Digital Scaffolding for Self-Regulation: How WhatsApp Reminders Potentiate MCII to Boost University Students’ Sport Self-Efficacy Beliefs

Participation in non-professional sports during the pivotal lifespan stage of young adulthood is essential for establishing a trajectory of long-term health and holistic well-being. As a foundational psychological driver, self-efficacy critically governs both the adoption and sustained persistence of physical activity. Grounded in the principles of self-regulation theory, this experimental study interrogated the efficacy of Mental Contrasting with Implementation Intentions (MCII), implemented either as a standalone protocol or augmented with WhatsApp reminder prompts, in enhancing university students’ self-efficacy for engagement in structured court tennis training. Twenty-two volunteers were randomized to an MCII-only group ( n  = 13) or an MCII-plus-reminders group ( n  = 9). Self-efficacy was measured before and after a tennis instructional period using the General Self-Efficacy Scale. Nonparametric analyses detected no significant within-group improvements. However, the magnitude of change in self-efficacy (posttest–pretest) was significantly greater in the digital reminder–augmented condition than in the MCII-only condition. The findings extend current understanding of digitally scaffolded self-regulation by demonstrating that integrating structured planning with strategic digital reminders can meaningfully enhance adolescents’ self-efficacy for sustained sport participation.