Drift testing – observations and questions

  • Creator
    Topic
  • #45288
    Jake907
    Participant

    I’ve done the aerobic drift testing using an inclined treadmill and the Training Peaks app a few times and I’ve come upon two observations with some follow-up questions.

    First, since it’s basically a pass/fail test, you have to have a pretty educated guess where you aerobic threshold is before you start, right? If, for example, I run the test over an hour with a average HR of 125 BPM and a drift of 0.5%, all I know is that my aerobic threshold is somewhere greater than 125 BPM. Am I misunderstanding this?

    Second, I watched Coach Johnson’s video linked below, and the data for the first athlete (beginning around 3:50) looked a lot like the results of the first time I self-administered the test. Basically, I “failed” (drift >5%) despite starting at a really low HR (HR stared in the 120s, ended mid-140s). I repeated the test a week or so later, but I took a longer and slightly more vigorous warm-up so that my starting HR was closer to what I suspected by aerobic threshold was, and I “passed” (HR was high 130s are low 140s the hole period). This makes me think during the first test I was still “warming up” through the some of the one-hour test period. I am doing this wrong? Again, it seems like you need an educated guess where your aerobic threshold so you know at what HR to hit the “lap” button and start your one-hour test period.

    Any thoughts are greatly appreciated. The quality of knowledge you are sharing on this site is amazing.

  • Participant
    Keymaster
    Shashi on #45295

    I run the test over an hour with a average HR of 125 BPM and a drift of 0.5%, all I know is that my aerobic threshold is somewhere greater than 125 BPM. Am I misunderstanding this?

    In this case your AeT is higher than the initial HR (around 120) and not the avg. HR.

    This makes me think during the first test I was still “warming up” through the some of the one-hour test period. I am doing this wrong?

    How long was your warm up in your first test? Did your HR stabilize after warm up? If you can make your test public and share Training Peaks link it will help the coaches to review the tests and provide feedback.

    I did my first AeT test at a target HR using the MAF formula and then made adjustments to subsequent tests till I got HR Drift of <5%.

    Hope this helps.

    Keymaster
    Scott Johnston on #45385

    Jake:

    You’re correct that this test, at least the first time, is a bit of a guess. Shashi’s use of the MAF formula is a good way to get started. This type of experiment (you’re the lab rat) is what is called iterative, meaning you might under or overshoot the target but each test will get you closer. Once you’ve nailed it, subsequent tests will get simpler.

    Scott

    Participant
    Garret on #45390

    One way you can quickly iterate …

    * Find your Anaerobic Threshold HR (HRAnT)
    * Choose a HR that’s going to be below your AeT (HR0).

    Do you first test at a HR (HR1) that’s mid way between HRAnT and HR0.

    If HR1 is too high, then do the next test at a HR that’s mid way between HR0 and HR1.
    IF HR1 is too low, then do the next test at a HR that’s mid way between HR1 and HRAnT.

    Repeat this until you find your AeT.

    Even with a very big difference between HRAnT and your chosen HR0 you’ll find your AeT in only a few iterations. It’s probably better to choose a wide gap.

    For example, let’s say HRAnT is 180, we choose a HR0 of 100. Actual AeT is 156, but unknown when we start.

    Test 1: HR 140 (too low, next test mid way between 140 and 180)
    Test 2: HR 160 (too high, next test mid way between 140 and 160)
    Test 3: HR 150 (too low, next test mid way between 150 and 160)
    Test 4: HR 155 (AeT found .. or good enough for our purposes)

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