The acromioclavicular (AC) joint connects the collarbone (clavicle) to the highest part of the shoulder blade (acromion). Injuries to this joint, often called a separated shoulder, involve damage to the supporting ligaments and require a methodical, phased approach to rehabilitation. This article offers a structured guide to exercises that align with the body’s natural healing progression, moving from gentle movement to restoring full strength.
How Injury Severity Impacts Rehabilitation
Recovery is determined by the severity of the AC joint sprain, which is commonly graded on a three-point scale based on the degree of ligament damage. A Grade I injury involves a minor sprain with minimal displacement of the joint, and the rehabilitation timeline is typically the shortest. For this grade, gentle movement exercises may begin within a few days of the injury to prevent stiffness and promote early healing.
A Grade II injury indicates a tear of the acromioclavicular ligament and a partial tear of the stronger coracoclavicular ligaments, resulting in a noticeable step deformity. This increased ligament damage requires more caution, and initial movement may be delayed for 7 to 14 days to allow for initial soft tissue healing. Grade III injuries involve a complete tear of both ligament sets and significant joint displacement, often requiring a longer period of immobilization and surgical consultation before aggressive physical therapy is considered. The rehabilitation approach for all grades emphasizes protecting the joint while progressing through range of motion and strength phases based on clinical milestones.
Gentle Exercises for the Initial Recovery Phase
The earliest phase of rehabilitation focuses on pain management and preventing the shoulder from freezing up. These initial movements are performed passively or with minimal effort to encourage blood flow and maintain joint lubrication without stressing the damaged ligaments. The goal is to move the arm below the level of pain, ensuring the exercise itself does not provoke a sharp or shooting sensation.
A starting point is the Pendulum Swing, performed by leaning forward and allowing the injured arm to hang loosely toward the floor. The patient initiates small, gentle circles in both clockwise and counterclockwise directions, using body sway rather than shoulder muscle contraction to move the arm. This technique provides low-impact motion that facilitates circulation.
The Finger Walk uses the fingers to “walk” the hand up a wall, stopping immediately when discomfort is felt. This controlled movement allows the patient to explore their pain-free limit for shoulder elevation without lifting the full weight of the arm. For passive range of motion, the non-injured arm can gently support and move the injured arm through flexion and rotation, such as using a dowel rod to push the arm slightly forward and outward.
Regaining Full Shoulder Mobility
Once the acute pain subsides and the joint can tolerate some active movement, the focus shifts to restoring the full, active range of motion. These exercises require the patient to actively use the muscles surrounding the shoulder to move the joint, preparing the tissues for later resistance work. Wall Slides are a good way to improve elevation, where the patient slides their hands up a wall in front of them, controlling the movement actively on the way up and down.
Doorway Stretches help address tightness in the anterior shoulder and chest muscles, which often become restricted after a period of immobilization. Standing in a doorway with forearms braced against the frame, the patient steps slightly forward to feel a gentle stretch across the front of the shoulder.
To restore rotational capacity, the patient can use a long stick or dowel rod to perform Assisted External and Internal Rotation, using the uninjured arm to guide the injured arm through its rotational limits. This transition phase is important because full mobility is a prerequisite for safely beginning strengthening exercises.
Building Strength and Joint Stability
Strength restoration is fundamental for stabilizing the AC joint and preventing future injury. The primary focus of this phase is strengthening the periscapular muscles—the muscles that control the shoulder blade—and the rotator cuff. These muscle groups act as dynamic stabilizers.
Scapular Squeezes are foundational exercises that can be performed without resistance initially, by squeezing the shoulder blades together and holding the contraction for a few seconds. These movements activate the mid-back muscles, which are responsible for keeping the shoulder blade in a stable position.
Introducing light resistance is done through exercises like Banded External Rotation, where the arm is rotated outward while the elbow remains tucked at the side using a resistance band. This targets the infraspinatus and teres minor, muscles important for cuff stability.
Isometric Contractions are also incorporated early in this phase, involving pushing against an immovable object like a wall or doorframe in various directions. They provide a safe way to introduce load and reinforce the surrounding musculature. As tolerance improves, exercises such as Light Resistance Band Rows can be introduced, focusing on pulling the band toward the body while maintaining proper scapular control. Resistance should always be low, starting with high repetitions to build endurance before attempting to increase the load.
Essential Safety Precautions and Movements to Skip
Protecting the healing joint requires a strict adherence to safety guidelines, particularly concerning movements that can provoke pain or place excessive stress on the AC joint. Horizontal Adduction, which involves bringing the arm across the front of the body, should be avoided as it compresses the AC joint.
Activities that involve heavy Overhead Pressing or lifting, such as military presses or wide-grip bench presses, should be postponed for at least 6 to 12 weeks, as they place a high amount of shear force on the joint. Any exercise that causes a sharp, shooting pain, clicking, or grinding sensation should be immediately stopped and reviewed with a medical professional.
Movements that involve reaching behind the back for internal rotation, especially when combined with extension, can also stretch the joint capsule and should be avoided. The return to high-impact activities like contact sports or heavy weightlifting must be gradual, ensuring that full, pain-free range of motion and near-normal strength levels are achieved before clearance is given.