Shoulder pain occurs in up to 21% of the general population. Shoulder impingement is the most common, accounting for 40 to 65% of reported shoulder pain, while shoulder dislocations account for an additional 15 to 25%. Shoulder pain may be the result of degenerative changes to the shoulder’s capsuloligamentous structures, articular cartilage, and tendons as the result of altered shoulder mechanics. Degenerative changes may also affect the rotator cuff by weakening the tendons with time through movements such as repetitive overhead use, increased loads raised above shoulder height, forward head and rounded shoulder posture, as well as altered scapular kinematics and muscle activity. Preventative exercise is key to avoid shoulder injuries.
The following can lead to shoulder injuries:
Static Malalignments (altered length-tension relationships or altered joint arthrokinematics)
Posterior glenohumeral capsular contracture causes restricted internal rotation of the shoulder and causes shoulder pain and potentially impinge the rotator cuff. Rounded shoulders also affect the length-tension relationship and joint kinematic balance of the shoulder complex.
Abnormal Muscle Activation Patterns (altered force-couple relationships)
Rounded shoulder posture lengthens the rhomboids and lower trapezius musculature and shortens the serratus anterior, which alters the normal scapulothoracic force-couple relationship. This altered posture and muscle recruitment pattern would cause the scapula to remain forward-tipped and internally rotated relative to the elevating humerus, forcing the acromion and humerus to approximate and narrow the subacromial space. Furthermore, a rounded shoulder posture may lead to decreased rotator cuff activation, which would decrease stabilization and lead to compression of the humeral head.
85% of the muscle activation required to slow the forward-moving arm while throwing comes from the core and the scapulothoracic stabilizers (trapezius, rhomboids, serratus anterior). Maximal rotator cuff activation can be increased by 23 to 24% if the scapula is stabilized by the core musculature and the scapulothoracic stabilizers. Altered static posture, muscle imbalances, and muscle weakness in the lower extremity, LPHC, or upper extremity can lead to dynamic malalignments.
3 Preventative Exercises
1. Shoulder External Rotations: Part 1
Benefits: This exercise isolates 2 of the 4 rotator cuff muscles, the Infraspinatus and Teres Minor. These two muscles are important specifically for positioning the head of the humerus posteriorly (backwards) in the joint socket.
How: Begin with your elbow and upper arm at 90 degrees and by your side. Hold a resistance cable or exercise band. Keep your elbow close to your body and slowly rotate your hand and forearm away from your body while keeping your elbow connected to your body (you can even put a small towel in between your elbow and side and make sure to not let it fall). Be sure not to arch your low back, dip a shoulder to one side or lean forward with your upper body. Hold for 1-2 seconds at the end range before slowly rotating your arm and hand back in.
2. Shoulder External Rotations: Part 2
Benefits: This is the next step up for increasing strength and neurological coordination of the Infraspinatus and Teres Minor. Since so many of our daily and athletic activities require our arms and shoulders to be elevated to and above shoulder height.
Caution: Stop or modify if you feel any pinching, uncomfortable clicking or pain and consult as personal trainer or physical therapist.
How: Begin with your upper arm parallel to the ground at shoulder height with the elbow flexed to 90 degrees. Hold a resistance cable or exercise band and begin with the forearm also parallel to the ground. While keeping your shoulder blades retracted and your elbow in line with or just in front of your shoulder, rotate your forearm backwards until it is perpindicular with the ground. Be sure not to arch your low back, dip a shoulder to one side or lean forward with your upper body. Hold for 1-2 seconds at the end range before slowly rotating your arm and hand back down.
3. Shoulder Retractions
Benefits: This exercise is great for improving posture by activating the upper back muscles that keep the spine upright and the shoulder blade muscles that keep the shoulder blades from collapsing forward and internally.
How: Keep your arms straight at all times throughout the entire exercise. Be sure not to let your head shift forward as the shoulder blades and arms move backwards. Also be sure not to hunch over or overarch the low back.
Squeeze the shoulder blades together (retraction) without shifting any other part of your body (head, neck, low back, elbows bending). Hold for 3 seconds and repeat 10-15 times.
Doing this exercise correctly is much harder than it looks!
If you need assistance, please reach out!
Sources: NASM CES 2014