Associations Between Fundamental Movement Skills, Muscular Fitness, Self-Perception and Physical Activity in Primary School Students

<b>Background/Objectives:</b> Positive self-perception, physical activity and fundamental movement skill (FMS) proficiency are important aspects of a child's healthy development. The objective of this research was twofold: first, to explore associations between FMS, muscular fitness, self-perception and physical activity in school children; and second, to identify key predictors of FMS proficiency, athletic self-perception, physical activity levels in these participants and the differences between biological sexes. <b>Methods:</b> Primary school-aged children (n = 104; 53.85% female) from 8 to 10 years old (M = 9.04, SD = 0.69) engaged in two days of testing. All students were measured on FMS, standing long jump (SLJ), countermovement jump (CMJ), seated medicine ball chest throw and self-perception, followed by correlation and stepwise multiple linear regression analyses. <b>Results:</b> The findings revealed significant positive correlations between FMS proficiency, lower body muscular fitness (CMJ, SLJ), and athletic self-perception for the entire cohort, with varying results between male and female subgroups. Additionally, athletic self-perception showed strong relationships with other self-perception domains. Notably, forward stepwise regression analysis identified FMS proficiency as a significant predictor of physical activity levels, explaining 12.8% of the variance. SLJ, scholastic perception, and physical activity explained 45.5% of FMS variance for females. In males, FMS proficiency significantly predicted physical activity, accounting for 13.3% of the variance. SLJ and athletic competence self-perception explained 42.1% of FMS variance in males. <b>Conclusions:</b> The study indicates that FMS, self-perception, muscular fitness, and physical activity levels may mutually enhance each other, and that there is a need for biological sex-specific strategies to be considered in physical education programs.