Anyone who has ever witnessed an Iron-distance event has certainly seen it. Perhaps many of you have even experienced it. Months and months of training, spent developing tremendous speed, only to utilize this speed by walking the final ten miles of the marathon, because the body has shut down, and utterly refused to move any faster. At QT2 Systems we call this phenomenon "System Failure" which I will cover in more detail in my next article. The Ironman is simply too long. Most athletes, aside from professional and top-level age-groupers have neither the time nor the physicality to train at the levels necessary to complete the Ironman, without some level of System Failure. We refer to the levels of training, required not to experience System Failure, as "Critical Volume".

These thoughts are the fundamental basis of the QT2 training principals as well as the Triathlon Calculator (www.triathloncalculator.com). As stated above, the Ironman race distance is too long for most age group athletes given the constraints in their life (i.e. family, work, etc.), which prevent adequate training. Because of this, many athletes come into Ironman having cut corners on training volume, in favor of more intense workouts. This short cut approach is typically a short cut to faster race times over shorter distances, as well as a short cut to injury and/or burnout and a long walk during the marathon. Below I will discuss what it takes to gain speed (or not lose speed), efficiently and safely for the long haul at the IM distance, from a training perspective. It should be noted that the "QT2 4 Part Race Performance System" addresses Training, Nutrition, Race Pacing, and Race Fueling. This writing only addresses the Training piece…Just 25% of the total picture.

Every athlete has a current speed potential (current short distance speed) based on their swim/bike/run paces at threshold. Based on these paces, one can get a good idea on how they might perform at different event distances, using fairly well defined relationships. For instance, there are many good calculators available on the web that will tell you what your marathon performance may be, based on your 5K time. These performance estimates, use a curve that defines how your pace changes relative to race distance. I call this curve a speed potential curve. However, what this method does not tell you is that in order to achieve this speed potential, at longer distances, you must have a certain amount of endurance training and/or experience given the event distance (what I call durability). Based on this concept, I believe there exists undeniable training volume thresholds that must be met prior to your event, in order to achieve that speed potential, as well as to have an enjoyable experience. These training volume thresholds, or critical volumes (as I like to call them) are defined in weekly training volumes, based on the following relationships for each sport:

Swim - 9/3 of the event distance, per week
Bike - 8/3 of the event distance, per week
Run - 7/3 of the event distance, per week

For single sport events like the marathon, I believe these volumes should be met for at least 5 weeks (preceding the taper) during the final 8 weeks of training for the event. For triathlon these volumes should be met for at least 2 weeks during training (ideally during your final build weeks), during the 6 weeks leading up to the event. The duration of meeting these volumes (2 weeks vs. 6 weeks) is less in triathlon, because of the cross training affect between the disciplines. Another factor that I have observed is that additional benefit can be realized on run performance by increasing bike volume up to 50% greater than those volumes specified above. This tactic is pretty elite stuff and should not be considered by folks who have not already met the other critical volumes, or feel that they have room to improve their pace at threshold (based on athlete specific limiters).

The critical volume factors should be used to determine how much volume to complete for your goal event. Typically when I lay out a multiple month plan leading into an event, I look at where the athlete's volume is currently and whether or not it will be safely possible to reach the critical volumes for the event, in time for the taper.

It should be noted that for elite athletes in the ITU scene, or who race at shorter distances, sometimes the best way to improve speed potential, after adding intensity, is to increase volume beyond what is required for durability. For most, this is not necessary, because intense workouts, on a weekly basis, are enough to elicit speed improvements, when combined with consistency.

Let's take a look at what this means for the most extreme example, Ironman. Have you ever wondered why the time gaps, on a percentage basis, between the pros and age group athletes are much greater in Ironman than Olympic distance racing? It's simply because most pro Ironman athletes are able to meet their critical volumes, while age groupers are not. The pros are able to maintain pace, while most age groupers significantly slow down at some point during the race. For example, if I wanted to be a top pro Ironman triathlete, I would want to meet the critical volumes for the event (and maybe add up to 50% to the bike volume):

Swim = 2.4 miles = 4220 yds x 9/3 = 12,660yds

Bike = 112 miles x 8/3 = 300 miles (up to 450 miles, once the volumes in the swim and run have been met)

Run = 26.2 x 7/3 = 60 miles

For a pro Ironman triathlete, this equates to about 3.5 hours of swimming, 17 hours of biking and, about 7 hours of running. This is a total of about 27.5 hours of training for the final build week before the race. Based on this, it is no surprise that you see elite Ironman triathletes training in the 30 hour range.

Sure, speed can be gained by shorting the critical volumes and doing more intense workouts to increase overall stress. However, a drastic increase in total race time is realized when an athlete "hits the wall" during a race due to inadequate durability, or race fueling. In addition, the chance of injury is drastically increased with this kind of short cut. I find it much more beneficial, and safe, to first meet the critical volumes, whenever possible, before adding any significant intensity.

Here is the simplest example of the concept for critical volume: You have a friend that you can beat at the 5k, a 15 mile bike ride and a 400 TT in the pool, even though that friend trains much more than you. However, when you go to the half iron distance he successfully beats you by 10 minutes. This is where critical volume comes in. He has gained the durability (through volume) to extend his speed potentials to longer race distances (even though you may have better speed potential curves). Critical volume suggests how much training is required to gain the majority of the durability required to meet your speed potential for various race distances. At long distance races, this lack of durability is the major determiner of time loss for most people (95% of age groupers in IM…again, the race is too long). Meet critical volume, and you will beat most people around your speed potential, even though they may be faster than you at short distance racing. This is even more the case in IM racing where almost no one, save for some in the pro wave, meet critical volume. Athletes without the durability required for the distance become too fatigued, peripherally, to be able to continuously stimulate there core systems (cardiac/O2 delivery) throughout the day. This is regardless of how talented they are with their speed potential (core system).

A lot of people misunderstand my critical volume concept to mean that you must do these huge training mileages to do well in IM. That is not what critical volume is about. Below is a figure that I have developed to further illustrate my point. This is a speed potential curve for the run. On the left you can see that an athlete's 5k time is what anchors the speed potential curve (shifts it up and down). This is a good indicator of speed potential, because the distance is short enough to not have durability be a limiter. Believe it or not, these curves are fairly constant from individual to individual. That is, if two people have the same 5k time and both meet critical volume for a half marathon, they will race very closely over a half-marathon. In the example below, this athlete trains enough to meet critical volume for the half marathon (7/3 x 13.1 = 30 miles per week). Based on that, he will be able to meet his 5k determined speed potential curve for all race distances up to and including the half marathon. If he try's to race a distance longer than that, his speed follows the dotted line which indicates his performance has been limited by a lack of durability (unable to meet speed potential curve).



The reason why so many age groupers race IM so much more slowly than they may expect is due to this occurrence (if not due to race pacing and/or race fueling). One thing to note on the figure is that an improvement in your speed potential curve even after years of training is not nearly worth the benefit you get from meeting critical volume for your race distance. Time lost by lack of durability can be huge in comparison to minor differences in speed potential (that can take years to achieve). This is why the QT2 training methods focus on meeting critical volume, or getting as close as possible, before anything else. There is no need to dabble in extra speed work, or other risky training methods that may increase speed potential, until you are able to meet, or get very close (at least 2/3) to critical volume. Instead, we focus on the details such as nutrition and rest, which are the support structures that allow one to meet critical volume, without becoming sidelined due to sickness/injury. As shown in the figure, the benefit of meeting the durability required for your race distance is much more beneficial than any improvements in speed potential.

Additional training beyond critical volume does not typically do much but decrease speed potential due to inadequate recovery between key workouts, elevated catabolic hormones, and the inability to push previous bests on the key intensity days, due to a fried peripheral system (tired legs). Typically, athletes who have gained the durability (through volume) to race a double ironman, don't have the speed potential to be competitive at the single iron distance. This is the same with ultra-marathon runners versus marathon runners. Due to this realization, more isn't always better. Instead, just enough (for required durability), with good quality mixed in at the appropriate doses, is the correct approach. Gain adequate durability for your race distance and then work on increasing speed potential. Build volume slowly over many years (add 10-15% max per year), mix in VERY good quality workouts, and never do anything today that even has the slightest chance of risking tomorrow...


Jesse Kropelnicki is an elite/pro level triathlon coach who founded QT2 Systems, LLC; a leading provider of personal triathlon and run coaching/nutrition. Besides his primary focus of coaching, Jesse is a veteran age group triathlete, and member of the QT2 Elite Triathlon Team. He is the triathlon coach of Caitlin Snow and Tim Snow among others; Nutrition advisor for professional triathletes Dede Griesbauer, and Ethan Brown; as well as nutrition/cardio advisor for professional UFC fighter Kenny Florian. His interests lie in coaching professional triathletes using quantitative training and nutrition protocols. You can track his other coaching comments/ideas via his blog at www.kropelnicki.com.