PRIMARY QUESTION ANSWER

This is an example of the full technique of a volleyball spike from position four on the court. (AcuSpike, 2015)

Run up

Foot contact with the ground of leading leg prior to the jump

The foot to ground contact of the first step (if the hitter is right handed this should be the right foot) in the run up phase of the skill should consist of contact to the ground beginning with the heel then following through to the toes. This motion of foot contact utilises the momentum of the hitter's body in order for the following leg to reach an even stand point before taking the jump, reducing likelihood of the hitter hopping instead of jumping. By utilising the body's own accumulating momentum, the power of the successive jump is increased. The contact of the heel to the ground first creates force in a downwards motion that will in return be propelled back up through the body from the ground in order to create a stronger and more powerful jump. Newton's Third Law states that every action has an equal and opposite reaction, this is the return of force into the jump from the contact of the foot to the ground prior to the jumping phase. Contacting the foot on the ground heel to toe allows the foot to be in contact with the ground for a longer time. This then allows for more speed to be gained during the run up which then transfers into more momentum in the jump. This aspect of the run up is also affected by the speed of the run up. Novice hitters have the tendency to slow their run ups reducing the force that is translated through the foot contact into the jump. For a successful spike to be executed a hitter must contact the ground with their leading leg heel first and at their top speed in relation to their run up. When angular momentum of the leg is maximised during the run-up phase, this will hopefully translate into a higher jump. Angular momentum is a function of moment of inertia and angular velocity (Magias, 2015).

Arm swing during run up

Arms start in a neutral position. With the first step the arms move slightly forward out in front of the body. With the next step the arms swing back behind the body as high as is comfortable for the hitter. They stay in this position until the hitter begins to jump. The movement of the arms slightly forward should be done softly to avoid an opposite reaction driving the body backward. However, the arms should still be moved forward to allow a large swing backwards. This swing action backwards creates more momentum for the body to move and lean forward. The arms remain up and back behind the body ready for the jumping phase.

Jump

Foot contact with the ground at the beginning of the jump

Back foot (right foot if right hand hit) contacts ground heel toe, front, foot lands only on the ball of the foot. By the time the front foot reaches the ground the back foot will also be on the ball of the foot ready for the jump. By the whole of the back foot being placed on the ground this allows it to make contact for longer. This translates into more force downwards for a higher jump up (Newton’s Third Law). Here angular momentum should also be maximised for the hitter to jump higher; angular momentum is greater when joint torque is produced over a longer period of time (Magias, 2015). So again the foot to ground contact time being longer allows for a higher jump. The front foot should land on the ball of the foot as this means the body position has to be leaning slightly more forward. This will aid in a higher vertical jump and will be further explained in the ‘body position prior to jump’ phase.

Body position prior to jump

The main reasons why this position is employed are to maintain balance, and jump higher. The feet are slightly apart to create a stable base of support and they’re at an angle to the net to encourage the same angle from the body. The body is now open to more hitting options without the risk of injury. The torso leans forward to create a lower centre of gravity for better balance and to allow the arms to swing back further. With the arms starting up further more momentum can be gained from the swing (as the swing is longer, therefore takes more time) and transferred into upwards momentum for the jump.

Motion of the arms throughout the jump

The arm swing begins with relatively straight, stretched out arms behind the body. The arms swing in a circular motion down then forward and up, still out stretched until they are above the head and parallel with the body. Starting with the arms as far back behind the body is important to create more time in the swing. This way the arms are able to accelerate more with more time which will aid in creating more vertical momentum in an upward direction and also more force; this will lead firstly to a higher jump and secondly the force can then be transferred into a harder hit. The arms move with angular momentum as they have angular velocity. The arms rotating up want to continue rotating up; creating momentum for the body in an upwards direction. By having the arms outstretched instead of close to the body they also create more torque which in conjunction with time creates a greater angular impulse; contacting the ball with a large impulse creates greater velocity therefore enabling a more successful spike.

Body position at peak of jump

The body position at the peak of the jump consists of an arched back, open shoulder, shoulders rotated to face court, legs have already been stretched back out and non-hitting arm has started to push down. The back is arched and the shoulders open to create maximum angular velocity. Opening the body up allows more time for the body to create more force and velocity. This then translates into a harder, faster hit.

This image displays the arched back at the peak of the jump. (lovedecor, 2015)

Downward movement of non-hitting arm

Pushing the arm down during the jump is done for a few reasons. The first relates to Newton’s Third Law. The arm pushes down with force to push the body up. The other is to rotate the body and transfer the downward momentum into the hitting arm for a faster hit.

Extension of legs downwards at peak of jump (to increase hang)

The legs are straightened again while in the air of the jump, this occurs for two reasons. The first can be explained with Newton’s Third Law. The legs extend down with force which pushes the body up, this then conserves vertical momentum in an upward direction gained from the jump (Magias, 2015). Secondly, extending the legs shifts the hitter’s centre of mass. The centre of mass is moving down due to the influence of gravity. Once the legs extend the upper body is essentially moving upwards. This shifts the centre of mass back up allowing the hitter to ‘hang’ in the air.

This video demonstrates the biomechanics of an optimal vertical jump that is needed to have a successful volleyball spike. Best examples come after 3:07. (bsizzle, 2014) 

Hitting Phase

Body position/rotation when arms are in ‘V’ cocked

The body position during this phase consists of opened body across the shoulders, facing the rest of the court. Both arms are up. The shoulder of the hitting arm is further away from the net than the non-hitting arm and cocked back in a ‘V’ position. The reason for this position is to allow the hitter more time and space to accelerate their arm so the ball can be hit with more force. Beginning with a body position open to most of the court also allows the player to hit with more variability without injury. The non-hitting arm moves back down before the hitting arm starts to swing. Newton’s Third Law applies to this action as bringing the arm down works in two ways; the first being body rotation. Once the front arm moves down the back shoulder is essentially forced forward to begin the swing of the hitting arm. The second force it creates is by moving the arm down it pushes the body up, this allows the body to ‘hang’ in the air longer. The movement produced from the cocked back ‘V’ position through to contact with the ball is a throw-like movement pattern as “a volleyball spike is performed with a sequential movement pattern where the proximal joints increase their velocity first and the more distal segments increase their velocity later" (Blazevich, 2010). Throw-like movement patterns attain higher velocity as they gain momentum through the production of large muscles and in this instance the body.

This image demonstrates the cocked 'v' position that the arm takes before hitting. (lovedecor, 2015)

Follow through

A follow through is important after a hit to ensure maximum force has been placed behind the ball. Following through with arm swing ensures that a maximum possible time has been spent contacting the ball (Physics of Volleyball, 2015). This enables the hitter more time to accelerate and therefore hit the ball with more force. This force and acceleration is also transferred into the ball after an effective hit. Following through will also help the hitter maintain balance upon landing as the centre of gravity has shifted back down. 

This image sequence is an example of a correct technique of a volleyball spike. (Learn Volleyball Skills, 2015)

This video displays an array of volleyball spike plays by professional athletes however, number 2 (3:32) and 15 (1:00) display the best technique demonstrations. (Epic Volleyball, 2014)