Physical fitness factors associated with change-of-direction performance in primary schoolchildren: the role of muscular strength, flexibility, and sex

Abstract

Change-of-direction (COD) performance is an important component of motor performance during childhood and depends on multiple physical capacities. However, the associations of muscular strength, muscular endurance, and flexibility with COD performance, and the potential moderating role of sex, remain insufficiently understood in school-aged children. This cross-sectional study included 386 primary schoolchildren (176 boys and 210 girls; mean age: 11.15 ± 0.66 years). Handgrip strength, lower-body explosive strength, trunk muscular endurance, flexibility, and COD performance were assessed using handgrip dynamometry, the standing long jump, 30-s sit-up, sit-and-reach, and 4 x 10-m shuttle-run tests, respectively. Sex differences were examined using independent-samples t-tests. Pearson correlations and hierarchical multiple linear regression analyzes examined associations with COD performance, with interaction terms used to assess moderation by sex. Not statistically significant Differences between boys and girls were detected in physical fitness components or COD performance (all p > 0.05). COD performance was significantly associated with lower-body explosive strength (r = −0.775), handgrip strength (r = −0.706), flexibility (r = −0.534), and trunk muscular endurance (r = −0.532) (all p < 0.001). After adjustment for age, sex, and BMI, physical fitness components increased the explained variance in COD performance by 61.4% ( Δ R 2 = 0.614, p < 0.001), with the final model explaining 62.6% of the variance. Lower-body explosive strength showed the strongest independent association ( β = −0.566, p < 0.001), followed by handgrip strength ( β = −0.180, p = 0.003) and flexibility ( β = −0.111, p = 0.005). Trunk muscular endurance was not independently associated with COD performance ( β = 0.007, p = 0.878). Sex did not mean anything moderated these associations ( Δ R 2 = 0.003, p = 0.632). Physical fitness, particularly lower-body explosive strength, was strongly associated with COD performance in primary schoolchildren. Handgrip strength and flexibility showed smaller independent associations, considering trunk muscular endurance did not after simultaneous adjustment for other fitness components. No significant between sex differences or moderating effects of sex were detected.