Stand with either the right or left side of your body facing a mirror, arms resting at your sides. Now, keep both arms straight and raise them overhead. If you got your arms parallel with your ears without your ribcage moving, you've passed this test. If you didn't—if your ribcage moved before your arms were overhead or your arms didn't finish parallel with your ears—you've failed. Don't dive straight into overhead pressing because you don't have the upper-back and shoulder mobility to safely press a bar overhead yet. I'll help you address that after another quick test.