Bent Rønnestad – 80/20 Endurance

Bent Rønnestad

Many moons ago, I wrote a post for this blog that bore the title, “The Human Body Is Not a Smartphone.” In it I argued that endurance training methods cannot advance indefinitely in the way that technologies such as smartphones can. “Once the best ways to train and fuel the human body for distance racing have been discovered,” I wrote, “it is impossible to improve upon them further until and unless the human body changes enough for different methods to become optimal.”

Even as I composed these lines, I knew they weren’t completely true. The idea that, given enough time, the optimization of endurance training methods is more or less inevitable is based on the notion that endurance sport operates as a self-organizing system. “A what?” you say. A self-organizing system.

Data scientist David Green of Monash University defines self-organization as “the emergence of pattern and order in a system by internal processes, rather than external constraints or forces.” Natural evolution is the best example of a self-organizing system, but computer scientists and engineers are able to create artificial self-organizing systems that are capable of evolving optimal solutions to real-world problems such as managing runway traffic at airports. If you place a graph representing such an evolutionary process next to a graph representing improvement in, say, the men’s marathon world record from 1896 to today, the two curves will appear uncannily similar in shape—a compelling illustration of endurance sport’s self-organizing behavior.

There are important differences between human endurance sport and computer models of airport throughput, however. Most notably, endurance sport is a social system nested inside the larger societal system, and as such it is subject to certain braking forces on its evolution that manmade self-organizing systems are not. Tradition is one such factor. In my experience, the top endurance coaches don’t put as much effort into innovating as they might, and I think that’s simply because, as human beings, top endurance coaches are deferential to “the way things are done” in the sport, no different than how teachers are deferential to the traditions of the institution where they teach. Consequently, opportunities to do things a little better sometimes wait a little longer to be discovered than they do in tech.

Which brings us to the topic of this article. The innovation known as block periodization originated in the weightlifting realm, where the practice is widespread. In the endurance realm, the term carries a slightly different meaning and the practice is not as widespread. As it applies to endurance sports, block periodization entails separating the volume and intensity elements of training. For example, a runner might do a block of three high-intensity workouts one week and a block of six longer low-intensity workouts the next week.

The developers of block periodization saw it as a way to make training harder without making it more stressful. They presumed that elite athletes were already training as hard as they could in the traditional way, where high-volume, low-intensity interval training and high-intensity interval training are mixed. It seemed plausible that by separating these two different types of training, athletes could do more of both without necessarily doing either in excess. During high-intensity training weeks, athletes would not be limited by fatigue induced by long workouts at low intensity, and during volume weeks, athletes would not be limited by fatigue induced by high-intensity intervals workouts.

Among the leading scientific investigators of block periodization in endurance athletes is Bent Rønnestad of Inland Norway University. In a 2019 meta-analysis of his and others’ work in this area, Rønnestad and colleagues concluded, “Block periodization is an adequate, alternative training strategy to traditional periodization as evidenced by superior training effects on VO2max and [maximal power output] in athletes. The reviewed studies show promising effects for BP of endurance training; however, these results must be considered with some caution due to small studies with generally low methodological quality.”

The most recent study of the effects of block periodization was conducted by Polish researchers and published in the International Journal of Environmental Research and Public Health last month. Twenty competitive mountain bikers were separated into two groups. For eight weeks, members of one group followed a traditional periodization model where each week included a mix of low-intensity riding, high-intensity interval work, and sprint interval training, while the second group followed a block periodization model where 17-day blocks of low-intensity riding were alternated with 11-day blocks of HIIT and sprint interval sessions.

Both groups underwent physiological and performance testing before and after the eight-week training period. Improvements were about equal in the two groups in all measures except VO2max, where the traditional periodization group experienced bigger gains, going from 3.66 to 4.2 L∙min−1 compared to 3.75 to 4.0 L∙min−1 in the block periodization group.

Where does this leave us? For better or worse, training innovations that are disruptive to existing best practices need to have a better story to tell than “possibly slightly superior in some metrics according to some but not all studies” if they are to overcome the inertia of tradition. I stand ready to be an early adopter of the next such innovation that comes along, but block periodization probably ain’t it.

Recently one of my custom training plan clients emailed me with a question. He was three weeks out from the marathon he’d hired me to prepare him for and was somewhat alarmed to see that I had scheduled a 20-mile run featuring 16 miles at his goal marathon pace at the end of the current week. His question was, in essence: Is two weeks enough time to recover from such a big workout?

In reply, I told my client that if he couldn’t recover from such a big workout in less than two weeks, he had greater problems than a coach who doesn’t know how to plan a proper pre-race taper! A cheeky answer, I know, but I receive versions of this same question so often that my patience is wearing thin. That’s why I’m writing this article, in which I hope to dispel the widely held notion that it’s necessary to cut way back on training for a long time before an important race.

As chance would have it, the email exchange I just described happened around the same time a relevant new study appeared in the Scandinavian Journal of Medicine in Sports. Authored by Bent Rønnestad of Inland Norway University and Olav Vikmoen of the Norwegian Defense Research Establishment, the study looked at the effects of two different tapering protocols on “physiological and psychological variables of endurance performance” in elite cyclists. 

Nine athletes completed a traditional 11-day taper that maintained the normal frequency of high-intensity interval training and reduced overall training volume, while eight others did six days of stepped-up “overload training” followed by a compressed five-day taper. Testing was conducted at three points: immediately before the 11-day interventions, again on Day 7, and once more on Day 11. Cyclists in the compressed taper group exhibited significantly greater improvements in peak oxygen consumption (4 percent vs. 0.8 percent) and one-minute peak power output (5 percent vs. 0.9) and a slightly greater improvement in power output at lactate threshold intensity. In short, the compressed taper worked better than the traditional one.

This study was actually a follow-up to a small pilot study done two years before by a research team that included the same duo plus two other scientists. And when I say “small” I mean small: It was an individual case study involving an elite male cross-country mountain biker. During a two-week interval between World Cup races, this athlete underwent seven days of overload training followed by a five-day taper. Both objective and subjective measurements were taken throughout. As expected, the cyclist felt like crap and exhibited compromised physiology on Day 1 of tapering, but by Day 4 he reported feeling good and his numbers were well above baseline. And two days after that he felt like Superman.

This compressed tapering protocol was developed specifically for use by endurance athletes like mountain bike racers on the World Cup circuit with tight competition schedules. It’s simply impractical for these athletes to follow a traditional protocol, and these two studies show they can have their cake and eat it too—that is, work hard enough to stay fit and recover sufficiently to race on peak form—by stacking short periods of overload training with compressed tapers. But what the same experiments also indicate, more broadly, is that it just doesn’t take very long to recover from peak training loads.

Real-world evidence supports these findings. While most elite endurance athletes practice some version of the traditional tapering protocol, others have found success with a compressed taper. Triathlon legend Dave Scott, for example, didn’t lighten up his training until three days before the Ironman World Championship, and that didn’t stop him from winning it six times in the 1980s!

When I try to make the case for short tapers with individual athletes like the custom training plan client who emailed me about his big marathon-pace run, I often ask them the following question: “How do you typically feel and perform when you’re in a period of heavy training and you do a challenging workout that is preceded by two very light days?” The answer is always the same: They tend to feel good and perform well. So, then, I point out (springing the trap), if two easy days during a period of heavy training usually suffice to make you feel and perform well in a hard workout, how much more time do you really need to taper down for a race?

To be clear, I’m not trying to argue for a two-day taper before an event such as a marathon or an Ironman triathlon. My point, simply, is that the optimal pre-race taper is not as long as many athletes seem to think. So, if you ever hire me to create a custom training plan for you and the last big workouts seem dangerously close to race day, keep those worries to yourself and do as I tell you. You won’t regret it!

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