The scapula on your throwing shoulder upward rotates with the use of the middle/lower fibers of your trapezius muscles. The scapula on your glove hand shoulder protracts using the pectoralis minor and serratus anterior muscles.
Throwing Hand- Slight diagonal abduction of the shoulder joint by eccentrically contracting your posterior deltoid, infraspinatus, and teres minor muscles.
Glove Hand- Shoulder joint stays adducted by eccentrically contracting your latissimus dorsi, teres major, and lower pectoralis major muscles.
Glove hand elbow is slightly pronated by isometrically contracting your brachioradialis, pronator teres, and pronator quadratus muscles. Throwing elbow is flexed to about 30
Both hip joints remain in a slightly flexed position by concentrically contracting your iliacus, psoas major and minor, rectus femoris, sartorius, pectineus, and tensor fasciae latae muscles, causing an anterior pelvic tilt.
Both knees remain flexed by concetrically contracting your biceps femoris, popliteus, semimembranosus and semitendinosus.