I've been squatting for several years and have done regional level competitions and some quasi-formal training and coaching. Normally I can get any additional answers I need from other fitness friends books by guys like Pendlay and Rippetoe.
Recently I've started getting a pain-less popping sensation in my adductor magnus area. No idea if that's the muscle it's really coming from, but it's in the triangle between my hamstring, adductor, and glute, one just one side.
It feels a bit like some muscles are moving around on top of each other.
It doesn't happen constantly, it doesn't hurt, and it doesn't seem to affect anything. It only happens in the bottom of the squat ("the hole").
Does anyone have any references to a common fitness injury or mobility issue that could be going on?