4: Division of the strokes according to movement rhythms
The cause is the independence of the respective horizontal velocity of the ball. If the players move away from each other, the 'catching movement' must also be adapted to the horizontal movement of the ball, with the time constancy in the vertical relations remaining the same. In doing so, the racket face can 'stick' to the ball within the direct space of movement However, as soon as it leaves this space, the longitudinal axis of the racket which points to the ball, keeps contact by means of the simultaneous drawing' of the flight curve of the ball (figure 5).
Figure 5: Half-volley - 'drawing'
The rhythm which is created by this keeping of contact, as discussed above, makes possible a controlled imparting of impulse at the moment of hitting. Even if the impulse time only lasts part of a second and no conscious movement correction is possible, the form movement of the racket face must correspond with the actual as well as with the required flight curve before as well as after hitting the ball. This is achieved by a 'guiding path' which is as long as possible. At the same time, the centre of the racket face is level with the target direction, the vertical movement regulates the height, and the inclination of the racket face influences the modulation of the ball flight. If, for example, the ball must be hit without spin, the racket face must be perpendicular to the present movement direction of the ball at the moment of hitting. Since, however, the movement of the ball changes during the movement of the racket, the inclination of the racket face must correspond with the flight curve of the ball by a rotation around the longitudinal axis. Thus, the flight curve of the ball is first of all followed and then anticipated by the 'opening' and 'closing' of the racket face.
However, the racket face is no object hanging in mid-air, but the player must set it into a corresponding motion. In doing so, he orientates his movement action (movement of the racket face) to the ball curve, in moving upward and downward to the vertical aspect, in moving to and fro to the horizontal aspect, and in changing the inclination of the racket face to the connection between the vertical and the horizontal aspect of the ball curve.
The transmitting of the ball curve via the movement of the racket face to the player's body is a grasping, a feeling, a simultaneous 'drawing' of with the player perceives of the ball curve with the aim to determine the future movements of the ball in the 'guiding movement'. This succeeds the better, the more exact this unity with the ball, the unit of perception and movement, is achieved.
1.4 Gravitation and rhythm
If the player's movement is created by the process of 'drawing' of what he sees or strives for, the movement rhythm (timing) which is created in the unit of ball and player thus described is a result of the relations made between the racket face and the ball. The ball curves, which always resemble each other, and the racket face, which simultaneously follows the ball curve, impose the movement rhythm on the player. The recurring movements of the body are similar because the body makes possible the rules which the racket face must stick to. There is a correspondence between the compulsion of the racket face to move rhythmically and the form of the movement of the whole body.
The implication of the simultaneous process of perception and movement is made possible by gravitation.
The player behaves as if he already knew what was going to happen in the future. In moving, he abandons himself to a law which he takes for granted. When moving, he trusts in the validity of the law of gravitation. This trust corresponds to a process which can be made clear by the example of dance. The dancer does not move his feet after having heard a sound or a beat of the melody, but simultaneously with this sound or musical beat. He trusts in the flow/rhythm of the melody, he takes it for granted.
1.5 Own and outside speech
Defined timing offers the possibility of influencing imagination by speech/verbal accompaniment so that a controlled movement can be learned. The invariance of movement rhythms, created by the constancy of time in the vertical aspect, makes possible a simultaneous, i.e. synchronous verbal accompaniment of the movement. In doing so, the form can be made finer by the contents of the words; moreover, the connection of the words as far as time is concerned can be followed. If one counts at the moment of ball contact (series number of strokes), one becomes conscious of the ball contact. If, on top of that, one counts the hitting points of one's partner, one also becomes conscious of the time available for the backswing and the stroke. This optimal utilization of the time available for the return of the ball according to one's objective is achieved via the contact-face form movement which must be learned. The contact-face form movement conveys the movement rhythm: timing a, time experienced A loud verbal accompaniment of the movement brings about the integration of the rythm into the movement. Contrary to thinking out loud, the spokenwords have, apart from their mental contents, a time structure.
So the simultaneous verbal accompaniment makes it possible to imagine the mental contents and the grasping of a universal phenomenon, namely gravitation, which is a part of nature and which physics expresses in terms of laws. The ambiguous unit of concentration and meditative process can be found in the spoken word. Perception as a kind af fixation (cf. C.F.v.Weizsäcker 1983) is given its identity in the simultaneous grasping of the total action.
Whereas with the beginner first of all the period for hitting ('sticking-drawing') the ball is more important in order to find the hitting point, the ball control by means of 'guiding' becomes more important after one has learned the total rhythm. But only by grasping their interrelation can the backswing and the stroke be developed to increasingly dynamic and exact movements. Hitting the ball as a point of the guiding path only has the meaningless function of revealing the physical data of the ball curve by a force vector afterwards. The biological act which is responsible for the result cannot be explained by this.
While practising one speaks and hears one's movement. If one also accompanies the movements of one's partner verbally, one helps him in timing and trains oneself in watching and grasping one's partner'' movement which determine one's future (next ball to hit). If both players (figure 6) accompany their own and their partner's movements verbally, an automatic correction of timing ('mirror image'/ model) is done by means of the synchronousness of the language ('chorus').
In both cases a continuous concentration is achieved, a flowing 'thread', which cannot be disturbed by influences outside the game. This process is responsible for creating this absentmindedness which is characteristic of all playful acts.
Figure 6 : Identity of mirror movement and synchronous speech
1.6 Freedom and compulsion
The different approach is made clear by d~veloping the success of a movement by means of the contact-face form movement of racket face and ball and not by seeking the solution by means of a phenographic movement description. While the phenographic approach is based on the belief in the existence of 'the movement' and the 'required value', our approach regards movement only as a possibility. The mov ment form is not determined by the determinism of a kybernetic system, but by the person's freedom in a situation which he is responsible for and which he nust react to. In doing so, the contact-face form movement, which must be learned, at first sight appears to be an unnatural compulsion, a compulsive movement between racket face and ball. Between racket face and ball a mathematical-physical relation is established, and straight lines, parabolas and gravitation are used in order to make the description more precise. This clearness regarding the phenographic form in connection with the purpose