Not wanting to spend more time looking at my Garmin than taking in the countryside views, I’ve kept things simple this week. I haven’t done any bonkers sessions with 5000 different intervals, but I have stuck to my zones and brought in a little bit of structure.
When coming back from a big break it’s quite normal to make some big gains in fitness very quickly. Having taken last weeks threshold test on board and ridden to my new zones i’ve noticed some interesting trends when looking at my data.
My first tough session this winter was 2 x 20 minute efforts in Z4. I actually ended up doing 22 minutes for each one because of a damn Strava segment that I was right near the end of. The average power for both efforts was bang on at 358 watts (my anaerobic threshold was 357 watts measured last week). However I only went over my anaerobic heart rate threshold of 161 bpm once during the entire 44 minutes of work. This is unusual as i’d normally accumulate some fatigue or get hot and the heart rate would creep up a few beats. Also, the session did feel a bit soft for what should be quite a challenging ride. This was the first sign that I met have stepped on a little already.
The second sign was during my Z2/3 ride the following day. I spent a total of 40 minutes in zone 3 power during the ride but my heart rate only crept in to zone 3 for 4 of those minutes.
This was also a bit weird so I decided to do a re-test during today’s ride. Now to make sure that these blips aren’t due to power meter discrepancies I decided to test outdoors using the tried and tested method of a 20 minute balls to the wall, flat out effort. Which, to be quite frank, never works for me when it comes to setting training zones. But I did it anyway.
The old rule for the 20 minute test is to take 95% of your average power which should then equate to your current FTP. By last weeks test this meant the target should be 376 watts. Soft.
See the ride on Strava here https://www.strava.com/activities/749473138. I managed 415 watts for 20 minutes with only a small amount of vomit at the end. By the 95% rule this means my new FTP should be 394w. If I were to readjust my training zones to this they would all jump up by about 25-30 watts and i’d probably over train very quickly.
So here’s the reason I believe the 95% rule doesn’t work for me. I’m a big lad with a big anaerobic capacity to dip into when doing performance pieces. This means that if I judge aerobic training zones without taking this into account they are inevitably going to be incorrect.
So what should I do? for me I find the best way to manage this is to set my aerobic training zones (zone 4 and below) by my anaerobic threshold rather than my FTP. Some people consider these to be the same, but you could probably google about 3 different definitions for each one. Now I don’t claim to be a sports scientist, but the definitions that work for me are as follows:
Anaerobic Threshold is the power output at which you start to rapidly accumulate blood lactate.
FTP is your best 60 minute effort expressed in average power.
So if I set my aerobic training zones by my Anaerobic Threshold I can be assured that i’ll be training aerobically and not just accumulating tons of blood lactate. Then for the more anaerobic sessions, Zone 5 and above, I tend to just go as hard as I can for the set session and aim to empty the tanks. This works for me because I really need to improve my aerobic capacity.
So after all that waffle I am actually going to nudge my anaerobic threshold up a few watts to account for the apparent improvements, probably to 370w. I will verify this next week with another BSX insight test on the wattbike.
Here’s this weeks stats:
Same duration as last week, but a higher intensity factor and therefore a much higher TSS. I’ll also be keeping an eye on the Form to make sure it doesn’t drop too low.
Peace out, ride safe and i’ll speak to you all next week!
P.s. As always, follow my program at your own peril and do get in touch if you’d like any help or coaching advice.