Plainsman loves the hijack. He’s like a sponge absorbing everything that he can about swimming and different swimming philosophies 
Just to start with… I can come across as critical (especially with writing) when I don’t mean it that way. I was just curious about what you meant (I’m a curious person and I like to know why and what people are thinking), I wasn’t trying to criticise you and I apologise if it came across that way.
Totally agree with you about the ease of recovery. You’re far better than me on the physiology involved but I know that training in zero g / no impact (cycling / swimming) allows more training / quicker recovery than impact activities like running.
The clarification that you meant for triathletes obviously makes a massive difference and I think your 8x300 set is a really good set.
To clarify what I meant and what I’d give triathletes, I didn’t mean to just get in and swim easy. I meant swimming, to use your example, 300s moderately working good form (I’ve communicated this to Plainsman before so I didn’t elaborate). You get the work out from trying to hold your stroke together (lengthening out in front without loosing circle of power, high strong catch, holding your core stable blah blah blah), and although it doesn’t give your heart / lungs a massive workout it certainly makes you tired, fitter and faster. When I first started training like this I was always shocked at how fatigued I felt getting out after what had seemed like an “easy” session. When I was fit I’d do something like this holding ~3:50-4:00 on maybe a 4:10-4:15 cycle (for 300m so the equivalent of 3:40ish for 300y). So it’s not “easy”, it’s definitely moderate but below threshold. Nowadays, when I never consider myself fit, I just swim and take a quick swig of a drink or 10-15 seconds before setting off again (ahem except that I haven’t trained since August (focus is on learning how to run)).
My actual set would be pretty similar to yours but with mine you wouldn’t get as much rest so you might be able to fit an extra 300 (although I might break it up with 50m backstroke here or there). The major difference between us is perceived exertion and focus. Yours seems to be more on speed, mine is on length / form. I figure the most important thing is correct form and strengthening all of the supporting musles that go with holding correct form.
What we’re discussing comes down a little bit to the divide between younger and older swimmers. Younger swimmers need to spend some time flogging out long/fast/hard miles but older swimmers don’t. I’m not sure this is something that you agree with but certainly the second part is irrefutable in my experience (older swimmers don’t need to do long/hard/fast miles). They can do moderate “form” miles and super fast speed work with nothing in between. I’m pretty sure Dara Torres is an example of someone who does this sort of training and its certainly something done by plenty of Australian olympians (expecially during “base” training (I agree with you, never used this term while swimming, picked it up on ST).
I’m not certain what applies to masters swimmers. Whether it’s best to train them like young swimmers or older swimming. I’d be interested on the opinion of anyone who agrees with my comment regarding older swimmers and has experience with masters swimmers.
Certainly my ex-swimmer friends and I can get good results doing moderate form work 3 times a week but as ex-swimmers who did the hard yards when we were younger, we’re a tainted sample. I have a couple of friends who were non-swimmers that I encouraged to focus on long moderate work rather than flogging themselves and they’ve done well but better than they would have done doing “harder” work? Who knows.
Wow. That really was a hijack. Sorry Plainsman.
Tigerchik - hope that some of that rambling made sense and hope that it didn’t seem critical. I guess when you boil it down - the set that I repeat ad nauseum and bore my friends (and you) telling them to try, is really a short rest set swum somewhere in the upper aerobic region focussing on form. The critical issue though is holding form, not holding your pace / making cycle.
I’m leaving work for the day so no more hijacks from me… for now 