I’m not sure if the front leg is the brake or the back leg being dragged behind. Maybe the front leg is the brake when it straightens. It’s one thing I can’t practise off the roof of my boat"push up from the front leg", this is the breaking of which John spoke. Breaking creates acceleration.
Nice links there. It’s worth remembering of course that the line is not attached to the rod tip but during hauling is actually pulled through the rings, consequently the line is travelling quicker than the rod tip. Line speed is tip speed plus haul speed.
Therefore the haul can actually determine when the loop begins to form and not only the rod tip. In a non-hauled cast it is the rod tip that determines separation of the two legs (RSP). But this does not necessarily apply to a hauled cast. Finish the haul before RSP (or indeed simply slow the haul), with a rod angle such that the tip will deviate below the line path and the separation of rod/fly will occur here and not RSP.
[If on the other hand, the angle of the rod is not such that tip will curve below the line path, but instead such that the tip will rise, then a tailing loop will form. It’s my current belief that the optimal time to stop the haul’s acceleration is at the very point when the tip will deviate down. It’s for this reason that tailing loops can be seen at the world championships, frequently! The longest cast is optimised just inside the border of a tailing loop. I never make fishing casts close to that border, but in championship casting I will be right on the edge.]
Therefore the conclusion is that the haul can have the defining role over loop formation. Often anglers imagine that the haul is merely an add-on to stroke. It is far more than that, if anything it is the stroke that is an supplement to the haul!
Fun fun fun!!
Cheers, Paul