I've been slowly playing catch-up watching world cup ski videos from this past winter and I don't know quite what to make of this but it's amazing how many women's knees move together, nearly to the point of hitting, when they double-pole. Maybe something to do with hip width relative to standard ski track spacing? Maybe entirely unrelated if your videos show only one knee moving inward.
yeah it's totally related to core strength and the hip angle. In my case my core strength is good but my activation is not, so the force of poling combined with my bad right ankle lets everything collapse.
But yeah, the biomechanics on some of the best skiers in the world are just atrocious.
And, yes, tracks are spaced for men, not women. When I ski out of the tracks my feet are considerably closer together.
Oh! That's...lame (the spacing)