The purpose of this study is to examine the impact of a combined cognitive training and aerobic exercise intervention in sedentary older adults. It is hypothesized that the aerobic exercise will potentiate and increase the generalizability of the cognitive training. Importantly, this study will focus on older adults at-risk for mobility disability. This area is of particular importance considering a large percentage of adults are entering old age and therefore likely to suffer from age-related cognitive decline and mobility disability.