Reliability and validity of the Microgate Gyko for measuring range of motion of the low back

Background: The aim of this study was to test the inter- and intrarater reliability and the concurrent validity of the Gyko Microgate for the assessment of lumbar range of motion. Methods: A cross-sectional study was carried out with two groups of healthy participants. The first group, consisting of 91 subjects, was tested to determine the inter- and intrarater reliability. Concurrent validity was assessed with comparisons with an optical motion system (Vicon) in a second group of 20 subjects. Lumbar range of motion in flexion, extension, left and right lateral flexion were performed. Intraclass correlation coefficient (ICC) was calculated for both analyses. Measurement error was calculated with standard error of the measurement (SEM), smallest detectable change (SDC) and Limits of Agreement (LoA). ICCs were considered good when ICC ≥0.80 and excellent with ICC ≥0.90. Results: Interrater reliability was good to excellent with ICCs ranging from 0.82 to 0.94. Intrarater reliability was good to excellent with ICCs ranging from 0.84 to 0.95. Concurrent validity was excellent with ICCs varying from 0.90 to 0.95. LoA were highest in interrater reliability and smallest in concurrent validity. SEM ranged from 2.2 to 4.0° in lateral flexion left and flexion respectively. SDC varied from 6.1 to 11.1°. Conclusion: Gyko has good inter- and intrarater reliability and excellent concurrent validity compared to the optical motion system for lumbar range of motion. Gyko may be considered as objective measure to measure range of motion for clinical purposes, however trials with patients are currently lacking.