Every aspect of the ball's trajectory is determined by the hand that threw it. From the instant that the ball leaves the hand, the juggler no longer has any control over the ball's path. The point of control comes while the ball still rests in the hand. The ability to watch and gather pertinent information about the juggling pattern while concentrating on the throws themselves is the primary skill to be mastered by the juggler. Each different juggling pattern has its own characteristic rhythm.
Most rhythms are even, but a few asymmetric patterns require syncopated beats.
Whether straight or syncopated, the important requirement is that the rhythm be steady. A perfect rhythm is necessary for a smooth and controlled pattern. The rhythm is established with the initial cycle and it is at this point that a steady beat is most crucial. The balls should be released from the hands at a steady rate. Depending on the difficulty of the trick, sometimes it is helpful to release the balls at a slightly faster pace than that of the actual pattern.