Reliability and relation of autistic traits construct with self-perceived physical fitness in school students: A structural equation model proposal for a complex evaluation

The aim of this study is to identify the reliability of an adaptation of the Autism Quotient 50 instrument associated with the self-perceived physical fitness questionnaire in a structural equation model (SEM) among school students; To describe whether there is an association between autistic traits and levels of self-reported physical fitness in both sexes in this SEM. Its cross-sectional study employed a quantitative approach that included 512 young individuals aged 10 to 19 years from the southern coast of Brazil. Autism traits were assessed using the Autism Spectrum Quotient (AQ50), and physical fitness was evaluated through the Self-Reported Physical Fitness Questionnaire (QAPA). The reliability of the AQ50 was assessed by McDonald’s Omega (ω) and Cronbach’s Alpha (α) coefficients and a SEM was used to explore associations between autistic traits and physical fitness. The analysis showed high consistency (α = 0.936; ω = 0.937) to the AQ50, and too to the QAPA questionnaire (α = 0.821; ω = 0.829). The SEM revealed negative associations between autistic traits and physical fitness, with significant age-related impacts. Girls experienced more age-related changes in autistic traits and physical fitness, whereas boys showed stronger associations between autistic traits and physical fitness, with no age impact on physical fitness. The reliability statistics and initial construct validation were consistent across questionnaires AQ50 and QAPA for both sexes with reliability coefficients greater than 0.80. In addition, there is an association between autistic traits and lower self-reported physical fitness levels (general SEM β= -0.52; p = 0.001).