Although baseball pitchers are renowned for their frequent disabling elbow and shoulder joint injuries, proper form to prevent these injuries demands that you use most of the moveable joints in your body. The overhand baseball throw can be divided into five basic groups of movements: the wind up, early cocking, late cocking, acceleration and follow-through.
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The baseball is gripped in your throwing hand, and this is covered by your gloved hand. Both elbows are bent, your spine is slightly curled, your shoulders are tipped, one leg is curled and held high with a bent knee, the weight-bearing leg is slightly bent, and the neck is cocked so you can look at where you are aiming the ball.
The pitcher lunges and transfers weight to the other leg. The hips and shoulders are wide, the spine is uncurled, the gloved hand moves with bent elbow across the abdomen, the throwing arm is raised with the ball strongly gripped, the wrist is flexed back, and the elbow is held at least as high as the shoulder and is bent to a 90-degree angle.
Mid-lunge, both knees are bent as the weight is fully transferred to the second leg. The hips rotate to face the aimed direction and carry with them the spine and shoulders. The gloved hand's arm is slightly bent to rest the glove at the front of the hip, the throwing arm is rotated at the shoulder to bring the elbow close to the head, the wrist begins to straighten, and the spine begins to bend forward to move the shoulders more forward than the hips.
The leg is being raised behind, both knees are bent, the spine is slightly curling to push the shoulders more forward than the hips, the throwing arm moves forward, and the elbow undergoes valgus stress as it extends. The wrist straightens and the ball is released by the fingers and thumb.
Also known as deceleration, the throwing arm shoulder rotates externally 50-degrees and the arm is brought across the torso and the spine curls and rotates to dip the shoulders forward to the non-throwing side. The first leg is curled and raised, and the weight-bearing leg is bent.
Joints Used in Proper Form
The joints you use to properly throw a baseball include those in your fingers and thumb, wrist (radius-ulna and carpals), elbows, shoulders, spine (vertebral arches and bodies), hips, knees (femur, tibia and patella), ankles (tibia-fibula and talus), and feet and toes. All in all, you use many joints in the body, and any of these may become injured at some point in the process of throwing. Use proper form and warm up properly before throwing a baseball.