The relationship between fear of falling and human postural control.

This study was designed to improve the understanding of how standing at elevated surface heights and the associated changes in the visual field affect human balance control. Healthy young adults stood at four different surface heights (ground, 0.8, 1.6 and 3.2 m) under three different visual conditions (eyes open, eyes closed and eyes open with peripheral vision occluded). Mean position, Mean Power Frequency (MPF) and Root Mean Square (RMS) of centre of pressure (COP) displacements were calculated from 60s standing trials, and psychosocial and physiological measures of fear and anxiety were also collected. When standing at a height of 3.2 m, 10 of 36 participants reported an increase in anxiety and a robust fear response while the remaining 26 participants experienced only an increase in anxiety and no fear response. A between subjects analysis of the effect of surface height on postural control revealed that fearful and non-fearful participants adopted different postural control strategies with increased heights. Non-fearful participants demonstrated a postural response characterized by increased MPF and decreased RMS of COP displacements with increasing heights. In contrast, fearful participants demonstrated both increasing MPF and RMS of COP displacements with increasing heights. These findings demonstrate, for the first time, a direct relationship between fear of falling and the strategies used for human postural control.