Reviving this thread (having just now discovered it) to share some of my own experiencing upon which I've recently had cause to ruminate.
Over the last few years, I have become aware that my body seems to experience physical strain quite differently and, while I struggle to articulate what is happening with any precising, the sense of it is that where I once experienced the consequences of strain in my muscles, the discomfort now seems more tied to the tendons and ligaments.
In days past, I would regularly over do things either with regard to intensity - as when prematurely adding a few too many kg to a bench-press - or duration - as when pushing a run a few extra miles or extending a hike by a few hours. In either case, the felt consequences were usually quite similar - there was a diffuse ache throughout the affected muscle or muscle group which would be exacerbated (sometimes to an excruciating degree if the over-exertion has been especially extreme) and it was always quite clear that there was widespread damage of some sort throughout the tissue. Now, when I over do things (which sadly, might involve little more than righting a bin that has fallen over or picking up my 4kg cat), my muscles seem little affected, but I experience acute pain around the neighboring joints and attached tendons. Movement itself is sufficient to cause the discomfort, no activation/tensing of the muscle is required. It really is a quite different sensation, almost closer to what one experiences when forced to remain immobile in a cramped space for overlong at times. At others, it reminds my of the difficulty I used to have with iliotibial band syndrome.
While lack of activity might seem at first glance a plausible explanation, I am inclined to discount it as I am fairly certain that this new kind of discomfort emerged months if not years before I started reducing my activity level - I recall not only being surprised and confused but also aware that it was actually changing the way that I moved. This occurred both with large movement (walking, running, lifting) and small (playing guitar, drawing/writing, typing). No real idea what to make of it; just another one of those things that reshapes your life and becomes such a defining characteristic of the experience of this condition that it seems as though it must mean something, even as it receives little to no recognition or attention from those outside.
