Ironman Marathon Times

I posted this to Shelley's blog anonymously, but I put it here, because, well, I'm the author!

The topic is, if I can run X in an open marathon, how fast Y can I run in an IM marathon? Why am I putting this question here? For the first time IM'er and also those of you with a few under your belt.Here's a good discussion from the Slowtwitch forum: http://forum.slowtwitch.com/gforum.cgi?post=621985;s=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;;page=unread#unread

The operative algorithm is that IF you are EXPERIENCED at Ironman AND you have GOOD to SUPERIOR muscular endurance on the bike (enabling you to come off the 112-mile bike "relatively" fresh), THEN you can get within 10-15% of your open marathon time during an IM marathon.

Example: your open marathon PR is 4:00. If you are a bike monster, you can hope for 4:24-4:36 in an IM. If you DO NOT have that GOOD to SUPERIOR muscular endurance on the bike, then you can hope for only a 20%+ degradation in your IM marathon from open time. Let's take that 4:00 open marathon guy/gal (which I am close to!). 20% slower gives a potential IM marathon time of 4:48, and that's damn close to my IM marathon goal at my next race.

I have done 7 IM's. My first IM marathon time was like 6:30. At the time, that represented a 44% (!) degradation from my open marathon PR of 4:30. My best IM marathon time to date is 5:15. My most recent open marathon time PR was 4:10. So I'm still running at a 26% degradation rate, and I happen to consider myself a pretty strong cyclist.

My point in this post is that if you're doing IM for the first time and you have a recent open marathon time, it's almost futile to say "I think I can do Y in the IM marathon." Actually, for one's first IM, unless you have years of 1/2 IM training under your belt, it's pretty futile to predict your first full IM time anyway. Your goal should be to JUST FINISH. If you have a few IM's under your belt, and you are Joe Average who has an open marathon time over your age group's Boston qualifying time, sure you need to work on your running in your IM training (and by the way, that does NOT include running open marathons during the meat of your IM training--why? The recovery cost is too great, meaning 2-3 weeks before you are back at full volume/intensity, plus as I'm illustrating here, the ability to run well in an IM marathon is highly dependent on bike fitness, so why would you waste precious training time running/recovering from open marathons when you could be putting in more 100+ mile rides?), but mostly you need to become that NUCLEAR ARSENAL that coaches like Gordo Byrn and Rich Strauss advocate, and then you can hope to break that 20% barrier and get into the range of the truly elite.

This post also addresses what I had told Shelley earlier that focusing on "I want a faster bike split" is really inappropriate, too. What you want is to be stupidly strong on the bike, and then NOT USE ALL OF IT during the IM. This is what will enable you to run off the bike, and WELL.

Another skewed perspective of measurement: "I ride 4 hours then run for 1 hour; therefore, my run speed during that brick is indicative of my IM run pace." WRONG! Not unless you have the knowledge of what your IM bike pacing SHOULD be, and then you ride at that pace and then run, then you are getting close. What will get you closer, though, is doing a race simulation brick (see http://cruciblefitness.com), where you ride a full 112 miles at your IM pace and then run 40'. Even then, you can count on slowing down somewhat during the IM marathon from whatever run pace you were able to hold during that workout. Why? We all lose focus, and mental training to avoid as much of that as possible is another advanced technique that I am currently working on. Some folks call this the ability to "suffer." Hey, if it's something you want to do, it's not suffering, is it?