Reliability of Measurements of Pelvic Lateral Tilt in the Supine and Standing Positions: Rater's Measurement error and Reproducibility of Subject's Posture

[Purpose] The purpose of this study was to verify the reliability of measurements of pelvic lateral tilt and clinical utility, including rater's measurement error and reproducibility of subject's posture. [Subjects] In this study, 10 healthy subjects (10 male; aged 19 to 23) participated from whom informed consent was received. [Methods] We measured pelvic lateral tilt in 4 static postures (supine, standing with feet together, apart feet and feet wide apart) using a goniometer and a inclinometer. Two investigators measured pelvic lateral tilt in all positions. To estimate intra-rater and inter-rater reliability, the intra-class correlation coefficient (ICC) was calculated for the experimental data. [Results] Intra-rater reliabilities ranged from 0.652(ICC1,1)/0.790(ICC1,2) for standing with feet together to 0.886/0.940 for standing with the feet wide apart. Inter-rater reliabilities ranged from 0.784(ICC2,1)/0.879(ICC2,2) for standing with feet apart to 0.884/0.938 for the supine position. [Conclusion] We conclude that this measurement method has reasonable reliability and clinical utility.