Shoulder Stabilization: what it is and why it matters by Paul Kevin Smith
As with all our major joints, the shoulders are supported by both deep muscles (the rotator cuff muscles), and more superficial muscles (the latissimus dorsi, the trapezius, the rhomboids, the serratus anterior, the deltoid, the pectoralis major and pectoralis minor). The rotator cuff is made up of four small muscles that connect the shoulder blade (scapula) to the upper arm bone (humerus): the scapularis, infraspinatus, supraspinatus, and teres minor muscles. The rotator cuff muscles help to keep the head of the humerus in the glenoid cavity (socket of the shoulder joint) during various movements, particularly abduction (pulling the arm toward the body). They are also utilized for fine-tuned movements of the upper arm involving abduction, external rotation and/or internal rotation.
For the best shoulder strength and stability, it’s important to exercise control in both exertion and relaxation. We should strengthen the superficial and deep muscles, and also train the deep muscles to relax when they are not needed (as when resting the arm on the armrest of a chair). The deep (rotator cuff) muscles must remain in a state of partial contraction most of the time to support the weight of the arms.
In actions such as push-ups, where great force is being exerted by the arms, it’s important to keep the shoulder blades fixed in place and tight against the back of the ribcage. This is accomplished by simultaneously contracting the middle trapezius (which pulls the shoulder blades toward the spine) and the serratus anterior muscles (which pull the shoulder blades toward the lateral ribs). This stabilization of the shoulder blades makes a good base of support for the arms to exert or absorb force.
Try it out
Here is a test for your shoulder blade stability: come into a plank position on hands and knees; notice whether the chest sinks, with the shoulder blades visibly pulling away from the back of the ribcage. This is called “winging”, and it’s a sign of weakness and/or lack of engagement of the middle trapezius and serratus anterior muscles.
The rotator cuff muscles can become fatigued and at risk of injury if they are utilized to fix the shoulder blades in place (instead of the using the middle trapezius and serratus anterior muscles for that job).
The following exercises can help us strengthen and appropriately engage the middle trapezius and serratus anterior muscles, so that they can better stabilize the shoulder joints. They could be performed 3-7 times per week for best effect:
- Anterior muscles:
Start at the top of a knee push-up position. Feel all the muscles around the shoulder joints contracting, especially at the front of the joints (pectoralis major and minor, and anterior deltoid).
Grip the floor with the toes and lift the knees off the ground to come into a full plank. Then lift one foot a few inches off the ground, and alternate shifting most of your weight into the right hand, pausing for a second or two, and then into the left hand.
As you shift weight from side to side, continue to feel strong in the muscles at the front of the shoulder joints, not allowing the chest to collapse toward the floor, or the shoulder blades to wing away from the back of the ribcage.
Perform 10 repetitions of shifting to each side alternately.
- Serratus anterior muscles:
From a hands and knees position, slightly flex (arch or round) the thoracic spine (middle to upper back), feeling the shoulder blades moving apart slightly, with their inner edges flattening against the back of the ribcage.
Maintaining the slightly flexed thoracic spine, repeat the movements of exercise #1:
Grip the floor with the toes and lift the knees off the ground to come into a full plank. Then lift one foot a few inches off the ground, and alternate shifting most of your weight into the right hand, pausing second or two, and then into the left hand.
As you shift weight from side to side, continue to feel slightly flexed in the thoracic spine, not allowing the chest to collapse toward the floor, or the shoulder blades to wing away from the back of the ribcage.
Perform 10 repetitions of shifting to each side alternately.
- Posterior muscles:
From sitting with the legs outstretched in front, come to a reverse plank position, with hands underneath and slightly wider than the shoulder joints, and the fingers pointed outwards. If comfortable to do so, keep the head and neck in line with the spine, looking forward and up. If that is not comfortable for the neck, then tuck the chin and look towards the feet.
Hold the reverse plank for 30 seconds. Focus on feeling contraction of the posterior shoulder muscles: the rhomboids, trapezius, and posterior deltoids, and also the triceps muscles at the back of the upper arms.
When we know how to engage the muscles that best support the shoulder blades, we will be at lower risk of injuring the rotator cuff muscles when doing strength training and calisthenics exercises.
Paul Kevin Smith has a M.Ed. degree in Kinesiology from U.T. Austin, and is a Level 2 certified provider of the Functional Movement Screen. His other certifications include ACSM Clinical Exercise Physiologist, ACE Health and Wellness Coach, PhysicalMind Institute Pilates Mat Work Instructor, Experienced Registered Yoga Teacher (500 hours), and IAYT Yoga Therapist. Paul is an Adjunct Professor of Exercise Science and Student Development at Austin Community College, and also teaches yoga and Pilates classes and leads personal training sessions at BodyBusiness Fitness Club.
Paul can be reached at 512-731-7167, [email protected], Instagram @pksmithatx, and online at http://www.paulkevinsmith.com.
Paul offers Functional Movement Screens at CrossFit Renew. In this session he analyzes your mobility and stability in performance of ten movements. You will receive a report detailing your results, and a personalized exercise program to improve your functional performance. 60 minute session: $75.
