Reliability of three lumbar sagittal motion measurement methods: surface inclinometers

Three surface methods for measuring lumbar sagittal motion (LSM) were tested for reliability. The three methods used were the Pleurimeter V double inclinometer, the carpenter double inclinometer, and the computerized single sensor inclinometer. In this study, 30 volunteers were examined independently by three occupational health professionals. Each volunteer rotated twice through three stations at which LSM was measured by each of the three methods. The intra- and interexaminer reliabilities in identifying the skin levels of T12 and S1 were acceptable, having intraclass correlation coefficients (ICC) greater than or equal to 0.75. With a single exception, all ICC values for the intraexaminer reliability of LSM measurements fell below 0.90 (a clinically desirable level). The interexaminer reliability was poor, with all ICC values below 0.75. The largest source of measurement error was attributable to the examiner and its associated factors. We concluded that the intra- and interexaminer reliabilities varied greatly, limiting the clinical usefulness of the three surface methods.