IMHO meaningless check points, toe touch and heel plant.
The 'check point' is the release of the stretch.
What good was starting at foot plant in the swing on the right.
Both swings sync to foot plant.
Good hitters don't coil and then hold coil.
Landing heel first is not common, but it is not an issue either.
Teach the swing will 'plant' the foot. More later....
The front leg/knee is lifted up into the torso. completely supported by the back side/leg. The foot is lifted upwards into the torso mass through the back leg/side taking control of the stride leg/foot. Since the back side is in control you let the toes touch down first, because it's not the front leg that drops the heel, it is the back leg (back side) that drops the heel. The swing starts at toe touch, so you could say that dropping the front foot is the trigger. The process of planting the front foot is the swing starting. The real trigger is the back leg/hip and slight flexing of the back knee.
The toe touch position is also the launch position. The shoulders are turned in 30 degrees, the hands are shoulder height, the back forearm is level with the ground, the weight is back, the body/hips are in front of the back knee, the back knee is in front of the back foot, you are coiled, it is the point where you start the swing, it is the point where you go from pre swing to swing.
So I think highly of the toe touch position. Even if you don't teach the toe touch, it's a good check point for the swing.
I do teach to land on the toes. As you can see in the clip it takes 4 frames for the heel to plant at 60fps that would be 2 frames at 30fps. So it's not an instant action toe to heel. It takes a little time for the back side to drop the heel. You could even say that it's not fully weight until 5 frames. And this is because the back leg controls the dropping of the heel, the back side lowering the foot down.
