HOW: Stand up leaning against a lacrosse ball or mobility ball into the wall. You want the ball to be underneath the mass of your chest, the targeted muscle is actually DEEP onto your ribs. Place the arm that is being worked behind your back. You have the option of going up and down or side to side, whichever feels more productive for you. To make this more aggressive you can lean into the ball which will apply some more pressure on this region.
FEEL: It is common for the soft tissue in this area to be sensitive. There are many nerves that run around this region, do NOT continue if you feel numbness and tingling. Take a quick break until that sensation diminishes.
COMPENSATION: Don’t roll the ball too fast or too slow, find the right speed that fits your best needs.