Latic Threshold Heart Rate (LTHR) and Coggan Power Zones

Discussion in 'Cycling Training' started by MrPerfect, Dec 6, 2013.

  1. MrPerfect

    MrPerfect New Member

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    Hi,


    I have a little problem. Yesterday me and my friend had to do a LTHR test, and I have read, that you have to do a time trial, where you're riding as fast as you can for 20 minutes. Then you'll find the average heart rate of the time trial and take 95 % of that. That should be very close to your LTHR. Then we would use this LTHR to calculate our heart rate zones for Coggan Power Zones. Me and my friend have done that, and it worked out very well. But underneath is our problem.

    When my friend had to do his first workout after the test, VO2 max (> 106 % of the LTHR) , but he could'nt reach this high heart rate, only for about 25 seconds ... Why not ? Normally are these efforts about 3 - 8 minutes. Is it because the heart cannot reach high bpm (beats per minute) in the start of training or ... ? I really don't no ...

    Please help !


    MrPerfect
     
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  2. RapDaddyo

    RapDaddyo Active Member

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    I think you're mixing concepts. A few clarifications of terminology. First, lactate threshold is used by lots of people for lots of purposes, so to assume that there is a common, universal definition of lactate threshold is incorrect. When I use lactate threshold, I mean the point of inflexion in blood lactate as a function of power (i.e., the point at which blood lactate begins to increase exponentially as a function of power). Yes, you could substitute heart rate for power and get a similar curve, but the transition point is likely to vary quite a bit from day to day.

    You probably don't have a power meter, hence the references to HR. So, you need to recognize that heart rate is measuring only about half of the heart's response to increases in exercise intensity. The other (approximately) half is stroke volume, which is not measured. Little is known about how heart rate and stroke volume respond to increases in exercise intensity (e.g., Does one or the other respond first or do they respond simultaneously in lock step? Do they always respond in the same way?) You also need to recognize that the exact same intensity of effort on different days or even on the same ride on the same day will produce different heart rates. All of this is to say that one needs to be careful about attributing too much precision to heart rate as a function of exercise intensity.

    Finally, most of your data points are derived from power profiles of a standard benchmark athlete. For example, I have a relatively high anaerobic work capacity relative to my functional threshold power, so I don't fit the 60MP = 20MP*0.95 rule you reference. Even so, you're going from a 20min MP test to a 60min MP estimate to a VO2MAX estimate (e.g., 5min MP) using power benchmarks and then applying that to HR. Your friend would be better off to simply test his 5min MP. Have him start off with an effort at ~95% of his MHR. If he can hold that intensity for longer than ~5min, it's too low. If he can't hold the intensity for ~5min, it's too high. Have him make small changes (e.g., 1% at a time) to home in on the right HR that he can hold for ~5min, give or take about 30secs. That will give him a good VO2MAX training target, which is the ultimate objective.
     
  3. MrPerfect

    MrPerfect New Member

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    Thank you, RapDaddyo ! A very good answer ! It seems to you know much about this.

    I know, that heart rate are'nt the best to training compared to power meters ... but power meters are very expensive ... It would have been wonderful with a power meter, but ...
     
  4. RapDaddyo

    RapDaddyo Active Member

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    I understand the reluctance (or inability) to spring for a power meter. There is an alternative: perceived effort. And, you can use speed if you have some long climbs available where you ride. And, there is a very simple rule for riding at an intensity of effort that will produce the desired adaptation and yet not become a drudgery. You want to find (e.g., by trial and error) your maximum constant intensity for a given duration. Then, for routine training, back off a little (e.g., 10%). So, for example, if you can find a long climb at a relatively consistent grade (e.g., 6%), find out by trial and error your maximum average speed for the climb (e.g., 12mph). Then, for regular training rides, ride the climb at about 90% of that speed. You can apply the 90%MP rule to almost any duration.

    And, when you can afford it, get a power meter...
     
  5. MrPerfect

    MrPerfect New Member

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    Right, but no climbs available :( ... I the future, I better buy a power meter.
     
  6. jhuskey

    jhuskey Moderator

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    No climbs? That is just not natural.:)
     
  7. MrPerfect

    MrPerfect New Member

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    Living in flat and boring Denmark :( ...
     
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