Abstract
<title>Abstract</title> <p>Background Field based physical fitness tests are widely used to describe motor performance in school age children, but the motor and anthropometric correlates of change of direction tasks during late childhood remain incompletely described. The 505 change of direction (COD) test captures a pre planned movement task that requires acceleration, deceleration, turning, and reacceleration. This study examined motor performance and field based physical fitness correlates of 505 COD performance in 9 to 10 year old children. Methods This exploratory cross-sectional study included 98 apparently healthy school age children (55 boys and 43 girls). The 505 COD time was used as the outcome variable. Candidate field based variables included 20 m sprint time, back leg strength, handgrip strength, squat jump, simple visual reaction time, flexibility tests, and selected anthropometric indices. Sex stratified correlations were interpreted with Benjamini-Hochberg false discovery rate (FDR) q values. Exploratory regression models were intentionally conservative and should be interpreted as within sample explanatory models rather than validated prediction tools. Results Across boys and girls, 20 m sprint time was the most consistent correlate of 505 COD time. In boys, the model including 20 m sprint time and back leg strength explained 39.8% of the variance in 505 COD time (adjusted R2 = 0.375). In girls, the conservative model including 20 m sprint time and simple visual reaction time explained 58.9% of the variance (adjusted R2 = 0.568). A sensitivity model including shoulder hip ratio explained 63.3% of the variance but was interpreted cautiously because shoulder hip ratio was not a significant bivariate correlate of 505 COD time. Conclusions In school age children, linear sprint performance was the most consistent field based correlate of 505 COD performance. Strength related measures in boys and general neuromotor response time in girls provided additional explanatory information, but the findings are exploratory. The models should not be used as clinical, screening, or individual level prediction tools without further validation in larger pediatric samples with maturation, habitual physical activity, sport participation, and reliability data.</p>