Pitching; ASA style

[Dakota]

I only know of one significant difference between the NFHS and the ASA pitching mechanics...

In NFHS a back step is allowed by the stride foot. If the backward step is taken, it must begin before the hands come together.

There are a few other minor differences (e.g. definition of the start of pitch) and a slightly different definition of a crow hop, but otherwise, they are very similar.

What you are describing (lifting the toe of the pivot foot while keeping the heel in contact with the plate) is also legal in ASA. The key is keeping contact with the plate.