Cycling, Podcast, Running, Training

Pieter Rijnders | EP#390

 May 15, 2023

By  Bernardo Gonçalves


Pieter Rijnders - That Triathlon Show

Pieter Rijnders is a Belgian running, cycling and duathlon coach. He has worked with athletes at the highest level, including top duathletes Arnaud Dely and Maurine Ricour. In this interview we discuss Pieter's perspectives on training and coaching, and dive deep into specifics about duathlon training.   

In this episode you'll learn about:

  • Pieter's approach to training and coaching
  • Going into the weeds on duathlon training specifics (volume, intensity, key workouts etc)
  • Specific examples of training weeks of world-class duathletes Arnaud Dely and Maurine Ricour
  • Transfer effects between run and bike training
  • Training according to muscle fibre typology
  • Top tips for amateur athletes and time-crunched athletes

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Pieter’s background

03:24 -

  • My name is Peter Denders, and I live in Belgium near the Netherlands border. 
  • I have a master's degree in physical education and sports sciences from the University of Leuven in Belgium. I am a part-time anatomy physiology and athletics teacher and a part-time self-employed coach for ambitious endurance athletes. 
  • I specialize in sports science and have experience in long-distance running and duathlon. 
  • I represented Belgium in cross-country running at the European Championships. 
  • Later, I started cycling and won several duathlon races, including the national championship in the sprint distance. I won a medal at the European Championships and participated in the Powerman World Championships. 
  • After retiring from competitive sports, I spent two years preparing to become a coach. 
  • I have been coaching for the last five and a half years, and my most famous clients are two world-class duathletes, Arnoud Dely and Maurine Ricour. They are both professional athletes in Belgium and have achieved personal bests in running. 
  • Duathlon is often underestimated at the highest level of the sport. 
  • They participated in the Worlds Multiple Sports Championships in Ibiza.
  • Races are shorter to increase their appeal to spectators, especially those watching on TV. 
  • In the past, even non-Olympic disciplines, such as duathlon, changed to fit the Olympic format, which they called the Olympic distance. This format used to involve a 10km run, 40km bike ride, and 5km run, but a few years ago, they cut the distance in half, making it shorter.

Training philosophy

09:47 -

  • My training philosophy comes from my experiences as an athlete and the different coaching styles I encountered.
  • I prefer taking a cautious approach to training as I am co-responsible for my athletes' physical and mental health. When working with an athlete, I take it step by step, starting relatively easily to avoid injuries and overtraining. 
  • I apply this approach, especially with younger athletes, as sometimes being slightly undertrained is better than being overtrained. 
  • There can already be continuous progress with the basic principles and a cautious approach. 
  • I believe in long-term learning and seeing the bigger picture rather than going for short-term success. 
  • I aim to avoid overtraining, injuries, and bad experiences for my athletes. 
  • After I know athletes and see that they respond well to the approach, I loosen the reins a bit more and gradually increase the intensity.
  • I've noticed that many athletes are using intensity-based approaches but not achieving the results they could. 
  • Nowadays, athletes can see what others are doing through Strava and compare themselves to others of their generation. 
  • However, I've seen that some athletes I coach have progressed more than others who use different approaches. 
  • This is because they do intensity training too often, which can be counterproductive. I've also noticed that many athletes who do intense training suffer from injuries and overtraining. 
  • I'm proud that the athletes I coach, like Arnaud De Dely, have not had to skip training due to severe injuries. 
  • In my own experience as an athlete, I found that injuries were not only physically challenging but also mentally taxing and affected other aspects of my life. 
  • It's why I prefer a balanced approach to training that focuses on low-intensity work rather than extreme methods or too much intensity. While this isn't a goal, it's necessary for continuous progress.

Duathlon training: training distribution

18:28 -

  • I work with athletes in both duathlon and running. 
  • Duathlon training involves aligning both disciplines to reinforce each other rather than interfere. 
  • This can be challenging because it requires balancing intensity and base work in running and cycling. 
  • Elite duathletes train for three daily sessions, including running, cycling, and core strength. 
  • Although they do less volume in each sport separately, the weekly training hours are roughly between elite runners and cyclists. 
  • Combining both sports enables athletes to maximize their level in cycling and running. 
  • Basic principles involve combining the best possible key workouts with enough easy work to establish a good base.

Brick workouts

22:11 -

  • I have noticed that the need for brick workouts decreases with experience. 
  • Brick workouts are mainly for inexperienced athletes to get used to the transition from cycling to running.
  • For inexperienced athletes, I schedule an easy endurance run after an essential cycling workout to pre-fatigue them and then gradually increase the intensity of the workouts.
  • Athletes do more brick workouts if there is a structural problem in the transition.
  • Multiple-format workouts involve multiple transitions and intervals in running and cycling and are mostly done indoors if athletes have a treadmill and indoor cycling trainer.
  • There are sports centres in Belgium that have a cycling track outdoors and next to an athletics track where you can conduct interval sessions with reps on the athletics track and reps on the cycling track.

Example training week in preparation for the World Championships

26:12 -

  • Their training programme, in preparation, began with easy running and cycling sessions lasting 50 minutes and 2 hours, respectively. 
  • The second day involved cycling in the hills of Denia, Spain, and staying in a hotel with an altitude room for "training low and living high." 
  • The third day began with a pre-breakfast jog followed by a key cycling session with uphill maximal and submaximal sprints and zone two training. The day ended with an easy run for active recovery.
  • The fourth day was a recovery day with an easy ride and endurance run. 
  • The fifth day was another easy run, a strength session, and a long bike ride for three hours. 
  • On the sixth day, the key session was on the bike with a HIIT session. The workout involved a set of intervals with increasing intensity but decreasing duration, conducted uphill. 
  • The day ended with a running recovery session. 
  • Doing morning jogs helps reduce stress and anxiety, leading to a race day, and increases overall training volume.

Training volume

37:06 -

  • I plan sessions based on periodization and buildup to fit into the bigger picture for the season. 
  • For this particular week in the training camp, they ran more than 130km, making it the heaviest week of their buildup. 
  • Similarly, for cycling, volume varies, and in this particular week, the cyclists covered more than 500km, but they usually range from 300 to 500km.

Key workouts

38:32 -

  • During the first week of training, only one cycling session focused on maximum lactate steady state and critical speed or power. 
  • There were recovery days included, especially after road races. The first hard running session was on the eighth day of the second week. 
  • In the second week, there were two hard running sessions and one hard cycling session, all consisting of different domains. 
  • We work with efficiency duration curves to enhance training adaptation by recruiting different fibre types. The body's strategies were considered for this training and adaptation planning. 
  • Power duration curves for cycling were also utilized along with other important similar curves. 
  • The goal was to compose speed duration curves for different distances, such as 5km, 3km, 1500m, and 10km.

Muscle fibre typology

42:18 -

  • The body recruits muscle fibres, including slow-twitch fibres and faster fibres. 
  • Understanding the typology and composition of muscle fibres can be advantageous in creating training schedules. 
  • As a coach, it's essential to have a scientific understanding of muscle fibres while having certain principles to translate that knowledge into training practices. 
  • Slow-twitch fibres have more oxidative properties, recover faster, contain more oxidative enzymes, and are more efficient over time. They can burn more fats and spare glycogen, making them better at consuming lactates. 
  • Despite their name, slow-twitch fibres can manage a lot of tension and produce energy.
  • The research shows that elite athletes can produce a lot of energy without their bodies needing to shift lactate to the bloodstream due to their large number of capillaries and mitochondria. 
  • So, why not maximize this ability by training the most oxidative fibres at their maximum capacity to deal with lactate intramuscularly rather than shifting it to the bloodstream?
  • Training at low lactate levels is efficient for most oxidative fibres. 
  • It can help improve their ability to deliver work, allowing athletes to reach higher speeds or power with lower blood lactate levels. 
  • This type of training is less stressful for the central nervous system and allows for a training intensity distribution that favours easy work. 
  • However, many athletes may initially find this training too easy and lack the patience or confidence to maintain it. 
  • But, if athletes can trigger their type-1 fibres and recover well, they can train more frequently without feeling tired.

Lactate training

50:56 -

  • We should determine the athlete's upper limit for easy work based on their lactate levels, close to the minimum lactate point or LT1. 
  • The LT1 is where the curve rises, usually close to the first inflexion point, although this may not always be present. 
  • Athletes with well-balanced physiology and who work longer widths often have lactate levels around 1.4 to 1.7 mmol, a reasonable upper limit for easy work. 
  • Training close to this limit can activate oxidative fibres before the body switches to more glycolytic fibres, increasing blood lactate levels. 
  • To avoid this, targeting fibres that can deal intramuscularly with lactate buildup, such as type one fibres, is recommended to stay below this intensity. 
  • For elite athletes, it may be best to stay slightly below the LT1 to train at these intensities daily. 
  • Elite athletes have a long flat baseline, and there is a lot of playroom below the LT1. 
  • Arnaud Dely, for example, trains at a pace of 3min15 to 3min10 per kilometre at this intensity, with lactate levels usually around 1.5.
  • It may look like there is only one zone below the LT1 (recovery zone), and then zone two would be a large spectrum, but I think it's rather a small range of intensity.
  • The first zone is the absolute recovery zone, while the endurance one and endurance two zones are for longer and faster workouts, respectively. 
  • Zone two is the extensive tempo zone, just below the lactate threshold 1 (LT1). 
  • Teaching the body to recruit the most oxidative fibres can maximize an endurance athlete's ability to sustain high intensity before shifting to glycolytic fibres. 
  • Inigo San Milan conveys this concept with zone 2, around 1.5-1.6 mmol of lactate. 
  • In scientific literature, the Henneman size and orderly cycling principles indicate that elites are better at switching between muscle fibre groups and motor units to maintain a certain intensity than recreational athletes.
  • Recreational athletes tend to shift to more glycolytic dominant fibres, so they must be cautious with the intensity of zone 2 and LT1.
  • There hasn't been enough research on the maximum potential of type 1 fibres.
  • The focus has been on high-intensity interval training, threshold training, and power and speed training.
  • These training forms and intensities are essential in a balanced training structure, but I have a different approach.
  • Structural adjustments occur at lower intensities but only occur in the long term. This is in contrast to the fast adaptation pathways of faster fibres.
  • Research on lower intensities is complex because it takes months to see the body's structural adaptations.

Muscle fibres and training

1:02:13 -

  •  I am cautious with the volume of training for predominant type two athletes. 
  • To assess their explosive capabilities, I have them conduct a submaximal effort in combination with the first part of the tests. 
  • These athletes have fewer type one fibres, and their capacity to maintain work is limited as they are depleted faster in glycogen, and the body shifts faster to their type two fibres.
  • While they can adapt well to intense work, avoiding injuries and overtraining is challenging when doing a lot of intensity and volume. Therefore, I plan shorter reps and more accessible training for these athletes than type one. I use intake conversations, training history, and performance to evaluate athletes' capabilities.

Other testing procedures

1:04:19 -

  • I work with high-level athletes who undergo testing at a university lab for VO2 and VCO2 levels and ventilatory thresholds. Although I purchased a portable VO2 device for field testing, I lost money as it did not work well and I would not recommend it to other coaches or athletes. 
  • While I considered purchasing a VO2 Master, it lacked VCO2 measurements and was not practical. 
  • As a coach, providing quality testing for my clients and athletes is important, and reliable equipment needs to meet those standards. 
  • After testing the device on myself and finding it unreliable, I gave it to a scientist at the University of Maastricht researching VO2 analyzers. 
  • He found the Pnoe device to be the worst of all of them, and I was not surprised. He is currently researching oxygen analyzers and integrated the Pnoe device into his research after I sent it to him.

Lactate testing procedures

1:10:28 -

  • I prefer to conduct most of my tests on a track, including lactate field tests. 
  • I conduct around 200 lactate field tests annually, an average of four per week. 
  • When working with athletes who live far away, I send them a protocol and a form to complete, and they provide me with the data and results, which I then process.
  • I like to input all the main findings and data into a database on my computer.
  • I always start working with an athlete by conducting initial lactate tests and then doing another one three to four months later to compare my approach and see the influence on the lactate curve of the particular athlete.
  • I work with dozens and hundreds of athletes and compare their race performances with the lactate curve.
  • I conduct running and indoor cycling tests on the track for practical and safety reasons.
  • Athletes use their bikes, power meters, pedals, and shoes when conducting cycling tests.
  • I do not have any problem conducting indoor cycling tests as there is not much difference in biomechanical patterns compared to outdoor cycling.

Transfer effects between different disciplines

1:14:45 -

  • Integrating running and cycling can be beneficial for both cyclists and runners. 
  • On the social media platform Strava, famous pro-cyclists like Wout van Aert sometimes run in the morning before cycling training later in the day.
  • Running can be a healthy way to maintain bone density, and it's time-efficient to train fast and activate the body.
  • The variation in training can activate fat oxidation, warm up muscles, and make the main session later in the day feel smoother. 
  • However, runners need to be cautious because running can put more tension on connective tissues and tendons.
  • Runners can increase their training duration weekly by integrating cycling sessions, especially the day after a hard session or a race. 
  • Combining running with cycling helps runners progress without risking too many injuries. 
  • Cycling interval sessions can stimulate the cardiovascular system to a greater extent or at higher intensities way sooner in the rebuild process when planning cycling sessions than running sessions.

Training for a time-crunch triathlete

1:21:58 -

  • When considering the optimal training for a large group of athletes with limited time due to work and family responsibilities, the intensity and timing of periodization should be considered alongside the athlete's goal and history. 
  • Generally, around 80-85% of the training time should be spent in the intensity range up to zone two, with long, easy training sessions as a cornerstone of every approach. 
  • It's also beneficial to combine this with short sub-maximal bouts in the zone two range after a good warm-up, stimulating faster fibres without producing too much lactate. 
  • When athletes perform these sessions on a track, the coach can monitor their lactate levels and note a rapid lactate clearance after the zone-two interval, indicating lactate clearance capacity correlates with VO2 kinetics. 
  • In athletics, high-intensity training is referred to as sprint interval training, with 100-400 meter reps used as terminology, unlike cycling, where it's challenging to determine zones due to fewer races of specific distances.
  • A typical running session begins with a good warm-up: a few minutes of easy running, followed by 8-10 minutes at a moderate pace to activate type 1 muscle fibres and stimulate blood flow. 
  • The central part of the session includes five bouts of 20-25 seconds at submaximal intensity, with a 1:3 work-rest ratio, followed by short rest periods to elevate lactate levels before consuming it in zone 2. 
  • We should vary the length of the reps based on periodization, starting with short reps and gradually extending the duration, and adjusting the work-rest ratio accordingly. 
  • I recommend one more demanding session per week, with the intensity depending on the athlete's goals and distances. 
  • We need to look at the speed-power-duration curve for the higher-intensity session because it is essential to maintain efficiency at different intensities. 
  • For elite athletes, I usually plan short reps close to the upper limit and work towards extending the fractional utilization of that limit.
  • The overall structure of the training includes a combination of short, high-intensity sessions, one longer, easy session, and easy sessions in between.

Training for time-crunched duathletes

1:32:54 -

  • My approach to recreational duathletes' training programs differs from that of professional athletes.
  • Most recreational duathletes do not require tough weekly sessions in both running and cycling.
  • The longer duathlon races are more popular. My goal is to help them finish the toughest duathlon race in the world, which is also the national championship long-distance cross duathlon here in Belgium.
  • I plan a lot of easy endurance intensity work for running and cycling with a gradual buildup of volume and only short bursts of high-intensity work.
  • I believe that intensity is not the most crucial factor for recreational duathletes.

Three pieces of advice to athletes

1:35:05 -

  • We should approach training in a patient, consistent and gradual way. 
  • Giving your body time to adapt to training sessions is essential, which should not add stress or demand further energy. 
  • We should structure training with incremental increases every two to three weeks, drawing confidence from little steps. It helps if we have an open mind and seek out reliable sources of information to help avoid injuries and overtraining. 
  • However, it is essential to be sceptical of information found on the internet and only to trust experts in the field.

Rapid fire questions

1:38:19 -

What is your favourite book or resource related to endurance sports?

The Science of Winning: Planning, Periodizing and Optimizing Swim Training by Jan Olbrecht
it's a bit outdated but still very interesting with much information about periodization and different workouts.

The Science of Running: How to find your limit and train to maximize your performance by Steve Magness

I'm a fan of collecting scientific articles and publications.
I print them and put them on a to-do read list.

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

The tendency or the habit to being systematic and structured in thinking and working allows me to keep a certain overview over longer periods.

Who's somebody that you look up to or that has inspired you?

My uncle. When i was younger, he took the Belgian record on the marathon: 2h10. He also qualified two times for the Olympics in 1976 and 1980.
He was an elite runner (27min48s in the 10km). He started only running at 18 after being a football player, and a few years later, around sub 28 at 10km.
He was part of what we call in Belgium "The Golden Generation of Runners" here. They had a famous coach that made them do strict intervals on an athletics track, trained in the region with many hills, and did hill sprints. However, now they admit it was way too intensive.


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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