Information‐movement
coupling is a fundamental concept, integral to theorist on the coordination of
goal‐directed activity in ecological psychology. Throughout this blog, we
examine the implications of biochemical principles, research and the notion of
newtons laws, during the acquisition of movement coordination in sport tasks.
The task vehicle for our analysis is interception actions, in particular
self‐paced extrinsic timing tasks exemplified by Spiking in sports such as
volleyball. Recent research highlighting the relevance of information‐movement
coupling for the process of practice in sport is discussed. We conclude that
information‐movement coupling represents an important principle for the
structural organization of research and practice in self‐paced extrinsic timing
tasks and that further work is required to verify its significance across a
range of sport movements, (Davids, 2008).
When the volleyball spike is broken down into movement
phases, the specific bodily movements can be analysed through a bio mechanical
approach. This approach will assist in improving the performance of the
individual through quantitative research. Quantitative analysis can be
explained through many bio mechanical principles to provide specific numerical
information about the movement analysed (Wuest & Fisette, 2012, p.206).
Specific information regarding aspects such as the joint angles during
movement, the force generated, and the speed of movement is provided. The
analysis of the volleyball spike will follow a quantitative approach that will
ideally improve an individual’s execution of the skill.
Newtons laws in the Vertical Jump
There are several principles that are relevant in analysing
the preparation phase of the volleyball spike in order to maximize the power
and speed. The volleyball spike should initially begin when the set is half the
distance to the spiker. There are several footwork patterns that a volleyball
player may use in order to execute the volleyball spiker, but it can be seen
that not all are as efficient bio-mechanically when compared to the muscle
expenditure of certain jumping techniques (Ziv & Lidor, 2010, p.562).
When the spiker jumps, they are applying a vertical and
horizontal force when the feet contact the ground (Blazevich, 2012, p.45).
Newton’s Third Law explains the action and reaction of the spikgoogleers jump from
the ground
During Newton’s Third Law a vertical force is applied when
the foot makes contact with the ground. The ground then exerts an equal and
opposite reaction force (Blazevich, 2012, p.45). The volleyball spiker must be
conscious of the fact that if the force is large enough to overcome their
inertia during the ground contact the equal and opposite reaction will
accelerate them forwards (Blazevich, 2012, p.45). This movement is beneficial
but it must be timed accurately so that the spiker does not make contact with
the net, it can also be important that combining elements as well as the
players coordination to execute accurately.
The Law of Conservation of Momentum states that the momentum
of a system remains unchanged unless it is acted upon by an external force
(Blazevich, 2012, p.112). This knowledge can be used to analyse a volleyball
players body mass in proportion to their momentum which can ultimately increase
their jump velocity. For example a 60 kg volleyball player can produce enough
force to gain a momentum of 840 kg∙m∙sˉ¹. However if they lost 3 kg in body
mass their jump velocity would increase by 0.7 m∙sˉ¹ (Blazevich, 2012, p.217).
Contact
High shoulder forces and torque are generated in the
volleyball spike (Escamilla & Andrews, 2009, p.580). Torque refers to the
movement of force being the magnitude of force which causes the rotation of an
object (Blazevich, 2012, p.63). To maximise the volleyball spike it is
essential to create a longer lever. By doing this a greater distance between
the axis of rotation (shoulder) and the point of contact (hand) is created
which will allow for a higher rate of velocity (Blazevich, 2012, p.20). The
longer the arm, the higher the chance for increasing the distance between the
muscle and the joint which, therefore, results in the arm being able to apply
greater amounts of torque on the ball.
For example the picture shows a greater
distance between the axis of rotation (shoulder) and the point of contact
(hand) is created which will allow for a higher rate of velocity.
In the volleyball spike it is important to recognise that
the aim of spiking the ball is to transfer the maximum amount of momentum from
the body and into the ball. The volleyball player is required to transfer the
kinetic energy produced into potential energy. Therefore, it can be explained
that the shorter amount of time that the hand is on the ball, the greater the
force that is able to be maintained and applied to the ball (Tiffany, 2002).
The Magnus effect refers to changing of trajectory of an
object towards the direction of spin which result from the Magnus force
(lifting force acting on a spinning object) (Blazevich, 2012, p.240). In order
for a volleyball to move in a near-random trajectory along a near-parabolic
path it is more accurate to hit the ball with no spin at all (Blazevich, 2012,
p.221). However, in the volleyball spike it would be more effective to place
topspin on the ball to maximize power, speed and accuracy.
Magnus effect showing that the change in
trajectory, giving the spiker the ability to create topspin.
According to the Magnus effect, if topspin (where the top of
the ball spins over the bottom of the ball) is placed on the ball, the air on
top of the ball would slow down and the air underneath the ball would move
reasonably faster (Blazevich, 2012, p.193). This results in a Magnus force
where the pressure on the top of the ball would be higher which would cause the
force to be directed down towards the ground resulting in the ball dipping
(Blazevich, 2012, p.619). Understanding the ability to relay this knowledge is
another example of how effective the principles of the Magnus Effect are when
teaching hitters that they can apply maximum force without compromising
accuracy.
Finish and Recover
The follow through phase is equally as important as the
preparation and contact phase. The aim of the follow through is to make a clean
recovery so that no foul can be called or no injury can occur while in
transition to the next play. It is crucial for
volleyball player to keep their head and eyes still during the execution
of the spike (Blazevich, 2012, p.66). This will ultimately improve the accuracy
of the movement while the center of mass rises and falls during the jump of the
spike (Blazevich, 2012, p.66). The landing of the spike requires the
dissipation of the kinetic energy that is generated during the athletes jump
(Tillman, Hass, Brunt, & Bennett, 2004, p.31). The increase in the jump
height must be followed by a relative increase in the kinetic energy which is
required to be absorbed by the body in order to avoid injury and gives the
player the best chance to return to the starting position ready for the next rally.
The Answer
Looking to the overarching question of this blog ‘what are
the bio-mechanical movement principles that are crucial to the volleyball spike?’
It is clear that there are a number of factors that influence an individual’s
ability to successfully perform the skill. Starting with Newton’s Laws of
Motion and how an athlete can maximize their vertical jump height, through
firstly overcoming inertia, then applying force, which is then applied back
through them courtesy of the ground. It is crucial to have low body mass and
have the ability to produce large vertical forces to jump high. In addition to
Newton’s Laws of Motion, another two bio-mechanical principles that are
important in applying maximum force during the volleyball spike are angular
velocity an moment of force (torque). These principles are closely linked to
height and as such arm length, which results in a greater capacity to apply
force to the ball. Genetics also play a
key role in determining how much force one can exert on the ball during the
volleyball spike. Lastly, when looking more at accuracy, topspin and the
principles of The Magnus Effect give athletes the knowledge that if they can
correctly apply topspin to the ball it will greatly enhance their ability to
hit the ball with force as well as accuracy. Finally, these bio-mechanical
principles are just some of the many examples of factors that are crucial in
applying power and achieving greater accuracy during the volleyball spike and
it is the combination of these as well as regular training that will see the
greatest improvements. To finish the spike efficiently the landing requires the
dissipation of the kinetic energy that is generated during the athletes jump
(Tillman, Hass, Brunt, & Bennett, 2004, p.31). These factors combined will
ultimately assist a volleyball player in producing a spike that is both
powerful and fast while maintaining accuracy.
How else can we use this information?
The information gathered for the purpose of this blog is not
exclusive to volleyball and can be applied to many different sports. To begin
with, the principals involved with increasing vertical leaping ability can be
closely linked to numerous other sports where athletes are required to jump repeatedly.
For example, basketball players, ruck-men in the AFL and even wide receivers in
the NFL all need to focus on reducing body mass and increasing the amount of
vertical force they can produce. Furthermore, the principles of Angular
Velocity and Moment of force (torque) can be also be transferred to a number of
other sports namely baseball, cricket and tennis (in fact any sport using a
racket or bat). The greater the distance between the axis of rotation and the
force (to a optimum point of course) would result in an increase in force
application on an object. Moreover, these principles can even be utilized by
runners, whereby longer limb length allows for a faster linear foot speed and
thus faster movement. Finally, when looking at the Magnus Effect, there are
implications for any sport that uses a ball. When looking at the volleyball
example where topspin can be the primary examples are tennis and cricket where
applying spin on the ball can significantly improve performance.
An
example
transfer of information from this blog into other sports can be shown in this
simple design of an over arm throw and comparing to a volleyball spike.
References
Blazevich, A. (2010). Sports biomechanics, the basics:
Optimising human performance. A&C Black
Davids, K., Button, C., & Bennett, S.
(2008). Dynamics of skill acquisition: A constraints-led approach.
Champaign, IL: Human Kinetics.
Davids, K, Kingsburya,
D, Bennetta, S, & Handford C,
2001, Information-movement coupling: Implications for the organization of
research and practice during acquisition of self-paced extrinsic timing skills
Journal of Sports Sciences, Volume 19, Issue 2 viewed 22 May 2015.cb
Fitness Testing: Vertical Jump Testing, viewed 20 May,
2015 http://www.topendsports.com/testing/results/vertical-jump.htm
Tillman, M. D., Hass, C. J., Brunt, D., & Bennett, 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.
