It was while watching a women’s slalom in Crans-Montana in 1987 that I first saw Erika Hess make a move that was different from the the moves I had observed in other racers. In those days, when a racer made an upward move by extending their legs it was assumed that this was a throw-back to the days of the up-unweighting movement that was used to release the edges of the skis. But it was clear to me that Hess was not up-unweighting. Instead, she was moving to her new outside ski in the last third of the turn, loading it by extending her leg, going straight at the next gate, then rapidly pivoting the ski. This is essentially the same move that Ligety and Shiffrin make. But the angles of angulation are much less dramatic because of the conservative sidecuts of the skis back then.
Here is a short video clip. The image quality is not very good. But if you watch carefully you will see Hess’s old outside ski lift as she extends on her new outside ski. In some frames you can see how she rapidly piviots the ski once the over-centre mechanism is engaged just as Ligety and Shiffrin do.