Possibly then one could think then of the stride leg being thrust forward as creating a forward momentum from its weight and velocity.
Think of the stride knee thrusting out rather than the leg as a first step in your stride. You should get to and through a tilted "h" position as your arm gets to the 6 o'clock progress point at the end of the backswing and beginning of the upswing for pitchers using that style. Your stride foot should not be ahead of vertical to your knee at this "h" position with the body almost facing the catcher. Similar to the sprinter in the photos on an earlier thread. Then you reach out with your foot which initiates your turning sideways to the target. There is such a thing as reaching out too much with your foot at this point. At foot plant, your knee should be slightly bent and avoid landing heal first. Landing foot can be sideways prior to landing but should be at about 45 deg or so at landing. This is the way I see it.