Lactate threshold = One hour power ?

[Cpro]

I read almost always in the web that lactate threshold is the maximum exertion level an athlete can sustain for approximately one hour. Please let me ask you something. I know lactate threshold is on zone 4 heart rate, but i know in this zone that you burn glycogen, that lasts 2 hours, after that is the hitting to the wall. So the question is, why one hour power instead of 2 hours power that gives you the glycogen that burns in this zone? (Maybe means that lactate acid, dont permit to working in this zone after one hour even you have the glycogen to work on this zone for one hour after the first hour)?

Please help somebody who knows about this.

 

[danfoz]

2 hours is on the long side of glycogen depletion. Could be closer to 90 mins or even 1 hour in an untrained individual. I don't believe there is any correlation to FTP. Maybe it's because 40k (25mi) is a pretty standard length TT and takes roughly an hour for a well trained individual? I don't think that's the answer either but maybe someone else knows.

I'm thinking if it were up to the Marquis de Sade it would have been 2 hours, right after you got your hand flattened with a hammer during an episode of buggery. TMI? /img/vbsmilies/smilies/wink.gif

 

[swampy1970]

1 hour power is called 1 hour power for a reason - ie you can sustain it for 1 hour. If you could sustain it for 2 hours then it'd be your 2 hour power. The difference in power between the two isn't huge but there is a difference. Its similar to how you can do a 10 mile time trial at a higher intensity as a 25m TT and there'd be no way that you could normally extend the effort 15 miles despite having lots of glycogen left.

Lactate threshold is a similar concept to 1 hour power but from my experience there was never a nice break point in the lactate curve that just screamed "break point" and you also have to rely on the guy taking the samples knowing exactly what they're doing.

Lack of glycogen is only a problem if you don't feed properly. If you know you're in for a world of hurt from the start of a 2 hour event then phooey on you for waiting until late in the ride to add fuel for the fire...

 

[Cpro]

Guys thanks for your opinions. The fact is that im looking for the reason that causes the one hour power. Is this reason the depletion of glycogen or the levels of lactate in the blood that causes the end for this power after one hour. I know that glycogen is enough for one hour, so i think that this one hour power caused by the increasement of levels of lactate in the blood this levers that cause the rider to stop his effort. Practical a rider in zone 4 could be for 2 hours, because after that 2 hours the glycogen depletes is that right or wrong?
So a rider that runs to TT, after one hour maybe the leverls of lactate could increased enough to force stop him, but after a little time after his blood cleans for this lactate threshold he could succesful stay in this zone for another one hour before the final end of glycogen? (is that right or wrong with this)?

 

[An old Guy]

My one hour power is limited by my heart rate. At a steady 1 hour effort my heart rate hits its max within a couple minutes of 1 hour and my heart rate and power are very difficult to control after that. But until the last couple minutes all feels really good.

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The various testing methods for 1 hour power seem to disagee enough that you could use your 1 hour number from one of the methods for 2 hours on a different method. I would not put too much faith in a number. Being 10% is not going to matter much.