Reliability and Validity of the Clinometer Smartphone Application™ for Measuring Knee Flexion

Abstract

The purpose of this study was to investigate the reliability and validity of the Clinometer™ smartphone application. Intrarater and interrater reliability were calculated for devices (i.e., goniometer, Clinometer™, bubble inclinometer) using intraclass correlation coefficient, standard error of measurement, and minimal detectable change. Interinstrument reliability and Clinometer™ validity were also assessed. Intrarater reliability was good (intraclass correlation coefficients = .70 − .83) and interrater reliability was moderate (intraclass correlation coefficient = .63 − .72) across devices. Interinstrument reliability and Clinometer™ validity were supported across analyses. The Clinometer™ is comparable to a goniometer or bubble inclinometer for measuring prone knee flexion.