Mobilizing the thoracic spine in extension and rotation will instantly increase your upper body mobility. It'll help you with all pressing and pulling exercises.
The increased mobility will make it easier for you to position your shoulder blades for optimal upper-body power generation. Your pressing, throws, and strikes will benefit. Better positioning of the shoulders improves stability, which means better performance and injury prevention.
Try this:
How to Do It
Starting on all fours, place your right hand behind your head.
From here move the elbow diagonally toward your left knee. The movement should primarily come from your upper back and shoulder.
From the bottom position, reverse the movement and raise the elbow as high as you can. Make sure to press the left hand and arm into the ground (protract the shoulder) to increase upper body stability. Let your eyes follow the elbow at all times to get the neck into the game.