Podcast, Training

Interval Training – Science and Application part 3 with prof. Paul Laursen | EP#163

 January 7, 2019

By  Mikael Eriksson

​​​​​​Interval Training - Science and Application part 3 with prof. Paul Laursen | EP#163

TTS163 - Interval Training - Science and Application part 3 with Paul Laursen

Paul Laursen is adjunct professor and performance physiologist at AUT, he lead the Performance Physiology Team at High Performance Sport New Zealand for both the London and Rio Olympic cycles, and he coaches several elite triathletes. He is also the man behind HIIT Science (together with colleague Martin Bucheit). In his third appearance on That Triathlon Show, we dive even deeper into all things interval training for triathletes, and discuss practical programming applications.

Discuss this episode!

  • Let's discuss this episode and the topic in general. Post any comments or questions in the comments at the bottom of the shownotes. Join the discussion here!

In this Episode you'll learn about:

  • What is the cost in terms of fatigue, recovery time, overall stress, and injury risk of various types of intervals?
  • How do factors like age, sex, and athletic ability and experience influence interval training?
  • Practical application of HIIT in triathlon programming - what would be some example training weeks for long- and short-course triathletes? 
  • The HIIT Science book and the course.

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Paul Laursen's new book

1:16  -

Reminder of the interval types 

4:02 -

  • Sprint interval training are long sprints - the intensity is all out and it ranges from 20-30 seconds. 

    You need long recoveries between these to calm the metabolic system, generally 2-5 minutes. 

    You get a big response because it's a massive load on the whole body. 
  • Repeated sprint training are shorter sprints (3-10 seconds), all out in nature - not typically used in triathlon but regularly used in team sports. 

    The recovery is also shorter, typically around 20 seconds.
  • VO2 max intervals are for example 6x2 minute intervals, with 1-2 minute recovery. Using distance it may be 6x1km for example. 

    They're hitting a type 3 (anaerobic and aerobic) or type 4 (anaerobic system and neuro-muscular system) response.
  • Short intervals are for example 7x30 on:30 off, with 2-4 minute recovery. This is typically above your VO2max. 

Recovery cost of each interval type

9:52 -

  • Taking a hierarchy approach for the types of intervals (see previous episodes for more details on these), response 5 would be considered the most extreme, and response 1 is the least extreme.

    Sprint interval training is the most damaging, then repeated sprint training, then long intervals (VO2max) and short intervals would be the tamest. 
  • Recovery also relates to the individual. 

    Certain individuals can progress to the higher ones and they become more sustainable, compared to someone just starting out and going straight for the extreme ones. 
  • This is where the art of good coaching comes in - appreciating and understanding the individual nature of recovery. 
  • If you're new to interval training it's best to start with short intervals, and work your way up the hierarchy. 
  • The neuro-muscular response tends to be larger on the sprint intervals (type 5 response) and not always as bad on the central nervous system response.
  • If you repeat short intervals enough and do them at a high enough intensity, you can still get a significant response from them. 

Impact of other factors on recovery

14:00 - 


  • I don't really consider the gender when programming intervals - I don't see too many differences. 
  • I'm aware of the slightly different metabolic responses you may have - e.g. girls tend to be slightly better fat burners than guys, however anaerobic training isn't affected by this much. 


  • Age really comes down to training age - you may not need to programme the training any different for someone in their 50's if they've been training for a long time, but you'd just expect possibly a slightly lower output. 
  • Additionally, some young athletes with a young training age may not be able to do too much high intensity work. 

Working on strengths versus weaknesses

17:19 - 

  • With a triathlete I would start with a performance analysis on an event to establish what we're after and how close they are. 

    Within that I would identify the pinch points - e.g. they're not hitting the 300m buoy quick enough and we need to work on the sprint for this; with cycling, are they getting dropped on the hills?; with running is absolute speed the key factor they're missing?

    From this analysis we shape the intervals accordingly. 
  • Even though we always dream that performance will be a bit better on race day, it rarely is so there shouldn't be any surprises. 
  • Triathlon is an aerobic sport, so even if you are good at anaerobic intervals you probably need more focus on endurance work.

    There's no reason why a short interval sequence repeated enough can't be beneficial, but elite triathletes really need to enjoy the long endurance work. 
  • Sometimes you need to listen to the athlete and give them a bit of what they like! 
  • In my experience I've seen success with both models: 18-hour interval based training weeks, and 30-hour endurance based training weeks. 

Short distance triathlon training example

24:14 - 

  • There's such a range in age-group athletes, from people trying to finish versus people competing at the high end. 
  • Starting with a person who wants to finish the short distance triathlon, and maybe they're time-crunched and training less than 10 hours a week:

    In this case a good set of regular intervals of any kind is going to be beneficial. A 30:30 set may be just as beneficial as 2 minutes on/2 minutes off VO2 type intervals. 
  • Once you transition to a 15-25 hour triathlete and polarised training starts to be more beneficial, then we may focus more on shorter intervals with high power versus longer intervals. 
  • Generally we'd use shorter intervals for shorter distance and longer intervals for longer distance. 
  • I like to have one HIIT workout per week in each discipline to start with. 

    The better the athlete gets and closer to race season, the more we'll add in - both in frequency and variety. 

    You might have a short interval one day, leaving time for recovery and then a long interval session the next day. 
  • I would usually have more interval sessions in swimming, then cycling and the last being running as it has the largest neuro-muscular strain involved. 

    With running, you don't want to do too many too soon, and also you need to ensure you have enough time for recovery. 

Using intervals across the disciplines

28:58 - 


  • I like to have a different focus on the swim each week, but there are 5 key sessions:

    In my elite athletes I like a strength set with paddles and bands (done in a HIIT format).

    Another day they'll be an emphasis on speed (sprint intervals/speed sets). These will be 25's or 50's with longer recovery between them.

    Another day, particularly in triathlon, you need a threshold set with longer intervals (400's).

    Another day will be a technique set. 

    The fifth key session would be in open water if at all possible. 
  • If you're taking sets off, you'll probably take the open water set off first and add the technique session into another day if needed. 


  • Again at an elite level, there are some key days I like to have:

    Firstly a strength, low cadence hill day. These would be more prolonged hill repetitions, ranging from 5-20 minutes. 

    We'd also include a short intervals session, progressing to longer intervals. 

    A good threshold day may be a crit race for a short distance athlete, or it might be a more long- to mid-zone work for an Ironman or 70.3 athlete. For example, 4x20 minutes at race pace. 
  • Cyclists tend to do a lot of mid-zone work too, so it's important to include it the longer you go with races. 
  • There's a good blog that Dan Plews has written about the pyramidial and polarised training profiles.

    Pyramidial is more Ironman/Tour de France athlete. The more you need the high end, e.g. sprint and Olympic athletes, the more you need a polarised plan. 
  • Even in the polarised concept, your threshold will go up. You're still hitting the targets of what will raise an anaerobic threshold. 

    We have done lots of studies that show this is the case. 
  • The key session you'll have with a sprint/Olympic athlete compared to longer distance would be a crit race.

    We always try and get these athletes into this type of race as their heart rate will be in the threshold zone.
  • If your threshold is 200 watts, you could do 1 minute at 220 and 1 minutes at 180 which would be a great set to do for 5 minutes - hovering around your threshold. 


  • In running we have 4 key sessions: tempo, strength & endurance, intervals and long run. 
  • To develop resillience a strength and endurance day is key. For example, easy running over hills. 
  • Key run days are similar to cycling - progressing from short to long intervals. For example starting with 30:30's and progressing to 1km's, and then longer from there for long-distance athletes. 
  • Having a long run will also form a key day, which develops endurance and resilience in the musculo-skeletal system. 

    For short course athletes, the long run is ideally at least up to 90 minutes (but you can start at 30 and progress it). 

    For long course athletes it's not too different, you may aim to go up to 2 hours 20. You don't need to run the full length of the marathon.

    However, long-course athletes may have more frequent run sessions - so still having high volume but split into shorter, more frequent runs. 
  • Recovery runs can also be helpful for some athletes. 

Recovery between HIIT sessions

43:37 - 

  • Recovery is very individual! 
  • Training age is a very significant factor as it will determine a lot of your resilience to your stressor. 

    The more resilient and the less soreness you are experiencing will be a key indicator for recovery. 
  • HRV is a great tool to use as a marker for your centra nervous system fatigue. 

    It can be used in combination with your musculo-skeletal sense of soreness to assess your recovery needs. 
  • Wellness scores and common sense can also feed into this. 
  • They key is consistency and progression. 

    Think 'what is the session I can do today that will create enough stress, but also allow me to complete a workout tomorrow?'
  • It can be helpful to start an interval session, do the warm-up and first set, and then honestly assess how you are feeling. 

    If you start to feel better, you know you can keep going and are ready for the session. This is how you make good gains. 

Prescribing intensity

49:01 - 

  • We see a different philosophy from various different coaches - some prescribe specific power/pace/heart rate. 
  • I personally like to prescribe the target of the session, and call it something the athlete understands. 

    Describe how it should feel - for example for a strength and endurance session you might right 'it should feel heavy'. 
  • You also want to give reference targets which you think the athlete is going to be at for the session - it can be power, pace and heart rate. 

    You may need to adjust these according to prior sessions. 

Paul's new book & associated course

50:44 - 

  • Check out the HIIT science website if you're interested in anything further about high intensity interval training. 
  • Martin Buchheit and I have a long history has researchers, scientists and coaches. 

    Martin works for a high level football club in Europe. 
  • The book is based on a literature review we wrote together in 2013, and human kinetics approached us to write the book on it. 
  • We also created a 12-week course that is certified by the National Strength and Conditioning Association so people can get continuing education credits through attendance. 

    On the course we describe our philosophy and go into the nitty gritty of HIIT.

    We also have world experts embedded in sports around the world describe how they use these principles with their athletes. 
  • With the course you can pick either one sport, or the full sport bundle where you get all 20 sports. 
  • In the triathlon one it is Dan Plews and myself (Plews & Prof). 
  • I would recommend the sport bundle because the swimming, cycling and running sections are so fantastic. 
  • I've personally learnt so much in triathlon from single sport experts.

    For example, looking at the sessions that they use and how these can be incorporated into triathlon training. The mid-zone stuff I learnt from the cycling lecture; also I use the running prescriptions in triathlon programmes a lot as well. 
  • The hard launch date will be the 12th January for the full course. 

    The first enrollment will be up until 31st January, and it will likely be a quarterly basis for enrollment after that. 

Links, resources and contact

Links and resources mentioned

    Connect with Paul Laursen

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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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