Lactate and bioenergetics: quantifying and improving endurance performance with Shannon Grady | EP#190
Shannon Grady is the founder of GO! Athletics and an expert in the application of bioenergetics, lactate dynamics, and applied physiology for endurance performance optimization. Shannon has worked with over 9000 athletes including Olympic, professional, collegiate, and high school athletes in over 25 sports, and is herself a former professional runner, NCAA All-American, and five-time Team USA Triathlon with 4 Top-10 ITU World Championship finishes.
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In this Episode you'll learn about:
- The science of bioenergetics and lactate dynamics and how they relate to endurance performance and training.
- The fallacy of traditional lactate testing.
- A systems based training approach based on the individuals range of lactate concentration.
- How many endurance athletes lack at least one system and are therefore bioenergetically limited and therefore compromising their endurance performance.
- Training mistakes that lead to bioenergetic deficits and suboptimal performance and training adaptations.
- Nutrition mistakes that lead to bioenergetic deficits and suboptimal performance and training adaptations.
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About Shannon Grady
- She is the founder of Go! Athletics and an expert in bioenergetics and lactate dynamics.
- She has worked with thousands of athletes, from collegiate to Olympic level, in 25 different sports.
- She is a former professional runner and NCAA all American runner, and 5x Team USA Triathlon member with 4 top ten finishes a ITU World Championships.
- I'm a sports physiologist, and a former professional runner and elite triathlete.
- My background is in sports performance. For the last 20 years I've mainly focused on physiological evaluation and training consultation for many high level coaches in the US and around the world.
- It primarily started out in track and field - I was originally a physiologist for USOC so started working with the National teams.
- I then started doing consulting and testing for primarily college and professional athletes.
Now I work with athletes and coaches in over 25 sports.
- I continue to race and compete too, primarily in triathlon.
- The biggest thing is learning the language of the different sports.
Human metabolism and how the body works is the same in all the athletes, but conveying the message can sometimes be a challenge.
You need to understand what's important to them and what they're used too, or you can offend some people!
- For example, swimming is a sport where we're looking at human physiology and optimising energy for optimal performance.
The biggest thing in a lot of swimming models is that swimming athletes train for 5-7 different events that are energetically different.
When you try to broach the subject of optimising performance and focusing on less events, they and their coaches don't like that!
Instead of being mediocre in 7 events, maybe you make the National team in 2 events.
- When you're advising coaches, a lot of them get nervous when they test as they're concerned the testing will show that they're doing something wrong.
You have to carefully explain that testing information is just information, there's no right or wrong training, we're just giving data to make better decisions.
- Human physiology is pretty objective.
Lactate and lactate dynamics
- My interest in lactate began when I started working at the Olympic training centre back in 1998.
I then started focusing on that particular methodology.
- I realised quickly that the information we were disseminating at the time, in terms of how to test for lactate and the use of lactate, is limited.
I found that there is so much more than what the general public, and even the scientific coaching community, was aware of.
- I was curious which fuelled my work - for example when you have a group of athletes on the same plan and some improve, some stagnate, some get worse.
- Understanding this was a personal quest for me as when I went to college I was the number one recruit in the US for running.
I went to a team with similarly talented athletes, some of us improved, some of us stayed the same and some got worse.
I was referred to sports psychology saying I needed to focus and do various other things.
I felt I was doing everything I was told and wanted to do my best but my body was just not responding.
- Lactate happened to be the thing that was easily measurable - in my early career I tested athletes in masses.
I would go to the field and test 60-100 athletes in a day, take samples every 4-6 weeks over an entire collegiate career (4 years).
The tracking and testing frequency was high, and the numbers were high, so the first 3-6 years was gathering and understanding data in athletes that aren't typically included in academic research.
- You've got a lot of research in endurance sports, but my athlete samples were mostly middle distance and anaerobic athletes.
- Essentially, I describe lactate as the human unit of energy.
It's objective and quantifiable, reliable biomarker that has a direct correlation to an athletes ability to perform in a sport or an event.
Testing and using lactate
- The protocol I developed and use as my standard protocol is the physiological profile protocol.
- I originally wanted to test athletes to understand if the training was going well, or not - if they were responding or not.
- The test itself is more of a diagnostic, because when you're observing changes in lactate data, lactate dynamics are influenced by a variety of factors in addition to training.
It can also be affected by nutrition, illness/disease and other metabolic limiters.
- That's a huge part of understanding from test to test what you're looking at - you can't make the assumption that all lactate readings are due to training response or not.
- My model and approach ended up being more of a coaching tool.
In the real world, you're working with athletes and as a coach you know the only thing you can control is the training load.
Athletes are all uncontrolled subjects.
- The diagnostic test is simply a tool for coaches to understand: given this athletes bioenergetic status, what is the appropriate training load this athlete can handle at this time.
- The model I developed is a positive response appropriate load training model.
The profile data gives us the information based on what type of training load, volume intensity and work to rest ratio can this athlete handle at this time to create a positive physiological response, and in turn a positive performance response.
- For example, a runner is going to run you around in the US collegiate system.
They'll probably do cross country, indoor and outdoor track, running pretty much year round.
A college athlete would be tested 4 times a year - at the start of each season (cross country, indoor track, outdoor track and off season).
- The physiological profile test is a lactate test where you start out easily and take a lactate sample on a regular basis.
The intensity and speed gets faster, and you go until a max effort.
You're looking at their entire lactate spectrum and seeing what is their availability of net lactate across the human spectrum.
Their potential net lactate you have for a human is .7 to 32mmol.
- Most athletes are operating anywhere from .7-20mmol.
- When you go to a team you'd have 30-50 athletes that you're testing, an they're all training for the same race.
Ideally their coach is going to give them all the same training, however you may test an athlete and they have half their bioenergetic energy available (half the range they should be operating in).
In a college runner you'd expect .7-12/14 mmol. So if they test and they've got that range, but you test them after the cross county and they have a range of 6mmol, that's half the bioenergetic available from when they had 12mmol available.
- When I test the physiological profile test I break the potential energy of systems into 8 different systems (from low end aerobic to max aerobic) which is dependent on the human range of lactate from .7 - 32.
- What I've found with my testing and research on performance is that performance is dependent on parts of your physiology.
No matter what event you're training for, you'll need parts from all sides of the systems.
If you're training for a middle distance you'll be skewed to the anaerobic side, and if you're training for an Ironman you'll be skewed to the aerobic side.
If you only have two parts of eight available, that's a big problem.
Lactate system parts
- Performance is similar to an assembly line.
If you're trying to build a cars and you have all these parts going into the assembly line and you have 400 steering wheels, but only 200 bodies, your max ability to produce cars will be limited to 200.
In performance it's the same thing. If you're missing parts of your metabolism, whether it's slow energy or fast energy, your performance will be diminished.
- Regarding the 8 parts of the lactate system, for optimal performance you need 6 for any event.
- When you're training and you're missing a part, we can measure to see what needs improvement.
- I've had athletes go into the NCAAs about the race the 800m which you want to run fast!
I had an athlete and we tested him six weeks before this race, and his parts that were missing were the parts that equated to a 5:20 mile pace.
So he's a 1:46 800m and he's going into the NCAAs with super slow training. That was the part that was missing that's going to yield a physiological response as it's holding him back.
- I've found in my performance analysis that every part you're missing under the 6 parts yields a 6-8% decline in performance output, no matter which part you're missing.
- The goal of training and using testing is to diagnose which parts are available and what level they're operating, and then you can identify what type of training you need to improve the overall performance of that system.
It's either train to create more parts - more bioenergetic energy to be available, or train to improve the parts that you do have.
- You can identify what parts you're missing by what levels you can get to.
- If you're training for an Ironman, we're not too concerned with the upper systems, we want to turn those off because you can't have all parts strong at all times.
- As a coach, you look at where they are now, and where they want to be and what parts are optimal or ideal for energy output for the event the athlete is training for.
- Low end peak energy for Ironman is the low end of the spectrum, but you don't want to go in with just two parts available.
That will diminish the overall ability of your low end aerobic system to operate efficiently, and at a higher rate of output.
You still need a physiological range.
Theoretical underpinnings for lactate system parts
- A lot of this is based on the theory of thermodynamics.
- My main theory, the Grady Human Efficiency Theory, is based on the fact human performance has two main rate limiters.
This is similar to Carnot's Efficiency Theorum - in terms of energy, efficiency and the ratio of output energy and input energy.
Essentially, Carnot's theory and my theory of human performance is the difference between the input and output, or the max and the min.
If your difference is smaller, your possible efficiency is going to be decreased, and how well you convert energy is going to be decreased.
- I've seen across every example where the acute physiological range is diminished, the performance output drops. For every system you lose, the output is decreased by 6-8%.
- This gets into energy and metabolism - if you have two systems and you only have the two low end aerobic systems available, you're limiting your substrate ability (metabolic adaptability).
- If you have an 8 cylinder engine, and you're running off 2 cylinders, you're going to have trouble operating it.
The difference between humans and machines is we don't have as many ways to measure this in humans.
This is what I'm trying to work on - using lactate along with velocity and power data I've developed different metrics which will essentially indicate if that person has different performance capabilities.
If that energy they have available is operating at a level high enough to perform certain tasks.
- I started out in running, which is great because it's a measured variable sport. You can measure the velocity, the distance etc.
You need certain scores across each system to run a 4 minute mile compared to a 5 minute mile.
The velocity at each net lactate needs to be at a certain level across your energy spectrum in order to achieve certain performance results.
- When I got to a coach and present the results, and they wonder why I suggest an athlete does slow training right now, I can show them the data that says which part of their energy is too low.
If you target the area that is missing, the overall output will improve.
- If you're talking about the mile, you have 8 potential systems, and if you hit the mark in 5-6 of them then you're most likely going to do it.
If the person isn't there at 2mmol, which is often the case in middle distance athletes, but they're relying on the anaerobic system, you're going to need to hit the mark in 6 of the systems.
Using lactate testing to support training
- The test itself is generally 800m repeats depending on how fast you are.
If you run 10 minute mile pace or faster, then you're going to run 800m repeats, any slower and you run 400m repeats.
- You start at a slow speed, and this varies based on the athletes current fitness level.
You then increase velocity over the 800m, taking heart rate and lactate measures between each one - resting for about 10 seconds.
- You go on until you can't go any faster in the 800m.
- The test is diagnostic, you're looking at of these 8 parts, how many do you have available.
- For an elite athlete, we want 6 parts, for a recreational athlete we want 5 parts.
- Depending on the event, you'll skew the parts left or right (aerobically or anaerobically).
- I've built a predictive response model that will achieve the intended lactate response based on the training stimulus that is given.
If you have 3 parts available, you're going to get the training prescription that's goal is to get you to 5 parts.
We'll give a training load and intensity that is appropriate for you, heart rate zones and work:rest ration that's going to create more parts.
- In 90% of first time physiological profile analysis, most people have a bioenergetic deficit (less than 5 parts).
- If you have this deficit you're going to go into NAGS training - neuromuscular adaption glycogen sparing training.
This is limited in volume and intensity. The goal is to create more energy so put you in a glycogen sparing phase for a certain amount of time.
Typical NAGS training in an elite athlete will gain a system is 7-10 days.
- What people typically think of as a taper, you will gain a system, which automatically increases your performance by 6-8% - it's free speed.
But in actuality, if you're training with missing parts you're not actually training the energy you have available.
So essentially you're relying on a taper to gain energy and then perform at a level that you haven't trained.
- The super-compensation, which is a common model in several sports (swimming and rowing in particular) where they rely on the taper too much, isn't ideal for training.
You'll perform better if you have that energy available and you're training it, so you then gain even more in the taper.
- If you have a race car, which is a high performance vehicle similar to the anaerobic system, it runs off high octane fuel to make it run the way it does.
Then you have some other type of car that runs on low efficiency, it's designed to go longer and use more of an efficient fuel and won't go as fast.
But in humans it's different, because you have the two ends of the spectrum and everything in the middle.
If that high octane car runs out of fuel, it's going to stop. In humans, we won't stop, our bodies adapt.
We adapt to the fuel we have available, so even if you're intending to be a high octane athlete you can only adapt to what you have available.
If you've burned out your high intensity fuel, you're going to adapt to the next inferior source. In turn, your ability to generate velocity and power is decreased so we get slower.
- Athletes work hard and train hard and burn out their high energy, so they adapt to low energy and their performances increasingly decline.
They think they're working harder and harder but in reality they have no good fuel left and they're just adapting to the slower fuel until they eventually get injured.
- You can see what your risk of injury is based on the number of systems you have available.
When you're constantly asking your body to do something outside of its physiological range, your risk of injury is greater because you're asking it to do something it's not prepared to do.
- Athletes are often left to go on how they feel after injuries or illness, and there's no guidelines to tell them what's safe and appropriate.
The return to play test will help tell them that.
Example training with Ironman age group athlete
- The training plan prescribed will be based on how many systems are available - how much NAGS training do we need to perform?
In novice athletes it's going to take 10-14 days to gain a system, so if they're only missing one we'll drop volume and intensity for 10-14 days.
- If they're only missing one I don't need to know calories, carbohydrate intake etc, because I found a direct correlation between low carb diet and bioenergetic availability.
When athletes aren't consuming enough carbohydrate it has a direct impact on their ability to perform.
- If an athlete shows up with 3 or less systems, I'll do the food log evaluation.
Training is energy out, and fuel and rest is energy in. The test will show you if bioenergetics are in balance.
If there's less than 5 in an age group athlete, we're imbalanced somewhere - either you're outputting too much or not inputting enough.
- If you have a mild bioenergetic deficit (4-5 systems), we'll give 2-4 weeks NAGS training.
- If you have 2-3 systems available, we'll cut back training for a minimum of 4 weeks and do a food log to check your macronutrients are in line.
- I've found anybody who is consuming less than 55-60% carbohydrates is at risk for bioenergetic deficit if they are an athlete.
- The general recommendation is getting them to 55-60% carbohydrates as the first step as without that they'll continuously be in an bioenergetic deficit and underperforming.
- NAGS training will limit total work to 75 minutes a day, and go into mid-low aerobic heart rate zone.
You won't do any interval training above your available energy systems.
- For example, when I do the test results it's going to give you training paces for each of the systems and that correlates to that NET energy output.
You won't get given a velocity greater than what is available.
The speed that you may do some intervals will be what is appropriate to your test results.
You may be capable of running faster, but from a physiological perspective you don't have the energy capability to do so, so you won't be doing it in training.
- We're priming energy systems to become available or ready for subsequent stages of training.
Energy priming serves two purposes - NAGS training is one where you're trying to generate systems.
This is essentially less than 20 minutes of total work, with intervals anywhere from 20-60 seconds with 1:1 work:rest ratio at the appropriate velocity.
The purpose is to gain energy.
- The training prescription is on the coach, the fuelling is on the athlete.
- From there, you look at when the race is and what is your goal energy system for the event.
For an Ironman we're going to be at the low end of that energy spectrum, in the long aerobic energy (prolonged aerobic capacity system).
This is something in the 2-4mmol range.
- Then you look at between now and peak, how much time to I have and how many systems can I develop between now and then.
- In general I prescribe to a single stimulus block approach.
I found that in researching and tracking it creates the most predictable and accelerated response rate - you can predict the physiological response and the lactate response.
I'll put them in there for 4-6 weeks for each system. After that amount of time, the biochemical stimulus, the training of that system, essentially drops off.
- Going back my approach that different laws of thermodynamics also apply to human bioenergetics, I've found that randomised training yields randomised responses and unpredictable performance results.
Similar to the second law of thermodynamics which affirms that the higher randomness of a system the higher its entropy.
Generally in a training block you'll have recovery days, aerobic maintenance days, and a main system workout that is the focus of that training block.
Ordering training for systems
- The order will depend on the result of the test and how much time you have.
It's not going to be least to most trained system.
- For an Ironman you're going to end with the prolonged aerobic capacity, which is generally an available system unless you're completely under-fuelled and in a massive bioenergetic deficit.
- Leading into that, most often people have to start with NAGS.
- In the middle, I would put in one of the VO2 systems, somewhere in the 6-12mmol range depending on the result and the person, and how many systems we can train in between testing and the peak event.
- I would never do adjacent systems because the biomechanical stimulus is too similar so you won't get as strong of a response.
Generally you'll have one or two systems between stimulus from phase to phase.
This is not commonly done, which is why when I test most people they're in a bioenergetic deficit.
- When you're working adjacent systems you're going to set yourself up for performance stagnation and decline, and decreasing bioenergetic availability.
When you train, the goal is to improve, so what was one system might not be another.
Focusing on one substrate for a prolonged period of time results in your physiological range shrinking - you're pulling too much energy into one spot so it will shift and you'll get diminished metabolic adaptability.
Common training mistakes
- The most common one is not planning rest! Endurance athletes in particular are afraid to take time off.
- I worked with Villanova University and see their athletes a couple of days a week.
One girl had a tweak in her back and had a big 5k coming up. I had to put her at ease and explain that you can take up to 14 days off and you're gaining fitness, not lose it.
You just need to do a couple of intervals (100-200m) at race pace, and then take off time.
She was afraid, but she ran a 20second PR 5k and was really happy.
- I found that most people don't take time off unless they're injured, and then they have to take it off.
As humans, we adapt to inferior fuel until we absolutely have to stop because we're hurt, from continuously working outside of our actual limits.
- I always put a transition week in between phases, a zero stimulus week.
There are also regular days off.
- Sprinters don't have a hard time taking off, but endurance sports athletes get more nervous doing this.
- I think a complete day off is hands down preferable to an easy day.
- The assumed energy approach because most people don't have access to actual energy.
The general concept and understanding of the lactate threshold is that 4mmol is the lactate threshold.
The reason why I don't use 'lactate threshold' or a 4mmol mark to set training is because in human physiological profiling, physiology is dynamic.
At any point in time, a net lactate value of 4 can be anywhere from 16-100% of one persons maximum lactate value.
- I started out with middle distance athletes and I realised that 4mmol can be somebody's max value, which is bad!
Two people being prescribed the same training based on this classic value can lead to one over-training and one under-training.
- There are lactate thresholds at each net lactate level and they're all trainable.
Basing it one training point (the 4mmol lactate threshold) will be doing a disservice to most athletes.
- Going back to lactate as a unit of energy, each unit of energy is unique and has different components and characteristics.
Some are meant to operate long slow, and some are meant to operate fast and short, and then there's everything in between.
The assumption of most is that everyones capacity to do work is the same at each unit of energy, but this is not true.
- My approach is to work within known variables - what we can measure is somebody's power or velocity at each unit of energy, and we can train capacity.
But we don't really know their capacity to do work - we don't have the technology available to measure that.
- The confines that I give to my coaches are velocity or power, and we train capacity.
- Say if your velocity at a certain energy, net lactate value, is such, we train the amount of work you can do at that power/velocity and try to increase capacity, instead of assuming capacity to do work.
- I know many athletes who can't do an hour work at any intensity, so it's a poor assumption that you can do an hour at threshold.
- I've found a direct correlation between low carbohydrate diets and bioenergetic deficit.
- People need to understand that lactate is a very miraculous molecule. It's not a waste product, it's a major energy source.
- However it's also needed for glycolysis, and it's a signalling molecule for hormone production.
- When you're in bioenergetic deficit, when you eat low carb diets your ability to produce lactate is diminished, which will lead to an inability to maintain homeostasis.
- This is the biggest problem with the high fat low carb diet. The notion of becoming fat adapted is ridiculous because there isn't an infinite ability to adapt to a substrate.
If you're limiting your substrates to fat, you are limiting your ability for glycolysis, your ability to produce lactate and to produce hormones, all of which are key for performance.
- You're not teaching your body to burn more fat, you're essentially slowing down your metabolism.
It has the opposite effect of what you think you're doing. Your ability to burn fat will be drastically reduced because if you only have fat available your body will store it and slow down, because it doesn't have the fuel and metabolic adaptability it needs from other substrates.
I have hundreds of case studies of this.
- When I test somebody and they have 1-2 systems available, I automatically do a macronutrient and micronutrient evaluation and pretty much 100% of the time it's a low carb, high fat diet.
- Not only are they experiencing a progressive decline in performance, but they'll also be experiencing an inability to maintain homeostasis in general health.
You will have hormone production issues, low T, cortisol, everything is thrown off because lactate is a key part of many things in the body.
Your ability to produce lactate across the spectrum is very important, and in order to do that you need adequate carbohydrates.
- The basic science shows that the human body has feedback systems for survival purposes.
If our good fuel (carbohydrates) is short, we go to survival mode and we adapt for survival purposes.
If we adapt to fats, it's called ketosis, and this is going to inhibit glycolysis and this is the big problem.
When you inhibit glycolysis, you can't produce adequate amounts of lactate that will help with maintaining homeostasis and hormone production, but also limiting your ability to produce ATP.
- Everybody thinks they can trick the system, but the rules of human metabolism still apply to everyone.
The bioenergetic costs of relying on fats compared to carbs is that the velocity or power of work rates will be diminished.
- There's no science where this approach has worked, and it's just bad for your health.
- With train low, race high, it again doesn't really work.
You need the higher end systems to be able to effectively convert oxygen into energy, even if you're an Ironman athlete.
Rapid fire questions
- What is your favourite book, blog or resource related to triathlon or endurance sports?
- The work of Alois Mader, and George Brooks.
- What is a personal habit that has helped you achieve success?
- My ability to enjoy rest and recovery, and my focus. I try to incorporate dynamic stretching before every workout, something so simple can really improve and increase the life of your sport.
- What do you wish you had known or done differently at some point in your athletic career?
- I wish I would have learnt to swim as a kid, and started doing triathlon earlier.
- I got injured a bit in college and then started training with a triathlon club but didn't start properly until a while after college.
Links, resources and contact
Links and resources mentioned
Connect with Shannon Grady
Go! Athletics - Shannon's website
On Twitter - @goathleticsceo
On Instagram - @goathleticsceo
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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A simple question: aren’t those 8 “energy systems” just a more sophisticated version of “training zones”, in this case, established by ramp lactate measurements either than percentages of HR or Output references?
Yes and no. A heart rate range or power range or pace range really tell you nothing about the bioenergetic availability you have. And in the classic ramp test protocol people only care about the actual thresholds rather than the bioenergetic availability, which Shannon specifically stated is not ideal for various reasons.
In Shannon’s methodology, there are no thresholds (and admittedly thresholds are a bit ambiguous) – the bioenergetic availability is what determines what to train and why.
In a classic ramp test we get two thresholds, and maybe some suggestions about training to improve one of them as that might be a relative weakness. But HOW to train that and WHY choosing that methodology is completely missing. Should we pull LT2 from above, or push it from below, for example?
Shannon’s methodology gives a clear idea of what intensity range we are lacking in or missing completely and is therefore much more unambiguous.
That’s my take from this interview anyway, although I haven’t actually tried this sort of testing (yet).
Unfortunately it’s not entirely clear what Shannon’s methodology actually is based on this interview or how it differs from a standard ramp test.
There is a lot of mention of models and metrics but no mention of the underlying science backing them.
There is also an unusual use of the word “energy” throughout the interview – “slow energy”, “fast energy”, “most people don’t have access to actual energy”. I’m not sure what Shannon means by “energy” but I don’t think it’s the same definition as the rest of the sports-science community.
I don’t think there is anything new here – but it is extremely opaque and being phrased in a way to make it sound innovative. Perhaps it was a difficult medium for Shannon to express her concepts.
But the fact that Shannon has given her Energy Zones names and trade-marked them probably tells it’s own story.
It wasn’t clear how “missing” systems are determined from the test. After the test is done you get a standard lactate vs speed/power profile. How are these missing “energy systems” determined from this profile?
Lactate is only part of the metabolic picture. You also need to get
better picture of how your body is utilizing fat and carbohydrates at
certain intensities (speed/power) and you can only get that by looking at VO2/VCO2 data.
Like Ivan, I was also a little confused how exactly this corresponds to VO2Max and VLaMax as discussed in the episode with Sebastian Weber. I loved the discussion of tapering and think that could be its own article/blog post. I have been really confused why my coach’s relatively short taper has worked well for me and I think this is why!
Here’s an archived blog post by Shannon that illustrates
a few examples:
Unfortunately, there’s still no explanation of how these “scores” are obtained.