Playing basketball the way to win is to score baskets by getting the ball to go through the hoop. The basketball jump shot is the most common way of scoring goals but isn’t the only way with lay ups, free throws and dunks also a way of scoring points. The jump shot is the most used style and most important for scoring  points as it can be achieved from in close or out behind the 3 point line. Being able to score a jump shot means the defence will have to defend you greater and can free up space for team mates. We will discuss the biomechanics of the jump shot and what it is needed to succeed in this style of shooting through the biomechanics principles. 

Sub headings
What causes the back spin on the basketball?
Do Newtons three laws apply in the basketball jump shot?
How can educators use this information?

Source espn.go.com

Firstly we will be looking at the stages of the basketball set shot. There is the preparation which is about getting in a position where the player is set and stable. Propulsion is next where shooter uses his legs to gain power to shoot the ball extending from the legs to the arms. Follow through is the last phase of the shot where the shooter releases the ball at its highest point and is extended, aiming the ball at the hoop. While these are the sequences of shooting it is important to recognise that each athlete can have a slightly different shooting style which can be successful in their own right.

source espn.go.com

 Biomechanics of the jump shot

Ball Release

 The ball release in basketball is critical as it allows the shooter to be able to shoot over a defender and get the greatest accuracy. It is vital to have knees and trunk at full extension while having arms fully extended to gain a maximum release point. The player should release the ball at or as close to maximum height of their jump. There are two advantages to releasing the ball at near maximum height, first is that it makes the action of the shot simpler and more consistent and the other is that it maximises the height of release which will make the shot harder to defend or block. After the release the ball is determined by its height angle and speed of release. If the ball is released at a height below the basket, which most shots will be, the angle of release will have to be greater than 45º (Secretsofshooting.com, 2014). When the shot is released it is vital that the wrist is flicked as it gives aim to the ball as it is released. The ball release of each shooter will change and developing the basic biomechanics will help give guidelines and cues to develop a learner’s game as they develop greater skill and find a solid release point that works for them. The forces on the ground produce linear momentum of the body plus the ball, while the actions of the shoulder, elbow and wrist produce forward and upward momentum of the ball. 

Ball rotation 

The shooter needs to allow spin on the ball or it will just hit the ring and go in any direction. A shooter should be using  backspin on their shot as it will increase the chances of making the ball go into the hoop and increase accuracy as it stays in flight and allows for better chance of the ball hitting the basket and dropping in. The difference between getting a lucky bounce on the ring and the ball firing off in any direction for a miss can often be the amount of backspin you put on the basketball when you shoot it. Backspin on the ball helps the ball bounce forward into the net after coming in contact with the basket. The shooter should have their preferred shooting hand underneath the ball, while the fingers are spread evenly facing upwards. This allows your hand to make the biggest impact when coming to how much spin you want to place on the shot. As you release the ball your fingers will implement the amount of spin placed on the ball at the point of release. The ball is designed to spin back off the ring of back board if the ball doesn’t go in because of the texture and design of the ball. When spin is placed on the ball it causes it to back spin, due to the force affecting the change of direction when hitting the backboard. The downward reflection of the ball accelerates because the lift forces not only act downward with gravity, but backward(Knudson 2007). 

Body position 

Having a stable and controlled body position is essential for taking a jump shot in basketball.  The centre of mass needs to be equal and stable to give the shooter a solid base and allows for when the body moves to shoot the ball. As the shooter jumps they are using Newtons third law of for every reaction there is an opposite reaction. If the shooter quickly applies force straight down, the ground reaction will propel them straight up and allow the shooter to be able to jump (Blazevich, 2010). As the shooter is facing the basket it is vital that the shooter’s body position stay firm and upright allowing for a maximum release point. For a right hander the right foot will generally face directly at the basket while being slightly in front of the left food at shoulder length apart. Coaching literature is fairly consistent in advising athletes to "square up" the body to the basket and jump vertically.  The base of support should be slightly less than shoulder width, slightly staggered with the shooting side foot forward, and with both feet slightly pointed outward to provide the most stable base for the jump shot (Knudson, 1993). The slightly staggered stance allows the shooter to be able to minimize forward or backward motion of the body while they are jumping and maintain side to side alignment of their body with the hoop. It is important to keep in mind that each shooter may have a slightly different stance and body position. This allows the shooter to be stable and balanced when shooting the ball and means they just have to shoot the ball straight as the body is in line with basket. Players with a higher skill level have the ability to be accurate with a less horizontal shift in their centre of mass during the shot.

Force 

When shooting as you get closer or further away from the basket, the amount of force and power changes. As each shooter is different in their strength, some shooters may be able to generate enough power through just their arms while others will have to rely on the power generated through their legs to be able to make the distance and maintain accuracy. Power is generated by utilising different parts of the body and using larger muscles to fuel the little muscles creates force summation. In the basketball jump shot force summation is very important for accuracy and power. The power for the shot comes from the build-up of energy through all the muscles used in the shot. The more muscles used and force exerted into them the more power the shot will have. The legs bend and extend then the whole arm extends with a flick of the wrist to transfer the forces into the ball to give it the power and speed needed to make the distance. The amount of force needed in some shooters will greatly affect the accuracy they are able to place on their shot. To accelerate vertically we need larger vertical impulses (Blazevich, 2010). It is important to use all muscles from smallest to largest to get correct height and distance in shot. The power/force needs to be in time and can't be rushed as it will affect the shooters accuracy.   

What causes the spin on the basketball?

The Magnus Effect is the effect that is placing the spin on the basketball as it is travelling through the air. As the ball is travelling through the air it is spinning a boundary layer of air that collides with air passing next to it. The collision causes the air to decrease which creates a high pressure area. As this is occurring, on the other side of the ball the boundary layer is moving in the same direction as the air which it is currently going in the same direction as the air passing by so no collision is happing. Therefore the air moves faster with all of this creating a low pressure area. With the pressure differential high on one side and the low on the other side it creates a lift force (Magnus effect) that causes the ball to move in the direction of the pressure.

In basketball this allows the ball to dip towards the basket by using the Magnus effect and backspin because it is changing its direction. The downward reflection of the ball accelerates because the lift forces not only act downward with gravity, but backward (Knudson 2007). Spin is a vital tool in the basketball jump shot and can be used not just in shooting but passing as well so it is important for athletes to practise and gain a solid understanding of the different sorts of spin they can use. 

Source (Aviation-for-kids.com, 2014)

Do Newtons three laws apply in the basketball jump shot?

Isaac Newton laws of motions are the three physical laws that laid the way for classical mechanics. His laws describe the relationship between the body and the forces that act upon it and the motion to the forces.

First law: An object will remain at rest or continue to move with constant velocity as long as the net force equals zero (Blazevich, 2010). When a basketball shooter shoots the ball there are several external forces that will affect the ball. Gravity is the biggest effect on the ball as it is pulling the ball back down to earth so the shooter needs to judge the force of gravity by finding the right line of trajectory so the ball can get to the basket. Air is also effecting the balls flight and causes a drag. This isn't as big when playing indoors but can affect heavily in outdoor basketball.

Second 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). The greater the mass of an object being accelerate the more force needed to accelerate that object so in basketball the mass of the basketball will affect the amount of force needed. For younger ages the basketballs are a smaller mass as younger ages can't get the force needed when using a heavier ball. Basketballs can vary in  mass and even the slightest difference means that the player must use the appropriate amount of force when shooting or passing.

Third law: For every action there is an equal and opposite reaction (Blazevich, 2010). Action- reaction is what allows athletes to be able to jump up and shot their jump shot. As the shooter pushes down their force into the floor of the court shooters can't move it because the floor is such a large mass. This allows the shooter to be propelled upwards because the force from the floor is in opposite direction that the force is applied back.  

How can educators use this information?

Using this information it will allow educators to be able to help with teaching students the fundamentals of the basketball jump shot while also being able to give advice to help the more developed students.  By understanding the main biomechanics of the jump shot educators can help change and give skill cues to help learners develop their techniques. Educators don't need to fully change someone's  technique but they can give skill cues and the demonstration of a basic fundamental steady jump shot. 

Reference List
 

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Blazevich, A. (2010). Sports biomechanics, the basics: Optimising human performance. A&C Black

Espn.go.com,. (2014). ESPN: The Worldwide Leader In Sports. Retrieved 10 June 2014, from http://espn.go.com/

Knudson, D. (1993). Biomechanics of the basketball jump shot—Six key teaching points. Journal Of Physical Education, Recreation \& Dance, 64(2), 67--73.

Miller, S., & Bartlett, R. (1996). The relationship between basketball shooting kinematics, distance and playing position. Journal Of Sports Sciences, 14(3), 243--253

Salehian, M., Yasrebi, B., Afkhami, I., Zehsaz, F., & Fazlollahi, S. (2011). Influence of Attentional--Focus on Center of Mass Displacement of Body Different Segments in Basketball Set Shot. Annals Of Biological Research, 2(3).

Secretsofshooting.com,. (2014). The Physics of Shooting | Secrets of Shooting. Retrieved 1 June 2014, from http://www.secretsofshooting.com/the-physics-of-shooting

Spina, M., Cleary, T., & Hudson, J. (1996). An exploration of balance and skill in the jump shot, 294--297