Abstract
The purpose of this study was to investigate the reliability and validity of the ClinometerTM smartphone application. Intrarater and interrater reliability were calculated for devices (i.e., goniometer, ClinometerTM, bubble inclinometer) using intraclass correlation coefficient, standard error of measurement, and minimal detectable change. Interinstrument reliability and ClinometerTM 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 ClinometerTM validity were supported across analyses. The ClinometerTM is comparable to a goniometer or bubble inclinometer for measuring prone knee flexion.