# Aerobic decoupling



## paddy_boy (Oct 1, 2012)

Yo, I just finished an aerobic training ride & downloaded the data into Golden Cheetah (apparently Training Peaks doesn't work on Macs). I recently came across the concept of aerobic decoupling, and was curious what the data would reveal about this ride. According to Golden Cheetah, my Aerobic Decoupling (%): -1.38. Not really sure how to interpret this - is this good or bad? Apparently, if the cardiac drift is less than 5%, that's good; greater than 5% is bad. What, exactly, is -1.38%? And how should I interpret this data in the future? Thanks, any input would be appreciated.


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## kbiker3111 (Nov 7, 2006)

paddy_boy said:


> Yo, I just finished an aerobic training ride & downloaded the data into Golden Cheetah (apparently Training Peaks doesn't work on Macs). I recently came across the concept of aerobic decoupling, and was curious what the data would reveal about this ride. According to Golden Cheetah, my Aerobic Decoupling (%): -1.38. Not really sure how to interpret this - is this good or bad? Apparently, if the cardiac drift is less than 5%, that's good; greater than 5% is bad. What, exactly, is -1.38%? And how should I interpret this data in the future? Thanks, any input would be appreciated.


Basically don't. Its so affected by heat, fatigue, hydration, etc, that aerobic decoupling isn't really an accurate gauge of any kind of fitness. I guess it could tell you a little about how 'blown' you were from a ride but thats pretty evident from RPE anyway. Friel and some other people do something with AD, but I'm not sure its worth pursuing.


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## Srode (Aug 19, 2012)

I've had some negative numbers on the trainer, like -5% range. Like was said, there are lots of factors - that influence it so it's not an absolute, but a guide / something to think about. 

Per Friel, I think you are only supposed to be looking at it when doing base building E2 or Tempo, and once you are into higher levels the <5% no longer applies as a fitness guideline. On harder and longer rides early in the season I've had it as high a 12%, never that high later in the season when I am in better shape.


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## paddy_boy (Oct 1, 2012)

Yeah, I'm definitely in Base mode, and this was a Base ride, trying to stay at Endurance pace or below. I was just confused on what -1.38 means - is that "negative" 1.38, or just 1.38 (which, I'm guessing, would be good)?


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## Srode (Aug 19, 2012)

Negative numbers are better than positive numbers. Below 5 is considered good by Joe Friel and ready to move to the next phase of training according to his books. There's a lot of variables that can make it positive or negative / higher or lower. It's a measure of cardiac drift and uses heart rate and power output comparing the first half of your workout to the second half. I'd have to go back to the book to see how the math works exactly, but you can look it up online or in one of his books. 

Obviously how your body responds to increased load will drive the number one way or another among other things. I'm guessing for it to be most meaningful you would need to say at the same power output for the duration the training period being evaluated.


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## paddy_boy (Oct 1, 2012)

Ok, thanks to all for the info!


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