Study of the validity and reproducibility of the Biering-Sorensen test in chronic low back pain

Issue Dynamometric trunk muscle strength and endurance test are performed widely within the rehabilitation management of chronic low back pain. Objective To examine the validity and the reliability of the Sorensen test in patients with chronic low back pain. Patients and methods Fifty-nine subjects were included divided into 2 groups: the first group included 30 chronic low back pain patients and the second group included 29 healthy controls. Anthropometric data of all subjects in both groups were collected for comparability study. Construct validity was investigated with the use of the Spearman rank correlation coefficient (convergent and divergent validity). As for convergent validity, it was investigated via correlation between the Sorensen test with isokinetic dynamometer parameters at 60 and 120°/s, and isometric at 60° trunk flexure, the Borg scale, the 6-minute test, and the Beck Scale. Divergent validity was studied via correlation between the Sorensen test and visual analogue scale (VAS) pain, VAS functional impairment and the Oswestry score. Intra-rater reliability was assessed by use the intra-class correlation coefficient (ICC) and the Bland and Altman method. Results Both groups were comparable at basic characteristics. Convergent validity of the Sorensen was judged good. We found significant correlations between the Sorensen test and the others parameters: the isokinetic and isometric parameters (respectively [ r  = 0,5, p r  = 0,58, p r  = 0,4, p  = 0,02), and the Shirado test ( r  = 0,59, p p  u003e 0.05). An intra-raterreliabilityof the Biering-Sorensen test was (ICC = 93.2%) in chronic low back pain patientsand (ICC = 96.6%) in the control group. Discussion The Biering-Sorensen test demonstrated his good validity and his reliability in the evaluation of trunk musclesendurance. Consequently, this test could be recommended for the muscular assessment in the management of all patients with chronic low back pain.