What is the normal range of motion for internal and external rotation of the glenohumeral joint?

The normal range of motion for internal and external rotation of the glenohumeral joint is typically about 90 degrees for each movement. This range reflects the anatomical design and functional capabilities of the shoulder joint, which is a ball-and-socket joint allowing for a significant degree of movement.

Internal rotation involves moving the arm towards the body, while external rotation is the opposite motion, moving the arm away from the body. Having a range of around 90 degrees for each rotation ensures that individuals have the necessary mobility for various activities, such as reaching or throwing.

Understanding this range is crucial for personal trainers when designing exercise programs, as it helps ensure that exercises are safe and effective, preventing limitations in shoulder mobility that could lead to injury.