Wait, hip abduction / adduction, I'm having trouble visualizing that. That's just how separated the legs are, right? Like, when sitting on the ground with the legs stretched out and touching, the hips are fully abducted, but if you spread your legs apart, that's hip adduction?
In that case, in the stretch my PT has me do, the hips are fully abducted, and whichever leg I'm stretching is raised. My lumbar spine keeps its natural curve, and the chest is lifted, so the whole spine is in its natural shape, the hips are vertical, etc.
Yeah, I think the idea of rotating the raised leg externally & internally from the hip is mainly to stretch & relax the biceps femoris, since as I externally rotate it shortens the muscle and decreases the stretch.
I don't feel discomfort in the hip and thigh, though.
I mean, it strikes me as similar to Uttanasana, the normal Yoga standing forward bend, i.e. "touch your toes" -- you engage the external rotators of your lower leg while simultaneously engaging internal rotation of your femur, so the knee doesn't really rotate, but the seat widens (or, that's the sensation -- obviously the sit bones cannot actually move away from one another, but the glutes release and the muscles of the lower back release too.)
I know what you mean about the weight-bearing vs. non-weight-bearing stretches. That's exemplified in yoga by these two postures:Uttanasana (standing forward bend)Supta Padanagusthasana (reclining hand-to-big-toe pose)
And it's a toss-up, really, in my experience. On the one hand, the reclining hamstring stretch is safer for the lower back (especially if you put a rolled-up blanket underneath the lumbar to keep that curve), but in the standing forward bend, you can really engage the quadriceps and, with some mindfulness, let the hamstrings increasingly relax & release, and then you have the added help of gravity pulling your upper torso forward and down, which can intensify the stretch over the reclining version.
But lengthening my hamstrings is such slow work it's hard to really say which "works faster."