Tuesday, September 01, 2009


Joe Friel has written lately about decoupling. That's when you're exercising aerobically (at sub-threshold) and your heartrate is not consistent with your power output. I used to use a coupling test when I was training for triathlon. I'd hold my heartrate constant while running on a track. The further I had run after 20 minutes, the more aerobically fit I was. I was amazed at the variation throught the trainign season back then (2001).

So I decided to do a coupling test on the bike yesterday. I put on the heartrate monitor, warmed up, and did 30 minutes at tempo (225 watts for me). I felt nice and steady for the whole interval and was on Hwy 11, which is flat. Wind was minimal.

The ride felt very consistent, so I was surprised to see later that my heartrate gradually rose during the interval, starting in the low 140s and finishing around 150. My threshold HR is about 160. I sort of had a plateau in the middle, but it didn't last.
Supposedly this means that my aerobic system is not well-developed at the moment. I look forward to doing more aerobic work during the fall and winter to see if I get a more coupled 30-min tempo result. If that does happen, maybe I can use this very easy test throughout the season to monitor my aerobic fitness and do more aerobic work when I see things start to "come apart."


Walker said...
This comment has been removed by the author.
Walker said...

[messed up first comment]
I see what you mean by de-coupling, but the summary on the left only says 3-4% which is under Friel's 5% target. Of course I've also found that sometimes selecting a slightly different area gives a totally different number so perhaps visual inspection is good too.

Robert Jordan said...

I need to read more about what Friel has to say. I threw out the first 5 min of HR data of the 30 min. My HR was about 143bpm at 5min in. At the finish, it was 155, so that's (155-143)/143=.084 or 8.4% if you look at it like that. It just seems that I shouldn't see such a steady increse in HR for a sub-threshold effort. I plan to look into it further, do it again with better warmup, do longer test, etc. to figure out what's happening.

Walker said...

Thanks for posting this though. I'm looking back through Friel/Coggan. Friel says you can use a test like this to determine when your aerobic base is established and your ready to move on to the build phases.

I'd like to figure out exactly a protocol to use for the test (like you said) so I can see it in action.

I guess the best way is to do what your doing - multiple tests at different settings while taking into account where you are in your training cycle.

Robert Jordan said...

Now that I've studied Friel's publications more, I see that my method of calculating my "8%" decoupling was not legitimate. But there is still significant decoupling going on. More study will bring things into focus, I guess. Where can I read exactly how the WKO Pw:HR function works? Does it divide the selected interval into two halfs, take NP/ARH for each half and calculate percent change?

Quentin. said...

I am sure you have but it's worth weighing yourself before and after a "decoupling assessment" to make sure that ALL fluid lost was replaced. I've tested this and taking on say 50% less fluid than has been lost has a very significant effect on HR.

Keep up all the good work!