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As with the execution of any skill
there are various techniques which allow for successful execution of a free
throw, however most coaches and athletes prescribe to a similar set of
guidelines and skill cues which optimizes the chance for the result to be successful.
As such a basic guide can be described as, setting feet shoulder width apart
at the foul line, with both feet facing forward, right foot slightly in front
of left if a right handed shooter, with right big toe in line with the split
line of the court right the way to the center of the basket with the knees
having a slight bend. This position is effective in a number of ways, having
everything in a line from the basket to split line to toe, up the body to
elbow and finally to the ball can help eliminate movement off the line which
would cause the ball to miss left or right of the ring. By keeping the ball
in line there is a greater margin for error short or long of the ring on the
shot. This may vary as some players would prefer to line the middle of the
body up with the split line, however focusing on a common technique taught is
keeping everything in line. Commonly players then begin a routine which
may involve taking various bounces of the ball at the line. These help in a
routine where players are able to eliminate any other distractions and focus
on something they have performed thousands of times. At completion of the
routine, the ball is moved on to the fingers of the shooting hand where the
ball is just away from resting on the palm. Often in this stage a player will
align their middle finger with the valve or grooves on the ball to continue
the theme of keeping everything in line. The opposite hand is also involved
as a support for the ball, commonly this stage is referred to as a having an L
shape in the arm, in this position a player should be able to just see the
basket under the ball, this may vary depending on the individual. From this
position the shot is executed, power is generated from the legs before the
elbow is locked and the wrist is snapped still in the direction of the
basket. A follow through is the final aspect where a player will “hold” their
position until the ball travels through the ring, this allows for feedback as
to where the shot went right or where it needs to be improved/worked on. The
following YouTube clip gives a good fundamental explanation of how a free
throw is performed. http://www.youtube.com/watch?v=JYJquICUJCg
The Answer:
Newton’s Laws
Newton’s 1st Law
states 'An object will
remain at rest or continue to move with constant velocity as long as the net
force equals zero' (Blazevich, 2010, p.44). As such in regards to the free
throw an athlete must shift from rest to a vertical motion.
Newton’s
2nd Law ‘the acceleration of an
object is proportional to the net force acting on it and inversely
proportional to the mass of the object F=M x A’ (Blazevich, 2010, p. 45)
Therefore force must be applied by the athlete in order to accelerate the
ball to the ring.
Newton’s 3rd Law ‘for every action, there is
an equal and opposite reaction’ (Blazevich, 2010, p. 45), the free throw
requires vertical or downward force which is applied by the foot making
contact with the ground. The ground produces an equal and opposite reaction
force, this can accelerate the athlete forward or vertically if the force is
great enough to overcome inertia. This is demonstrated in figure 2.
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Figure 2:
demonstrating how downward force is applied creating an equal and opposite
reaction to push vertically. Source:
Blazevich, 2010, p.45
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The Law of
Gravitation: ‘All bodies are attracted to each other with a force
proportional to the product of the two masses and inversely proportional to
the square of the distance between them’ (Blazevich, 2010, p. 46).
Due
to the vertical nature of the free throw movement the impact of the
gravitational force means that a much larger force is required to
accelerate vertically upwards. All three of Newton’s Laws and the Law of
Gravitation work together to allow the athlete to come up onto their toes
or jump slightly to shoot the Free Throw. To be able to do this inertia
needs to be overcome, this happens by having an applied force against the
earth, through equal and opposite reaction the result is the shooter coming
up onto their toes or in a controlled jump in their shooting motion.
Projectile
Motion
A
projection can move at any angle between 0 degrees (horizontal) or 90
degrees (vertical). Trajectory is influenced by the projection speed, the
projection angle and the relative height of projection (Blazevich, 2010, p.
25).
Projection
speed: projection speed determines the distance covered by a projectile,
the higher speed projectile is travelling the further it will go. Regarding
the free throw the basketball travels vertically, therefore the projection
speed will determine the height is reaches before gravity accelerates it
back to earth.
Projectile
angle: refers to the angle the projectile is launched and effects the range
of a projectile, an object projected between 0 degrees and 90 degrees will
travel vertically and horizontally.
Relative
height of projection: the vertical distance between the projection point of
an object and the point in which it lands.
Research shows
that the optimum angle to shoot a free throw is approximately 51 degrees
(Gordon, 1997, p. 495). To have the greatest chance of shooting a
successful free throw this angle is suggested due to the ball having the
maximum area to go through the ring when the projectile is launched at
this angle. A different angle will result in the ball having a smaller
area to go through the ring, resulting in the ball to hit the ring and
rebound or skim in different directions. To be able to determine the optimum
flight path for each individual biomechanical analysis and tests would
need to account for different physiological features which may vary the
release point, these may include height and length of player’s arms.
The Magnus Effect
The effect of spin on a basketball shot is quite profound
and can as Hubbard states result in a more successful result if correctly
executed, as more backspin on the basketball for a shot which falls short
or travels too far is more likely to allow the bounce up and drop into
the basket (Hubbard, 206, pp. 1303-1308). Alexander (1990) found that
when appropriate backspin is placed on the ball the horizontal velocity
of the ball decreases if it strikes the ring, as well as causing the ball
to rebound downwards of the backboard, thus allowing for a higher margin
for error in the shot. The effect of backspin can be generated quite
simply by having an emphasis on the basketball resting on the fingers
through the motion and snapping the wrist and flicking the fingers. The
following video gives a solid understanding to how the Magnus effect
influences an objects flight through the air.
Force Summation
Where the basketball is given momentum generated by each
part of the body, this is maximized when the bigger muscles are used to
fuel smaller muscles, as such power is generated from the larger
muscles in the legs opposed to just the arms. As such correct timing,
through to the great range of motion will gain maximum momentum
(Brancazio, 1981, p. 358). This begins with the legs pushing into the
ground, travel through the hips up to the shoulders and arms to the
tips of the fingers where the ball is released.
The free throw can be described as a push like movement
pattern where all joints are simultaneously extended, this is
demonstrated when the knees and elbow are extended at the same moment.
A push like movement is as it sounds a movement where we move as if we
are pushing something. This action produces a higher overall force due
to the growing forces generated by each joint acting together
(Blazevich, 2010, p. 196). These movement patterns are very efficient
and can produce highly accurate results due to the nature of the
simultaneous rotations in a straight line at the end of the kinetic
chain.
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Work, Energy and Power
The relationship between work power and energy can be
used to improve the performance of the free throw; these elements are
present through the motion when the player bends up from their knees
up onto their toes, pushing the ball up towards the basket. This
relationship can be described as ‘The amount of work done is equal to
the average force that is applied multiplied by the distance of which
it is applied. W= F x D’ (Blazevich, 2010, p. 100). This
is a product of force and displacement, force provided over a range
of object movement. Power is the ‘rate of doing work, work per unit
time or the product of force and velocity’ (Blazevich, 2010, pp.
101-102).
How
else can this information be used?
Naturally the free throw in basketball and other
sports where a similar shooting action is present contain comparable
biomechanical principles. The netball shot is one such action, where
a player will align feet, generates momentum from bending their knees
and push up from the ground onto toes. However there is a difference
in the follow through of the two shots where in a free throw the
elbow is locked and wrist is snapped of the shooting hand compared to
the netball shot where both hands are used in the follow through.
Adding to this is the fact that a free throw is executed without any
active defensive pressure, where the netball shot is often executed
with at least one defender active in between the shooter and the
ring. Similarly the set shot in basketball commonly referred to as a
“catch and shoot” requires similar principles to the free throw. The
major difference being the use of the legs to create greater force in
order for the ball to travel a greater distance to the basket, the
aspect of active defenders is also another aspect regarding the set
shot.
There are numerous aspects of any sport which similar
biomechanical aspects are applied, examples in the sport of
basketball can include the use of newton’s laws in particular
newton’s second law as well as, vertical impulse, work, power and the
kinetic chain. An example of this could be the aspect and skill of
rebounding where the maximum jump height and energy required can be
utilized. The movement of maximal jumping also relates to skills in
other sports such as, the volleyball spike or block where repeat
efforts of maximal jumping may be required. Various aspects are
present in multiple sporting situations, for example the Magnus
effect is present in numerous sports, including soccer, cricket, baseball
and golf
This information can lead to successful teaching of
the basketball free throw, accurate analysis of players’ individual
techniques will be better informed by coaches, teacher, parents and
fellow players.
Reference List
Alexander, M. (1990). The application of biomechanics
to basketball skills. CAHPER
Journal, 56(3), 4-10.
Blazevich, A. (2010). Sports Biomechanics The Basics:
Optimising Human Performance. London: A&C Black Publishers.
Bradley, S., & Martin, J. R. BIOMECHANICAL ANALYSIS
OF BASKETBALL FREE THROW SHOOTING.
Brancazio, P. J. (1981). Physics of basketball.
American Journal of Physics, 49, 356-365.
Gordon R, Hamilton & Christoph, Reinschmidt.
(1997). Optimal Trajectory for the basketball free throw. Journal
of Sports Sciences, 15(5),
491-504.
Hubbard, H & Okubo, M. (2006). Dynamics of the
basketball shot with application to the free throw. Journal
of sports science, 24(12), 1303.
Hudson, J. L. (1982). A biomechanical analysis by
skill level of free throw shooting in basketball. Biomechanics
in sports, 95-102.
Kozar, B., Vaughn, R. E., Whitfield, K. E., Lord, R.
H., & Dye, B. (1994). Importance of free-throws at various stages
of basketball games. Perceptual
and Motor Skills, 78(1), 243-248.
Satti, S. (2004). The perfect basketball shot. Int
J Nonlinear Mech, 6, 22-9.
Spina, M. S., Cleary, T. D., & Hudson, J. L.
(1996). An exploration of balance and skill in the jump shot.
In Proceedings of the XIIIth
International Symposium on Biomechanics in Sports (pp.
294-297).
Tran, C. M., & Silverberg, L. M. (2008). Optimal
release conditions for the free throw in men's basketball. Journal
of sports sciences, 26(11),
1147-1155.
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