Volleyball Float Serve: A Biomechanical Analysis 1 Jesse Barfknecht Nicole Cereda Volleyball Float Serve: A Biomechanical Analysis In 1895, William G. Morgan invented the game of volleyball. Since then, volleyball has become a mainstream sport and has many different variations. Today, volleyball is played recreationally and competitively by people of all ages and both sexes. This paper looks at certain aspects of volleyball; how it is played, specific skills, differences between male and female players, results of playing, and more. Looking at the game of volleyball, it does not appear to be a game that requires precision, timing or any complex movement skills. Most novice players or beginners will just focus on trying to not let the ball hit the ground or try and hit the ball over within the limit of three hits. To really achieve a high level of play, discipline and practice of high difficult degrees of movements need to be done. Volleyball has many movements other than just striking the ball with extremities. Players must be able to get in the right position both vertically and horizontally. Lateral movements that precede an attack can give players the maximum chance in achieving the best outcome. Environments like beach volleyball cause different challenges with sand slowing the acceleration of movements. Perez-Turpin et al. (2009), break down the chart of movement patterns using camera and video analysis tools and software. The data showed that the players used offensive movement patterns fifty nine percent of the time and defensive patterns forty one percent of the time.
27
Embed
Volleyball Float Serve: A Biomechanical Analysis 1getoffyourbutt.weebly.com/uploads/1/4/3/2/14327358/...Volleyball Float Serve: A Biomechanical Analysis 3 reception digs, shot spikes,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Volleyball Float Serve: A Biomechanical Analysis 1
Jesse Barfknecht
Nicole Cereda
Volleyball Float Serve: A Biomechanical Analysis
In 1895, William G. Morgan invented the game of volleyball. Since then, volleyball
has become a mainstream sport and has many different variations. Today, volleyball is played
recreationally and competitively by people of all ages and both sexes. This paper looks at certain
aspects of volleyball; how it is played, specific skills, differences between male and female
players, results of playing, and more. Looking at the game of volleyball, it does not appear to
be a game that requires precision, timing or any complex movement skills. Most novice players
or beginners will just focus on trying to not let the ball hit the ground or try and hit the ball over
within the limit of three hits. To really achieve a high level of play, discipline and practice of
high difficult degrees of movements need to be done.
Volleyball has many movements other than just striking the ball with extremities. Players must
be able to get in the right position both vertically and horizontally. Lateral movements that
precede an attack can give players the maximum chance in achieving the best outcome.
Environments like beach volleyball cause different challenges with sand slowing the acceleration
of movements. Perez-Turpin et al. (2009), break down the chart of movement patterns using
camera and video analysis tools and software. The data showed that the players used offensive
movement patterns fifty nine percent of the time and defensive patterns forty one percent of the
time.
Volleyball Float Serve: A Biomechanical Analysis 2
While the game is still played the same with the same rules, there are some change
attributes of the net when males and females play. To play the game with the net the same height
for women as men would be unfair as males are on average taller than the ladies counterparts.
The net is lowered to adjust for the high differential between the two sexes. Other possible
differences in physical characteristics and attributes between males and females were researched
for an article about sex differences. The research analyzed sex differences in statistics. The focus
was on shot spikes, reception digs, and fault serves. The researchers used the software, VIS from
the International Volleyball Federation. In order for them to be able to identify which variables
were discriminated by sex, they computed a discriminate analysis which led to their adoption of
a .30 coefficient structure. (Joao, Leite, Mesquita, 2010)
From the study, the researchers concluded that “men’s volleyball performance was
more strongly associated with terminal effects (errors of service), whereas women’s volleyball
performance was characterized by actions of continuity (effective defense and attack).” (Joao,
Leite, Mesquita, 2010, p. 897-8) The authors also concluded that there are differences in men’s
and women’s statistics due to their body build. They stated that different “strategies and tactical
procedures, and training should be focused on tasks that integrate perceptual decisions, and
motor components.” (Joao, Leite, Mesquita, 2010, p. 898)
After analyzing the results, the differences between men’s and women’s spike, fault
serve, shot spikes, fault blocks, and rebound blocks, appeared to be significant with the men
scoring higher. The women scored higher in the reception digs, still sets, digs, and fault sets.
There was no significant differences for the reception serve aces, serve hits, fault spikes, kill
blocks, and serve receptions. A discriminate function was present only when it pertained to
Volleyball Float Serve: A Biomechanical Analysis 3
Volleyball Float Serve: A Biomechanical Analysis 15
Volleyball Float Serve: A Biomechanical Analysis 16
Discussion:
The subject side stepped laterally across the width of a standard volleyball court which is
30ft wide. Each segment was broken down into a distance of 7.5 feet. Based on the results the
subject accelerated past the first to marks then let up through the 3rd segment then sped back up
for finish.
Comparing the acceleration of the subject shows that he started off very well but decided
to slow down during the 3rd segment. The graph above shows the deceleration during that
segment and how once the subject was almost to the end he picked up the speed to finish strong.
To better performance for the test subject changes to a few areas need to be addressed.
The first change should be to encourage the subject to go at full speed for the whole test. A
distance of 30 feet should not be a problem for a person to maintain full speed throughout the
test. Second, the subject’s arms could be placed in a better position. The subject had his arms
right at his side and if they were wider out if could increase his balance at a higher speed as a
lack of balance may have been why he decelerated during the test.
The last study that was done was on the kinematics of the float serve in volleyball. The
researchers looked at different aspects of the body and ball relationship.
Introduction:
The purpose of this study was to examine the ball movement and release angles during
the float serve. The study focused specifically on the release angle of the ball in order for the ball
to hit a horizontal target effectively. The study also focused on ball movement, acceleration, and
velocity of two subject’s float serves.
Volleyball Float Serve: A Biomechanical Analysis 17
Methods:
For the analysis, two recreational volleyball player’s float serve were compared. Both of the
recreational volleyball players were observed in real time. Both players preformed the float serve
in a gym while being videotaped. The video was filmed with a Samsung Galaxy S2 a resolution
of 1920x1080 at 30fps. Frame count analysis was performed using Apple QuickTime software.
The results were found by using the Kinovea software.
Results:
Figure 1
Volleyball Float Serve: A Biomechanical Analysis 18
Figure 2
Figure 3
Table 1 Subject 1: Ball Acceleration and Velocity
29.41 35.71 38.46 38.46
Volleyball Float Serve: A Biomechanical Analysis 19
Avg. Velocity (ft/s)
Avg. Acceleration (ft/s^2)
40.66 20.35 0.00
(∆v/∆t)
Volleyball Float Serve: A Biomechanical Analysis 20
Table 2 Subject 2: Ball Acceleration and Velocity
Avg. Velocity (ft/s)
38.46 50.00 50.00 41.67
(∆d/∆t) Overall 44.44444
Avg. Acceleration (ft/s^2)
100.33 0.00 -75.76
(∆v/∆t)
Volleyball Float Serve: A Biomechanical Analysis 21
Conclusion:
When aiming to hit a horizontal target, the most effective release angle for the object is an angle
equal to or greater than 45 degrees. In figure 1, Subject 1’s release angle of the ball during a float
serve was analyzed. Subject 1’s release angle was 53 degrees. In figure 2, Subject 2’s release
angle of the ball during a float serve was analyzed. Subject 2’s release angle was 46 degrees.
Volleyball Float Serve: A Biomechanical Analysis 22
When comparing the two subjects’ release angles, Subject 2’s release angle is more effective
when it is applied to a float serve. Subject 2’s release angle was seven degrees less than Subject
1’s. With having a lower release angle, Subject 2’s ball crossed the top of the volleyball net
closer than Subject 2’s ball. This is beneficial for the serve, so that it is able to drop inside the
court boundaries. The higher the release angle, the more chances there are for the ball to land
past the end line of the court.
The study shows the velocity and acceleration of the 2 subjects serving a volleyball using
a technique to create afloat serve. The distance being measured is 30ft. 30ft represents the
distance from the subject to the middle of the court where the volleyball net stands. Note the
differences between Subject 1 and Subject 2. Subject 1's serve had a lower maximum velocity as
well as it did not hit its peak speed until the later end of the serve where as Subject 2's serve hit
its maximum velocity right away. The differences between velocities could be the force at which
the ball was contacted as well as the trajectory of the ball during the serve.
With the float serve the less rotation on the ball is better so it creates a high amount of
drag and the ball creates an unpredictable path during its flight. Figure 3 represents the flight
pattern of the ball during a serve. As you track the ball from the toss, from the start the ball
is drifting slightly horizontally to the right. When the ball comes down and contact is made,
the trajectory of the ball is continued to the right. The longer the ball is in flight the more
drag builds up and can create the sporadic flight pattern. Looking closely at the line you can
see a big shift to the right as well as curves that sway horizontally as the ball descends. The
movement of the ball horizontally represents a proper float serve was executed.
Volleyball Float Serve: A Biomechanical Analysis 23
To conclude the research, the authors looked at five biomechanical principles and applied
them to the volleyball float serve.
Physics of Volleyball — The Magnus Effect and Air Resistance
The airborne time of the volleyball can be reduced even more by putting top-spin on the
volleyball. This causes the ball to experience an aerodynamic force known as the magnus effect,
which "pushes" the ball downward so that it lands faster. The figure below illustrates the magnus
effect.
For a proper float serve, the person should limit any type of rotation on the ball or the
magnus effect will take over and eliminate the odd unpredictable movements of the float serve.
If the ball is served with any form of topspin it causes the velocity of the air around the top half
of the ball to become less than the air velocity around the bottom half of the ball. This is because
the tangential velocity of the ball in the top half acts in the opposite direction to the airflow, and
the tangential velocity of the ball in the bottom half acts in the same direction as the airflow.
This causes a net downward force to act on the ball. This is due to Bernoulli's principle which
Volleyball Float Serve: A Biomechanical Analysis 24
states that when air velocity decreases, air pressure increases (and vice-versa).
Surface Drag
The motion of a float serve is created by aerodynamic drag. The magnitude of the drag
depends on the viscosity of the air. Along the solid surface of the ball a layer of energy flow is
generated. The magnitude of the friction depends on the state of this flow. The drag and forces
exerted against it in flight create an erratic flight path of the volleyball during a float serve.
Impulse and Inertia
Impulse = force x change in time. In a serve, the impulse experienced by an object
= the change in momentum of the object. During the float serve, this is when first contact is
made during the serve. Inertia is essentially an objects resistance to acceleration. When a
volleyball player strikes the ball during the float serve its inertia keeps it moving with speed.
Without inertia the ball would fall straight to the ground after contact. The principle of inertia
as described by Newton in his First Law of Motion; that an object not subject to any net external
force moves at a constant velocity. Thus an object will continue moving at its current velocity
until some force causes its speed or direction to change such as striking the ball during the float
serve.
Changes in uniform motion
The starting velocity of a volleyball float serve is zero. The player is stationary and the ball is
held out in front of the player with no movement. The ball then has a small degree of velocity
dropping down in preparation for the toss. The velocity increases during the toss to get the ball at
the proper level for striking while the serving arm eccentrically contracts at a low degree of
Volleyball Float Serve: A Biomechanical Analysis 25
velocity. The force of the impact comes from the mass of the striking arm’s concentric
contraction during the action phase.
The ball’s velocity instantly changes from a slow speed, vertical velocity to a high speed,
horizontal velocity. After the striking arm contacts the ball, there is a slowing down velocity of
the arm until it comes to a stop. The degree of velocity change is high, due to the need of a
minimal follow through of the float serve. The kinetic energy of the arm is transferred into the
horizontal movement of the ball.
Factors influencing stability
While performing a volleyball float serve, the base of support comes from the feet being
shoulder width apart, with one foot slightly in front of the other foot. With this staggered form,
there is more anterior and posterior support and less side to side movement support. The center
of gravity within the body is lower during the preparatory phase, the toss of the ball, and higher
during the action phase, the hitting of the ball.
The action and ending phases are the only times that directional stability is observed. When
those phases are being performed the player is slightly moving forward in anticipation of making
contact with the ball and completing the serve. With the forward directional stability, there is
weight transfer. During the preparatory phase, the weight is evenly distributed between both feet.
Once the action phase starts, weight is transferred to the hitting hand side foot. At the end of the
action phase when the ball is contacted, the weight transfers to the non hitting hand side foot.
Volleyball Float Serve: A Biomechanical Analysis 26
When the weight transfer is taking place and the ball is being contacted with the hand,
directional instability is observed. The body is not completely stable during movement and does
not have a solid base with weight evenly distributed on both feet.
References:
Alfonso, J., Mesquita, I., Marcelino, R., & da Silva, J. (2010). Analysis of the setter’s tactical action in high-performance women’s volleyball. Kinesiology, 42(1), 82-89.
Bergün, M., Mensure, A., Tuncay, Ç., Aydin, Ö., & Çigdem, B. (2009). 3D kinematic analysis of over arm movements for different sports. Kinesiology, 41(1), 105-111
Ciapponi, T. M., McLaughlin, E. J., & Hudson, J. L. (1996). The volleyball approach: An exploration of balance. Proceedings of the XIIIth International Symposium on Biomechanics in Sports, 282-285.
Coleman, S. (2005). A 3D kinematic analysis of the volleyball jump serve . Coaches Info. Retrieved January 15, 2012, from http://www.coachesinfo.com/index.php?option=com_content&view=article&id=375%3A3dkinematic-article&catid=103%3Avolleyball-generalarticles&Itemid=197#conclusion
Volleyball Float Serve: A Biomechanical Analysis 27
Cortell-Tormo, J., Pérez-Turpin, J., Chinchilla, J., Cejuela, R., & Suárez, C. (2011). Analysis of movement patterns by elite male players of beach volleyball. Perceptual And Motor Skills, 112(1), 21-8.
Escamilla, R. F., & Andrews, J. R. (2009). Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports Medicine, 39(7), 569-590
João, P., Leite, N., & Mesquita, I.J. (2010). Sex differences in discriminative power of volleyball game-related statistics. Perceptual And Motor Skills, 111(3), 893-900.
Lajtai , G., Pfirrmann, C., Aitzetmüller, G., Pirkl, C., Gerber, C., & Jost, B. (2009). The shoulders of professional beach volleyball players: high prevalence of infraspinatus muscle atrophy. The American Journal Of Sports Medicine, 37(7), 1375-83.
Pérez-Turpin, J. A., Cortell-Tormo, J. M., Suárez-Llorca, C., Chinchilla-Mira, J. J., & Cejuela-Anta, R. (2009). Gross movement patterns in elited female beach volleyball. Kinesiology, 41(2), 212-219.
In volleyball, crafty players serve up an aerodynamic crisis. (2004). Science, 306(5693), 42.