Hi @trevor and @ryan - recently discovered the podcast and absolutely love the overlap of hard science and coaching experience. I’m planning out my first organized season of training and have spent a lot of time looking at your base training pathway. Can you give me a little insight into how you reconcile the efficacy of 5x5 intervals with the goal of a polarized training plan? Clearly they work well, I’m not doubting that at all. I’m just working to understand how it all fits together.
My current plan is 3 week progressive overload, 1 week recovery, with my high intensity coming from 5x5 sessions 1-2x weekly and the low intensity in the longest chunks of @stephen.seiler Z1 (Coggan Z2) that I can fit.
Hi @ben.grimmnitz, thanks for listening to the podcast and joining on the forum too! I hope you find a lot of helpful information for planning your first season. It’s an exciting time as you learn what works, how to make adjustments, etc.
With regard to your polarized question, are you asking how a 5x5 session would fit into the 80/20 when that time spent with 5x5 would sit squarely in zone 2 of a 3-zone model?
Your current plan is a great way to start. You will get nice improvements by setting up your structure and keeping consistent with it. Over time you’ll be able to make changes to alter how you provide that progressive overload.
Exactly - I’m enjoying the 5x5 threshold work, but if this is my high intensity work for the next 12 weeks I’ll be purely in @stephen.seiler Z1/2 with no Z3. It seems like it will probably give me great aerobic improvements, but definitely isn’t fitting with my understanding of how a polarized training plan would work.
I loved the video on 5x5s and feel like I’m executing them well. My first full workout got me 20 minutes with HR over 160, but only 13 seconds in excess of my “speed limit” of 171.
What I’m trying to understand is - why are 5x5s for 8-14 weeks a good idea, while sweet spot training is routinely put forth as a poor overall approach on the show?
Yes, totally get where you’re coming from. You will likely find different opinions on this, along with different results in the research, but my opinion on the matter is that I like both approaches and feel they both have their place as long as they are applied correctly.
To your question, I think the sweet spot training in general gets a bit of a bad rap is because it’s so easy to overdo it with that training. If you’re knocking out 1-2 quality 5x5 sessions per week, that’s likely going to give you excellent adaptations because your recovery and the training load/progression is spread over a long time period (which the aerobic adaptations need in order to take place).
If you look at some of the pre-built/templated training plans out there, you might have 2 or more days of sweet spot per week mixed in with some endurance, some sprinting, and some maximal aerobic work in Zone 5+ (5-zone model). It’s all over the place. So piling on sweet spot work in a training block like that will give you tons of fatigue that you never really get the chance to recover from, let alone come in fresh to many of the upcoming sessions.
However, utilizing something like 5x5s as you are, and progressing those over time will give you a tremendous benefit to the aerobic system because you are prioritizing that aerobic system, giving adequate rest between sessions (by applying the polarized concept of a high % of riding <LT1), and realizing the results you’re intending to achieve. In-season, it could look completely different and a polarized approach may be what you end up with if you’re doing Z3 work interspersed with a high % of that low intensity volume again.
Two weeks in and already feeling like I’m getting a lot out of @trevor ’s 5x5s. Did 4 reps day one, two sessions exactly as prescribed in the zwift file on the 5x5 page and then upped the power on my most recent attempt. I expected that with increasing the power from 250 to 255w my hr might exceed the speed limit, but instead I felt strong and had the lowest HR yet. It’s almost as if planning out training with an intentional mix of intensity and endurance resulted in improved fitness…
HI @ben.grimmnitz Thanks for listening to the show and for giving the 5x5s a try. Ryan pretty much covered it, but I’ll just add that the 5x5s fully fit into the polarized model as your high intensity work. We’ve covered this in a few shows but we can’t be black and white about lines and feel that if we drop 2 watts below what we measured as our VT2, then we’re suddenly fully in zone 2. It’s the intent of the workout that matters and while the 5x5s should be done right around VT2 (often a little higher) they are a true zone 3 workout.
Keep sharing with us your progress! Glad to hear you’re already seeing results!
My first post on the forum, so I’ll start by saying thanks to the FT Labs team for all the terrific work you do. My question relates to something discussed in both the 5x5 and 4x8 videos. In the 5x5, at 5:25, Trevor compares two WKO files: (1) Rider 1, in which heart rate quickly climbs to target for each interval; and (2) Rider 2, in which heart rate climbs to target more gradually, resulting in less overall time in the target HR zone. The 4x8 video at around 7:40 presents and discusses similar curves. Trevor observes that rider 2 relies more on anaerobic systems, and as a result rider 1 will eventually drop rider 2. But he does offer hope for rider 2 inasmuch as continuing to work the intervals should help build out the aerobic system. My files look a lot like rider 2’s. Wondering if someone could unpack in a little more detail what accounts for the different shape of those heart rate curves, and what (in addition to continuing working the intervals) can be done to help rider 2 get the aerobic system chugging more quickly (if I’m correct in understanding that’s what rider 1 is doing). Among other things, I’m wondering if someone who fits Rider 2’s profile will benefit more from longer intervals where HR sits at target for greater durations, and/or if shorter recovery periods are advised regardless of interval length so the anaerobic system can’t recover between intervals and keep doing the lion’s share of work at the beginning of each interval. Thanks again for all the great insights here.
Hi @cgseldin, welcome to the forum! Great questions. So first, I’ll refer you to the Intervals 101 video where Trevor and I talk about some of your questions in more detail and highlight those two HR profiles where he discusses the differences and relates them to oxygen deficit around the 10 min mark.
Hi @cgseldin, I’ll echo Ryan’s welcome to the forum!
The full answers to your questions are pretty complex and long, but I’ll try to give you the short explanation.
That slow rise in heart rate that you see in rider 2 is called the oxygen deficit (technically not accurate because oxygen deficit comes out of measuring oxygen consumption and not heart rate, but like I said, I’ll give the short version.) Mitochondria in the working cells are what signal the body to increase oxygen consumption. The more mitochondria in the cell, the stronger the signal and the quicker your body increases oxygen consumption when you go hard (i.e. the oxygen deficit is reduced.)
Mitochondria are the aerobic engines of our cells. So, the more mitochondria you have, the better you can rely on aerobic vs anaerobic metabolism and the less oxygen deficit you’ll have.
If you want to improve oxygen deficit, you have to do training that will improve your mitochondrial density. Doing the 5x5s or the 4x8s are some of the best intervals I know to do that. Longer steady base rides are another great way to do it.
I do agree with your point about keeping the recovery short to prevent the anaerobic system from recovering. That’s why I prescribe the 5x5s with a 1 minute recovery, and the 4x8s with a 2 minute recovery. I don’t think you need to do longer intervals than that.
I’m intrigued by both of these sessions and have read the descriptions a few times now.
If we’re doing these about 100% FTP with a ceiling on HR about +1bpm over LTHR, then it doesn’t seem very challenging, and maybe not enough to cause a useful stimulus?
Many of us will have a TTE of 35-50+ mins at FTP, so doing 5x5 (25min) or 4x8 (32min), along with breaks, will still be less than we can already do on any reasonable day - so how do these create an overload and stimulus for adaptions?
I can see how the Seiler ‘max repeatable effort’ versions where people are doing these about 103-108% would seem like a good session, and I’ve done these many times, but obviously they’re a much tougher session.
It would seem that there is a difference between “the most you can possibly do” at a given effort/wattage and the “amount needed to cause adaptation.” So far for me targeting the same RPE and HR has resulted in higher wattage work sets week to week. To be fair, this may have to do with my shorter training history. That said, every workout doesn’t need to be nearing failure to produce benefits and adaptations.
I recall reading a study several years ago that, basically, said that long rides encourage mitochondrial biogenesis and higher intensity intervals (supra FTP) improve mitochondrial respiration. I don’t have the study and don’t recall the authors (apologies). I think it was posted on the Wattage list a while back.
…so I thought I’d try one of these today. Decided to start with 5x5x1 as I think I saw suggested in the original write up. I have a 20 min test scheduled next week after 3 months base work, so thought this would be a good chance to test out some pacing and reacquaint my legs with threshold work again.
My LTHR is about 171-172bpm so I mentally set my limiter at 173 and saw that during the last stages of the last 2 intervals, but it was pretty easy to stay wthin the limits. It was certainly a solid session and I felt it when I’d finished although I haven’t done any FTP intervals for a pretty long time so took a little time to get used to it again. I have a block of threshold work starting next week although its the more traditional 4x8 progressing to 2x20 with 5 min rest intervals.
I’m going to incorporate these into the later part of my season and base next winter and see how they may help build FTP a little more before Build really starts.
Yeah, that’s one of the theories; that volume is associated with increase mitochondrial content (volume density), while intensity may be associated with mitochondrial function (respiration). Although some findings suggest that there is not much training-induced increase in respiration when normalized to the increase in content (mitochondrial-mass specific respiration vs muscle-mass specific respiration).
And finally this recent meta-analysis comparing HIIT and SIT effects on various parameters of aerobic fitness, including mito content (citrate synthase CS activity) and respiration.
I’ve noticed that my heart rate is recovering much faster between intervals on the 5x5 now. I know that this is a sign that they’re working. Would you ever shorten the recovery below 1 minute or increase the wattage used during recovery or is this a situation where you would simply keep increasing the work watts?
Most recent attempt 2/2/22 with increasing wattage (265w for first 2; 270w for third; 275w for final 2) driven by insufficient HR. Despite increasing wattage several times to try to drive HR up, I spent ~13 min HR>160 and only 7min >165. I was breathing very hard, legs were burning, RPE was high, but HR remained lower and was recovering to 130s despite increasing wattage.
Not an expert, but it seems you were struggling to get your HR up, and this is often a sign of accumulated fatigue rather than anything else. Maybe try it again after a few easy days riding and see how it compares with less fatigue?
But hopefully useful for encouraging other thoughts
