Volleyball is one of the most popular ball sports. It consists of two teams of six players standing opposite each other separated by a net. Each team tries to score points against the opposite team. At the end of the game, the team with the maximum scores is declared the winner. The game gets initiated with a volleyball serve that can be performed in a variety of ways. It can be done with a jump or while standing still. Also, the player can serve the ball overhand or underhand. The float serve is one of the most common and preferred techniques of volleyball serve and is most frequently used to initiate the game. The benefit of using the float serve is that it causes the ball to deviate from the original path and alter its direction of motion mid-way. This makes it difficult for the opposing team players to judge the location where the ball might land thereby, increasing the chances of getting a point. For the most optimal volleyball serve, the player must make a proper balance between the strength and the technique applied. Also, proper coordination between different body parts of the player such as eyes, hands, legs, etc. should be maintained. Various physical parameters to be taken care of during a volleyball serve are torque, the centre of mass, angular momentum, linear velocity, momentum, action-reaction force, angular kinematics, etc.
Biomechanics of Volleyball Float Serve
To ensure a successful volleyball serve, it is essential for the player to maintain proper positioning and body language because it helps in an appropriate transfer or circulation of momentum and generation of a high magnitude force. The muscles and joints of the player’s upper and lower limbs such as the feet, ankle, knee, hip, shoulder, wrist, and elbow play a major role in the volleyball serve. Initially, the player must align his/her feet in an ‘L’ or ‘V’ shape while maintaining an appropriate stance on the ground that is neither too wide nor too narrow. The majority portion of the server’s bodyweight must be properly concentrated on the back foot. This helps to improve stability or steadiness. The ball should be held firmly in the non-dominant hand. To initiate the service, the player pulls his/her dominant arm backwards while simultaneously flexing the elbow and maintaining a stable position of the wrist. The deltoid coracobrachialis and the clavicular head of the pectoralis major tend to act together and help to stretch the shoulder. The ball is then thrown up into the air and the server takes a step forward. This transfers the player’s body weight from the back foot to the front foot. The back foot, knee, and ankle bend while extending the hip. As the ball falls down, the player’s dominant shoulder, elbow, and arm extend while the wrist stays still. The player then hits the ball with the palm of the dominant hand and finishes the serve.
Phases of Volleyball Float Serve
There are basically five phases of a float serve, namely start position, ball toss, acceleration, ball contact, and follow-through.
The start position is the initial most stage of a volleyball serve. Here, the main focus of the player is to establish a comfortable position. The comfortable stance and positioning of feet vary from person to person. The player standing on the ground can have his/her stance shaped like the English alphabets “V” or “L”. To initiate the serve the player tends to rotate the left foot externally. The non-dominant hand is aligned at an angle equal to 90 degrees with respect to the ground, while the dominant hand is raised behind the head with the shoulder set at an angle equal to 90 degrees. An appropriate start position helps the player generate an adequate amount of acceleration and force required to serve the ball.
The ball toss is the phase of the volleyball serve where a push movement is provided to the ball. Here, the ball is tossed up in the air causing the joints such as the wrist joint, elbow joint, etc. to get extended. The toss must start from a low position to increase the magnitude of the applied force. This means that if the ball is tossed from a lower position, more force gets build up in it and if the ball is tossed from a comparatively higher position, the magnitude of the force that gets build up is comparatively low. When the ball is held in the player’s non-dominant hand, it does not have any momentum. The push force applied to the ball builds up velocity and generates momentum. The gravitational force of the earth acts as the reaction force and pulls the ball back to the ground. The ball toss should have an appropriate position. It must not be too low, too high, too front, too back, too left, or too right. The ball is hit when it reaches its highest point in the air.
This phase of the volleyball serve involves the movement of the player’s dominant hand in the backward direction. The hand is placed behind the player’s head close to the ear. If the player bends his/her elbow, the moment of inertia decreases significantly leading to a faster angular velocity. This helps the player to deliver a fast serve. If the player does not bend his/her elbow, the moment of inertia would be too large and would result in an unsuccessful float serve. During the process, the shoulder moves and the body rotates. The dominated arm is accelerated as fast as possible to produce an increased momentum. A high magnitude of velocity produces a high momentum that is prominent to achieve a successful serve. During the acceleration phase of the standing float serve, there exists torque at certain points of the player’s body including the torso, hips, and shoulders. Greater magnitude force applied to the ball during the service builds a greater magnitude torque. To accelerate the ball at a faster rate, the athlete hits the ball with his/her full hand. The palm must be in contact with the ball to generate a sufficient amount of force that is required to toss the ball over the net. The momentum transfer takes place from the athlete’s lower body to the upper body.
In this phase of the volleyball serve, the coefficient of restitution plays a major role. It is the ratio of the final to the initial relative velocity between two objects after they undergo collision. When the coefficient of restitution is sufficiently high, the ball quickly gets bounced off the player’s hand. The hand position must be steady to avoid the spinning of the ball. To increase the coefficient of restitution, the contact between the palm and the ball must be brief. This helps in an effective transfer of force from the athlete’s palm to the ball.
Follow-through is the final step of the volleyball serve. This is most important to avoid any sort of injury and to improve the athlete’s efficiency to deliver a good serve. The deceleration of the body takes place in this phase and the muscles tend to settle down to their original position with no velocity and a greater amount of inertia.