Hey Bruno,
Great questions. I’ll do my best to clarify.
The shortest summary can be done with two questions:
How much aerobic capacity do I need?
As much as possible.
How much anaerobic capacity do I need?
It depends on the event.
It’s really important to understand that the position of a lactate curve reflects the relative strengths, and not the absolute strengths, of aerobic capacity (AeC) and anaerobic capacity (AnC).
If two athletes have a similar heart rate range and the same relative balance between AeC and AnC, they could have identical lactate curves even though their speeds may differ. Lactate curves primarily describe fuel usage relative to intensity.
They don’t predict speed, although plotting lactate against speed is the most useful way to use lactate. Speed is obviously more performance-centric than heart rate.
You said:
So I set the Anaerobic capacity at a middle/average value, 3, and I set the Aerobic capacity at the lowest level, 1. Then I increased the Aerobic capacity, level by level. As I expected, the lactate curve stayed roughly the same shape (until the highest level) but shifted to the right, indicating that the swimmer could achieve a faster pace, and produce the same lactate values. If I understand correctly, this is similar to doing lots of low-intensity running or hiking, raising your Aerobic capacity, after which your pace for a specific effort will increase. So far so good.
Correct.
Then I did the opposite. I set the Aerobic capacity at a middle/average value, 3, and I set the Anaerobic capacity at the lowest level, 1. Then I increased the Anaerobic capacity, level by level. In this case, the lactate curve shifted to the left, indicating that the swimmer went slower as his/her Anaerobic capacity increased.
Instead of thinking of the athlete as going slower, think about when the athlete’s metabolism starts to favor anaerobic energy production over aerobic. An athlete whose AnC is too strong relative to AeC will start to switch over earlier than an athlete with a relatively stronger AeC.
In short events, there could be no difference between the speeds of the two athletes. But in events lasting two hours or longer, it becomes a fuel issue. The athlete with the too-strong AnC will run out of glycogen before the athlete with a relatively stronger AeC.
Sadly, in cases where an athlete has solely focused on high-intensity training, they can destroy their aerobic capacity. For those athletes, they start to switch over to anaerobic metabolism at very low levels of intensity. In extreme cases, athletes that have destroyed their AeC like this are somewhat anaerobic (i.e. above ~2 mM of lactate) at any level of activity.
The reason for this is that chronically elevated levels of acidosis (not because of lactate, but in conjunction with it) destroy mitochondria. Mitochondria are the “aerobic engines” of muscle cells, so killing them off is a bad idea. Constant high-intensity training repeatedly creates elevated levels of acidosis.
All world-class athletes use high-intensity work in their program, but in much smaller proportions than what has become popular in recreationalists. As an example, although Kenyan runners are often described as using a lot of high-intensity intervals (and it’s true), that high-intensity work accounts for only 10-15% of their training. (* Based on Renato Canova’s training programs.)
Is the explanation that when an athlete has a high Anaerobic capacity (fuel store like ATP and creatine phosphate, enzymes, cellular machinery, metabolic byproduct clearing mechanisms, and so forth) these systems simply kick into gear at lower intensities, thus raising blood lactate, and limiting pace?
Correct.
Again, how would lowering an athlete’s Anaerobic capacity make them faster at a particular distance?
The important thing to remember is that a lactate curve’s position is a result of the relative strength of AeC and AnC.
Think of the tug-o-war in the animation. If one side gets weaker, then the opposing side will gain ground.
Three examples:
ONE
I have a friend who was very fit and very powerful. He had a very big engine, but was overdoing high-intensity. His curve was further left than it should have been, and his AeC had actually dropped. Then he developed chronic lower back issues. He had to take a lot of time off, and when he became active again, he could only do low intensity.
I tested that friend before and after his back issues. The change in curves? Metabolically, his lactate curve improved. He was certainly slower, yes. But measured by heart rate, his curve had noticeably shifted to the right. We’re now in the process of speeding him back up, which is going well.
This friend’s curve had shifted to the right, because both AeC and AnC had weakened, but AnC had weakened more. The relative strengths had changed.
TWO
I tested another friend twice during his training. His second curve was noticeably shifted to the right. (His ~4 mM HR moved from ~165 to ~175.) At first I thought that this was due to all the training he had been doing, and some of the shift probably was.
However, I then found out that he had done a sprint workout the day before. (Short, near-maximal sprints are how to train AnC.) In the days following a sprint workout, AnC is noticeably reduced as the system recovers. The large shift to the right was then an unreliable measure of aerobic fitness, because his AnC was temporarily weakened. Further supporting this was that peak lactate between the two tests had been halved.
Again, weakening the AnC had let the AeC side of the tug-o-war gain ground.
THREE
A couple race seasons ago, I was getting tired toward the end of the season, but I wasn’t losing any speed. Out of curiosity, I did a lactate test. The maximum lactate that I could produce was half of what I had going into the season.
Racing and threshold workouts was gradually weakening my AnC. In this way, intentionally lowering AnC could be used as a way to get some free speed at ~2 mM (~AeT).
I’m suspicious of claims that appear not to be backed up by standard practice…
Don’t judge a philosophy by the crappy website… Lactate.com is a badly designed website with a lot of run-on writing, but the background of the information comes from Jan Olbrecht. Olbrecht has advised on the training of world champion swimmers, triathletes, motocross riders, and runners. At the 2004 Olympics, 40 athletes were training under his supervision. They came home with 27 medals. Also of note, Bow Bowman used Olbrecht’s ideas to train Michael Phelps, whose longest event was only seven minutes.
If you want to get down into the weeds, I recommend reading (and rereading) Olbrecht’s book, The Science of Winning. You may also want to check out writing by Renato Canova, Yuri Verkhoshansky, and Steve Magness.
I think I’ve answered your first question, but that still leaves the second:
What does it mean to have an Anaerobic capacity “optimized” for a particular event (neither too high nor too low)? Again, how does this work at the level of cells/energy systems?
I don’t remember what the cellular changes are, but it’s described in Olbrecht’s book. As far as AnC optimization goes though, it depends on the length of the event and how stochastic the event is.
At two hours and longer, athletes need to contend with glycogen depletion. If depleted, our brains will force us to slow down. To postpone that as long as possible, you’ll want an aerobic capacity as high as possible. That needs to be reconciled against the event-specific need for AnC: How stochastic is the event?
If an event is entirely steady state, then the need for AnC is low. It could be argued that AnC shouldn’t be trained at all, especially if the event is quite long. For example, non-competitive mountain sports don’t require any AnC. They’re very long events with no competitive need to go above aerobic threshold. (The one factor though is that training AnC early on in a recreational program has other benefits.)
In contrast, if an event requires repeated power surges or a final kick to the finish line, then AnC is required. Cycling, skimo, and nordic skiing are great examples.
How much AnC? To be honest, I don’t have a lot of experience figuring that out. That’s my current focus. At the moment, it seems that you want as much AnC as possible without weakening AeC.
And the reason you don’t want to weaken AeC? Another important function of AeC that isn’t widely discussed is the aerobic system’s role as a “vacuum cleaner” for the blood. The higher the AeC, the more that the aerobic system can draw lactate back into the muscles and use it for fuel. The more lactate the aerobic system can use, the more it can consume, the lower blood lactate levels will be or the faster they’ll be lowered, and the more often anaerobic bursts can be used to competitive advantage.
I hope that helps.
Scott S.
