Racing a Half Ironman Before a Full Ironman

150 150 Rich Strauss

Endurance Nation at Ironman® Racine 70.3


“Should I race a half Ironman® before my full Ironman?”

I am asked this question very frequently, as the Endurance Nation coach responsible for planning the seasons of every one of our members and trial members, outlining their movement through our training plans across their race calendar.

The short answer is that completing a half Ironman, while a good idea if properly scheduled, is NOT a prerequisite for finishing an Ironman. I’ve been to a lot of Ironman® finish lines and I have never seen an Ironman® Ticket Collector making sure you’ve punched your Half Ironman® ticket before letting you enter the Ironman® finishing chute.

Half Ironman® as Ironman® Race Rehearsal

The most common reason athletes give me for wanting to complete a half Ironman® is to do the event as an Ironman® race rehearsal. In my opinion, this is a suboptimal solution. Consider on Ironman® race day you’re going to ride 112 miles before running a marathon. By definition, that’s a pretty easy bike ride. Then consider that you’re going to run a marathon after a 2.4 mile swim and a 112 mile bike. By definition, that run pace is pretty easy.

The net is that a 56 mile ride at Ironman® pace isn’t really long enough for pacing and nutrition mistakes to express themselves. In our experience, those mistakes usually express themselves after about mile 80. And a 13 mile run at Ironman® pace after a 56 mile bike, also at Ironman® pace, frequently isn’t challenging enough for mistakes to express themselves.

Therefore there is very little you can learn about Ironman® race execution by racing a half Ironman, if done at Ironman® pace, or even if raced as a half Ironman. The distances, and therefore your intensity level, are just too different.  Add to this the high cost of registration, travel, etc, and you’re basically paying a lot of money for a race rehearsal that is not as good, frankly, as what you could do for free from your doorstep.

So if you are going to do a half before your full, our advice is to race it as a half Ironman. Have fun going fast and doing cool stuff with your fitness!

Best Timing of a Half Ironman® in Relation to Your Full Ironman

If our advice is to race your half Ironman, the next question is when is the best time to race a half in route to a full? Let’s begin by discussing the implications of a half Ironman® within the context of an Ironman® training schedule.

The Training Plan Accommodation Hole

Racing a half Ironman® will require you to change many elements of your Ironman® training plan to accommodate the race:

  • Race Week: You’ll want to amend your Ironman® training plan so you have a good race and don’t waste your registration and travel costs. For a Sunday race, this could mean dialing back your Ironman® training beginning the previous weekend, or staying on it through Wednesday of race week, depending on the A, B, or C priority you assign to the race.
  • Post Race Week: after the race you’ll need to make adjustments to your Ironman® training plan to recover from the half. Your Number One Priority is to be back on track with your Ironman-specific long bike and long run training by the following weekend. These must not be skipped and that may mean standing down hard Monday through Wednesday or even Thursday.

The net is that racing a half Ironman® within your Ironman® training schedule will punch about a seven to ten day “accommodation hole” into your schedule:

  • You’ll likely skip or greatly reduce any bike or run interval sessions in your race and post race weeks. So that’s 2 x “get faster” bike and run sessions, gone.
  • You’ll miss your Ironman-specific long bike opportunities for race week, because you’ll be racing instead. This is a missed opportunity to continue to dial in pacing, nutrition, adapt your body to long miles in the aerobars, etc.
  • A half marathon at half Ironman® pace is a solid long run so you’re good there…as long as you are smart the week after the race and get in your regularly scheduled long run. Do. Not. Miss. This!

The Variable Cost of the Accommodation Hole

Punching this hole into your Ironman® training schedule 12-16 weeks out is not a big deal, you have plenty of time to put on your pointy Ironman® hat and get down to business. In fact, we want our athletes heads to not be in an Ironman® training place until 12 weeks out, so we encourage them to schedule races and other events and train for those, not Ironman. And a half Ironman® is an excellent tool for this purpose, as the distances are long enough to increase accountability, but manageable enough that they can preserve their heads and SAUs (Spousal Approval Units) for the much more focused training to come closer to Ironman.

But as you get closer to Ironman® race day, your training becomes much more race specific, with critical volume and race rehearsal opportunities carefully scheduled. These training events become extremely important. Scheduling a half Ironman® within this window, and punching that accommodation hole into your training schedule, becomes very costly to your ultimate goal of a successful Ironman. For this reason we don’t recommend our athletes race anything, frankly, within 6-7 weeks of their Ironman.

This All Just a Game

That said, this is all just a game, it’s supposed to be fun, and if racing a half Ironman® in route to your Ironman® sounds fun, go for it! As I said, we encourage our Ironman® athletes to use halfs and other fun events as tools to disengage their heads from Ironman® training for as long as possible. So if you are going to race that half:

  • Be smart with race selection.
    • 12+ weeks out = totally fine.
    • ~7-10wks out = “mostly” fine, but you’re getting into the yellow zone. You must get back onto your regularly scheduled Ironman® programing the week after the race.
    • >6wks out = no go. You will compromise your Ironman-specific critical volume and rehearsal opportunities.
  • RACE IT! Let the big Ironman® dog run and have fun! But don’t do the half as an Ironman® race rehearsal because it’s not a very good one and you’re better off not spending your money, doing a free race rehearsal from your doorstep instead.

Rich Strauss
Endurance Nation Coach and Founder
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