The Triathlete Blueprint Newsletter #118-From 70.3 to 140.6: What Destroys Most Triathletes on Full Distance

Yan Busset
Aug 2
6 min read

Updated: Aug 5

Read time: 5min.

By Coach Yan Busset

Going from 70.3 to Full Distance: What You Really Need to Know

You’ve done a 70.3 and you’re now thinking about stepping up to the full Ironman distance. That’s great. It’s an exciting challenge and a logical next step for many triathletes. But let’s be clear from the start: two 70.3 races do not equal a full. The full distance is not just “twice as long.” It’s a different beast altogether, with its own rules and demands. Copy-pasting your half-distance strategy simply won’t work.

So here’s what you really need to know before going long.

Pacing: You Can’t Get Away With It Anymore

In a 70.3, especially for an experienced age grouper, you can still get away with some pacing mistakes. You might go a bit hard on the bike and still survive the run. Not ideal, but manageable.

In a full Ironman, that margin disappears. You don’t get second chances. If you pace it wrong, you will pay for it, and the run will be a disaster. The intensities must stay low, fully aerobic. No flirting with tempo or threshold just because you “feel good.” If you feel like you’re truly racing during a full, that’s probably a red flag. You’re going too fast. It’s a long game. Burn too many matches early, and you’ll have nothing left when it matters most.

Nutrition: As Important As Pacing

Nutrition is not just a detail. On full distance, it’s as critical as pacing. Think of Ironman as Swim, Bike, Run... and Eat. You’re not just racing. You’re fueling a long-duration effort.

What works for you in a 70.3 might not work over the much longer time frame of a full. Products that feel great early on may become sickeningly sweet after ten hours. Carb quantities that were fine at 4–5 hours might not be tolerable anymore. You may hit taste fatigue or have trouble absorbing carbs in the same form as before.

That’s why testing is essential. Test your nutrition plan. Have alternatives—saltier or more neutral flavors, different textures. And be careful with copying what the pros are doing. Sure, they’re pushing 100+ grams of carbs per hour. But they’re also finishing in under 8 hours. If you’re going to be out there for 12 to 16 hours, your gut will not handle the same intake. You need your own plan. One that works for your pace, your stomach, and your race duration.

Every Little Detail Matters

On shorter races, small discomforts are tolerable. A tri suit that rubs a little. Bike shoes that pinch slightly. A position on the bike that’s aggressive but just about manageable.

On full distance, everything gets amplified. That tiny chafe will become a raw wound. That bike position that felt “okay” over 90 km? It might turn into a torture rack over 180. And those slightly-too-new running shoes? They might cost you your toenails, your race, or both.

So test everything. Not just in training, but in race-like conditions and durations. No wishful thinking. Be systematic. Validate your gear choices. Stick to the golden rule: no new things on race day.

Comfort matters. And on the bike especially, remember this: the most aerodynamic position isn’t the lowest one you can hold for 20 minutes. It’s the fastest position you can hold comfortably for the full 180 km. If you start flat and end up sitting up like a tourist halfway through, you’re not aero anymore.

It’s Not Just About Endurance. It’s About Strength.

Of course you’ll need longer sessions in training. Longer rides. Long runs. That’s a given. But here’s the catch: endurance isn’t always the main limiter in full distance. Often, it’s strength.

The longer the race, the more important your strength and conditioning becomes. In the final part of the marathon, it’s not just cardio. It’s your body’s ability to hold form. To keep running with good posture. To keep moving without breaking down.

And when that strength is missing? That’s when you start to walk. That’s when you start to hurt in places that shouldn’t hurt. It’s not always a lack of endurance. It’s often a lack of strength.

That’s why strength training matters. At least two sessions per week. Basic movements. Heavy weights. Consistency. That’s what will keep you moving when it gets tough.

Volume Is Important, But Only If You Can Absorb It

Yes, you’ll need more volume to prepare for a full Ironman. But more volume doesn’t mean better results unless you can actually absorb it.

Be smart. Monitor your recovery. Check how you sleep. How your mood/feel is. How your HRV and your weight are behaving. These are signs of how well you’re coping with your training load. There’s no point stacking up more hours if your body can’t recover from them.

Age groupers aren’t pros. We have jobs. Families. Limits. There’s only so much volume we can handle. The key is consistency over time, not a sudden spike in hours. Build gradually. Stay consistent. That’s where the real progress lies.

Burnout and overuse injuries happen when you rush the build-up. When you think volume is the only solution. It’s not.

Dark Moments Will Come. Be Ready.

This isn’t a question of “if.” It’s a question of “when.” On a full Ironman, the dark moments will show up. Everyone has them. You might suddenly feel like your back is locking up. Or that your energy has vanished. Or that your race is slipping away.

That’s normal. It happens to everyone. The key is not to panic.

Slow down. Eat. Drink. Regroup. Give it five minutes. Ten. Twenty. It will pass. It always does. The body is more resilient than we think.

When you’re in the middle of a dark patch, it feels like the race is over. That you’ll never reach the finish line. But once you get through it, it’s like it never happened. You’ll find energy again.

The key is to expect it. Be mentally prepared. As Winston Churchill said: “If you’re going through hell, keep going.”

Final Thoughts

Stepping up to full distance is exciting. It’s a powerful, personal journey. But don’t treat it like a longer version of your last 70.3. It’s not. It’s something else.

And also, you don’t have to do a full Ironman to be a “real” triathlete. You can have a lifetime of challenge and satisfaction racing sprint, Olympic, or 70.3 distances. It’s not a ladder you need to climb to be legitimate. Usain Bolt was not running marathons. Doesn’t make him less of a runner.

Find the distance that suits you. The one that gives you joy. The one that fits your lifestyle. And work on being the best version of yourself at that distance.

That being said, do try them all. Test different formats. Try a full Ironman. It’s a unique experience, and it teaches you a lot. But once you’ve done one, don’t fall into the trap of thinking you can’t go back. I often hear people say, “I won’t do a sprint or an Olympic anymore, I’ve already done a full.” That doesn’t make sense to me. Being a well-rounded athlete means mastering different formats, different intensities, different race dynamics.

Many of my athletes nowadays race fewer full Ironmans and focus more on 70.3s because it fits better with their life. And that’s totally fine. You can have a lot of fun across all distances.

Avoid the mindset that one format is “better” than another. There’s no hierarchy. There’s just you, your goals, and the lifestyle you want to live.

Check out my Youtube Channel: