You may have a look at that new fly casting video here:
"Your rod should load during translation and then rotate by wrist to fire the rod."
To me this is a wrong understanding of what happens in most of our fly casting.
If we start our rod movement by translation first (no or very small rotation at the same time), this will lead into such small rod bend, that it's not worth talking about.
Besides that we don't want to load our road for then having our rod to shoot the line like a bow shoots an arrow post loading it!
Instead we mainly rotate our rod in order to create the desired line speed. As a consequence it bends. That bending behaviour comes along with some advantages and some disadvantages as you may study here:
The only cast in which we truly load our rod to then fire it off, is the bow and arrow cast. In this cast we pull a huge bend into our rod and then let the rod shoot off a relatively small amount of line. The amount of line is especially small compared to the amount of bend we pulled in.
In regard of RIO I believe they could have done better. We have tons of slow motion videos on the internet where you can see perfectly what our rods do within the cast. And most important you can also see what they DON'T do!
You may check some of those videos on vimeo published by Aitor Coteron, Lasse Karlsson, Gordon Judd, Niklas Eriksson or Bernd Ziesche for example. It's all available for more then 10 years now.
The details of fly casting may not be worth knowing to every fly fishermen, fair enough. But for those making money by teaching fly casting I think, it should be! Also a company who likes to describe itself as the leading fly line company may want to have an updated (detailed) understanding of what we do with their lines on our rods.
I understand that it is hard to erase that old wrong understanding of the importance of road loading and how it's done, but it'll be harder to keep me from trying! ;)
Great week and lot's of rod bending towards the fish to you all!
All my best