Any female pitcher wanting to excel in fastpitch today should
never be taught to step back - it's illegal in most sanctions (except for the example LK described).
The pitcher is required to either take, or appear to take, a signal and have separated hands prior to pitching. The ball can stay in the glove or pitching hand at this time. The pitcher then needs to bring her hands together for 1 to 10 seconds before releasing the ball. Prior to taking a forward step, both feet have to stay in contact with the pitcher's plate in women's play, according to ASA.
Prior to the step in men's play, a backward step may be taken while hands are brought together or after hands are brought together. (Probably where the confusion comes from)
The pitcher cannot make movements that resemble pitching without delivering the ball. The pitcher also cannot stop forward motion after separating the hands. A pitcher is required to take one step forward toward the batter with the non-pivot foot. This has to be simultaneous with releasing the ball.
However, a pitcher CAN step back removing
both feet from the pitcher's plate prior to hand separation to stop the pitch. (similar to a baseball pitcher from the stretch position)
IMO, two of the biggest things that impede a pitcher's progress is misunderstanding/teaching the step back, and being taught to close their hips on delivery - or "slam the door".