Tuesday, October 5, 2010

Arm Acceleration

Phase 5- Arm Acceleration

The movement of bringing your arm forward from the late cocking position. This phase ends when the ball is released from your hand.

Shoulder Girdle
With your throwing shoulder, the scapula protracts using the serratus anterior muscle and pectoralis minor muscle. The scapula of your glove hand will maintain retraction using your rhomboid muscles and the middle/lower fibers of the trapezius muscle.

Shoulder Joint
Throwing Hand- Diagonally adducts shoulder joint by concentrically contracting your pectoralis major, anterior deltoid, and coracobrachialis muscles.
Glove Hand- Shoulder joint stays in adduction by eccentrically contracting your latissimus dorsi, teres major, and lower pectoralis major muscles.

Elbow Joint
Stays flexed to 10˚ with your glove hand elbow by concentrically contracting both heads of the biceps brachii, brachialis, and brachioradialis muscles. Your throwing hand forearm also stays slightly supinated by concentrically contracting both heads of the biceps brachii, brachioradialis, and supinator muscles.

Hip Joint
Your lead foot causes the hip to stay externally rotated by eccentrically contracting your piriformis, gemellus superior and inferior, obturator internus and externus, and quadratus femoris muscles. This causes a left transverse rotation. The opposite side of your hip stays internally rotated by concentrically contracting your gracilis, semitendinosus, and semimembranosus muscles causing a right transverse rotation pelvic tilt.

Knee Joint
Lead knee remains slightly flexed by concetrically contracting your biceps femoris, popliteus, semimembranosus and semitendinosus. The opposite knee remains internally rotated by isometrically contracting your popliteus, semimembranosus and semitendinosus muscles.

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