How AI coach voice anthropomorphism influences exercise adherence: A PLS-SEM and fsQCA analysis

AI coaches are increasingly used in exercise settings, yet the mechanisms linking their design features to exercise adherence remain underexplored. This study examined whether voice anthropomorphism in AI coaches is associated with exercise adherence through trust in the AI coach, social presence, perceived coaching support, and self-efficacy. Using cross-sectional survey data from 572 users with recent experience of AI coach-assisted exercise training, we employed partial least squares structural equation modeling (PLS-SEM) to test net relationships and fuzzy-set qualitative comparative analysis (fsQCA) to identify configurational paths. The results showed that voice anthropomorphism was positively associated with trust in the AI coach, social presence, and perceived coaching support. In turn, trust, social presence, and coaching support were positively related to self-efficacy, while trust, coaching support, and self-efficacy were positively associated with exercise adherence. Coaching support showed the strongest association with self-efficacy, and self-efficacy was the strongest direct correlate of exercise adherence. Mediation analyses indicated that the indirect association through coaching support and self-efficacy was the strongest. fsQCA further showed that no single condition was necessary for high exercise adherence and that multiple combinations of conditions could be associated with the same outcome. This study contributes by extending voice anthropomorphism research to AI coach-assisted exercise adherence, identifying trust, social presence, coaching support, and self-efficacy as key psychological mechanisms, and showing through PLS-SEM and fsQCA that exercise adherence is shaped by both linear net relationships and configurational pathways.