Perceptual-motor planning and performance in dynamical postural control

The main aim of this dissertation is to obtain a deeper understanding about the dynamics of postural control in human movement. In particular here we approach the problem by including several motor tasks and by testing different populations in three separate studies. The first one deals with the action of climbing stairs. In this experiment the populations tested were old and young adults and the main aim was to reveal whether there are different perceptive/motor postural strategies either for planning as well as for executing the action due to the decrease of the level of motor skill. The other two studies instead focalize more the attention on the development of postural adjustments, before and during the action performance, when the level of motor skill reaches its optimality. In these latter two cases the populations tested were elite athletes performing actions in which they excel, and as a consequence the aim of these studies was to reveal how excellence merges from the developments of specific muscular synergies due to practice. Even though the three experiments share issues related to the dynamics of postural control, different models and theoretical frameworks inspire each one. On the one hand, we refer to the concept of movement “equifinality” formulated by Nicolay Bernstein (1967) and to the concept of “affordance” formulated by J.J. Gibson (1979). These two ideas taken together inspired the first study presented. On the other hand, the law formulated by Paul Fitts (1954) inspired the latter two experiments. In the introduction we will present in sequence these ideas and their relative models: first equifinality, followed by affordance, and then Fitts’ law. Since these three theoretical concepts are applied to the dynamics of postural control, a final chapter will discuss more in depth issues related to the control of posture. Then the three experiments will be presented.