Motion Analysis – Jump Shot
The moment the subject’s feet are planted on the ground, flexion of both shoulders occurs until the tricep muscle is parallel to the ground. At this point, it is important to note that the elbow in the beginning of the set-up is already in flexion, forming a right angle between the forearm and upper arm. The wrist hyperextends so the ball is resting in the palm of the subject. In this case, the subject is right handed, so the ball rests primarily in the right palm while the left hand provides support. At this point, the subject is ready to jump.
Four joint actions occur simultaneously at this time. Both knees, ankles, and the hip extend as the subject pushes off the ground, and the elbow flexes a little further back. When the subject is in the air, the dominant elbow extends and the ball starts to roll towards the tip of the fingers. When the elbow is almost entirely extended, the wrist begins to flex, which is when the release occurs and the ball leaves the palm of the hand towards the basket. After the release, the subject is drawn back to the ground.
During this descent, the shoulders begin to extend back towards the anatomical position. This action continues through the landing. As the subject lands, the ankles begin to dorsi-flex. During the dorsi-flexion, the knees and hips flex slightly to absorb the force of landing. By the end of the landing, the hip and knees are flexed, the shoulders are completely extended, and the feet are firmly planted on the ground. The hip joint flexes primarily due to the iliopsoas muscle. The knee is controlled by rectus femoris and biceps femoris muscles. R. emoris is responsible for extension and B. femoris is responsible for flexion. The ankle dorsiflexes because of the gastrocnemius and plantar flexes due to anterior tibialis. Shoulder flexion occurs because of Pectoralis major and extension occurs because of Latissimus dorsi. Biceps brachii is responsible for elbow flexion and triceps brachii is responsible for elbow extension. Flexor carpi radialis and Flexor carpi ulnaris are responsible for wrist flexion and Extensor carpi radialis and Extensor carpi ulnaris are responsible for the extension of the wrist.