Our co-author of the book The Power to Run (expected March 2022) Koen de Jong uses the Yasso 800s method for his marathon training and asked us if we knew the method and could calculate the required power to run the Yasso intervals. We answered in the affirmative to both questions and in this article we explain the method.

What is the Yasso 800s?

The Yasso 800s was created by Bart Yasso, the Chief Running Officer of the American magazine Runner’s World. Bart Yasso has been inducted into the Running USA Hall of Champions and is referred to in America as the ‘Mayor of Running’. He has raced on all 7 continents and has won the U.S. Duathlon Championship in 1987.

His method is very simple and consists of running a number of intervals over 800 meters. The trick is that you have to make sure that your time over the 800 meters (in minutes and seconds) is equal to your marathon goal time (in hours and minutes). So if you run (or want to run) a marathon in 3 hours you have to run the 800 meters in 3 minutes. How simple can it be?

The structure of the workout is also very simple:

• Warm-up for 10 minutes (gentle jogging, exercises and possibly some 100 meter strides to get used to the speed)
• 800 meter interval at the converted pace (so 3 minutes for a marathon time of 3 hours)
• Recovery during the same time as the interval (so 3 minutes in the example)
• Repetitions: in the beginning 3 or 4 times, expand to finally 10 times
• Cooling down for 5 or 10 minutes, including exercises/stretching.

And voilà, you’re done!

Bart Yasso recommends doing this workout 1 time a week. The method is very popular and also successful. It is recommended to do the other parts of a full marathon training during the rest of the week, especially the long endurance runs, the recovery runs and the pace training.

What power should you use for the Yasso 800s?

In the table below we have worked out some examples.
The first column shows the (desired) marathon time.
In the second column we have determined the corresponding marathon power with the formula: Watts/kg = speed in m/s*1.04. In a previous article we showed that this gives a very good approach for most runners.
The third column shows the time for the Yasso 800s in minutes and seconds, which as mentioned equals the marathon time in hours and minutes.
In the fourth column, the required power for the 800 meters is calculated (with the same formula).
In the fifth column we have finally calculated how much extra power you have to use during the 800 meters compared to your marathon power. This always turns out to be 13.76% with this method.

Critical analysis of the Yasso 800s

At first glance, this method seems too simple to be true. You would think: how is it possible to base a marathon time on intervals over 800 meters and vice versa?

Still, there’s something in it. Of course, you run slower as the distance increases. In our books we have shown that for most people the speed decreases by 5% when the distance doubles. Now of course there are people with a particularly good endurance, but when you cannot run an 800 meter interval in 3 minutes you can forget about running a marathon in 3 hours. No matter how good your stamina is! That there is a more or less fixed relationship between the 800 meters and the marathon time is therefore not entirely surprising, although this will not be exactly the same for everyone.

At its core, the Yasso 800s is ‘just’ an interval workout where the pace of the intervals is not determined by your trainer, but by your desired marathon time. In another previous article, we explained that interval training is an important building block to become a better runner. With the Yasso 800s, the pace of your intervals is therefore adjusted to your level, in this case by the marathon goal time you can or want to run. If you don’t reach that level, you’ll have to adjust the pace of your workouts and the expectations for the marathon….

Intervals make you a better runner

Many performance-oriented runners train at least once a week at their club on the athletics track. Traditionally, your trainer often bases the schedules for interval training on your 10K race time. On another day in the week, some longer intervals, accelerations or hills in the workout on the road or in the forest are on the program.

The reason is that with intervals you can train at high intensity. It improves your base speed. The goal can also be to train your various energy systems (you have four!) or to get your body used to lactate acid. Because recovery is built in between intervals, these types of training are less stressful as a race.

800 meter intervals at 109%?

In our earlier article, we gave the table below for the required power as a function of the distance of the intervals. For intervals of 800 meters, we indicated that you have to run it at 109% of your FTP (the power that you can maintain for 1 hour).

The fact that you see the percentages increase quite a bit at short interval distances is caused by the fact that your anaerobic energy systems provide extra energy there. Your anaerobic fuel supply is very limited. You can therefore only keep these high powers and speeds up for a short time.

What about the Yasso 800s? Do you also run it on 109% of your FTP? We have calculated that for the examples, see the table below. The first 2 columns are the same as in the first table, but in the third column we have calculated the FTP that is equivalent to the marathon time. In the fourth column we have finally calculated the required power for the 800s as a percentage of your FTP. Because your marathon power is relatively lower compared to your FTP at slower marathon times, you see that the percentage with which you have to run the 800 meters slowly decreases.

The result of these calculations is that the top runners with the Yasso method have to train almost at 109% of their FTP, but that for slower runners the percentage drops to order 103%. The training is therefore less stressful for them, especially since the recovery time at Yasso is rather long (after all, as long as the interval itself, so 4 minutes if you run a marathon in 4 minutes).

Our conclusion is that the Yasso 800s is a great method to determine the pace for your intervals on your individual level, based on your marathon time. For slower runners, the pace seems to be a bit too slow and the recovery time is also a bit too long. However, it does seem a bit dubious to us to calculate your marathon time based on your Yasso 800s interval times. Keep in mind that in the marathon you may ‘hit the wall’ and your stamina may be better or less than average.

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Our book ‘The Secret of Running’ is for sale in our webshop. Also available in German as ‘Das Geheimnis des Laufens’, and in Italian as ‘Manuale completo della corsa’

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Koen de Jong ran a PB at the marathon of Den Bosch (the Netherlands) with the help of a Stryd running power meter. Shortly before that, we had explained the benefits of running on power in a joint webinar. That has inspired many Dutch runners to buy a Stryd.

Attaching such a Stryd to the shoelaces is a breeze. But then what?

The simplest answer is a reference to the website Stryd.com. There’s an incredible amount of information there. Another easy answer refers to our new book ‘Your easiest way to a PB: Running on Power’. As an e-book, this new book can be freely downloaded. The paperback version is for sale at cost price, also in the regular bookstore. The e-book as well as the paperback are in Dutch. Other languages will follow.

Free? ProRun offers the book as a service to its readers and all other running enthusiasts.

Hans van Dijk, Ron van Megen and Koen de Jong wrote this book because they believe in this revolutionary running development. The Stryd running power meter is part of an entire ecosystem of possibilities and insights to improve your running.

Nevertheless, the most frequently asked question via the websites of ProRun.nl and TheSecretofRunning.com was “Can I find out how to get started quickly?”. We address that question in this article.

Out of the box

The Stryd footpod comes together in a nice box with a USB charging cable and two clips to attach the footpod to the laces of your shoe. The footpod needs to be charged first. You repeat that every 2-3 weeks, depending on how much you run. In your mobile phone’s Stryd app, you can see how full your Stryd’s battery is (in “settings”).

Next, see if your Stryd has the latest firmware. For this you also go to “settings” in the Stryd app and then to “Stryd”. The current firmware version is 2.1.16. Stryd has announced a next firmware version. From then on, the Stryd measures the data hundreds of times per second and becomes even more accurate than it already is. Stryd is continuously working on the firmware so that it stays up to date , can work with the latest models of watches and offers new features.

With “settings” and “Stryd” you immediately enter your height and weight. This data needs the Stryd when calculating the air resistance (the c_dA value, your personal resistance surface in m²) and of course for the calculation of the wattage with which you are running. The Stryd determines this in watts per kg (e.g. 3.1 watts/kg). By multiplying it with your body weight (e.g. 70 kg), you get to see the value 217 watts on the screen of your running watch (3.1*70 = 217).

Where did you get that Stryd app? It goes the usual way for your mobile phone. With iPhone, that’s the App store. You search for Stryd there and install the app.

Then you link the app to your Stryd. In settings you will see the serial number of your Stryd. This number can be useful if you want to pair your sports watch and at that moment also the Stryd of your partner or a running buddy is nearby. For example, you can connect the Stryd to a Garmin by going to “sensors and accessories” on your Garmin and having it search for the Stryd with “Add new”.

With the Stryd app you can also create your account with Stryd. All data will then end up in the

Stryd cloud environment and all uses will be at your disposal.

We recommend that you also use PowerCenter with the same login details. You can find this on the internet at Stryd.com. The information in PowerCenter is based on the same data already in the Stryd app. Both are linked to the Stryd cloud environment. We find PowerCenter useful because you see everything a little bigger on the screen of your PC. Because of the overview dragging a training from the schedule to a day that you can train, for example, is easier for us on a screen with a mouse. That’s probably up to us too, more than 70% of all Stryd users use the app on the phone.

You can attach the Stryd to the laces by sliding the clip at the nose of your shoe under the XI or XXI of your laces and clicking the footpod into the clip. Stryd explains this in a video.

It is important that the footpod is firmly fixed, does not move, with the small tip stuck forward, and the hole of the windport (for the measurement of wind resistance) remains free.

We sometimes get comments that the measured wind resistance is very low. That may have to do with the oblique lacing of the shoe, as is the case with the Nike Vaporfly 4% and Nike Next%. Stryd also has a video with a solution for this. In an occasional case, there is another cause associated with the design and material of the shoe. According to Stryd, the new firmware contains a solution for these rare situations.

Finally, pair your new Stryd with your running watch. There are many (and more and more) brands and models that are suitable for this. You can look this up on the Stryd website.

Coros watches have Stryd fully integrated. Garmin is a good second with IQ apps specific to Stryd. Polar and other watches can also handle it without any problems.

Ron makes use of Garmin Connect. Garmin Connect has paired it with the Stryd app and PowerCenter. All Stryd data will run automatically in Garmin Connect after saving to your watch and then in the Stryd cloud environment (Stryd app and PowerCenter).

With a number of watches there is a point of attention. Polar itself knows Polar Running Power. Wattage at running is therefore not a problem to pass on via Polar Flow to the Stryd cloud environment, but wind resistance, form power, leg spring stiffness do not come along. Polar Running Power does not know these concepts. This can be solved by going back to “settings”in the Stryd app on your phone, then to “Stryd” and then choosing “Sync Stryd”. Then all data directly from the Stryd footpod enters the Stryd cloud environment. You don’t have to worry about data being duplicated. It’s guarded for you.

The first beginning

The Stryd footpod should get to know you at first. That’s fast, but it’s not accurate in the first few days. As you have run more short and long distances at race pace, this is becoming more and more accurate.

Two concepts are of primary importance:

– critical power (CP)

– power duration curve

Briefly summarized, the critical power (CP) is the power with which you can run a 10K. If you keep that wattage, you’ll run the fastest time for a 10K.

Hans and Ron use in their book ‘The Secret of Running’ and articles the term Functional Threshold Power (FTP). This is the power you can sustain for an hour. That calculates more easily to the times for different distances. You can have your FTP determined during a test at a Sports Medical Advisory Centre. You can also just read from the power duration curve. This power curve shows which maximum wattages you have demonstrably run during the last 90 days (and therefore fairly current) during the duration indicated on the x-axis.

Stryd has a blog with some tips to quickly arrive at a first CP.

As time goes on, you’ll get notifications that your CP has been updated. This is because more and more data about you become available over time and the CP is therefore more accurately determined. Of course, it is also possible that your training will make you a better runner.

If you train less for a while, your performance will deteriorate. Your CP will drop. After 90 days, performance falls out of your power curve. And recent data count more heavily than older data. Stryd uses 1-30 days, 31-75 days and 76-90 days. If you want to know more about this, you can read it in a blog on Stryd.com.

Daily use

Of course, you don’t have to have trained with the Stryd for 90 days to make use of the possibilities. You can do that almost immediately. Here are two interesting options:

– the race calculator

– power-based training schedules

In the race calculator you can indicate which distance you are going to run. There will then be a prognosis of your time and advice on the power to maintain in the race. This is based on your critical power (CP) and your power duration curve. In the race calculator you also indicate at what temperature you have trained and what the temperature is on the race day. The same goes for the humidity and elevation above sea level.

You can even load a .fit-file or .gpx file with the details of the race course. Some race organizations make them available on the website. And if you’ve run the race before, you can use last time’s file. In the example below Ron put the Zevenheuvelenloop in the race calculator. That 1:20:04 would definitely not produce a PR, but Ron is also not in great shape due to the corona pandemic.

The graph of the Seven Hills Run (Nijmegen, The Nethelands) shows that Ron can now run it with 270 watts (and then reach 1:20:04). The blue line shows that at a constant power (270 watts) the uphill pace is slower and downhill faster for the fastest end time.

In addition to being able to enter races yourself in the race calculator, a few major marathons, such as Berlin (September 26, 2021), are already pre-programmed. Nice to see what you could run there with your current shape.

If you put the Berlin marathon (as an example) in the calendar of your Stryd, with every change of your CP you will see the predicted finish time and the recommended power change. Inspiring to see if you train especially for a race and that training starts to bear fruit.

For Berlin (or any other race) you can choose a training schedule. You indicate which distance you will run, when the race day is, how many days in the week you can train, on which day you usually have time for a long endurance run, and how many hours you can train in the week. You will then be presented with a training schedule.

In the calendar of the Stryd app and in PowerCenter, a personal training is then specified from day to day. If you can’t do a day, you can drag the workout to another day. You can also exchange training sessions with each other. The training intensity is linked to your CP. If your CP improves, the wattages you need to train with automatically change with it. You can sync the workout with your Garmin. With beeps and countdowns you can finish your training without having to remember much.

You can read all about running on power and the effect of all factors on your performance in our book The Secret of Running. 

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Our book ‘The Secret of Running’ is for sale in our webshop. Also available in German as ‘Das Geheimnis des Laufens’, and in Italian as ‘Manuale completo della corsa’

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How do you eat as healthily as possible? (Photo: Pixabay)

In the first article we showed that a high VO₂ max significantly reduces the risk of premature death from cardiovascular diseases and also from other diseases including even cancer. We therefore introduced the concept of fitness age and a calculator to calculate it.

In the second article we presented an additional analysis of life expectancy. After all, your life expectancy is also influenced by other factors, such as smoking, diet, blood pressure, cholesterol, heredity, lifestyle and psychological factors (feelings of happiness, stress). These factors can be expressed in the concept of biological age. You can then determine your broad life expectancy, which is equal to the standard life expectancy plus the difference between your age and your biological age.

We concluded this article with the following 10 rules for a healthy lifestyle. If you live according to these rules, the chance to reach a high age is maximized!

Lifestyle rules: the key to a long life

1. Do not smoke
2. Sleep soundly
3. Train regularly and intensively
4. Laugh to the fullest and enjoy your life
5. Enjoy your relationship and your friends
6. Manage your stress level
7. Eat plenty of fruits and vegetables
8. Avoid too much alcohol, sugar, salt, fat (saturated) and processed foods
9. Avoid high blood pressure
10. Avoid risks and environmental pollution

In the third article we looked at the efficiency of training and calculated how much your life expectancy increases per hour you train. The conclusion was that the return on investment from training is very favourable: your ‘profit’ in life expectancy is far more than the ‘investment’ in training hours.

In the fourth article we dealt with the influence of personality and lifestyle using the book of the Canadian and 60-time world record holder Earl Fee “100 Years Young, the natural way“. In our article we have summarized some telling examples:

1. Importance of optimism, positive thinking and feelings of happiness
2. Importance of good habits
3. Importance of ‘mental exercise
4. Importance of ‘cleaning up
5. Importance of spiritual thinking

How does nutrition affect your health and life expectancy?

Today we close the series with an article about the influence of nutrition. Is there a causal link between nutrition and disease or life expectancy? We have read a lot of literature on this subject, including the book of emeritus professor of nutrition Prof. Martijn Katan “Nutrition myths“. He concludes that we are swamped with reports of beneficial or harmful effects of food and drink. The so-called beneficial effects are often not based on hard science, nor are the supposed adverse effects. Katan argues that there are many myths about nutrition. These myths arise because researchers allow themselves to be tempted to thicken their findings. This leads to exaggerated press releases. The media are happy to publish them because food news is always popular. Nutritional myths meet many needs, including those of the food industry, which often funds research….

In his book Katan deals with seventy food myths. He ends with the message: News about nutrition can usually be ignored. The information in the media is usually new and exciting but almost always wrong and not based on hard science.

So what kind of hard science is there about the influence of food on our health and life expectancy?

In our opinion, the best source for this is the Health Council of the Netherlands’ advisory report “Guidelines for Good Nutrition 2015“. This is the official advice to the Dutch Cabinet and Parliament from an extensive committee in which virtually all Dutch experts in the field of nutrition were represented. It was not made in haste, because the Minister’s request for advice dates back to 1998….. In those intervening years the current state of the science was summarized. Among other things, this has resulted in 29 background documents on individual foodstuffs. The advice itself counts 93 pages and can be seen as a summary of the state of the science on the basis of strict quality requirements. In addition to the committee, the Dutch Nutrition Centre and the Dutch National Institute for Public Health and the Environment also contributed to the advice.

Research Methodology Guidelines Good Nutrition 2015

The committee has investigated the relationship between food and the risk of chronic diseases. It primarily looked at the Dutch top 10 diseases, namely coronary heart disease, stroke, heart failure, diabetes, chronic obstructive pulmonary disease (COPD), breast cancer, colon cancer, lung cancer, dementia and depression. In addition, the committee looked at risk factors, for which a causal relationship with at least one chronic disease has been demonstrated. These are systolic blood pressure, LDL cholesterol and body weight.

In terms of types of research, the committee distinguishes between randomized and controlled intervention research (RCTs) and prospective cohort research. 

In RCTs, participants are divided into groups on the basis of chance, with one group receiving treatment (food) and the other group serving as control. Well-executed research of this type provides the best clues to the causality of a relationship. From RCTs, the committee draws conclusions about the effects of intake on causal risk factors and chronic diseases in the various background documents and about the level of evidence for these conclusions.

In cohort research, the link between nutrition and chronic diseases is investigated without the researcher intervening in the existing situation. Cohort research provides less strong evidence for causality because bias can never be excluded. The question is whether sufficient corrections have been made for the influence of lifestyle variables (smoking, alcohol consumption, exercise, etc.).

Finally, the committee made use of publications from peer-reviewed journals in which data from several studies were published, the so-called meta-analyses. These give a greater statistical power of discernment and a more accurate estimation of a correlation.

The figure below from the advice gives an overview of the research methodology used.

In formulating guidelines, the committee has based itself on conclusions with great evidential value:

• The food affects a causal risk factor. These are results from
• The food is related to the risk of disease. These are results from a cohort study, we speak of a connection.

Summary Advice Guidelines Good Nutrition

The core of the advice is to eat according to a more plant-based and less animal-based diet. This is elaborated in guidelines for the food products fruit and vegetables, meat, fish, nuts, legumes, cereals, butter and oil, beverages, alcohol, cooking salt and food supplements. In the table below we have summarized the advice.

In this article we will point out the most important conclusions:

1. Fruit and Vegetables

The committee concludes that it has been convincingly demonstrated that eating fruit and vegetables reduces the risk of coronary heart disease and stroke. Cohort research also shows that eating fruit and vegetables is associated with a lower risk of diabetes, colon cancer and lung cancer. The recommended amount is 200 grams of vegetables and 200 grams of fruit. On average, Dutch people eat too little vegetables (125 grams) and fruit (120 grams).

2. Wholemeal bread and wholemeal products

The committee concludes that there is convincing evidence that the consumption of wholemeal products reduces the risk of coronary heart disease and stroke. Cohort research also shows that eating wholemeal products is associated with a lower risk of diabetes and colon cancer. The recommended amount is 90 grams per day; the average consumption in the Netherlands is approximately at this level.

3. Pulses

The committee concludes that it has been convincingly demonstrated that the consumption of legumes lowers LDL cholesterol and thus the risk of coronary heart disease. Incidentally, half of the population in the Netherlands eat little or no legumes (soybeans, lentils, chickpeas or split peas).

4. Unsalted nuts

The committee concludes that it has been convincingly demonstrated that consumption of unsalted nuts reduces the risk of coronary heart disease. The recommended amount is 15 grams per day, in the Netherlands half of the population does not eat unsalted nuts (walnuts, almonds, hazelnuts, cashew nuts, pistachios, macadam nuts, Brazil nuts and peanuts).

5. Dairy

The committee concludes that it is plausible that the consumption of dairy products is associated with a lower risk of intestinal cancer and diabetes. The recommended amount is a few servings per day, including milk or yogurt. The average dairy consumption in the Netherlands is at this level.

6. Oily fish

The committee concludes that it has been convincingly demonstrated that eating fish reduces the risk of coronary heart disease. In cohort research, eating fish is also associated with a lower risk of stroke. The recommended consumption is to eat fish once a week, preferably fatty fish (herring, salmon, mackerel). In the Netherlands, half of the population eats 2 to 3 servings of fish per month.

7. Tea

The committee concludes that there is convincing evidence that the consumption of tea reduces the risk of stroke. It is also plausible that the consumption of tea is associated with a lower risk of diabetes. The recommended quantity is 3 cups per day.

8. Replace refined cereal products with whole grain products

The committee stresses the importance of replacing refined with unrefined grain products. Replacing sugars with starch leads to a reduction of LDL cholesterol. Starch is a healthier source of carbohydrates than sugars. The average consumption of refined cereal products (white bread, pasta, etc.) in the Netherlands is about 100 grams per day.

9. Replace butter and roasting fats with liquid fats and vegetable oils

The committee concludes that it has been convincingly demonstrated that replacing butter and frying fats with liquid fats and platear oils reduces the risk of coronary heart disease.

10. Replace unfiltered coffee with filtered coffee

The committee concludes that it has been convincingly demonstrated that unfiltered coffee increases LDL cholesterol and thus the risk of coronary heart disease. In cohort research, the use of filtered coffee is associated with a lower risk of heart disease, stroke and diabetes.

11. Eat little red or processed meat

The committee concludes that it is plausible that there is a link between the consumption of red meat and processed meat and a higher risk of stroke, diabetes, intestinal cancer and lung cancer. The link is stronger with processed meat than with red meat.

The guideline is to limit the consumption of red meat and especially processed meat. On average, Dutch men eat about 105 grams of red meat per day and 55 grams of processed meat.

12. Beverages containing sugar

The committee concludes that it has been convincingly demonstrated that the consumption of sugary drinks increases the risk of diabetes. Good alternatives are water, tea and coffee.

13. Alcohol

The committee concludes that it has been convincingly demonstrated that high alcohol consumption increases the risk of stroke. In addition, high alcohol consumption is associated with a higher risk of breast cancer, bowel cancer and lung cancer. However, it is plausible that moderate alcohol consumption is associated with a lower risk of cardiovascular disease, diabetes and dementia. Low wine consumption is associated with a lower overall mortality rate. The committee recommends not drinking alcohol or at least not more than 1 glass a day.

14. Kitchen salt

The committee concludes that it has been convincingly demonstrated that a reduction in sodium intake lowers blood pressure and thus the risk of cardiovascular disease. The recommendation is to limit the intake to 6 grams of table salt per day. The average intake for Dutch men is currently 10 grams per day.

15. Food supplements

The committee concludes that the use of dietary supplements is not necessary, except for people belonging to a specific group for whom supplementation advice applies. Examples are vitamin D advice for young children, pregnant women, the elderly and people with dark skin or body covering clothing. Pregnant women need extra folic acid and vegans need extra vitamin B12.

In addition to the recommendations for specific foods, the committee also looked at so-called ‘recommended diets’, such as the Mediterranean diet, the Scandinavian diet and the American Dietary Approaches to Stop Hypertension (DASH). These patterns score high on the use of vegetables, fruits, wholemeal products, nuts, legumes, vegetable oils, skimmed dairy, poultry and fish. What characterizes the patterns is that they contain less animal and more vegetable foods. This is even more true for vegetarian food. The committee concludes that it has been convincingly demonstrated that the recommended dietary patterns reduce the risk of coronary heart disease and stroke. Furthermore, these patterns are associated with a lower risk of diabetes, bowel cancer and mortality everywhere. It has also been convincingly demonstrated that vegetarian diets reduce the risk of coronary heart disease. In conclusion, the committee recommends eating according to a more plant-based and less animal-based diet.

So far our summary of the Good Nutrition Guidelines. Following the committee’s advice, the Dutch Nutrition Centre and the Dutch Consumers’ Association have translated this into practical brochures and books, including the Disk of Five. The readers of ProRun will probably have seen or read various things earlier. Nevertheless, we thought it would be a good idea to revisit the committee’s own report, which can be seen as the compilation of scientific knowledge about the influence of food on health.

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Our book ‘The Secret of Running’ is for sale in our webshop. Also available in German as ‘Das Geheimnis des Laufens’, and in Italian as ‘Manuale completo della corsa’.

Read more...