Couple of thoughts:
1. Once I learned to dive FRC, I've felt much safer due to the energy conservation for most of the dive and because my first action at the surface is to inhale fresh air, not exhale first and then inhale. Getting that first breath is so important if you are on the edge. But, I've never been on the edge with FRC simply because diving this way forces you to be very careful with your oxygen consumption and mindful of diving technique. I think FRC makes me a better diver not only for performance but for safety. And I find it easier on my lungs - I haven't had any sort of lung squeeze since I started - and much more enjoyable. But it does take some time to learn it. I am happy that FRC has lead me to longer and more enjoyable dives than by inhaling - it just takes more practice.
2. I question the use of full negative pressure dives for recreational divers and for most competitive divers. I believe they are dangerous and too easy to do for divers who don't yet have the body awareness to do them safely and even for those who should do. I never use them anymore. I find FRC much more effective and gentle at preparing the body for deep dives. I think if you want a strong dive response, lose the wetsuit.
3. The big "thing" about training, for lack of a better word, is intensity and specificity. I've written this before on this forum, but I think for most people, CO2 and O2 tables are not intense enough for competitive training. Now if you simply want to prepare for a season of recreational freediving, I think that FRC statics are much more useful, preferably on the bottom of the pool with a buddy to learn how that works for you at different intensities. Be as specific as possible. Personally, I don't pool train anymore and prefer to swim in the ocean and go freediving as often as possible for my training because I'm aiming to improve over years and years. I think trying to get significantly better over days or weeks is too risky for me.
Mind you, I do have the benefit of having trained intensely years ago and been through all that. But if someone came to me and wanted to become an excellent freediver, I would go about it in a vastly different way. I would make it much more enjoyable, for starters. I can outline my approach if anyone is interested, although it would of course depend on your personal goals and preferences.
Howard, I think putting yourself through exhale statics is perhaps valuable only in experiencing what that feels like. I'm not sure that it will have a direct impact on your diving. Remember that while Will Trubridge does incredible exhale statics, there is a lot more to diving deep and long. I'd say it's not necessarily a direct link to his excellent performances.
Pete
