The other day I attended a talk by Jonathan based on his own research and the results of the athletes he coached through the Klagenfurt Ironman (Austria) this year. What was surprising, given the small sample (7) of those who could actually be bothered to fill in all the information on how many minutes they spent training in each sport and at each intensity, was how faithfully the results confirmed his hypotheses.
I've talked before about the concept of "polarized training", which means that you perform the majority of your training (approximately 80%) at below your aerobic threshold and the rest (20%) at above your anaerobic threshold. This was basically the premise of his talk but it was very interesting to understand where this idea comes from.
One of the papers he cited, by Fikerstrand and Seiler, was a study of Norwegian Rowers from 1970 up until 2001. The paper showed that one of the main changes in training which could account for the increase in performance in these rowers was a polarization of their training intensities. It is interesting to bear in mind that the event they were training for lasts approximately 6 minutes, a world apart from an Ironman event which can take anything from 8 hours to 17 hours (the cut off which, incidentally, is the time that the creator of the event took to complete it in 1978).
Another interesting nugget is that, if you look at the training patterns of elite Marathon runners, they spend only 4% of their total training time running at Marathon pace (and even this is probably in tune up half Marathon races)! This reminds me a little of the rowing training I did in the 90s, where we would either do underdistance (sprints) or overdistance (steady state) but, of course, no-one trains overdistance for the Marathon. What is hard to accept, as I have said many times before, is that you are doing some good by training underdistance and below pace.
Jonathan did various regressions of the performance (time) of each of the athletes who competed in the Klagenfurt Ironman (by the way, everyone he coached completed the event) against different parameters. There was clearly a correlation between overall training time and performance but, what was significant, was that there was no notable correlation between performance and "TRIMPS" - an objective measure of training intensity and volume. In particular, there was a high correlation between time spent training in zone I (below aerobic threshold) and performance, a very low correlation between time spent in zone III (above anaerobic threshold) and performance and a significant anti-correlation between time spent in zone II (between the two) and performance.
Why should this be? Surely, there should be more performance benefit from training in zone III? And how is it possible that training in zone II is bad? The argument goes something like this. Let's suppose that we have a limited amount of time in which we can train (this is always the case in practice but, for non-professional athletes it is a much more obvious limitant). How should you divide up those X hours a week between the different zones? The so called "high quality" training (a euphemism for "high pain" if ever I heard one) is very beneficial to speed but it is also very stressful for the body. The body needs time to adapt to the stresses placed upon it (recovery or "supercompensation") before it can be re-stressed; otherwise injury results. Not only can you be doing low intensity, zone I, work in the meantime, it appears that the zone I work helps the body adapt to the stresses of zone III training, as well as developing the aerobic fat burning engine.
I have to admit I work in a bank so I'll give you an analogy from an investment point of view. If you had a fixed amount of money to invest, you might choose to invest a proportion of it in high risk investments and the rest in low risk investments. It would be foolish to put all your money at risk - although you might be lucky of course - and, it would be suboptimal to put all your money in a low yielding, conservative fund. The same idea applies here - you should invest only a proportion of your training time in the high risk zone III and the rest in the safe but boring zone I. The reason that there is no sense in investing time in zone II is that it doesn't appear to promote specific adaptations in the body as effectively as the other zones and it has the added disadvantage of tiring you out more for your next zone III workout. (In the finance analogy, imagine that you get a free Playstation by placing money in the low risk fund...)
I suppose that the optimal proportion of time in zone I to zone III could vary from one individual to another (just as risk preferences do) but, for now, we will accept that one should spend 4 hours in zone I for every hour in zone III. In practice, we tend to do our series at a little bit less that zone I if we are tired - another reason to not overdo the amount of zone I training - and it is sometimes difficult to do all zone III training in the zone because there are hills, gusts of wind, or we just get bored and want to get home sooner. Furthermore, some proportion of races of distance more than 5k will be run in zone II, so it is inevitable that a percentage of training time will end up in this category. In the case of our Klagenfurt athletes, 75% of training time was spent in zone I, 21% in zone II and 4% in zone III; in the competition itself, the numbers were remarkably similar except that, of course, zone I and zone II were switched around.
(By the way, we haven't even mentioned the most obvious things to try to correlate: performance and physiology or talent - be it measured in VO2max or whatever. This is what struck me most looking at the graphs in the presentation, that performance seemed to be dictated by hours of work alone - this would mean hope for the less blessed but determined amongst us! Perhaps an explanation for this is that the number of hours one can tolerate in training is linked to one's physiology and, similarly, the more competitive the athlete, the more of a priority training will be for them.)
The conclusion was basically that, if you want to do an Ironman:
- you have to put in the hours (10-15 hours weekly as a minimum);
- you should save yourself for the hard training days and not be tempted to push it just because you feel good
- and you should stick to your training plan!
A last point that Jonathan brought up was the importance of strength training. When you run, forces of several times your body weight ripple through your muscles, tendons, ligaments and bones a thousand times per kilometer. Anecdotally, he has been able to spot those athletes who are about to get injured as those who struggle to squat (lift with legs in standing position) 1.4 times their body weight (+1 for the weight of their own body, of course).