HS (PC, pitched 1 yr. D3) wants DD to step across power line on drop ball and trying to teach her curve ball same thing. We go to a paid PC who is on here and is damn good and teaches everything on here. What is the purpose of this? Can this lead to injury?
Doug Gillis has a drill that exaggerates stepping across the powerline for the above mentioned reason (to feel throwing across the body). To my knowledge, he does not instruct an extreme step across the body on any specific pitch.
Significantly stepping across is more of a teach than a technique. Stepping across and essentially cutting yourself off will possibly increase Movement but does not help with Command and Velocity.