Different verbal instructions concerning attentional focus did not influence quiet standing control in healthy young adults

BACKGROUND: The instructions given to the participant before postural control assessment are often mentioned as possible factors of influence on the stability outcomes. However, in young adults without impairments that affect postural control, such influences are likely to be neutral. AIM: This study investigated the influence of different verbal instructions, intended to elicit either an external or internal focus of attention, on postural control metrics during a common quiet standing task in young adults. METHODS: Thirty participants performed 30-s quiet standing trials while center of pressure (CoP) was recorded under different instructional conditions: a control condition with no instruction (always the first trial), an internal focus condition, an external focus condition, and a combined focus condition (both internal and external focus command). RESULTS: No significant effects of instructions were found for center of pressure outcomes (area of an ellipse involving 95% of CoP data, resultant velocity and the anteroposterior and mediolateral amplitudes of displacement). The different attentional foci during the quiet standing did not influence the postural stability of young adults. INTERPRETATION: We interpret these findings as suggesting that in youg adults there might be no concern about the verbal instruction delivered before assessment of postural control during quiet standing.