The aim of this article was to question the classical inverted-U curve relationship between activation and performance. It was hypothesized that changes in performance were related to both activation and the degree of skill difficulty, suggesting a more complex relation. Fifty-one subjects took part in one of three experiments requiring sensory and motor anticipation abilities. They were divided into three different groups, each performing one particular anticipation task. Skin resistance was continuously recorded during task performance. This autonomic variable is well known to be a reliable index in predicting activation variations. The first task, carried out in a seated position, was to intercept a moving spot on a computer screen by pressing the space bar on the keyboard. The second task, performed standing, required subjects to intercept a moving table tennis ball with palm of the hand, by extending the forearm and the arm. The third task, executed in movement was performed on a volley-ball ground. The aim was to hit a ball to reach a moving human target, using the forearm-blow technique. Results showed that 90.9% of subjects'performance in Experiment 1 was related to skin resistance tonic level variations, thus establishing a strong relationship between performance and arousal. Subjects' performance (43.8%) in Experiment 2 was related to skin resistance tonic level variations, whereas only 12.5% of performance was related to this variable in Experiment 3. In conclusion, tonic level variations can only account for success or failure in the first experiment. Conversely, success or failure were dependent upon information processing, decision making, and motor execution in the third experiment. The second experiment, requiring intermediate abilities, was found to show intermediate results. The role of skin resistance tonic level fluctuations and their use in the study of sporting performance are discussed, suggesting that arousal/performance relationships do not correspond to a simple inverted-U curve in complex motor skills requiring a steady level of arousal.