Wednesday, February 12, 2014

Marathon Training Specificity: At What Cost?

Marathon training... it can quickly become a complex beast. Chose your running website of choice or do a quick search for training plans and you'll end up with all sorts of ideas and theories (including this one). I would venture to say that the common theme between the marathon training plans you'll find is higher volumes and relatively lower intensities when compared to a 5K or 10K program.

But have you ever stopped to ask, "Why?" Why should an athlete need 20+ mile long runs and 80+ mile weeks? Why should an athlete complete 10 mile tempo runs instead of repeat 400s?

Well, I like to ask questions...

A couple of weeks ago, after helping give a class presentation on the dominance of East-African runners, one of my classmates made the comment that we, as "sports-scientists", tend to over-analyze things. She argued that instead of trying to figure out what makes some athletes better than others, we should just go back to the basics and focus on what we can do. I really struggled (and am still struggling) with my classmate's comment - it didn't so much address the topic of sports performance as much as it raised a philosophical dilemma: why do we question things?

Whether you realize it or not; it is making observations, formulating hypotheses and testing those hypotheses that drives innovation and enables change and progress. I would argue that this scientific method of sorts has led sports performances to where they are today. Certainly, we could stand idly by and keep doing whatever we've been doing, but where is the opportunity for progress there? In my eyes, it is not acceptable to fail to make observations and hypotheses because of your own laziness. We question because we seek answers. If you're not asking questions, you're at a stalemate.

Now, back the topic of marathon training... Certainly, there will be some degree of specialization or training focus. But too often, people put the marathon on a pedestal; viewing it as a special event, unlike any other, believing it takes special and specific preparation. Coaches and athletes often make the remarks "marathoners should put more emphasis on mileage and less on 'speed' or intensity to [somehow] develop their aerobic engine (what the hell is an 'aerobic engine' anyway?)." So these athletes often neglect training at high-intensities in favor of more low-intensity "aerobic" volume; completing 22-26 mile long runs, tempo-runs and marathon pace running in place of high intensity intervals or fartlek.

If this sounds familiar, I think it's time to reassess and ask, "what adaptation(s) will an athlete get from the different approaches, high-intensity vs. high-volume?" And "do high intensity intervals have a place in marathon training?"

To demonstrate, let's take two radically different workouts using a race specific approach - one for the marathon runner and one for the 5000m runner. Both of these workouts might be utilized late in a training cycle for the respective athlete. The marathoner's workout is 25km at marathon race pace (3:28/km), whereas the 5000m runner's workout is 5 x 1000km (60' r) just faster than current 5000m race pace (2:50-2:55/km). To speculate what adaptations the athletes may get from the workouts, we can look to past research, but we can also think about the physiological demands of the different workouts.

Demands:
25km @ marathon race pace - steady state VO2 @ ~70-80% VO2max, no lactate/H+ accumulation, recruitment of slower twitching/fatigue resistant fibers, glycogen depletion possible (87-88:00 of work)

5 x 1km(60s) @ 5000m race pace - 90-100% VO2max, greater reliance on anaerobic energy sources: high lactate/H+ accumulation, recruitment of faster twitching fibers, glycogen depletion possible (Jenkins et al., 1993; Abernethy et al., 1990; Gollnick et al., 1974)

In the end we have ~90:00 of steady state running or 20:00 of intermittent high-intensity intervals. So the question to ask is: which workout results in the greatest fitness gains, independent of "race specificity?"

We have a lot of research on the efficacy of high intensity intervals now. And the data is compelling (Jeul et al., 2010; Ronnestad at al., 2014; Laursen, 2010; Kubukeli, Noakes, & Dennis, 2002; Lindsay et al., 1996; Abernethy et al., 1990; Londeree, 1997; Sharp et al., 1986; Billat et al., 2002).

I can't summarize all of the findings of the research and reviews here. The studies cited above do not even begin to scratch the surface of the literature on high intensity and sprint intervals, but if you could read just two, I strongly urge you to look through the articles from Laursen (2010) and Billat (2002). A full text version of the article from Laursen can be found here.

Laursen points to the value of both, low-intensity-high-volume and high-intensity-low-volume training, noting that adaptations can come from either; through distinctly different pathways. Mitochondrial biogenesis may be promoted with high-intensity or sprint intervals by activation of the AMPK signalling pathway, while low-intensity-high-volume promotes biogenesis through activation of the calcium-calmodulin pathway. Certainly, the proliferation of mitochondria is not the only event that occurs with training, but it has been recognized as an important adaptation for endurance athletes (Costill, Fink, & Pollock, 1976). Other components of fitness are lactate threshold and running economy - both of which have been improved with high intensity and/or sprint intervals (Kubukeli et al., 2002; Gunnarsson et al, 2012; Barnes et al., 2013, Midgley et al.,2007; Denadai et al., 2006)

Billat (2002) found that an 8 week "pre-competetive phase" of training, including high-intensity interval training at velocities faster than 10,000m race pace, improved VO2peak and subsequently decreased O2 fractional utilization at marathon pace. This means that the runners could maintain the same pace and run at a lower percentage of their VO2max potentially decreasing reliance on glycolysis (and glucose) for ATP production. Interestingly, high-intensity interval training also decreased the runners' time over an all-out 1000m. Could 1000m time and marathon performance be correlated? But that could mean that maximal sustainable velocity/pH threshold and marathon performance are correlated... Oh, my! We've really opened a can of worms now! What implications could this have for 3:28 1500m man, Mo Farah?

These findings prompt the question, why not go after adaptation by employing both strategies (high and low intensity training)? This is nothing profound, coaches and athletes have been utilizing "polarized" approaches to training, like the one described in the article from Billat (2002), for decades. The key point being, marathon runners should not neglect high-intensity or sprint intervals.

Below is an example of a polarized approach to marathon training that utilizes high and low-intensity training. Obviously, low-intensity "easy" runs would be performed on non-workout days. And of course, any of these interval workouts could be replaced with a fartlek of similar time and effort.

Full screen training plan in a new tab: here


Just like that, we have a polarized marathon training plan that encompasses high-intensity intervals and low-intensity "endurance" runs. Just as Juel et al (2010) found, by focusing on high-intensity intervals early in the training block, the athlete develops the ability to buffer H+ ions, improve blood flow and extend time to exhaustion - potentially improving an athletes ability to work at higher workrates/velocities. This may enable the athlete to complete the longer intervals in the subsequent block of training at faster paces, increasing the training stimulus which could lead to greater race performances. All the athlete is working towards is increasing his maximal sustainable pace and this is done by increasing "fitness" (lactate threshold, VO2max and running economy). I will admit, my current training philosophy is strongly influenced by my interactions with physiologist and coach, David Morris. His book can be found here.

So, instead of viewing the marathon as a "special" race that requires specific preparation, view it as an opportunity to increase the athlete's fitness that in turn, enables him/her to sustain a faster pace, no matter what the distance. Given the past research, as well as anecdotal evidence (here and here), I think it's pretty clear that fitness gains will come from high-intensity intervals and those fitness gains enable athletes to maintain greater velocities over any race distance. High intensity intervals may not be "specific" to marathon pace or race demands, but that seems to be a good thing.

References
Abernethy, P. J., Thayer, R., & Taylor, A. W. (1990). Acute and chronic responses of skeletal muscle to endurance and sprint exercise. A review. Sports Med, 10(6), 365-389.
Barnes, K. R., Hopkins, W. G., McGuigan, M. R., & Kilding, A. E. (2013). Effects of Different Uphill Interval-Training Programs on Running Economy and Performance. Int J Sports Physiol Perform.
Billat, V., Demarle, A., Paiva, M., & Koralsztein, J. P. (2002). Effect of training on the physiological factors of performance in elite marathon runners (males and females). Int J Sports Med, 23(5), 336-341. doi: 10.1055/s-2002-33265
Costill, D. L., Fink, W. J., & Pollock, M. L. (1976). Muscle fiber composition and enzyme activities of elite distance runners. Med Sci Sports, 8(2), 96-100.
Denadai, B. S., Ortiz, M. J., Greco, C. C., & de Mello, M. T. (2006). Interval training at 95% and 100% of the velocity at VO2 max: effects on aerobic physiological indexes and running performance. Appl Physiol Nutr Metab, 31(6), 737-743.
Gunnarsson, T. P., Christensen, P. M., Holse, K., Christiansen, D., & Bangsbo, J. (2012). Effect of additional speed endurance training on performance and muscle adaptations. Med Sci Sports Exerc, 44(10), 1942-1948.
Jenkins, D. G., Palmer, J., & Spillman, D. (1993). The influence of dietary carbohydrate on performance of supramaximal intermittent exercise. Eur J Appl Physiol Occup Physiol, 67(4), 309-314.
Juel, C., Klarskov, C., Nielsen, J. J., Krustrup, P., Mohr, M., & Bangsbo, J. (2004). Effect of high-intensity intermittent training on lactate and H+ release from human skeletal muscle. Am J Physiol Endocrinol Metab, 286(2), E245-251.
Kubukeli, Z. N., Noakes, T. D., & Dennis, S. C. (2002). Training techniques to improve endurance exercise performances. Sports Med, 32(8), 489-509.
Laursen, P. B. (2010). Training for intense exercise performance: high-intensity or high-volume training? Scand J Med Sci Sports, 20 Suppl 2, 1-10.
Lindsay, F. H., Hawley, J. A., Myburgh, K. H., Schomer, H. H., Noakes, T. D., & Dennis, S. C. (1996). Improved athletic performance in highly trained cyclists after interval training. Med Sci Sports Exerc, 28(11), 1427-1434.
Londeree, B. R. (1997). Effect of training on lactate/ventilatory thresholds: a meta-analysis. Med Sci Sports Exerc, 29(6), 837-843.
Midgley, A. W., McNaughton, L. R., & Jones, A. M. (2007). Training to enhance the physiological determinants of long-distance running performance: can valid recommendations be given to runners and coaches based on current scientific knowledge? Sports Med, 37(10), 857-880.
Ronnestad, B. R., Hansen, J., Vegge, G., Tonnessen, E., & Slettalokken, G. (2014). Short intervals induce superior training adaptations compared with long intervals in cyclists - An effort-matched approach. Scand J Med Sci Sports.

Sharp, R. L., Costill, D. L., Fink, W. J., & King, D. S. (1986). Effects of eight weeks of bicycle ergometer sprint training on human muscle buffer capacity. Int J Sports Med, 7(1), 13-17.

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