Advanced, Podcast, Running, Science

Running science: economy, strength training, lactate threshold, and performance predictors with Jordan Santos | EP#117

 April 9, 2018

By  Mikael Eriksson

Running science: economy, strength training, lactate threshold, and performance predictors with Jordan Santos | EP#117

Jordan Santos, associate professor, discusses a number of topics within running science and their practical implications for triathletes. 

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:

  • Lactate testing best practices, validity of field testing to estimate lactate threshold, and using heart rate variability to estimate lactate threshold in the near future? 
  • Running economy: how important is it and how can it be improved? 
  • Strength training for running and its impact on performance. 
  • The best predictors of running performance. 

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About Jordan Santos  

0:35 - 

  • Jordan is an associate professor at the University of Basque Country in Spain
  • Jordan has conducted and supervised research in the variety of areas covered in today's podcast.
  • In addition to his knowledge about the science of running, Jordan is a very good athlete himself.
  • He has worked with Professor Tim Noakes and Dr Ross Tucker - two of the most famous sports scientists in the world.
    • This was when he worked as a post-doctoral research fellow at the University of Cape Town.

Estimating the lactate threshold in distance runners 

4:44 -

  • Lactate threshold is one of the main physiological determinants of performance, together with running economy and VO2max.
  • I try to understand which lactate threshold method is the best one to adequately measure running performance in runners of different levels.
  • We have many strategies to measure lactate threshold these days, and every one has a different meaning.
    • Even if it's a small difference between methods, we may not calculate the exact data point that we want for our training plans.
  • I am conducting research to see which equation is the best for lactate threshold determination, the ideal length of the workload and ideal recovery etc.
  • The main problem with the incremental maximal test to determine ventilatory thresholds is that, in my opinion, the results are highly unreliable.
    • We need a gas analyser to determine them, and many runners feel a lot of discomfort during these tests.
    • Sometimes the results you get doing this on a treadmill are not great.
  • I prefer the classic lactate tests on a track.
  • The gold standard is the maximal lactate steady state method.
    • However you need 3-4 training sessions to determine this factor.
  • I am trying to work on the best strategy to determine lactate threshold using only one training session.
  • For what I've seen, the best method is the Dmax Strategy.
    • This is not the easiest to calculate but it's the most reliable.
    • During the session you have to do at least 6 workloads.
      • The initial workload lasts around 3 minutes, or you can use 3 laps (~1200m) on a track.
      • The initial intensity is around 50% of VO2max.
      • You have 20 seconds of recovery between each workload, and you incrementally increase the pace by 10%.
      • I.e. the second workload will be 60% of VO2max, the next will be 70% etc.
      • You complete 6 workloads with this incremental increase and you end up with good data points.
    • Using the data points, you can calculate the lactate threshold using different techniques.
      • I prefer the Dmax method.
  • The Dmax method is already published.
  • Once you get your 6 data points, you can perform a regression equation.
    • You can use two different regressions:
      • Polynomial regression is the most typical and easiest to understand
      • Exponential regression is more reliable because it doesn't get affect as much by the initial intensity, but it is complex to calculate and it's not easy to understand.
Lactate threshold in running and triathlon - Dmax equation

Dmax polynomial regression model - Source

  • You have to go to Excel and insert the data points. From here you can use Excel to calculate a regression line and you can select polynomial regression.
    • This gives you a lactate curve, and you then have to calculate the lactate threshold.
    • If you use the D-Max method you draw a straight line from the first point to the last one, and see what the maximal distance between that line and the curve you calculated.
    • The maximal difference will be the lactate threshold.
  • I compared this test to the onset of lactate accumulation test, which corresponds to 4mmol of lactate.
    • Many athletes still use the 4mmol of lactate as an indicator.
    • However, we have seen that this is not the same for every athlete, so I wouldn't recommend the use of this test to estimate training intensities.
  • Conducting field tests (e.g. estimating lactate threshold pace based on a 20-minute test) is not the most reliable strategy, but a lot of people don't have access to a lactate analyser.
    • For people with no resources this can be a good enough strategy.
  • We have compared the results you get from a field test to what you get using lactate testing equipment and found the differences differ depending on athletes.
    • For some athletes, the 20-minute test underestimates the lactate threshold, but for others it overestimates it.
    • The error can be around 5%.
  • If we are training elite level athletes we have to individualise the training plans perfectly, and a 5% difference to the real lactate threshold may imply that the athlete is training too hard and the risk of over-training is there.
    • For elite athletes I always recommend proper lactate testing equipment.

Periodisation and training intensity distribution

13:05 - 

  • I worked on this topic as part of a project for a PhD student of mine called Mark Kennealy who was an Olympic marathon runner in 2012.
  • He wanted to focus on training intensity distribution and is trying to see whether different periodisations are better for runners or not.
  • At the moment, most runners use either the pyramidal or the polarised training intensity distributions.
  • But we've seen that most of the best athletes in the world use the threshold periodisation.
  • We are trying to basically unravel what's going on here - trying to see why the best athletes in the world (i.e. Kenyan's) are using threshold periodisation.
    • According to the scientific literature this periodisation is not the best.
    • We're trying to see why it works for them when studies say it's not the best method.
  • Hopefully, in a few months we will have an answer!
  • So far we've done a literature review published in the International Journal of Sports Physiology and Performance.
  • At the moment, we are working with a team of elite endurance runners from Australia.
    • We are also working closely with an Australian coach called Nic Bideau who works with the best middle and lost distance runners in Australia.
    • We have tons of data but we haven't analysed it yet!
  • In terms of the models, when we talk about periodisation we're discussing how we distribute the different training intensities.
  • The difference between the three main models is how much time is spent at each intensity:
    • The polarised model involves spending a lot of volume at low intensities (far below lactate threshold), and a lot of volume at zone 3 (higher than lactate threshold). Less volume will be spent at zone 2 (lactate threshold).
    • The threshold model involves training a lot in zone 1 and zone 2, but less in zone 3.
    • The pyramidal model involves spending a lot of training volume in zone 1, a little bit less in zone 2, and a little bit less still in zone 3.
  • For listeners who are used to 5-zone systems (or other versions), in scientific literature, training zones are typically often simplified and only three zones are used.
    • The first threshold (aerobic) is the border of zone 1 and 2, and the second threshold (lactate, anaerobic) is the border of zones 2 and 3.

Improving running economy

16:50 - 

  • Running economy is one of the main determinants of endurance performance.
  • It has received a lot of attention in the last decade, and we've seen you can predict whether a runner is good or not based only on running economy.
  • Running economy is the amount of oxygen or energy needed to cover a set distance.
    • Usually it's 1km.
  • We have seen that elite Kenyan and other African athletes are more economical and efficient than European athletes of similar profiles.
  • With running economy there is a huge margin of improvement.
    • Similar to other physiological determinants of performance, running economy can be improved with training.
  • There are many ways to improve running economy, such as:
    • Improving your biomechanical technique.
      • If you have a bad technique (e.g. over-stride, or heel striking), by changing it you can improve your running economy, become more efficient and perform better.
    • Including proper strength training into plans.
      • This may dramatically improve running economy.
      • You can improve performance without affecting your VO2max or running threshold.
      • The improvements, according to the literature, can be close to 10%, particularly for recreational runners.
      • Strength training makes you stronger and able to tolerate higher training volumes.
      • It also helps reduce your risk of injury, increase efficiency and help you run faster.
  • Running is not just going out to the park and doing a long run.
    • To be an elite runner you need to go to the gym and lift heavy.
  • We've seen that the best strength training is doing heavy lifts, at the maximum speed you can move.
  • I encourage every runner to try to level up their strength training and include 2 sessions a week to see real improvements.
  • With strength training you need to work at low reps (4-5 reps) and that will be around 80% of 1-rep max.
  • Go for the basic exercises such as bench press, squats, hip thrusts, dead lifts, lunges etc.
  • Plyometrics, such as drop jumps or multi-jumps, can increase the stiffness of tendons.
    • This will also improve running economy and efficiency.
    • You improve the body's ability to release elastic energy out of the tendons so you can run the same speed but expend less energy.
  • Plyometrics are great but they're not for everybody.
    • For an elite or middle distance runner they're fine.
    • For recreational runners, if you don't have a good technique or somebody supervising the exercises, you might be at risk of an injury.
  • Progression is recommended, starting with steady lifts at the beginning of the season and moving into more explosive strength training.
    • E.g. including Olympic weightlifting such as cleans, and then including plyometrics closer to race season.
  • The complication for triathletes is that the same applies in terms of heavy weights/low reps, but the explosive components isn't as helpful for cycling.
  • For a runner, it's great to have a huge stiffness, but this might impair your performance in swimming.
  • In triathlon, in order to be really successful the most important part is probably the running.
    • Cycling, with drafting (in elite, draft-legal racing) is not as important.
    • A good runner will be a more successful triathlete than a good cyclist who can run.
  • It's important to find a balance.
  • Strength training should be included twice a week minimum if you're aiming to improve your performance.
  • Other factors that influence running economy are:
    • Gender - men are more efficient than women.
    • Age - we are less efficient as we get older.
    • Ethnicity - we've seen that African runners are more efficient.
    • Anthropometrical factors - if we have a lot of weight in the distal parts of the body (e.g. calf area) this will impair running economy.
  • The only factors that we can change are biomechanics and strength training.
  • Running technique exercises are key for a basic training plan.
    • These can be included in the warm up at the beginning of the season.
  • According to certain new research, we know that a forefoot strike pattern is more appropriate for running economy.
    • But a lot of runners are heel strikers.
      • Barefoot running has been proposed as a strategy to change from heel strikers to forefoot running.
      • Some people are able to do an 8-week barefoot training plan to switch, but it doesn't work for everyone.
  • We should aim for long strides and lower stride frequency.
  • The first rule of biomechanical change is that every conscious change will negatively affect your running economy.
    • The way you run is the most economical way you can run.
    • The body adapts to that specific form.
  • However, we've seen that the best athletes in the world have slightly longer strides and a slightly lower stride frequency.
  • If we can unconsciously change our stride length and frequency, for example by getting stronger in the gym, doing strength training or being more flexible, we'll improve performance.
    • The changes have to be progressive and a consequence of training, not a conscious change.

Predictors of running performance

28:50 - 

  • When we try to predict performance we have to look for different factors.
  • In endurance performance the typical factors are the physiological ones.
    • The three main pillars of endurance performance are:
      • VO2max - this is a good differentiator between bad and good runners, but it can't identify differences between a collection of good runners.
        • A minimum VO2max is necessary to be an elite runner, but after that it wont make much difference.
        • Most of the best African runners in the world have modest VO2max figures of 64-65, which isn't amazing.
        • I myself have a VO2max of 81 and I am definitely not an elite runner that could go to the Olympics!
      • Running economy.
      • Lactate threshold.
  • There are other physiological parameters such as brain oxygenation, which looks at how much brain oxygen drops when we are close to exhaustion.
    • We have seen that African runners are able to keep the brain oxygenation stable even at maximal intensities.
    • In Europeans, high intensity exercise leads to brain oxygenation going down.
      • When brain oxygenation goes down by a certain amount we simply stop exercising, so we know it affects performance.
  • This happens because when we are exercising at intensities higher than the respiratory compensation point, we are breathing a lot and giving out a lot of CO2.
    • As a result, the partial pressure of CO2 in our blood goes down and this leads to vasoconstriction.
    • The vasoconstriction reduces the blood flow to the brain so the brain oxygenation goes down.
    • This affects the cortical activation of the neurons in the frontal cortex.
    • This area is related to decision making.
  • This doesn't happen in African runners.
    • One hypothesis about why this might be is due to early life factors such as exposure to high altitude and high amounts of exercise activities during childhood.
    • As a result of this, they develop certain characteristics including greater vascularisation of the brain.
    • This may explain why they don't suffer from brain oxygenation decrements at maximal intensities.
  • Going back to predictors of performance, in swimming and some other sports the biomechanics is a key factor.
    • With a bad technique you cannot be an elite swimmer.
  • Similarly in cycling, a good aerodynamic position is important but not determinant.
    • To be a great cyclist you need certain physiological characteristics.
  • One of the main determinants of performance, especially at the elite level, is to have a very strong mind.
    • According to Samuele Marcora's theory, the main determinant of performance is the perception of effort. The mind plays a big role.

Measuring lactate threshold using heart rate parameters only

33:14 - 

  • We've seen that the lactate threshold is related to certain heart rate parameters like heart rate variability.
  • We are trying to develop a heart rate monitor that can estimate your lactate threshold just by measuring your heart rate variability.
  • We are doing artificial intelligence models with an engineering company at the moment.
    • Hopefully in less than 1 year we will have a new heart rate monitor that can estimate lactate threshold without taking blood samples.
  • In the future this will be a great thing!

Rapid fire questions

34:10 - 

Key takeaways

  • Strength training is really important, and can give up to 10% improvement in running economy.
    • This needs to involve heavy weights, low reps and high speed strength training.
  • We can improve other aspects of running economy.
    • For example, using barefoot running to achieve a forefoot strike.
    • Conscious changes to running form usually impair running economy.
    • Changes need to be unconscious consequences to changes to flexibility etc.
  • It's important to know what the validity of a 20 minute field test is for lactate threshold and Jordan said for amateur athletes this type of test is okay!
    • The error is in the region of 5% which isn't terrible.
  • Also Jordan reiterated what previous guests have said about how important the mind is in endurance sports.
    • Make sure you listen to the related listening episodes for more on this topic.

Links, resources & contact

Links and resources mentioned

Connect with Jordan Santos

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. 

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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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