My PhD was conducted under the joint supervision of Profs. Jean-Louis Thonnard and André Mouraux. The objective of my PhD was to explore the involvement of high-level cognitive resources in the performance of a common manual behaviour. In everyday life, object manipulation is among the most common tasks we perform and is usually performed concurrently to the execution of cognitive tasks. In a recent study we show that mental resources are required for both the planning and the online control of upper-limb movement. By using a motor-cognitive dual-task paradigm, current studies will examine the influence of a cognitive task on the different aspects of precision grip in elders and in patients presenting with a peripheral or central lesion of the nervous system. Indeed, it could well be that with aging and/or following such a lesion, precision grip is even more dependent on cognitive resources.