How to train for ironman

How to train for ironman

Have you contemplated the challenge of doing an IRONMAN, but the thought of giving up all your free time for training holds you back? Perhaps, you are an experienced triathlete, having completed sprint and Olympic-distance races. Life, however, has your clock in a stranglehold, and training time is at a premium.

I designed a training plan for people who don’t have much time but simply want to complete the event without illness or injury. It is certainly not for beginner athletes, but for beginning IRONMAN athletes. Training covers 13 weeks and culminates in completing your first 140.6-distance race in about 12 to 14 hours. Your largest training week will encompass about 13 hours, while other weeks are less.

Can You Do It?

Before beginning this plan, you are capable of swimming three times per week for an hour per session. You estimate you could hold at least a two-minute-per-100-yards pace for the 2.4-mile swim (total swim time of about 1 hour, 20 minutes, give or take).

You can bike comfortably for an hour and a half or so. With training, you’re confident you could average between 15 and 16 mph for 112 miles (total bike time between 6:15 and 7:30).

Right now, you’re capable of doing a long run in the 1:15 to 1:30 range. You think you could manage a marathon pace of 10- to 11-minute miles (total run time between 4:15 and 5:00). Up to this point, you’ve been training around 8 to 10 hours each week without major problems.

Due to a long list of commitments, weekday training is fairly light. However, weekends are open for long training hours. You realize taking at least one day off from training each week keeps you healthy and in good spirits.

If this athlete profile fits you, your estimated completion time for an IRONMAN is between 12 and 14 hours. This projection still allows for a three-hour buffer to complete the race under the maximum 17 hours permitted.

Workout Details

Training for an IRONMAN requires preparation. You’ll need a plan that maps out what sport to do each day, for how long and what type of workout to do.

I’ve started off with a one-hour swim and a 30-minute run. The goal of the swim is to work on technique and neuromuscular training while keeping your intensity low, thus concentrating on form over speed. The run is done at a steady pace for aerobic maintenance, keeping your heart rate in a designated zone.

By integrating training intensities and heart-rate zones into your IRONMAN preparation, you’ll have a good indicator of your conditioning, and rest and stress levels. A more thorough explanation can be found here. We’ll use a heart-rate monitor to designate the intensity for cycling and running workouts. This intensity is like the tachometer of your car; it tells you the pace of the engine. Keep in mind that heart rate can be influenced by fatigue, heat, hydration and other factors, so it is not a direct measurement of pace.

The Ironman triathlon, consisting of a 2.4-mile swim, a 112-mile bike and a 26.2-mile run, is among the most difficult organized athletic challenges in the world. Competing in and finishing the Ironman represents an incredible achievement in endurance, both mental and physical. Even if you don’t end up competing in an Ironman, the training regimen you’ll adhere to along the way will whip you into the best shape of your life and help you to decide whether the Ironman is a realistic goal.

Step 1

Achieve equal competence in swimming, cycling and running. Each leg of the Ironman is so long and so grueling that it will be difficult or even impossible to finish if you assume that you can make up for poor swimming technique just because you’re an excellent and experienced marathon runner, for example. Hire a coach to teach you the proper techniques for one of the three disciplines if you lack experience in it.

Step 2

Participate in several Olympic-distance or standard-distance triathlons, which include a .93-mile swim, 25-mile bike and 6.2-mile run. You should be finishing near the top of your age group in these events before moving on to longer triathlons and eventually the Ironman.

Step 3

Participate in a Half Ironman, also known as a long-course triathlon. This includes a 1.2-mile swim, a 56-mile bike and a 13.1-mile run. Remember that a full Ironman is exactly twice as long as a long-course triathlon, so an inability to complete a Half Ironman would be a sure sign that you’re unprepared for the Ironman.

Step 4

Create a training schedule that has you working out at least five to six days per week. The initial weeks of a typical schedule might have you swimming 1,000 yards and biking 20 miles on Monday, swimming 1,250 yards and running 45 minutes on Tuesday, biking 25 miles on Wednesday, repeating Tuesday’s workout on Thursday, resting on Friday, running 55 minutes on Saturday and biking 30 miles on Sunday.

Step 5

Increase the length of your workouts with each subsequent week of your training schedule. Plan on training for at least 18 weeks leading up to the Ironman event itself.

You can prepare for a successful Ironman triathlon with a program that has an average training volume of only 12 hours per week and a briefly-maintained peak training volume of 16 hours.

You can prepare for a successful Ironman triathlon with a program that has an average training volume of only 12 hours per week and a briefly-maintained peak training volume of 16 hours. And by “successful” I don’t mean finishing alive. I mean covering the distance as fast as your genetic potential allows. In fact, I believe that many triathletes can race a faster Ironman by following a well-constructed 12-hours-a-week program than they could with a higher-volume approach.

There are five specific reasons a minimalist approach to Ironman training can work just as well as, if not better than, a higher-volume approach.

1. Swimming performance is all about technique, not fitness.

Very little improvement in swimming performance comes from building swim fitness through hours of training. Almost all swimming improvement comes from technique refinements that often occur instantaneously. You should swim-train for an Ironman in a way that encourages and accelerates technique refinements instead of in a way that concentrates on building fitness. Get one-on-one stroke coaching from a qualified swim coach, study freestyle technique, fiddle with your stroke, use swim aids that encourage technique development and perform technique drills for body position, rotation, efficient breathing, a strong pull and efficient kicking. Use intervals and sustained swimming primarily to ingrain technique and secondarily to develop fitness.

2. The swim just isn’t that important.

To complete the swim leg of a Hawaii Ironman as fast as your inner talent allows, you would have to train in the pool two hours a day, six days a week, or thereabouts. That’s what it would take to shave off every second possible. But the swim accounts for only about 10 percent of the time it takes to complete an Ironman. And you can get at least 90 percent of the way toward your fastest possible Ironman swim split by swimming just one hour a day, three times per week. So why not do that?

3. Cycling fitness crosses over well to running.

When I trained for my first Ironman in 2002, my run training was severely compromised due to injury. My race took place in mid-September. Through July I averaged just 15 miles of running per week. Not until five weeks before the race was I able to do my first “long” run: a 12-miler. I squeezed in a 16-miler and a lone 20-miler before race day.

Despite these limitations, I was able to run a 3:23 marathon at Ironman Wisconsin—not as fast as I could have run with better training, but faster than all but 42 other participants in the race nevertheless. The reason, I realized, was that my excellent cycling fitness carried me through the run.

You can count on the fitness crossover from cycling to running to trim back the amount of run training you do in preparing for an Ironman. One long run, one high-intensity run and a moderate, steady base run (to which more advanced athlete’s can add a threshold progression or a sprinkling of fartlek speed intervals) each week will suffice. You may also do one- or two-mile transition runs after bike workouts to prepare for the specific challenge of running off the bike.

4. High-intensity indoor cycling is time-efficient and effective.

Cycling predominantly indoors can be an effective means to develop a higher level of cycling fitness with a substantially lesser time commitment to training than cycling exclusively outside. Riding indoors requires less set-up time and entails fewer stops than outdoor riding. It is also more intense—heart rates are always higher on an indoor trainer because there is no momentum and there are no downhills. Finally, the indoor cycling environment is more controlled and more conducive to high-intensity riding.

There is a small trend of predominantly indoor bike training at the top levels of triathlon these days. Andy Potts, the 2007 Ironman 70.3 World Champion, typically rides outdoors only once a week. His five or six other rides are indoor workouts featuring lots of lung-busting interval and threshold efforts and lasting only 45 minutes each, on average. Tyler Stewart, who has the fastest women’s Ironman bike split in history (4:47:59 at Ironman Florida in 2007), gets most of her bike training in the form of 90-minute interval-based indoor workouts that she teaches for other triathletes and cyclists. Like Potts, she rides outdoors just once weekly and she completes only a handful of rides longer than four hours before racing an Ironman.

I’ve recently adopted a similar approach to my Ironman bike training, and with excellent results so far. Each week I perform five rides on a CycleOps 300PT indoor trainer. Each of these rides is 30 to 45 minutes long and two feature very challenging high-intensity work. On Saturdays I hop on my Kestrel Airfoil and ride long. My power numbers are as high as they have ever been, but my time commitment to bike training is much smaller than it has been in the past. Try it and you’ll see.

5. A dozen century training rides won’t give you much more cycling endurance than two or three.

I just mentioned that the fastest female Ironman cyclist in history completes only a handful of four-plus-hour rides before competing in an Ironman. This practice is in contrast to that of many competitive Ironman triathletes, who start doing multi-hour rides months before race day. But Tyler Stewart’s success proves what common sense would suggest: that it’s simply not necessary to do a ton of long rides that are close to the Ironman bike leg distance to build the cycling endurance needed for a successful Ironman.

If you build a solid foundation of cycling fitness by doing a lot of the hard threshold and interval training that so many athletes avoid, and by regularly performing fairly aggressive long rides in the 2.5-3.5-hour range, you can easily extend the range of your pedaling power to encompass the full Ironman distance by incrementally increasing the distance of your weekly long ride from, say, 60 miles to 100 miles through the last eight weeks of your training preceding your taper. With this approach you will cultivate adequate endurance without doing so at the expense of pure power, and with minimal risk of burning out, and, not least importantly, without wasting a second of your valuable time.

If you’ve been bitten by the triathlon bug, chances are you’ll want to go long and race your first half- and full-distance IM at some point. If this year is the year, here are a few tips to get you there.

Train Every Day

How to train for ironman

It takes a minimum of 13 hours of training per week to get in shape for an IRONMAN race. That means you’ll be training almost every day of the week. After all, you not only have to swim, bike and run during the race, but you have to beat the cutoff times. Participants in competing in the half or full IRONMAN events will be pulled from the course if they’re unable to finish each leg of the event in the set amount of time. So, get ready to spend some serious time in the pool, on the bike and in your running shoes.

Don’t Fake It

How to train for ironman

To some small extent, you can fake the training for both an IRONMAN and half-distance race. In other words, you can finish both of these race distances without completely putting in the time to train, but you’ll hate the race.

There are few things more miserable in life than spending 17 hours on an IRONMAN course, hating every painful swim stroke, bike pedal and running step. Sure, there are amateur athletes who’ve finished without putting in the hard work, but they just spent over $500 on the entry for a day of self-inflicted pain.

The Fourth IRONMAN Discipline

How to train for ironman

You probably know that a triathlon of any length consists of a swim, bike and run, but to succeed at the half and full distance you’ll have to learn a fourth discipline: nutrition. Unlike the sprint or Olympic distance triathlon, the half and full IM becomes about how fast you can swim, bike and run, and just as importantly, how you can take in enough calories to keep from bonking. Unless you are a pro, it will take at least 10 hours to complete an IRONMAN. In that time, it will be impossible for you to take in more calories than you’ll burn.

The human body just isn’t designed to take in more than several hundred calories per hour during intense exercise, while at the same time burning four of five times that amount. The trick is to figure out how your body reacts to prolonged stress and how to best compensate for this intense and long exercise without bonking. A successful IRONMAN triathlete has spent considerable time honing their nutrition regimen prior to a race. And as odd as it may sound, when you step up to the longer distance races be prepared to feel sick. Gastrointestinal discomfort is common in athletes participating in the IM distance.

Avoid Injury

How to train for ironman

It’s the No. 1 secret to moving from shorter triathlons to the half or full IRONMAN distance. That means staying healthy and injury-free throughout your training. Unfortunately, the long IRONMAN training hours required to prepare for the event make it difficult to stay injury free. It’s all too easy and common to blow out a shoulder swimming in the pool, or develop a case of plantar fasciitis while ramping up for the marathon. Bike accidents are always a constant danger.

An amateur triathlete who wants to attempt an IRONMAN should find a coach or online IRONMAN training plan and stick with it. Coaches or training plans help minimize the risk of injury and fatigue. It may cost more in the short term, but when compared to the cost of surgery it is money well spent.

Running a marathon after swimming for 2.4 miles and biking 112 miles is very different than running an open marathon. Learn how to set your zones correctly and use pacing strategies to train correctly.

While a marathon is 26.2 miles, how you approach it depends on if you are solely running, or if you have a swim and bike beforehand. Two of the most common questions are, “How do you compare an open marathon to an IRONMAN marathon” and “What does my run training for the IRONMAN marathon need to look like?” Both are great questions and essential for putting together a training program to accomplish your goals on race day.

Using the Right Metrics

The first key is to make sure that your running pace is based around a physiological value, such as Lactate Threshold (LT). Heart rate (HR) is not an output metric, it’s an input metric. Basing run training on HR (while actually running, as in looking at the HRM) is better than nothing, but it’s not going to put you in the best position possible when training and on race day. Remember, HR is subject to a lot of variable such as temperature, hydration, mood, nutrition, etc… which can lead to too much variability to use accurately in training as anything other than a guide.

Using your running velocity at LT (vLT) to determine running zone paces (min/mi) is an OUTPUT metric, meaning it’s what you’re putting out while training and racing. It’s the equivalent of using power on the bike.

Setting Training Zones

Lets use two sample athletes, the first having run their IRONMAN marathon in 3:15 and the second who ran 3:44. I typically assume that an athlete who runs an IM marathon under 4 hours can safely subtract 20 minutes and get their open marathon time. For athletes over the 4 hour mark, it might get up closer to 30 minutes.

The table below is calculated from the Training Peaks Pace/Speed Zone calculator using Joe Friel for Running. It shows all the relevant data to include estimated vLT1 and training zones based off those.

The training for each of these athletes needs to be based off their “open” marathon time and associated vLT, not their IRONMAN marathon time. If we use vLT, our training zones will be far more accurate since there are now physiological variables attached to them.

The 3:15 IM marathon pace of 7:27 is in middle of zone 2 (7:05-8:01) for zones that are set based on the 2:55 marathon time and associated vLT.

The 3:44 IM marathon pace of 8:33 is in middle of zone 2 (8:10-9:15) for zones that are set based on the 3:24 marathon time and associated vLT.

Intensity of Long Run Training

Next is how fast to pace your long run. Remember the main reasons for a long run are time on your feet and building endurance. The physiological benefits we are seeking include an increased stroke volume, increased mitochondrial density and capillarization as well as strengthening the connective tissue in the lower limbs. These benefits occur most effectively in zones 1 and 2, when you’re between 60-75% of max HR (look after the run) or 55-75% of VO2max.

As you increase your intensity up into the “tempo” or zone 3 range, you are starting to stress different energy systems. Adding some zone 3 work into longer runs is a very wise strategy, especially for someone who is running around 3:30 or less for a marathon and/or if performance is a goal. Running for 2 hours at that intensity is doable, but the muscular damage and extended recovery might not be worth it.

Tempo runs by themselves can reach the 90-minute range (with warm up and cool down) and provide some tremendous benefits! The question you need to answer, do you want quality or quantity?

Here are some sample “tempo” workouts, which can be converted into longer runs by adding to the warm up and cool down.

Steady Tempo Run

  • Warm Up: 15 minutes in zone 2 (use the full zone)
  • Main Set: 40-60 minutes in zone 3
  • Cool Down: 15 minutes in zone 2 (using the full zone again)

If the second athlete in the previous example got an hour in at the slower end of zone 3, that would be close to 7.5 very high quality miles.

Tempo Intervals

  • Warm Up: 15 minutes in zone 2 (use the full zone)
  • Main Set: 3×20 minutes in zone 3 with a short recovery
  • Cool Down: 15 minutes in zone 2 (using the full zone again)

This adds up to the same basic numbers above, but I would argue, you will get a higher quality of running, more time in the faster end of zone 3, if you break that time up and add in a short recovery.

Threshold Repeats

  • Warm Up: 15-20 minutes in zone 2 (use the full zone)
  • Main Set: 2-4 x 2-miles or 6-8 x1-mile in zone 4 with a 4’/3’/2’ easy jog recovery
  • Cool Down: 15-20 minutes in zone 2 (using the full zone again)

This workout will add in some more high-end running that is marathon specific.

Pacing for an IRONMAN Marathon

Now that we have established the differences between an IRONMAN marathon and an open marathon, as well as the proper pacing for your run training, we can look more closely at pacing during the IRONMAN. The pacing for race day should be based off your projected IRONMAN marathon time, not your open marathon time.

In the examples above, the first athlete can run a 2:55 open marathon, but is looking at a 3:15 at IRONMAN. Their pacing needs to be selected based on the 3:15 time, which would put them between 7:52 and 8:54 min/mi. Looking at the second athlete, their proper pacing on race day should be between 8:56 and 10:06 min/mi. These running paces will put both athletes in zone 2, which is sustainable for an IRONMAN marathon.

If the athletes used the open marathon paces, they would ultimately end up in zones 3 and 4 based on the IRONMAN marathon goal time. The first athlete’s zone 2 would drop down to 7:05 to 8:01 min/mi, which puts them well into their IRONMAN-based zone 3 and even into the lower ends of zone 4. The same is true for the second athlete that is looking to run a 3:44 marathon.

Training for a marathon, either open or in an IRONMAN, requires a mix of endurance, strength and speed. By working with your pace rather than heart rate, and training to the specific needs of each event, you can reach your goal.

Kaustubh Radkar has participated in 28 Ironmans, the most by an Indian. He shares his secrets on how to train for this tough race

How to train for ironman

In March last year, Kaustubh Radkar finished his 25th Ironman in Taupo, New Zealand. He remembers his journey back home to Pune being an eerie experience. It was one of the last flights to arrive in India, before covid-19 brought the world to a standstill. In the next few weeks, it was clear that there weren’t going to be any competitions in the near future.



As things started looking up this year, Radkar, 39, had the opportunity to travel to Switzerland on work, and realised that he could race at Ironman Hamburg at the end of August. Since he had some more time, he also decided to sign up for Ironman Tallinn and Ironman Frankfurt before Hamburg.


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By the end of August, he had knocked off all three Ironmans in a span of 22 days, taking his tally of races to 28, the most by an Indian.

A seasoned competitor since 2008, Radkar had long been toying with the idea of racing at three Ironmans in the same month. So there were no second thoughts when the opportunity arose. “I’ve done two Ironmans each year since 2014 and in 2017, I finished four. I’ve always enjoyed racing, but there was never a competition element to it. It’s all about how I can handle my body to get to the finish line on race day. Finishing three was the perfect test for my physical and mental fitness,” he says.



The lockdown disrupted his training and that of his wards, who he trains as founder and head coach of of RadStrong , a customised training program for aspiring runners and triathletes. On the personal front, he had enough gym equipment at home to maintain a routine through the pandemic lockdowns. But he soon realised that many people he knew were struggling mentally to cope with the pandemic. He started leading online strength sessions and cycling workouts on a stationary indoor trainer to keep up their fitness levels, which in turn helped add minutes to his own routine.

“I did a lot of back-to-back, low intensity training, at times for 4-5 hours each day. The idea was to build the mental strength to keep pushing,” he says, adding, “Strength training is another aspect that is of prime importance but is often overlooked by most endurance runners and Ironman athletes. I had a solid routine going for me at home.”


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Once the lockdown was eased last year, Radkar started road running, logging a weekly mileage of 45-55km. The cycling was pushed to 100-120km each week. Radkar was a national level swimmer in his younger days, so when the pool was accessible, he would swim thrice a week, focussing on drills and techniques instead of distance swims. At other times, he would practice land drills to maintain strength.

“Swimming is my strength among the three disciplines. But the pools were closed for a long time, so the technique needed sharpening. I used therabands to work on strengthening specific muscles when I couldn’t swim,” he says.



What aided Radkar in devising a training schedule was his degree in exercise science and the certifications related to running and triathlons that he’s picked up over the few years. At RadStrong, he has designed his own web-based application through which he plans workouts in a scientific manner for his trainees. This understanding of data and performance has also benefited his own racing.

“My prime philosophy is that less is often enough and I design my workouts accordingly,” he says. The experience of having competed in different situations has also made him realise the significance of mental strength in endurance races. “One’s focus and attitude can have an impact on the race. The physical aspects of Ironman training are immense and most athletes take care of them. What they ignore is the mental side of it,” he says.



Radkar’s complemented his workouts with a balanced diet of around 2,800 calories of home-cooked food every day. The evening before the race, he’d checked on the bike, organise his gear and tuck into a hot meal packed with carbs and proteins, and sleep early. “Since I was competing after so long, I had to deal with race jitters this time around. But it all felt normal once the gun went off and I started the swim,” he says.

Muscle memory played a huge role during the first race. Though he hadn’t biked a distance of over 120km close to race day, he experienced no cramping due to muscle fatigue. It was no different on the swim sections.



“I didn’t have the yardage needed for a strong swim. What was interesting was that my swim time on all three races was 52 minutes, despite the varying degrees of effort. And to do it without much training on the first one was a good boost for my confidence,” he says.

In between the races, Radkar pushed his food intake to 3,000 calories and focussed on rest. He could pull off two 3km runs on consecutive days before Ironman Frankfurt, and spent a lot of time stretching and eating hearty meals. It was a similar routine before Hamburg, long walks and stretches, and a short run a day before the race. Only this time around, there was also the comfort of wholesome Indian food at his friends’ homes.



It was a fitting end to his diligence over the last year when he clocked the fastest of the three times in Hamburg. “The plan is to enjoy Ganapati festival with good food, friends and family. Next week onwards, it’s back to training,” he says.

How to train for ironman

The day after an Ironman race, hundreds – sometimes thousands – of athletes line up or go online to register for the next year’s race. That’s right, the race was asking people to commit a year in advance. In today’s last minute, just-in-time world, this is an anomaly. Undoubtedly, many of you don’t even know where you’re going next month, much less next year. But this advance scheduling is critical to a successful Ironman, because for most competitors—and especially the first-timers—training for Ironman is a 12-month physical and mental challenge.

Over the years of coaching and preparing athletes to be Ironman ready, I’ve seen people take three years to achieve their Ironman dream as they made the steady progression from runner or cyclist to multisport Ironman finisher. It can be a long haul, people. But that commitment, when it results in success, is also a huge part of the sport’s satisfaction. With that in mind, I wanted to share some of the key, high-level triathlon tips I and the other coaches at CTS have gleaned from decades of working with Ironman athletes.

Step 1: Choose a Goal Ironman Race Based on Your Real-World Training Schedule

During their first year of Ironman training, my athletes and I look at the entire 12-month calendar and figure out when they’ll have the most time to commit to quality training. Seasonal weather, daylight, family and work commitments and even pool access are all considered into this equation. Once we figure this out, only then will we look at the racing calendar for an IM to enter.

Case in point: An Ironman in late June works well for parents of school-aged children since the most intense and longest training blocks for the race will occur in the spring/late spring while the kids are in school full-time. And the beginning of summer break will dovetail with the athlete’s tapering period.

For others, summer races with their great weather and long days hold the most appeal. However, others, who live in stifling hot summer climates may choose early spring races to motivate themselves to train through the winter months and then ramp up training during the cool spring months. In the end, figure out when you have the most time to train long and hard for several months first, then find a race.

Bonus Tip: Give and Learn

If you don’t get into your local Ironman race this year, or the nearest race date doesn’t jive with your preferred race date, use the race as a learning opportunity. Become a volunteer. It’s a fantastic opportunity for you to scout the race—and if you’ve never done an Ironman, see what you’re in for. You’ll familiarize yourself with the logistics, course and transition layout, and pick up a motivational buzz from seeing the racers pass by.

Step 2: Make Your First Ironman a 2-year Journey

Before you sign up for the Ironman of your choice, you’ll want to develop a deep base of experience. And I’m not talking about ripping off an Olympic-distance triathlon and then tackling an Ironman. I’ve found more success in coaching athletes to the finish line of an Ironman if they work their way up to it over 2-3 years.

It takes time for the body to adapt to the new stresses of training without the risk of injury. With a 2-plus year plan, you can set up a steady progression from Olympic to half-Ironman to full Ironman that conditions your body—and your family and work colleagues—to your training regimen and schedule. Of course, some athletes may be able to go from reasonably fit to Ironman-ready in a year. But I urge you to think about your Ironman as a two-year process at least.

Step 3: Pace Your Triathlon Race Schedule To Grow Faster, Not Just Finish

Once you cross the finish line, don’t be surprised at how soon you start thinking about doing another Ironman. The emotional satisfaction is that powerful. My advice, be cautious. One Ironman in a year is difficult, two is very challenging, and three would require a pro- triathlete’s commitment to training and focus (although it can certainly be done, especially by very experienced triathletes).

Personally, I’ve found that athletes who strive for balance in their family, career, and training do best by committing to an Ironman every other year. The level of focus required during your Ironman years becomes easier to handle and understand when it’s balanced with a year of reduced training volume. During the alternate years, focus on 70.3 Ironman races and work on getting faster. That way, you’ll ideally enter your next Ironman build with the strength and speed to not just finish, but set a new PR.

How to train for ironman

What’s the Minimum Training Needed for a Full IRONMAN Triathlon

I’ve finished nine IRONMANs thus far in my triathlon career. All of my finishing times have hovered between the 8.5 and 9.5-hour marks. Now before assumptions are made, trust me when I say I’m not trying to gloat. After all the suffering and the tumultuous emotions experienced in these races, I simply cannot fathom how most athletes are out there hell-bent on finishing no matter what the cost – for 12, 13, even 17 hours!

I’ve said it before and I’ll say it again: these IRONMAN athletes are tougher than I’ll ever be. I know with certainty that the men and women pushing forward for that length of time are experiencing more pain longer than what I had to endure.

Speed is subjective. For someone like Tim O’Donnell, a 9-hour flat time at IRONMAN Arizona would be a disaster. When it comes to finishing an IRONMAN, what matters most is capability. Therefore, the answer to “What’s the Minimum Training Needed for a Full IRONMAN Triathlon?” is a bit nuanced.

For some, the answer pertains to simply finishing and nothing more than that – “How do I make it across that line before the cutoff time?” This is the end goal under the conditions and capabilities of their current physical state. For others, however, the minimum training needed will be relevant to a finishing time much faster than the 17-hour cutoff.

Yet for all triathletes, IRONMAN training and preparation is, at its lowest common denominator, intended to avoid the dreaded bonk. Therefore what you need is a projection of what you’re potentially capable of and then the ideal training to reach said potentiality.

In other words, if you’ve learned that it’s possible you could finish IRONMAN Canada in 14 hours, then what’s required to make that a reality?

Race Projections

First, let’s talk about how to know your IRONMAN capability. There is, of course, no entirely conclusive way to know your full iron triathlon potential until you actually complete one. However, there are surprisingly intelligent ways to project overall finishing time and splits based on your current athletic condition.

“Threshold capacity” is the key phrase here. What is your average threshold pace for one hour at an “all out effort” for swimming, cycling, and running respectively?

In the TriDot Training System, we refer to these numbers as “functional threshold,” and we quantify your average pace along with heart rate and power (if relevant) into a single numbered score known as the TriDot Score.

With your TriDot Score along with your physical characteristics, such as age, weight, time in the sport, etc., we’re able to project your capability of race time, with splits in each discipline, across a wide array of triathlon distances.

But let’s not get too far ahead of ourselves! Understand that your functional threshold capacities are usually found in short intense time trial tests. For example, we use a 5K run to determine your current running functional threshold. An IRONMAN marathon, on the other hand, is a lot longer than a 5K. So it’s important to note that your split estimation for the IRONMAN marathon is assuming that you’ve done the required stamina training leading up to the event. We’ll get to more of that in a minute.

Additionally, what’s really unique with how TriDot has implemented its data-driven system is that we can actually take your threshold capacity and measure it against any IRONMAN course due to the known data of each scheduled event. TriDot has actually created an entire site dedicated to this and it’s called IronIndex.

Iron Index uses your threshold and physical factor data along with known information about the terrain and climate of an IRONMAN course, the strength of the field based on past results, and your body mass variance to determine personalized finishing time and splits (and even potential age group placing).

IRONMAN Training

So now that we know how capable you are of finishing an IRONMAN triathlon before ever touching the race course, the next step is to actually train based on the knowledge of that projection.

An entire book could be written here (and has been many times before). But what’s good about knowing what you’re potentially capable of beforehand is that now we can be realistic about how much time you’re going to be spending in the swim, bike, and run respectively.

For example, let’s say your threshold capacity and physical factors tell us that your IRONMAN triathlon bike split will most likely be 6 hours and 25 minutes. This informs us of a couple truths. One, if your functional threshold on the bike doesn’t change, you will need to train on the bike in such a way so as to increase your stamina until you’re capable of cycling at an IRONMAN pace for 6.5 hours.

This generally means gradually increasing your longest bike session each week until that stamina goal is reached.

The other truth, however, is that if we increase your functional threshold we could be looking at a projected split of 6 hours. Under this new functional threshold you would actually be required to train less in order to reach the stamina goal (again gradually increasing longest bike sessions).

This is a major reason TriDot advocates power threshold training before stamina training. If we can increase your functional threshold early, before the major stamina training is required – and this will depend on your IRONMAN schedule timeline – then the volume of later training (and wear and tear on your body) will be less because you’ll be finishing faster!

TriDot’s “fast before far, strong before long” line of thinking is intended to not only be logical, but also to reduce the chance of injury and to give you more time to recover outside of triathlon training.

TRIDOT TAKEAWAY: The minimum training needed to finish a full IRONMAN triathlon depends on your race capability. With that knowledge, proper threshold and stamina training is implemented in order to match your projected goal most effectively.

TALK WITH TRIDOT: Do you know what your triathlon threshold capacities are? What minimum training do you need to do for the full IRONMAN triathlon?

JARED MILAM is a professional triathlete, TriDot coach, and member of the Tri4Him Pro Team. He has 16 years of competitive running experience and 11 years of competitive triathlon experience with a half Iron PR of 3:59 and a full Iron PR of 8:30. Coaching under the TriDot system since 2011, Jared loves working with aspiring triathletes of all ages and performance levels.