Gait and its components in typically developing preschoolers.

The objective of this study was to determine whether key spatio-temporal components of gait can be identified in children who are preschoolers. Subsequently the obtained components were correlated to results of functional balance tests to determine which of them are related to balance control.

Thirty-three typically developing children performed gait on treadmill at three speeds (range 2-4.5km/h), the Pediatric Balance Scale (PBS) and the Timed Up and Go test (TUG). Principal component analysis (PCA) with varimax rotation was performed to detect relations between means and variability of step time, -length and -width, walking speed, age, BMI and leg length. Pearson correlation coefficients between the principal components and z-scores of the PBS and TUG were calculated.

PCA revealed three principal components. The first component, maturation, showed high loadings for mean step length (0.911), age (0.897), walking speed (0.895), leg length (0.874) and step time variability (-0.672) explaining 37.57% of the variance. The second component, variability of gait, loaded with step length variability (0.819) and step width variability (0.818), explaining 18.02% of the variance. The third component, robustness, showed high loadings for mean step time (0.729), BMI (0.668) and mean step width (0.521), explaining 13.89% of the variance. A significant weak correlation was found between robustness and z-scores of the PBS (r=0.230, p=0.005). It seems that the key spatio-temporal component robustness is complementary to functional balance tests, suggesting its relevance in the assessment of balance control in preschoolers.