Introduction With the widespread use of mobile devices and the rapid development of mobile networks, connecting mobile personal health record (mPHR) apps to wearable devices to collect personal health data for analysis and community activities has become a trend for health promotion. Therefore, the present study aims to explore the vital factors that impact the sustained usage of mPHR apps. Objective In this study, we identified social lock-in as a major research gap in the current era of social media and the Internet. Therefore, to explore the effects of mPHR apps on continued app usage intention, we combined technology fit (individual-technology, synchronicity-technology, and task-technology fit) and social capital (structural, relational, and cognitive capital) to develop a novel study model. Methods The purpose of this research is to investigate the willingness to participate in the mPHR apps. It collected 565 valid users’ responses through the online questionnaire with a structural equation modeling approach. Results That technology and social lock-in significantly affected the willingness of users to continue using mPHR apps ( β = 0.38, P < 0.001) and that the effects of social lock-in ( β = 0.38, P < 0.001) were more pronounced than those of technology lock-in ( β = 0.22, P < 0.001). Conclusions The technology and social lock-in generated by technology fit and social capital had positive effects on continued app usage and the effects of both types of lock-in on continued app usage varied among different participant groups.