Introduction

The Basketball Jump shot

The object of basketball is to score more points than the opposition by having the ball travel through your hoop. There are different ways in which players achieve this, the most common techniques are dunking, lay-ups and jump shooting.

The jump shot is a one of the most difficult skills to complete in basketball because unlike dunking and lay-ups the range of the jump shot is further from the hoop which increases the margin for error. However it is also one of the most important as the jump shot technique is the most prevalent technique used accounting for around 70% of shots taken (Struzik, Pietraszewski & Zawadzki, 2014).Throughout the National Basketball Association (NBA), which is widely regarded as housing the best basketball players in the world, there are different jump shot techniques used among the players. Though there are different techniques used there are some factors which can ascertain as to why some players are more effective Jump shooters compared to others.

The three phases of shooting

The preparation phase:   

The initial sequence involved in jump shooting focuses on being balanced. Balance is critical in determining whether the skill will be completely successfully. The player should be ‘squared’ towards the target with the centre of mass directly over their base of support. By aligning themselves with the desired direction of target the players balance is more stable which enables greater accuracy and promotes no horizontal movement during the jump phase (Coachlikeapro.com, 2015). The use of a staggered stance and a vertical jump are the coaches’ focus during this phase to emphasize accuracy (Knudson, 1993). The staggered stance was found to be more successful at minimizing horizontal movement during the jump which in turn allows for greater balance (Knudson, 1993)

The shooting phase:

During this phase the player is using multiple movements in order to achieve the desired result. From the feet through to the fingertips the body should move in a smooth action as a summation of forces to allow maximum force to be placed on the ball whilst maintaining accuracy (Okazaki & Rodacki, 2012). The lower leg muscles, torso and arms are used to generate power for the shot, whilst the forearm, elbow, wrist and fingertips are used to guide the ball in desired direction. Similar to the preparation phase balance is crucial, however during this phase the projection motion of the basketball plays a greater role in determining success. Based on the distance from the target and defensive pressure applied, the height of release, angle of release and speed of released need to be adjusted. The constant technique cue for this phase is to ensure the elbow and wrist extend in a straight line towards the basket.

The Follow through phase:

The follow through phase involves ‘snapping’ the wrist after the ball has left the hand then landing back over the centre of mass to keep balance. Follow through of the shot promotes backspin as evidenced by sharp movement of the wrist and fingertips. Sustaining the final posture as gravity impacts you and allows you to land safely.

Newton's three laws of motion

1. Newton’s 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)

This first law is also referred to Newton’s Law of inertia. This law implies that all objects with a mass have inertia and the larger the mass, the more difficult it is to change the objects state of motion (inertia) (Blazevich, 2010). In order to change the state of motion of an object, we need to apply a force. Newton’s first law applies to the basketball jump shot in relation to how the athletes propel themselves off the ground and into the air as well as the motion of the ball itself.

The aim of a jump shot is for the athlete to get an edge and gain extra elevation over the opponent. In order to achieve such a shot the athlete needs to adjust their movement to a vertical motion.

The ball itself also applies to this first law of motion due to several external forces acting upon the ball (Ville, 2011). If these forces did not exist the ball would continues to fall in the direction it was already travelling. The external forces acting on the ball when playing outside are gravity, air and wind which is known as 'drag' on the ball. Gravity acts as an external force due to the fact it pulls the ball down (Ville, 2011).

Figure 1.1 – The picture above is a visual example of the jump shot being executed. The athlete has propelled himself vertically off the ground in order to extend the shot over the defender.

Newton's second law comes into play when considering the change of the ball and athletes state of motion, e.g. In order to vertically jump higher the equation of 'force equals mass x acceleration' needs to be studied (Blazevich, 2010).

2. Newton’s 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” (Blazevich, 2010). F=m x a

Force needs to be applied in order to change the state of motion of an object, which then produces acceleration (Blazevich, 2010). Newton’s second law states that “the lighter the object the faster it will accelerate” (Blazevich, 2010). The greater the mass of an object the greater the force needed in order to accelerate the object for example, depending on the mass of the ball the force will need to be adjusted in order for the ball to travel the same distance (using a tennis ball rather than a basket ball to execute a jump shot). Isaac Newton’s created an equation in order to calculate the second law as Force = mass x acceleration (F=m x a).

In basketball athletes constantly use force whether it is passing the ball or when shooting for a goal. When executing a jump shot the athletes act as the force whilst the ball equals the mass and cause acceleration. This means that the athletes need to use a suitable amount of force when shooting the ball because when the incorrect force is applied it will lead the ball to go in another direction as to where the ball was suppose to fall (Ville, 2011) In relation to the jump shot when the ball is released (accelerated) out of the hands, this caused the ball to gain momentum (Dr Simonetti, J., 1994).

The equation of F=m x a also proves that in order to increase acceleration of an object, a bigger force needs to be applied (Blazevich, 2010). Newton's third law needs to be considered as every action has an equal reaction.

3. Newton’s third law:

“For every action, there is an equal and opposite reaction.” (Blazevich, 2010)

Newton’s third law relates closely to Newton’s second law as it relates to the concept of force being applied to any object. Newton's third law is apparent every time there is a force applied, as there is an equal and opposite force applied back. The idea of every action having a reaction is what enables the athlete to propel themselves off the ground into a vertical jump. When the athlete bends their knees in preparation to execute a jump shot, they send force into the ground (Ville, 2011). Both Ville (2011) and Blazevich (2010) acknowledge that due to the ground having greater mass than the athlete the force travels back to the athlete and propels them straight up, which allows them to jump straight up in the air (Ville, 2011).

In terms of applying Newton’s third law of motion when taking a shot for goal, the focus is on the athlete and the ball.  When the ball is placed in the athlete’s hands, the athlete’s hands act as the force, which is applied to the ball. When the force is applied the ball reacts and creating a force against the athlete’s hands.  Because the mass of the athlete is greater than that of the ball, the ball propels itself forward whilst the athlete remains in the same position (Dr Simonetti, J., 1994).

Figure 1.2 – This picture above is a visual demonstration of the equal and opposite direction between the player and the ground. In the first frame the force is applied by the athlete when bending his knees and pushing himself into the ground. Due the greater mass of the ground the force flows straight back into the player, which results in a vertical jump, frame 3.

Figure 1.3 – This picture above is a visual demonstration of the equal and opposite reaction of the ball and the athletes hand. The force applied by the hand is what accelerates the ball upwards. The equal and opposite force is the force that the ball is applying to the athletes hand.

Centre of mass

Centre of mass is a major contributor to the performance of any athlete. Prior to shooting the ball, the stability and balance of the athlete is a vital factor in success of shooting percentage. Aspects such as core strength and base stability have large influences on the of the centre of mass. Gravity impacts the centre of mass based the stability of the athlete according their base of support.

Figure 2.1

Figure 2.1- The picture above is an example of how the stability of an object can be affected depending on the position of its centre of mass. This demonstrates that the further away (higher) the centre of gravity is from the base of support, stability decreases for the object. Where as the closer (lower) the centre of gravity, the more stability the object gains.

In basketball the jump shot is one of the most used shooting form. Accuracy is extremely crucial to achieve such a shot and this is the reason as to why ‘low horizontal mobility and high stability’ need to be recognised (Spina, et al, 1995).

Figure 2.2

Figure 2.2- In the picture above Ray Allen is executing a jump shot. From the sixth to the ninth frames it appears as though Allen is ‘hanging’ in the air whilst taking his shot for goal. The five frames beforehand will help explain how it allows Allen to perform such a shot. From the first to fifth frames Allen is running up into his jump shot, he stays low towards the ground allowing his centre of mass to gain stability and balance. Frames four to six demonstrate the legs starting from a coiled position to rapidly extending the legs out, in order to push the upper body upwards, whilst the body’s centre of mass falls. Due to gravity Allen begins to fall back toward the ground so he rapidly extends his legs back down, ‘as his upper body moves upwards’ in order to conserve momentum (Blazevich, 2010). Due to the centre of mass moving in a downward motion and the upper body moving upwards, Allen is able to almost hang in the air, and remain stable (Blazevich, 2010).

Summation of forces

Summation of forces

One of the key aspects many of the greats NBA players talk about when referring to jump shooting is rhythm. The rhythm of jump shooting is important as it allows for a smooth transition from the preparation phase through to the shooting phase and finally to the follow through phase. This combination of phases is known as a summation of forces which is critical in achieving success when shooting a jump shot. Okazaki & Rodacki (2012) explained how by releasing the ball just prior to the apex of the jump, the accumulated force from the lower limbs can be transferred to optimize force in the upper limbs movement patterns of the jump shot.

 Figure 3.1: The above image of Ray Allen, shows the transfer of force from the lower legs through to the fingertips. The sequence of force proceeds as feet, ankles, calves, quadriceps, trunk of body, shoulders, forearms, wrist then finishing at the fingertips.

The summation of forces is pivotal to Jump shooting when the distance from target increases. This combined movement pattern promotes greater force application without sacrificing accuracy, which based on research by Okazaki & Rodacki (2012) is due to the speed-accuracy trade-off.

The link below is footage of Larry Bird competing in the 1988 3 Point Contest. Bird was considers at the time one of the best players in the league due to his combination of size skill set and deadly jump shot. Notice around the 35 second mark, the commentators begin talking about Bird getting into a rhythm then, after making consecutive shots about being in a ‘good groove’. 

Video 1.1

Projection motion

Projection motion

In basketball the release angle of the ball plays a huge role in determining a missed shot compared to a successful shot.

Figure 4.1: This picture of Stephen Curry shooting a Jump shot highlights the impact or change vertically jumping has on the shot. By jumping the height of release is increased making the shot harder for the defender to reach thus decreasing the chance of stopping the shot.

Angle of release

Shoulder extension before release: The angle of release effects the trajectory in which the ball will travel during the shot which in turn effect the force applied to the ball. Just prior to the apex of his jump Curry extends his forearm from the elbow to create force. This force is transferred onto the ball in order to create the trajectory towards the basket. But it is the extension of the shoulder which has the greatest impact on the angle Curry shoots the ball. Due to the height of the landing point (the basketball ring) being higher than the release point of the shooter, the optimum angle of release is greater than 45%. This is due to relative height projection (Blazevich, 2010). As the distance from the hoop increases the angle of release decreases in order to achieve horizontal range. This lower angle compensates for the need to create greater force when shooting longer distances, as the greater the force applied the greater negative effect is has on the accuracy of the shot (Okazaki & Rodacki, 2012).

Figure 4.2 (Okazaki & Rodacki, 2012): The effect of the angle of release also impacts the other end of the trajectory path. As seen above the greater the angle of entry by the basketball to the hoop the greater area it can move through.

Steph Curry average angle of release for three point attempts is around 50-55% which supports Okazaki & Rodacki (2012) by increasing the target area at the other end of the parabola. 

Height of release

Shoulder extension at release point: The height of release is an important aspect of the jump shot as it provides the greatest advantage for the offensive player when being defended. By increasing the height of release it greatly reduces the impact a defender can have by blocking the shot. There are numerous factors which impact on the height of release for basketball players namely the height of the shooter and where the shooter releases the ball from. Of these two factors the extension of the shoulder is the most dominate factor in determining how high the ball is released form the players original starting point.

Projection speed

Extension of forearm prior to apex of jump: projection speed effects the range in which jump shooter can shoot. In basketball players can gain either two points or three points, the trade-off for scoring three points involves having to score the basketball from further away. Thus the speed of release greatly effects the shooter based on the distance he or she is shooting from. Okazaki & Rodacki, (2012) explain how the velocity in which the forearm extends from the elbow has the greatest impact on how much force is applied to the ball when shooting. The emphasis on impulse generation during this movement pattern is detrimental to the accuracy of the shot due to the speed-accuracy trade-off theory (Okazaki & Rodacki, 2012). Therefore players like Steph Curry must be able to generate force to the ball without sacrificing accuracy by strengthening the muscles in his arms.

Ball Rotation (Backspin)

There are many factors that need to be considered when executing a jump shot, and ball rotation is one of them. The most effective technique used to create backspin is the forearm extension from elbow and the flexion or ‘flick’ of the wrist. When performed correctly both these aspects will create backspin.

Figure 5.1

Figure 5.2

Figure 5.1 and 5.2 - When the Steph Curry prepares to execute a jump shot he brings the ball upward keeping the ball close to his body. The ball rests on the base (circle) of the palm on the shooting hand allowing for a swift set up as well as stability and balance (Splash Lab, 2014). Sharp flexion of the wrist leads the ball upward to the fingertips, maximising control and ‘feel’ for the shot and then releasing with a ‘snap’ of the wrist towards the basket. This creates backspin of the ball (Baldwin, 2012). Backspin may not be commonly recognised as a ‘crucial’ aspect of the jump shot, but it is important to consider different aspects that promote greater accuracy of the shot. Keeping the elbow close to the torso will create a smoother release of the basketball and follow through (Furr, 1986). This smooth release will generate backspin on the ball, which then improves the accuracy of the shot (Furr, 1986).

Figure 5.3

Figure 5.3 – When executing a jump shot, backspin is important due to the fact that it helps gain control over the ball. If backspin is not produced the ball is more likely to bounce off the ring in any direction. Research conducted by Alexander (1990) states that “The backspin applied to the ball in a jump shot serves to decrease the horizontal velocity of the ball if it strikes the rim, or causes the ball to deflect downward if it strikes the backboard.” Researchers Yates and Holt (1982) discovered that that quantity of backspin applied to the ball is a major factor statistically related to achievement of getting the ball through the basket (Knudson, 1993). The most influential aspects of achieving a successful jump shot is the wrist action and keeping your forearm vertical, which assists in throwing a straight shot as it creates backspin (Knudson, 1993). In order to achieve optimal ball rotation the follow through must be completed accurately. Incomplete follow through indicates that wrist flexion is slowing rather than climaxing (Knudson, 1993). Ball rotation is essential when executing a jump shot as it helps decrease the velocity of the ball and gain control (Knudson, 1993).