WX wrote:
So here's my question... I need to run around a 3 flat marathon, which means I need to be at least a 2:40 open shape. I don't think I can do that with 25 miles per week. I agree on cutting back some of the swim to focus more on biking, but if my goal is around a 9:30, it seems like I should be able to raise my FTP to 280 in 5 months on 6-7 hours per week of biking. If so, shouldn't I keep a 40-50 mile run week to maintain my competitive advantage?
Your assumption that you can run a 3hr marathon if you're in 2:40 open shape is largely reliant on your bike fitness. That 20 minute drop means that you can ride 112 miles in the time you want and still be fairly fresh at the end. You get raise your FTP all you want, but you still need to time in the saddle to develop the IM specific bike fitness that makes you comfortable cranking out 22.5mph for 5 hours.
You can be in the best run fitness of your life, but if you're not where you need to be with your bike fitness, your run won't be even close to your expectations.
-Andrew