This study assessed the impact of body mass index (BMI) and socioeconomic status (SES) on the Zurich Neuromotor Assessment, second version (ZNA-2), a battery of tests of motor development in typically developing children between 3 and 18 years of age. BMI measurements and international socio-economic index data were taken from the normative sample of the ZNA-2 for 321 children (158 boys, 163 girls) with a median age of 9.3 years. The age- and gender-adjusted motor performance of these children was quantified and grouped into five components: fine, pure, and gross motor tasks, static balance, and contralateral associated movements. A total score was also calculated. The associations of BMI and SES with the motor scores contribute to less than 5.1% of the total variance.Conclusion: The ZNA-2 for motor development is suitable for measuring motor abilities' development as it is largely independent of the BMI of the child and the SES of the family. What is Known: • Typical motor development, as measured with the Zurich Neuromotor Assessment, second edition (ZNA-2), is strongly dependent on age and gender. • The ZNA-2 focusses on motor performance, motor quality and simple motor skills. What is New: • Higher socio-economic status (SES) is associated with slightly better motor performance as measured by the ZNA-2 total score. • In the ZNA-2 less than 5.1% of the variability in motor performance is attributable to the combined effect of body mass index and SES.
Keywords: Body mass index; Gender; Motor performance; Socio-economic status; Typical motor development.