Does load carriage differentially alter postural sway in overweight vs. normal-weight schoolchildren?

Among a wide range of negative consequences stemming from excess mass in children, recent studies suggest an impairment of postural control, including basic capabilities such as static and dynamic balance. Such impairment may be compounded when additional tasks are performed, such as carrying localized loads as occurs among children using a backpack. To investigate this, postural control was measured among 77 overweight and obese children (6-11 years old), and an equal number of normal-weight children matched for gender, age, and height. Testing was conducted at school, in which center of pressure (COP) time series during quiet standing were obtained in the presence and absence of each student's backpack. A traditional postural control measure derived from COP (mean velocity) did not indicate significant differences between overweight and normal-weight children, regardless of backpack presence. In contrast, a complexity index (derived from multiscale entropy) suggested the existence of different postural strategies and reduced balance capabilities among overweight children, whose consequences need to be further clarified.