Podcast, Science, Training

Sprint Interval Training with Jerome Koral | EP#151

 October 15, 2018

By  Mikael Eriksson

​​​Sprint Interval Training with Jerome Koral | EP#151

Sprint interval training consists of 4-7 all out efforts of typically 30 seconds, followed by 4 minutes recovery. Jerome Koral has researched this kind of training, and the results of his studies indicate that it may be one of the most under utilised types of training around, that more triathletes should tap into.

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:

  • Specific sprint interval training (SIT) protocols.
  • How effective is SIT at improving Time Trial performance, Time-To-Exhaustion, Maximum Aerobic Speed, and so on?
  • How do these results compare to other types of training, like traditional volume-based training or VO2max-type intervals?
  • Injury risk and other risk factors and considerations with SIT.
  • The best times of the season to implement SIT. 

Sponsored by:

Precision Hydration

Precision Hydration
One size doesn't fit all when it comes to hydration. Take PH's free Triathlon Sweat Test to get personalised hydration advice tailored to what you're training for. Use the promo code THATTRIATHLONSHOW to get your first box or tube of electrolyte product for free!


The Stac Zero is the world's quitest bike trainer. No noise and no tire wear, since it doesn't even touch the tire! It is also very portable and affordable. Use the discount code TTS20 for 20% off when you buy your Stac Zero indoor bike trainer.


About Dr Jerome Koral

0:46  -

  • Jerome is a researcher at Saint-Étienne and has done a lot of work on Sprint Interval Training (SIT). 
  • SIT consists of doing 4-7 repetitions of 30 second all out sprints, with 4 minutes recovery.

    In his most recent research this was done back and forth in between cones.
  • The benefits are very positive, in the recent study they found a 6% improvement in a 3000m Time Trial.

    They also found a 40% increase in time-to-exhaustion at 90% of maximum aerobic speed. 

Sprint Interval Training

5:34 -

  • Sprint Interval Training (SIT) is a 30 second all out effort - a supra maximum effort. 
  • The most common protocol is Wingate test on the bike: 30 second sprint intervals, repeated 4-7 times with 4 minutes rest (40-50% of VO2max, pedalling slowly).

    Subjects generally increase the number of repetitions each session, starting with 4.

    For the last session, they will normally do 4 sprints again. 
  • The main topic of our recent article was to validate this type of test in other disciplines such as running. 

Benefits of SIT

7.39 -

  • SIT can help improve VO2max, Time Trials (from 2-10km), time to exhaustion, and mean power output. 
  • These results have been found in both trained and untrained individuals. 
  • When we published our article at the start of this year, there were approximately 25 studies on SIT.

    More than 80-85% of these were on untrained individuals, so the range of improvement was quite high. 
  • We tried this method on trained people. 
  • To our knowledge, the majority of studies have been done on cyclists and/or runners.

Jerome's recent research

9:39 - 

  • In our recent research we wanted to validate the method that allows you to do the Wingate test, but running not cycling. 
  • We used the same protocol: 30 seconds work with 4 minutes rest.

    During the 30 seconds, athletes had to travel the greatest distance possible, and then run back. 

    During the rest, you can walk or jog, but we prefer it to be totally passive. Shortly before the 30 seconds you get yourself 25m from the start and walk to the start. 
  • It was previously used in basketball, known as the "suicide test", which was done to exhaustion. 
  • The main difference here is that it's not done to exhaustion, just for 30 seconds. 
  • Future research will need to focus on whether a shorter or longer rest may provide better results. 
  • We found the same results as the pre-existing literature, but the differences were a little lower as we worked with trained people. 

    However, compared to other methods of training the results were quite high. 
  • Results:

    We measured maximal aerobic speed (similar to vVO2max), which improved by 2.3%.

    The peak power and mean power increased by 2.4%.

    Time Trial performance on 3km showed a 6% improvement.

    Time to exhaustion at 90% of maximal aerobic speed increased by 42%. 
  • This was after only 6 sessions, occurring 3 times a week. 

SIT compared to other training methods

14:25 - 

  • If you compared SIT to traditional methods, the main point is that it is less time consuming than long endurance sessions. 

    This gives you more time for other sessions such as strength training, in the same day as the SIT session. 
  • The outcomes for SIT are better than outcomes for traditional methods. 
  • If you compare to traditional VO2 max sessions such as 5 x 3 minutes on, 3 minutes off, the length of the session is similar.

    Similarly 12 x 1 minute on, 1 minute off would be 24 minutes. 
  • However, with the SIT method, you don't need to measure the distance, you just need 6-7 cones to put one at 5m, one at 10, one at 15m.

    The athlete then goes as fast as they can, they don't need to focus on pacing, just traveling the maximal distance in 30 seconds.

    Therefore, it's an easier method to prepare. 
  • If you can do the workout with a friend you can directly compete in the training, which is an interesting addition. 

Injury risks of SIT

19:55 - 

  • From our study, we had no injuries. 
  • If you respect simple rules, such a progression of training, you shouldn't get injured. 
  • To our knowledge, we didn't see any articles speaking about injuries as a direct result of these methods, however it's quite a new method. 
  • Anecdotally, I have used SIT with rugby players, trail runners, triathletes and football players and nobody has got injured. 

Central or peripheral fatigue 

20:55 - 

  • Central or neuromuscular fatigue has not yet been studied in SIT.
  • We did something similar in Calgary, with a 2-minute Wingate on the bike, but we are still working on the data so I cannot discuss it yet. 
  • We cannot do this with running just yet, it currently remains in the lab. 
  • We have the scientific data which shows that power and mean power are lower at session 2 compared to session 1. 

    On session 3, you return to the same as session 1, and 4,5 & 6 you begin to improve power. 
  • In terms of RPE, all subjects found the methods very difficult, but it became easier as they were more familiar with the process. 

Where is SIT being used


  • Currently I don't think a lot of people are using this method. 

    In my opinion, I feel it's a cultural reason as endurance athletes summarise their training by adding up their mileage. 

    Athletes tend to focus on the quantity, rather than quality of training.
  • I think this is because the coach doesn't want to change the program to try something else, in case the athlete complains if it doesn't work.

When to use SIT in the training season


  • SIT can be used during the taper period, as you'll be decreasing volume but increasing intensity. 

    You can do SIT three times a week with a full day of rest in between. 
  • It can really be used all over the season, but not necessarily in the same way we used in the article. 

    You should use the power output as a way to stop the session. You should take the maximal power output at the start of the session, and then do as many repetitions as possible until you are losing 20% of your maximal power output. 

    Instead of doing 7 at the maximal number for the study, you can go up higher, and then stop once you hit that power cap. 
  • In the article we discuss mean power and peak power which are calculated from the metres you complete during the sessions. 
  • With cyclists, you can use a power meter to identify your power throughout the session. 

Other projects

31:40 - 

  • We weren't sure whether SIT was closer to strength training or intermittent interval training, and therefore which was responsible for the results. 
  • We started testing this. We had 80 soccer players in pre-season and divided them into three groups.

    One group was doing strength training, one group was doing SIT, and the final group (control) was doing normal integrative training.
  • The primary results show that SIT is better than strength training and integrative training. 
  • There's another study we are trying to start on the time needed to recover between sets, and whether this is fitness level dependent.
  • The final project is trying to cross voluntary hyperventilation with SIT.

    We are trying to set up methods trying to mimic SIT at altitude without leaving your home. 

Rapid fire questions


  • What is your favourite book, blog or resource related to endurance sports or your field of expertise?
  • What is a personal habit that has helped you achieve success?
    • I always try to think differently. 
  • Who is somebody in endurance sports or your field of expertise that you look up to?
    • Dave Scott, because of his book Triathlon Training. 30 years ago he knew things that high level athletes now don't know! For example, he knew that lactate was a friend and not an enemy. He was a high level athlete and a scientist. 

Key takeaway

  • The performance improvements from just 6 sessions of SIT are really good:

    6% improvement in a 3000m Time Trial.

    42% improvement in time to exhaustion at 90% maximum aerobic speed. 
  • Dr Jerome hadn't had any injuries in his study and wasn't aware of injuries in other studies either. 

    Since Dr Jerome was using trail runners in his research, they may have been more resilient to this type of training as they have muscular strength from that training.

    Dr Koral recommend that non-trail runners do a bit of strength training before attempting SIT, to build those muscles and help prevent injuries. 

Links, resources and contact

Links and resources mentioned

    Connect with Jerome Koral

    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!


    Let's discuss this episode and the topic in general. Post any comments or questions in the comments below. I'll be here to reply and take an active part in the conversation, so don't be shy! 

    Enter your text here...

    Enter your text here...

    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