[1] Parallel turns require solid contact from the skier's lower leg to the ski to rotate it on-edge.
The introduction of composite skis, metal edges, releasable clamping bindings, and stiff plastic boots combined to allow parallel turns even on beginner equipment.
Today parallel turns are taught to teach novice skiers the effect of weighting and unweighting their skis.
Lifting the body through the middle of the switch partially releases the skis arcs, easing the transition to the opposite direction.
Applying an edge of these "shaped" or "parabolic" skis brings a curved surface to the snow, resulting in a carve turn.