Abstract Background: Rapid developments in technology have encouraged the use of smartphones in pediatric evaluation research and practice. Although many applications (apps) relating to physical activity are available from major smart-phone platforms, relatively few have been tested in research studies to determine their effectiveness in evaluation of children strength and muscle power. Aim of Study: The aim of the study to evaluate intra-rater reliability of smart phone application in measuring range of motion among normal children. Material and Methods: In this article, we summarize data on use of smartphone apps for estimating range of motion based upon bibliographic searches with relevant search terms in PubMed and Google scholar. Results: After screening the abstracts or full texts of articles, 20 eligible studies of the acceptability or efficacy of smartphone apps for increasing physical activity were identi-fied. Of the 20 included studies, 9 were comparative research studies, 8 were reliability studies and 2was across sectional studies. The results indicate that smartphone appscan be efficacious in pediatric evaluation although the magnitude of the intervention effectis modest. Participants of various ages and genders respond favorably to apps that automaticallytrack range of motion, track progress toward evaluation goals, and areuser-friendly and flexible enough for use with several types of range of motion. Conclusions: In conclusion, Dr Goniometer smart phone application can be used in clinical practice and research as an easy and convenient alternative to a digital and universal goniometer.