A grade 2 AC joint separation is a kind of injury that some weightlifters think can be caused by the bench press.

Do not equate an “injured” AC joint with an actual separation.

Can bench pressing lead to an AC joint separation?

In an AC joint separation, the key word is separation. The ligaments are torn away from the bone, no longer attaching one part of the bone to the other.

An injury can occur to the AC joint without the ligaments tearing away from the bone.

In a grade 2 AC joint separation, the ligaments are severed, leaving the acromioclavicular joint in two pieces.

“Most likely, it is not directly from weightlifting,” says John-Paul H. Rue, MD, orthopedic sports medicine surgeon with Orthopedics and Joint Replacement at Mercy Medical Center in Baltimore, MD.

Even a heavy fierce bench pressing set won’t sever the AC joint.

“While the AC joint does see significant stress with some weightlifting activities, such as bench press or overhead press, these do not generally cause a grade 2 separation,” explains Dr. Rue.

“An AC separation usually results from a direct blow onto the point or top of the shoulder, such as with being driven to the ground in a tackle or falling off a bike or horse.

“Bench press or overhead press can cause distal clavicle osteolysis, which can lead to arthritis of the AC joint, due to overloading of the joint from repetitive stress caused by such lifting.”

So why do some men believe their bench pressing caused a grade 2 AC separation?

An X-ray will confirm this injury. However, in the absence of an X-ray, it might be suspected based on symptoms and maybe even appearance.

The patient might have a recent history of a fall onto the shoulder but it not considering that as the cause of his problem.

A patient might hear, “Looks like you might have a grade 2 AC separation,” even though there was no X-ray to show this.

A patient might also google their symptoms and conclude on their own that they not only have a genuine grade 2 AC joint separation, but that their recent round of intense bench pressing caused it.

What is distal clavicle osteolysis?

This is destruction of the outer end of the clavicle bone. It’s not the same as a joint separation and doesn’t even involve the ligaments.

Unless the barbell you’re bench pressing somehow falls out of your hands and slams into the outer area of your shoulder—in which case the injury would be caused by blunt force from a heavy object—the actual movement of the bench press cannot sever the ligaments in the AC joint.

Dr. Rue specializes in prevention and treatment of sports and exercise injuries. His primary focuses are knee, shoulder and elbow injuries including ACL and cartilage injuries, rotator cuff injuries and overuse tendonitis.
Lorra Garrick is a former personal trainer certified through the American Council on Exercise. At Bally Total Fitness she trained women and men of all ages for fat loss, muscle building, fitness and improved health.