Introduction
The different forces that act on the human body and the
effect these forces have on the human body is the underpinning of the science
of biomechanics. Biomechanics allows
educators, coaches and athletes to analyse the individual components of a skill
and have the scientific background to be able to do so (Snigh, 2013). Biomechanically, the volleyball overhead serve
can be applied to the concept of the kinetic chain, a series of linked body
parts that move together. More
specifically throw like movement patterns, meaning the kinetic chain extends
sequentially. (Blazevich, 2010, p196-198).
Major Question
The serve in volleyball is an integral skill within the modern game (Kumar et.al, 2012). The game is initiated with a serve and is described as the first offensive attack, in this case the overhead serve is the focus (Huang & Hu, 2007; Kumar et al., 2012). The overhead serve can either be performed as a float (video 1) or topspin (video 2) serve and can be accomplished from either a standing or jumping position. For a successful float serve the ball is hit with the heel of the hand, which produces no spin resulting in a path that is unpredictable (Nathial, 2012). While the hand placement of the topspin serve, the palm and fingers make contact with the ball provides the topspin, generating more power and is generally used in conjunction with a jump serve (Charalabos et al., 2013). Jump serves have a higher ball toss than a standing serve. When contact is made with the ball by the server off the jump, a strong downward motion from the striking arm makes it difficult for the defence to respond. Hence why it is favoured in Collegiate and Professional competitions (Charalabos et al., 2013; Nathial, 2012). During an overhead serve, whether it is float or topspin there are several characteristics that are common to both, the ball toss, arm swing, hand contact on the ball, foot placement and follow through (Nathial, 2012).
This information helped to form the question, what are the biomechanics behind performing a successful overhead volleyball serve?
This information helped to form the question, what are the biomechanics behind performing a successful overhead volleyball serve?
Video 1:The technique for the standing float serve (YouTube, 2014)
Video 2: The technique for the jump topspin serve (YouTube, 2009)
The Answer
Lower body movement
during standing float serve and jump topspin serve
The movement of the lower extremities is the beginning of
both the float and topspin serve. During
the float serve, the server steps forward with the non-dominant foot, making
contact with the ground where vertical force is applied creating an equal and
opposite ground reaction force (Newton’s Third Law). The force created as a result of foot contact
with the ground applies a force great enough to change the state of motion of
an object (Newton’s Second Law). During
the float serve it is the state of motion of the volleyball we are attempting
to change, from the current vertical force to a horizontal force. The force applied has to be large enough to
over the inertia of the ball (Blazevich, 2010, p.45).
The topspin serve comprises a run and jump component to it
serve. The run up consists of three to
four initial steps then a jump. To
achieve the optimum biomechanics during the short run up, each time a foot make
contact with the ground, it generates an equal and opposite ground reaction
force (Newton’s Third Law). There needs
to be the largest conceivable force applied for as long as possible, creating
impulse to generate the greatest change in momentum (impulse-momentum
relationship). The larger the force
generated the greater the transfer is during the jump stage of the serve. When transitioning from the run into the jump
there are both vertical and horizontal forces to be overcome in order to change
the state of motion. The ground reaction
force helps to propel the run forward and the jump up. The force applied from the ground reaction
force during the final step must be greater than the inertia created by the
server in order to initiate the jump (Blazevich, 2010, p.45-58).
Torso movement
through the float and topspin serve
During both the float and topspin, torso movement remains
the same, although the force generated by ground force reaction in the step
forward or run up is increased (Balzevich, 2010, p.45). The torso starts facing the net and the
rotation occurs at the transverse plane and rotates to a 45° angle,
which would not alter the current centre of gravity or centre of mass
(Blazevich, 2010, p.16). As the torso
rotates forward again, force is generated from the mass of the body and acceleration,
propelling the whole body forward. This
results in the hand of the service arm making contact with the ball. The rotation acts as another mechanism that
creates a force capable of changing a state of motion of an object (body being
propelled forward), as the force is great enough to overcome the inertia (Blazevich,
2010, p.8)
Upper limb mechanics
of the float and topspin serve
There are five phases when performing the float (figure 1)
and topspin serves (figure 2). At the
wind up phase of the arm movement during the float serve, the service shoulder
abducts while the non-service shoulders begins to extend, which starts the
release of the ball. The service arm
also exhibits flexion at the elbow decreasing the angle creating a smaller lever,
meaning the moment of inertia is also smaller (Blazevich, 2010, p.73; Rokito,
1998). The cocking phase initiates the
external shoulder rotation (torque) increasing the angle through extension at
the elbow, therefore increasing the moment of inertia. As the external shoulder rotation increases
and reaches its maximum it triggers the internal rotation of the shoulder and
extension at the elbow. When the torque
of both is at its maximum it initiates the acceleration to propel the arm
forward so the hand can make contact with the ball. During the acceleration transition into
deceleration the moment of inertia is greatest for the service arm. The service arm is completely straight producing
the longest possible lever increasing the force, accelerating the arm forward,
thus increasing the moment of inertia.
The deceleration and follow through see the service arm start to abduct
and continue to do so until it comes to rest at the service player’s side ready
to play the next shot (Rokito, 1998)
Figure 1: The motion for the standing float serve (Tribesports, 2012).
The only difference between the arm action of the standing
float and jump topspin serve is the arm action during the wind up phase. There is abduction of both the service and
non-service arm behind the body and by propelling the arms back towards the
body and then up above the head there is an increase in force generated from
the rotation (torque) (Blazevich, 2010, pp.63-65, Rokito, 1998). This combined with force generated from the
run up and torso movement increases the force that is imparted on to ball at
the point of contact, influencing the coefficient of restitution (Balzevich,
2010, p.73).
Figure 2: The motion for the jump topspin serve (Mercerisl and volleyballclub, 2015).
Impact of the hand on
the ball
When contact is made on the ball by the heel of the hand
during a float serve and the palm and finger during the topspin serve (figure 3), the
outcome is affected by both the coefficient of restitution and Magnus effect. The coefficient of restitution describes how
an object retains energy after a collision, in this case how much energy the ball
retains after colliding with the hand to be propelled forward (Blazevich, 2010,
p.117).
Figure 3: The different hand placement of the float and topspin serve (Volleyball, 2015).
Magnus effect demonstrates how the flight path of a spinning
object is affected by force (Blazevich, 2010, p.188). According to the Magnus effect during the
float serve, the unpredictable flight path is caused by the variation in rough
surfaces on the ball. Hitting the ball without
spin causes air flow to impact the path of the ball, it impacts the rough
surfaces causing the ball to rotate slightly.
As this is a continual effect throughout the flight path the ball
continues to rotate slightly, resulting in the unpredictable flight path
(Blazevich, 2010, p.192).
The flight path of the topspin serve is more predictable
than the float serve, however it is more difficult to return due to the heavy
topspin and speed at which it is hit (Kumar et al., 2012). When topspin is placed on a serve it is hit
with high horizontal velocity and the air flow around the top of the ball moves
at a slower pace than the airflow underneath the ball (relatively
quickly). The pressure exerted onto the
top of the ball causing a downward force is similar to that of the spike,
making difficult to return (Blazevich, 2010, p.193).
Injury concerns
The most common injury arising in volleyball related to the
serve is in the shoulder and occurs more often with the jump topspin serve than
with the float serve. Injuries to the
shoulder relate to chronic overload which is derived from a combination of repetitive
jump serves in association with spikes.
Volleyball players responsible for the spikes should limit the number of
jump serves they perform, specifically in practice (Resser et al., 2010). The float serve is safer in terms of
resultant injury compared to the topspin serve, however the topspin is favoured
at the collegiate and professional level due to the speed and ultimate placement
of the ball (Resser et al., 2010; Kumar et al., 2012).
How are the biomechanical
principles influenced by movement?
The kinematical variables assessed during the volleyball
serve are the joints where rotation occurs.
The joints assessed were the ankles, knees, hips, shoulders, elbows and
wrists, these are the angular kinematics.
The studies considered how each of the joints were affected at stance
and execution and whether there was any correlation between the two. Studies found that there was not a
significant correlation between stance and execution, concluding that angular
kinematics have a limited effect on the overhead serve (Nathial, 2012; Singh,
2013).
Blazevich, A. J. (2010). Sports biomechanics: the basics: optimising human performance. A&C Black.
Charalabos, I., Savvas, L., Sophia, P., & Theodoros, I. (2013). Biomechanical differences between jump topspin serve and jump float serve of elite Greek female volleyball players. Medicina Sportiva, 9(2), 2083-2086.
Escamilla, R.F., & Andrews, J. R. (2009). Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports medicine, 39(7), 569-590.
Huang, C., & Hu, L. H. (2007, December). Kinematic analysis of volleyball jump topspin and float serve. In 25 International Symposium on Biomechanics in Sports (pp. 333-336).
Kumar, A. (2012). Relationship of selected biomechanical variable with performance of volleyball players in jump serve. Sports and Yogic Sciences,1(3), 27.
Mercerislandvolleyballclub.com,.
(2015). CONDITIONING | Mercer Island Volleyball Club. Retrieved 19 June
2015, from http://mercerislandvolleyballclub.com/conditioning/
Nathial, M. S. (2012). Motion Assessment of Volleyball Overhead Serve. International Scientific Journal of Sport Sciences, 1(2), 105-112
Singh, M. SKILL ANALYSIS OF VOLLEYBALL SERVE THROUGH KINEMATIC APPLICATIONS.
Tribesports,. (2012). Float Serve. Retrieved 19 June 2015, from
http://community.tribesports.com/challenges/float-serve
REFERENCES
Blazevich, A. J. (2010). Sports biomechanics: the basics: optimising human performance. A&C Black.
Charalabos, I., Savvas, L., Sophia, P., & Theodoros, I. (2013). Biomechanical differences between jump topspin serve and jump float serve of elite Greek female volleyball players. Medicina Sportiva, 9(2), 2083-2086.
Escamilla, R.F., & Andrews, J. R. (2009). Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports medicine, 39(7), 569-590.
Huang, C., & Hu, L. H. (2007, December). Kinematic analysis of volleyball jump topspin and float serve. In 25 International Symposium on Biomechanics in Sports (pp. 333-336).
Kumar, A. (2012). Relationship of selected biomechanical variable with performance of volleyball players in jump serve. Sports and Yogic Sciences,1(3), 27.
Nathial, M. S. (2012). Motion Assessment of Volleyball Overhead Serve. International Scientific Journal of Sport Sciences, 1(2), 105-112
Reeser, J. C., Fleisig, G. S., Bolt B., & Ruan, M. (2010). Upper limb biomechanics during the volleyball serve and spike. Sports Health: A Multidisciplinary Approach, 2(5), 368-374.
Rokito, A. S., Jobe, F. W., Pink, M. M., Perry, J., & Brault, J. (1998). Electromyographic analysis of shoulder function during the volleyball serve and spike. Journal of Shoulder and Elbow Surgery, 7(3), 256-263.
Rokito, A. S., Jobe, F. W., Pink, M. M., Perry, J., & Brault, J. (1998). Electromyographic analysis of shoulder function during the volleyball serve and spike. Journal of Shoulder and Elbow Surgery, 7(3), 256-263.
Singh, M. SKILL ANALYSIS OF VOLLEYBALL SERVE THROUGH KINEMATIC APPLICATIONS.
Tribesports,. (2012). Float Serve. Retrieved 19 June 2015, from
http://community.tribesports.com/challenges/float-serve
Volleyball, H. (2015). How to Jump
Serve a Volleyball. wikiHow. Retrieved 19 June 2015, from
http://www.wikihow.com/Jump-Serve-a-Volleyball
YouTube. (2009). Jump Topspin Serve. Retrieved 19 June 2015, from https://www.youtube.com/watch?v=0XTB8vkV5bI
YouTube. (2009). Jump Topspin Serve. Retrieved 19 June 2015, from https://www.youtube.com/watch?v=0XTB8vkV5bI
YouTube. (2012). How to do an overhead volleyball serve. Retrieved 19 June 2015, from https://www.youtube.com/watch?v=9QRnGaFitCc