Kinematics and Projectile Motion
Kinematics is the study of motion. It can be used to describe the initial and final velocities, displacement, speed, acceleration, and/or time using the various kinematic equations. In basketball, kinematics is used to break down the one-dimensional and two-dimensional movement components in skills such as dribbling and shooting.
Kinematics of Running and Dribbling
In basketball, when you have the ball you cannot move anywhere without a dribble or else it will be considered a "travel," which will result in a turnover. Basketball players must be able to move at different speeds while dribbling the ball. A good player must have the ability to quickly accelerate from a low velocity or zero velocity, to a fast velocity in the shortest amount of time possible in order to effectively move around the court. Point guards (the player on the court responsible for bringing up the ball) are required to sprint down the court while dribbling the ball in order to start the offensive play on the other end. The team on offence generally has eight seconds to cross half court or else it will be considered a turn over, so it is essential for all players to be able to know how to use their teammates and correlate their body and the ball in order to dribble up the court and score. Other ways basketball players use kinematics while dribbling is to defeat the defence with various moves that require a change of pace or change of direction. They must know how to control their body in relation to the ball to make the defender shift one way, so that the player can quickly change their direction to go the other way. Effectively changing the velocity/accelerating and decelerating will allow a basketball player to keep their defender off balance making their reaction time slower, which makes it easier to get past them to get to the basket.
The video above shows a girl accelerating from a standing position (zero-velocity) to her maximum velocity in order to dribble down the 28.7m court. These properties (velocity and acceleration) can be described using the following kinematic equations:
The video above shows a girl accelerating from a standing position (zero-velocity) to her maximum velocity in order to dribble down the 28.7m court. These properties (velocity and acceleration) can be described using the following kinematic equations:
Projectile Motion
Shooting a jump shot heavily relies on proper mechanics in order to launch the ball at an angle and velocity that will ensure that the shot released will have the best chance of going in. A basketball player must be able to use their mechanics to jump straight up, extend their arm and follow through using their wrist all in one fluid motion. The ball should be fired at an angle that will travel at a vertical distance above and over rim, reach its maximum height, and accelerate downward into the net, all while maintaining a constant horizontal velocity. The parabolic path of the ball can be described as a two-dimensional, parabolic movement. The horizontal velocity stays the same throughout the entire path of flight, while the vertical velocity decreases as soon as it is initially launched, until it reaches its maximum height where it will then accelerate downward until it is stopped. This allows projectiles such as a jump shot to be launched vertically at an angle to a target (the net) above the release point while moving horizontally. Skilled shooters know how to alter the velocity and angle of release to make shots from anywhere on the court. For example, shooters snap their wrist to follow through faster when shooting a shot farther away from the net in order to acquire the necessary velocity and angle needed to score.
The video above shows the parabolic motion of a standard jump shot and a graph showing its path (please note that the x and y velocity time graphs do not accurately depict the mathematically calculated velocities. Please disregard them when relating the video back to the calculations). In order to find the initial vertical and horizontal velocities of the shot and the angle of the shot, several kinematic equations as well as several trig functions are required.
The video above shows the parabolic motion of a standard jump shot and a graph showing its path (please note that the x and y velocity time graphs do not accurately depict the mathematically calculated velocities. Please disregard them when relating the video back to the calculations). In order to find the initial vertical and horizontal velocities of the shot and the angle of the shot, several kinematic equations as well as several trig functions are required.
Similar kinematic principles of shooting a jump shot apply to passing a basketball. Through the naked eye, passing a basketball may seem as though it travels in a constant horizontal motion, however, most travel in a two-dimensional projectile path just like a jump shot as shown in the picture to the left. Passing requires a force applied to the ball at an angle and the right velocity in order to get the ball to the receiver.