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The #1 Workout To Prepare for Ironman

Want to know how an Ironman is going to feel? Give this workout from Gordo Byrn a try.

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Gordo Byrn, the founder of Endurance Corner and author of Going Long, uses what he calls Big Day Training (BDT) as a checkpoint for his athletes training for covering 140.6 miles. Not only does this Ironman prep workout help to train your mind, you’re also teaching the body pacing and how to digest nutrition over a long period of exercise.

“This is the only way to get a taste of how it’s going to feel,” Byrn says. You might do this workout 2–3 times to prepare for an Ironman triathlon. “I like 3/7/11 weeks out from the goal race for an athlete that’s new to the technique. Experienced athletes can do it more often, but need to be careful that they don’t end up racing-the-race before the actual race!”

Start out by doing this Ironman prep workout at an easy pace with long breaks (including meals) in between sessions, then move to a race-specific focus for your second time around.

RELATED: Triathlete’s Complete Guide to How to Train for an Ironman

Big Day Training workout: Round 1

• Swim 1 hour

• Break, with meal

• Bike 5 hours, continuous with very minimal rest or stopping

• Break, with meal

• Run 1 hour easy

“What most people find the first time they do that session is that they’re blown away by how torched they are once they get off the bike,” Byrn says. “Because their bodies have never trained that long, it’s never had that much output. Make some notes about how you do the run. When you get to the end, you’ve got 20 miles to run on race day. Are you ready to run 20? If the answer’s no, you’ve got to dial down everything in the first five hours of that day and try it again.”

RELATED: 5 Common Ironman Training Mistakes

Big Day Training workout: Round 2

• Swim 5000–6000 meters, with the last 2000 meters at a more challenging pace

• Quick break, change, recovery drink

• Bike 100 miles, or the equivalent of time you think you’ll be on the Ironman bike course

Tip: Start a little easier than your anticipated race pace, do the bulk of it around race pace, then finish up with the last third a little bit harder than race pace.

• Quick break, change, recovery drink

Tip: Try drinking a full quart of recovery drink before the 10k to fill up your gut. “It will slow you down,” Byrn says. “It will give you practice after a ton of exercise to figure out what to do when your gut is full. Guaranteed that it happens during the marathon. Sometimes your stomach is full, you feel lousy and you have to work through it. If you’ve done it in training, you won’t freak out on race day.”

• Run easy 10K

Byrn says you don’t have to get fanatical about your breaks in between, but to get the lesson from the session, keep them relatively short. Good luck!