The influence of gender and body characteristics on upright stance.

BACKGROUND: Morphologic characteristics such as height and body weight determine body inertia, an important factor related to postural stability. However, whilst investigations have classically analysed these parameters separately, global morphology has been poorly researched. Secondly, the influence of gender on postural stability demonstrates opposing trends, some authors observing that men sway less than women, and others noting the contrary. AIM: The aims of this study are to evaluate morphology and gender effects on healthy subjects during postural maintenance. SUBJECTS AND METHODS: The studied subjects were categorized through the Livi index. A method associating frequential and Brownian parameters characterized the horizontal displacements of the centre of gravity (CG(h)) and those of the difference between the centre of pressure (CP) and the vertical projection of the centre of gravity (CP-CG(v)) separately. Moreover, the moments of body inertia (MI) and natural body frequency (NBF) were also used to determine the influence of morphology. RESULTS AND
CONCLUSIONS: The results reveal that thinner subjects have larger CG(h) displacements than normal or corpulent subjects. Morphologic characteristics (NBF) can explain these behavioural differences. On the other hand, men have a larger sway amplitude for CG(h) motions than women. This can be explained by both morphologic (MI, NBF) and physiological (architectural properties of the soleus muscle) characteristics.