Reliability and Validity of Smartphone Measurement of Spinal Angular Amplitude and Velocity

Background Spinal movement alterations have been identified as a potential contributor to low back pain (LBP) disability. However, current evidence is predominantly based on cross-sectional laboratory studies, limiting the understanding of how these alterations relate to the development or persistence of LBP. The availability of smartphones equipped with inertial measurement units offers a unique opportunity to assess spinal movement outside laboratory settings, enabling large-scale and repeated measurements in real-world environments. This study aimed to evaluate the withinand between-session reliability, as we…