Dual-Tasking in Older people

751 Trips are a commonly reported cause of falls and are reported to contribute between 35% and 53% of falls in older people (1,2). poor lower limb strength as suggested by poor leg press push off force (3), fast walking speed prior to crossing an obstacle (4), and delayed support limb loading (4) are associated with a greater risk of falling following an obstacle contact in healthy older adults. Delayed lower extremity muscle activity onset and reduced amplitude of muscle responses (5), as well as visual factors such as refractive blur or the wearing of multifocal glasses (6–9) have also been implicated in obstacle contacts in healthy older adults. The generalizability of these findings is limited in that they relate only to the crossing of a single obstacle or step, either already present in the path or appearing suddenly. in everyday life, when older people navigate in a challenging and distracting environment such as a shopping mall or busy street, they might have to avoid ground level obstacles when their attention is divided. in this instance, obstacle negotiation performance is likely to be further impaired as revealed by most dual-task studies involving older adults (10–12). To date, no studies have examined the underlying physiological mechanisms that contribute to safe obstacle course negotiation in older people, either with or without the addition of a secondary task. such information is important for the selection of relevant sensorimotor screening tests to identify risk factors for trips and stumbles and prevent subsequent falls in older people. The objectives of this study, therefore, were to examine (i) the effect of a secondary visual task on obstacle contact when older people negotiated an obstacle course and (ii) physiological factors associated with obstacle course negotiation (obstacle contacts and trial time) in trials with and without the secondary task.