My question is should I try this outside again or do I need to work on muscle endurance?

If your last AeT test was outdoors, I would recommend doing an outdoor test for consistency and tracking progress with your AeT.

I’m just having a hard time believing I’m not within 10% after 6 month’s of continually zone 2 training getting an average of 4hrs or more a week in.

Uphill Athlete recently shared (on Facebook/Instagram) an experience of a member of this community on ADS. It took this athlete a year to go from an AeT of 135 bpm to 170 bpm. Progress will happen, but the timeline will vary by individual based on their baseline, training volume, fasted training, etc. and other factors unique to the individual. You might find this discussion helpful –

Fixing Aerobic Deficiency general timeline? tips?

Scott shares examples of volumes and timelines in the above forum discussion.

I know you say not to do any ME workouts in until within 10% but being so close is there any harm in doing them?

Do you have an event/trip coming up? If yes, then include Muscular Endurance (ME) in your training as it will help with your event. If not, doing ME workouts now will not be as effective as doing it when you have AeT within 10% of AnT.

When does one know if they no longer have ‘ADS’ (aerobic deficiency syndrome)? Is an AeT within 10% of AnT the best metric?

I don’t know if this is the best metric, but UA coaches have used this approach and see it work for all levels of athletes. As a recreational athlete, for me, that’s good enough. Keep it simple.

An alternative method used on TP is to determine your current AnT and then take 75-85% (ie ~80% goal) of that (your running Z2 or aerobic zone) and confirm there is a <5% drift while in this zone for an hour. Which is best? Are there others?

These methods rely on population averages. Just like saying max HR is 220 – age. They assume everyone is identical in the population. The training peaks method would not be accurate for a person without ADS as it assumes a bigger gap than 10%.

Take, for example, an athlete with an AnT of 185 (like the above poster). TP suggests their AeT would be 138-157 which would be 17-34% gap. If that athlete was within 10%, their AeT would be >=168

If its your legs failing first, I would definitely retest with sufficient recovery.

Are you doing strength workouts currently or just just running?

Thank you for the info Sashi and Lindsay.

Scott’s past post that you linked was what I was looking for in regard to time/volume.

On a separate note, I believe (but am unsure) that there may be different paths to achieving the ability to perform within your aerobic zone without drift or decoupling, versus raising your AeT. I assume achieving latter would by default achieve the former, but am not sure the opposite is true. (Not sure if there is an answer to this question or whether or not it really matters–more just thinking out loud here)

Do you have the TFNA or TFUA books? If so, I can point you to pages, or here is a link to the general strength exercises. The idea is to do it 2x per week https://uphillathlete.com/general-strength-routine/

Thanks. Understood.