ACSM Personal Trainer Certification Practice Exam

The primary benefit of shoulder internal rotation exercises is to strengthen which muscle?

1. Deltoid

2. Supraspinatus

3. Subscapularis

4. Triceps

The correct answer is: Subscapularis

The primary benefit of shoulder internal rotation exercises is to strengthen the subscapularis muscle. The subscapularis is one of the four rotator cuff muscles and plays a crucial role in shoulder stability and movement. It is located on the anterior (front) aspect of the scapula and is responsible for internal rotation of the humerus. Engaging in exercises that promote internal rotation specifically targets this muscle, which contributes to overall shoulder function and helps prevent injuries. In contrast, while the deltoid is involved in various shoulder movements, its primary function is shoulder abduction and flexion rather than internal rotation. The supraspinatus is primarily responsible for initiating shoulder abduction and stabilizing the shoulder joint, and the triceps primarily facilitate elbow extension and do not play a direct role in shoulder internal rotation. Therefore, the focus on internal rotation exercises directly benefits the subscapularis, reinforcing its importance in shoulder health and function.