Poor posture is a sign of weakness and laziness. Because it is seen as being “Cool” to lounge around in class or hanging out somewhere, this is causing poor posture in young athletes today. DO NOT ALLOW THIS TO HAPPEN TO YOU. Poor posture will lead to an arm injury, especially in pitchers. If this is you, then you must read this article.
Notice the image below of the subacromial space. When the arm is relaxed and down, there is enough room for the shoulder to rotate internally and externally but when the arm is raised above the head, in a throwing position, the subscromial space is almost closed. This can easily cause an impingment of the rotator cuff muscle, mainly the supraspinatus. Poor posture makes this even worse. This is because the shoulders are forward and the acromion is positioned more on top of the supraspinatus muscle impinging the muscle even more. With poor posture and the constant internal rotation of the arm during a pitch, over time this will start to tear the muscle. This could lead to a complete tear of the rotator cuff.
Good posture will not only prevent injury, it will increase velocity. Good posture can be seen in the picture above. This is when your core is firm, your hips are rotated back and under you and your shoulders are almost on the back shelf. The back shelf is when your shoulders are pulled all the way back. You should have them always on the shelf just before the back shelf. To do this pull the shoulders all the way back and then relax and move them up a little bit. This is where they should always live. This posture will increase velocity because if you notice your chest is out and your hips are under you. This will help prevent your shoulders from leading your hips during your pitching delivery. This will prevent an impingment and allow full range of motion in your arm increasing velocity.
Remember to prevent a major arm injury stop being lazy and develop good posture through awareness of your posture and a good strength training regime that involves a lot of core and leg training. Good posture will not only save your arm but help improve your velocity.