When you purchase through links in our articles, Future and its distribution partners may earn a commission.

Tense shoulders? Increase their mobility with this bodyweight arm exercise. All you need is an exercise mat – I love using the best yoga mats for at-home workouts – and a few minutes to spare.

Properly preparing your arms for upper body bodyweight exercises or weightlifting is crucial to optimal shoulder performance and health. Your shoulders have the greatest range of motion of all joints because they can help rotate your arms and raise them forward, backward, and sideways. However, they are also susceptible to injury, and if neglected, they easily become tight and weak.

Are you looking to add a new shoulder mobility exercise to your exercise program? Here is one of my favorites, as well as the benefits and how to do it.

What is shoulder internal rotation exercise?

Internal rotation means the rotation of a limb toward the midline or center of the body. The forearm will come closer to the body. The side-lying internal rotation stretch, also called the “sleeping stretch,” trains proper shoulder internal rotation and can improve shoulder internal rotation, which is important for overall range of motion.

Think of exercises like the barbell snatch, which require this type of arm and shoulder positioning.

You may have been told that external rotation is most important for good posture and optimal shoulder and back health; after all, your shoulders spend more time in internal rotation if you sit for long periods of time or if you have a habit of slouching and slouching.

However, it is important to train your shoulders in both external and internal rotation to ensure the best shoulder health. For example, internal rotation shoulder mobility will help you keep the bar close to you during technical lifting exercises such as weightlifting, so anyone who enjoys lifting weights – such as a CrossFitter – can benefit from these types of mobility exercises.

How to perform the shoulder internal rotation exercise while lying on your side

I like to counteract the external rotation stretch by pressing down on my hand to guide the back of my hand toward the mat, as shown in the video above. If you decide to do this, also hold for 30 seconds.

• Lie on your left side and extend your left arm in front of you on the mat

• Bend your elbow to create a 90-degree angle

• Place your right hand on the back of your left hand and then gently guide your left hand towards the mat

• Hold the stretch for 30 seconds or longer, then release

• Repeat for a few rounds, then switch sides.

What causes poor shoulder internal rotation?

There are many reasons why you may experience tight shoulders or lack of range of motion – overuse, repetitive movements, injuries or poor posture are just a few. Since the shoulders technically get the most movement from their joints, it’s best to exercise them in all planes of motion to keep them strong and healthy.

This means incorporating a variety of exercises that work your arms in different ways. I like to use adduction, abduction, frontal, lateral, inverse, and rotational movements during my upper body exercises to make sure I tick as many boxes as possible.

How to improve shoulder internal rotation

The main muscles responsible for internal rotation are the subscapularis (the part of the rotator cuff located around the shoulder blades), the pectoralis major, the latissimus dorsi, the teres major, and the anterior deltoid.

The best solution will be to add stretches and exercises that will bring the shoulder into internal rotation, and also focus on the muscles above, and the internal rotation stretch while lying on the side is one of my favorites.

What is the rotator cuff used for?

The rotator cuff surrounds the shoulder joints, helping to stabilize the shoulders and arms by resting around the shoulder blades, collectively known as the scapulae.

You have four main muscles that aid movement, including shoulder rotation (internal and external) and abduction, and also help perform a variety of functions – supraspinatus (rotation and abduction), subscapularis (internal rotator), infraspinatus (external rotator) and teres minor (external rotator).

Do you need shoulder internal rotation training?

It is important to exercise the shoulder in all directions to strengthen all muscle groups, including the rotator cuff. Building rounded shoulders helps improve mobility, stability and available range, also helping to improve exercise efficiency and the quality of movement patterns. Additionally, strong and mobile arms are less susceptible to injury.

As examples, I swear by these 5 shoulder stretches for relieving pain and increasing strength, and when my pecs feel tight, this one-minute stretch opens my shoulders and builds upper body flexibility.

More from Tom’s Guide