Abstract
BACKGROUND: Smartphones and tablets can be used by clinicians to measure 2D joint and segment kinematics, which helps inform important treatment decisions. However, whether 2D kinematic measures obtained with these devices are reliable is unknown. OBJECTIVE: This study examined the inter- and intrarater reliability of 2D kinematic measures obtained using handheld devices. METHODS: CINAHL, Embase, PubMed, and SPORTDiscus database searches were performed using Medical Subject Heading terms, keywords, and text words related to reliability, handheld device, 2-dimensions, video analysis, application, kinematics, and functional movement. The initial search resulted in 407 potentially relevant titles. Following title, abstract, and full-text screening, 8 studies were included in this review. To be included, studies must have examined the inter- or intrarater reliability of 2D joint or segment kinematics measured using digital video on either a smartphone or tablet. Study quality was evaluated using the Quality Appraisal of Reliability Studies (QAREL) tool. RESULTS: Inter- and intrarater reliability intraclass correlation values varied considerably between and within studies. These varied reliability findings can be attributed to differences in testing protocol and equipment, activity examined, the discrete point of interest during an activity (e.g., time of initial contact or peak knee flexion), and joint(s) or segment(s) of interest. CONCLUSION: Using smartphones and tablets to measure 2D joint and segment kinematics clinically is promising as it can be performed reliably. However, clinicians should be aware of the potential impact of their methodological decisions on the reliability of joint or segment kinematics obtained using these handheld devices. TRIAL REGISTRATION: This study was registered with PROSPERO on May 12, 2022 (CRD42022330137).