Abstract
Aging influences our ability to aim accurately towards a goal. During discrete manual aiming, older adults are thought to ensure endpoint accuracy by applying a play-it-safe strategy. This strategy is characterized by a relatively short and slow primary submovement, and a longer subsequent corrective phase. Nonetheless, the implementation of this adapted strategy was expected to be less evident in older adults maintaining high levels of physical activity. To investigate this hypothesis, we analyzed the kinematics of eye and hand movements during aiming tasks in young adults (22-26 years old), physically active (60-68 years old) and inactive older adults (60-69 years old). Though all groups showed similar levels of endpoint accuracy, aiming strategies differed significantly. As expected, the time-consuming play-it-safe strategy was found in inactive older adults only. More specifically, they made smaller primary submovements, had lower hand peak velocities, and spent more time in the corrective phase of the movement (all p<0.01). In contrast, active older adults used a strategy similar to young adults. Interestingly, age-related effects were found in eye-movement data, such as a higher number of corrective saccades in older adults (p<0.05). Overall, these results highlight possible beneficial effects of physical activity on manual aiming and suggest that the age-related adaptation in aiming strategy can be countered (or at least postponed) by having a physically active lifestyle.
