Basketball Form Shooting Biomechanics

A basketball coach may hear and see many descriptions and examples of the proper shooting position. It can be said that the perfect shooting form creates the shot that goes in the basket. Analysis and understanding of the correct shooting form of a basketball player who is stationary is key to perfecting the overall shot. As stated by Hall (2012), Certain kinematic patterns are associated with a high level of skill in the execution of some sport performances (p. 355). When the form is perfect at the top, where there is only movement upward from the lower body and the feet do not leave the floor, it is likely that other ways by which to shoot a basketball will also be effective. It can be said that a form shooting a basketball is the foundation to set shooting and jump shooting a basketball. The shooting techniques of different basketball players seem similar, although the differences are sufficiently significant to the point that each player can be considered to have a unique shooting style (Struzik, et.al., 2014, para. 5). When a player reaches the top of his or her jump, he or she, in essence, becomes a form shooter, as only the motion of the shoulder, arm, and wrist become relevant.

The following evaluation will be representative of the mechanics of the arm movements associated with form shooting a basketball with the strong hand only. In form shooting, the lower body is also used where the knees, hips, and trunk are involved. While in the motion itself, the arm, elbow, wrist, hand, and fingers are also keenly associated with proper technique. This movement must be automated so that, regardless of the external factors, the player achieves maximum repeatability (Struzik, et.al., 2014, para. 2).

Joints Involved

While the form shot is primarily an upper body and hand and arm-specific motion, joints of the lower body play a part in the fundamental biomechanics of the form shot. Hall (2012) posits, The convention for measuring joint angles is that in anatomical reference position, all joint angles are at zero degrees (p. 346). This point is important to keep in mind as one observes and analyzes the angular movements of the joints while engaged in a specific exercise or task. In the form shot, the following joints are employed: knees, hips (trunk), shoulder, elbow, wrist.

Joint Angles and Movements

The convention for measuring joint angles is that in anatomical reference position, is that all joint angles are at 0?° (Hall, 2012, p. 346). Beginning with the knees, they are flexed approximately 85?° degrees to promote upward force while the trunk is flexed nearly 50?°, at the hip. Body segment orientation is measured in absolute relation to a specific plane (Hall, 2012). In this case, the trunk and hip are measured with relation to the vertical plane. In the arm, angular kinematics impact the shot form and release point of a basketball. The shooting arm shoulder and upper arm are held at nearly 45?° parallel to the distal side of the upper body with the elbow abducted approximately 20?° away from the side of the body. If the elbow abducts more than the prescribed distance from the body, the arm will be out of position and the shooting motion may be compromised, thus taking excessive movement to get the shooting arm back into proper position prior to the release of the basketball.

The shooting forearm is at an angle of 90?° to the upper arm and the wrist has an extension angle of close to 90?°, creating a platform on which the basketball will rest. Abduction of the fingers of the shooting hand should be to a position that is comfortable to the shooter and far enough for the ball to rest without movement. Erculi and Supej (2009) state, A smaller elbow angle means a greater flexion of the arm upon ball release and thus a lower position of the wrist and the ball. A larger upper-arm angle with regard to the vertical line means a lower position of the upper arm and thus a lower position of the wrist and the ball (p. 1039).

The shoulder flexes as the trunk and knees extend toward the vertical. As the knees, hips and trunk reach full extension to vertical, the shooting shoulder is flexed to approximately 145?° to 160?°, depending on the dexterity and physiological capabilities of the shooter, while the angle in the forearm and upper arm increases from 90?° to a fully extended 180?° at the elbow. The shooting wrist flexes simultaneously with the extension of the elbow creating the force to shoot the basketball. In basketball, the training of shooting (especially over a longer distance) should also be performed in conditions of moderate and high fatigue so that an appropriate shootingtechniquecan be preserved and result in shooting accuracy (Erculi and Supej, 2009, p.1035). The completed form shot position: Knees-Fully Extended Trunk-Fully Extended, Shoulder-Flexed to 145?° to 160?°, Elbow-Extended to 180?°, Wrist-Flexed to 90?°.

Prime Muscles and Contractions

While shooting a basketball involves a great number of external factors, joint movements and angles as well as muscular contractions, the form shot itself is primarily involved in the upper body and shooting arm specifically. The triceps and biceps are main players in the shot as their job is related to elbow flexion and extension. This phase of the shot is in the set up when the ball is rested upon the hand, the elbow is bent and the triceps are relaxed and the biceps are contracted. Biceps promote the movement of the ball from a position in front of the body to the shooting position.It is when the elbow is extended and the ball is shot that the force created by the contracting triceps helps to propel the basketball toward its target.

Additionally, the deltoid and trapezius are being employed to raise the arm in extension as the ball is lifted into its final release position. The anterior deltoid in conjunction with the trapezius extends the arm. The trapezius contracts as the shoulder shrugs upward in extension of the arm.

The muscles of the forearm are also notably involved. The wrist extensors open the fingers and cause the hand to hold the ball to go back toward the upper arm. These muscles are being activated when the ball is held up in front of the body pre-shot. During the follow-through, the hand snaps downward into a position akin to reaching up onto a shelf and picking up a cup with one's thumb, index finger and middle finger. While there are a number of other muscles working during a routine jump shot in basketball, during the fundamental form shot, the muscles of the arms are those primarily involved and it when the hand goes downward at the end, the wrist flexors are engaged to complete the motion.

Linear and Angular Velocity and Acceleration

The velocity at which the arm is engaged in the process of the shot has a direct relationship to the distance the ball will travel toward the basket. While angular velocity is also related to ball flight, arm angle and the linear velocity correlate directly to the fundamental form shot. Consider the angular velocity (w) of the arm as it is bent at the elbow, biceps contracting, triceps flexing, the radius of the elbow's rotation (r), and the linear velocity (v) of the ball as it leaves the hand. Hall (2012) states that the figure is expressed in terms of the equation:

v = rw

The more that the biceps are able to contract at the point at which the ball is brought up toward the shoulder into shooting position creating the optimum angle to produce the angular velocity to shoot the basketball, the better the potential outcome will be. In conjunction with the biceps contraction, the triceps are then required to contract, creating the radius of rotation. The two create the equivalent of the linear velocity of the ball and its propulsion toward the basket. When employed correctly with the joint angles of the arm, the shot has a higher likelihood to be in the proper trajectory. The force used to shoot the ball is created when acceleration and mass are combined. Newton's second law of motion is an expression of the relationships among force, mass, and acceleration (Hall, 2012, p. 374). It states that force equals mass times acceleration and is represented in the equation:

F = ma

When the player conducts the form shot, the force of the shot itself must be appropriate in relationship to the mass of the basketball for it to be properly accelerated forward and up toward the basket. A player' strength, flexibility, and injuries can adversely affect the process whereby the arm is placed into the correct positions at all of the correct angles. As the strength, flexibility and health of the legs and lower body are obviously involved in the production of a jump shot in basketball so too are those factors in the arms and upper body related to the execution of the proper form shot.

Proper Shooting Techniques and Injuries

Injuries will undoubtedly have a significant effect on the shot. It is unlikely that appropriate angular and linear velocity will be achieved when the muscles of the arm are not strong enough or healthy enough to achieve optimal arm angles. The inability, due to injury, to produce the correct arm angles will be directly reflected by maximum and appropriate velocity of the basketball during the shot. Basketball can cause considerable strain on a player, especially in the arm and shoulder due to the intensive movements of shooting a basketball (Erculi and Supej 2009). This injury potential can be mitigated by proper training, stretching and practice. Not only does injury play a role in proper arms angles, muscle contraction, and potential linear velocity but over use and fatigue also play a role in deteriorating arm optimal arm position while shooting a basketball. Erculi and Supej (2009)

Kinematic analysis was applied to calculate the height of the shoulder and wrist of the release arm, as well as the elbow and upper arm angles, with regard to the vertical line. The study results reveal statistically significant differences between the series of throws in all measured variables. The heights of the shoulder axis and of the wrist both decrease with growing fatigue (p. 1029).

Proper position of the arm and appropriate muscle use and joint angles will help to eliminate this potential fatigue.

In essence, the form shot in basketball is the most basic of the shots. But, when perfected, it becomes the fundamental basis on which all basketball shots are performed. Joint angles, muscle function, angular and linear velocities as well as existing injuries and fatigue all play vital roles in the biomechanics of the form shot. When all factors have been taken into due consideration and/or properly applied, there is a likelihood that the basketball player executing the form shot will be in the correct position, will effectively use the appropriate muscles, will produce the optimal acceleration of the ball and will reduce fatigue and injury.

References

1. Erculi, F. and Supej, M. (2009). Impact of Fatigue on the Position of the Release Arm and Shoulder Girdle Over Longer Shooting Distance for an Elite Basketball Player. The Journal of Strength and Conditioning Research. 23(3): 1029-1036.
2. Hall, S.J. (2012)Basic biomechanics(7thed.). New York, NY: McGraw Hill.
3. Struzik, A., Pietraszewski, B., and Zawadzki, J. (2014). Biomechanical Analysis of the Jump Shot in Basketball. Journal of Human Kinetics. (42): 73-79. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4234772/

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