D
Donovan Rebbechi
Guest
On 2004-08-28, mirror <[email protected]> wrote:
> Hello,
>
> What is the reason marathon training programs emphasize
> optimizing the fat burning mechanism through long, slow distance?
*Long* distance optimises a whole lot of mechanisms. The main reason
to train "slowly" is that it is hard to train for very long at your
5k race pace (for example)
What it ultimately boils down to is specificity. Simply put, if you
don't do long runs in training, a 20 miler will feel really difficult
even if you only do it really slowly.
> The argument that such optimization spares glycogen during a race
> seems not to hold up. The body stores 2000 to 2500 glycogen
> calories,
Not necessarily. Those numbers assume that you're reasonably well
adapted. It also assumes that you exclusively use aerobic metabolism
to burn that glycogen. Once you start using anaerobic metabolism, cellular
level adaptions play a role. Metabolism becomes a more complicated,
multi stage process, where the initial breakdown of the glucose molecule
does not release all available energy. The better the cellular adaptions,
the more heavily you can use anaerobic metabolism without rapid lactic acid
accumulation.
> enough to make it to mile 20 or 25.
Wrong again. 100 calories per mile is about right for a 137lb runner. If
you're heavier than that, you will burn more than that.
> Since the runner is
> taking glucose on board through sport drinks at fluid stations,
Which cannot be absorbed very quickly.
> it seems likely he or she will cross the finish line with a
> glycogen reserve.
If he/she runs at an appropriate pace, *and* trains properly.
> In fact, the bonk is glycogen depletion, and most training
> manuals contend a runner that hydrates properly (with a sodium-
> glucose solution) will not bonk.
Provided that they pace themselves properly, and train properly.
> When they cross the finish line,
> the wall will still be ahead of them.
>
> Also, competitive marathoners race at paces that demand glycogen
> as fuel.
And distances that require heavy use of other energy sources.
> So, again, what is the value of training slow if the purpose is to
> condition the fat burning oxidative mechanism?
Training *long* is more important than training slowly. But if you try
run your 20 miler like it's a race, you'll be sluggish for 2 weeks, so
it's a good idea to do it slowly.
> Why not train fast to compete fast
That's a fantastic idea, and most advanced marathon training programs do
include speedwork. But you can't have it both ways -- you've got to do
short-and-fast training for speed, and long-and-slow training for endurance.
Attempt to do long-and-fast training, and you will burn out very quickly.
> and take glucose on board during the race to use it as the predominant
> fuel?
A fast marathon runner will use glucose as the predominant fuel regardless.
Cheers,
--
Donovan Rebbechi
http://pegasus.rutgers.edu/~elflord/
> Hello,
>
> What is the reason marathon training programs emphasize
> optimizing the fat burning mechanism through long, slow distance?
*Long* distance optimises a whole lot of mechanisms. The main reason
to train "slowly" is that it is hard to train for very long at your
5k race pace (for example)
What it ultimately boils down to is specificity. Simply put, if you
don't do long runs in training, a 20 miler will feel really difficult
even if you only do it really slowly.
> The argument that such optimization spares glycogen during a race
> seems not to hold up. The body stores 2000 to 2500 glycogen
> calories,
Not necessarily. Those numbers assume that you're reasonably well
adapted. It also assumes that you exclusively use aerobic metabolism
to burn that glycogen. Once you start using anaerobic metabolism, cellular
level adaptions play a role. Metabolism becomes a more complicated,
multi stage process, where the initial breakdown of the glucose molecule
does not release all available energy. The better the cellular adaptions,
the more heavily you can use anaerobic metabolism without rapid lactic acid
accumulation.
> enough to make it to mile 20 or 25.
Wrong again. 100 calories per mile is about right for a 137lb runner. If
you're heavier than that, you will burn more than that.
> Since the runner is
> taking glucose on board through sport drinks at fluid stations,
Which cannot be absorbed very quickly.
> it seems likely he or she will cross the finish line with a
> glycogen reserve.
If he/she runs at an appropriate pace, *and* trains properly.
> In fact, the bonk is glycogen depletion, and most training
> manuals contend a runner that hydrates properly (with a sodium-
> glucose solution) will not bonk.
Provided that they pace themselves properly, and train properly.
> When they cross the finish line,
> the wall will still be ahead of them.
>
> Also, competitive marathoners race at paces that demand glycogen
> as fuel.
And distances that require heavy use of other energy sources.
> So, again, what is the value of training slow if the purpose is to
> condition the fat burning oxidative mechanism?
Training *long* is more important than training slowly. But if you try
run your 20 miler like it's a race, you'll be sluggish for 2 weeks, so
it's a good idea to do it slowly.
> Why not train fast to compete fast
That's a fantastic idea, and most advanced marathon training programs do
include speedwork. But you can't have it both ways -- you've got to do
short-and-fast training for speed, and long-and-slow training for endurance.
Attempt to do long-and-fast training, and you will burn out very quickly.
> and take glucose on board during the race to use it as the predominant
> fuel?
A fast marathon runner will use glucose as the predominant fuel regardless.
Cheers,
--
Donovan Rebbechi
http://pegasus.rutgers.edu/~elflord/
