Following the Quantified Self (QS) movement, sports apps increasingly adopt self-tracking technologies that offer data-driven insights into personal competencies to enhance self-efficacy. However, sustained engagement with QS technology remains challenging, as interpreting data is complex. One potential solution is to make QS data more meaningful to users. To address this, we present a player card feature within a QS sports app, incorporating a personalized avatar to enhance users’ enjoyment, data meaningfulness, and self-efficacy to promote continued use. We evaluate the app through a field experiment in a soccer context to examine the impact of the avatar feature. Results indicate that avatar identification positively affects self-efficacy, data meaningfulness, continued use intention, and enjoyment, though enjoyment did not impact continued use. Our findings suggest that (1) avatar identification can be enhanced through personalization, (2) personalized avatars effectively boost self-efficacy, and (3) sustained engagement may rely more on meaning than on enjoyment alone.