Impingement Syndrome


Impingement Syndrome

Early Diagnosis, Rehabilitation and Post-Rehabilitation Guidelines For Personal Trainers, Strength Professionals and Athletic Trainers

By Chris Gellert, M.P.T, C.S.C.S, C.P.T

The glenohumeral joint (shoulder) is a complex structure exhibiting the greatest amount of motion of any joint in the body. Making it most susceptible to injury and potentially requiring physical therapy. Delay in recognition and treatment can potentially result in surgical intervention.

One of the most common injuries seen in athletes as well as men is a shoulder pain dysfunction called impingement syndrome. Early diagnosis and recognition by a trained medical profession is vital. Most often an individual will see a rehabilitation specialist (i.e.. Physical Therapist) for treatment but what is even more essential, is post rehabilitative care as to prevent from reoccurrence or potentially surgery.

In this article, I will identify the anatomy-pathomechanics of the shoulder, mechanisms of injury/predisposition, rehabilitation as well as fundamental post rehabilitative guidelines that a personal trainer or strength and conditioning professional should follow.

Anatomy of the Shoulder

The subacromial space is formed by the acromion and coracromial ligament anterosuperior and the superior aspect of the humeral head inferiorly. From the figure below, you can see that the space is comprised of connective and soft tissues making it susceptible to injury. The rotator cuff is uniquely comprised of the following muscles; (supraspinatus, infraspinatus, teres minor and subscapularis). Each muscle performs a dynamic role to support and ultimately stabilize the shoulder girdle. This makes the shoulder vulnerable for any individual as well as the athletic population.

The supraspinatus assists the deltoid by abducting the shoulder, and the subscapularis internally rotates as the teres minor and infraspinatus externally rotates the shoulder.6

From Souza et al4

The rotator cuff functions to essentially maintain a force-couple relationship with the deltoid that secures the humeral head within the glenoid. When this relationship is compromised, the pull of the deltoid forces the humeral head proximally and the rotator cuff is compressed or impinged beneath the coracromial arch. 2 Researchers have studied the acromion shape. Bigliani studied the shape of the acromion in 140 cadavers to determine the relationship between full-thickness tears of the rotator cuff. Bigliani found that 70 percent of 50 patients with full-thickness tears had a hook acromion. Supporting the use of the acromioplasty procedure for impingement syndrome as an option.5

Mechanism of Injury-Theories

The source of impingement has been a controversial topic amongst physicians and the medical community for many years. Neer 4 speculated that the cause of impingement was a mechanical problem as a result of crowding amongst the anterior acromion. This came to be known as primary impingement. As a result of this theory, he developed and implemented the anterior acromioplasty, which involves removing of the anterior portion of the acromion. This provides adequate space for the inflamed tendons to glide 3. Another theory states that impingement is a result of instability and/or muscle weakness called secondary impingement.

Neer’s Classification of Impingement 5


Stage 1

Patient is <25 yo with a hx of repetitive lifting. Pt complains of dull ache after activity. S&S: Tenderness in the supraspinatus tendon, painful arc from 60-120 deg

Stage 2 25-40 yo individual, symptoms are worse the stage 1. More soft tissue crepitus and or a catching feeling. S&S: Simple overhead movement is painful.

Stage 3 Found in individuals >40 yo and have had pain for prolonged periods of time.
S&S: Present with more limitation in active and passive ROM, X-rays indicate degenerative or changes within GH joint.


Primary Impingement Syndrome (Structural)

Structural causes include acromial shape, narrowing due to inflammation, and capsular laxity. As the acromion has been identified as one structural cause, there is a relative decrease in the subacromial space caused by an instability of the glenohumeral joint. In other words, a mechanical dysfunction with abduction, the humerus impinges into the anterior acromion. As seen in the figure below.

Repetitive compression forces of the above structures against the anterior acromion and coracromial ligament combined with repetition causes swelling of the involved tendon, and lead to tendonitis. Particularly, the supraspinatus and the long head of the bicep tendon are those soft tissue structures involved. Swelling of an involved tendon narrows the available space for other occupying structures within the subacromial outlet.5 Individuals will experience pain with overhead lifting particularly past 90 degrees in the frontal plane as a result of the pressure on the inflamed tendons.

Secondary Impingement Syndrome (Functional)

Secondary impingement is caused typically by either weakness of the rotator cuff mechanism and the biceps tendon, leading to a overload within the glenohumeral joint, muscle imbalance and/or a tight posterior capsule.

The active restraints of the GH joint (bicep tendon/rotator cuff) attempt to stabilize the humeral head; however, they eventually fatigue and weaken. This results in the humeral head to mechanically impinge the rotator cuff tendon by the coracromial arch. 1

The most common observation of muscular imbalance seen in an individual with impingement syndrome, is a muscle imbalance between the external rotators and abductors and internal rotators and adductors.3 Posterior capsule tightness results in anterosuperior humeral head translation.


An individual usually complains of anterior deltoid discomfort described as “ache or deep pain,” as well as experience pain with lying on the affected shoulder, Diagnostic imaging (x-rays) usually are unremarkable and show no bony damage. MRI’s are another great diagnostic tool that can be used to visualize the integrity of the supraspinatus tendon and shoulder respectively.

Intact rotator cuff Complete rotator cuff tear

(Source: Esch, Baker CL Arthroscopic Surgery: The shoulder and Elbow Philadelphia, JB Lippincott, 1993:31)


The primary goal with treatment is to decrease inflammation and irritation within the subacromial space. Modalities such as electric stimulation and gentle range of motion exercises are initially used. Followed by gentle posterior capsule stretching and active strengthening.

When appropriate, strengthening is concentrated on the rotator cuff (external rotators and the scapular rotators to establish proper scapulohumeral rhyme). Rotator cuff strengthening decreases the impingement by improving humeral head depression and preventing further anterosuperior elevation of the humeral head during arm elevation. Scapular rotator strengthening provides the scapula to follow the humerus, providing both static and dynamic stability.

Post-Rehabilitative Treatment

Exercises to Avoid with Impingement Syndrome:

Behind the neck press exercise - This exercise requires that the shoulder start in a lateral and abducted position. The second component involves pulling the shoulder into retracted positioning (pinching the shoulder blades together), while maintaining an externally rotated position. This maneuver tends to lead to increased impingement, where the RTC becomes jammed under the anterosuperior surface of the acromion irritating the tendon and causing it to become inflamed.

Shoulder Press - Puts excessive stress/strain on the rotator cuff tendon and acromion.

Lateral Raises - This is commonly performed on a machine where the palm is faced down (IR of GH joint). During arm elevation, the greater tuberosity of the humerus pinches the rotator cuff tendon and bursa against the acromion. Repetitive pinching can lead to inflammation and damage to the rotator cuff.

Upright Row – This may lead to impingement. As the arm is raised up during motion/exercise, there is IR of the humerus causing crowding into the acromion, which through repetition causes irritation of the ac joint.

Exercises that involve excessive flexion (i.e.. Supine Pullover exercise)

Post-Physical Therapy Treatment:

Emphasis is to create scapular stability/balance the shoulder muscles dynamically Strengthening scapula retractors (rhomboids, low trapezius), depressors and protractors (Sarratus anterior) respectively.

Specific Training Approach for Trainer with Client - Begin with closed chain exercises, then emphasize strengthening Sarratus anterior, middle trap and low trapezius scapular stabilization exercises (supine PNF with tubing depresses scapula) to ER, gravity assisted then introducing Empty can Exercise (Supraspinatus last) and finally gravity based exercise and movement.

Recommended Exercises:

Scaption strengthening-Standing lateral raise-arms abducted with 30 degree anterior to the frontal plane.

Scaption exercise where there is a standing lateral raise-arms abducted with 30 degrees anterior to the frontal plane.

Scapular protraction/Low trapezius strengthening –together both cause an upward rotation of the scapula to maintain the subacromial space above 90 degrees of shoulder elevation. During the first 30 degrees of scapular rotation(0-90 deg of shoulder elevation), the upper trap and upper fibers of Sarratus anterior work together to upwardly rotate the scapula.

ER in neutral or at 90 degrees

Supine with the retubing-stabilizes the scapula

Posterior capsule stretching

Strengthening posterior shoulder - with emphasis on posterior deltoid, infraspinatus, ER's and scapular retractors (rhomboids, etc.), scapular depressors (low trapezius), scapular protractors (Sarratus anterior).

NOTE: Together the Sarratus anterior and low trapezius cause upward rotation of the scapula to maintain the subacromial space above 90 degrees of shoulder elevation.

Balance the shoulder muscularly with greater concern


The personal trainer, athletic trainer and strength professional are encountering more individuals post-rehabilitation, making the post-rehabilitative market an opportunity for everyone. Each professional plays a vital role in helping an individual reach his/her optimal function. It is vital that they clearly understand the pathology, restrictions and most importantly, communicate with the medical team regarding any uncertainty. In order to improve the gap between physical therapists and fitness professionals, each party needs to respect each other’s boundaries. In doing so, respect is earned, individuals reach optimal function and potential injury is avoided.

When in doubt about a particular exercise or program design with a certain injury, always consult with the appropriate healthcare provider (i.e. Physical Therapist).