[naiad]

I agree that negative pressure dives and CO2 tables really don't have that much effect on performance, and the pain of doing them probably outweighs the benefits. I used to do O2 and CO2 tables often, as well as negatives dry and in the pool. Now I do dry statics and O2 tables, but not many CO2 tables or negatives. I have not seen any loss of performance, my dry and pool statics and dynamics are the same as ever. In fact my dry static PB and dynamic with fins PB were done when I was not training CO2 tables and negatives.

The O2 tables do make a real difference for me. Fitness training makes some difference, but not much. I think that is just me, as others seem to improve a lot with it.