What does it mean when people say a 10k is 90% aerobic?

It means that a lot of people try to understand energy systems through a simplified version of the oxygen cycle, positing that there's a dividing line between aerobic and anaerobic energy production. (There isn't.)

So, how should we define the energy production in a 10k, or any other race?

Much, much better wrote:

It means that a lot of people try to understand energy systems through a simplified version of the oxygen cycle, positing that there's a dividing line between aerobic and anaerobic energy production. (There isn't.)

Perfect. I think they could mean 10k training deamands a 90% focus on aerobic development, and only 10% anaerobic, but I like this explanation better.

I think it means that 90% of the energy requirement of the race is provided through aerobic pathways (mostly aerobic glycolysis + a little fatty acid metabolism).

They are talking about energy production and how the energy is produced.

The longer in duration the run, the more and more aerobic glycolosis (the process of energy production using the O2 you breathe)is utilized. Anaerobic glycolosis occurs simultaneously, although it's production is less during less intense, longer sessions. That's simplistic, but sort of accurate for what you're looking for.

Think of it like a teeter-totter. The longer you run, the higher the aerobic side rises, yet there is still some height (usage) on the anaerobic side at all times.

Maybe someone can do a better job, but this is the basis of what they're talking about when people name %'s.

ultra wrote:

I think it means that 90% of the energy requirement of the race is provided through aerobic pathways (mostly aerobic glycolysis + a little fatty acid metabolism).

I think that's true in a marathon, but surely in a 10k we use mostly lactate as fuel?

so wouldn't it be more true to say that a 10k is 90% anaerobic?

konfused wrote:

ultra wrote:

I think it means that 90% of the energy requirement of the race is provided through aerobic pathways (mostly aerobic glycolysis + a little fatty acid metabolism).

I think that's true in a marathon, but surely in a 10k we use mostly lactate as fuel?

so wouldn't it be more true to say that a 10k is 90% anaerobic?

No, lactate as a fuel source is still oxidized.

The correction answer is that 90% of the ATP produced comes from aerobic metabolic pathways (fat or glycogen oxidazation).

So in other words its more anaerobic than anything below 10k including 800m maybe even 400m!

Its the same as saying the marathon is more anaerobic than an 800m!

Energy Source Comparisons for Middle Distance

and Distance Events

“Classic” Model

Energy Source 400 800 1500 5000 10000 Marathon

Aerobic (%) 18.5 35.0 52.5 80.0 90.0 97.5

Anaerobic (%) 81.5 65.0 47.5 20.0 10.0 2.5

“Current” Model

Energy Source 400 800 1500 5000 10000 Marathon

Aerobic (%) 43.5 60.5 77.0 94.0 97.0 99.0

Anaerobic (%) 56.5 39.5 23.0 6.0 3.0 1.0

*The “current” model was determined using the latest methodology in oxygen kinetics, and with a much more elite subject population than the “classic” model.

It means they're ignorant. Running a 10K is at least 95% aerobic. No way you can run the last 1000 meters at anaerobic intensity (meaning at an oxygen deficit).

hypnotoad wrote:

It means they're ignorant. Running a 10K is at least 95% aerobic. No way you can run the last 1000 meters at anaerobic intensity (meaning at an oxygen deficit).

Speaking of ignorant, how about that math of yours.

Um, its possible to run using energy from both anaerobic and aerobic pathways at the same time. Saying a 10k is 90% aerobic doesn't mean you run 90 percent of the race aerobically and then 10 percent of it anaerobically. One has the capability to produce a certain amount of energy from anaerobic pathways and one could spread out the usage of this energy in many ways over the course of the racing distance. The percentages just have to do with how much energy used in the race comes from each energy system.

Energy Source Comparisons for Middle Distance

and Distance Events

“Classic” Model

Aerobic/Anaerobic(%)

400m 18.5 81.5

800m 35.0 65.0

1500m: 52.5 47.5

5000m: 80.0 20.0

10k: 90.0 10.0

Mara: 97.5 2.5

"Current" Model

Aerobic/Anaerobic(%)

400m 43.5 56.5

800m 60.5 39.5

1500m: 77.0 23.0

5000m: 94.0 6.0

10k: 97.0 3.0

Mara: 99.0 1.0

*The “current” model was determined using the latest methodology in oxygen kinetics, and with a much more elite subject population than the “classic” model. Data from 1990-2006. From Chapman's ppt.

luv2run wrote:

konfused wrote:

I think that's true in a marathon, but surely in a 10k we use mostly lactate as fuel?

so wouldn't it be more true to say that a 10k is 90% anaerobic?

No, lactate as a fuel source is still oxidized.

The correction answer is that 90% of the ATP produced comes from aerobic metabolic pathways (fat or glycogen oxidazation).

Luv2run, surely in a 10k, we don't burn any fat at all?

As for the glycogen oxidation, surely Lactate is the main intermediate substrate?

I realise that Lactate is converted from Pyruvate, and back into Pyruvate before it is oxidised, however, there is a huge difference in the levels of blood lactate circulating in a 10k compared to a Marathon.

In a Marathon presumably Pyruvate must be the main substrate, with perhaps (my guess) 30 -40% of the Pyruvate being converted to Lactate, and the other 60-70% not being converted to Lactate before it is oxidised.

I am just trying to make sense of the data available, which is difficult since everyone blathers on about Lactate all the time, with very little research and discussion about Pyruvate.

Can you or anyone else shed any light on this to help us all gain an understanding of what is really going on in the muscles and how best to train the different energy pathways?

I know that the best coaching methods are way ahead of scientific research, but the terminology; Aerobic and Anaerobic seems to cause more confusion than necessary.

Any data, references or discussion please?

Better version wrote:

From Chapman's ppt.

who?

Those figures, if they refer to fast and slow glycolysis, just don't make any sense at all.