Originally Posted by Dignan
This is and isn't true….Cuts that are high in connective tissue, such as legs/thighs in chicken and brisket/short ribs/shoulder in beef, have completely different cooking profiles than cuts that are very low in connective tissue, such as breast in chicken, and tenderloin/strip steak/rib eye in beef. At lower temperatures, the cuts that are high in connective tissue will be relatively tough compared to cuts low in connective tissue. As the internal temperature rises, there will be a point were all of the cuts will become tough and overcooked. But when the cuts that are high in connective tissue reach optimum internal temperatures for breaking down connective tissue, they will become tender again. Cuts of meat low in connective tissue will never become tender again. Chicken breast, Ribe Eye, etc.. will never become tender again at higher temperatures because there is not enough connective tissue to break down and turn into gelatin.
I used to believe this as well, until I finally challenged myself to prove it.
Your statement about "cuts high in connective tissue being relatively tough compared to cuts low in connective tissue" is true both at lower temps and higher temps. Yes, it's true, you can take a low connective tissue piece of meat like a tri-tip or pork loin and (pardon the expression) "cook it like a brisket"
and it will come out very tender, in fact, compared to the higher connective tissue pieces of meat it is even more tender. The same difference as when cooked to lower temps, i.e. a brisket flat cooked to 120 degrees internal is actually relatively tender, but not as tender as a tri-tip cooked to 120. By the same token, however, a brisket cooked until it is probe tender (180+ degrees) is similarly less tender than a tri-tip cooked until it is probe tender.
Do a search for "like a brisket" and you will see that multiple brethren have proven this with multiple cuts of meat.