Without reading the entire thread I offer my comments:
Since I finally applied learned, hand's on knowledge of anatomy and what women want about 14 years ago, I discovered that muscle "knots" are just tension and spasms in major muscles (usually). Manipulation tends to loosen the tension and reduce the spasm, kinda like exercise, but more passive.
Massage is a pan species experience, and while I think theraputic massage for pets is crap, there can be no denial that cats, dogs and other pet animals enjoy manual muscle stimulation.