The PAIN of the 800 meters explained by an exercise physiologist

UP TO 3, means not anything longer than 3. So you're right - you don't want to slow down. The best performances all happen with a fastest last lap - you've provided some examples, and I'm entirely in agreement with them.

The reason to say "up to 3 to 4", incidentally, because I was asked about a range of events - in cycling, you can get away with a more aggressive start because you carry more velocity which means that any reduction in power doesn't affect the overall performance as much. So in speed skating and cycling, shift for ideal pacing from positive to even happens at around 4 minutes. For running, it's 3 minutes. So we are actually in agreement on that one.

Ross Tucker

No, not a full sprint. Not sure where the article advocates that? It would imply that Rudisha should hit the 200m mark in 22.x seconds, and that's clearly not the case.

This quote from the article talks about the balance:

"When you analyze how athletes pace themselves [in an 800], they have to balance two opposing forces to achieve maximum performance," Tucker continued. "That is, they must go hard enough to get the best possible time, but not so hard that they cause this muscle-impairing fatigue."

Ross

Yeah, you'd be correct on that. I didn't comment on the mechanism for the pacing - there's a lot more to it than the aerobic-anaerobic dichotomy.

Chalk that down to artistic licence perhaps.

Ross

Just look at this graph it explains the energy system contributions pretty clearly.

http://www.nordictrackreviews.com/wp-content/uploads/2012/05/graph2.gif

I think that the percentage of fast twitch vs. slow twitch muscle fibers that a person has plays a big role in how they experience running the 800 meters. Speed types often glide through the first lap and hold on for dear life the second 400. Slower twitch runners are literally sprinting the whole way. Both styles can be amusing to watch if not executed well since the 800 can be an unforgiving event.

Ross Tucker wrote:

Yeah, you'd be correct on that. I didn't comment on the mechanism for the pacing - there's a lot more to it than the aerobic-anaerobic dichotomy.

Chalk that down to artistic licence perhaps.

Ross

You're being polite. She just doesn't know that the first lap is mainly anaerobic. I don't think many runners and coaches do either, because it's the opposite of what they have been taught isn't it?

Luckily, for journalists, runners, and coaches, physiology knowledge is secondary.

pariah wrote:

Ross Tucker wrote:

Yeah, you'd be correct on that. I didn't comment on the mechanism for the pacing - there's a lot more to it than the aerobic-anaerobic dichotomy.

Chalk that down to artistic licence perhaps.

Ross

You're being polite. She just doesn't know that the first lap is mainly anaerobic. I don't think many runners and coaches do either, because it's the opposite of what they have been taught isn't it?

bigtool05 wrote:

5k and 10k are much more painful than the 800 IMO.

Then you ran the 800 too slow. Go out faster- come back the same.

rekrunner wrote:

Luckily, for journalists, runners, and coaches, physiology knowledge is secondary.

Indeed, cliché and hyperbole are much more important.

Why does cliché and hyperbole come out as clichand hyperbole?

The 800m the body really pulls out it's bag of tricks on energy production using not just oxygen but calcium and other positively charged elements.

Dear Ross et al.,

I am interested to hear your comments on my take on optimal pacing strategies for the 400/800:

http://scitation.aip.org/content/aapt/journal/ajp/81/6/10.1119/1.4803068

(if link doesn't work, you can download paper from here:

http://www.physics.wisc.edu/~reardon/

)

Basic idea is that performance in 400/800 (but not in longer or shorter races) is limited by diffusion (of metabolites, from working muscles).

The toy model in the paper tells me it would be reasonable for a coach to tell a 400m runner to go all-out for the first 20m (not 200m, 20m) of the race, and an 800m runner to go all-out for somewhat less than this.

Jim Reardon

Wisconsin Physics

The key assumption of the model (see Sec. VII) is that the

rate of removal, or disappearance rate, of X-factor is propor-

tional to the amount of X-factor accumulated

low pH increases hemoglobin affinity for these metabolites, so the removal rate does increase. But I don't see how that rate would be proportional to the amount of metabolites, particularly with blood volume and cell counts affecting it. Aerobic fitness is a major factor in 400/800 performance.

It might be thought that one way around this would be to suppose that X-factor production also depends on acceleration

Different phases of acceleration involve different metabolites. Glycolysis doesn't start from rest. The bulk of acceleration is done on stored phosphates and is relatively clean.

A(v) is the rate of production of X-factor and is assumed to be a function of running speed v

The same hemoglobin that removes more metabolites at low pH also delivers more oxygen, increasing the energy available from aerobic metabolism and thus decreasing the anaerobic energy required to maintain a given speed. After 200 or 300 meters, it's likely the rate of metabolite accumulation drops significantly. But the drop is much more noticeable than earlier because it's closer to the limit. The trick is to start fast enough to get that pH down to optimal levels for combined output from all energy systems, "full power" mode if you will, then try to maintain it there without dropping pH too much lower.

The biggest slowdown in 800 meter races is often at 200 meters. The second 200 is much slower than the first - but the third 200 is about the same speed as the second. Fast 800 runners go out fast, then switch into a cruising mode that gets them to 600, then go for broke for the last 200.

"Process A represents the production rate of X-factor, an asyet-

unspecified metabolite that is associated with the cessation

of muscular function when working in anaerobic conditions."

Jim, are you looking for a metabolite to blame for fatigue? Why? Surely the 400 and the 800 require the use of the most powerful muscle fibers first, the ones which become glyogen depleted most quickly? Surely one of the biggest causes of the loss of power at the end of these races is glycogen depletion in the most powerful fibers?

Dear Bad,

You write:

>low pH increases hemoglobin affinity for these metabolites, so the removal rate does increase.

What you are writing is not unreasonable, but there are two difficulties: a. the identity of the "metabolites" is not known for certain, so their hemoglobin affinities can't be specified; b. for the sprints the amount of force generated by the working muscles is sufficiently large that blood flow to these muscles is reduced, perhaps to close to zero, so little (perhaps no) hemoglobin is available to remove metabolites.

In essence you are asserting that metabolite concentrations are determined (even in the sprints) by convection, and I am asserting that they are determined by diffusion.

>After 200 or 300 meters, it's likely the rate of metabolite accumulation drops significantly

We seem to agree on this.

>The trick is to start fast enough to get that pH down to optimal levels

There is no real disagreement here either, except that my review of the literature has convinced me that it is far from unanimous among exercise physiologists that pH (or as I prefer to think of it, hydrogen ion concentration) is the controlling variable, and that therefore I must consider pH as one of many variables that change as "butt-lock" is approached.

>Different phases of acceleration involve different metabolites. Glycolysis doesn't start from rest. The bulk of acceleration is done on stored phosphates and is relatively clean.

I am fairly confident that if you took a pH measurement from the gluteus maximus of a 400m/800m runner at the 50m point of the race, you would find that it has increased from baseline by 0.05 or so. This observation (or, as you say, the observation that "different phases of acceleration involve different metabolites") is one reason I feel I can't think of pH as the controlling variable, but only as one of many things that changes as one moves from "fully rested" to "fully exhausted". I am confident that an 800m runner has, even at the 50m point, moved some of the way from "fully rested" to "fully exhausted" despite the fact the pH of the working muscles has moved further from its eventual nadir.

My comments on "acceleration" are intended to convey that there is no advantage in accelerating slowly to the maximum speed one will attain during the race, as for example distance runners will tend to do when they attempt 800m races until they are coached out of it. One is better off attacking the start, understanding that one will reach maximum speed in 20m or less, and should back off a little then. There is no particular penalty one pays for accelerating quickly rather than slowly.

Dear Pariah,

Yes, I am looking for a metabolite to blame for the limitations to performance in 400m and 800m races.

One has to be careful with the word "fatigue" because there are many types of fatigue, and different writers may use the word in different senses.

I agree the glycogen depletion is intimately related to the sense of exhaustion one feels at the end of a marathon, and is likewise intimately related to the limitations of performance in the marathon.

One argument against glycogen depletion as being the cause of performance limitation in the 400m and 800m (which I sometimes refer to as "butt-lock") is that if you are reasonably well-trained you can run an all-out 400m (to the point of butt-lock), rest for an hour, and then do it again, and hope to achieve very nearly the same time. However, the time-scale for recovering muscle glycogen stores is much longer than one hour.

Also I cannot think of any way that such a short period of exercise as 2 minutes, no matter how intense, would deplete the glycogen stores of a significant number of muscle fibers.

POWERFUL and INFORMATIVE training website :

http://tinyurl.com/ns9xzqu

jcreardon wrote:

a. the identity of the "metabolites" is not known for certain, so their hemoglobin affinities can't be specified;

that's why it's sketchy to make any assumptions about their rate of clearance. I brought up hemoglobin as a reason to suspect it's not calculable.

b. for the sprints the amount of force generated by the working muscles is sufficiently large that blood flow to these muscles is reduced, perhaps to close to zero, so little (perhaps no) hemoglobin is available to remove metabolites.

I'm sure this is not true for 800, but if true for shorter sprints it's interesting, do you have more info?

I am confident that an 800m runner has, even at the 50m point, moved some of the way from "fully rested" to "fully exhausted" despite the fact the pH of the working muscles has moved further from its eventual nadir.

Another possible limiting metabolite is ammonia, which has been hypothesized to cause a sensation of fatigue when it reaches the brain. I don't think it clears much at all during a race.

And of course the quick depletion of stored phosphates counts toward "exhaustion."

IIRC your model had v decreasing fairly steadily after maximum, but this is not typical of 800 races, where the middle 400 is relatively constant, and the decelerations occur between 100 and 200 meters, and around 600 meters, corresponding to changing use of energy systems.

Ross Tucker wrote:

UP TO 3, means not anything longer than 3. So you're right - you don't want to slow down. The best performances all happen with a fastest last lap - you've provided some examples, and I'm entirely in agreement with them.

The reason to say "up to 3 to 4", incidentally, because I was asked about a range of events - in cycling, you can get away with a more aggressive start because you carry more velocity which means that any reduction in power doesn't affect the overall performance as much. So in speed skating and cycling, shift for ideal pacing from positive to even happens at around 4 minutes. For running, it's 3 minutes. So we are actually in agreement on that one.

Ross Tucker

Thanks for clearing that up