Objective: Accurate assessment of lumbar range of motion is of great value for both evaluating lumbar functions and monitoring treatment progress. Recent research indicates that there is no general consensus on the most valid and reliable method of measuring spinal range of motion. The purpose of this study was to determine the intra-rater reliability of lumbar flexion and extension measurements (within-day and between-days) using the dual inclinometer technique.  

Materials & Methods: Lumbar flexion and extension of 22 women (14 healthy and 8 with low back pain), were measured by the same examiner on three occasions. The first two measurements were taken with half an hour apart on the first occasion to assess the within-day reliability and the third measurement was taken one week later to assess the between-days reliability. 

Results: Within-day lumbar lordosis, flexion and extension measurements using dual inclinometer technique were shown to be very reliable with high Intraclass Correlation Coefficients (ICC) values (ICC were 98%, 77% and 69% for lordosis, flexion and extension measurements, respectively in healthy subjects and 94%, 95% and 69% for lordosis, flexion and extension measurements, respectively in patients group). Between-Days measurements also demonstrated high reliability with the high values of ICC (ICC were 96%, 70% and 67% for lordosis, flexion and extension measurements, in healthy subjects and 91%, 71% and 66% for lordosis, flexion and extension measurements, respectively in patients group).

Conclusion: The results indicated that, the dual inclinometer technique appears to be a highly reliable method for measuring lumbar lordosis, flexion and extension and can be used as a reliable tool in the assessment of lumbar range of motion and monitoring therapeutic interventions.