Cycling, Podcast, Racing, Running, Science, Training

Performance, Training Tactics, and Physiology of Cycling and Running in Triathlon with Naroa Etxebarria | EP#61

 September 25, 2017

By  Mikael Eriksson

Performance, Training Tactics, and Physiology of Cycling and Running in Triathlon with Naroa Etxebarria | EP#61

How does a hard bike leg impact your running in triathlon races, and what training strategies can you use to minimise the performance decrements? Naroa Etxeberria, having written her doctoral thesis on the topic, has the answers.

In this Episode you'll learn about:

  • How prior cycling impacts running performance-wise and physiologically
  • Attributes that improve running performance after a hard bike leg
  • What type of training you should do to minimise the impact of the bike leg on your run


About Naroa Etxebarria

02:04 -

  • From Basque Country, Spain, where she got her undergraduate degree
  • Got into sports physiology in an exchange program at UK
  • Master’s degree in Loughborough, UK, where she started to work with British Triathlon
  • Worked for a year at the Australian Institute of Sport
  • Went back to Loughborough for a couple of years to work for the English Institute of Sport
  • Assistant Professor at the University of Canberra for 8 years now, teaching undergraduate students, supervising research students, and doing some applied research together with different organizations.
  • Worked with athletes like Tim Don, Stuart Hayes, Vicky Holland, Will Clarke, Alistair and Jonathan Brownlee

How prior cycling impacts running performance-wise and physiologically

06:51 -

  • Physiological assessment of isolated running does not directly replicate running capacity after triathlon-specific cycling​​​
  • The capability of the athletes when it came to the running stage in triathlon is not the same as when they were fresh.
  • An very fit and efficient cyclist will not accumulate too much fatigue, so their running off the bike is very similar to their running when they are fresh.
  • Some other athletes find that the cycling part of the race is demanding, maybe because their fitness during the cycle section is not quite as good as on the run. They suffer the consequences of that cycle section on the early stages of the subsequent run.
  • It’s an art when you are coaching in getting the best performance out of an athlete to balance out how you prepare them for the cycle section and also how to minimize the fatigue that will come from going to the run.
  • One of the things that athletes should think about is that the harder the cycle section is for them, the harder it is for everyone else. Therefore they can take advantage of making the cycle section quite hard and fatiguing their opponents for the running section.
  • A lot of really good triathletes have used this strategy in order to maximize their chances to win.
  • The planning of a triathlete and the training intervention that goes to make the most of what they have is to maximize their strengths but also work hard on their weaknesses.
  • It’s important also to think of how the tactics of the race play an important role and knowing how to make the most of the race situation so that you would benefit from your strengths.


  • "Physiological assessment of isolated running does not directly replicate running capacity after triathlon-specific cycling"
  • Submaximal incremental run test, under three conditions: no prior exercise and after a 1 h cycling trial at 65% of maximal aerobic power with either a constant or a variable power profile.
  • During cycling, pulmonary ventilation (22%, ±14%; mean; ±90% confidence limits), blood lactate (179%, ±48%) and rating of perceived exertion (7.3%, ±10.2%) were all substantially higher during variable than during constant power cycling. At the start of the run, blood lactate was 64%, ±61% higher after variable compared to constant power cycling, which decreased running velocity at 4 mM lactate threshold by 0.6, ±0.9 km · h(-1).

Cycling ability of triathletes

17:12 -

  • Athletes who are not natural cyclists per se can benefit a lot from improving their technical skills so that they can reduce the physical effort they need to put in during the cycle leg.
  • There is a great chance to get at the front of the pack at the end by having better technical skills on the bike. As a result, you would have fresher legs at the end of the cycle leg compared to for example, someone who has a significantly higher power output.
  • This can be useful in non-draft racing long course triathlons as well.
  • Also, work on your swim to exit further up the field because if you’re a back or mid-pack swimmer but a strong biker where you overtake people a lot of times, you’re burning matches and your cycling power output is much more variable than if you are at a much clearer space further up the field after the swim.
  • Even though you may think that the swim is just a short portion of an Ironman and that you don’t need to work on it, you can save a lot of energy this way and be fresher on the run if your swimming is up to quality.

Cycling attributes that enhance running performance

20:18 -

  • As the triathlon race venues were changing, the actual demands of the sport were changing as well.
  • We wanted to see what the actual demands were by making the athletes cycle through short and very high intensity efforts of different durations for an hour before they went to do the run.
  • We found that the physiological demands of a stochastic type of exercise is much higher than when you’re exercising in a steady state.
  • Some athletes are genetically better at variable intensities than others are. But, there is a lot of preparation that's needed to make someone good at variable intensity exercise.
  • One of the aims is to inform coaches as to what the physiological demands of racing were so that they could adjust their training strategies to accommodate the demands of the race.
  • If we don’t know what is actually happening and what the demands of those specific races are, we cannot prepare an athlete to be best at that type of race.
  • The more you can prepare for a stochastic exercise, you can get a better result than someone who does not have the capacity to do that.
  • The physiological adaptations that you get from training is a result of the type of training that you do and the type of stress that you place on your body.
  • Instead of doing a steady state type of training session, try to stress the anaerobic lactic system which is the maximum aerobic power that you can produce in a short period of time and teach your body to recover from it.
  • Doing short recovery intervals between the efforts will get your body to be better prepared to cope with those demands.
  • An example of this is doing 400 meter efforts with only a few seconds of recovery. This is a good way of stressing the anaerobic system and improving at going hard and high.


  • "Cycling Attributes That Enhance Running Performance After the Cycle Section in Triathlon"
  • Cycle VO2peak and maximal aerobic power (MAP) test and a power profile involving 6 maximal efforts (6 s to 10 min). Each subject then performed 2 experimental 1-h cycle trials, both at a mean power of 65% MAP, at either variable power (VAR) ranging from 40% to 140% MAP or constant power (CON) followed by an outdoor 9.3-km time-trial run. Subjects also completed a control 9.3-km run with no preceding exercise
  • The 9.3-km run time was 42 ± 37 s slower (mean ± 90% confidence limits [CL]) after VAR (35:32 ± 3:18 min:s, mean ± SD) compared with CON cycling (34:50 ± 2:49 min:s). This decrement after VAR appeared primarily in the first half of the run

What type of training you should do to minimise the impact of the bike leg on your run

33:10 -

  • We compared longer, more traditional 5-minute intervals with shorter and sharper 10-30 second efforts at higher intensities.
  • Both interventions proved to be beneficial in order to improve performance.
  • We found that the longer efforts got better outcomes for the running. The shorter ones helped with the cycling as well as the running performance, but not as much as longer efforts on the run performance side.
  • What to do really depends on the person that you’re working with.
  • Athletes should look at their abilities and measure what they can do. Then manipulate their training intervention to increase the capacity that they are lacking on.
  • For example, if I have someone that is a diesel type athlete who goes well on a steady state condition, I would probably approach the training intervention by using short and sharp 10-30 seconds efforts because that’s what they are known not to be good at. This is the area where we can improve the most.
  • If you take someone that is really good at doing short and high intensity effort, more of that type of work can only get him a little bit better. While if you do something that they are not that good at, the options and the room for improvement is greater.
  • It’s a good idea to make someone train in a different way that they haven’t done before because the way the body adapts is always going to be better at doing something that they are not used to.


  • "High-intensity cycle interval training improves cycling and running performance in triathletes"
  • Compared long high-intensity interval training (LONG) (6–8 × 5 min efforts) or short high-intensity interval training (SHORT) (9–11 × 10, 20 and 40 s efforts) HIT cycle training.
  • Both groups had an ∼7% increase in O2peak (SHORT 7.3%, ±4.6%; mean, ±90% confidence limits; LONG 7.5%, ±1.7%). There was a moderate improvement in mean power for both the SHORT (10.3%, ±4.4%) and LONG (10.7%, ±6.8%) groups during the last eight 20-s sprints. There was a small to moderate decrease in heart rate, blood lactate and perceived exertion in both groups during the 1-h triathlon-specific cycling but only the LONG group had a substantial decrease in the subsequent 5-km run time (64, ±59 s).

How can somebody find out whether they are a diesel or an athlete thriving on short and sharp intensities if they don’t have access to a lab?

38:09 -

  • I will probably make them go out and put themselves in a race situation and see if they have the capacity to change pace comfortably or not.
  • If you train in a group, you will probably know the one that is very good at leaving the others behind with a few meters to go and everyone else is kind of hanging not being able to change their pace. Then you would be a diesel type.
  • Those people who are very good at the maximal capacity, they might struggle to keep up with those that sustain a high intensity for a longer period of time.
  • The good news is that you can improve in any area that you are not good at. It’s just a matter of working on it.
  • Everyone tends to train what they like or what they are good at. It’s hard to make yourself do training sessions that you don’t like or that are really hurting. Those are the sessions that are actually good for you.

Final tips from Naroa

41:37 -

  • It’s really important to know exactly what races you are preparing for. It’s often quite hard to be able to prepare for different distances within a season. So it’s important that you have a clear goal.
  • It’s also important to be able to have downtime in training, especially in harder periods where you are overloading.
  • You actually don’t adapt from the exercise that you do until you allow the body to rest and recover from it. It’s not the person that trains the most who is going to adapt from it the most.

Rapid-fire questions

Favourite book, blog, or resource related to endurance or high-performance sports or your field of expertise:

  • Different magazines, conversations with colleagues, ITU website, anything that comes into my inbox from the network that I developed over the years

A person in triathlon or in your field of expertise that you look up to:

  • Ben Bright, Mark Pearce, Dave Martin, David Pyne

Research topic you're most excited about:

  • ​Gut health/permeability in athletes, nutrition

Links, resources and contact

Links and resources mentioned

Connect with Naroa Etxebarria

Connect with host Mikael Eriksson


Hi! I'm your host Mikael,

I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.

I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show. 

I sincerely want you to contact me to

  • Send me feedback
  • Give constructive critic​ism 
  • Request topics and guests for the podcast
  • Send me your triathlon-related questions 
  • Tell me that you've rated and reviewed That Triathlon Show so I can give you a shout-out on the show and tell you how much it means to me!
Subscribe to That Triathlon Show and never miss an episode!

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.

Please contact me if you have feedback on the podcast or want to make suggestions for improvement or send in a question for a Q&A episode.

If you are a long-time listener and appreciate the value the podcast brings, please consider taking a couple of minutes for leaving a rating and review on iTunes/Apple Podcasts, or wherever else you can think of leaving a rating and review.

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Explore our products and services