Nolan Ryan threw harder than Mark Prior ever did.
I've cited that fact in a variety of contexts, but driving around tonight, I realized it might be relevant to The Epidemic.
Pitchers don't get hurt just because they throw hard. I've said that before about the Inverted W and the other arm actions and tricks that often create a velocity boost (in the short run) by creating a Timing problem.
I believe a perhaps big part of the problem with the tricks that are being to produce rapid velocity gains is one word.
There's no doubt that the body has the ability to adapt to changes. However, that adaptive process usually takes months or even years to work; to rebuild (or remodel) bones, tendons, and ligaments.
I believe that part of what's driving The Epidemic is the speed with which the various Killer Cues and Drills I've documented work. I believe they may produce velocity gains faster than the body can adapt to them.
There are lots of stories of pitchers quickly breaking down after achieving rapid velocity gains, one of them being Mariano Rivera right after he was drafted. Michael Wacha is another example of a pitcher who experienced problems soon after a mechanically-driven velocity boost.
I don't think high velocities are necessarily bad, but the speed at which they are achieved may be important.