Dylan de Blaquiere
HLPE3531
Flinders University
South Australia
Indoor volleyball is a fast paced sport that involves many biomechanically rich movements. The Olympic audience loves the sport because of its tight scores, smash hits and perfect teamwork (Tang, 2013). The volleyball spike is an attacking movement that uses force generated from the body to give the projectile (the volleyball) a high velocity. Ball velocity along with accuracy, spin, a high point of contact and angle are key elements of an optimal volleyball spike.
HLPE3531
Flinders University
South Australia
Indoor volleyball is a fast paced sport that involves many biomechanically rich movements. The Olympic audience loves the sport because of its tight scores, smash hits and perfect teamwork (Tang, 2013). The volleyball spike is an attacking movement that uses force generated from the body to give the projectile (the volleyball) a high velocity. Ball velocity along with accuracy, spin, a high point of contact and angle are key elements of an optimal volleyball spike.
The primary movement
involved in a volleyball spike is an overarm movement. Overarm movement is an essential skill in a
range of different sport games such as tennis, baseball, water polo and
American football. Overarm techniques differ for throwing or hitting because of
rules, ball size, weight and strategies (Wagner et al. 2012). The most dangerous
offence in volleyball is a powerful spike, which is also one of the most
complicated skills in sports (Plawinski, 2008). The optimal technique is to hit
the ball with a high point of contact with the palm of your hand whilst
snapping the wrist to generate topspin.
Before continuing reading,
please click the link below to watch the volleyball spike in slow motion to
grasp an understanding of the correct technique.
Video 1:
Biomechanics represent the
science behind sports involving laws and principles to improve skills and
prevent injury. To categorise the movement, the spiking action is identified in
four key components; the approach, the take off, the arm swing and the hit/follow
through. Figure 1 identifies the complex biomechanical movements involved in a
volleyball spike.
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| Figure 1
Source: USA Volleyball (2015).
|
The Approach
The approach phase refers to
the step sequence of the athlete from the beginning of the run up to right
before take off. This stage is critical as it is the first stage of force
production to gain momentum for the jump. Momentum is the product of mass off
the player multiplied by the velocity of the approach (p= mv) (Blazevich,
2012).
The optimal run up for a
volleyball spike is three steps at four meters per second with a two-feet
take-off (Tang, 2013). Run up steps can vary with preference although three
steps is ideal. The jump should be side-on with the leading foot forward so the
body can have a large range of motion as it opens up for the swing. This
approach enables the spiker to gain horizontal momentum, which must be
converted into vertical momentum through subsequent flight (Forthomme et al.
2005). As the momentum of the body builds up kinetic energy it must transfer
into potential energy by keeping the body moving. If the body slows down it
will lose kinetic energy which will consequent in a smaller jump height
(Blazevich, 2012).
This is regarded as the
optimal approach to a volleyball swing although there is the one-step take off
that can also be used. The one step jump can generate a higher point of contact
and is used in some striking attacks such as quick plays. It is difficult to
maintain balance and timing using this approach, which is why the conventional
two-step method is ideal for the majority of spiking. Jumping off one foot also
makes it more difficult to control the landing without touching the net.
The final stage of the run
up is a squat, to prepare for the jump. At this stage the centre of mass
gradually lowers down to create a force acting on the ground, which equals to
the force acting on the body (Newtons 3rd Law)(Blazevich, 2012). The
momentum from the run up in conjunction with the vertical force from the push
of the legs toward the ground creates a summation of forces to propel the
player upward and forward.
As the ball is in flight the
brain subliminally interprets external factors to help with the timing of the
run up to optimally hit the ball with a late approach and a fast swing. The
brain uses the equation (Velocity = Distance/Time) to estimate the timing
needed for the approach (Blazevich, 2012).
Take Off
The vertical jump allows the
player to contact the ball overhead at the highest possible point of the jump.
This creates the opportunity to strike the volleyball down into the court on
the opposite side of the net (Briner & Kacmar, 1997). This is the crucial stage where the horizontal
momentum from the approach is converted into vertical momentum.
Depending on strength, flexibility
and coordination, effectiveness of volleyball spikes has been credited to energy
transfer in a kinetic chain concept from the lower limb to the upper extremity (Forthomme
et al. 2005). During this process as the athlete is jumping, the upper body is
moving upwards and the centre of mass is moving downwards which causes the
upper body to momentarily remain stationary and “hang” (Blazevich, 2012).
At the moment of take-off, the
action time is short so conservation of momentum is achieved. The following
equation can be derived from the Conservation Law of Momentum (Fd = mv)
(Forthomme et al. 2005). As the player jumps, Newtons 3rd law comes
into the equation as the action of forces are mutual and the force acting on
the ground is equal to the force acting on the human body (Tang, 2013).
Arm Swing
The arm swing phase occurs
when the player is in flight right before they make contact with the ball. This
stage is one of the most important stages because it prepares the body for the
hit using the force and momentum that has been generated.
This is a vital stage of the
skill, which comprises of three phases; back swing phase, turn swing phase and
the forward swing phase. The backswing is the initial phase that has a leading
back swing during take off and a pulling back action similar to an archer
pulling back an arrow. This is initiated by the pull of elbow and the wrist
simultaneously. During the turn-swing phase the trunk of the athlete turns
which allows for a greater range of motion as the arm naturally goes to the
upside down V position. The swing phase the elbow straightens until the ball is
hit by the upward extended hand, which is slightly in front of the shoulder for
optimal range of motion and forward momentum as the ball is struck (Lintner,
Noonan & Kibler, 2008). This description is shown in Figure 2.
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Figure 2
Source: Learn Volleyball Skills, (2015)
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The athlete transfers power
to the ball using Newton’s 3rd law of motion action and reaction force and the conservation of angular momentum
(Tang, 2013). As the athlete’s arms are moving downward (clockwise) through the
spike the legs move upward (anti-clockwise) which is noticeable because they
have a greater inertia (Blazevich, 2012). This is identified in Figure 1 toward
the end of the sequence and also in the videos that have been displayed. This
process occurs to maintain constant momentum. The Law of Conservation of
Momentum below indicates that momentum remains in the system unless external
forces such as gravity and air resistance act upon it.
The total angular momentum of a system remains
constant unless external forces influence the system.
(Blazevich, 2012).
Hit and Follow Through
To create a powerful spike
the athlete must transfer the force that has been generated in the body from
the approach and the arm swing. Ball velocity and accuracy are two key factors
in a successful spike. The moment of force (torque) is also important as it
influences the spin on the ball, which plays a big part in ball placement (Blazevich,
2012). Torque is identified by the following equation.
Torque = Inertia x Angular Acceleration
Momentum is equal to the
force applied on the ball multiplied by time the force is in which the force is
applied (Blazevich, 2012). This identifies that the shorter amount of time the
hand is in contact with the ball, the greater the force will be on the ball. The
athlete uses core muscles from the trunk and shoulder rotation to transfer
power into the hit, as seen in Video 1.
The Magnus Effect refers to
spin and air resistance that influence the direction that the ball can go.
Elite players must take this into consideration and hit the ball with a
snapping wrist action to generate topspin on the ball. This will ensure the
player can hit the ball with maximum force and the ball will dip down into the
court. There is a follow through action so there is no momentum lost during the
hit.
The follow through is an
equally important process to land correctly and prevent injury or a foul. A correct
follow through process is also crucial to prepare for the next spike, as it is
a very fast-paced game.
The Answer - How to Maximise These Effects and Perform
an Optimal Spike
There are a lot of factors
that influence the volleyball spike. Height and arm length are two major
biological factors that influence a successful spike. The higher the point of
contact is on the ball the more angular opportunity there is to hit the ball into
the court. Long levers (arms) create an advantage because they can achieve a
higher angular velocity, as there is a greater distance between the axis of
rotation and the point of contact.
The optimal technique has
been discussed in depth with biomechanical laws and principles to reinforce the
understanding. The approach of a three step, two foot jump is optimal to
generate maximum force. This approach with a high jump and a strong-arm swing
further generates momentum. The wrist must snap when making contact with the
ball to generate topspin so it can dip and land inside the court. This is also
essential to beat the oppositions defence block. With a lot of force and no
wrist snap the ball is likely to go out of court and be unsuccessful. A highly
skilled attacker spikes on average 40,000 times per year, so technique is critical
to maintain consistency and prevent injury (Forthomme, 2013).
Optimally, an athlete with a
low mass and strong lower legs will result in a higher jump. Newton’s laws
state that the lower the mass then the less force is needed to lift the body
from the ground. A tall athlete with long limbs, a low body mass in conjunction
with a high jump, good fitness and a good technique will be a highly efficient
volleyball attacker.
Here is a video of
professional athlete Denis Kaliberda spiking, to show you how effective a spike
can be.
Video 2
How else we can use his Information?
To achieve maximum velocity
and make the spike forceful, there are technical essentials for the lower limb
movement in the process of arm-swing based on the conservation law of momentum
(Tang, 2013). The waist, abdomen and lower limbs must generate force with the
upper limbs at the same time to form a radian so the upper limbs can generate a
greater force. These principals are also used in many other sports that involve
jumping and overarm movements. Vertical leaps are used in a range of sports
such as basketball, football and netball. Principals that relate to angular
velocity and torque are used in all sports that use levers and overarm
movements such as baseball, tennis, American football and badminton. The Magnus
effect can also relate to any sport that involves a ball such as golf and
tennis. The volleyball spike uses a combination of elements that directly
relate to numerous other sports and movements. It is a complex skill that
requires a disciplined technique in order to become successful.
References
Blazevich, A. (2012). Sports
biomechanics the basics – optimising human performance. London. A&C Black.
Briner
W., Kacmar L. (1997). Common injuries in volleyball: mechanisms of injury,
prevention and rehabilitation. The American journal of Sports Medicine, 24. 65–71.
Forthomme, B., Croiser, J.,
Ciccarone, G., Crielaard, J. & Coles, M. (2005). Factors correlated with
volleyball spike velocity. The American journal of sports medicine, 33(10),
1513-1519. DOI: 10.1177/0363546505274935
Learn Volleyball Skills,
(2015). Volleyball hitting techniques. Retrieved from http://learnvolleyballskills.com/.
Lintner,
D., Noonan, T.J., Kibler, W.B., (2008). Injury patterns and biomechanics
of the athlete’s shoulder. Clinical Sports Journal of Medicine, 27(4),
527-551.
Plawinski,
M.P., (2008). An Analysis of the Different Spike Attack Arm Swings Used in
Elite Levels of Men’s Volleyball. Kingston, Ontario, Canada: Queen’s
University.
Tang, D. (2013). A
study of key technical factors of volleyball spike based on the biomechanic analysis.
Information Technology Journal, 12(19), 5166 – 5171. DOI:
10.3923/itj.2013.5166.5171
USA Volleyball (2015). The
volleyball spike. Retrieved from http://www.teamusa.org/.
Wagner, H., Pfusterschmied,
J., Tilp, M., Landlinger, J., von Duvillard, S. P., Muller, E. (2012).
Upper-body kinetics in team handball throw, tennis serve and volleyball spike.
Journal of medicine and science in sports, 24(2), 345-354. DOI: 10.1111/j.1600-0838.2012.01503.x
Youtube Australia, (2015).
Epic volleyball spike: Denis Kaliberda. Retrieved from https://www.youtube.com/watch?v=z75KZqFTXeg.
Youtube Australia, (2015).
How to spike a volleyball in slow motion. Retrieved from: https://www.youtube.com/watch?v=FMtUqoxfR50
