The marathon isn’t run at threshold?
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This is for Scott and anyone else who knows more than me about this.
In Scott’s “All About Aerobic Base” he says that the marathon is run at aerobic threshold. I remember him on another podcast amending this a little bit and saying the marathon is run slightly above threshold.
I know a serious marathon runner who in his last race ran a 2:36 and averaged 89% of his max HR for the race. I’ve also talked to a few endurance athletes who say this threshold marathon claim is simply not true. Are they all mistaken?
My thinking is that the marathon has become a short enough event where you can run at a harder effort, and things like ironman/ultras the threshold claim is likely to be true but no longer for marathon….
Great question Theodore.
I think it might be a matter of semantics that is causing the disagreement. At issue is how we define the aerobic threshold.
When I have said the marathon is competed at or a little above one’s aerobic threshold I am basing that on lactate readings taken during training sessions at marathon pace. The elite marathoners that Renato Canova trained in the early 2000s were holding steady at around 2.5mMol/L of blood lactate concentration. While there are some differences between sources most place the aerobic threshold between 2 and 2.5mMol/L
Canova was very open in showing the data on his athletes. One in particular Moses Mosop ran a 2:03 so certainly in the speed realm of today’s top marathoners. I have run across this number in writings by other coaches of top marathoners and at least one study (but I will have to do some searching to find those sources).
It is entirely possible that your friend was able to have lactate levels in that same range at 89% of max HR. Here is why: Over the past 30 years I have personally tested and observed that in very well-endurance-trained athletes the aerobic and anaerobic thresholds separated by as little as 4%. An example is one 4 time Olympian Cross Country skier I coached whose aerobic threshold occurred at about 172bpm and his anaerobic threshold was about 182 and his max heart rate was 188. So, his AeT occurred at over 90% of his max HR and his AnT at over 95% of max HR. From a metabolic standpoint this athlete would be producing about 2.5mMol/L of lactate at his AeT but was able to produce over 18mMol/L during the finishing sprint of 15km race. These are the numbers I personally recorded. From a metabolic standpoint this indicates a huge aerobic capacity coupled with the big anaerobic capacity of a good 800m runner.
I don’t think the marathon has become shorter. It is still 42km and while the elite times have dropped from around 2:10 twenty years ago to 2:05 now, I can’t see how that would dramatically affect blood lactate levels. Lactate is after all a reflection of the glycolytic flux. Every marathoner must husband his/her carb burn rate so as to not run low in the final stages of the race and be forced to slow dramatically. This point you raised about the marathon getting faster so that it is now competed at a higher metabolic state than in the past got me thinking. I looked at the results of the New York City marathon over the past 30 years to see where a 2:30 (the speed of a top amateur male runner) would have placed someone. That time would have placed you 45th in 1990 and 52nd in 2023. In the years in between there is a good deal of scatter in the results but with a barely discernible upward trend. So, I don’t think we can say the marathon has gotten faster for the vast majority of runners. Only a tiny fraction of them are flirting with times faster than the historical winners.
In the end, I think the most important takeaway is that the marathon is an event competed at speed fueled almost entirely by the aerobic metabolic pathway and that training to improve the capacity of that system to produce ATP should be the goal.
Scott
Theodore:
This is such a good question it has really made me pause and think more about that statement I made. Here are a couple more data points. We coach two male ultra runners who also have decently fast marathon times: 2:16 and 2:18. We have done extensive paced training on tracks with both of them to help maintain the speed endurance they bring to ultras. A typical workout of this type (of which have done several) for each of them is to run 3x5km at a pace of 5:10-5:15min/mile (~3:12/km). This would be the pace they would run in order to achieve a 2:15 marathon. Between each 5km they stop for no more than 2min to check blood lactate levels. When they are in good racing form we see lactates of between 2-2.7 depending on the day, temps and wind. These low lactates are what tell us that they are prepared to race well. While this is not the same as stopping someone in the middle of a marathon to test lactate it is a good proxy for running at this intensity. This is similar to what I mentioned in my first reply about Canova controlling the intensity of his marathoners’ training with lactate since this level would be tolerable for the full 42km.
Thanks again for the challenge that made me re-evaluate my thinking.
Scott
Hey Scott,
This is fascinating, thanks for the level of detail. This brings up two questions for me.
1: You say that AeT is 2-2.5. Do you think that 3 sets of 5km actually give a coach a good estimate of where a runner will be for the majority of a 42k race? Seems to me that if someone is pushing 2.7 after 5km (reliably above AeT) you would expect them to be above 3.0 and probably pushing towards 4.0 (stand in for AnT) for a significant portion (>50%) of the race. And those runners are almost certainly spending something like the last 10% of the race well above 4.0.
My second question is a bit off-topic but brought up by the data in this. You’re describing a huge mismatch in HR and lactate. Does this give you pause in leaning so heavily on heart rate in training? If you have athletes that can be at 90% of Max HR and still safely at or below AeT, it seems to me that RPE would be way more reliable than HR or HRR. Maybe this phenomenon is only present in elites? Though in untrained people I think you can see very high heart rates (90%+) that don’t seem to be accompanied by a similarly high lactate level. Thanks for any thoughts.
Danny:
More good questions on this topic. Let’s start with the first one you asked.
I’m doubtful it would be possible for one to maintain a lactate level of 4mMol/L for 50% of a marathon. I’m speculating here because there is a dearth of info on this topic. It might help us if we go back to first principles and examine what is happening metabolically to power the marathon. To run at around 5min/mile speeds takes a lot of glucose or a high glycolytic flux because glycolysis is a faster way of regenerating ATP than is fat metabolism. Remember that the main byproduct of glycolysis is pyruvate which if it hangs around in the cytosol converts to lactate. Both pyruvate and lactate are high-energy fuels if they can be taken into the mitochondria and oxidized. The bigger the aerobic capacity of the muscle fibers the more mitochondrial density and the greater capacity to take up that pyruvate and lactate and do something useful with it. So, while these faster marathoners are producing a lot of lactate it is not accumulating in the cytosol of the cells and blood lactate levels remain fairly low because they have huge aerobic capacity (the big vacuum I refer to in the books). Finding the balance of the fastest speed with the lowest lactate is the goal of any endurance racer in any distance race. That is why we use the types of workouts I mentioned before. It should be obvious that someone who can run 3x5km with a lactate level of around 2.5mMol/L is going to be able to sustain that pace for longer than someone producing 3mMol/L. Not running out of our quite limited glycogen stores before the final miles of a marathon is one of the biggest issues facing any marathoner.
Only someone who paced themselves perfectly would have the glycolytic reserves to run fast enough to produce more than 4mMol/L at the end of a marathon since glycogen stores will be very low. I think this would be especially true for the last 10% of the marathon since we could be talking 15 minutes for a 2:30 runner. Fifteen minutes at say 5-6mMol/L after running 23 miles at 5:15min/mile would seem to me to be superhuman. I once lactate tested some top skiers during a 3-hour Zone 2 workout where I asked them to finish with 5 minutes as hard as they could go. What I saw were lactate levels of 2 and below. The only explanation that I could think of was that their glycogen stores were so depleted that they could not produce higher speeds that would have produced higher lactates.
I sometimes employ a very challenging interval workout for both skiers and runners that will cause lactate levels to reach into the 5-8mMol/L range after the 5th and 10th repetition. To check their ability to sprint at the end of the 10th repetition I will have them do an 800m max effort immediately after we get the lactate reading from #10. When they are not yet in shape I will see low lactates and slow times for this 800 (their glycogen tank was nearly empty). As their fitness improves I see the 800 time drop and the lactate levels climb. This tells me that they can conserve glycogen at faster speeds by using more fat. This enables them to have a strong kick at the finish. A great demonstration of this in action was the finishing kick of Cole Hocker’s gold medal 1500 in the Paris Olympics this week. He had to have conserved his glycogen stores to pull that off.
I’m far from an expert on the marathon or physiology. I am working with what I have personally observed and the little understanding I have of metabolism. If you can find some conflicting information on lactate levels during marathon racing please share them here.
Your second question concerning heart rate: I say forget max HR or % of maxHR as they are not relevant to these discussions. What we do is to find the athlete’s individual aerobic and anaerobic thresholds through very simple testing explained here https://evokeendurance.com/our-latest-thinking-on-aerobic-assessment-for-the-mountain-athlete/
These tests will quite accurately and easily identify the athlete’s metabolic response to changes in intensity. If we correlate this to HR we have a reasonable way to prescribe and control training intensity. If you couple that with RPE you have a nice set of tools for controlling and monitoring intensity that will allow the athlete to learn and correlate HR to RPE under most conditions. One problem with RPE alone is that you have no way of connecting that to the underlying metabolism. So, you are just guessing about that all-important metabolic process that is fueling the work you are doing. The other more insidious problem of using RPE alone, especially for beginners with training is that they have no idea what “easy” feels like and tend to train too hard too often. This leads them into over-training. I have had even high-level ultra runners come to me quite overtrained because they relied on RPE alone. As with the above marathon lactate question it is, again, just my observation of hundreds of athletes over several decades.
I’m not sure I have adequately answered you but thanks for the interesting questions.
ScottThanks for this, Scott. Sorry to eat up your time with an relatively obscure line of questioning. I don’t disagree with anything you said, and think that you described the marathon metabolism picture excellently. This is a little academic and doesn’t really affect a training plan or philosophy.
I’m a rower by trade and my framing of endurance and intensity is naturally going to be different from those who coach and study efforts like the marathon, despite both being solidly categorized as endurance sports. I’m not sure how many marathoners finish with lactate above 15, but I have seen that result rowing quite a few times so I think I was viewing 4mmol as relatively low intensity and not seeing that full metabolic picture. Thanks again.
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