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The Volleyball Spike

The volleyball spike is perhaps one the most iconic movement in sports. When one performs the spike, it showcases the mastery of the balance between timing and skill. However the spike may also represent one of the most biomechanically complex movement. The spike comprises of 3 phases: the approach, the jump and the swing. The seamless transition between the three phases is essential for a score-winning spike. In the approach the player moves horizontally towards the net. Once the play has reached the optimum velocity and position, they transition to the jump phase, which transforms the forward momentum upwards to reach the highest point possible. As the player approach the top of the jump, when the ball is within reach, the player then enters the swing phase and contacts the ball. Of course this is a broad overview of the movement in whole. This article will focus on the latter 2 parts of the movement (the jump and the spike). After incorporating the approach (left-right-left step) the player will have decreased the distance between the player and the ball. Using these steps to generate the momentum needed to launch the player into the air and to spike/hit the ball.

Overview of the swing:

The swing phase in this article will be defined as the time between when the player is fully airborne and when the player contacts the ground. When the player is in the air they will bring their dominant arm back to their ear level and the elbow bent. The player should incorporate an arch in their back in order to generate more power in their hit (stretch shortening cycle). As the player approaches the highest point of the jump and the ball is within hitting distance the player will swing their arm, leading with the elbow, to the anterior aspect of the player’s body. The player will then proceed to “snap” (hip flexion, accelerating the arm anteriorly while extending the elbow and flexing the hand) and contact the ball. At this point the player should keep their hand spread open as it allows a greater surface area contact and more accurate hit. The player should strive to achieve topspin. The generation of topspin creates a velocity difference between the top and bottom of the ball and therefore an air pressure difference (Bernoulli's principle). The lower air pressure at the bottom of the ball modifies the trajectory and as a result it would move towards the ground at a steeper angle. This ultimately eliminates the horizontal translation of the ball that would cause it to become out of play. As the ball makes contact with the hand the player will also snap their wrist generating as well to push the ball down. After the contact is made the arm will follow through and bend in order to avoid contact with the net (which is a fault).

Figure 1 Bernoulli's principle. http://library.thinkquest.org/C005776F/Default.htm

Biomechanical Analysis of the Spike:

To analyze the spike in more detail we must consider the 3 phases of the swing briefly highlighted in the overview

The Arm cock: (Reference to the “Upper Limb Biomechanics during the volleyball spike”)

                  

The arm cock phase includes the movement of arms move towards a “cocked” position. That is, when the non-dominant arm is extended at the elbow and internally rotated at the shoulder (Reeser et al., 2010) and points at the ball, tracking it, while the dominant arm is flexed and brought up beside the head. The dominant arm achieves this by, “abducting and externally rotating the dominant upper body limb at the shoulder,”(Reeser et al., 2010). The non-dominant arm’s position relative to the body has a two effects. One of the purposes of the arm movement is to act as a counterweight to balance out the dominant arm when it is in the cocked position. The other functionality of the extended non-dominant arm is to act as a driving force in creating rotational momentum of the trunk in the arm swing, which will be discussed in the swing phase. In addition to the arm movement, the body concurrently arches back (back extension). The purpose of achieving the “cocked” position is to allow the body to create a stretch-shortening cycle across the dominant limb’s shoulder and body. At this position the player will be ready to rapidly and forcefully swing and contact the ball.

Figure 2 Cocked arm phase. This and that, Ripple’s page. http://ripley.za.net/2012/08/sport/olympics-phelps-makes-more-history

The Arm Swing

                 

It is essential for the player to time the initiation of the swing as they reach the maximal height of their jump. This provides an advantage that is, “the higher the spiking point, the higher the spiking height, the harder for the opponent to block the ball, and increased spiking ability,”(Hu et al., 2005). When the condition is right that is the maximal height has been reached and the ball is in position the play can initiate the swing phase. During the swing phase, “the attacker uncoils the upper limb (described as “cracking” the whip) to contact the volleyball at the desired overhead position,”(Reeser et al., 2010). The contraction of the muscles in dominant arm (allowing it to move from the cocked position to an extended position) in addition to the contractions of the abdomen (causing hip flexion) generates momentum that will be transferred to the ball as the player contacts it. The swinging motion of the arm which is synonymous to the, “effectiveness of tennis serves and baseball pitches has been attributed to and energy transfer in a kinetic chain concept from the lower limb to the upper extremity,”(Forthomme et al., 2005). However the difference is that the lower extremities (basically legs) are not directly involved in the execution of the volleyball spike. 

Figure 3 Top of Swing Phase. Volleyball 1on1. http://www.volleyball1on1.com/volleyball-spike/

Follow-Through and Landing:

                  

After the ball has been hit, the player is now in the last phase of the spike, the follow-through. The follow-through is perhaps the most overlooked part of the spike. As previously mentioned, during the approach, it is vital that the player positions themselves close enough to the net to allow the spike to travel downwards, yet far enough from the net to allow a proper follow-through. The follow-through in volleyball serves the same function as the follow-through in a golf swing or a tennis serve. A component that would increase the force transferred to the ball is accelerating through the hit. That is to accelerate the swing past the point of contact.

Figure 4 Follow-through phase. Strength and Performance training, Inc. http://saptstrength.com/2012/01/13/vertical-jump-initial-testing-is-it-really-the-bees-knees/volleyball-spike-2/

Directing the spike:

Following the swing phase, after the player hits the ball, the non-dominant arm will now be used as a driving force for trunk rotation. Trunk rotation functions mainly for directionality of the spike and has some secondary functions as a torque generator. The main purpose of the trunk rotation is to send the ball cross-court. It was observed that, “players were more rotated through their trunk toward the cross-court target,” (Mitchinson et al., 2013). After the trunk rotation the dominant limb will follow through and now be in a position that is in front of the body. After making the hit the player will follow through and proceed to land bending their knees to absorb the shock from the land. (Maybe you can put a bit more information here about landing and injuries?)

How to generate the max velocity of the ball during a spike?

The answer to this question depends on one key variable. That is, is the player hitting against an opponent? In this article, the execution of the hit is done at the highest possible point of the jump. The reason being, it makes it more difficult the defending player to block the hit. One of the most prevalent factors in achieving the maximum spike velocity is the activation of muscles from the most distal part of the spike (the abdomen). The summation of rotational angular momentum starting from the most distal body part will allow the greatest velocity to be achieved at the hand; this is synonymous to throwing a baseball. Another factor is at what position the contact of the ball happens. As with a baseball throw, a thrower would not throw with their arm at the highest point. The third and final factor would be to which direction the ball is hit. When a play hits a cross-court spike, due to the angle between the ball and the net, the ball would have to travel a larger horizontal distance before clearing the net. Such a hit is easier to perform but presents a few drawbacks. That is a player must provide a greater horizontal component of force to allow the ball to stay in play. The second type of hit is the line hit. In this type of spike the player aims along the sideline on which player is. The player then hits the ball straight down. Less emphasis on the horizontal component as well as an increased applied vertical force allows the player to hit a much faster spike compared to the cross-court hit.

Works Cited

Forthomme , B., Croisier, J.-L., Ciccarone , G., Crielaard, J.-M., & Cloes , M. (2005). Factors Correlated With Volleyball Spike Velocity . The American Journal of Sports Medicine , 33 (10), 1513-1519.

Hu, L.-H., Chen, Y.-H., & Huang, C. (2005). A 3D ANALYSIS OF THE VOllEYBAll SPIKE . 290-292.

Mitchinson, L., Campbell , A., Oldmeadow, D., Gibson, W., & Hopper, D. (2013). Comparison of Upper Arm Kinematics During a Volleyball Spike Between Players With and Without a History of Shoulder Injury. Journal of Applied Biomechanics , 155-164 .

Reeser, J., Fleisig, G., Bolt, B., & Ruan , M. (2010). Upper Limb Biomechanics During the Volleyball Serve and Spike. 368-374.

Wagner, H., Tilp, M., von Duvillard, S., & Mueller, E. (2009). Kinematic Analysis of Volleyball Spike Jump . Int J Sports Med , 760–765 .