Violin Stance Through The Ages
I'm fascinated at how most upper string players are taught to turn out their left leg in order to play violin or viola, but are rarely given a reason. Just to illustrate my point on how virtually everyone turns out at least one foot while playing violin, here's a gallery of images through the ages. Some are exaggerated artistic renderings, some are photographs. It's been happening for hundreds of years, and perhaps, it's not a good thing.
So you can see that this pattern is not just limited to Suzuki training in violin, but is instead a timeless practice extending far beyond that technique. There's a combination of "showmanship" histrionics and drama, which sometimes makes for unusual stance and posture.
Is it your fault if you play this way? No. Are you definitely going to hurt yourself or your students if you teach this way? Not necessarily.
However, as biomechanists gain a more profound understanding of the body, I suggest that we adapt our practices accordingly. Many of these were (and are) great musicians, and perhaps they never played with pain. However, I know many folks who do work with pain while standing and playing, and so I suggest a reassessment of these "right" practices. Movement while playing is natural, but start with a good foundational base to return to after you channel your showmanship pose.