Shoulder impingement, or subacromial impingement, is a common source of shoulder pain. This condition occurs when the tendons of the rotator cuff, particularly the supraspinatus, become pinched or irritated as they pass through the narrow subacromial space. This space sits directly beneath the acromion, the bony arch at the top of the shoulder blade. The resulting irritation causes pain, weakness, and restricted movement.
The Core Principle: Avoiding Shoulder Compression
The fundamental rule for managing an impinged shoulder is to avoid any movement that mechanically narrows the subacromial space. This narrowing occurs when the arm is lifted away from the body, causing the humeral head (upper arm bone) to press upward into the acromion. Any activity that forces the rotator cuff tendons against the bone under load will increase friction and inflammation. This pinching sensation is most often experienced within the “painful arc” of movement, typically when the arm is lifted out to the side between 70 and 120 degrees. Moving the arm above shoulder height or across the body, especially with resistance, creates a direct compressive force on the tendons and bursa.
High-Risk Weightlifting and Resistance Training Exercises
Heavy overhead movements are a primary concern, as pressing a barbell or dumbbells directly overhead forces the humeral head to translate superiorly, or upward, directly into the acromion. This action severely limits the subacromial space, pinching the supraspinatus tendon and bursa.
The Upright Row is another widely recognized problem exercise because it forces a biomechanically unsound position. During this lift, the arm is simultaneously elevated and internally rotated. This internal rotation drives the greater tuberosity—a bony crest on the upper arm bone—directly into the acromion, causing a collision that irritates the underlying soft tissue.
Behind-the-neck movements, such as Lat Pulldowns or Military Presses performed to the back of the head, subject the shoulder to extreme positions of external rotation and horizontal abduction. This motion applies significant shear and compressive forces to the rotator cuff, leading to irritation and inflammation. Similarly, exercises like deep chest dips or push-ups that allow the shoulder to drop excessively below the neutral plane can over-stretch the anterior capsule and strain the irritated tendons.
The Lateral Raise, while not fully overhead, can still be problematic if performed with heavy weight or poor form, as the painful arc is often encountered within the lifting range. Avoiding these high-risk movements altogether is often the best strategy during initial recovery.
Common Daily Activities That Aggravate Impingement
Shoulder impingement pain is frequently aggravated by everyday movements. Reaching overhead to access a cupboard or place dishes on a high shelf causes the same narrowing of the subacromial space as a military press, leading to an immediate flare-up of symptoms. Repetitive or sustained overhead tasks, such as painting a ceiling or washing a car, are irritating because they prolong the compression.
Reaching behind the back, a motion requiring internal rotation and extension, is also a common trigger for pain. Simple actions like fastening a bra, tucking in a shirt, or reaching for a seatbelt can compress the tendons at the rear of the joint. Carrying heavy objects, such as luggage or grocery bags, away from the body places strain on the shoulder by requiring the rotator cuff to stabilize a load with poor leverage.
Sleeping position is another major factor, as the pain often intensifies at night. Lying directly on the affected shoulder can compress the joint for hours, causing morning stiffness and pain. Sleeping with the arm in an overhead position can similarly compress the subacromial structures, prolonging the inflammatory cycle.
Safe Movement Principles and Alternatives
The goal of safe movement is to strengthen the shoulder girdle without compressing the rotator cuff tendons. The focus shifts to improving the coordinated movement between the arm and the shoulder blade, known as scapulohumeral rhythm. Strengthening the muscles that stabilize the shoulder blade, particularly the lower trapezius and serratus anterior, is foundational for creating more space for the arm bone to move.
Generally, all exercises should be performed within a pain-free range of motion, which frequently means keeping the arm below 90 degrees of abduction. Safe alternatives often involve external rotation exercises performed with a light resistance band, keeping the elbow tucked tightly to the side. This targets the rotator cuff muscles directly without significant joint compression.
Scapular retraction exercises, such as seated or standing resistance band rows, are beneficial because they strengthen the mid-back muscles responsible for pulling the shoulder blades together and back. Movements like wall slides or gentle pendulum swings can help maintain mobility by supporting the arm or removing the need for active muscle contraction. These controlled, low-load exercises help rebalance the shoulder’s mechanics, encouraging the joint to move properly and reducing the risk of recurrence.