Tuna,

I don't think fast action rods have anything to do with the injuries. I have several slow action rods as well, that I use for dry fly fishing. They hurt, too, when the elbow is acting up. As does rowing the drift boat, and drinking coffee. The tendonitis is an overuse injury. The steelhead rods cause it, and would cause it even if they were slow action rods, simply because they require more force or effort to use. The light rods don't bother me as much, the heavier ones do. My elbows start acting up when I use anything heavier than a four weight.

I think most people like fast action rods because they are easier to use for the longer casts. While an able caster can cast any rod, the faster rods seem to be a bit easier to use for most casters, based on my experience of introducing people to fly casting. I think it's due to the longer acceleration cycle required by slower rods. Slower rods require a more deliberate stroke and better timing, which is harder for beginners.

My preferred stick is a Sage RPL, no longer available. It is slower than many of the faster sticks available today. I like it's feel. I have cast the BL5, and just don't care for it's action for the type of things I do. Others may feel differently.

As to the implication that you make that a cast made by a faster rod is perhaps less graceful, well, I think that's a matter of opinion. I disagree myself. Certainly the pace required by my spey rod, which is quite slow, is different than the fast rods I own, but they are all pleasant for me. As is a nice cast with a bait caster.