Podcast, Science and Physiology

Power profiling, critical power, and U23 cycling research with Peter Leo | EP#319

 January 3, 2022

By  Bernardo Gonçalves


Peter Leo - That Triathlon Show

Peter Leo is an applied exercise physiologist and high performance coach from Austria. Peter has done extensive research in profiling performance and physiological characteristics of U23 cyclists which we discuss in this interview. We also discuss power profiling and using Critical Power.

In this Episode you'll learn about:

  • Best practices for power profiling (e.g. formal testing vs. raw training data) and methodological considerations
  • What is Critical Power, and why use that as a main physiological marker over others (such as MLSS and FTP)
  • Power changes in U23 cyclists across a season
  • How training characteristics (e.g. training intensity distribution as well as added load from racing) impacted the change in power profile across the season
  • Practical takeaways from these studies - what can we learn when thinking about how we go about our own training and racing across an entire season? 

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Peter's background

03:39 -

  • My name is Peter Leo, and I am from Austria (Tirol). We had the 2018 World Championships in Innsbruck.
  • I graduated from the University of Innsbruck, so I also know the "Tour of the Alps" as a spectator. In 2007, we received one of the last stages of the Giro d'Italia.
  • I have always been in the heart of the Alps.
  • I have a background in triathlon. I was a competitive triathlete at a national level.
  • Now, I am more involved in cycling, but I also focus on triathlon. (as a coach and as a sport scientist)

Peter's PhD investigation

04:50 -

  • Due to commitments with an under 23 development team, I was curious about the physiology and performance requirements. (in this category)
  • There was a deficit in research in this area. We had good studies from junior cycling, and others did studies in professional cycling.
  • In 2018, there was a gap between the junior and professional levels.
  • It led me to pursue a PhD in "Longitudinal and Physiological Performance Characteristics in Under 23 Cyclists".

Cycling power profiling

06:35 -

  • As an athlete, I was interested in this topic a lot. I worked for the SRM Team as an intern in the 2015 Tour de France.
  • We analyse performance data at that time. It was my first contact with using power output as a guide to explain endurance performance.
  • As my studies developed, I got more and more into the topic. And it led me to the critical power concept and the different methods of accessing it. There are various ways of doing them that bring some debate in the scientific community.
  • The one we present might be the correct one, but we tried to provide a robust framework of the underlying physiology. (and linking it to endurance performance)
  • There is some misconception around power profiling. It is not only uploading a training file to the software and getting a power duration curve. It does not explain the physiological performance information.
  • Therefore, it is crucial to use some "formal" testing. (standardise testing)
  • Rather than guessing information based on training, you should have a clear idea of different field and lab tests. You need to understand what you will test in the field and the lab. Then, you can analyse how this information correlates with your training and racing.
  • I am not the person who can program and understands technology in depth. I can only do my basic analytics with some simple coding.
  • There is a lot of conflict in fields combining people from different backgrounds. (engineers, mathematicians and data analytics combined with sports scientists)
  • They can produce different models, but often people forget that they are modelling human physiology. Therefore, you have to connect the external factors with the physiologic responses. But often, that connection is lacking in performance models.
  • Thus, we work with them to explain power output's impact on human physiology.
  • The critical power model is the most studied bioenergetic model to describe the physiology and the different intensity domains.

Critical power testing

13:15 -

  • Many researchers know more about critical power than I. (Andy Jones, Mark Burnley, Philip Skiba)
  • When doing a critical power test, we need to understand the population characteristics.
  • With non-experienced athletes, you need at least four or five critical power tests to get accurate data. (they are not used to going all out)
  • When you have world-class athletes, you can reduce the number of efforts to have an accurate model. Mehdi Kordi's paper showed us how to approach these populations.
  • The test segments selection must be careful. All tests should be in the severe intensity domain.
  • It means they should achieve VO2max in a lab. This information leads to a narrowing window to perform testing.
  • Some papers state that you can only achieve VO2max after two minutes. The tests can be up to 15 minutes. Therefore, you have this window where you can do distinct testing.
  • There is some common sense that the tests should be between five and seven minutes.
  • When I was working with cyclists, first, we would do two, five and twelve minutes. The reason is we used the same procedures as in the lab.
  • Then I followed Louis Passfield protocols of three, seven and twelve minutes. I have never done it with 15 minutes.
  • Ten minutes for the lengthiest test can be too short.
  • The shortest ones are between two to three minutes.
  • You might want to maintain the same protocol. It is better to fix one protocol and apply it constantly. You should also choose the best climb. All these tests are climbs, between 4-7%.
  • In a lab, you put a power output. And you measure the time you can hold it. It is a time-to-task failure.
  • Outside, you give time duration, and you tell athletes to go all out for that duration.
  • However, to compare results, you should always use the same protocols.
  • Moreover, we have a natural variation in Critical Power. It is not a static value. It means that if a test gives you a CP of 380 W, you might be in a steady state between 370 and 390 W.
  • Critical power is more a phase transition than a threshold. (it depends on the day and motivation of the athlete)

Applying the best testing protocol

20:13 -

  • The period to do the test is fundamental because the athlete needs to be motivated and ready to do the test.
  • The athlete needs to reduce training volume before the test, do some activations and a standard warm-up.
  • I would do these tests always in February in the training camps.
  • We are all together and use two days of testing.
  • The athletes are always motivated at that time because they want to race.
  • It is not a good idea to do it too early in a season. The athletes have to build their fitness a bit before doing these tests. The higher their performance level, the more difficult is to go all out.
  • Therefore, you should do it only sometimes to have accurate data.
  • You have to be aware of the weather conditions. So, avoid any extreme temperature ranges. Moreover, you have to consider the altitude where you perform the tests.
  • We perform the tests over two days: the two shorter ones on one day and the other on the next day. However, we randomise the tests to evaluate the best protocols to use.
  • In one attempt, we let athletes choose individually. And different athletes chose the tests in a distinct order.
  • Sprinters would want to do the shorter tests first. The order of choice was something we did not test, but it was data we gathered while I was there.
  • For coaches, athletes need awareness to perform these tests. There is a learning curve about doing a critical power test.
  • Therefore, you need one or two CP tests to make it accurate.
  • Many studies addressed its use on moderately trained athletes. There are some limitations when applying it to this group.
  • CP works well in professional cyclists. For moderately trained athletes, it is better to do it in a lab.

Issues with CP field testing in moderately trained athletes

24:46 -

  • The primary problem is pacing. Therefore, you can control the conditions a bit better in a lab.
  • There are also logistical considerations to perform the tests. You have to find a quiet road.
  • You have to avoid doing it on a busy street because it is dangerous. In the severe domain, you have less control on the bike and less awareness of what is happening around you.
  • As a coach, you have to consider the safety of the athlete. In racing, roads are closed, and these problems do not exist.
  • When we have to do a test, I know exactly where we need to go. I know the quiet roads, and I will see them the day before the test.
  • I do it to avoid, for example, construction works. (you want to avoid stopping 2 km into the test)

Doing a CP test indoors

26:35 -

  • You have to use the Erg mode to have the proper resistance.
  • The problem is with the type of smart trainer you have to do that test. When you do it in a lab, you do it with a Loude, Sram or Monark ergometer.
  • The ergometers have validation in the literature and good breaking resistance.
  • It is also a motivational thing. You have to understand if the athlete can perform indoors or outside.
  • For example, I do not want to do tests indoors. I prefer having two or three trials outside.
  • I did the 3-min CP test. I thought of introducing it to the cycling team. However, it is too painful for cyclists. (that already have to suffer every day)

How to plan critical power tests throughout the year

29:21 -

  • We might come away with only one test per season. (before the first race)
  • Then, with the information we got from racing, we observed changes in the data. The reason is because of changes in body mass (riders get lighter due to more racing stress and training volume)
  • The two/three kilos lost might affect power output. Throughout the season, we saw an improvement in relative power output. But we saw no difference in the absolute power output.
  • However, it is still a performance improvement. The relative power improvement is advantageous for climbing terrain.
  • We understood we needed to add another half-season test. (after the first part of the season - end June/early July)
  • We thought it was an appropriate time after a solid four to six weeks of racing. And we would also have good indicators before the second half of the season.

Why test critical power instead of MLSS or an FTP test

31:15 -

  • Concerning the physiologic aspect, you get some info when you use critical power or MLSS.
  • However, I am careful about talking MLSS because there is debate about the highest metabolic steady state.
  • You can use CP as a top-down approach. (you get the border between the severe and heavy domain)
  • And then, you can use MLSS to obtain the frontier from the "heavy" and the "severe domain".
  • Some data I have not published yet is related to CP and MLSS. The higher the athlete's fitness is, the closer CP and MLSS are to each other. (differences of 10 to 15 W)
  • The above mentioned is the physiological perspective for the transition between steady-state and non-steady-state exercise.
  • On the other hand, we refer to time to exhaustion with one single test. (e.g., 20-minute test)
  • It gives only one point on the power duration curve. And we know the power duration curve is second by second. Therefore, you need multiple points to trace it.
  • It is the reason to use at least two tests and CP tests.
  • However, we should do more tests to obtain a better fit between measurements. If you do not do more than two tests, you can not apply a hyperbolic/non-linear relation between power and time.
  • With those tests, you get the work above CP. (W') And the second component is CP itself. With these two parameters, you can characterise the intensity domain.
  • Therefore, you can prescribe training in that domain based on time to exhaustion. You can estimate a 5/7/8 minute all-out effort.
  • This approach has its limitations. A two-parameter model underestimates short duration power output production and long power output sustainability.
  • However, it gives a more concise characterisation of the underlying power duration relationship.

Limitations of the critical power model

37:10 -

  • The anaerobic power is a more appropriate scaling model for track cyclists. (short-duration efforts)
  • It is essential to understand each model's limitations. However, do not get obsessed with too much modelling.
  • You still get a lot of information from the training process itself. (with some standardise intervals or athlete feedback)
  • You want to avoid focusing too much on the models. You have to focus on other crucial components. (nutrition, motivation, environmental conditions and others)
  • You have to be aware of how to use it. But you also have to know its limitations.

General tips about power profiling and critical power

38:35 -

  • If you approach CP testing, select the time to test wisely.
  • It should be close to the start of the season: it is where you get accurate measurements.
  • Use at least two or three prediction trials, and be aware of familiarisation with the protocols beforehand.
  • The recovery time between efforts should be at least 30 minutes. It ensures adequate recovery between tests.
  • Use a standardise climb for the tests, check the traffic or road works before the testing day.
  • Consider outdoor conditions like temperature, altitude and humidity.
  • To analyse data, plug it in excel or use other apps that give the critical power data and the standard errors.
  • Felipe Mattioni gives open-source information about lactate and the CP models that I use.

Power evolution in under 23 cyclists

41:07 -

  • This study was a consequence of a CP analysis. (where we were considering the power changes during the season)
  • We did not evaluate the difference between racing and training. (in the other study)
  • Then, we divided efforts in training and racing and compared them to the standard measurements at the beginning of the season.
  • We found power achieved in training were lower than in racing. It is common sense because we do not produce maximal efforts in training.
  • With high-intensity training, the interval does not need to be all-out.
  • We divided the season into three periods: the early season (February-April); midseason (May-July); end of the season (August-October)
  • We evaluated how training in one period affects power profiling in the next period.
  • In the first races of the season, even in athletes training constantly, there was a decline in the power profile.
  • If you do not manage the workload in the early season, you have lower power outputs.
  • And most racing happens in the first part of the season.
  • In these periods, coaches want to maintain training. However, the residual fatigue kicks in and athletes cannot perform as well.

Reasons for performance decreases in the first part of the season

44:27 -

  • This point is something we have been discussing with coaches.
  • We would argue that race planning did not allow athletes to build fitness. Athletes would have races every week and adding more and more fatigue.
  • They do not have the time to absorb that stress to reinforce it in training and build fitness. We observed it throughout the 2018/2019 season.
  • It is a challenge to manage the season because of the racing calendar. The crucial races are all packed in a few weeks. Therefore, the athlete needs to perform in most of them.
  • On the other hand, you want to build fitness over the long term. There is no one size fits all.
  • Some athletes can handle the load. However, the trend is the opposite. Racing more adds more fatigue and more detriment in performance.
  • Team managers see athletes already as professionals. However, they are still in their development phase.
  • The racing program in many of those under 23 teams is too aggressive at the start of the season. (at least before covid)
  • At the end of the season, you are flattening out.
  • Late in the season, we saw a substantial variance in the power profile between riders.
  • The variability was because athletes were going "mad" and losing fitness. Others could maintain it or even improve.
  • The athletes who improved followed a strict polarised modelling distribution. Athletes who accumulated more time below LT1 would also have proper time above LT2.
  • Cyclists that do much time in those "grey zones" would plateau or decline fitness.
  • These observations were handy to understand how different training approaches would affect performance in the end.
  • These distributions include racing because races create stress, and it is that accumulation we wanted to evaluate.
  • Although everyone works for the team, some athletes have more load than others. (team leaders vs domestique riders)

Other findings of the study

49:07 -

  • The training characteristics were the primary findings of the study. (polarised approach is more successful)
  • Be careful when adding more training when you have a high racing density.
  • Check if the athletes are aware of the season length. It is a problem for younger athletes. Everyone wants to shine in the beginning. However, they forget there are crucial races in September as well. (European and World Championships and other primary events)
  • Those races also play a role for World Tour Teams when teams choose between riders. They tell how the rider is progressing and their fatigue ability.

Reason for absolute power plateaus during the season

51:37 -

  • In this study, we saw how dynamic power profiling is.
  • Power profiles of the athletes are from data when athletes are fresh. It is why we did the study on the Tour of the Alps power analysis to evaluate power after some level of workload. World Tour Teams use this race as a build-up to "Giro D'Itália".
  • In Tour of the Alps, we had a unique opportunity. As our team basis is in Tirol and Tirol is a sponsor of the race, we had a wild-card for that race.
  • It is a race where we can face cyclists like Egan Bernal, Geraint Thomas or Thibaut Pinot.
  • For our team, it is an extraordinary experience for our athletes. And for us, it was an opportunity to understand the performance requirements.
  • We had a collaboration of data sharing with other teams. (Androni and Bora-Hansgrohe)
  • First, we looked at the power profile for multiple durations. (from five seconds to 30 minutes) With this analysis, we did not find any difference in the power profile of athletes.
  • There were some variations in the relative power profile. However, the riders selected were climbers concerning their anthropometric characteristics.
  • We know that coaches prescribe sessions also based on the kilojoules of work. Nevertheless, no one has researched that topic before.
  • Therefore, we quantified the work from 1000 to 3000 kJ. And we evaluated the athlete power profile modifications with this.
  • This analysis was where we found the most variations. Under-23 athletes fatigue much faster than world tour riders. After 2500 kJ, their power profile decreases substantially, while professional riders can maintain their power profiles after 2500 kJ.
  • In the second approach, we did sub-divisions of this group based on their anthropometrics. (all-rounders, domestics and GC contenders)
  • From an anthropometric viewpoint, GC contenders and domestics did not differ.
  • We evaluated who had a supportive and a primary role.
  • The top 10 of GC overall standards were top contenders, and the rest were domestics.
  • After the analysis, we see also discrepancies between professional riders for different rider types.
  • Of course, there are other factors to consider when evaluating the races. (e.g., race dynamics, team tactics, race strategy, day to day variations)
  • We are aware of the limitations of the study.
  • However, the power we obtained from the study was quite impressive, and the interest from the scientific community was also significant.
  • There was much interest in that project because a study like this had not materialised before.
  • Another research group did a similar paper with a kilojoule approach during the same period. And they came out to the same conclusions as we did.
  • In research, this situation is ideal for us. (two independent groups showing the same results)
  • It has strengthened our paper, but also theirs. Therefore, we opened the door to something new, and we are now filling that gap.

Under 23 power profile decreases compared to professionals

57:40 -

  • We corresponded the power profile after an accumulated workload comparative to race performance.
  • Race performance is quantified as the UCI points scored or the percentage time difference to the overall winner.
  • In conclusion, you need 5.3 W/kg after 2000 kJ for 20 minutes or longer to get UCI points.
  • It was an impressive marker that I had not looked at before.
  • I presented it at Science and Cycling Conference in Leuven, and some researchers confirmed the results. (they did not publish the data gathered in Mapei, but they get the same data)
  • Even though we have different approaches and methodologies, the findings are robust.
  • The GC contenders that wanted to win a stage race need to do 5.8 W/kg on the average climb in that race. (it applies to win a stage race or fight for a top position)
  • Previously, Tom Dumoulin's single case study found the same results. They concluded that he needed 5.8 W/kg for 20+ minutes after 2500 kJ during Grand Tours.
  • Although we had distinct interests and approaches, the results were solid.

Developing fatigue resistance

1:00:13 -

  • At the moment, we have a problem. We can classify who is fatigue resistant or not. However, we do not know the triggers.
  • Therefore, we do not know the proper amounts of training (both high and low intensity) to explain fatigue resistance.
  • Of course, we are looking at the underlying mechanisms. There is a training aspect to consider and a nutritional as well. (how you take and maintain your glycogen stores)
  • However, I would say this is an integrative approach. You will not find a single component that explains fatigue resistance.
  • It is such a complex phenomenon that the result might be a product of many factors.
  • If you want to be critical of this paper, it does not consider race tactics. We cannot measure lactate/RPE/O2 consumption during races.
  • We do not know the impact team tactics have on power output. Was the athlete's job done? Or was it because he was over the limit?
  • When you look at the Tour de France, domestics leave the pack. Do they do it cautiously? Or do they do it because they cannot hold the pace anymore?
  • It is where your research is going now.

Reasons for lower training volume in late season period

1:03:53 -

  • When we analysed the study, we looked at it in retrospect.
  • We did not want to manipulate the data we collected. Therefore, we did not alter the training data with our insights.
  • We standardised a protocol where we evaluated a team for the whole season. Of course, we developed some standard efforts, but we did not want to influence the training outcome.
  • First, we wanted to use the opportunity to learn about the training procedures so we could improve them.
  • The training volume reduction at the end of the season comes from two reasons.
  • First, I think it is a strategic decision. It is like a season goes with the dynamics of racing and races days.
  • However, I also believe there is a subjective component of the athlete and coach relationship. They could change the season approach because they do not need to be in top shape in April.
  • Therefore, they can gradually build fitness over the season.
  • This year, we had an example of that with Georg Steinhauser. He gradually built up to peak at Tour de L'Avenir and the races after. He had the best season period ever.
  • We learn about this aspect daily. At the time, we did not know, but now we are reinforcing this to make fewer mistakes.

General questions

1:06:22 -

Can you give three pieces of advice to age groupers to improve their performance?

I think it comes down to simple principles: train, recover, eat and sleep well. For endurance sports, I think you only have to follow the basics. And it is the most challenging thing to do. Endurance athletes are obsessed with new technologies and different measurements. (e.g., HRV) And they lose their self-awareness. Therefore, I think they cannot recover as well. There is also much influence on social media. Athletes need to look good on the training rides. (and tell details about training) So, there is much influence that does not let you train well. Going back to the roots, we have to ask: What do I need? The answer is straightforward.

There is also a problem in sports science. Researchers want to sound exclusively knowledgeable. So much they forget to keep things simple. Do not overcomplicate things or explain underlying physiology to athletes. There is no point in boosting your knowledge in public places. Therefore, I think we should be more conservative.

What is one thing within coaching or training you are now learning/curious about or fascinated by and why?

I feel I am always learning. You have to keep learning. And there is not a day where I am not interested in a new topic of sports science. However, I try to refrain from it a bit. I also give myself some time to absorb. It is better to spend a morning reflecting on the work than moving on to a new topic. In conclusion, I am learning more about work/life balance.

Rapid fire questions

What is your favourite book, blog or resource?

Peak Performance: Training and Nutritional Strategies for Sport by John Hawley and Louise Burke

What is an important habit that benefited athletically, professionally or personally?

It is team spirit. Being humble and appreciative of what I do every day are other points to consider.

Who is someone you have looked up to or who has inspired you?

It is my grandparent because I live in the same house as him. I got a renewed apartment there. He is 85, and he is still doing his morning gymnastics every day. He is super fit (20 pull-ups), and he still does skiing.


Bernardo Gonçalves

Bernardo is a Portuguese elite cyclist and co-founder of SpeedEdge Performance, a company focused on optimising cycling and triathlon performance. He writes the shownotes for That Triathlon Show, and also produces social media content for each new episode.

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