The infraspinatus is a muscle located on the upper back, part of a group of muscles known as the rotator cuff. The rotator cuff is crucial for shoulder movements and stability. Specifically, the infraspinatus is situated on the shoulder blade and extends to the upper arm. Its main role is to help rotate the arm outward (external rotation) and stabilize the shoulder joint during various arm movements.
This muscle starts from the infraspinous fossa — which is a shallow cavity on the back of the shoulder blade — and attaches to the humerus, which is the long bone in the upper arm. When the infraspinatus contracts, it pulls on the humerus, allowing the arm to rotate away from the body. This is particularly important for actions such as throwing a ball or reaching behind your back.
Strengthening the infraspinatus is important not just for athletes who perform a lot of overhead and throwing motions, but also for everyday tasks that require arm movement. Weakness or injury in the infraspinatus can lead to shoulder pain and limited mobility, making it harder to perform basic activities that involve lifting your arm.
Exercises that focus on the rotation of the arm, especially those that encourage moving the arm away from the body while keeping the elbow close to your side, are effective in strengthening this muscle. Common exercises include external rotation with a dumbbell or a resistance band. These exercises can also help prevent injuries to the rotator cuff by improving the strength and stability of the shoulder joint.
Care should be taken not to overload the muscle, especially in the beginning stages of exercise, as this can lead to strain or injury. Starting with light weights or low resistance and gradually increasing the intensity is a safe and effective approach to strengthening the infraspinatus and improving shoulder function.