- May 7, 2010
To me, the tight-loop video (and gyro measurements) show the importance of loading (and unloading) the 'spring' of the rod. So, I don't think it is a 'myth', despite some of the comments above.
The 'spring' was conceived, or taken to mean stored energy that contributed to the speed or velocity of the cast, this led a lot of people up a dead end, it does minimally but is not the whole story, it's an over simplification and the whole story is more important in understanding what is going on.
The bend from leading the line to 'unloading' creates and defines the loop, there is a whole load of key things that happen in less than a second, all of them more useful than anything physically or line speed wise gained from stored energy.
First up I'd suggest is the compound effect of a bendy lever letting us efficiently impart energy longer, smoother and with less muscle.
We could focus on that and get somewhere but watch what happens when people start talking about and thinking in springs, it's a different set of physics principles.