What are the biomechanical principles linked to maximising accuracy on the basketball jump shot whilst imparting sufficient power?

Jump shot definition: a shot at the basket made by a player releasing the ball at the highest point of a leap (Collins English Dictionary, 2003).

The Answer

Force

There are many different biomechanical principals that contribute to the effectiveness of a jump shot in terms of its accuracy and power. One of these is force. Force can be looked at in a number of different ways when relating to a jump shot. For example, there is the production of force that the shooter uses to release the ball, and then there is also the application of force to the ground in order for the shooter to start the jumping motion.

According to Wuest and Butcher (2009) “Body force is produced by the actions of muscles. The stronger the muscles, the more force the body is capable of producing. However, the force of the muscle group or groups must be applied in the same direction and in proper sequence to realise the greatest force.” (p. 237)

This leads to an important biomechanical principal, which is the summation of forces. In order to impart the most power on the basketball the shooter must use a summation of forces starting from their legs and concluding right at their fingertips as they release the ball. As a result of an increase in power being added to each muscle group from the one before it the wrist and fingers will be able to push the ball a lot further than they would have been able to if they were the only muscle groups involved.

Image 1, Source: Unknown Author i

Image 1 shows the summation of force, which begins in the calves and moves through the quads, trunk, shoulder, bicep, tricep, and wrist before being applied to the ball by the fingers.

The jump shot is defined as a shot where the ball is released at the highest point of the jump. In order for a player to leave the ground and take their shot they must apply sufficient force to the ground to create upward reaction force. Newton’s third law states that “ For every action, there is an equal and opposite reaction” (Blazevich, 2012, p. 45). Force is measured in newtons and can be calculated by the formula F (force)=m (mass) a (acceleration). Acceleration on earth is 9.81 metres per second (or approximately 10) due to the effect of gravity.

So for someone with a mass of 80kg the equation to calculate their weight (mass is the amount of matter in an object, weight is the effect of gravity on matter, it is measured in newtons) looks like this.

F = 80 x 10m.s

F = 800 N

So in order to get off the ground an 80kg person must direct more than 800 N (typically it will require a lot more to do a significant enough jump to perform a jump shot) of force into the ground in order to create a reaction force that will send them into the air. (Blazevich, 2012, p. 45)

Wuest and Butcher (2009) state that “ Force from the legs must be applied to the ground such that the upward reaction force from the ground is directed through the centre of mass of the body” (p. 238).

It is important for the shooter to have their feet shoulder width apart as they start to jump so that their centre of mass stays along the midline of their body. If they are leaning to either side, or to the front or back, then their body will travel in that direction as they leave the ground and they will not jump as high. Jumping straight up vertically also helps with the accuracy of the shot as the body stays more balanced in the air and the shooter will be able to keep their eyes fixed on the ring.

Image 2 illustrates the principals of force being created from the legs and also upward reaction force. It also shows the importance of keeping the centre of mass along the midline of the body. The red arrows show the direction that force is applied to the ground from the legs and the green arrows show the direction of the upward reaction force that is created by the initial downward force. A force plate attached to a wall can measure the leg press force output.

Image 2, Source: Unknown Author II

Levers

“Levers enable one to gain a mechanical advantage by producing either strength or range of motion and speed” (Wuest & Butcher, 2009, p. 236). When shooting a basketball using the correct technique the arm with which the ball is shot will act as a lever and help increase power in the shot. All levers consist of three things:

·      

•     A fulcrum or axis around which the lever rotates
• ·      A force arm, which is measured by the distance between the fulcrum and the place where the force is applied
• ·      A resistance arm, which is measured by the distance between the fulcrum and the place where resistance is applied (Wuest & Butcher, 2009)

There are three different types of levers in the body, first class levers, second class levers and third class levers. The jump shot uses two third class levers. The third class lever shown in Image 3 is used to gain power in the jump shot and has its fulcrum in the elbow joint, the effort where the tricep muscle connects to the forearm and the load where the ball is held in the hand.

Image 3, Source; Unknown Author II

This lever works as the tricep muscle moves from being in an eccentric contraction as shown in image 3 to a concentric contraction once the arm has straightened out as the ball is released. The tricep actually connects to the forearm via a tendon just above the elbow joint, which is what makes this a third class lever and not a first class lever.  

The second type of lever used in this technique has more to do with the accuracy of the shot. It is another third class lever that is similar to the first one but has its fulcrum in the wrist, its effort where the tendon from the forearm connects to the hand and its load where the ball is held in the hand.

Image 4, Source: Unknown Author II

This lever is what helps to guide the ball off the middle and index fingers as the shot is completed. As the wrist muscles and tendons go from eccentric contraction to concentric contraction they pull the wrist upwards and make it follow through linear to where the forearm is facing.

Haefner (2008) discusses the importance of effectively using this lever in jump shooting technique.

·      

•     Your elbow and wrist should extend in a straight line to the basket.
• ·      Your shooting hand should extend in a straight line to the rim.
• ·      Hand position on delivery is very important. The ball should come off the hand with perfect symmetrical backspin.”

Image 5, Source: Breakthrough Basketball

Image 5 illustrates the importance of the third class lever in the wrist, which enables the shooter to release the ball and have it travel linear to where the forearm and wrist were facing.

Projection Angle

The power required for a particular jump shot and also the accuracy of the shot are largely affected by the projection angle/release angle.

“The maximum range of a projectile is determined partly by its angle of projection. When the angle is greater, the object attains a greater vertical height but lesser range. When the angle of projection is too small the object doesn’t have sufficient vertical velocity to attain significant range.” (Blazevich, 2012, p. 26)

Okazaki and Rodacki state that “the release angle and entry angle of the basketball into the hoop are directly related to each other” (2012, p. 321). Therefore the angle of projection has significant importance on the accuracy of a jump shot.

Figure 1,Source: Okazaki & Rodacki

As can be seen in Figure 1, when the entry angle decreases so does the target size (indicated by T). The optimum angle of release for a mid to long range jump shot is between 50-70 degrees. When in close to the basket the shooter will be able to release the ball at a higher angle which requires more power and gives the ball a greater entry angle. However, when they move out further from the basket the angle of release will decrease because the power required for a high angle of release is too much to perform with control. The height of release also has a big influence on the angle and power required in the release. For the example shown in Figure 2 we are assuming that the angle of release is 7ft from the ground.

Figure 2, Source: Advantage Basketball Camps

Figure 2 shows how when shooting a jump shot from further away the shooter will have to release the ball at less of an angle than they would have in close even though we know from Figure 1 that this decreases the target size of the ring. This is done because as Figure 2 shows, if the shooter was to maintain the same 70-degree angle of release when further out as was used in close, the arc of the shot would be a lot greater. Whilst this greater arc would allow for a bigger target zone at the ring it requires a lot more power and in the process of producing that extra power accuracy is likely to be lost.

How else can we use this information?

The topic question for this blog revolved around assessing what biomechanical principals are used in a jump shot to gain accuracy and power. The three principals discussed above in the answer are ones that can be applied to many different sports.

For example, the notion of force being used in two ways while performing a jump shot may be helpful to someone who is playing a sport that requires vertical leaps or some sort of throw. A high jumper might take this information and measure the amount of force that their leg press can produce as well as the weight of the body. They can then train to improve this number knowing that it will lead to an improved vertical leap. Or similarly, a shot putter may use this information to better understand that they will be able to maximize the amount of force through their arm by using a summation of forces in the right order starting from their legs.

Levers are also beneficial to basketballers and other athletes who may have read this blog. The answer above concludes that the jump shot uses two different levers, which both help in gaining power, and accuracy. This information could be applied to other sports by isolating where levers are used for a particular skill, and then working to increase the strength of the muscles that provide the effort for that lever.

The projection angle and trajectory of an object (in this case the basketball) is something that is important in a whole different range of sports. Understanding the importance of the angle of release may help a javelin thrower to increase the distance of their throw even without gaining any strength in their arm. Similarly if a netball shooter were to view this blog they would be able to understand that when in close to the basket it is beneficial for them to shoot a high arcing shot, from a high angle of release, in order to give themselves the biggest target zone.

Perhaps the most important way that the information presented here can be used, is to encourage others who seek to perform a biomechanical analysis of a skill to use photographic and video footage to assist them. Taking photos of a skill in action or watching the skill played back in slow motion allows you to analyze the biomechanical principals that it involves better than you could by just watching it live. 

A good way for an athlete to use this information to improve their jump shot would be to apply the principals learnt here in a 5 step biomechanical intervention. According to Blazevich (2012, p. 210) “A detailed plan is very important in order that the most influential biomechanical flaws are noticed and corrected.”

Word Count, 2,065

References

Blazevich, A., J. (2012). Sports Biomechanics the Basics: Optimising Human Performance. Bedford Square, London: A&C Black Publishers Ltd

Collins English Dictionary. (2003). The Free Dictionary: jump shot. Retrieved from http://www.thefreedictionary.com/jump+shot

Figure 1, Okazaki, V. & Rodacki, A. (2012). Schematic representation of the vertical virtual target. Retrieved from http://www.jssm.org/vol11/n2/5/v11n2-5pdf.pdf

Figure 2, Advantage Basketball Camps, Advantage Basketball Camps Shooting camp(image). Retrieved from http://www.advantagebasketball.com/shootingcamp.htm

Haefner, J. (2008). Proper Basketball Shooting Technique, Fundamentals, and Form. Retrieved from http://www.breakthroughbasketball.com/fundamentals/shooting-technique.html

Image 1, Unknown Author I. Bleed Basketball (image). Retrieved from http://ibleedbasketball.com/category/developing-your-game/

Image 2, 3, 4, Unknown Author II. Stick This Graphics (image). Retrieved from http://www.stickthisgraphics.com/Jump-Shot-Silhouette-Decal-Sticker-BSKT17.htm

Image 5, Breakthrough Basketball. Breakthrough Basketball (image). Retrieved from http://www.breakthroughbasketball.com/fundamentals/shooting-technique.html

Okazaki, V. H. A., & Rodacki, A. L. F. (2012). Increased distance of shooting on basketball jump shot. Journal of Sports Science and Medicine, 11, 231-237

Wuest, D. A., Butcher, C. A. (2009). Foundations of Physical Education, Exercise science, and Sport. New York, NY: McGraw-Hill