80/20 Triathlon

Periodisation in an 80/20 Triathlon or Running World

Arguably Matt Fitzgerald’s most famous books about training derive their methodology from Dr Stephen Seiler’s research. 80/20 Running and 80/20 Triathlon are immensely popular books. This is a summary of the periodisation concepts from them.

This is part two of the seventh article about Periodisation (English spelling with an ‘s’, American spelling is traditionally with a ‘z’) and the methodologies from coaches that guided my early philosophies around periodisation of training seasons and event build ups. Have a read of last weeks article about Matt Fitzgerald and what he recommends from The Runner’s Edge:

The crux of the 80/20 methodology is “Do 80 percent of your training at low intensity and 20 percent at moderate and high intensities.” As Matt Fitzgerald goes on to further explain this rule is a rule of thumb and not to be followed religiously or precisely. He emphasises that there is an exception to this when in specific periods of training and there is a reason to deviate to emphasise a certain component of fitness.

There are plenty of internet experts that only have a cursory knowledge of the 80/20 methodology and are nearly evangelical that you won’t get fitness results if you don’t precisely measure your proportion of time at respective intensities. At the end of the day getting out the door and doing the training will generate results.

If you don’t precisely hit the 80/20 balance, it won’t matter much. As long as you are close, such as 78/22 or 82/18 your race results won’t be impacted significantly. However it’s best to avoid extremes such as 50/50 or 30/70 or 100/0. As Matt says “Don’t tie yourself in knots trying to aim for perfectly round numbers“.

Optimal results are achieved in a small range, rather than a precise figure. How wide that range is will very from one athlete to the next. Some athletes might find the range is as tight at 77-83% / 17-23% (low to mod-high intensity), and for others it might 70-90% / 10-30%. No one knows precisely, science hasn’t answered that particular question yet. As much as I want an answer for that, lets get a cure for COVID or cancer or something 😃

Matt Fitzgerald describes the periodisation of a programme starting with the base training. The main objective here is to increase volume that is appropriate for the athlete. He also recommends a higher percentage of training at the lower intensity. This will make the overall load lower and decrease the risk of injury during this phase. However he still advises to include a small amount of higher intensity training to prepare the body for the harder workouts that will follow.

The next phase is the Peak Phase when the 80/20 rule is in full effect.

The final phase is the Taper that leads into an important race or event. This is one or two weeks in duration where the primary goal is to rest, recover and get prepared to race. Training volume is decreased sharply whilst maintaining high-intensity workouts. Therefore low-intensity training maybe less than 80% during this phase, in a well planned and executed taper.

In 80/20 Triathlon Matt Fitzgerald describes a training cycle and a racing cycle. A training cycle is a block of training leading into a period of frequent races which is the racing cycle. This would be more common for athletes completing a series of shorter races of a number of weeks or a couple of months. During this phase you are not trying to add extra fitness but take advantage of the fitness already gained. The key to a successful Racing Cycle being that training between events is very-light, to limit the risk of injury or burnout.

With the 80/20 intensities, 80% is at low intensity and the remaining 20% is a combination of moderate- & high-intensity. But what is the correct balance for the 20%?? Dr Stephen Seiler’s research found that elite athletes typically do more high-intensity training than moderate-intensity training. Other research has indicated that 80% low-intensity, 0% moderate-intensity and 20% high-intensity is the way to go. Further research that has shown spectacular results to enhance running performance from 80% low-intensity, 10% moderate-intensity and 10% high-intensity. This evidence supports that moderate-intensity is more important when preparing for longer events. This makes sense when we look at the likely race intensity for a longer event, it’ll be more at the moderate end of the spectrum than the high-intensity.

Matt Fitzgerald recommends balancing the proportion between moderate-intensity and high-intensity depending on the event. If you are training for a shorter, faster race put more emphasis towards the high-intensity end of the spectrum and if you are training for a longer event put more of the remaining 20% towards moderate-intensity.


80/20 concepts aren’t new, in fact they have been around for a long time. Dr Stephen Seiler’s research didn’t invent the concept, his research identified that elite athletes across a range of sports training conformed to the ratio. Results come from following the principle and it doesn’t need to be followed precisely.

A breakthrough program for triathletes — beginner, intermediate, and advanced — showing how to balance training intensity to maximize performance — from a fitness expert and elite coach.

Cutting-edge research has proven that triathletes and other endurance athletes experience their greatest performance when they do 80 percent of their training at low intensity and the remaining 20 percent at moderate to high intensity. But the vast majority of recreational triathletes are caught in the so-called “moderate-intensity rut,” spending almost half of their time training too hard–harder than the pros. Training harder isn’t smarter; it actually results in low-grade chronic fatigue that prevents recreational athletes from getting the best results.

In 80/20 Triathlon, Matt Fitzgerald and David Warden lay out the real-world and scientific evidence, offering concrete tips and strategies, along with complete training plans for every distance–Sprint, Olympic, Half-Ironman, and Ironman–to help athletes implement the 80/20 rule of intensity balance. Benefits include reduced fatigue and injury risk, improved fitness, increased motivation, and better race results.


This revolutionary training method has been embraced by elite runners—with extraordinary results—and now you can do it, too.

Respected running and fitness expert Matt Fitzgerald explains how the 80/20 running program—in which you do 80 percent of runs at a lower intensity and just 20 percent at a higher intensity—is the best change runners of all abilities can make to improve their performance. With a thorough examination of the science and research behind this training method, 80/20 Running is a hands-on guide for runners of all levels with training programs for 5K, 10K, half-marathon, and marathon distances.

In 80/20 Running, you’ll discover how to transform your workouts to avoid burnout.

• Runs will become more pleasant and less draining
• You’ll carry less fatigue from one run to the next
• Your performance will improve in the few high-intensity runs
• Your fitness levels will reach new heights

80/20 Running promotes a message that all runners—as well as cyclists, triathletes, and even weight-loss seekers—can embrace: Get better results by making the majority of your workouts easier.

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