My kids (16 and 12 yo) have had training before. I’ve got to say I’ve never seen them work so consistently on drills and throwing.
Quite honestly no one ever really gave them specific stuff to work on or at least never let them know the expectation was that they would do it.
They have even both been taking notes after watching video of themselves throwing each time.
I’m really impressed with the level of understanding they’re already starting to display about what they’re trying to accomplish with the drills and how it carries over to their throws.