Hi, I normally plod along at 5.20min/km. My first Z2 run kept me back to 6.15min/km over 10km.
I presume this is normal but found it hard to run that slow, sore knees and back. Is this normal? And adjustment period?
I’ve found that doing anything different that what you’re used to requires some kind of adjustment. Maybe because your form is more efficient when you’re running your normal pace. I’m not sure about the actual reason, but I have found this to be the case.
From our “Getting Started with 80/20 Training” resource document:
Q: I’m struggling to stay in Zone 1 or Zone 2. Help!
A: This issue is most likely caused by using default or estimated thresholds from TrainingPeaks or Garmin instead of performing 80/20 field tests for running or triathlon to identify your actual threshold(s). Additionally, you must also then change the default zones within TP to reflect the 80/20 zones.
If you are drifting into Zone 2 when Zone 1 is called for, or even having a difficult time reaching Zone 2, this is just fine. While the division between Zone 2 and Zone X (low intensity and moderate intensity) is empirical, the division between Zone 1 and Zone 2 is a best-guess from Coach Matt and David. Both Zone 1 and 2 are considered “easy” in the 80/20 system.
For some runners, Zone 2 intensity is still equivalent to a walk. The good news is that, if it is, it probably won’t stay that way for long if you adhere to an 80/20 intensity balance. Even for slower/less fit/older/heavier runners 80/20 is the best way to get fitter, and as you get fitter your Zone 2 pace gets quicker.
Finally, using heart rate as a primary measure of intensity introduces an increased chance of zone compliance issues, and using pace or power instead is recommended.