After reading both books, I started looking all over uptown Manhattan for suitably steep slopes for sprints.
Eventually, I figured out that there are free apps for my Android phone to aid in the process. The one I currently use is called Clinometer.
In the meantime, I have done a few HR drift AeT tests on the treadmills in the gym, since my gas exchange test results produced more heat than light.
I had read claims on other forums that treadmills (presumably the same could be said of stairmills) are notoriously inconsistent with respect to pace. I.e., there is a lot of variability on a single machine over, say, an hour. Just because you set it at 3.3 mph, doesn’t mean that it isn’t going BOTH faster and slower than 3.3 within that hour.
I have not tried to verify this by, for example, looking for some identifying mark on the belt and measuring its cycle time over an hour.
But that got me wondering how accurate the incline readings were. My gym has about 30 or so treadmills, but I only recently discovered that two of them are particularly helpful for my UA ambitions. They (1) have a max incline of 30% instead of 15%, and (2) they do NOT have a 30-minute maximum workout duration.
My earlier HR drift test were involved taking short breaks between the warm-up and the first 30-minute segment, and another short break between the first and second segments.
Last week I used a new (for me) treadmill for a HR drift test. After I completed the test at a nominal 14.5% incline, I took out my phone and measured the incline to be between 11.2 and 11.3%.
Now, it could be that my phone is not accurate, but I have more faith in it than I do in my gym’s maintenance crew.