Coachmom
Good question.
The intent should definitely be to have enough front side resistance so as to avoid the extra step. The above video is really slowed down so it is difficult to get a feel for the amount of linear energy Sarah is generating in her walkin....it is substantial. She is able to get relatively stable at time of release but just can't hold it totally as you can see.
Sarah is clearly a very powerful pitcher. I can tell she's generating a great deal of "linear energy!" And, "linear energy" is a great description of it.