The load occurs on the front side. It’s not a shift of the weight rearward. Watch the best hitters in the world like the gifs of Ryne Sandberg. The load is a slight turn inward of the frontside while moving forward. Girls hear “load up” and set all weight on backside which is weak and limits the bodies ability to move forward. I teach a toe tap (stride) toe to toe with weight slightly forward in stance. The front side load will occur without teach. Just tell hitter to get away from her hands and keep front shoulder on the ball