How Fast Can I Go in an Ironman?

This is the dirty little secret that nobody wants to write about, much less talk about.

Ironman is a 2.4 mile swim followed by a 112-mile bike and then a marathon (yes, Virginia, ALL marathons are 26.2 miles).

We can, without hurting ourselves (but still needing recovery), complete one or more 2.4 mile swims, and one or more 112-mile rides in training. We could, but IMHO, should not, run an open marathon during Ironman training. Why? The recovery cost is too high. To fully recover from a marathon that was run at your best marathon pace requires at least 2 weeks of recovery, meaning little to no running, reduced swimming and biking. Plus, the way you run in that open marathon, while it is technically the same distance that happens at the end of an Ironman, is much different than that Ironman thing. So really, what have you accomplished by racing a marathon during Ironman training? Well, you found out how fast you could go running 26.2 miles by itself, you just cost yourself at least 2 weeks of solid training time that probably could be better spent working on your cycling endurance, and you might have even picked up a URI or musculoskeletal injury in the process. Like it or not, your immune system takes quite a hit in the post-marathon weeks, and you sustain well-documented muscular damage.

OK, now, back to figuring out how fast I can go. I can swim that 2.4 mile open water swim in practice, I can even "race" it. Should I go as fast in the Ironman swim as I did in the swim race? Only to the extent you are able to hold good form and stay aerobic (in terms of heart rate). Believe it or not, even those really fast Ironman swimmers (less than 1 hour) are holding something back during the Ironman swim. Why? Think about it this way. Based on your fitness going into the race, each of us has so many heartbeats or "matches" that we can use up. If we blow too many during the swim, we are left with less to work with for the bike and the run.

In my personal experience, when I do a 2.4 mile swim time trial in training, I am pretty much dead-on for what I can expect in the Ironman race, plus or minus 2-5 minutes for jostling, gaining position, getting hit, congestion, etc. Why? Because when I swim 2.4 miles during training, I have a pretty hefty level of fatigue I'm working on, and if I am going to ride or run long the very next day, this is a good simulation of the speed I should swim during the Ironman.

When you get to that start line on race day, you are all rested and rarin' to go. So it's not unusual for someone to think, "Hey, I'm rested, I should be able to go faster than during that practice swim." WRONG! You are going to ride 112 miles and then run 26.2 after this, dumbass! This is a general statement about Ironman racing. You will not be going faster than you did in training sessions. Ironman is an aerobic day of 140.6 miles, not a fun, fast 100-mile ride at 21MPH (I've done those, btw--lots of fun, but no indication of how fast I ride in an Ironman race), where all you've got to do afterwards is go get something to eat and probably a few beers (if you are like me), and then get home and lay around.

What does it mean if I go a lot slower on race day than in my race rehearsal swim? You could be too nervous, you went out too hard (and slowed significantly), you picked the wrong place to seed yourself and had to fight through more athletes to find your pace, you didn't relax enough, you weren't rested enough. Use the result as an opportunity to think about what happened, and consider if it requires adjustments to your training for the next time.

What does it mean if I go faster on race day than in my race rehearsal swim? Good on you! Please check your heart rate, though, because if you punched it too hard you might want to ease back a little more than normal for part of the bike ride. Remember those matches! It's also possible you were just motivated to swim up to your training/fitness level by the race than during training.

OK, so that takes care of the swim. How fast can I go on the bike? Again, you can and should do some practice rides, that include some running afterwards, of 100+ miles. Ideally, you ride 112 miles on an actual Ironman course. If you live anywhere within 5 hours of Madison, Wisconsin, use that Ironman course for your race rehearsal ride. Same for other Ironman courses, provided they are safe enough. Can I just ride and forget the run afterwards? Not really. See if you know you don't have to run, you ride faster, right? Come on, just admit it. Plus, riding fast at times is what helps you to build your cycling endurance. How do I know how fast to ride these "test" rides? There are 2 options: by heart rate, or by power (watts). Hopefully, you've been training the bike with one or the other and know where your heart rate or watts should be based on your fitness and other tests done along the way. Suffice it to say that you will be riding very aerobically. Again, consider all those heart beats or matches you have to spend over your 140.6 miles. If you spend too many on the bike, guess what happens when you get to the run? Out of gas, bonking, tremendous fatigue, lots of walking.

How much should I run afterwards? Well, you don't have to run as much as you think. 40-60 minutes is all. When in doubt, err on the lesser side. The point is to understand how your legs feel after riding 112 miles; not push into territory where you are risking injury or significant recovery time. The ride itself is plenty taxing and will require some recovery, so if you stack on too much running afterwards, you are asking for trouble. Besides, it takes most people only 20-30 minutes to resume their "normal" running stride. You will know right away that it sucks to run after riding 112-miles--how long do you need to keep running to get that through your thick skull? By the way, you can expect that when you get off the bike, your hip flexors will feel very tired, and your stride will automatically shorten. Here is where it pays off to have practiced that shorter, quicker stride in training.

What does it mean if my race time is slower than what I practiced during training? You might have brought the wrong cassette to the race (always select your cassette based on the course profile and your climbing ability), you might have swum too fast, your stomach might have decided not to cooperate, weather could be affecting you (in which case most athletes will experience the same thing), or you could have executed your race rehearsal improperly. Whatever the reason, you have burned less matches, and instead of fretting over it, consider now you might be able to go faster on the run.

What does it mean if my race time is faster than what I practiced during training? Again, you should be checking your heart rate/powermeter here to see what's gone on. If you were able to maintain your practiced heart rate or power and go faster, EXCELLENT! But if these things are out of whack, assess your condition and use that as a basis to set up your run expectations.

How fast am I going to be able to run that marathon? Here is where it gets dicey. IF you paced your swim correctly for your fitness, AND you paced your bike correctly and stayed aerobic/controlled your watts appropriately, THEN you will be able to run as fast as your current overall endurance, and particularly your cycling endurance, permits you to go. The one true statement you can make is that you won't go as fast as your open marathon time! Other things that will limit your speed on the run include, but are not limited to:

• how well you executed your nutrition and hydration on the bike.
• your mental state--you need to have a pretty good reason to keep going for 26.2 miles when you are already tired to begin with.
• starting the run too fast. You can always get the time back, but like those matches, once they are burned, they are gone.
• humility. If you convince yourself that you are not going to walk, and run let's say the first 9-13 miles, you might be surprised to find out that you need to walk and that perhaps you should have eased into things.

There are other things, too, but if you've paced your swim and bike properly, and executed your nutrition and hydration properly, and you have superior cycling endurance, then with some mental toughness you should be able to get within 20% of your open marathon time. Ironman marathon times are not "fast" by running standards (2:45???). So once you start running, you will be doing the best you can based on your fitness, mental and race execution skills.

What if your run performance was significantly slower than you thought you could do? It could be weather, you biked too fast, your nutrition was off, you lost mental focus, or you just plain don't have the cycling endurance yet to go as fast as you think.

What if your run performance was faster than you thought you could do? I don't need to tell YOU anything--you are probably ecstatic!

For guidance on race rehearsal weekends, which include a swim TT and 112-mile ride followed by a run, go here: http://cruciblefitness.com/etips/rehearsal-week.htm

One more thing--many people want to know how indicative a 1/2 Ironman race performance is to one's Ironman time. Things to consider:

• there is far less time during a HIM for big problems to express themselves. You might get away with some nutrition and pacing mistakes in a HIM, but not a full.
• you can go harder during all 3 sports, if you are a highly-trained athlete, in a HIM. The speed factor is much different.
• the cumulative fatigue you have as you begin the next sport in the progression is significantly less in a HIM than a full.
• if you "blow up" partway through a HIM, you can recover from it and still finish in a decent time. If you blow up in an Ironman, though, most likely it's game over and a death shuffle, if that's even possible, to the finish.

A rule of thumb is take your HIM time, double it and add 2 hours for a first Ironman. Another rule of thumb is that predicting your first Ironman finish time is a crap shoot. I think that if you can do one or two race rehearsals you have a much better shot at predicting a finish time than someone who doesn't do these simulations. Ultimately, it will come down to your overall fitness level, execution skills and mental toughness. As you will see if you read the Crucible Fitness guidance, when you finish the ride in an Ironman, that's the first time during the day when you will really have some idea of what you might be able to do on the run and have a good chance of meeting your goal.

How do you train so that you can swim at an "all day pace" at a decent speed and then bike strongly for 112 miles followed by running a marathon? That is something I defer to coaches and such (even though I know quite a bit about this--and I have coached a few athletes). If you are doing an Ironman for the first time or are looking to improve your time in another Ironman, I highly recommend you get a coach. And then while you are coached, ask questions, pay attention, and learn something about how it's done.

The other thing I suggest for first-timers is to get an Iron Mentor. No, it's not good enough to cruise around on the blogs reading and commenting. I mean latch onto someone that you know is successful at this game (and can even train with, if possible), and ask them to help you along. In addition to the training, there are lots of little details that can make your day more fun and rewarding. I am in the process of compiling a list of tips (everything that I can think of shy of how to train), and when it's finished, I will post it here, but in the meantime, get thee an Iron Mentor. Formally ask that person to mentor you. Be nice to them. Ask them stupid questions. Tell them how you're doing. Tell your coach you have one (trust me, they will be HAPPY you are doing it).

Have a great day and great training!