The Four Pillars


This series originated with discussions on why I am able to put together a decent Ironman race when everyone finishing around me can absolutely crush me over shorter distances. It’s also been heavily influenced by the philosophy of my coaches (Hellemans, Molina and Friel), my athlete buddies (mainly the Swedes Doodes) and articles/books that I’ve read. I’d like to thank my buddies but accept full responsibility for the contents here.

Probably the best article that I have read on successful training is a simple piece that covered Mark Allen’s advice for lifetime fitness (Outside Magazine, February 1998, p 41-50). There is a lot of good advice in there and I recommend it for any athlete.


In this article, I am going to lay out my thoughts on the most critical factor for success for Ironman racing. In reading many of the publications and surfing the internet, I can see that there is a lot of interest in high intensity training. My experience with coaching and my own racing has led me to believe that, while scientifically interesting, high intensity training is not particularly useful for the majority of Ironman athletes.


Let’s start with a review of the Four Pillars of Ironman Success:

  • Nutrition – I covered this in an earlier series of articles and will explain my view on why it is essential for Ironman racing.
  • Strength – Also covered earlier. Strength training enhances your metabolic rate, economy and muscular endurance. It’s also a key limiter for many novice, female and veteran athletes.
  • Economy – The energy cost of holding any given speed. Economy is enhanced, to a greater and lesser degree, by just about any form of training (so long as you hold good form). There are many ways to improve economy and I’ll discuss my views on why economy is important.
  • Aerobic Threshold Endurance – The critical success factor for Ironman performance and the main topic of this series.
I was reading an article written by a buddy of mine about his recent experience training with a group of pros. Like me, his first impression when training with elites was how fast they go. The next time you are watching a race or training with elites, try to avoid getting caught up in the speed. Simply watch them move. I watched a lot of athletes move last week in Kona. If you do this then you can very quickly spot the real players.

I want you to notice three things – comfort, relaxation and smoothness. The thing that truly amazes me when I watch an athlete like Cameron Brown race, is not “how fast he goes”, it’s “how smooth and relaxed he is when going fast”. Cam doesn’t look like he is going very fast but he’s really moving. That kind of speed comes from a very deep form of fitness and superior economy, at least that’s what his coach tells me.


What is Aerobic Threshold?

There are many different ways to determine training intensity zones (lactate testing – see Hellemans, best average time trial average heart rate and/or power – see Friel).

Personally, I think the easiest and most effective method is to apply subjective perception. Start training at an easy pace and slowly increase the intensity of your exercises. You can determine your aerobic threshold by noting the heart rate where you feel the first deepening of your breath. This deepening is caused by your body increasing its demand for oxygen to metabolize an increase in blood lactate.

The point of deepening is the bottom range of your aerobic zone. The top of your aerobic zone can be estimated by simply adding 10 beats per minute to the bottom figure. I’ve done a lot of testing over the years and this method seems to work just fine for Ironman training.


Why Aerobic Threshold?

When I first started training for Ironman my goal was to constantly drive my lactate threshold pace upwards. I figured that if my top end speed increased then my Ironman times would fall. This is what I call a top down approach to fitness. It is what the majority of athletes believe will lead to success. We’ve all heard the phrase, “train slow, race slow”. My view is that a top down approach neglects the two most critical elements of successful Ironman racing.

  • Endurance – it doesn’t matter who you are, you will not be able to maintain a high intensity for an entire Ironman race (although that doesn’t stop us from trying from time to time).
  • Race pace – most athletes race Ironman in their aerobic zone or LOWER.
Take these two points together and, my view, is that the key variables to optimize are aerobic threshold endurance (first); and then aerobic threshold pace (second).

Let me illustrate with an example of two athletes. Let’s assume that the first athlete is me and the second athlete is a mid pack IM finisher (call him "Buddy"). For Ironman performance, what are the key physiological differences between Buddy and me?

Aerobic threshold endurance – I will last longer and travel faster at aerobic threshold. When I was an Ultrarunner, I could last 12 hours at aerobic threshold. Buddy’s been endurance training for a while – let's say that he lasts seven hours at aerobic threshold. Frankly, I think that seven is generous – as we all know – a one-hour open water swim followed by a six-hour aerobic ride is one tough session. For the average IM athlete, my estimate is that we are looking at aerobic endurance in the six to ten hour range.

Body composition -- Buddy is carrying more excess baggage than me. This reduces his economy and slows him down at all levels of intensity.

The key challenge facing Buddy is how to extend his aerobic threshold endurance beyond his estimated race duration but, there is a catch. No matter how fit Buddy gets, he's going to have a tough time taking his aerobic endurance much beyond 10 to 12 hours (remember that the average finishing time at most Ironman races is 12 to 13 hours). This endurance estimate is based on my experience coaching and racing ultra events (Ironman, Ultra marathons, Mountaineering). This is where body composition comes into play because our economy/pace per watt/heart beat/RPE all are enhanced from improved body composition. Add the recovery/long term health benefits and nutrition becomes even more mission critical for the athletes in the back half of the field.

Implications and ideas for you:

  • Novices should spend nearly all their time enhancing economy and building aerobic threshold endurance.
  • Experienced athletes with race times that are significantly longer than their aerobic threshold endurance must address their body composition. For the back half of the field, this is the most rapid way to achieve significant gains in economy, and therefore, aerobic threshold pace.
  • If your aerobic threshold endurance is equal to or less than your anticipated race duration then spending ANY time above aerobic threshold in a race will prove costly. Eventually, you will find that you are unable to get your heart rate up. You will have simply taken yourself beyond your aerobic threshold endurance. With my own IM racing, this happens in the 10- to 11-hour range. This seems to be an explanation for why many well-nourished and well-hydrated athletes simply run out of gas. I think this is the most common form of “bonking” and it has nothing to do with race nutrition or hydration.


Practical Application

So how best to apply the Four Pillars? I would recommend the following tips for building your week:

  • Schedule two strength sessions.
  • Schedule at least three sessions of each sport – if you stick to training in your aerobic zone then elite and experienced athletes can tolerate four to six sessions per sport per week.
  • Gradually push your endurance envelope while improving your sport specific skills/economy.
  • As you get faster, train longer and more frequently rather than more intensely.
Remember that getting tired is the point of training. Fatigue yourself with aerobic training. Once you are tired use total rest (best for novices) and active recovery/skills work (best for elites and experienced athletes) for restoration purposes.

You need to be quite fit to handle a lot of aerobic volume. It sounds easy but heading out and riding a focused six hours in your aerobic zone is one heck of a tough session. Many athletes will need to start with primarily easy pace and moderate amounts of aerobic work inserted into their endurance sessions.


A Word on Swimming

Haydn does a fantastic job of offering swim tips for XTri. Here are some key points to remember with your training.

Most of us don’t wear heart rate monitors in the pool. So how can you estimate your aerobic zone? Based on my experience, it is likely to be the pace that is about seven seconds slower per 100 meters than your 1,000-meters best average time trial pace. This should be a comfortable bilateral (three stroke breathing) pace. If you cannot hold this pace swimming bilaterally then you would be best to work on swimming technique rather than swimming aerobic endurance.

As a reminder, the short intervals and high lactate work that many swim coaches (and athletes) prefer is most likely sub-optimal for developing your aerobic endurance. I have made my greatest gains in swimming from focusing on threshold and sub-threshold endurance and strength work. Moderate amounts of faster work are beneficial for strong swimmers, but you rarely want to be generating very high levels of lactate.

For those of you who are 60-minute IM swimmers or slower – keep the pace down. Why? Because technique is near impossible to hold under high lactate levels (be honest with yourself!). Absolutely perfect swimming in your aerobic zone is best. Until you are sub-1:15 -- absolutely perfect easy paced swimming with moderate amounts of steady is the way to go.


What about my speed?

I can hear many of you wondering, “how am I going to get fast if I only tool around in my aerobic zone”? My athletes express this all the time during the winter and spring. I hate to break it to you but we aren’t fast. Macca and Siri are fast, you and me, we simply aren’t that quick.

Have a look at the finishing times for the people at the top of your age group or even the pros. Running a seven-minute mile is not fast (to a runner), running 26.2 of them after a swim and bike – that’s IronSpeed and is what we are seeking to build. If we sacrifice our aerobic training in an effort to chip away at our 5K run times then we are fooling ourselves. Solid Ironman performance is simply about not slowing down – in order to achieve this goal we need to be aerobically fit, economical and strong.

While “speedwork” (anaerobic endurance sessions) is not recommended, I strongly recommend that you do quickness training. These sessions include strides, spin-ups and other technique drills that will build quickness/economy while not generating high levels of lactate (See Friel).


But I’m going so slow…

When you start training this way, you are going to be moving very slowly. I’m a reasonable runner and my aerobic pace starts each season very slow. I would encourage you to keep the faith with your swim, bike and run sessions. If you stick with it then your aerobic endurance and aerobic pace will increase. Remember that you are training for a very long day of aerobic exercise.

As your dedication pays off and you start to see the results, you will have the urge to test yourself. My recommendation is that you test your endurance, not your speed. Aim for the following goal sessions:

  • Swim – One and a quarter hours, long course (50-meter pool), continuous aerobic swimming with three stroke breathing
  • Bike – Six hours, continuous aerobic riding
  • Run – Two and a half hours, continuous aerobic running
Once you can comfortably complete these sessions in a normal training week, you will be well on your way towards a solid Ironman time. Again, these sessions may sound easy (for the experienced) but the focus and fitness required to hold your aerobic zone for an extended period of time will surprise you.

What next? I’d recommend that you build your skills, strength and aerobic endurance for the next four months. If you feel like it then do one or two shorter races a month to keep yourself mentally fresh and to have a focus for your training. Come March, you will be in Tour de France shape and I’ll tell you what comes next.

See you at the races,



For more information on training intensity zones and a good explanation of lactate testing protocols and data interpretation, pick up a copy of John Hellemans’ Training Intensity Handbook. The handbook explains the aerobic and lactate threshold in detail, how to find your own individual training intensity zones and the reasoning behind it. Available from Active Health QE2 for US$20, which includes postage. For more information contact, John Hellemans, Active Health QE2, PO Box 27145, Christchurch, New Zealand, Payment can be made by Credit Card, NZD Bank Draft (NZ$40 payable to Active Health QE2) or US$ check (US$20 payable to Gordon Byrn).

For more information on effective triathlon training techniques, pick up a copy of Joe Friel’s Triathlete’s Training Bible. Joe and I will have a new book out in the spring that is specifically aimed at applying our training principles to ironman-distance racing. Our working title is Triathlon, Going Long.