1, the essentials of floating ball jumping

Drive the forearm with the big arm, and the forearm hits the middle and lower point of the ball with the back of the hand. When knocking down the ball, the arms and hands need to stop and freeze, so that the ball can be stressed instantly, and the ball can jump up and float without rotating. When serving volleyball, the hand shape is five fingers together, with a slight gap in the palm and an arc shape. If the volleyball floats out in a high arc, it drops sharply when it lands.

2. Causes of Drift Ball

Non-rotating objects flying in the air, because there is no axis of rotation, their flight trajectory is unstable and easy to swing. When hitting the ball, due to the concave deformation of the hit part of the ball, the gas pressure in the ball increases, making other parts of the ball convex deformation.

When these parts of the sphere return to their original shape, the interior of the sphere impacts the depressed and deformed parts of the sphere at high speed, but the depressed parts go beyond the original shape and become new protrusions, resulting in reverse deformation, thus repeatedly forming vibration. At the moment of vibration, the sphere has lost its normal shape, thus drifting under the action of aerodynamic force.

Volleyball drift technology;

1, the definition of floating ball

A ball that floats in the air without rotating is called a floating ball, which is mainly seen in serving. The drifting performance of the float ball in flight makes it difficult for athletes to judge, so it can increase the difficulty of receiving the serve, which is one of the commonly used serve techniques. Phenomenologically, the trajectory of the floating ball is similar to periodic oscillation, or it moves in a way of sudden stall and sag, rather than along a parabolic trajectory.

2. Sink the floating ball

When the speed of the ball drops to 5 to 10 m per second in flight, the ball will be subjected to strong air resistance nearly twice the speed of the ball, and the ball will produce obvious lateral force, which always exists during the flight of the ball, but is particularly strong at a specific speed, and then the ball will suddenly stall, and naturally form a sinking floating ball under the action of gravity.

3. Method of action

Take the right hand as an example. Facing the net, players naturally spread their feet back and forth, with their left feet in front and their left hands holding the ball in front. They lifted the ball up with the flat support of their arms and palms, and threw it smoothly and vertically in front of their right shoulders, slightly lower in height. While throwing the ball with your left hand, raise your right arm, bend your elbow and pull it back, with your elbow flush with your shoulder, and turn your upper body slightly to the right. Before hitting the ball, swing your arm straight from back to front.