Biomechanical Analysis for the optimal technique of the
Volleyball Spike
Introduction
Biomechanics is the
study of the body in a mechanical sense. This field attempts to make sense of
the complexity of human movement by looking at the parts involved. The
biomechanics of volleyball refers to the application of this field specifically
to the movements in the sport.
The actions
of volleyball are a complex combination of strength, power, agility, and
finesse. Each of these components is comprised of complex, small movements, the
summations of which are synchronized acts of striking the volleyball in
a desired fashion. The volleyball spike is a perfect example of this and, when
executed correctly, is one of the most exciting shots in the game. It involves a powerful downward ‘spike’ motion
over a net with the aim of being unreturnable by the opposition.
Due to the many
aspects related to the biomechanics of volleyball, not every strike of the ball
is perfect. Many times, mistakes made by athletes are due to the
impossibility of executing hundreds of tiny movements perfectly every single
time. Learning how to spike correctly is essential to becoming an
effective offensive volleyball player, one way of improving an athletes spiking
technique is through a biomechanical analysis of the skill. In this instance we
will be specifically looking at, and breaking down, the key movement phases involved
with a successful volleyball spike and examining the key biomechanical
principles necessary for an effective shot.
Figure 1 – Spiking Technique (Image: https://www.pinterest.com/pin/105271710012814223/)
Pre Jump (Preparation)
The approach or preparation phase of the volleyball spike,
is the means by which an attacker gains speed on the ground prior to jumping.
That speed is translated into approach jump height. That is a horizontal force
is transferred into a vertical force. Thus, the approach is a critical
component of a successful offense in volleyball. Ideally, the hitter will use
the approach to achieve a high jump with minimal horizontal motion. (Mann, 2008) For the analyses of
the preparation phase it will be important to consider Newtons Laws of Motion.
Newton’s First
Law states that “An object will remain at rest or continue to move with
constant velocity as long as the net force equals zero” (Blazevich, 2012). The
pre-jump preparation phase contains a running approach that is key in order to
give the athlete maximum momentum for the height of the vertical jump in the
takeoff phase (Kessel,
2013). The components of
momentum are the velocity of approach and the mass of the player, which in turn
relates to the optimal momentum that can be gained for maximum velocity of the
vertical height in the jump.
The athlete
applies a force larger than the present inertia, resulting in an increased
running speed on approach to the jump. This leads to Newton’s Second Law which
states “The acceleration of an object is proportional to the net force acting
on it and inversely proportional to the mass of the object” (Blazevich, 2012).
It is advised to plant and take off quickly during an
approach. This is due to the concepts of kinetic energy and potential energy.
During the approach the body has kinetic energy, or otherwise can be described
as energy in motion. The goal is to transfer this into potential energy. If it
comes to a stop the kinetic energy is less, therefore, you can't jump as high (Blazevich,
2012).
The importance of the jump is emphasised in the next phase.
Jump
The volleyball spike requires athletes to vertically jump as high
as they are capable of. In order for the player to jump higher the greatest
vertical acceleration is required before leaving the ground to be able to
create the greatest initial vertical velocity (Ziv
& Lidor, 2010). The greater the velocity, the higher the centre of
mass will be able to be reached. The body needs to overcome inertia, by having
a force applied to the player and by applying a force against the ground that
provides an equal and opposite force back (Blazevich, 2012). The power of the
jump comes from the vertical force generated from the foot plant and push-off
of the legs using the major leg muscles. The transfer of momentum is due to the
direction of the foot plant and the use of the arm swing which gives assistance
to the height and direction of the vertical jump prior to take-off (Harrison
& Gaffney, 2001).
Jump height is important
to provide the hitter enough time in the air to choose the best shot, position
and to achieve the best angle on the ball (Lees, 2004). Leonel Marshall is a
Cuban volleyball player whose vertical leap was once measured at 50 inches.
This ability gives Marshall a tremendous advantage when spiking the ball, as
shown in the video below. (Also note his technique)
The improved range of motion for the arm swing along with
the prior time of initiation allows the arm to generate more energy, which is
transferred to various body points to improve vertical jump performance (Hsieh &
Heise, 1997).
The volleyball player would swing both arms back to the waist and then swing
the arms forward and upward in an effort to generate power for the spike. This
will accelerate the proximal segments of the arm. By accelerating the proximal parts
of the arm and then stopping them, there is transference of momentum along the
arm that consequently results in a high velocity of the end point (hand)
(Blazevich, 2012).
The throw-like outline in the volleyball spike can also be clarified
as it can be presumed that it makes the best use of the tissues that have the
fastest shortening speeds (tendons). When tendons are released they recoil at
high speeds indicating kinetic energy. However, the force in the tendon must be
high enough for the tendon to begin to recoil at very high speed (Blazevich,
2012). This explains that the inertia of the athletes hand must be overcome
first.
Contact
In the contact or ‘hit’ phase, the ball should be struck
while reaching up high with the arm straight, elbow extended, reaching directly
overhead or marginally in front of the body. The contact point of the ball and
hand should be at the peak of the jump to gain the most power and accuracy for
the shot (Lithio, 2006), by using a wrist snapping type motion to direct the
ball downward into the opponents court.
Notable shoulder forces and
torque are produced in the volleyball spike (Escamilla
& Andrews, 2009). Torque refers to the movement of force being the
magnitude of force which causes the rotation of an object (Blazevich, 2012). To
maximise the power and accuracy of the volleyball spike it is vital to form a
longer lever. By doing this a larger distance between the axis of rotation
(shoulder) and the point of contact (hand) is created which will permit for a greater
rate of velocity (Blazevich, 2012). The longer the arm, the greater the chance
for increasing the distance between the muscle and the joint which, consequently,
results in the arm being able to apply greater amounts of torque on the ball. Newton’s
3rd law of motion “action and reaction force” and the conservation of angular
momentum are used by the athlete to transfer power to the ball (Blazevich,
2012).
It is essential for the volleyball athlete to transfer the
kinetic energy produced into potential energy during the spike. From the
momentum-impulse theorem, momentum is equal to the force exerted on the ball
multiplied by the time in which the force is exerted (Blazevich,
2012).
Therefore, the shorter amount of time your hand is in contact with the ball the
greater the force is that is applied to the ball (Tiffany, 2002). This
again leads back to this quick snapping type motion when contacting the ball.
The Magnus effect and air resistance
The flight time of
the volleyball can be lessened by applying top-spin on the volleyball during
the spike shot. Top-spin causes the ball to undertake an aerodynamic force
known as the Magnus Effect. This
principle allows players to hit the ball with extreme force without hitting it
out or losing control. This is achieved through snapping the wrist downward
thus creating the top-spin; the ball will travel at a high speed before dipping
downward and landing in court. The figure below illustrates the Magnus Effect.
Figure 2 - The Magnus
effect. F = Force, V = Velocity. (Image: http://schemaroot.org/science/physics/effects/magnus/magnus_effect.png)
As the ball rotates,
friction between the ball and air causes the air to react to the direction of
spin of the ball. As the ball undertakes top-spin, it causes the velocity of
the air around the upper half of the ball to become less than the air velocity
around the lower half of the ball (Linnell, Wu, Baudin, & Gervais, 2007).
This takes place due to the lateral velocity of the ball. The upper half turns
in the opposite way to the airflow, and the ball in the lower half turns in the
identical direction as the airflow. This causes a net downward force (F) to act
on the ball. This also relates to Newtons Third Law by which the air exerts an
equal and opposite reaction on the ball which in this case is upwards. Multiple
varied flight paths can be made with volleyballs due to the exterior of the
ball being irregular and a varying surface roughness from the panels during the
flight (Blazevich, 2012). This force is useful for reducing the balls flight
time and thus decreases the reaction time for the opposing team.
This video explains the effects the Magnus effect can have on the ball:
https://youtu.be/23f1jvGUWJs?t=1m44s
Follow through
The last sequence
of the spike is the
follow-through phase which is equally important as the previous phases. The aims
in this phase are to stay technically clean, make a good recovery, as no foul
and no injury should happen in transition to the next play. Both the arm swing
after ball contact and the landing are components that, if botched, can contradict
the effects of all the previous phases discussed. The landing after the spike needs to dissipate the
kinetic energy that is produced during the athletes jump. The increase in the
jump height must be trailed by a relative increase in the kinetic energy which
is required to be absorbed by the body in order to avoid injury (Tillman, Hass, Brunt, & Bennett, 2004).
Conclusion
Based upon this discussion, it can be clarified through
biomechanical principles that there are several key aspects that support a
powerful, fast and accurate volleyball spike. The spike can be broken down into
the pre jump phase, jump phase, arm swing phase, the contact phase and the
follow through phase in order to analyse the important biomechanical principles
that affect each sequence and rely on the order to be chronological.
The above information can be utilised to increase spike
accuracy, and also to learn how to get more power and force into the shot.
Having a comprehensive understanding of these biomechanical principles not only
allows for improved comprehension of how to improve results within a volleyball
game context but, the principles can be transferred to other sports involving
jumping, arm swinging motions and projection of a ball.
Works Cited
Blazevich, A. J.
(2012). Sports Biomechanics: The basics: Optimising human performance (2nd
ed.). London: Bloomsburry Publishing.
Escamilla, R. F.,
& Andrews, J. R. (2009). Shoulder muscle recruitment patterns and related
biomechanics during upper extremity sports. Sports Medicine, 39(7),
569-90.
Harrison, A. J.,
& Gaffney, S. (2001). Motor development and gender effects on
stretch-shortening cycle performance. Journal of Science and Medicine in
Sport. 4(4), 406-415.
Hsieh, C., &
Heise, G. D. (2006). Important kinematic factors for male volleyball players
in the performance of a spike jump. Proceeding of American Society of
Biomechanics, 50-62.
Kessel, J. (2013).
How Can I Spike Harder? Retrieved from USA Volleyball:
http://www.teamusa.org/USA-Volleyball/Grassroots/SportKit/Player-Resources/How-can-I-spike-harder
Lees, A. (2004).
Jumping Heights. Journal of Biomechanics, 37, 22-30.
Linnel, W., Wu,
T., Baudin, P., & Gervais, P. (2007). Analysis of the volleyball spike
using working model 2D. Journal of Biomechanics, 40(2), 45-58.
Lithio, D. (2006).
Optimising a Volleyball Serve. Western Reserve University: Hope
College.
Mann, M. (2008). The
Biomechanics of the Volleyball Spike / Attack. Retrieved from Sports
Biomechanics:
http://www.sportsbiomech.com/Books/Biomechanics%20of%20volleyball%20spikes.pdf
Tiffany, T.
(2002). Physics of Volleyball. Retrieved from East-Buc:
http://www.east-buc.k12.ia.us/02_03/ce/tt/tt.html
Tillman, M. D.,
Hass, C. J., Brunt, D., & Bennet, G. R. (2004). Jumping and landing
techniques in elite women’s volleyball. Journal of sports science &
medicine, 3(1), 30-36.
Ziv, G., &
Lidor, R. (2010). Vertical jump in female and male volleyball players: a
review of observational and experimental studies. Scandinavian journal of
medicine & science in sports, 20(4), 556-567.
