Now that it has been established what the important
biomechanics are behind the volleyball dig moving on to the answer for
sub-questions can be done. So how does the dig become to have greater or less
accuracy? The angle which the ball is hit also discussed as the angle of incidence is important as if
this is too little or to great the ball will be propelled in an angle which is
not ideal. I took the liberty of getting shots of the ball being hit outside of
my predicted op5timum angle of the ball being hit in. As can be seen in image
3, when the volleyball is hit from approximately 80 degrees to the body, the
ball rebounds off the platform of the arms at a similar angle to which it
travels in prior to contact.
Image 3: A demonstration of when the ball is made contact with at or below 80 degrees to the body that it rebounds in the direction it travelled in the curvilinear path prior to contact.
The image below is when the ball is hit at an angle greater
than approximately 95 degrees to the body and can be seen in the next screen of
the action, the ball travels in a direction which is not ideal. The ball moving
backward means that the team mate of the person who performed the dig is not
able to achieve a set close to the net which is ideal in the volleyball rally (Crossingham,
2008).
Image 4: This sequence of images show that when the ball is hit greater
than approximately 95 degrees to the body the ball will travel a path which is
away from the anterior (front) of the body.
If an angle less than 80 degrees to the body and greater
than 95 degrees doesn’t provide the optimum angle to make contact with the
volleyball in the dig it means that between 80 and 95 degrees is ideal. This can
be viewed in image 1 from the first post of this blog where the player for
Floyd Central’s has lowered her centre of gravity to achieve the ideal angle of
incidence. This image is portrayed with image 5 below where an image of a 180
degree protractor was lined up with the straight of it to her back and shows
that the angle in which the ball was hit is that of 90 degrees.
Image
5: A modification of image 1 showing that the angle which the volleyball was
made connection with is the optimum angle of 90 degrees to the body. Reprinted from VOLLEYBALL: Floyd Central too tough
for Stars in, Hoosier Hills Conference Sports, September 2013. Retrieved 14 June,
2014, from: http://thehhcsports.com/volleyball-floyd-central-too-tough-for-stars-3/.
This
theory was a bit more difficult to show as for me to perform the use of leavers
to execute the shot through the use of swinging the arms, my technique had to
be modified. Due to this the kinetic chain technique of the push-like movement
pattern was looked into and captured first.
Push-like movement
pattern of the kinetic chain:
As
discussed in the biomechanical principles behind the volleyball dig, the body
is able to produce more force as the joints of the body are extending at the
same time (Blazevich, 2010). After 10
attempts in doing this style of dig, the ball went into the area which was
marked with a circle 8 of these times. This although is a small scale and with
only one subject to prove the point, shows that this technique is 80% accurate.
Image 6 below shows how this testing was set up.
Image
6: The set up for testing of accuracy using the push-like movement pattern.
Arms as levers for
technique of the volleyball dig:
This
technique used the same set up, the use of a circle of where the ball is wanted
to go to and the same amount of attempts using the shoulders as a pivotal point
for the levers of the arms to make contact with the volleyball in the dig. This
technique proved less accurate as only 50% of the shots (5 out of 10) went in the
circle. Although this may be the case for me personally performing the dig in
this style, someone who is more used to it and it comes naturally to them may
have more accuracy as diversity is a part of sport.
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