Older adults prioritize postural stability in the anterior-posterior direction to regain balance following volitional lateral step

Background: Postural control in the medial-lateral (ML) direction is of particular interest regarding the assessment of changes in postural control, as it is highly related to the risk of falling. Objective: To determine the postural strategies used to regain balance following a voluntary lateral step and compare these strategies between young and older adults. Methods: Sixteen older adults (60-90 years) and 14 young adults (20-40 years) were asked to stand quietly for 30 s, walk in place and then take a lateral step and stand quietly (30 s). Balance Post was divided into 10 s intervals. Center of pressure displacement (CoP) and velocity (VCoP) in the anterioposterior (AP) and ML directions were analyzed. Results: In both groups, CoP and VCoP in AP and ML increased in Post1 compared to Pre (P < 0.001). Dissimilar to young adults, VCoP-Post2, Post3 ML were larger than Pre (P = 0.01) in older adults. Age correlated with all VCoP (Pre and Post) in both ML (P < 0.05) and AP directions (P < 0.01). Conclusions: Dissimilar to young adults, older adults use different postural strategies in ML and AP directions and prioritized postural stability in the AP direction to recover balance after completing a lateral step. In the ML direction, older adults took up to 30 s to regain balance. Considering that age was related to larger CoP displacement and velocity, the AP strategy to recover postural balance following a lateral step could become less efficient as older adults age and therefore increasing the risk of falls. (C) 2015 Elsevier B.V. All rights reserved.