The reliability and validity of joint range of motion measurement using zoom and a smartphone application

[Purpose] This study aimed to evaluate the reliability and validity of measuring the range of motion of joints using a remote videoconferencing system (Zoom) and a smartphone application. [Participants and Methods] This study included 16 young and healthy adults. The participants were instructed to perform shoulder joint flexion exercises in a seated position, with automatic motions, and maintain that posture throughout the measurement. Two measurements were performed: 1) angle measurement using a three-dimensional (3D) motion analyzer, and 2) angle measurement using the videoconference software, Zoom, and a smartphone application. Intra- and inter-rater reliabilities were calculated using the intraclass correlation coefficients (ICC). The degree of agreement between the representative values of each measurer and the 3D motion analyzer was examined. [Results] ICC (1, 1) for intra-examiner reliability were 0.912 and 0.996. For the inter-rater reliability, the ICC (2, 1) was 0.945. The correlation coefficient between each examiner’s value and the value of the 3D motion analyzer was 0.955 and 0.980, respectively. The Bland–Altman analysis results indicated no systematic error. [Conclusion] The method of remotely measuring joint range of motion using Zoom and a smartphone application demonstrated high reliability and validity.