The effects of interpersonal development programmes with sport coaches and parents on youth athlete outcomes: A systematic review and meta-analysis.

Interpersonal coach-and parent development programmes (CDP and PDP, respectively), have the goal to foster positive youth sport experiences through high-quality relations between coaches, parents, and youth athletes. In this paper we systematically review the extant literature and estimate the overall magnitude of such programmes and how they can inform future interventions. Specifically, we aimed to: (a) conduct a systematic review on the literature of interpersonal CDPs and PDPs within the youth sport context; (b) examine the effects of such interventions on youth athlete outcomes via a meta-analysis. English written peer-reviewed publications and grey literature was identified through electronic search in databases and manual searches of reference lists. By utilising a priori criteria for inclusion and exclusion, 33 studies describing interpersonal CDPs, and PDPs were identified in the systematic review. Studies that presented required data for estimation of Hedge's g effect sizes were included in the meta-analysis (k = 27). By and large, the included studies used a quasi-experimental design (58%), sampled from team sports (79%), and reported several delivery methods (e.g., workshops, audio feedback, observations, peer group discussions) and outcome measures (e.g., anxiety, autonomous motivation, self-confidence). Some interventions were based on the same delivery protocols (e.g., Coach Effectiveness Training, Mastery Approach to Coaching) or theoretical frameworks (e.g., Achievement Goal Theory, Self-Determination Theory). The meta-analysis showed statistically significant small, and medium, effect sizes on a subsample of youth athlete outcomes (e.g., task-related climate, fun and enjoyment, anxiety), indicating that coach interpersonal skills can contribute to positive youth sport experiences. Theory-based interpersonal CDPs and PDPs are recommended to expand the knowledge in this field of research.