The greatest distance results from the greatest energy storage and release over the least amount of time. This translates to highest velocity, the same as a higher velocity bullet goes farther than a lower velocity bullet, all other things being equal.
The greatest tip velocity in a rod results, therefore, from a cast which has the least time from full rear deflex to full forward release. If the caster cannot push the rod forward quickly enough to match the rod's energy release, velocity will not be at the maximum level.
Look at it this way:
Take a rod. Any rod. Put the max rated lure weight for that rod on it. Set up as if you going to cast, but instead of going through a regular cast, just bring back the rod ever so slowly, and then bring it forward ever so slowly. You just went through the motion of a cast, with the arc of a cast and the weight of a cast, but if you released the lure weight at the end of that cast, it would just plop on the ground.
Now do the same exact thing; go through the cast again, but this time a little faster. You'll notice two thing: one is that the tip of the rod was deflected by the lure weight, and the other is that the lure weight now travels a greater distance. You have imparted greater velocity to the lure.
As you go through this same motion every time, but faster and faster each time, your distance will be greater and greater ..... up to a point.
That point is when one of two things happen. Either 1) the rod is so "floppy", like a willow stick, that it can't release more energy on the forward portion of the cast, or else 2) your reflexes and muscles are so slow that they can't force any greater velocity on the forward portion of the cast.
If #1 is the case, you've reached the maximum energy and deflection speed of the rod, and you won't be able to force it to give you any higher level of results.
If #2 is the case, only a longer rod will produce greater velocity, because for the same casting stroke, a longer lever arm has greater tip speed, resulting in greater velocity.
But .... look at #2 another way. Let's say you have two graphite rods. One has faster deflection and energy release than the other one, but they both store and release energy faster than human muscles can move or react. Theoretically, one can cast a lure further than the other one. In reality, they will cast the same, because no human being can exploit the difference.
It's not difficult to manufacture a fishing rod where #2 applies. In fact, it's easy. Very easy. Just a stiff carbon-and-epoxy shaft, like a stiff pool cue. I imagine you've seen them; cheap graphite rods from China, puffed up in advertising to be "wonder rods". but in actuality not very useful for fishing. Will they give you great distances? No, they won't. They're too fast for your body's muscles.
So the best rods for use by human beings are those that match our reaction speed and muscle control for acceleration.
I apologize for the long post; I hope I made things clearer! ??? jj