Introduction: The aim of this study was to describe two strokes : the top spin rotation and the striking top spin. The study includes an analysis of the movement, and the study of relative and temporal structures such as those developed in the centro-peripheral theory (Schmidt R.A., 1975, Psychological Review, 82(4), 225-260). The goals were to create patterns of profiles, to create a 2D representation of the two strokes, and to study the motor control. The hypothesis being that it was in reality a gesture with variations which means that these two gestures belong from the same generalized motor program (PMG). Methods: Eight players participated to the study, all of them were members of the Senior French team : 3 were classified among the best 100 table-tennis players, five were classified between the 100th and the 300th. During a ball distribution while training, they realized a pseudo-random series composed of 20 tops spin rotations and 20 striking ones. We collected the data (on arm and racket) on video. Only the tests included in the confidence interval at 95% of the normal law which represents the distribution (Shapiro and Wilk`s test : P<.05) on two variables of the trajectory (distance bounce/net, bounce height) were being considered. The video data have then been digitized (25Hz) and studied frame after frame. The articulations (elbow and shoulder) and the tip of the racket have been indicated on each frame and have been transformed into figures which have been used to the 2D reconstruction and to the study of stages, thanks to a software programme (3Clic 2.0.0©). Results and Discussion: The major results are that the relative temporal structure is identical, so it seems that these two strokes come from the same PMG. The vertical stretch (Bottom/Top) is a surface characteristic which distinguishes these two strokes whereas the anteroposterior stretch is identical. The individual observation of the representations shows a tendency to go further forward and less upwards for the striking top-spin, which is in harmony with the ground discourse. The two forms of movement, according to the strokes, differ one from the other much later. The form doesn`t seem to be at the source of the differentiation of the two strokes, neither does it produce more efficiency. The change in the form between the two is often minimal and takes place between the impact and the end of the movement. A dominant pattern profile appears but counter examples also appear, so the results must be relative. As a matter of fact, the dominant profile consists in the minimal modification of the gesture and as a result there is a decreasing quantity of information given by the opponent but maybe to the prejudice of efficiency. It is worth observing that the most untypical concerning the organization are the best classified. These players belonging to the world-wide 100 top keep the same temporal structure which is relative when slightly modifying the striking top spin form and the rotation top spin in order to preserve the highest efficiency (with the possibility for the opponent of limited information), on the other hand, our results show the left-handed players mask their strokes in a more performing way and differentiate their strokes later on. If we consider the practical side, this study shows the importance a) of the combined approach of the two tops spin as soon as possible while learning (as soon as the control has reached the motor level), and b) to focalize the player`s attention on the ball`s action and on where the ball has its impact that are the tops spin` main elements.
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