Abstract
Ageing impacts on the ability to aim accurately towards a goal. As a result, older adults generally slow down their hand movement and make more corrections to ensure endpoint accuracy. However, previous research has shown that 1) these age-related changes do not occur in older adults maintaining high levels of physical activity, and 2) the control of eye movements does not seem to be affected by age. Therefore, it remains unclear how age and physical activity level affect eye-hand coordination during manual aiming. To tackle this question, four groups [1) active young, 2) sedentary young, 3) active older, and 4) sedentary older adults] were asked to move a cursor as fast and accurate as possible towards a target (index of difficulty: 6.2). Eye and hand-movement kinematics were analyzed to investigate coordination differences. The use of eye movements did not differ among groups: the distance travelled by the primary saccade and the number of corrective eye movements appeared equal (both p > .05). In contrast, particularly age had a clear impact on hand movement execution: despite longer reaction and movement times (both p < .01), older adults demonstrated slightly lower accuracy rates (p < .05). They also moved slower than young adults (p < .05) and used more corrections (p < .01). Interestingly, most of these age-related changes disappeared when the active older sample was compared only to the sedentary young subgroup. The latter result underpins the importance of physical activity level in daily life activities such as goal-directed aiming.
