Concurrent Validity and Reliability of a New Smartphone Application for Measuring Cervical Range of Motion in Healthy Individuals

Abstract

BACKGROUND: Range of motion (ROM) measurement is an important part of physical therapy assessment and patient progress. Smartphones are user-friendly instruments and if proven to be reliable and valid, clinicians can use them for a variety of tasks including ROM measurement. OBJECTIVES: To determine concurrent validity and intra- and inter-rater reliability of the PhysioMaster application in measuring cervical ROM in both Android and iOS operating systems. METHODS: Forty-five healthy individuals (age 31.75 ±11.94 yrs; 18 men, 27 women) completed this study. Two raters measured cervical ROM, three times each, using an Android phone for intra-rater and inter-rater reliability. With an interval time of 1–7 days after the first session, measurements were repeated by one of the raters once to measure inters- ession reliability. Validity was estimated by one of the raters using iPhone and Android phones one at a time while 3D motion analysis (3DMA) recorded cervical movements simultaneously. For reliability, intraclass correlation coefficient (ICC), and for validity, Pearson correlation coefficient and Bland-Altman plots were used. RESULTS: ICC values of ≥0.76 and ≥0.84 demonstrated excellent intra-rater and inter-rater reliability, respectively. For concurrent validity, correlation between each phone and 3DMA was nearly per- fect for all movements (0.93 ≤r ≤0.97). CONCLUSION: PhysioMaster appears to be a valid and reliable application for measuring cervical ROM in healthy individuals.