[Scott Johnston]

Pete:

Sorry to be slow getting back to you.  We’ve been swamped.  There is a lot to unpack here but I will try to be succinct.

The test itself sounds like it was conducted using a pretty standard protocol.  However, I can’t see the data or even the lactate numbers so don’t know what they were doing to determine those zones for you.

I value field tests and experience in everyday training far more than lab tests. These values change based on recovery state on the day. They are not fixed in stone.  This lab test is like a snapshot on a single day.  IMHO your experience out training and using the simple field tests we recommend which can be repeated for free anytime you see changes in performance outweigh the lab unless you can get into the lab regularly.

For determining the second threshold  I MUCH prefer to use a field test like a 30-45min time trial to find the average speed/average HR the athlete can maintain for the duration top determine AnT/LT2.  This is an actual performance test and your average speed and/HR are a true indication of your maximum sustainable output.  Where as in that lab you are transitioning through that intensity for only 4 minutes.  That may coincide with your maximum stainable pace but in my experience is over estimates it because you can be comfortable for 4 min at a higher speed than for 40min.

In your case the Z3 spread is only 7 bpm which is outstanding but comes with a significant caveat.  No doubt your paces at AeT and AnT are also quite similar.  This means that while the metabolic load at the top of Z2 is still quite aerobic the neuromuscular load is almost the same as at AnT.  Check the paces you are running at these two points during the test and see if they are also only a fe percent different.  The well aerobically trained can’t constantly train at AeT because of this mechanical stress from the high speed.  Z2 training needs to be more carefully controlled and applied for these fit athletes as opposed to the less well aerobically developed who can train a very high volume of Z2 because they are moving much slower and the mechanical stress is a lot lower.

Now, this is not a definitive diagnosis because I do not have all the information. But, it might help you understand the test better.

From what you say, chances are that you can’t run daily for hours at a time at this new AeT they have assigned you.  While that HR/pace may indeed reflect your metabolic state that corresponds with the top of Z2 you would become overtrained in a couple of weeks training in that Zone.

This is something I have spoken and written about extensively but with all the hype around Z2 these days I have no heard one of the ‘influencers’ mention this little but crucial detail.

I hope this helps and sorry again for the slow reply.

Scott