Yes, but only to a point. The moist, low heat of the crockpot provides a great environment to break down the collagen and connective tissues that make the meat tough. However, the muscle fibers cook faster than the connective tissues, and they begin to shrink and become tough when they're "overcooked." The trick is to find the balance — once your meat is fork tender, it's time to stop the cooking process. With my slow cooker (or my Instant Pot set to slow cook), that takes about 8 hours.