Swimming question

Actually, what you describe WOULD theoretically work for most AGers. Endurance sports and endurance sports, and even though swimming has a much bigger technique component, it is still an endurance sport that will respond to 'typical' endurance type training, and that includes long endurance efforts. 

There are a few main reasons why coaches generally recommend to not do those 'long steady swims', which are good ones:

- Most people who shoot for 'swim an hour steady' don't keep a close eye on their swim pace. And since swimming is not weight bearing, it's simply too easy for a beginner swimmer to start slacking off when it counts. Their pace will drop, and technique will start to deteriorate, and then benefits decrease.

- Almost all 'serious' swim teams/clubs have more than 1 person per lane swimming, and usually 3-5. In that sort of setup, it becomes logistically nearly impossible to do a long interval of 500+, since even a 5sec/100 difference will have the slower swimmer getting lapped by the fastest one in the lane. Weirdly, swimmers rarely acknowledge this reality, but it's definitely one of the big reasons why swim sets are broken up into shorter intervals.

- In swimming to swim faster, you really have to push the pace when it counts. That 'hour steady swim' doesn't push the pace. It's a perfectly good workout on its own and great when supplemented with short speedwork, but for a lot of beginners, this swim becomes their one-and-only important swim workout. Unlike running, where the weight-bearing nature, plus our natural human ability to improve run form and speed with no special form training by just running more, and at easy paces, swimming doesn't improve anywhere near as much by just 'swimming a lot, easy.' 

- The short intervals also allow you to recoup your form after a brief break, but I actually think this is overrated, even though theoretically it's the case. (I find I improve my ability to hold form much better on those fatiguing long intervals where I'm forced to actively do correct form when everything is super fatigued.)

But you are correct in that if you are disciplined enough to keep a close eye on your paces, and work hard, there is no reason why you will not benefit from those longer swim sessions. I made huge gains with these type of 60-90 long-interval workouts of 500-800, but I watch my pace on ever single 100 - no tuning out and 'swimming for time.'

In my opinion, long steady state swimming isn't useless in that it's better than not swimming at all.  It's just not the best bang for your buck.

It's not just about pushing hard. You can do that on the bike too, and both cycling & running have longer intervals than swimming does. They'll have intervals of 10 minutes, 20 minutes, and even longer. Repeating these even. Swimming doesn't do that so much. It's also about swimming with good form. You do want to push, but also do so with about the best form you are capable of at the time. Breaking into the intervals helps to achieve that with the short rests allowing for a quicker recovery of the feel, but not so much that your body comes all the way down to truly resting all the time. Strikes a balance of how different aspects of your body recover. The fitness has to be built on swimming well. It's not one or the other, but both propping each other up.

Swimming threads are funny.  Everyone wants to be a faster swimmer.  The fastest swimmers all do interval work almost exclusively.  Most people learning to swim and trying to get faster don't want to do intervals and then give reasons why longer efforts make more sense.  But in the end, the fastest swimmers are still the people doing the interval work.

The fastest swimmers I know almost never swim further than a 200 in training, and even those are rare.