FED Part I question

[DownTownTonyBrown]

Someone want to explain #32 to me

With a Runner on Base, it is a Balk When:
32. The pitcher in the set position, attempting to pick-off a runner at first base, keeps his non-pivot foot stationary but steps back with his pivot foot to gain leverage.

The answer given was True. The references were given as 6-1-3 and 6-2-4b.

Am I misunderstanding the word "back." I took that to mean in a direction away from home plate to a position behind the pitching rubber. This is a very common move for a Left Handed Pitcher, LHP - left foot (pivot) is placed behind rubber and throw is made to 1st. Don't see that it would help a RHP much.

Perhaps "back" was meant for a RHP and the direction was towards the pitcher's back, towards 1st base, that he was turning in a clockwise direction. This would be a balk.

What part of this question am I missing? "... to gain leverage?"