The use of interaction tools in modern work often challenges the human
motor system, especially when these tools create awkward postures and discomfort (e.g., mouse arm syndrome). The question whether the trackball is a serious
alternative to the mouse was evaluated in this experimental study in terms of motor performance, usability and comfort. In an applied pointing-selection task we varied gain and task difficulty. Results showed a considerably stronger impact of gain and task difficulty on the trackball than on the mouse, especially for the high gain trackball performance slowed down. Second, usability ratings were significantly better for the mouse than for the trackball (independent of the experimental condition). Finally, while the discomfort after mouse usage rose notably, trackball usage led to an even bigger increase in perceived discomfort