Data. A low Biering-Sorensen score has been found to predict who will have nonspecific low back pain. However, the reliability of the test remains controversial, implying that some studies may have produced results that underestimated the magnitude of the predictive validity of this test. Methods. Two raters measured the time holding a specific position (holding time) of 63 subjects (23 currently experiencing nonspecific low back pain, 20 who had had an episode, and 20 who were asymptomatic) while they performed the Biering-Sorensen test twice, 15 minutes apart. A standardized protocol was followed. Test-retest reliability was evaluated by calculating intraclass correlation coefficients (ICC 1,1), 95% confidence intervals (CI), and standard errors of the measurement (SEM) for the total group and for the subgroups. A three-way analysis of variance was used to determine whether test order, subject gender, or symptom status affected holding time. Results. High reliability indices were obtained for the Biering-Sorensen test in subjects with current nonspecific low back pain (ICC [1,1], 0.88; 95% CI, 0.73-0.95; SEM, 11.6 seconds), in subjects who had had nonspecific low back pain (ICC [1,1], 0.77; 95% CI, 0.52-0.90; SEM, 17.5 seconds), and in asymptomatic subjects (ICC [1,1], 0.83; 95% CI, 0.62-0.93; SEM, 17.4 seconds). Results of an analysis of variance showed that subjects asymptomatic for low back pain had a significantly longer holding time than the other two groups (P < 0.05). Conclusions. The Biering-Sorensen test provides reliable measures of position-holding time and can discriminate between subjects with and without nonspecific low back pain.