Forgive my ignorance, but I don't understand how a reverse crunch significantly differs from a regular crunch. After all, in the completed position are they not virtually the same? Wouldn't the reverse crunch too have the ribcage pulling effect that you spoke of in your shoulder savers letter?
Again, I am looking to keep my abs in great shape, but certainly not at the expense of my shoulder. What about hanging reverse crunches - same thing?