, 2000 ). From a control perspective, it can be stated that changes in central commands did this not lead to changes in APA time in the analyzed motor task. Therefore, one should remember that it was a rapid movement which differs from cyclic ones. However, Winstein et al. (1997) found that in classical tapping tasks, when more precise targeting independent of task difficulty was required, a cortical-subcortical loop composed of the contralateral motor cortex, intraparietal sulcus and caudate was much more activated. They showed, with a use of positron emission tomography (PET), that greater effort in performing a difficult task (smaller targets) recruits more motor planning areas. Recent studies showed that there is a specific modulation of neural network associated with the availability of time to plan the upcoming movement and motor difficulty.
One of them used brain-imaging (fMRI) to examine a simple motor task – moving a mouse cursor on a screen ( Boyd et al., 2009 ). Another examined step initiation in patients with Parkinson��s disease ( Jacobs et al., 2009 ). The same concerns the study by Bartucco and Cesari (2010) described earlier, which focused on motion capture experiments on ballet movements. It looks like in these experiments subjects used distinct control of APA duration and APA magnitude according to Fitts�� law. It is one of the limitation of our study that we did not observe changes in the central nervous system. An additional limitation is that we did not record muscle activity.
It is hard to estimate information processing but it can be guessed that the commands do not concern speed manifested in the velocity of a dart but the accuracy of aiming. Concentrating on accuracy does not have to lead to changes in force recruitment. That hypothesis is partly supported by Smits-Engelsman et al. (2002) who suggest fundamental differences in cyclic and discrete movements. They also claim that cyclic movements make a more cost-effective use of the recruited force, use less information-processing capacity and less change in force, then discrete ( Smits-Engelsman et al., 2002 ). This interesting hypothesis is worth considering and examining in future research. Whenever we optimize the speed-accuracy trade-off in specific movement by repetitions we can create a motor skill and perform the movement better and better. Then we start to act effortless and automatic.
Unfortunately, there is a lack of data concerning some applications of Fitts�� law in sports training. It is simply impossible to say if it is better to Brefeldin_A differentiate a distance or a target size during the process of gradual mastering of specific motor skills with repeated performance. From a physics point of view, controlling velocity seems to be the simplest way to perform a motor task. It may be more effective to change spatial constraints to achieve better results in high-performance sport.