Advanced, Podcast, Training

Training Talk: Splicing Workouts, Cognitive Load, and more with David Tilbury-Davis | EP#53

 August 28, 2017

By  Mikael Eriksson

Training Talk: Splicing Workouts, Cognitive Load, and more with David Tilbury-Davis | EP#53

David Tilbury-Davis, coach of, among others Cody Beals and Lionel Sanders, shares fascinating insights about training, including the cognitive load of triathlon, splicing workouts (based on the WHY of your workout), and action steps for how self-coached athletes can get started coaching themselves more effectively. We also dive a bit deeper into bike training specifically.

In this Episode you'll learn about:

  • How to become a more effective self-coached triathlete
  • Splicing workouts to achieve a desired adaptation
  • The cognitive load of triathlon and how it impacts planning your training
  • The 20-minute rule
  • Technique-under-load in swimming
  • How a weekend warrior's and Lionel Sander's bike training in principle is not too dissimilar


About David Tilbury-Davis​

02:15 -

  • I’ve been coaching triathlon for about 20 years now. I started coaching full-time in 2008.​
  • I’ve been working with a mixture of professional and age-group athletes all over the world for many years. Currently, my athletes are predominantly in North America and Canada.
  • Among the professionals, I’ve worked with for example Cody Beals, Lionel Sanders, Lesley Smith, and Sue Huse.

You are known for your scientific approach to training. How does it translate to planning the training of your athletes?

04:07 -

  • You’re not the first person to say that I’m perceived as a quantitative coach but if you speak to my athletes they would probably argue quite differently.​
  • If you’re not measuring, you’re not managing.
  • The depth and detail as to which you measure is dependent on what sort of outcome you are hoping for. The true test of whether you’re doing things right or wrong is a race.
  • The whole point of collecting data along the way is to understand why or why not you’re progressing, and thereby you can learn as coach and as an athlete.

How do you measure? What are the timelines? Do you have periodic tests?

​06:04 -

  • ​It depends on the athlete. In most instances, we’ll sit down at the beginning of the year and we’ll look back at the previous year and look at what went well, and what could have been better. And what are the goals moving forward for the next 6-12 months.
  • Then within this, lay out very clear benchmarks along the way of progression.
  • I also use some fixed tests like a 20-minute or 4-minute test on the bike, or a 400 meters and 200 meters test in the pool to calculate critical pace or power.
  • There’s also the reality with three sports that if you’re constantly testing it can get very cognitively demanding for an athlete.
  • The reality is that training is testing and testing is training.
  • My experience is such that there are certain training sessions an athlete will do that I will expect a certain response. If they’re definitely progressing then the response is X + Y. If it’s not what we’re expecting then it’s X – Y.
  • So there’s a combination there. I’m not as black and white as we must do a 20-minute test every 6 weeks to validate your progression and fitness because the reality is you can write a training program that can make somebody absolutely phenomenally brilliant at 20-minute tests. You could rightly argue that that’s a really good reflection of their aerobic fitness. But if they’re training for an Ironman and the longest bike ride they ever do is 90 minutes, then I think you’re setting up that athlete for failure.
  • There’s some common sense in there in terms of specificity towards a race or the outcome such as a certain run split or a certain power output.
  • A good example is, I’ve worked with an athlete from Espoo, and he raced Ironman Malaysia last year and was looking to qualify for Kona again. Training during September to November in Finland has its challenges. So we had a very large focus in heat acclimation and carefully monitoring the sort of interplay between his power output and cardiovascularly what was going on. As a measure of heat tolerance and using certain heat acclimation protocols to get him ready for the race.
  • This is something that any age-group athletes can do. Sit down and take a SWOT analysis on what are his/her physiological strengths or weaknesses based on their sporting background and how does these relate to his/her goals and what type of race he/she is aiming for. What opportunities do I have to train? What are the threats to my training and its consistency?

Is the SWOT Analysis a good place for the self-coached age-groupers to start with?

13:44 -

  • Yes. The run is a good example where it’s very easy to start to get a sense of being wiser with the intensity that you’re training at.​
  • If you’ve done a couple of running events in the past, even if you’ve done only just one 5k, and you’ve started getting into triathlon, then you can very easily find on the internet e.g. Jack Daniels’ VDOT calculator. It will tell you your endurance, threshold, and interval paces. This is a good starting point and you don’t necessarily need to get more accurate than using something like that.
  • On the bike, if people don’t have a power meter or they don’t even own a heart rate monitor, simplistically you can find a nearby incline that’s going to take around 4-8 minutes.
  • On a reasonably benign day from a weather perspective, just ride up it as hard as you can.
  • This is a very gross simplistic mechanism of laying down a benchmark of, "is my fitness improving?"
  • On the other end of the spectrum, you have lactate testing, critical power testing where you’re doing multiple measures in a lab or with a power meter on your bike and then calculating a very accurate threshold.

Critical Swim Speed and Swimming

  • This is an easy one. There’s the actual original work by Wakayoshi where you’d take a 400 m and a 50 m time trial time, and you subtract the 50 time from the 400 and then divide it by 350 and that gives you your critical pace.​
  • The other way is the more recent terminology of critical swim speed which is a term used by Paul Newsome at Swim Smooth where you do a 400 and a 200 m, and you subtract the 200 from the 400 and divide by 2 and that gives you your critical pace.
  • The swim is an interesting one where you have to be a little bit wary of getting too wrapped up in training the same way that you would train on the bike and on the run. Because I fundamentally do not think that that’s the best way to get the best out of your swim.
  • The reality is that you’re just never going to swim enough as a triathlete to really be driving the aerobic pathways in the same way that a swimmer would be.
  • You really want to start to understand what’s the best way for me to improve my swim based on improving my technique? But improving my technique under load. 
  • Not just doing drills but actually working on acquiring a better sense of the skill you have in the water. Whether that’s using toys or getting feedback from a coach, visual or oral.
  • You can’t separate improving technique and doing it under load. A good example of this is – personally I dislike the persistent use of paddles by triathletes. The reason is that most triathletes have a terrible feel for the water and when you race in triathlons and you’re swimming on other people’s feet, you’re actually catching dirty water that is already aerated. So it’s even harder to get a good catch, a good feel for the water.
  • So, if you put something on you hand that doesn’t actually allow you to have a good feel for the water, it means that your arms move slower through the water at a slower contractile rate than you would typically swim at. This for me seems completely counterproductive to what you actually need to achieve in swimming.

Commonalities among age-groupers that see great triathlon improvements

22:58 -

  • From what I’ve seen with age-group athletes and the professional athletes that I’ve worked with, the biggest quality that I see in terms of successful outcomes is being very intrinsically motivated.
  • There’s a clear pattern and relationship between the ones that are heavily intrinsically motivated for the sense of achievement, the sense of getting the best that they physically want to get out of their body. They are the ones who are most successful. Combining this with a very open and honest communication about how the training is going, how it felt, but also trying to avoid compartmentalizing life. And this is probably the one mistake that I see many self-coached make. They try to compartmentalize their work, family, and training.
  • The reality is that there’s always wash over in terms of stresses or pressures across all of those. So, to sit there and have a really stressful job, come home and do an intense session goes back to my point on understanding cognitive load.
  • As a coach and a self-coached athlete you need to be able to step back a little bit and understand how does everything interrelate? Do I really have the mental and physical energy to do what I need to do today? Do I need to adapt accordingly because my time is limited or I can’t get to the swimming or I don’t have the mental bandwidth to do that really hard workout tonight but I know that I can do it tomorrow.
  • It’s about making those judgment calls and trying to remain objective about the broader and longer picture of, “Well, in 3 months’ time this is my A-race. I’m going to go and finish that Olympic distance triathlon.”
  • So, adapting today is not a deal breaker. But am I trending in the right direction?
"Adapting today is not a deal breaker. But am I trending in the right direction?"

Where do you draw the line whether you have it in you to do a hard session today or if you should skip it?

26:05 -

  • For the bike and run, I would always encourage athletes to go with the 20-minute rule of starting the workout and give it 20 minutes and really see how you feel. And you may well find that actually, the intensity of the workout becomes almost meditative and cathartic.​
  • This 20-minute rule comes from experience of working with many elite athletes. It’s at about the 20-minute mark where things really start to kick in.
  • For the swim, I would still say 20 minutes but I encourage people if you have a workout where you’re just struggling to hit your times to look at the workout and ask yourself, “What am I actually trying to achieve here?” And if I’m doing 10 x 100s quite hard and I’m just not hitting my times, maybe I’ll break that up into sets of 50s, and I give myself enough rest so that I can cognitively reset so that I can hold my stroke together.
  • The reality is that what you are constantly chasing after in the swim is being able to focus on holding your technique together under load for the longest period of time.

Do you any overarching principles when it comes to bike training for triathletes?

29:48 -

  • There’s a couple of aspects in there. I think it’s understanding the demands of the race.
  • It’s important to pay attention to the little details of where is this course? For example, if I live in Florida and it’s pancake flat and I decide I want to go and do Ironman Nice which has a gigantic mountain in it with a technical descent. Then, I really need to try and work out and understand how I prepare for that from a muscle recruitment perspective. And that may mean you need to do a certain style of strength-based intervals. Maybe joining a local cycling club and doing some criterium racing.
  • And it's about building a program around that. Understanding from a neurological perspective how you improve efficiency.
  • Is there a particular demand for overcoming anxiety around technical descending? How do we address that? Do they have an issue with riding at a really high speed? Do they need to do certain strength and conditioning works to cope with being really stable on the mountain bike whereas the bike is moving around underneath them?
  • I always find it interesting when I hear triathlon coaches say, “You don’t need to do any strength and conditioning work. It’s a waste of time.”
  • If you look at world-class athletes across multiple sports, they are constantly doing some form of conditioning work because you need a stable base to express power.
  • Try to be super consistent with the training that you do. Find that consistent balance.
  • In the main, stay away from that middle ground because a lot of athletes make the mistake of just doing way too much upper tempo and low threshold work. It's super expensive to recover from. That's why when you look at Stephen Seiler's work there's this clear evidence of polarised training. It's easier to recover from that higher intensity than the middle ground.

How would a beginner triathlete that has done a couple of races, training 6-7 hours per week, maybe 2 rides per week, train on the bike?

​37:02 -

  • The first training session they should do should be predominantly aerobically oriented like an endurance ride. But within that endurance ride, I’d encourage them to really work a variety of different cadences.​
  • If you’re trying to improve the body’s ability to express fitness, then you would want to learn for your body to operate at different muscle contractile rates. So, riding rolling terrains and riding at different cadences and keeping the intensity predominantly aerobic would be a good starting point.
  • The second session is maybe where you do some very short hard intervals. Somewhere between 8-16 minutes of total work. And you would slice that up as a 2:1 ratio. So if you’re doing 8 minutes of work, you get 4 minutes of recovery. 

On the other hand of the spectrum, what would you do for somebody like Lionel Sanders who is a pro and one of the best in Ironman racing on the bike?

39:33 -

  • There’s obviously more sessions and the numbers are larger but the principles are the same.
  • We’re trying to ensure that there’s a resilience against neuromuscular fatigue and there is a high level of fitness.
  • In December last year Lionel and I sat down and looked at where we need to be by about this time next year. We laid out a path of progression. It’s a bit like a coloring book where I sort of put the picture there and it was Lionel’s job to go away and color it in based on what he understands of his body and what I know from both the science and evidence in the field of this is what you need to do to raise your VO2max or threshold. And do it in a way that you can recover from it as effectively as possible.
  • For the athlete, if you’re feeling great today, go do 4 x 4 minutes with 2 minutes recovery. But if you’re not feeling great today and you still need to do 16 minutes of work, then slice it up differently. If you feel like a rock star, you might do that first interval as 6-7 minutes and then the rest will be 3 minutes, 2 minutes, and 1 minute. And that seems to work really well whether it’s Lionel or an age-group athlete.
  • But just putting that autonomy on them to make a smart decision around just how cognitively demanding they make the workout, has allowed Lionel and other athletes to just get the best out of the workouts.
  • So the principles are the same, it’s just that the numbers are obviously larger and anybody who has seen his Strava would agree.

Rapid-fire questions

43:19 -

Favorite book, blog, or resource related to triathlon:

Favorite piece of gear or equipment:

  • ​A camera, like a GoPro.

Personal habit that helped achieve success:

  • Constantly learning and make better and better informed decisions​.

What is the most demanding high-intensity interval session? A paper by Stephen Seiler.

​46:27 -

  • ​Download the paper here
  • How demanding a session is perceived as depends on the work intensity, accumulated work duration, and the work to rest ratio as well as the acute intensity.​
  • A Swedish study back in the 60s came to the conclusion that if you perform a workout at a power or pace that would take you to exhaustion within 10 minutes when performed as a time trial but you break that work up into work to rest blocks with a constant 1:1 ratio but different durations, for example, 1 minute work, 1 minute rest, or 2 minutes work, 2 minutes rest, and so on. You will identify a breaking point that happens between that 1 minute and 2 minute work durations, where to sustain a 1 minute work duration is sustainable for a whole hour which is pretty amazing.
  • But when you increase the duration of work bouts to 2 minutes and increase the rest duration as well to 2 minutes, even though it's the same work-rest ratio and the same accumulated work is in place, it becomes increasingly hard, almost exponentially harder to sustain that and you see the physiological responses as well of that harder effort.
  • Another interesting piece from this paper is a reference to one of Seiler’s own studies with physiological and perceived effort data on over 1,400 individual high-intensity interval training sessions performed by 63 subjects over 12 weeks. These sessions were always one of three prescriptions 4 x 4 minutes, 4 x 8 minutes, or 4 x 16 minutes prescribed as maximal session effort workouts.
  • The data showed that by far, the hardest perceived workouts were the ones with the 4 x 4 minute work durations. They had for example the percent of sessions with a session-RPE of 9-10 (on the session-RPE scale which goes to 10 as maximum) at 32% for the 4 x 4 minute session, and only 7.8% for the 4 x 8 session, and 5.3% for the 4 x 16 minute session.
  • But Seiler makes a good point on that data leading them to conclude that effort and exertion are different constructs and acute exertion seems to be strongly driven by acute work intensity. Whereas effort can be seen as the integral of exertion and time.

Articles and podcast episodes mentioned

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Mikael Eriksson

I am a full-time triathlon coach, founder of Scientific Triathlon, and host of the top-rated podcast That Triathlon Show. I am from Finland but live in Lisbon, Portugal.

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