In throwing, which muscles are cited for acceleration by professional pitchers?

• A. Subscapularis and Latissimus Dorsi
• B. Rotator Cuff Muscles
• C. Pectoralis Minor
• D. Latissimus Dorsi Alone

Answer: (A)

During the acceleration phase of throwing, the arm is driven forward mainly by internal rotation and extension produced by the subscapularis and the latissimus dorsi. The subscapularis sits on the front of the shoulder and acts as a primary internal rotator, while the latissimus dorsi is a large muscle that extends, adducts, and internally rotates the arm. Together, they provide the strongest power to whip the arm forward and accelerate the ball to high speed. The rotator cuff muscles as a group primarily stabilize the shoulder and control movement, not generate the main accelerating force. Pectoralis minor helps position the scapula rather than produce the major acceleration. Thus, the combination of subscapularis and latissimus dorsi best explains the acceleration mechanism cited for professional pitchers.