Major Question:
What are the biomechanical principles involved in the optimal basketball jump shot?
Basketball is a sport that was invented in 1891 by Dr James
Naismith at the Y.M.C.A College, in Springfield Massachusetts (Basketball Victoria, 2015). Forty years after the discovery of the game, the basketball jump shot was
developed, which is now considered as the primary skill used in the game of
basketball. Historians have defined a jump shot as when a player vertically
jumps and releases the ball at the top of their jump (Pennington, 2011). As it
is known as the optimal preference for scoring, over 70% of scores during a
game come from the use of a jump shot. The sport of basketball comprises of a
variety of biomechanical elements and it is important to consider these when
shooting an accurate jump shot. In this blog, the biomechanical principles and
movements involved in an optimal jump shot will be thoroughly analyzed.
Followed by an experiment conducted displaying several biomechanical principles
to enhance the success of a basketball jump shot.
The Answer:
Optimal
Technique:
Positioning and accuracy
To generate a successful basketball
jump shot, there are a number of sequences used to produce an optimal
technique. Firstly, the shooter is encouraged to stand with their feet shoulder
width apart to maintain balance and ensure their centre of mass is inline with
the basket. To further enhance shooting accuracy, the athletes shoulder, elbow
and hip are in line with one another. The ball sits in the palm of the
athlete’s hand with the forearm in line at eye level to produce greater
accuracy in the shot as the forearm does not block the athlete’s vision (Miller
& Bartlett, 1996). The shoulder then lifts the ball by flexing to an angle
between 90° and 135°. It is recommended that the shooting arm be
lifted very close to a fully extended vertical position to release the ball. The
movement of the arm, forearm and hand, followed by the alignment of the
shoulder, elbow and wrist simultaneously work together to produce a single
plane of motion. The extension of the ankle, knee and hip joints also occurs simultaneously
as the ball is elevated to perform the jumping motion (Okazaki, 2014). An
elevated release point reduces the distance from the basket therefore
increasing the accuracy of a shot going in. The point of release should be just
before the apex of the jump, driving the momentum of the legs through the arm,
wrist and follow through motion (Okazaki, 2014).
Ball
Rotation / Backspin
 |
| Figure 1. Ball spin influenced by friction |
It is also evident that
the rotation of the ball can be created with the fingertip control, wrist
action and a follow through motion. Sports science (2005) recommends the use of
players “flipping” their fingers under the ball to generate the spin. Using an
appropriate grip and having the forearm aligned vertically, allows for the
shooter to apply backspin on the ball (Knudson, 1993). Wrist extension
emphasizes the motion of backspin and as the ball is being released, the wrist
is slightly hyper-extended. Decreased wrist flexion during the follow through
phase, may influence the wrist velocity and result in a lower ball release and
ball rotation (Okazaki, 2015). Therefore, vigorous wrist flexion at the peak of
the release creates a follow through motion, allowing the overall backspin on
the ball to generate a favorable spin into the basket.
Kinetic
Chain:
A basketball jump shot
incorporates movement pattern within the kinetic chain, known as throw-like and
push-like and can be adopted into an athletes shooting technique. A push-like
movement pattern extends all joints in the kinetic chain simultaneously in a
single movement. A throw-like movement pattern differs, as the joints of the
kinetic chain extend sequentially, one after another (Blazevich, 2013). A less skilled athlete generally begins with a push-like action and progresses to a throw-like.
Throw-like
The throw-like movement
pattern is commonly used during the sequential extension of joints to execute
the throwing action of the shot (Okazaki, 2014). Shoulder and hip rotation,
elbow and wrist acceleration and finger and ball acceleration are the movement
patterns consistently used to perform a jump shot. As an athlete takes a jump
shot and uses a throw-like motion, altogether these joints create momentum
through large muscle forces. Acceleration
of these movement patterns in the kinetic chain generates power for the shot to
reach the distance of the basket (Blazevich, 2013). As the athlete is jumping
in the air prior to releasing the ball, kinetic throw-like energy is
transferred to the arms and hands to produce force and ball acceleration
(Struzik, 2014).
Push-like
A push-like movement
pattern is commonly used in the preparation phase of executing a jump shot. In
the jumping stage of the shot, all joints within the legs, hips, knees and
ankles of the kinetic chain, extend simultaneously in a single movement,
therefore producing a higher amount of force. As the athlete jumps vertically
off the ground, this results in higher overall force, which transfers through
the body of the kinetic chain consequently resulting in an accurate shot (Blazevich,
2013). As the athlete is moving forward towards the basket, the body travels at
a fast horizontal velocity, therefore produces greater momentum for a higher
and accelerated jump. The athlete consequently will generate enough force to
elevate their body off the ground (Alexander, 2010).
Projectile
Angle & Motion:
Projectile angle
The ball projectile angle/release
angle into the hoop is considered to be one of the main factors in completing a
successful biomechanical jump shot. An accurate jump shot can vary in its
release angle due to an individual athletes height, movement patterns, and the
presence of a defender (Blazevich, 2013). A perpendicular projectile angle is
considered to provide a larger area for the ball to fall through the width of
the basket (Okazaki, 2014). An optimum angle of release for a mid to long-range
jump shot is between 50°-70°. As seen in figure 2,
when the shooter is performing a long-range jump shot, the angle of release
decreases due to the amount of power required to control a high projectile
angle.
 |
| Figure 2. Long-range and short range projectile angle |
Release height
It is evident that
maximizing the height of release of the ball increases the accuracy of the shot
and minimizes error of the shot (Knudson, 1993). Consequently, the higher the projectile
arc of the basketball, the increased chance of an accurate shot
being executed. However, if the ball is propelled too high in the air, more
energy is required to produce the shot, therefore decreasing the level of
accuracy (Fontanella, 2006). Consistently practicing a maximized release height
at training will allow the athletes to shoot accurately under the pressure of a
defender and various ranges (positions) on the court (Struzik, 2014).
Release time
The time of the release at
the peak of the jump is considered to increase the overall height of release. On
the other hand, there are external influences that affect how fast the ball in
released from an athlete’s hand. An athlete who releases the ball at a quicker
pace generally does this in the presence of a defender. A quicker release time
gives the defender less time to block the shot therefore creating further distance
between the shooter and the defender, creating a more accurate shot (Knudson,
1993).
Vertical and Horizontal displacement:
Vertical
and horizontal angles range between 0° and 90° affecting the overall accuracy of the shot. “The
lower the release height or the greater the release angle, the greater the
vertical displacement of the ball” (Okazaki, 2014).
Figure 3 demonstrates the level of accuracy when a ball enters the ring at a vertical
displacement compared to a horizontal displacement. Entering at a vertical
angle is considered to be the more effective approach to maximize success when
shooting. “Squaring up” towards the basket generates a stable base of support,
and minimizes horizontal motion of the body to allow the athlete to produce an accurate
shot (Knudson, 1993). On the other hand, a shot performed at a greater distance
does require greater horizontal velocity for the ball to reach the basket.
 |
| Figure 3. Vertical and horizontal displacement |
Newton’s first law:
Newton’s first law states,
“An object will remain at rest or continue to move
with constant velocity as long as the net force equals zero” (Blazevich, 2013).
This first law is also
referred to as the law of inertia; inertia is described as an object’s tendency
to resist any change in its present state of motion, either moving or
stationary (Blazevich, 2013). So the larger the mass of an object, the more
inertia it has and the harder it is to change that object’s state of motion -
inertia (I) is proportional to mass (m) (Benjamin,
2014; Verial, n.d).
In basketball, before
the player has released the ball during a jump shot they must first adjust
their inertia and change their path of motion from a horizontal plane to vertical
to be able to move upwards. To stop, change their direction and accelerated
their path of motion upwards they need to apply internal and external forces by
using their muscles and footwork (Benjamin,
2014; Verial, n.d). Once they have
left the ground the force of gravity will be present, descending the player
back to the ground. The basketball is also affected by Newton’s first law
during a jump shot. Without external forces such as gravity acting upon the
ball once it is released, it will continue to travel in its current direction
until gravity pulls it back down. To be able to find the right trajectory for
the jump shot the player must judge the force of gravity by the weight of the
ball (Benjamin, 2014; Verial, n.d).
Newton’s second law:
Newton’s
second law states, “The acceleration of an object is proportional to the net
force acting on it and inversely proportional to the mass of the object: F =
ma” (Blazevich, 2013).
Acceleration
is produced when a force acts on a mass, which is needed to move and change the
state of motion of an object. The heavier and greater the mass of the object, the
harder and more force will be required to accelerated it. In a sporting
performance it is key to try and maximizing the force produced and minimizing
the mass of the object; specific technical changes can produce more force,
although it can not change the mass of the object (Blazevich, 2013).
This
law can be applied to basketball when players are shooting the ball. As the
basketball has a constant mass, the player must generate a sufficient amount of
force to accelerate the ball towards the basket, where as applying insufficient
force or too much may result in the ball not travelling the required distance
(Benjamin, 2014; Verial, n.d).
Newton’s third law:
Newton’s
third law states, “For every action, there is an equal and opposite
reaction” (Blazevich, 2013).
The third law of motion
closely links in with the second law, and answers how force can be applied to
ourselves. The law indicates that for every force applied to an object it will
have an equal reaction force back in the opposite direction (Blazevich, 2013).
If humans apply a force against an object that does not move e.g. the ground,
it will produce an equal and opposite reaction against us which we can use to
accelerate in opposite direction (Benjamin,
2014; Verial, n.d).
During the shooting
movement in basketball, this law is seen in the jump stage and shooting stage. Basketball
players apply a ground reaction force through their feet against the floor to
create an opposite reaction which propels them upwards into the jump shot. This
vertical downwards force occurs when the foot makes contact with the floor (Benjamin, 2014; Verial, n.d). The equal and opposite reaction also occurs when
shooting the ball (see figure 4); force is first applied to the ball by the
hand to accelerate it towards the basket, an equal and opposite reaction force
then occurs from the ball on the hand. This should make the hand accelerate in
the opposite direction but it does not, due to other forces acting on the
fingers and hand which counteracts the opposite force. The other forces
counteracting the force of the ball to the hand include muscles in the forearm,
which pulls on the fingers and hand (Academy,
2012).
 |
|
Figure 4. Newton's third law - Basketball Jump Shot
(Academy, 2012)
|
Centre of
mass:
Bodies are made up of individual components or
particles that each have its own mass. The weight of a body is the mass of each
individual component combined and their acceleration due to gravity (Blazevich, 2013; (Spathopoulos, n.d).
The centre of mass is determined by the point of which a symmetrical distribution
of weight of each component occurs. In sports performance, manipulating the
body around the centre of mass can be an advantage and difference between athletes
with the same height and skill level (Blazevich, 2013; (Spathopoulos,
n.d).
Balance and keeping the head and eyes forward during the
execution of a jump shot is important to improving accuracy of the shot; this
can occur by manipulating the centre of mass during the jumping stage of the
shot. The centre of mass is raised upwards at first then falls during the jump,
this occurs by lifting the feet up under the body making the upper body
accelerate downwards in relation to the centre of mass; the extension of the
legs accelerates the upper body upwards as the center of mass falls downwards,
as shown in figure 5 below (Blazevich, 2013; Chapman, 2008).
 |
|
Figure 5. Centre of mass manipulated during a jump shot (Blazevich,
2013)
|
Force:
Force is a biomechanical
principle that contributes to the success of an accurate and powerful jump
shot. A basketball jump shot utilizes a sequence of chain movements in the
body, to generate a production of force to jump and release the ball. In order
to produce the greatest amount of power for a jump shot, the shooter must use a
summation of forces starting from their legs and ending at their fingertips (Blazevich, 2013). To
increase power in a jump shot, force is applied to the ground to accelerate
mass upward, transferring momentum in the motion of releasing the ball. The
flexion of the knee when producing force, allows for greater muscle activation,
consequently allowing the athlete to produce a greater amount of force. Flexion
of the elbow is essential in the summation of force process, as regularly
extending the elbow reduces the fluency of the jump shot, resulting in a failed
shot (Miller & Bartlett, 1996). As the ball leaves the athletes hands, a
flick of the wrist motion is the last process of the summation of force. If
this wrist action is not performed it could reduce the accuracy of the shot and
generate too much force (Kentridge, 2003).
Impulse
Momentum:
Impulse is considered as
the product of force and time, and momentum is known as the product of velocity
and mass (Blazevich, 2013). Impulse momentum is a biomechanical principle that
is used to generate a large amount of force when performing a basketball jump
shot. When an athlete is dribbling to the point of their jump shot, their
momentum is moving forward. Sufficiently transferring the horizontal momentum
(running phase) into vertical momentum (jump) will allow the shooter to
accurately balance themselves and shoot a goal. Force and time are incorporated
into the movement and consequently “the greater the impulse the greater the
change in momentum” (Blazevich, 2013).
Muscles and bones enable body parts to move
by working together as levers. Levers are used to produce strength, force,
speed and range of motion (Knudson, 2007). They comprise of three
components:
·
The fulcrum or pivot
point which allows the lever to rotate,
·
Load or force which
is where force is applied
·
The effort of the
force applied by the user (Mackenzie, 2003)
There are also three classifications of
levers depending on where each component is located with class 3 being the most
common lever in the human body (Mackenzie, 2003).
During a basketball jump shot the shooting
arm will act as a level to produce speed and force on the shot; it consists of
two class 3 levels, shown in figure 6. The first lever allows the player to
produce power in the shot as the fulcrum is located at the elbow joint, with
the triceps muscles that connects with the forearm used as the effort to propel
the ball. The second lever that is applied during a jump shot occurs at the
upper section of the arm, the fulcrum lies at the wrist which allows the player
to accelerate the ball towards the basket with a flick of the wrist and shot
with accuracy. The force is applied through the forearm connecting to the hand,
the load is the ball which is held in the hand.
 |
|
Figure 6. Two levers occur in the elbow and wrist during
a jump shot
|
Optimal Technique – Steph Curry:
 |
| Figure 7. Steph Curry shooting sequence |
Steph
Curry is arguably the purest and greatest shooter in NBA history and has
revolutionized the art of shooting by his smooth action, quick release and
deadly accuracy (Fleming, 2014). NBA analysts
and ESPN’s Sport Science have analyzed Curry’s shooting action and consider it to be an optimal shooting technique, with coaches and players using it as a
framework to develop and improve on their own technique.
Curry
has the ability to quickly adjust his inertia and change his state of motion for
a jump shot by stopping and setting his feet in approximately 0.33 seconds; by
not wasting any forward motion it allows his shot to be efficient and repeatable
(Highnessfsk, 2013). His forearm position is
within 5° of vertical and consistently releases his shot as he is rising 0.06
seconds before the apex of his jump (Highnessfsk,
2013). Curry’s
release angle of his shot consistently ranges from 50° to 55° which increases
the entry angle of the basket by 19% compared to a 45° shot release, this is an
important factor to his 3-point accuracy which stands at an impressive 44%
during his career (Highnessfsk, 2013;
NBA, 2016).
His high release angle also enables him to shot over taller opponents. Curry’s
ability to manipulate his centre of mass, increase force production and minimizes
forward momentum lost during his jump enables him to release the ball in 0.4
seconds, the quickest release time ever analyzed on ESPN’s Sport Science (Highnessfsk, 2013). He does this by setting his feet softly
aligned to the target whilst compressing his right knee, hip, torso, elbow and
wrist in a perfect kinetic chain which acts as a vertical spring helping gain
extra force coming into his first stage of his shot (Fleming, 2014).
Experiment:
Does increasing the jump shot distance change the
angle of the shooting arm or the front leg?
A series of tests were
conducted on a sub elite basketball player measuring the shooting arm angle and
leg angle at three different shooting distances commonly used in basketball. As
seen in figure 8 and table 1 below, by increasing the distance of the jump shot
from a short range shot to a mid range shot and finally to a 3-point range the
angle of the shooting arm and angle of the front leg decreases. Six shots were
attempted at each distance to allow for consistency within the data; the
average short range angle of the shooting arm was found to be at 73.5° with the
leg angle at 136°, these angles decreased in the mid range shots with the mean
being 65° and 121° and continued to decrease as the shot distance increased to
the 3-point line with the average angles being 57° and 110°.
The analysis and data
shows that as the shooting distance changes, the performance of the jump shot
may be manipulated by several variables. These variables include the change of
force required from each shot, the demands for greater velocity and momentum,
and potential energy. As the shooting distance increases the amount of force
needed to be generated through the legs and arms needs to increase as well, to
be able to propel the ball over a longer flight path to the basket. The
reaction force of the foot and the deep bend of the legs cause the body to be
pushed forwards and upwards towards the ring, this reaction force continues through
to the shooting arm. By lowering the angle of the legs and deep bend in the
knees it helps conserve vertical momentum as the legs start to straighten into
the jump. These positional changes in the legs at the different distances allow
the player to maximize the potential energy going into each jump shot (Okazaki
& Rodacki, 2012). The differences between angles at the various distances is
due to the loss of force in vertical displacement and velocity needed to propel
the ball, therefore the closer the jump shot is to the basket the lower amount
of force needed.
 |
| Short Range Mid Range 3 Point Range
Figure 8. Shooting arm and leg angle at the three different distances
|
Distance
|
Release Angle (degree)
|
Front foot leg angle (degree)
|
Short Range
|
74
|
136
|
74
|
137
|
|
71
|
137
|
|
75
|
135
|
|
74
|
136
|
|
73
|
135
|
|
Average
|
73.5
|
136
|
Mid Range
|
65
|
123
|
66
|
123
|
|
66
|
117
|
|
71
|
120
|
|
60
|
124
|
|
61
|
119
|
|
Average
|
65
|
121
|
3 point Range
|
57
|
111
|
59
|
110
|
|
58
|
106
|
|
57
|
108
|
|
56
|
114
|
|
57
|
110
|
|
Average
|
57
|
110
|
How else can we use this information?
The information provided in this blog discusses numerous biomechanical
principles and terms that can be applied to many different sports. Although the
information can apply to other sports the primary focus presented is how these
principles are applied to the basketball jump shot. It aims to provide
basketball players and coaches with information that can be used to improve
their jump shot technique as well as understanding why biomechanics are
important to the skill.
The biomechanical principles discussed can be transferred into a range of different sports. Understanding how to optimize force production and generate impulse momentum can be used in the sport of rugby. As an athlete performs a long pass, impulse is applied by moving the hands and body through a greater range of motion. The kinetic chain principle is considered to be the most beneficial for coaches. Athletes, who consider the weight of a shot put to be too heavy, can adopt a push-like movement pattern to produce enough force to accelerate the push. Whereas, a strong and generally experienced athlete, would adopt a throw-like movement to push the shot put. Newton’s three laws are also transferred to other sports, an example in tennis is when the serve requires the athlete to jump vertically to hit the ball, then is forced horizontally towards the net. Netball uses very similar movement patterns when shooting, landing, jumping and pivoting. The stance performed in a basketball shot can also be used in a netball shot, to enhance optimal positioning before a pass or a throw.
Overall there are many biomechanical principles that enhance an athlete’s ability to shoot a successful basketball jump shot. Such principles include the projectile angle, ball rotation, power and acceleration that overall enhance the accuracy of a basketball jump shot.
Reference list:
Academy, K. (2012, September 4). LeBron asks about
Newton’s 3rd Law [Video file]. Retrieved from https://www.youtube.com/watch?v=R8qygu1RUOI
Basketball Victoria | The Home of Victorian Basketball. (2015). Basketballvictoria.com.au. Retrieved from http://basketballvictoria.com.au/?id=61
Basketball Victoria | The Home of Victorian Basketball. (2015). Basketballvictoria.com.au. Retrieved from http://basketballvictoria.com.au/?id=61
Benjamin, D. (2014). How Do the Laws of Motion
Apply to Basketball? Retrieved from http://www.livestrong.com/article/80145-laws-motion-apply-basketball/
Blazevich, A. J.
(2013). Sports biomechanics:
the basics: optimising human performance. A&C Black.
Chapman, A. E.
(2008). Biomechanical analysis of fundamental human move
Fleming, D. (2014). Sports’ perfect 0.4 seconds.
ESPN The Magazine. Retrieved from http://www.espn.com.au/nba/story/_/id/10703246/golden-state-warriors-stephen-curry-reinventing-shooting-espn-magazine
Highnessfsk. (2013, May 15). Sport Science: Stephen
Curry [Video file]. Retrieved from https://www.youtube.com/watch?v=HOiH1eVCggw
Knudson, D. (2007). Fundamentals of biomechanics.
Springer Science & Business Media.
Knudson, D. (1993). Biomechanics of the Basketball Jump Shot-Six Key Teaching Points. Journal Of Physical Education, Recreation & Dance, 64(2), 67-73. http://dx.doi.org/10.1080/07303084.1993.10606710
Knudson, D. (1993). Biomechanics of the Basketball Jump Shot-Six Key Teaching Points. Journal Of Physical Education, Recreation & Dance, 64(2), 67-73. http://dx.doi.org/10.1080/07303084.1993.10606710
Mackenzie, B. (2003). Levers. Retrieved from http://www.brianmac.co.uk/levers.htm
McGinnis, P. (2005). Biomechanics of sport and exercise. Champaign, IL: Human Kinetics.
McGinnis, P. (2005). Biomechanics of sport and exercise. Champaign, IL: Human Kinetics.
Miller,
S. & Bartlett, R. (1996). The relationship between basketball shooting kinematics, distance and
playing position. Journal Of Sports Sciences, 14(3), 243-253. http://dx.doi.org/10.1080/02640419608727708
NBA. (2016). Stehpen Curry Stats. Retrieved from http://espn.go.com/nba/player/stats/_/id/3975/stephen-curry
Okazaki, V. H. A.,
& Rodacki, A. L. F. (2012). Increased distance of shooting on basketball
jump shot. Journal of sports
science & medicine, 11(2),
231.
Okazaki,
V., Rodacki, A., & Satern, M. (2015). A review on the basketball jump shot. Sports Biomechanics,
14(2), 190-205. http://dx.doi.org/10.1080/14763141.2015.1052541
Pennington,
B. (2011). When the feet left the ground. The New York Times. Retrieved 16 June 2016, from http://go.galegroup.com.ezproxy.flinders.edu.au/ps/i.do?id=GALE%7CA253108940&v=2.1&u=flinders&it=r&p=EAIM&sw=w&asid=435568fff723a2d1f4eb09032bc1b271
Spathopoulos, V. (n.d). Center of Gravity. Retrieved
from http://www.topendsports.com/biomechanics/center-of-gravity.htm
Struzik,
A., Pietraszewski, B., & Zawadzki, J. (2014). Biomechanical Analysis of the Jump Shot in
Basketball. Journal Of Human Kinetics, 42(1).
http://dx.doi.org/10.2478/hukin-2014-0062
Verial, D. (n.d). How Do the Laws of Motion Apply
to Basketball? Retrieved from http://healthyliving.azcentral.com/laws-motion-apply-basketball-1095.html
