Individual psychological characteristics in performance settings: understanding processes and developing assessment tools

High-performance settings, such as sport and work, are characterized by continuous demands for achievement, adaptability, and sustained engagement. In these environments, researchers have long focused on identifying and understanding the individual psychological characteristics that enable people to function effectively, stay motivated, and preserve well-being under performance pressure. Understanding how these characteristics operate, interact, and can be strengthened has therefore become a central focus for both disciplines. Building on this perspective, the present doctoral thesis explores how positive individual characteristics foster engagement, persistence, and performance within high-performance environments. Each study focuses on a positive individual characteristic or set of characteristics examined in either sport or work contexts, with the overarching aim of advancing understanding of how these resources support sustainable performance and well-being in demanding settings. The first chapter, Playful Sport Design among Young Soccer Players: A Diary Study Exploring Links with Sport Engagement and Performance, examines Playful Sport Design (PSD) as a self-initiated strategy through which athletes introduce elements of fun and challenge into their daily practice. Using a daily diary design, it investigates the association between PSD and sport performance through the mediating role of sport engagement. The second chapter, Linking Self-Efficacy to Dropout Intentions in Youth Soccer: The Role of Engagement and Coaching, adopts a multilevel design to analyze how self-efficacy relates to dropout intentions via sport engagement, and how empowering and directive coaching styles shape this relationship. The third chapter, The Work Agency Situational Judgment Test (WA-SJT): A Preliminary Validation of a Scenario-Based Test, extends the investigation to the organizational domain, presenting the development and preliminary validation of a situational judgment test designed to assess three interrelated facets of agency at work, hope, emotional self-regulation, and proactivity.