Document Type : Research Paper

Authors

Abstract

The aim of the present study was to assess how increasing fatigue in standing balance task affects performance and the variability of postural sway. Fifteen young healthy men participants were asked to stand still on a force plate after three levels (40-50%, 60-70%, 80-90% max of heart rate) of Physical Activity. As physical activity intensity increased, the amplitude of postural sway also increased. In the antero-posterior axis and medio-lateral axis Fuzzy Entropy (variability) of postural sway decreased from the stable condition to three level of physical activity condition. Lower values of Fuzzy Entropy in postural sway during stable condition correlated with greater percent increases in postural sway in medio-lateral and antero-posterior axis from the standing still condition to the highest level of physical activity intensity condition. With fatigue, The structure of variability move to less flexibility And it makes the system less flexible and environmental constraints limited duty to adapt their show lower and decrease the performance qualitative level of postural control task.

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