Racing Ironman with Power

Now that the big day has arrived, you'll want to pretty much stick to EXACTLY what you have been doing in training. That means not exceeding pre-determined limits on the hills and keeping your watts within a certain range. Along with keeping the watts in a certain range, this means pedaling when you need to, and not pedaling when you need to. Yes, you read that correctly. Sometimes you don't need to pedal. If the IMWI course is 112 miles long with a lot of hills ?V too many too count when I was there ?V then there must be a lot of down hills as well. What goes up; must come down. So, unless you are going to really gain some speed to get up the next hill, you are probably better off coasting. Why? If two guys of equal run ability get off the bike at the same time, and one has biked 112 miles, and the other has biked, let's say 100 miles, who do you think has the fresher legs to run a marathon? My money is on the guy who pedaled less. You can see this in the Tour all the time ?V guys sitting in the pack soft pedaling at 70-100 watts ?Vthose guys have fresh legs for the final sprint. They have a HUGE advantage over the guys who are working hard at the front to keep the pace line moving.
So ?V unless you are not gaining any tactical advantage, there is no need to pedal on the down-hills. If you are riding in the 6:00 range or faster, this means if you are going about 30-31 mph on some of the down hills, then you can stop pedaling. The amount of energy (watts) that it takes you to get over that 31 mph is enormous and certainly not worth it. So, if you see your mph display poking over 30 mph, you can most likely coast. Also, if you see the mph display NOT moving while you are pedaling, then you are probably wasting energy. So, just chill and enjoy the coasting.
Questions: What wattage do I ride at? Great question! My answer of course is: what wattage have you been riding at in training that gives you an IF of .65-.72? I know, I am not supposed to answer a question with a question, but in reality, that's the answer. You want to shoot for a range of watts within that .65-.72 IF ?V so a conservative ride would be 65% and an aggressive ride would be more towards 72%. If you want to blow up on the run, then go ahead and ride at 75-80%. Be my guest.
If you lose power on your power meter, remember you still have your HRM so you should know about what effort that .65-.72 puts you in ?V right about 20 beats below your threshold, so make sure HR, power and cadence are lined up. If you feel as though you are working hard aerobically to push a certain wattage, then back off. If you feel as though it's easy to push a certain wattage and you can go harder, DO NOT. Just stick the cap on the watts of .72. Your run legs will thank you.
An example: an unfit guy named Mike raced IM USA in 2005 ?V his run fitness was good, biking not so much ?V low mojo after IMNZ left him off the bike for a long time. So, he had a plan to swim conservatively, ride exceptionally conservative, and run as well as he could for the course (1500 feet of elevation gain). Had he tried to ride to a time, like say 5:45 instead of chilling at 180 watts (70% IF), his run would have been in the 'toilet', and at all costs we want to avoid the 'toilet'. ?? He actually ran a decent marathon on a tough course.
Lesson of the story is ride to watts, not a time! If it's 25mph headwind or pouring rain, your mph will be different then what you are hoping for. But your wattage is your wattage and that won't change no matter what the conditions. Racing for 10-17 hours is a long time, so its important to be conservative. Get your calories down, stick to your watts, keep your cadence up and laugh at the people trying to crush the uphills. IF in fact, you bike too slowly; which I highly doubt you will; you have 26 miles to make up for it. Seriously! I have seen people hammering away for an extra 5 minutes on a 112 bike course only to blow up on the run because they pushed the bike too hard. A five minute gain on the bike, could mean losing hours on the run. But backing off and losing five minutes on the bike, could mean GAINING 30 minutes on the run. Something to think about folks: Ride smart; run strong.
Most important is getting to mile 18 feeling good. Here is where you'll pass all the people who went too fast. Its easy to swim strong, bike hard for 112 miles and run solid for 2+ hours, but its when the race gets into the 8, 9, 10 hour mark that it gets hard for most people. At MILE 18 is when the race begins. IF you can get to MILE 18 feeling good, that's when you pass a LOT of people and really have a great race. The ENTIRE race is about getting to mile 18 feeling great. You have a 4k swim, followed by a 112 mile bike ride, followed by an 18 mile run ?V all WARM UP for the 8 mile race you want to RUN at the end of the race That's the focus on race day.