Objective. This review synthesized the currently available literature on the effects of family-based interventions using smartphone apps on youth physical activity. Design. Systematic review. Data Sources. 1037 studies from eight databases were retrieved. Eligibility Criteria for Selecting Studies. The seven articles included in this review met the following inclusion criteria: (1) experimental studies, (2) using smartphone apps, and (3) involving families with healthy children/adolescents. Results. Studies were stratified according to whether they used smartphone apps only or the combination of sports wearables and their associated companion app. The smartphone app interventions showed significant improvements in youth's PA levels. All but one of the studies reported no significant improvement in PA levels after the intervention. However, positive PA-related outcomes were found, and the combination of sports wearables and their associated companion app showed inconclusive results due to the small number of studies. A trend of the relevance of families in improving the PA levels of youths was found. Conclusions. The findings of this review indicate that more research is needed on the effects of family-based interventions using mobile apps on youth's physical activity. Mixed results were found for variables related to the PA of the youth involved in these programs. Although strong evidence was found that youth's physical activity levels do not always improve with the implementation of these programs, promising results were found for a positive impact on different variables related to physical activity. Therefore, more experimental studies using only a mobile app to promote PA as the main outcome are needed to understand the real effect of mobile apps on youth's PA levels. Future studies need to further explore this topic by developing programs based on designs of high methodological quality.
Keywords: adolescents; children; eHealth; mHealth; smartphone.