Reliability of two lumbar motor control tests for people with low back pain that are feasible in clinical practice

Background: Clinically feasible and reliable methods to measure motor control in people with low back pain (LBP) are lacking. This reliability and measurement error study design (i.e. repeated measurements in stable patients) aimed to determine the intra- and interrater reliability, and measurement errors of several parameters for two clinical lumbar motor control tests. Method: Participants 18–65 years of age, with current or a history of LBP performed a spiral tracking task (n = 33; i.e., tracing a spiral on a computer monitor by making spinal movements) or a repositioning task (n = 34; i.e., returning the trunk to a predefined position). Accelerometers were used to measure trunk positions. To explore the potential of these tests, we evaluated a broad range of parameters. To assess intra- and interrater reliability, we calculated the intraclass correlation coefficient (ICC_(2,1) for absolute agreement), standard error of measurement and smallest detectable change for each parameter. Findings: Overall, the interrater reliability of the spiral tracking test was good (ICC>0.75). The reliability of the second and third trial revealed higher ICC values compared to the reliability of the first two trials. The intra- and interrater reliability of the repositioning test was overall poor (ICC <0.5, with the exception of trunk inclination: ICC: 0.5 to 0.75). Conclusion: The reliability and set-up of the spiral tracking test supports its feasibility for clinical use. Considering the poor reliability of the repositioning test, it is doubtful whether further development of this measurement protocol is indicated. Only for the direction trunk inclination further standardisation might be warranted.