Part 1 and 2 were tough for me. I could not really draw any useful information from these. Part 3 was different, this unpublished study is a real highlight. Unfortunately he does not give more details on subjects and results. This change% chart is a little bit useless for me. I wish he had shown other results (even though they did not differ between groups).
What were you take aways/learnings from this video series?
First 5 seconds typically are overloaded…
Does this mean hard-start 30:15s – 5s@150% + 25s@120%?
30:30s tend to bring you into threshold zone but not higher (unless you really CRANK the work bouts!)
This is exactly what happened when I experimented with 30:30s (Sleeping Beauty @115%) so I returned to longer steady state intervals. When I get back in the game will definitely experiment with the first point to see if it’s true (for me).
I think this would be about right, the only data that’s specifically listed in the examples video is ‘hitting 160-170% MAP then dropping down to ~140%’
Ditto on Taylor -2 for me just a bit ago. HR was mid Tempo for me even at the end of the last kick on each set. I see how these are considered easier, and may in fact be too easy for me on their own.
In my current plan, that workout serves as the first step in progression, so it’s probably fine in that perspective. But I see more demand and what I expect from VO2 work with the 90 second and longer efforts. Even the descending ones like Mills, which I think is a pretty effective style for my needs.
A lot of this has been covered (the intervals at 90% HR VO2 Max) by Jem Arnold on his Spare Cycles blog. I also created a workout in the workout creator based on Jem’s workouts that he posted.
It’s hard start intervals with steadily decreasing power (but not to big of decreases) so that you keep your HR up in the 90% zone.
https://www.trainerroad.com/cycling/workouts/369021--ronnestad-vo2-heart-rate
Ummm…or you could just ride the snake! 
Be a believer!!! 
It’s not that difficult, especially with all the ‘off’ bits. I’ve done my own version of RS as a solid steady state interval…it get’s a bit rough near the end…but still very doable! 
Give this a shot. Work intervals are set at 115%, but feel free to up them. Even though the TSS and IF are the same as Rattlesnake, I wonder if this would be more difficult for you.
https://www.trainerroad.com/cycling/workouts/482185-10x2-min-vo2s
Not sure why, it’s custom, but I thought all of those were public if linked to. FWIW, it’s 10x2min @ 115% with equal work to rest ratios. 1 HR / 81 TSS / .90 IF
To see custom workouts I believe the creator has to put them in a “Team” (link found on user homepage) and the viewer has to join said Team. My knowledge may be outdated; check with IT.
As for this:
In regards to Seiler’s HR recommendations, what do your levels get to doing this workout?
The Rattlesnake mod w/o I did was 3x8min @ 118% (average); 10min rest…so maybe too much rest(?), although HR still went >90%HRmax. Ah the mysteries of individual physiology! 
Wow 33m at 90%HR+. That worked! I will have to give short 30/15 a try. Not so easy to do outdoors though.
For outdoor workout you need either longer hill or you might try 40/20 and during those rest intervals turn around and go slightly back (hill still preferred). However, you need good brakes and some sharp cornering skills as there is not much time 
I haven’t done it yet, but I typically find VO2 intervals that exceed 2min in duration to be really difficult as long as the intensity is around 120%. It’s hard to pinpoint the reason. Current FTP a touch too high, too early in the season, not well-rested enough, etc. This season I’ll be incorporating a lot of of the 30/15’s or 40/20’s as CX season nears. The Rattlesnake looks like a tough one!
Also intersted in doing the classic 4x8 Seiler intervals. Plan is to start at 105% of FTP. Dicks -2 looks like a good starting point.
My HRM is 191-93 and LTHR was last tested at 175 BPM. Same boat as you. What exactly is your question?
My quick takeaway from the 3-part videos is that intensity, ie. %VO2max (I think Seiler described it really well as “what the cardiovascular system sees”) and workload, ie. avg power, or work above threshold (kJ) can be manipulated separately to achieve at least roughly the same outcomes (or at least acute physiological response) looking at group means.
Would be very interesting and more helpful to us as individuals if we could see individual responses to either intensity- or workload-optimized conditions. Do athletes of different phenotpyes (eg. more “anaerobic” vs. more “aerobic” athletes) respond better to one vs the other?
Then can we manipulate our training to prioritize either intensity or workload to specifically address our physiological weaknesses? Or reinforce our strengths? Or maybe just depending on our goals and demands of our target races/events?
Summary:
Jem
The “thresholds” are artificial constructs. Physiological adaptations are on a continuum. Seiler’s conclusion is that athletes “solve the equation” a little better with the 8 or 16 minute intervals. At 90% of HRmax they can put more work in over the weeks/months/years. The 4 minute intervals had the biggest failure rates.
It’s good to listen to the Fast Talk podcast where he puts a lot of this in context.
The nice thing about the podcasts is that you see that it’s not all black and white. Race specificity counts, and periodization counts. One isn’t going to do 4x8s 52 weeks per year.
I would think power is also important. I have no idea because I’m not a scientist, but I would guess different things happen when you’re working at 120% of FTP @ 90% HRM vs riding at FTP @ 90% HRM. Ventilatory rate is one of the things I pay attention to. Even at 90% of HRM, I’m not huffing and puffing when I’m doing threshold work. However, when I tap into VO2max power I’m definitely huffing and puffing.
I don’t find HR that useful. Maybe it’s just my physiology but I can do the same TR indoor workout twice just one week apart and see 5-10bpm difference during Identical intervals. Temp? Caffeine? Sleep? Hydration? Who knows.
‘Thanks’ for that suggestion! 
https://www.trainerroad.com/career/alexgold123/rides/73630550-rattlesnake-1
But seriously, 'twas a good workout. I found Mills/Spencer harder (I think!), and it seems to hit all the recommended zones from the above lectures 
Turning around twice in 20 seconds seems tough. Unfortunately, steeper hills keep you from getting enough rest during the rest periods. Fortunately, I have a 1-2% grade path around here that’s great for 40/20s.
