Marinades don't penetrate nor do acids tenderize,except for making the outer mushy. Papain, if not time controlled, will turn the meat to mush also. Sorry to be the bearer of bad news but at least you have something that will tenderize. Nothing is going to make tri tip melt literally like butter.
The diaphragm is the major muscle responsible for breathing. It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. During inhalation, the diaphragm contracts, so that it's centre moves caudally (downward) and its edges move rostrally (upward).
Diaphragmatic Breathing and Core Muscles. The way you breathe affects the tone in your deep abdominal and pelvic floor muscles. Our core is comprised of the diaphragm, pelvic floor, transverse abdominals and multifidus. For optimal health the diaphragm and pelvic floor need to move in sync.