I’m trying to use DFA-alpha1 value to train around VT1 on my home trainer using the Fatmaxxer Android app. I have a heart rate monitor (polar H10) and a power meter.
I’ve done a ramp test to find approximately my heart rate and power at VT1 (when alpha-1 reach 0.75)
Then I’m trying to train around these targets, monitoring the alpha-1 value with Fatmaxxer.
I’ve a Polar H10, I’ve taken care to use BLE and there are very few errors during the recording.
I was expecting to be able to reach a value slightly above 0.75 and maintain it approximately above this threshold. This is not what I get. I get a lot of variations, from 0.75 high up to 1.9, despite having a near constant power (no more than 10W variation) and HR. You can see the graph (there’s a 10 minute warming up and 7 minute slow down but otherwise it’s almost at constant power and HR). At the end I tried to stay at the high end of power to see if value would still go up again (it remains below 0.75 except for a small time so maybe it was too hard for this period).
Is is expected to have such variations ? If that’s the case, what should be the goal when looking at alpha-1 value ? Should I try to never go below 0.75 ?
Thanks for your feedback and advices !
You can’t really use Alpha 1 for continuous monitoring. You have to use the HR/Power values found in a ramp test.
You can check a1 as an average to see if your values for a specific day are more or less normal. If a1 looks much lower then normal, it could indicate fatigue.
Now from your graph I would still think that there are regular non-corrected artefacts. Simply because every high ‘block’ looks like it is approximately 2 min wide. And a1 has a 2 min calculation window, so each artefact causes a complete 2 min window to be ‘off’.
Thanks a lot for your answer.
I’ll try to minimize non-corrected artefacts and do a ramp test again.
During this session, I had a very regular HR (no drifting) and decoupling was -1,9%. Can I conclude that I was near the VT1 or at least that I wasn’t training too hard for Z2 ? Or it is not sufficient to conclude ?
Thanks !
There’s no one single easy way, besides a met-cart test, that can exactly point your AeT. But there are enough estimates to make sure you’re in the right range.
The MAF formula of 180 mins age is a very good starting point. Then there’s breathing markers. Learn to pay attention to your breathing and when you do notice a subtle change. As you point out, decoupling is another indicator as is Alpha 1. Lactate is a very good indicator but you need to purchase a Lactate meter and learn how to use it correctly.
Scanning your graph and visually filtering out the blocks caused by errors, the trend seems to hoover an a1 from 0.6 to 0.9 which is OK.
Remember to not focus on the exact AeT target. Anything from 5 - 15 bpm below AeT as target will get you the progression you’re after. Riding through that whole range has the benefit of causing adaptation for that whole range and not only at that same exact spot you might be focussing on.
A number of good coaches will emphasise this point… no need to ride at your aerobic threshold.
That said, Joe Friel will state that you ride at your threshold for the intended duration of your target event, and try keep your HR +/- 2bpm for the full duration (Steady Eddie).
Captures all training data and shows it in a large easy-to-read window on your computer. Useful if you are training indoors.
It has DFA and uses the Kubios suggested algorithm for artificat detection and corrections.
Will capture multiple data sources for comparison. So you can also use it to (for example) compare two heart rate straps to see which may be producing more artifacts.
Kolie Moore from Empirical Cycling repeatedly says ride easy below your LT1/Aet. The intensity doesn’t really matter it’s the duration and volume that matters. Don’t even bother about occasionally going over it provided it doesn’t result in undue fatigue which could then compromise your higher intensity interval sessions.
!