I was hoping someone would pick up on this! This is going to get a little confusing probably, sorry about that.
Okay, so, like I said, there's a LOT of magical thinking that surrounds massage, and a big part of that is made up of the magical thinking that surrounds Pain as a concept. To whit: a "knot" is not, medically, a Thing That Exists. If you were a very unethical surgeon and you performed a biopsy on a person who said that they felt a knot in their longissimus thoracis, you would cut into them and just find standard-issue muscle tissue. Muscle tissue is contractile - it stretches, it contracts, and even skeletal muscle (the name for muscle that's under our conscious control) will very often perform actions not under our conscious control. Prolonged periods of noxious irritation can make portions of muscle tissue contract, with the sensory nerves of the skin surrounding that muscle tissue placed onto high alert in an attempt to avoid further noxious stimuli.
That probably seems like a weird way of describing a physiological phenomenon! Sorry, some of this is just going to be Like That. See, pain is weird. The easiest way to describe pain is to call it your body's "warning system". When something happens that has the potential to threaten your body, pain serves as a high-priority sensory alarm that prompts you to (hopefully) remedy whatever situation you're in. Place hand on hot stove -> pain in hand -> quickly remove hand. However, things that cause pain are very rarely as cut-and-dry as that. There's a lot of different types of pain, for one thing. The pain of getting stabbed is different from the pain of standing in one place for four hours which is different from the pain of a stomachache which is different from the pain of a headache which is different from the pain of a broken bone which is different from the pain of being tired from weightlifting. You likely experience multiple different forms of pain every single day, to different degrees, for different amounts of time, and the system for prioritizing and contextualizing every single painful signal your nervous system receives is unimaginably complex and we barely understand it.
Pain provokes a number of autonomic physiological responses (that is to say, it makes our bodies do things automatically). Sometimes it'll make us sweat, sometimes it can make us dizzy, and very often it'll provoke certain types of involuntary muscular contractions. During a physically traumatic event it's very common for muscles around a damaged area to go into what's called "protective spasm" - literally contracting uncontrollably in an effort to protect from further damage. Thing is, the body is actually Not Very Good at knowing when to STOP being in protective spasm, and spasms of ANY length are themselves very fatiguing and painful. Whoops!
Another concept that's important to know about pain is that of "sensitization". If we think of pain as a warning system, sensitization is that warning system becoming more responsive to threats in a certain area if that area happens to be in pain frequently. However, the thing about making a threat-monitoring system more sensitive is that it will now, in turn, pick up on threats more easily! So, an area that's experiencing pain frequently will now experience pain MORE frequently because the body wants to stop experiencing pain so frequently in that area! Why, that sounds like a vicious feedback loop! Thanks, body!
So, what does this have to do with the idea of "knots" and how massage might feel like it's "working out" something in your muscles?
Well, sorry to do this to you, but I need to make ONE more aside. See, massage doesn't actually directly act on muscle tissue. I know, I know, that's supposed to be our whole THING, right? The thing is, it's kind of physically impossible for a human being to mechanically make meaningful, controlled alterations to muscle or connective tissue - the force required goes into the low hundreds of pounds per square inch, which MOST humans are not capable of delivering. Sure, we can cause tears or bruising, but any sort of shearing of tissue adhesions is right out. There's also the fact that muscle tissue actually doesn't contain much in the way of sensory receptors - there's a few pain receptors here and there, but it's mostly stretch receptors at the tendinous attachment sites. So if massage isn't working on muscle, what IS it working on?
Skin, of course! Well, specifically, the wealth of sensory receptors the skin contains - light pressure, deep pressure, heat, pain, stretch! Manipulating your sensory experience is, as it turns out, a great way of provoking positive physiological changes, which can include breaking that cycle of sensitization and ease the body out of a state of protective spasm. Rub the skin around a fatigued muscular site for a few minutes and hey presto things feel better!
This probably feels like a somewhat incomplete explanation, and you likely have some follow-up questions. Congratulations! You're now invested in the nightmarish complexity that is pain science and nothing will be simple ever again
