Winged scapula is a common biomechanical deficiency which is caused by two things: short (tight) pectoralis minor and long (weak) serratus anterior/lower trapezius. In severe cases, it looks like a person's shoulder blades are poking up out his or her back. I saw one guy on the bike course at Lawrence 70.3 who made me cringe, his scapulae were so poky. But in a less severe case, the condition will show itself if you push hard against a wall with palms flat at waist level (not sure on the biomechanics of why this is the case, beyond the fact that this movement should use the serratus anterior and if they're weak it'll show up here). One of the other trainers at my gym did this once and completely grossed me out. He looked like a frickin' gargoyle.
So why should you care that your shoulder blades stick out like a pterodactyl's? First off, it destabilizes your shoulders. The shoulder is a pretty intricate area, and little things that might seem small (like an imbalance in the muscle that holds the shoulder blade against the ribs) can really FUBAR the joint in a dozen years or two. Injury is the first and primary concern with any imbalance I bring up.
But in a more immediate sense, it can also impede your performance; not like having no shoulders in twenty years isn't going to impede your performance (yeah, I have some athletes you might wanna ask about that . . .) The serratus anterior is a muscle you need for swimming, especially if you want to get that nice Serape Effect rotation going. Besides which, it's totally common for winging scapulae to go along with a protracted shoulder girdle, which probably means your rhomboids are weak too. And guess what other muscles operate in that Serape Effect thing. That's right . . .
What do you do about winging scapula? Here are some exercises and stretches that will probably help you (unless your problem arises from an impinged nerve in your neck/traps, but in that case you'd probably only have one wing).
Incline Shoulder Raise
Lie on your back at a slight incline. If you're at a gym you can use an incline bench. Otherwise, you can lean against a stability ball. Hold dumbbells (always start light!) in hands with arms extended. Your hands should be positioned directly above your shoulders. Now without bending your elbows, raise your hands; the movement should come from scapular protraction (pulling your shoulder blades apart). You can also add this exercise onto the end of a bench press--that is, protract your shoulder blades at the top of your bench press, using your serratus anterior to extend your range of motion. Although if you have winged scapula, you probably shouldn't be spending a lot of time on bench press; your pecs are too strong, remember?
Standing (Dumbbell) Scaption
Don't start with dumbbells. This is not an exercise that you use to pack meat onto your deltoids. This exercise is not intended to give you a good cut. It primarily strengthens the supraspinatus, which has got to be one of the most exposed and vulnerable muscles in your body. So do yourself a favor and take it easy when you begin this exercise.
Stand in a stable position, hands at your sides, thumbs facing forward (palms turned towards your body). Make sure your shoulders are back and down, your chest is lifted, and your back is in a neutral position. The movement is halfway between a front raise and a lateral raise. Raise both arms to the front and sides at about a 45 degree angle, simultaneously rotating your thumbs to face behind you (palms still rotated medially). Combination flexion, abduction, and external rotation! Whee!
Supine PNF Patterns on Ball
Lie with a stability ball under your shoulders and upper back, thumb of your right hand on your left thigh. Lift your arm up and over your head, rotating your thumb to face down. Similar to the above movement, except the movement is diagonal and you're reclining.
Isometric Wall Press
Stand about two feet from a fall. Raise your arms to roughly shoulder level and place them on the wall. Make sure shoulders are back and down, chest is lifted, back is neutral. Press into the wall by protracting the shoulders (not by leaning forward!) and hold. This is an isometric contraction for the serratus anterior.
Doorway Modified Chest Stretch
Stand next to a doorway or wall of some sort. Bend the shoulder and elbow and place the the forearm against the wall. Lean into the wall slightly and turn the body away from your arm. You should feel the stretch in your upper chest and arm. This is to stretch the pectoralis minor.
During this yoga pose, focus on lifting yourself with your back extensors, rather than pushing yourself up with your arms. Keep the shoulders back and down, the shoulder blades retracted, and the chest broad and lifted. Stretch long through the spine and then try to pull the breastbone away from the hips. Yoga poses are really too complex for me to adequately explain in this manner; follow the link for a more complete set of directions. Or--even better--go to a yoga class and have an actual yoga instructor help you! You should be going to yoga anyway.
Downward Facing Dog
Same note as above; I can't adequately explain a yoga pose in this blog. Partly because it's too complex, but partly because I'm not qualified. I can tell you that one of the many, many benefits of this posture is that it causes a continuous eccentric contraction in the serratus anterior, as long as you remember to keep your shoulders broad and low. Follow the link (or your yoga instructor's instructions) for more help than I've given you!
I should mention at this point that my scapula wing. You can't tell just by looking (they're not that bad), but if I do the wall test, you can definitely see my wings ("Every time the dumbbells clank, a bodybuilder gets his wings!"). So these are exercises and stretches that I do on a regular basis. And Downard Facing Dog is very difficult for me in yoga class, because my serratus anterior doesn't much care to hold an eccentric contraction for very long.
I really hope that these exercises provide useful material for your weight training programs, and help prevent injury and enhance performance. If you have particular questions or suggestions for this series, sound off in the comments or send me an e-mail!
Note: Videos for the exercises can be found here.