"Junk miles" is a vague term. Training is better than not training until you reach the point of being unable to recover properly. Some types of training are more efficient at improving performance, and some types of training are more efficient at improving performance at a specific event distance. Different athletes (i.e. fast twitch dominant versus slow twitch dominant) respond and adapt better to different training intensities. Junk miles is a useless term for thinking about appropriate training.
Jeff Schiebler, former Canadian record holder, ran for a Japanese corporate team, living and training in Japan. He said most of the Japanese runners ran too slow for him in training.
There's another factor with long, slow running. Peter Snell's graduate research indicated that if you run long enough to completely deplete slow twitch fibers, the fast twitch are recruited to help perform the work.
I do remember Schiebler. He did very well and I kind of remember a story claiming that he really struggled with all the mileage his corporate team did and was allowed to skip their first run of the day.
I actually had a fairly long and somewhat puzzling conversation with Peter about recruiting those fast twitch fibres. He told me that to do that you cannot run much slower than seven minutes a mile. He was very firm that you needed to run at least that fast and if you went much slower what happened was that your slow twitch fibres switched over to burning fat rather than glycogen and your fast twitch fibres mostly did nothing.
It seemed odd to me that he was so iron clad on this point. Seven minute pace is different things to different people and often a different thing to the same people in different circumstances. In my best years I almost never ran that slowly. But in high school 7:00 pace was close to what I could run for an all out mile and I'm back to that state now in my 70s. Seven minute pace over a hilly course on a hot and humid day is very different from 7:00 pace over a flat course on a cool, overcast day. Surely those sorts of things must make a difference in terms of what your muscle fibres are doing I told him. But he was adamant. You had to be going no slower than 7:00 pace for this recruitment to happen.
This did not add up for me but I have no credential here and Peter had a massive one so I wasn't going to argue. But I did ask some other exercise phys types that I know, one being our own beloved and now departed John Hadd, and all of them agreed with me, i.e, that it's a level of effort that begins this recruitment of fast twitch fibres rather than a specific pace.
Junk miles exist. But there's no simple or singular definition. They're just miles that don't help you achieve your goals. Someone tried to tell me my evening 15 min shakeouts at 8:30/mile pace after a workout "don't count" and are "junk miles." The shakeout made me feel better and looser and more recovered for the next day, sounds like a win to me.
For trained athletes >50% VO2max of intensity is needed to call it a training. So theoretical this is the lower limit and below that, no training effect (or very little).
However, in practice, for over 99% of all runners, even if they run very slow, it is above 50% VO2max. So you can consider any running mile a training mile or training duration.
The first one is running far too slow. For example if you are a 14:50 5k runner but you run super hige mileage 120-140mpw and log a bunch of easy runs around 7:00/km pace at a heartrate that doesn't even reach zone 2. That is total junk mileage, it does nothing for you.
The second one is very common in people who have just started running. They will be in 20 minute 5k shape but think they need to run fast to get fast, so all their 'easy' runs will be done around 4:15-4:20/km. These are junk miles.
And yet, just about every elite male runner (guys capable of sub 13:20) are running the majority of their miles at this pace.
Are they getting it wrong, and are all the much slower runners getting it right?
I know it's trendy now, but elites tend to do a very small amount of running in "zone 2". If we follow the definition of zone 2 being an intensity just below LT1, then for a 13 minute 5k guy, zone 2 is likely 3:10 - 3:40/km (5:05 - 5:55/mile). Very, very few elites are running anywhere close to this unless it's part of a workout (Graham Blanks might be the only one, but he doesn't upload all of his runs to Strava, so we don't see all of his actual easy days).
Zone 2 isn't the intensity just below LT1. We can't directly compare because Zone 2 is a heart rate zone and LT1 is not a heart rate measurement. But we can look at the %maxHR that most people are around when doing LT1 and see that there's a big gap between LT1 and the upper bound of Zone 2.
For example, for me personally (and these are just estimates, not lab results), my HR is low 160's for LT1. The upper bound of Zone 2 (for me) is mid 130's and lower bound is upper 110's. I typically do my easy runs with HR 120-130. If I'm really fresh and fully recovered, I'm going 7:45 pace, but the day after a killer workout might be 9:00. My LT1 pace for a continuous effort is around 6:00. So there's a massive gap. The only time I run those in-between paces (meaning mid to upper 6's, low 7's) is in the first third of a progression long run.
This gap between LT1 and Zone 2 is widely considered a "no man's land" pace. In other words, if you're running your easy miles faster than Zone 2 but not hitting LT1, you're wasting effort. You ought to be slowing down your easy miles to Zone 2 for the same benefit and less fatigue and wear and tear.
So Zone 2 is the next useful intensity below LT1. But they're not close in pace.
Having said all that, you do hear of world class distance runners jogging 8-10min miles sometimes, and those must be in Zone 1 for them. But the majority of their easy miles that slowly? I don't believe it. Maybe there's someone but that's not the norm. There are some Zone 1 fanatics out there in other sports but it's not a trend that has taken over the training of world class track and road athletes.
I do remember Schiebler. He did very well and I kind of remember a story claiming that he really struggled with all the mileage his corporate team did and was allowed to skip their first run of the day.
I actually had a fairly long and somewhat puzzling conversation with Peter about recruiting those fast twitch fibres. He told me that to do that you cannot run much slower than seven minutes a mile. He was very firm that you needed to run at least that fast and if you went much slower what happened was that your slow twitch fibres switched over to burning fat rather than glycogen and your fast twitch fibres mostly did nothing.
It seemed odd to me that he was so iron clad on this point. Seven minute pace is different things to different people and often a different thing to the same people in different circumstances. In my best years I almost never ran that slowly. But in high school 7:00 pace was close to what I could run for an all out mile and I'm back to that state now in my 70s. Seven minute pace over a hilly course on a hot and humid day is very different from 7:00 pace over a flat course on a cool, overcast day. Surely those sorts of things must make a difference in terms of what your muscle fibres are doing I told him. But he was adamant. You had to be going no slower than 7:00 pace for this recruitment to happen.
This did not add up for me but I have no credential here and Peter had a massive one so I wasn't going to argue. But I did ask some other exercise phys types that I know, one being our own beloved and now departed John Hadd, and all of them agreed with me, i.e, that it's a level of effort that begins this recruitment of fast twitch fibres rather than a specific pace.
Very interesting from Snell. It's funny to me how even those with so much experience and knowledge can still be so dogmatic about things like that. But the point about fiber recruitment is very interesting. I'd be curious about not just pace but also terrain affecting that. If you are plodding along but going up a consistent grade, is that recruiting fast twitch fibers or just giving you a slightly higher HR without the same pace effort?
I think it's also interesting how everyone has their own defined paces for each of these things. For Snell, 7 minute pace is very slow yet I see on Strava many runners at a high level do mileage in the 7s and I've even seen Eric Holt creeping into the 8 minute range recently (albeit at altitude and he may be coming back from sickness). I used to never start my watch on mileage days but would still run relatively fast. This was mostly because other people I liked running with were faster than me so I'd run that little bit faster to have people to run with. But then if I felt wiped after a workout or just in general, pace could slow dramatically.
As I've gotten older (and slower) I've found I can get too caught up in the watch if I wear it too much and start defining my junk paces. This usually leads me to having those tired days and looking down at watch and being mortified that I've slipped in the "inexcusable" junk zone! Part of this is also training solo mostly, as I can slip into over-fixation on pace when I don't have a person to talk to or some other goal for the run besides time/distance. I think the ultimate thing for me personally is how a run feels. If your legs are feeling heavy or unreasonably sluggish yet you feel you need to force those miles in, those are probably junk miles, regardless of pace.
Schiebler ran for the Richmond Kajaks track club, Dr. Doug Clement coach.
I'm pretty sure Clement had run at Oregon under Bowerman. Distance coaching in British Columbia those days was very influenced by Bowerman. Norm Trerise ran and coached Vancouver Olympic Club, the club I raced for. I rarely trained with them as I grew up about 60 miles away. Norm ran at Oregon during the early Pre years. I was running 100 miles a week by 12th grade because I had read a Lydiard training manual. Other Vancouver Olympic Club guys that ran for Oregon, Peter Spir and Art Boileau.
Junk miles exist. But there's no simple or singular definition. They're just miles that don't help you achieve your goals. Someone tried to tell me my evening 15 min shakeouts at 8:30/mile pace after a workout "don't count" and are "junk miles." The shakeout made me feel better and looser and more recovered for the next day, sounds like a win to me.
Just like a slow, short morning run may feel like “junk,” but it’s actually helping with blood flow and recovery and stimulates some hGh production too.
Running is a series of ever increasing stimulus, followed by rest to allow progressive adaptation over time. It really is that simple. Many people could run a lot more than they ever thought possible actually running more “junk” miles and taking the time (not mere weeks but months and years) to build up to each, successive higher level.
There is probably a point of diminishing returns, but that is much higher than probably what most people think. Slow, long running improves running economy too and recruits/establishes more mitochondria, even if it doesn’t improve things like VO2 max. I don’t think people get into trouble so much with overtraining as they do with under recovery.
junk miles and training is anything in excess to get the adaptation you are looking for.
if you are looking for aerobic development, how many miles and what pace causes the greatest effect, once determined, anything over the optimal is junk.
in the case of speed, is it 6 x 200 optimal, or is it 10 x 200, or 30 x 200 (which I did and was way over necessary, message to coach)
to warm up, or maintenance volume and conditioning while you are peaking, this is of course not junk.
anything over optimal is junk. once the cup if full, more is waste.
He was very firm that you needed to run at least that fast and if you went much slower what happened was that your slow twitch fibres switched over to burning fat rather than glycogen and your fast twitch fibres mostly did nothing.
Wouldn't that be what you want, though? Don't you want to accustom your slow twitch to fat oxidizing while running rather than burning through your limited glycogen? I'm not sure why he'd think that's a problem.
For trained athletes >50% VO2max of intensity is needed to call it a training. So theoretical this is the lower limit and below that, no training effect (or very little).
However, in practice, for over 99% of all runners, even if they run very slow, it is above 50% VO2max. So you can consider any running mile a training mile or training duration.
Typically, what hr %ge is 50% of VO2max?
It kicks in roughly around 57% of HR max. Very easy effort... most hit that while cross training, and people who don't run usually get there during a brisk walk.
If you like to run, and you enjoy running any extra miles that had no specific training or goal related purpose, those are not junk miles.
Too many people on these boards seem to only look at running as training for racing or achieving some other goal. If you run miles only as a means to some other end goal, then yes miles that do not specifically help you achieve that goal might be considered junk miles.
Many people get benefits from and enjoy miles run that have nothing to do with training or working toward a goal. They might simply enjoy running those miles, and those miles run become an end in itself. If so, those are not junk miles.
For some runners, miles run are enjoyed and valued as both a means to an end and an end in themselves.
Junk miles are sort of like junk food. Some may consider food to be junk if it supplies little or no nutritional value above and beyond calories consumed. But if you really enjoy eating that food its not junk food. And those 'empty' calories from junk food are still life sustaining and necessary calories that everyone needs.
He was very firm that you needed to run at least that fast and if you went much slower what happened was that your slow twitch fibres switched over to burning fat rather than glycogen and your fast twitch fibres mostly did nothing.
Wouldn't that be what you want, though? Don't you want to accustom your slow twitch to fat oxidizing while running rather than burning through your limited glycogen? I'm not sure why he'd think that's a problem.
As I understand it, fat is a much less efficient fuel source than glycogen. You can run much farther using it than you can go using primarily glycogen but you can't run as fast. So if you're running ultras you'd want to use fat but in a marathon and down you'd want to stretch out your time using glycogen for as long as possible. Again, that's how I understand it.
And yet, just about every elite male runner (guys capable of sub 13:20) are running the majority of their miles at this pace.
Are they getting it wrong, and are all the much slower runners getting it right?
I know it's trendy now, but elites tend to do a very small amount of running in "zone 2". If we follow the definition of zone 2 being an intensity just below LT1, then for a 13 minute 5k guy, zone 2 is likely 3:10 - 3:40/km (5:05 - 5:55/mile). Very, very few elites are running anywhere close to this unless it's part of a workout (Graham Blanks might be the only one, but he doesn't upload all of his runs to Strava, so we don't see all of his actual easy days).
Zone 2 isn't the intensity just below LT1. We can't directly compare because Zone 2 is a heart rate zone and LT1 is not a heart rate measurement. But we can look at the %maxHR that most people are around when doing LT1 and see that there's a big gap between LT1 and the upper bound of Zone 2.
For example, for me personally (and these are just estimates, not lab results), my HR is low 160's for LT1. The upper bound of Zone 2 (for me) is mid 130's and lower bound is upper 110's. I typically do my easy runs with HR 120-130. If I'm really fresh and fully recovered, I'm going 7:45 pace, but the day after a killer workout might be 9:00. My LT1 pace for a continuous effort is around 6:00. So there's a massive gap. The only time I run those in-between paces (meaning mid to upper 6's, low 7's) is in the first third of a progression long run.
This gap between LT1 and Zone 2 is widely considered a "no man's land" pace. In other words, if you're running your easy miles faster than Zone 2 but not hitting LT1, you're wasting effort. You ought to be slowing down your easy miles to Zone 2 for the same benefit and less fatigue and wear and tear.
So Zone 2 is the next useful intensity below LT1. But they're not close in pace.
Having said all that, you do hear of world class distance runners jogging 8-10min miles sometimes, and those must be in Zone 1 for them. But the majority of their easy miles that slowly? I don't believe it. Maybe there's someone but that's not the norm. There are some Zone 1 fanatics out there in other sports but it's not a trend that has taken over the training of world class track and road athletes.
The problem is the zone 2 proliferated by Inigo San Milan (Pogacar's one time coach) is not the same zone 2 that others are referring to as an easy intensity; one in which you can recover between hard workouts.
By Zone 2, San Milan is referring to "Fatmax", the point of maximum fat oxidation. He sees this as the best intensity for mitochondrial activity. This intensity is just below LT1 (very, very close to being at LT1). So they are actually very close in pace, it's just that we have this weird distortion, where some people call zone 2 "60-70% max heart rate" intensity, and San Milan calls it this moderate intensity just below threshold - and so people have come to think of it as existing somewhere in the middle (a kind of "steady pace").
The whole thing is nonsense, and we should just pay attention to what the best runners are doing, not base our training off the intensities practiced by athletes in a low-impact sport like cycling.
Some have said that LT1 = a lactate value of 2.0mmol, but according to Mads this is absolutely not true. I've heard that whatever your resting lactate value is, once you have completed an LT1 session...your lactate value, should be about the same as your resting lactate value - so around 0.8-1.2mmol.