The AC (acromioclavicular) joint is where the collarbone and scapula meet. It can be damaged through a fall onto an extended arm or the point of the shoulder, as may occur in skiing or a bike accident. Dislocations and cartilage tears are possible. Pain from injury to the joint may be felt in the top of the shoulder, when moving your arm across your body or overhead. Following medical evaluation, rest is the first step to recovery. Once pain and swelling have passed, mobility work, flexibility and strength training will help keep the muscles toned and support the joint.
A movement called the pendulum is one example of exercise to increase mobility in the shoulder. The pendulum directly affects the AC joint. Assume a position similar to that used to perform a tricep kickback. Your knee (on the side with the damaged shoulder) should be forward and slightly bent, the other leg back and behind your body. The uninjured arm may support the body by resting on a stable surface.
Beginning with small arcs, swing the affected arm back and forth slowly along the side of your body. Repeat with a side to side motion, taking the arm across the front of your upper body. This exercise is very easy to do during breaks and on the trail.
Stretching is also important for recovery. Stretching can be used to increase mobility and work stiffness from the joint once the area is pain free. Extend your arm out from the side of your body, then bend the elbow to a 90-degree angle. Press the underside of your forearm against the frame of a doorway or against the trunk of a tree. Slowly turn your body away from your forearm to create a stretch in the front side of the shoulder and joint.
Do not attempt to stretch to the extreme limit of your range of motion. Instead, breathe deeply and hold the stretch, relaxing into the position and allowing your body to gradually release. Hold each stretch for 30 seconds and repeat several times per day.
Strengthening the Shoulder
Strengthen the muscles of the shoulder after an AC joint injury with range-of-motion exercises. These should begin with no resistance (only body weight) and then progress to light bands, then light hand weights to prevent re-injury or damage during healing.
Extend your straightened arm out in front of your body. Do not lock the elbow. Move your hand in an arc toward the opposite shoulder. Follow the same path as you return, but continue until your arm is fully extended to the side (parallel to the floor). If possible, repeat ten times, very slowly.
Next, return to the starting position and lift your (straightened) arm until it extends upward, directly over your shoulder. Lower your arm to your side and raise it overhead again in large arcs. If possible, repeat 10 times, very slowly. If you are outdoors or engaged in another activity, substitute a water bottle for a hand weight.
Article Written By Alice Moon
Alice Moon is a freelance writer with more than 10 years of experience. She was chosen as a Smithsonian Institute intern, working for the National Zoo in Washington, D.C., and has traveled throughout Asia. Moon holds a Bachelor of Science in political science from Ball State University.