Don’t miss the first article in this series:
Improving Body Awareness: Understanding the pelvic floor muscles—and 3 exercises to activate this area >
What is the rotator cuff?
The rotator cuff is made up of four muscles: the supraspinatus, infraspinatus, teres minor and subscapularis. You can remember these muscles by the acronym S.I.T.S.
These four muscles collectively help stabilize the glenohumeral joint, which is part of the shoulder girdle. The shoulder girdle is comprised of three bones: the humerus, scapula and clavicle, and a series of joints including the acromioclavicular, glenohumeral and scapulothoracic (not a true joint). The glenohumeral joint is one of the most mobile joints in the body and when combined with the movement of the scapula provides a huge range of motion for the arm and hand.
The rotator cuff muscles are deep stabilizers, located closest to the bones of the glenohumeral or shoulder joint. They each attach to the scapula then surround the head of the humerus like a cuff, hence their name.
What do the rotator cuff muscles do?
Although the rotator cuff muscles contribute to movements including abduction, internal and external rotation, they are only synergists to those movements. Their role is to assist the larger, more superficial muscles like the latissimus dorsi, pectoralis major and deltoids, often initiating the movement before the larger muscles kick in. They are often neglected when training because the primary muscles take over the action.
In an area like the shoulder joint that has so much mobility, you need to counterbalance it with stability. The rotator cuff muscles are a great place to start, although there are many other muscles that will contribute to stabilizing this area. The primary role of the rotator cuff is to maintain the approximation of the glenohumeral joint by acting like a suction cup, keeping the head of the humerus pulled in to the fossa, not allowing the larger muscles to pull it away.
Why is the rotator cuff easily injured?
Since these small deep muscles are somewhat forgotten, they are often injured. When there is greater pull from the mobilizing muscles than the smaller rotator cuff muscles can manage, damage occurs. The large range of motion available due to the form closure of the joint, and the need for even more force closure (stabilizing muscle activation), provide good reason to focus on low load activation in order to prevent injury.
It is also important to note that stabilization of the glenohumeral joint by the rotator cuff should be accompanied by appropriate stabilization of the scapulae. It is important that you do not over stabilize and/or try to hold the scapulae still against the rib cage. They are meant to glide and move in synchrony with the movement of the arm and shoulder.
How should an instructor cue their client when working the rotator cuff?
As local stabilizers, the rotator cuff muscles respond best to exercises done with low loads, small ranges of motion and shorter levers. Starting in a good neutral position of both the glenohumeral joint and the scapula will ensure that the exercises performed are targeting the correct muscles.
- Think of holding a book between your arm and your side. The goal is to keep your arm still in space to achieve adequate rotation. This could work when cueing either internal or external rotation
- If you see a client winging in the scapula, try using a cue such as: “Suction cup your scapula to your rib cage” or “imagine a row of green peas underneath your medial border and try to squish the green peas”
- If the wrist is breaking or not maintaining neutral alignment, cue them to “imagine a cast on the wrist” to keep it straight
- If you see the head of the humerus rolling forward, tell them to think of the front of the chest like wings, spreading out to the sides of the room
- Instructors should emphasize neutral alignment through all curves of the spine, particularly the thoracic, to help the scapula sit flush on the ribs
3 rotator cuff exercises to try with your clients
In each case, remember that the resistance should be fairly light to ensure the proper muscles are executing the movement.
Watch the video above or follow the instructions below:
1. Internal rotation (to target subscapularis): Attach a Flex-Band® to something solid, then stand, kneel or sit and hold it in the closest hand. Neutral pelvis and spine, as well as the scapula and shoulder joint. Inhale to prepare; exhale to rotate the arm internally; inhale to return.
2. External rotation (to target teres minor and infraspinatus): Attach a Flex-Band to something solid, then stand, kneel or sit and hold the band in the hand that’s furthest away. Neutral pelvis and spine, as well as the scapula and shoulder joint. Inhale to prepare; exhale to externally rotate the arm; inhale to return.
3. Abduction long arm (to target supraspinatus): Place a Flex-Band under the knees and hold it in one hand. Kneeling, in neutral pelvis and spine. Inhale to prepare; exhale to abduct the arm away from the body. Note, you can do this with a shorter lever to decrease the load. This will help if your client lacks strength and stabilization, if they have an injury, or to decrease the contribution of the larger muscles. You could also do this with a light dumbbell rather than a Flex-Band.
Additional ways to intensify or modify rotator cuff exercises
Place a small ball under the arm if the client is having difficulty maintaining stability in the shoulder girdle.
Intensify the challenge for the rotating muscles by adding in shoulder extension.