Shoulder discomfort is common in resistance training, especially during pressing exercises. A frequent source of this pain is the Acromioclavicular (AC) joint, a small articulation near the top of the shoulder where the outer end of the collarbone (clavicle) meets the acromion of the shoulder blade. Pain in this area during movements like the bench press signals that the joint is being overloaded or stressed beyond its capacity.
The Anatomy of AC Joint Pain
The AC joint connects the axial skeleton and the shoulder girdle, allowing the scapula to move during arm elevation. It is stabilized by several ligaments, most notably the acromioclavicular ligaments and the stronger coracoclavicular ligaments, which anchor the collarbone to the coracoid process of the shoulder blade. These structures control the gliding and rotation that occurs when the arm moves.
During a deep bench press, the arm moves into horizontal adduction. This movement creates significant compressive or shearing force on the AC joint, especially under heavy load. The stress concentrates at the joint surfaces, leading to irritation of the cartilage and surrounding tissues. Repetitive strain from training can eventually compromise the integrity of the joint and its ligaments.
Common Diagnoses for AC Joint Pain
Several specific medical conditions are often responsible when shoulder pain is aggravated by the bench press. An acute injury, such as falling directly onto the shoulder, can cause an AC joint sprain or separation. These injuries are graded based on ligamentous damage, ranging from a mild stretch (Grade I) to a complete tear with noticeable joint displacement (Grades II and III).
Osteolysis of the Distal Clavicle (ODC), often called “Weightlifter’s Shoulder,” is a chronic overuse condition seen in heavy lifters. This pathology involves the gradual breakdown (resorption) of bone at the far end of the collarbone. The repetitive microtrauma and high compressive forces from years of intense pressing are thought to stimulate this degenerative process. ODC presents as pain localized directly over the joint that worsens with pressing movements.
Another potential cause is AC joint osteoarthritis, which involves the progressive wear and tear of the cartilage within the joint space. The frequent and heavy loading associated with resistance training can accelerate this degenerative change. This condition is characterized by pain and occasional clicking or grinding sensations during movements that compress the joint.
Immediate Steps and Conservative Treatment
Addressing AC joint pain starts with immediate activity modification. This involves temporarily resting from painful movements, such as the bench press and deep dips, to allow inflammation to subside. Applying ice to the affected area for 10 to 15 minutes several times a day helps manage localized swelling and discomfort. Non-steroidal anti-inflammatory drugs (NSAIDs) may also be used to reduce pain and inflammation.
If pain persists, seek professional guidance from a physical therapist or sports medicine physician. Conservative treatment focuses on restoring the stability and function of the shoulder complex. Physical therapy often targets strengthening the rotator cuff muscles and the scapular stabilizers, which help control the position of the shoulder blade during pressing and reduce mechanical stress on the AC joint.
If conservative management fails, a medical professional may recommend a corticosteroid injection. This procedure delivers a strong anti-inflammatory medication directly into the joint space to reduce inflammation and pain symptoms. Before returning to heavy lifting, a clear diagnosis and structured rehabilitation plan are necessary to prevent recurrence and ensure sufficient healing.
Modifying the Bench Press for Relief
Adjusting the bench press technique is often necessary to continue training while protecting the healing AC joint. One effective modification is using a slightly wider grip on the barbell, which reduces the amount of horizontal adduction required at the bottom of the lift. This limits the direct compression on the AC joint.
Limiting the range of motion is another practical adjustment that significantly reduces joint stress. Performing a floor press (where the elbows stop on the ground) or utilizing a board press (which places a physical barrier on the chest) prevents the bar from descending into the most painful position. This shallow range of motion avoids the end-range joint compression that aggravates AC joint issues.
A slight tucking of the elbows (maintaining an angle of about 45 to 60 degrees relative to the torso) shifts mechanical load away from the shoulder joint. This positioning encourages greater engagement of the pectorals and triceps, reducing direct strain on the AC joint. Also, reducing the overall training load by using lighter weights for higher repetitions decreases the force transmitted through the joint during recovery.