Not to pick on PG11 or his fine lady, but I didn't want to let the teachable moment pass, because the example is so striking.
Scroll up to the pictures w/ post #125, and you'll see a fairly common mistake, which is most frequently seen done by the fairer sex.
Lennyjoe's youngest is doing the same thing in #135, and I'm sure I can scroll around this thread for more.
The first thing that most people see is the pronounced backwards lean. If you look closer, however, what you'll see is that she's leaning backwards to compensate for lack of upper body strength because she's fully extended her service sized pistol all the way out, locking her elbows. If you squint properly, you'll see that the backwards lean is centering the mass defined by 2 lbs of metal in her hands, and her shoulders.
Ladies, unlock those elbows, and bring your sidearm in a little closer. Your center of mass will shift to something more reasonable, your shoulders won't be sore, because they'll no longer be the fulcrum of your personal biomechanical shooting machine, and you'll also find that you're recoil will be properly absorbed and distributed.