I've found that it can work, but ONLY if you are taking advantage of the decrease in training speed to gradually but significantly ramp up training volume. Especially for running.

People tend to lose their common sense around this when they first encounter it, because all these folks online are saying 'train slow run fast!", but the (obviously) reality is that if you keep training volume the same but just slow down all your training paces - you're gonna get slower. (duh).

This approach usually pays of spectacularly well for folks doing the first 'big' marathon build, often to 50+, even 70+mpw. At that volume, you're running the large majority of miles at easy aerobic pace (well under the 80/20 fast/slow ratio recommended in some books) but due to all that mileage, most folks go out and crush their 5k-10k-HM race times due to all that new big volume.

I'd guesstimate that you should be getting to at least 25% more volume on average than prior if you are intentionally slowing down your overall training paces, to see improvement. That's just my guesstimate, not a scientific figure.

Obviously, if you're a low-volume athlete (like running <15mpw) then you'll need alot more volume rampup to compensate for the loss of speed in training.

You have to train fast to race fast.

Yes given that 90% of your training is easy, but you have to nail the 10% of speed work. Percentage in time.

I absolutely believe you can get faster just training slowly. In fact, I did it this year. However, I also believe to be the fastest version of your self, you should include work at faster paces/higher power.

How do you define "fast" when you say this?

  
There is no way you have a PB if you never run faster that your race pace once in a while.

The question is what portion of your training should be above target race pace.. 10%, 15% or 30% and how slow should your slow be.

IMO that is very dependent on your fitness and your physiognomy (at what speed you start to produce more lactate, what does your lactate curve look like, etc)


But a lot of people with very strong opinion on this subject (Sweet spot vs Polarized)

My two cents...

"Slow" and "fast" aren't specific enough to describe how we should train. If you tell people to go "slow" or "fast" they can understand that in completely different ways.

My go-to training plan for myself is to put as many miles as i can get in December and January. To get big miles, i can't just go out and do intensity every day; however, if i keep myself in zone 2 i can get 20 or so hours per week for a few weeks in a row without getting sick, injured, or burnt out. That builds a really high TSS, and I've been able to race fairly well for myself in February/March/April when i have a lot of my important races. As I get closer to my races, I start doing less hours and more intensity (faster training). But i wouldn't consider zone 2 "slow." I can hold a conversation in zone 2, but after 5 hours i'll feel pretty smoked. When it comes time to start training zone 4, i find that i can already hit pretty solid numbers in those zones by only doing lots of zone 2. And once i start doing zone 4 work, i find that i get race-fit very quickly. YMMV, but it works well for me.

If i had less hours to train i would increase my intensity. For example, if i had 10 hours per week i would train at a higher intensity (faster) than if i had 20 hours per week. I'd spend more time in zone 4.

The idea that going slow (zone 1) for 5-7 hours per week will turn you into your best self isn't accurate in my opinion. I don't think anyone who know there stuff actually believes that, but I've met people who believe it.

Like others have said, I think there is a balance point in there somewhere. Lots and lots of zone 2 can be extremely helpful, but eventually as you get closer to your event i think training some high intensity will help build speed.

Side pet peeve: people who won't use their big chain ring in the winter time because "training in your small ring makes you fast." I've had to wait for people on many occasions because we have a huge tailwind and they can't keep up because their coach said they can't use their big ring. They are spinning like 120 rpm in their 34/11. If you're in your training zone, who cares what ring you're in? Sigh.

Some of your training should be faster than your race pace. If you want to run at 6 minutes per mile in a race, I would want to be doing quarter miles in under 75 seconds.

This.

I didn't run faster than moderate pace from March until doing a 4 mile time trial in September. I averaged just under 40 mpw. No races since February. I ran the TT at 2.5 minutes per mile faster than my training pace. I regularly ran hilly trails on the weekends, but there was no variation from the moderate pace.

If you're a new athlete who has only trained at one pace, going faster than that pace in a race is going to be uncomfortable, but is certain doable (depending upon the length of the race), assuming that the athlete rested sufficiently prior to the race.

No. It makes you stronger. And if you're stronger, you can swim/bike/run/row/ski the same speed for longer. Which in turn makes you faster if it's a race over 60-90 seconds.
But actually faster. No.

I disagree with this part - "training easy all of the time" - however this was worked wonders for me personally: https://www.8020endurance.com/

I did that, I got really good at running 8:30-9:00 min/miles

i use 80/20 endurance and when im training consistently (not this last stupid year) i absolutely believe in the method. you have to have a high volume of easy stuff mixed in with some all out work, but it will absolutely work and make you faster. i also am 100% injury free since going 80/20, which is huge.

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It also depends on how often you are racing.

If you only race once every two or three months and have a off-season of four months with no racing, that's a very different situation to someone who is racing twice a week, over a variety of distances, throughout the year.

+1 on this.

The first time I trained for a marathon, in 2007 (didn't know what I was doing!) I did a solid amount of mileage and virtually no speedwork for most of the training cycle. Ran a few 5ks between 8 to 4 weeks out from the marathon, and demolished a PB by about a minute on the second one, running 18:15 on the track solo. That was the fastest running I'd done in months (most of training was mileage at 8:00+). You can definitely break PRs in a race or TT context by going faster than you ever did in training.

As another poster said, for most it's not the best way to be your fastest self. But it can be more injury-proof, especially in running.

You need to train fast at some point as you need to train the mind as well as the body. When training fast, you develop mental toughness and discipline as you experience significant pain. You develop little tricks and techniques that help you when you are really suffering. And over time your ability to suffer increases as you find different ways to manage the pain. For example I might be really struggling, but then I will say to myself, "give it 1 more km then you can have slow down", by the time that 1km has passed you might be in less pain or you might be close enough to the end of the run where it becomes psychologically easier to handle the pain.

If you are just training easy, you would never suffer and you would never get the opportunity to train your mind to deal with the physical anguish the body will face. The pain would be unfamiliar and when it hits you like a train the mind would not have the skills to deal with it.

It isn’t about the slow pace itself, it’s the insensity. And mainly because of less recovery, so you Can increase volume instead. So, if recovery time is a limiting factor in adding volume, lowering the instensity and adding volume might be beneficial. If time crunched or already training maximum amount of time available (I mean, work and life matters) and recovery isn’t a limiting factor, then no, lower intensity won’t help a bit, on the other hand - try to increase intensity to the point where recovery becomes a limiter and back it down a little bit, until it’s balanced.
High volume and High intensity would yield far the best results, if you could recover from it.
I Think 80/20 or LSD or whatever is often taken out of context of the big picture.

No, if you train exclusively at an 'easy' pace all of the time you will not miraculously be speedy on race day. As others have said, at least some of the training must be at or above race pace to achieve the physical (and mental) adaptations to be able to sustain a high pace in a race.

The reason for "easy" training (be that 80% easy / 20% High intensity, or any other proportion), is to ensure that you build endurance/strength during easy sessions, but still be fresh enough to really nail the speed work in high intensity workouts. Similarly, training "hard" all of the time is also not good, as it just means you overload with fatigue, leaving you unable to do proper HI sessions well.

I also believe that 90% of GI and cramping issues people have in races (but never in training) are not due to "bad nutrition" (thought some definitely are). Rather, I believe most muscle cramping is caused by the body / muscles' reaction to being pushed to levels of intensity and duration during a race it never sees in training. I.e. People doing nearly all their training at 8min/mile and then wondering why they cramp trying to run their entire marathon race in 6min/miles.

But, if they have done a significant amount of training at 6min/mile or under and their body is adapted to running that pace, they will be less likely to have cramping issues. Thus you need to go fast in training (but not always fast) to go fast in a race.

You have to train slow to race fast

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I’ve trained and been coached several different ways over the years. Whether it was sweet spot training, higher intensity interval stuff like some of EN’s old plans, personalized coaching, 80/20, and easy running.

My personal best 70.3 or IM runs were when I never ever left zone 1 in run training. Run 3 miles... zone 1. Run 6 miles... zone 1. Run 13 miles... zone 1. Lot of that was due to being able to up the run volume compared with other plans that had intensity built in. I ran my best 70.3 run at about 1:15/mile faster pace than I ever saw in training.

Anyone that says if you only run at say 9:00/mile easy pace can only end up running at 9:00/mile during a race is full of shit. I trained for one stand alone marathon in my life. Ended up not racing due to having surgery the week before the race. I was zone 1 all the time coming off an IM build a few months earlier. I was confident I could have run a Boston Marathon qualifying time (or came damn close) despite never running one mile in training at that pace with exception to an 18 mile race sim about six weeks before the race. Granted, anything could’ve/would’ve happen on race day but I ran that race sim at a pace way faster than any training run. I also learned that day that running that pace for a very long distance sucks ass but that was more mental than physical. 😁

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"Anyone that says if you only run at say 9:00/mile easy pace can only end up running at 9:00/mile during a race is full of shit."

Yup, running lots of miles at an easy/steady pace will get you pretty darn fast, I started running in university and went from a walk on former junior hockey player running 41min 10k to a decent running in the 15/32 range running high mileage of around 100 miles per week within 2 years (also lost 35 lbs), I am certainly not the most talented and in fact was one of the slowest runners in my club in the post university track club days back in the 90s. Now running easy/steady I feel will get you 80-90 percent to your potential but you will need to do some higher quality stuff to get to your potential in the 5/10K range, I never ran a marathon outside of IM so not sure about needing quality to max marathon potential. I think the great Ed Whitlock ran close to 2 hours per day at an easy pace and his only high quality was racing quite a bit and he ran 2:50 around age 70 I believe.

I don't think its an easy this or that situation

You will get faster just by running consistently if you are new to the sport and I don't think anyone is disputing that. but only up to a certain point which varies person to person based on "talent". Then you will plateau and to continue to improve you need to either A) increase volume B) increase intensity

So then you can make a claim that if 2 people are training and one does 30 MPW with 2 harder/faster sessions and the other does 100 MPW of only easy runs then they probably will both be improving if before they just did 40 MPW of easy running before. Which strategy works "best" depends on the person and the race with longer races such as ultras, the marathon and half marathons likely benefitting from the high mileage plan and shorter races such as the 10k, 5k and below benefitting from the other plan.

Lydiard said something along the lines of "its not the distance but the pace that limits us". Meaning that if you run slower you are able to run longer and subsequently get fitter and I think that is the claim that your friend may be getting at

I can almost guarantee than the person doing 100mpw consistently, even if all z1-z2 pace, will crush themselves in a race versus themselves training 30mpw and with 2 hard speedwork sessions per week, at all distances from 5k to marathon+. Maybe not in a 400 or even a mile all-out, but 5k+, likely.

At 70+mpw consistently running you get pretty fast even while running zone 2. My z2 runs at that volume felt surprisingly hard, even with HR in check, as you can push the legs so fast and far given your conditioning.

Most folks (esp triathletes) who have never consistently trained big run volume miles of 50+ mpw (esp 70+mpw) assume that it's just as good to do 30-40 with speedwork, but it's typically not. Keep in mind i'm not saying you'll become 2x better by doing big mileage - the gains are real, but modest.

It was literally impossible for me to break a 20:50 5k from age 16-30 because I never ran more than 35mpw, even if I did strucutred book training plans, and raced regularly, and went guts-all out on speedwork days. One 60mpw marathon training cycle (with speedwork to be fair, but not more than before on low-vol) and I went from 21:00 avg to 18:30 in my early 30s in a single training cycle, and not even focusing on shorter distance racing.

It's hard as a triathlete to see this kind of single-sport volume. Unfortunately for me (and most), splitting time between SBR means you never get to this type of volume for any sport, and thus you need training strategies that work with less volume for each.

There are ways to do this. The problem is triathletes think they're training for three sports, not one, and that every workout needs to be a rehearsal for (going slow at) races.

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