Analysis of handgrip strength disparities and manual asymmetry in primary school children

Hand asymmetry can be influenced by both biological and environmental factors, emerges early, and impacts motor skills and human development. Physical differences between boys and girls during childhood, such as body composition, may influence hand strength and asymmetry. Aims: This study examines handgrip strength and asymmetry in Portuguese children aged 6 to 10. Data from the RUSH project comprises 1504 children (760 girls) aged 6-10. Right-hand preference was observed in 90.9% of girls and 89.8% of boys. Manual grip was assessed using a handheld dynamometer (T.K.K. 5401). Descriptive statistics are presented as means and standard deviations. Within each sex, a one-way ANOVA was used to test for age-related differences, and the LSD test was used for post hoc multiple comparisons. All analyses were conducted using SPSS software version 29, with the significance level set at 5%. Older children were stronger in both hands (girls – preferred: F=101.682, p<0.001; non-preferred: F=100.589, p<0.001; boys – preferred: F=69.419, p<0.001; non-preferred: F=67.867, p<0.001). Significant differences in hand asymmetry were also observed between age groups in both girls (F=4.892, p<0.05) and boys (F=7.764, p<0.05). Specifically, it was found that girls aged 6 and 10 and boys aged 10 had higher asymmetry values than those aged 6, 7, 8, and 9. Hand strength and asymmetry appear to change with older children showing greater discrepancies between preferred and non-preferred hands. Further studies are required to understand the mechanisms behind these differences.