Today i planned to do a 2 hour outdoor ride, in which i would try to fill the majority of the ride with a structured workout. My goal was 5 sets of over-unders, 12 minutes each, 2 min under’s 2 min over’s. The under’s were basically sweetspot and the over’s were high vo2, so quite a bit wider power-variance in the OU’s than the typical TR workout. Rest intervals were 12 minutes long.
I made it about half way through the 3rd set before my power started really dropping off and i decided i found a good place to back off the workout. Call it failing?
I still felt like i had some more juice in me, and decided to switch up to 30/30s. This felt much more doable and i completed 2 sets of 6 minutes. The on intervals in these 30/30s were high anaerobic.
I basically did two very different workouts in the same workout. I never see any TR workouts like this, and i’m afraid there’s probably a good reason why. So i’m curious if there is any training rationale that might discourage me from doing something like this in the future?
Yes, working out to the point of failure is not the optimal way to train.
You need consistency and progressive overload to best stimulate adaptations that will make you faster. The easiest way to think about this imo is by thinking about tomorrows workout - will you be able to do it, or have you ruined yourself with todays workout.
As @TrekCentury said, it sounds like you still got a good workout in. As @WindWarrior said, it sounds like a tough workout – I’d agree that it would make sense to make it a bit easier next time and then build up from there. And finally, as @JoeX mentioned, consistency is key when it comes to building up your fitness over time, and pushing yourself to the point of failure too frequently can derail your consistency.
My impression reading your post is that you didn’t quite know what you were capable of and set yourself up for failure.
That sounds like a brutal, extremely hard workout. If I take your numbers to ballpark the efforts, let’s take sweet spot as about 90 % FTP and “high VO2” as 115–120 % FTP. Then let’s ignore the sweet spot for a moment. 5 x 3 x 2 minutes = 30 minutes at high VO2max. That is a lot.
That’s 3 x (2 + 2) minutes, so 6 minutes at VO2max with “recovery” at sweet spot. That’s 5 x 6 minutes = 30 minutes at VO2max, which is really, really hard. For example, Monadnock +2 is a PL 7.3 workout where you spend 2 x 3 x 4 minutes = 24 minutes at 115 % FTP. That’s 25 % less than what you had planned. Oh, and your “rest” in between VO2max was at partially at sweet spot. Even without that, this workout and all of the others I am linking to in this post are above average hard.
Another workout is Thumb -2, PL 6.8 with 2 x 4 x 3 = 24 minutes at 115 % FTP. I have not seen a TR workout where you spend 30 minutes at high VO2max (= 115 % and above). One of the hardest I have found was the PL 9.0 workout Cliffe with 13 x 2 minutes = 26 minutes at 126 % FTP. I can picture 30 minutes at lower VO2max (106–110 %) being much more feasible.
Personally, I have not seen (much less done) the types of “over/under” intervals you had set for yourself. The closest are what TR calls floating intervals such as Lafayette +3 (PL 6.7), where you 6 x 5 minutes in total (half at sweet spot, half at VO2max). But here the “overs” and “unders” are much shorter, 15–30 seconds. What you did was much harder.
Summary
I wouldn’t say you failed, you seem to have set yourself up for failure. The total amount of work you wanted to do seems outside of the ability of most athletes (assuming high VO2max = 115+ % FTP). Pushing yourself to failure in training is ok occasionally, but that should be done intentionally and with specific purpose in mind. Otherwise, consistency rules and you should stay away from the boundary of what is the limit of your abilities.
If you want to design your own workouts, I’d consider the following guidelines:
Have a purpose in mind. Why did you want to do the workout? What training phase are you in?
Know your current abilities. If 4 x 4 minutes at 120 % FTP feel very hard, don’t attempt 5 x 4 minutes or 6 x 4 minutes at 120 % FTP next. Work yourself towards it by doing e. g. 9 x 2 minutes next or so. Or do 5 x 4 minutes at 112 %.
Be mindful of the fatigue you incur. If you replaced a Very Hard workout with an All Out workout, you might see very small additional fitness gains, but you will have to pay a price — additional fatigue. That is doubly and triply true if you fail the workout.
Consistency is king. A lot of digital ink was spilled about e. g. polarized vs. sweet spot, but in my experience, consistency has a much bigger impact than details like training distribution. Pushing yourself too hard invariably means that your risk of getting demotivated, sick or otherwise unable to train is much higher.
TR does have a number of workouts combining threshold work with VO2max. If you search for combination you will get many examples. One that is similar to what you did is Junction, which is two sets of 3x5 followed by 3 sets of 15/15s.