How to strengthen the infraspinatus muscle
The infraspinatus is one of four muscles we call the rotator cuff at the shoulder joint. The rotator cuff muscles stabilise the shoulder joint, by keeping your arm bone within the shallow shoulder joint. It runs from the inside edge of your shoulder blade across to the top of your arm bone. The main action of the infraspinatus is to turn your arm out to the side. Here is an exercise to help strengthen the infraspinatus.