Moderation of sibling number on the relationship between physical activity and executive functions in children

This study aimed to investigate the impact of sibling number on the relationship between physical activity and executive functions in preschool children. Specifically, it sought to determine whether the number of sibling numbers would moderate the relationship between physical activity and executive functions.

A total of 123 preschool children aged 4 to 6 years participated in this study. The number of sibling was investigated using a questionnaire (only child n=21, non-only child n=102). Physical activity was objectively measured using the ActiGraph wGT3X, while executive functions were evaluated using the Go/No-Go task (inhibitory control), digit span task (working memory), and card sorting task (cognitive flexibility). Data from 48 participants were valid for final analysis. The moderating effect of sibling number on the relationship between physical activity (i.e., light physical activity, moderate physical activity, vigorous physical activity, moderate-to-vigorous physical activity, and total physical activity) and executive functions (i.e., inhibitory control, working memory, and cognitive flexibility) was analyzed using the PROCESS macro for SPSS (Model 1), controlling for sex.

No statistically significant correlations were found among sibling number, physical activity, and executive functions. However, out of 15 tested moderation models, sibling number significantly moderated the relationship between vigorous physical activity (VPA) and working memory (p = 0.0475). Moreover, there was a marginally significant moderating effect of sibling number on the relationship between moderate-to-vigorous physical activity (MVPA) and working memory (p = 0.0726). These results suggest that preschool children with fewer siblings showed improved working memory with high levels of MVPA and VPA. In contrast, those with more siblings exhibited poorer working memory with increased MVPA and VPA.

Our findings indicate that high intensity physical activity, specifically VPA, positively influences working memory in preschool children with fewer siblings. However, children with more siblings may not experience the same cognitive benefits from engaging in VPA, challenging our initial hypothesis.

This study provides insights for family-centered intervention. Health professional could develop strategies to enhance young children’s executive function through physical activity, taking into account the number of siblings in a family.