Thursday 19 June 2014

What is the ultimate technique for shooting a basketball foul shot?


Ray Allen is one of the best foul shooters with a career average of 89.39%
Introduction

The foul shot is one of the most important shots to make in basketball. All basketball players must be efficient from the foul line because it can be a determining factor in the result of the game. Repetition of practicing foul shots, a set routine at the foul line and sound technique help in a high success rate of foul shot makes. The basic technique for a foul shot is as follows:

·         Have the same foot as your shooting hand slightly forward of the other foot.

·         Bend at the knees and as the ball is almost released, rock upwards onto the toes.

·         Support ball with the hand of your non-shooting arm.

·         Keep forearm vertical before shooting.

·         Shoulder, elbow, and wrist should be in line with the rim before shooting.

·         During shooting, ball should move from below the chin towards an upward and forward direction.

·         Extend elbow fully at the ball release.

·         Follow-through by snapping wrist forward, so that the shooting hand is facing downward.

·         Release ball with your fingertips.

·         Hold follow-through (keep wrist firm) until the ball reaches the rim (Lam, Maxwell & Masters, 2009).

 

How to create power in a foul shot?

Newton’s laws of motion explains force production in a variety of sporting movements, including the basketball foul shot. Newton’s first law states that “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). An object that stays in its present state is called inertia and all objects that have a mass have inertia including a basketball (Blazevich, 2010). The larger the mass, the more inertia there is. Having a higher amount of inertia makes it difficult to create velocity of an object, stop an object and for the object to change direction (Blazevich, 2010). The foul shooter needs to create force, and can do so by using Newton’s third law, ground reaction force. “For every action, there is an equal and opposite reaction (Blazevich, 2010, p 45). Ground reaction force is present during the foul shot. When the foul shooter foot contacts the ground, the ground uses an equal and opposite reaction force (Blazevich, 2010). This allows the shooter to create enough force to overcome the inertia and propel the ball towards the ring. Newton’s second law allows the shooter to get power in the shot. “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). A foul shooter must apply force to create motion of the ball.

 
The kinetic chain (the moving chain of body parts) used in the foul shot is the push-like movement pattern. The push-like movement represents the impression that the person is pushing something.  A push-like movement is when all joints are extended all at once in a single movement (Blazevich, 2010, p 196). This results in everything acting together and the combined forces created in each joint causes a high overall force. Push-like movements are efficient because the joint rotations are simultaneous, causing a straight line movement at the end point of chain resulting in accurate results (Blazevich, 2010, p 197). In regards to the foul shot, the person attempting the foul shot extends their knee and elbow at the same time and this creates the force necessary to push the basketball in a straight line movement.

 
Notice how Steve Nash gets a lot of power from his knees and extends upwards vertically. Steve Nash is the most successful foul shooter in NBA history making 90.43% of his total foul shots.


The sum of forces is the momentum given to the object by each body part and occurs sequentially. To generate maximum momentum using each segment of the body from the large muscles in the legs into the small muscles last to generate force.  Correct timing, through to the great range of motion will gain maximum momentum (Brancazio, 1981). To attain power and efficiency in the foul shot the whole body is used. The shot begins with the movement of the legs, pushing into the ground. The force then travels from the legs into the shoulders, into the forearms and into the tips of the fingers when the ball is released (Brancazio, 1981).


Momentum is needed to exert the force needed to get the object moving to overcome inertia.  In order to change an objects momentum we need to apply force. To accelerate vertically we need larger vertical impulses, this will propel us into the air. Impulse is a production of force and time therefore the greater the impulse the greater the change in momentum (Blazevich, 2010). This principle is more prevalent in the basketball jump shot, however it is still required in the foul shot because momentum is needed to overcome inertia.


What is the ideal projection for a foul shot?

 
 
 
Projection motion is the motion of an object projected at an angle into the air. Gravity and air resistance can impact an object in the air. However, in the majority of case air resistance is considered to be so small, it is disregarded (Blazevich, 2010, p 25). This is the case with the foul shot because most of the time it occurs inside a gym. 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 is the distance the projectile covers and is determined by its projection speed, the faster the speed the further it will go (Blazevich, 2010, p. 25) . Projectile angle is the angle that the object is projected. When an object is projected at angles between 0 degrees and 90 degrees, the object will travel vertically and horizontally. When the angle is greater the object attains greater vertical height but less range (Blazevich, 2010, p. 26). Relative height of projection is the vertical distance between the projection point of an object and the point in which it lands (Blazevich, 2010, p. 26).

 

The angle of the foul shot is determined by the height of the player. Research by Gablonsky and Lang (2005) found that the taller the person, the better the free throw shooter should be. Their height allows them a larger margin of error for the angle of the shot. If a tall player is having issues with foul shooting, it is caused by the player shooting at a wrong angle or inconsistencies in their release angle and release velocity (Gablonsky & Lang, 2005). Shorter basketball players need a larger release angle and this is due to shorter people having to cover more distance vertically (Gablonsky & Lang, 2005). The trajectories that allow the biggest margin of error go through the basket between the center and the back of the rim (Gablonsky & Lang, 2005). The shorter the player, the closer to the back of the rim they should aim (Gablonsky & Lang, 2005). Tran and Silverberg (2008) suggest that the best release for a foul shot is between 52 and 53 degrees and the top of ball’s trajectory is just 4cm below the top of the backboard. The player should aim at the back of the rim so that the gap between the ball and the back of the ring as the ball passes through the ring is about 5 cm (Tran & Silverberg, 2008). The player should release the ball as high above the ground as possible, as long as this does not adversely affect his launch consistency and the player should release the ball so it follows the line joining the player and the basket (Tran & Silverberg, 2008). The player should launch the ball with a smooth body motion to obtain a consistent release (Tran & Silverberg, 2008).

 


The best release angle is between 53-53 degrees
 

 Table 1. Optimum Trajectories for People of Various Heights

Height
Height (m)
Release Angle (°)
5’
1.52
56.64
5’1”
1.55
56.47
5’2”
1.57
56.31
5’3”
1.60
56.14
5’4”
1.63
55.97
5’5”
1.65
55.80
5’6”
1.68
55.63
5’7”
1.70
55.45
5’8”
1.73
55.28
5’9”
1.75
55.11
5’10”
1.78
54.94
5’11”
1.80
54.77
6’
1.83
54.60
6’1”
1.85
54.43
6’2”
1.88
54.25
6’3”
1.91
54.08
6’4”
1.93
53.91
6’5”
1.96
53.74
6’6”
1.98
53.57
6’7”
2.01
53.40
6’8”
2.03
53.22
6’9”
2.06
53.05
6’10”
2.08
52.88
6’11”
2.11
52.71
7’
2.13
52.54
7’1”
2.16
52.37

Source: Gablonsky & Lang, 2005.

 
Why is it important to put back spin on the ball?

Magnus effect is the changing of trajectory of an object towards the direction of spin which is the result from the Magnus Force (Blazevich, 2010). Magnus force is the lift force acting on a spinning object (Blazevich, 2010). As backspin on a basketball increases, the capture area becomes larger (Hubbard & Okubo. 2006). Brancazio explains that back spinning balls experience a greater decrease in translational and total energy than a forward spinning ball when it makes contact with the ring. Putting back spin on a free throw (or any basketball shot) is very important. If back spin is applied on a foul shot, there is more chance of the ball bouncing up and going through the ring, even if the shot is too long or short (Hubbard & Okubo, 2006). A player should release their shot with approximately 3 Hz of back spin (Tran & Silverberg, 2008). 3 Hz translates to the ball rotating backwards approximately three times before reaching the hoop (Tran & Silverberg, 2008). It is actually difficult for a shooter to put more than 3 Hz of back spin on a ball without having a negative effect on the consistency of the shot release (Tran & Silverberg, 2008).

 
What impact does velocity have on a free throw?

The biggest impact on missing foul shots is the velocity of the ball when released. It is more important for the player to use the right velocity as compared to the correct angle of release (Tran & Silverberg, 2008). A study conducted by Mullineaux and Uhl (2010) on college players in America found that slower ball release was found to distinguish misses from swishes in a foul shot. The study found that the change in release speed is caused by the player perceiving the technique to be inappropriate and trying to correct the shot (Mullineaux & Uhl, 2010). By having a release velocity close to the perfect velocity, the foul shooter is able to have a bigger margin of error in terms of release angle. As can be seen in table 2 below, most shooters have an error range of 2-2.5 degrees in their release angle if the velocity of their release is correct.


Table 2. Optimum Release Velocity and Max Error in Angle Release

Height
Height (m)
Release Velocity (m/s)
Max Error (°)
5’
1.52
7.34
2.08
5’1”
1.55
7.32
2.09
5’2”
1.57
7.29
2.11
5’3”
1.60
7.26
2.13
5’4”
1.63
7.24
2.15
5’5”
1.65
7.21
2.17
5’6”
1.68
7.18
2.18
5’7”
1.70
7.16
2.20
5’8”
1.73
7.13
2.22
5’9”
1.75
7.10
2.24
5’10”
1.78
7.08
2.26
5’11”
1.80
7.05
2.27
6’
1.83
7.02
2.29
6’1”
1.85
7.00
2.31
6’2”
1.88
6.97
2.33
6’3”
1.91
6.95
2.35
6’4”
1.93
6.92
2.36
6’5”
1.96
6.89
2.38
6’6”
1.98
6.87
2.40
6’7”
2.01
6.84
2.42
6’8”
2.03
6.82
2.43
6’9”
2.06
6.79
2.45
6’10”
2.08
6.76
2.47
6’11”
2.11
6.74
2.49
7’
2.13
6.71
2.50
7’1”
2.16
6.69
2.52
7’2”
2.18
6.66
2.54
7’3”
2.21
6.64
2.55

Source: Gablonsky & Lang, 2005.

 

How does this translate into a good foul shot?

Taking a foul shot is a whole body technique but most people do not realise this. As the power needed to make the shot comes from the summation of forces, the initial power is created from the legs and sequentially works its way up through the body into the arms. The basketball shot is a push-like motion which helps create force because all joints act together creating a high overall force (Blazevich, 2010). The angle of release is important in a foul shot, but having a sound velocity at the release is more important because it allows for the shooter to have a higher margin of error for the angle of release. Putting back spin on the ball allows for the shot to be either too short or long and still have the possibility to bounce of the ring or backboard and still go through the hoop.

 
Ben Wallace is the worst foul shooter in NBA history. Has made only
41.80% of total foul shots attempted.


 

References:

Blazevich, A. (2010). Sports Biomechanics, the Basics: Optimising Human Performance. A&C Black.

 

Brancazio, P. J. (1981). Physics of Basketball. American Journal of Physics, 49(4), 356-365.

 

Gablonsky, J. M., & Lang, A. S. (2005). Modelling Basketball Free Throws. Siam Review, 47(4), 775-798.

 

Hubbard, H & Okubo, M. (2006). Dynamics of the Basketball Shot with Application to the Free Throw. Journal of Sports Science, 24(12), 1303-1314.

 

Lam, W. K., Maxwell, J. P., & Masters, R. S. W. (2009). Analogy Versus Explicit Learning of a Modified Basketball Shooting Task: Performance and Kinematic Outcomes. Journal of Sports Sciences, 27(2), 179-191.

 

Mullineaux, D. R., & Uhl, T. L. (2010). Coordination-variability and kinematics of misses versus swishes of basketball free throws. Journal of sports sciences, 28(9), 1017-1024.

 

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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