Validation of the Spanish version of the Psychological Flexibility Sports Scale (PFSS)

Introduction Psychological flexibility has been conceptualized as the capacity to relate to internal experiences, maintain focus on the present moment, thereby allowing individuals to act according to the context in pursuit of their goals and values. It is a psychological construct related to mental health, where there is an increasing body of research that highlights its importance in athletic performance. The Psychological Flexibility Sports Scale (PFSS) is the first psychological flexibility scale specifically designed for use in sports. It has only been validated in a limited number of cultural contexts. Concerning this, the study aims to translate the PFSS into Spanish (ES-PFSS), thereby analyzing and identifying the psychometric properties of the ES-PFSS among native Spanish athletes or those with medium to high proficiency in Spanish. Methods The sample comprised 146 participants who practiced both team-based and individual sports. (Age 33.95 ± 11.69 years, 63.014% male). Statistical analysis was performed for reliability (internal consistency and temporal stability), construct validity, and criterion validity. Results and discussion The scale was confirmed to be unidimensional through confirmatory factor analysis. Significant results were found for the evaluation of construct validity. The ES-PFSS demonstrated solid criterion validity related to other constructs of psychological flexibility and perceived athletic performance. The reliability study proved to be significant, with excellent internal consistency (Cronbach’s α = 0.937). The scale showed low temporal stability (ICC = 0.378).