“…Given the ubiquity, easy accessibility and high acceptability of smartphones, applications (apps) that use these built-in IMUs for gait monitoring combined with easy-to-use interfaces, automatic data processing and analysis, and real-time reporting on gait performance may overcome the limitations of stand-alone IMUs. There is emerging evidence for the validity and/or reliability of smartphone apps to quantify spatio-temporal gait parameters in children and adolescents 30 , young and/or older adults 31 – 38 , and patients with (neuro-)muscular pathologies 39 – 42 . Apart from a few exceptions (e.g., Apple Health, OneStep, Gait Analyzer), most of these apps still focus on standardized measurements of gait capacity by providing multimedia instructions for self-administered test protocols 34 – 36 , 39 , 40 and depend a standardized smartphone placement (e.g., sacroiliac belt) 35 , 36 , 39 , 42 .…”