The U-shaped effect of coach-athlete attachment on athlete engagement: the mediating role of thriving and the moderating role of mental toughness

Based on the Conservation of Resources Theory and Affective Information Theory, this study explored the impact of coach-athlete attachment on athlete engagement, its underlying mechanisms, and boundary conditions from a "loss-gain" dual-path perspective. Using the Coach-Athlete Attachment Scale, Thriving Scale, Athlete Engagement Scale, and Mental Toughness Scale, a cross-sectional survey was conducted with 424 athletes (299 males, 125 females, mean age = 16.14 ± 2.24 years) from different regions, using a convenience sampling method. The results showed that coach-athlete attachment and its subdimensions (avoidant attachment and anxious attachment) exerted a U-shaped influence on thriving and athlete engagement, with an asymmetric U-shaped curve, where the left path is longer and the right path was shorter. Thriving significantly positively influenced athlete engagement and serves as an instantaneous mediator in the U-shaped relationship between coach-athlete attachment and athlete engagement. Mental toughness significantly moderated the U-shaped effect of coach-athlete attachment on thriving and athlete engagement. The findings encouraged coaches to thoughtfully consider athletes' attachment tendencies and adjust their communication strategies based on athletes' attachment types to enhance athletes' thriving and engagement levels.