1. Don't Skimp on the Stretching
The subscapularis is one of the muscles in your rotator cuff. Connecting the underside of your shoulder blade to the front of your upper arm, it is mainly responsible for internally rotating your arm. Unfortunately, athletes in throwing sports like baseball and football or serving sports like tennis and volleyball often injure their subscapularis muscles, causing loads of pain and frequently requiring lengthy rehabilitation to repair. To prevent these injuries from occurring, it's important not only to strengthen the subscapularis but also to stretch it.
2. Find a Doorway and Hold 'Em Up
An easy way to stretch the subscapularis is with a doorway. While standing in a doorway with one leg forward and your knees slightly bent, raise your hands as if you're surrendering to an imaginary aggressor and place one of your forearms against the door frame. Then lean through the doorway, bending forward at the hip just a bit. Make sure you keep your head up and your eyes focused straight ahead to prevent straining your neck muscles. Continue leaning until you feel a decent stretch in your shoulder, and then hold the stretch for about 30 seconds. When time's up, take a few seconds to rest and then repeat the stretch.
Once you've done the stretch once or twice more, start the whole cycle over again using your other arm. As with any other stretching exercise, it's extremely important that you stretch both shoulders to prevent muscle imbalances from developing, even if you only throw with one.
3. Knowing When and Where
Just like strengthening your shoulders or training your sport-specific skills, you'll need to make stretching your subscapularis a part of your regular routine for it to really make a difference in your joint's health. A good time to do the stretch is after you've finished working out. Your muscles will already be warm and ready to stretch, meaning you'll get great results and you'll avoid injuring the muscle during the exercise. If there isn't a doorway handy when you want to do the stretch, you can use other objects like trees, fence posts or building corners as a brace for your arm.
Make sure you don't stretch your subscapularis too far or too soon. Just like any other muscle in your body, the subscapularis doesn't take kindly to ballistic stretching and extreme pressure. Taking it slow and staying within your shoulder's limits ensures you get the stretch you want without risking further injury.
