Last Sunday, I took part in The Great South Run. This is a 10-mile road race on an absolutely pancake flat course.
My equipment is all Garmin (Fenix 6, HRM-Tri) and i have Garmin’s “Running Power” data field set up. Essentially, I have data for pace, heart rate and power when running.
I ran a good (for me) race and my heart rate was above my Lactate Threshold for the whole of the race (so I was prompted to revise it upwards).
What I find puzzling is that my Pwr:Hr decoupling only appeared to be 0.9% for the whole run!
The power, pace and heart rate all appear to be where I’d expect them to be (i.e. Threshold), and I couldn’t find any evidence of “dodgy data”, so I find the lack of decoupling at this level of effort a bit puzzling.
Can you post the file? Decoupling only shows HR drift wrt power. If your HR started high then it may just have been stable at that high rate all the way through the race.
If you want to manually check it yourself do the following:
NP/Avg HR for first half of ride = A
NP/Avg HR for second half of ride = B
Then ((A-B)/A)*100 = decoupling percentage
The first screenshot shows that it took my heart rate about 7 minutes to settle. So, following your suggestion, I set the start of my decoupling measurement to 8 minutes and then took it all the way to the end of the run. The decoupling worsened, but only to about 2%.
So, it would seem that my heart rate was pretty stable, and well aligned to my power output, throughout the race (as you say).
Okay, that makes sense. I understood it is normally tested at around your AeT, so I just assumed it would be worse as you stressed your heart more. I guess I assumed wrongly.
