NOTE (2.7.2014): What you will find below is one strategy. I don’t think it’s the best strategy. In fact, three years after originally writing this, I don’t even think it’s a very good strategy.
This is not the way I currently train for 70.3s. I’ve gained mucho experience and knowledge in the last three years, and you can read most of that in the articles listed here.
There are much more effective ways to train, even with time constraints. And I’ve realized that setting time goals for a 70.3 is maybe not the smartest thing to do, at least for me. A time range is reasonable, but race day is full of unexpected events and factors you can’t control. Read on, but at your own peril.
Ok. I’ve noticed a lot of people are landing here looking for the answer to that one simple question…”What is the best way to train for a half iron distance race (70.3 miles) and finish in under six hours?”
I wrote a longer, more detailed post about one strategy to do this a while back. But if you’re looking for a simple (and logical) approach, I’m going to summarize it here. I’d advise going back and reading the whole post, which contains a little more detail. Keep in mind, I’m not a certified triathlon coach. I have absolutely no credentials other than the fact that I’ve actually done it while weighing over 200 lbs, eating higher quantity and lower quality of food than I should, and skipping a workout here and there.
Here’s my strategy: Prioritize the race (and your training) in the order of time spent in the race itself. That means concentrate on bike first, then run, then swim.
The bike is going to be about half of the race, right? So make biking the main focus of your training. That means you are probably not going to get a PR for your half marathon during this race. So be it. If you wanted to PR a half marathon you’d be training for that exclusively anyway, right?
Running will probably benefit from having a really solid base before you start training for the race. Build that up in the off-season, and you can put the running portion of the training on auto-pilot. It probably isn’t necessary to rack up a ton of miles running, but it’s a good idea to be mentally prepared for 13.1 by making sure you still hit a long run every week, preferably on tired cycling legs. For me, I did that along with a 10% brick of my rides, and it worked out. Again, I was a long way from PRing the 1/2 marathon in my race, but I’d banked so many minutes on the bike that I had a huge cushion.
Swim–fuhgetaboutit. If you can swim the distance, you will be fine. No need to spend hours in the pool so you can shave off 3 minutes of swim time when you could spend those hours biking (or resting). If anything, spend your swim time in the open water so you are comfortable with it.
Keep in mind, the point here isn’t to “do your best” or “run the perfect race”. If you want to do that, you should hire a coach, measure everything you eat, take vitamins, etc. Not knocking anyone who wants to do that either, but that’s a different (and very worthy) goal than just trying to arrive at 5:59:59.