Sex differences in postural control under unstable conditions in schoolchildren with accelerometric assessment

Abstract

Background: Although the effects of balance training on unstable surfaces have been widely studied, the impact of exposure to an unstable surface in static balance throughout childhood has not been described to date.

Research question: How does postural stability vary between sexes in children 6-12 years of age during single leg static support on unstable surface? What are the normative values of centre of mass acceleration in the mentioned age range during such test? Is the postural stability on an unstable surface in the postural control of children aged 6-12 years during static single-leg stance. Secondarily, the normative acceleration values of the gravity centre, recorded during such tests and throughout the mentioned age range, were also provided.

Methods: Descriptive, transversal study conducted with a total of 316 school children (girls = 158). The analysed variables were the mean and maximum values obtained in each of the three body axes and their root mean square during static single-leg support test on an unstable surface (a mat).

Findings: Accelerations decreased in magnitude with the increasing age of the participants. The highest accelerometric values were recorded in the medio-lateral axis in both sexes and throughout the entire age range studied. Between sexes, the greatest differences were obtained between 8 and 11 year-olds. The regression models revealed significant values about the influence of sex on the accelerometric variables (girls were more likely to obtain less accelerations in postural adjustments with increasing age).

Interpretation: Boys depend more on somatoaesthetic information, whereas girls would use more visual and vestibular information. In the age range of 8-11 years, the postural control system is significantly different between sexes regarding the hierarchy of the efferent information of the available postural control subsystems. Moreover, the reactions of straightening and postural control on single-leg stance are, fundamentally, flexion-extension movements.

Keywords: Accelerometer; Biomechanical phenomena; Child development; Postural balance; Sex characteristics.