Effects of age and step direction on behavioral performances and center-of-pressure characteristics of volitional stepping in older and young adults

This study investigated center-of-pressure (COP) characteristics during volitional stepping in forward, backward, and sideways directions, along with the behavioral performance measures and COP measures of volitional stepping in these directions, and the relationships between these two types of measures in healthy older and young adults. Fifteen older and 15 young adults performed rapid stepping in the three directions using each leg. Behavioral performance measures included reaction time (RT), movement time (MT), step length, and step velocity in the MT phase. COP measures included the maximum anteroposterior (COPAP) and mediolateral COP displacement (COPML) in the RT phase. Stepping in each direction demonstrated unique COP characteristics. The older adults presented slower RT, MT, step velocity, and smaller COP AP in all three stepping directions (p < 0.05), as well as smaller COPML in the sideways stepping direction (p < 0.017), compared to the young adults. Step velocity correlated with COPAP and/or COPML in all three stepping directions for both groups (r = 0.420.77, p < 0.05), suggesting that stepping performances during the movement execution phase correlated with COP control during the postural preparation phase. Results suggest that stepping training prescribed to older adults to improve their balance control may include multi-directional stepping. ? 2012 National Taiwan University.