Why Limit the Long Run to 20%?

That rule is a bunch of BS. It should be based off of time and some runners should do very long run. Think of Kenny Moore not doing well in the marathon until he started doing 30 mile long runs.

Jaxrunnr wrote:

I keep reading a common training rule that the long run should be no more than 20% of the weekly mileage ... Is there a specific reason for this? High risk of injury, some other physiological reason?

That's a good question. As a low-mileage runner, my long runs are typically 40% of my weekly total (18- to 20-mile long runs, 40 to 50 mpw). The long runs, I believe, shouldn't be compromised in marathon training, even with low overall mileage.

That approach netted 2:40 as a youth, and 3:07 at age 58. I've also trained at super-low mileage, where the longest run each week has been 75% of total mileage (3:25 marathon at age 57).

It is a rule of thumb and that is all it should be viewed as. For example, if you only run 5 days a week, every day would have to be the exact same distance not to break that rule, and that doesn't really work.

I tend to use 25% as my upper guideline rather than 20%. I also disregard it altogether with respect to marathon training.

But yes, the underlying reasoning for the rule of thumb is that it creates a reasonable range of tolerance without materially increasing the risk of injury.

I see a danger when the length or importance of a weekly long run becomes too big a part of the training plan. I see this when it compromises the rest of the training plan. I see some plans limiting training before and/or after the long run, reducing VO2 work a few days prior, and other concessions just for the long run. Over time some plans end up having a long run and one other quality workout per week. This may be fine for some but not the optimal plan in my eyes.

It depends on your weekly mileage. My long run is usually between 15-18 miles regardless of my current mileage. So when I am in peak training my weekly long run is only like 13%-18% of my weekly mileage. But when my mileage is lower it is around 20% -25% of my weekly mileage. But to say 20-25 % of weekly mileage is silly since the long run is based off of time and if someone is running 150+ miles a week there long would be 30+ miles and someone running low mileage let's say less than 60 miles a week is technically basically doing a long run every time they run according to this rule. For example, if someone is only running 25 miles a week, is a 5 mile run really a long run? No, obviously it is not.

I usually see 20-30% is used and I generally think it is good info to have as someone who is a novice is likely to run far too fast for their runs including the long run. From what I've seen with such individuals the vast majority of injuries occur because of this reason. Not that they'd really listen to or respect someones info and stick to it anyway. For example such a person would be possibly someone running between 1:50-2 hours for a half marathon yet they run the majority of the time around 8:30 pace or faster. Or maybe they want to run 1:45 for a half so they think running every long run near 8 minute pace is a smart idea. Your average person new to running will think "Oh I think I can run 8s for a half so it's no issue for me to run 5-6 miles at sub 8 for pretty much every other run. It's ridiculous. I try to coax them out by asking how they felt but 9/10 they continue to lie to themselves. How could someone not be able to run sub 1:50 yet say that a 5 mile run significantly faster than that doesn't tax even their lungs?

that is a bunch of bullsh%t wrote:

That rule is a bunch of BS. It should be based off of time and some runners should do very long run. Think of Kenny Moore not doing well in the marathon until he started doing 30 mile long runs.

As I recall, the prescription for the LR was between 20% and 25% of weekly mileage. I don't know that much about Moore's training off the top of my head, but I wouldn't be surprised if he was running 120 mpw. His 30 mile LR would fit in the 25% window.

I'd also like to echo what others have said about low overall volume and people running 3-4 days a week.

If training for a marathon on relatively low volume, you can throw that 20-25% rule out the window. But, if you're looking to be an overall well developed runner (Mile - Half Marathon), then the total volume is far more important than a long run.

CoachB wrote:

that is a bunch of bullsh%t wrote:

That rule is a bunch of BS. It should be based off of time and some runners should do very long run. Think of Kenny Moore not doing well in the marathon until he started doing 30 mile long runs.

As I recall, the prescription for the LR was between 20% and 25% of weekly mileage. I don't know that much about Moore's training off the top of my head, but I wouldn't be surprised if he was running 120 mpw. His 30 mile LR would fit in the 25% window.

He was actually not that high of mileage. I don't think he went over hundred miles a week that often. He did train in a 9-10 day block too.

obviously it depends wrote:

It depends on your weekly mileage. My long run is usually between 15-18 miles regardless of my current mileage. So when I am in peak training my weekly long run is only like 13%-18% of my weekly mileage. But when my mileage is lower it is around 20% -25% of my weekly mileage. But to say 20-25 % of weekly mileage is silly since the long run is based off of time and if someone is running 150+ miles a week there long would be 30+ miles and someone running low mileage let's say less than 60 miles a week is technically basically doing a long run every time they run according to this rule. For example, if someone is only running 25 miles a week, is a 5 mile run really a long run? No, obviously it is not.

Who is running 150 plus miles/week??

kmaclam wrote:

obviously it depends wrote:

It depends on your weekly mileage. My long run is usually between 15-18 miles regardless of my current mileage. So when I am in peak training my weekly long run is only like 13%-18% of my weekly mileage. But when my mileage is lower it is around 20% -25% of my weekly mileage. But to say 20-25 % of weekly mileage is silly since the long run is based off of time and if someone is running 150+ miles a week there long would be 30+ miles and someone running low mileage let's say less than 60 miles a week is technically basically doing a long run every time they run according to this rule. For example, if someone is only running 25 miles a week, is a 5 mile run really a long run? No, obviously it is not.

Who is running 150 plus miles/week??

Bill Rodgers in his prime regularly ran that much. Looking through his training log I don't recall that many runs being 30 mile long runs.

If you want a longer long run just run more the rest of the week to keep the 20%.

If you’re putting in 100 miles, 20 miles is enough.

If you’re putting in 50 miles, 10 is enough for your long run.

If you run less than that, it’s not full time training, so the ratio could be different then.

Um no. It really depends on the race you're targeting. If you're running 50 mpw to prepare for a 5K, then a long run of 10 miles might be fine. For a HM, it's not fine at all.

1970s training wrote:

kmaclam wrote:

Who is running 150 plus miles/week??

Bill Rodgers in his prime regularly ran that much. Looking through his training log I don't recall that many runs being 30 mile long runs.

Regularly? Are you sure you don't mean "occasionally"?

Load of BS, make your own rules while training but only do what your body lets you. My long run is more like 33% .

I run 25 mpw (I’m have no desire to increase miles, I run for oure enjoyment and fitness) so I accept my slower times. I prefer to just get a 30 minute run in a day and then ever sunday night I run for 90 minutes and it is always the most therapeutic run of the week. Going by the 20% rule I would only be running for 55-65 minutes on my long run but I find the most thereputic feelings come in the 60-90 minute mark.

If you are running 25mpw you are not qaulified to give advice on a long run.

I see the problem wrote:

If you are running 25mpw you are not qaulified to give advice on a long run.

I agree with this. You can get away with running a higher percentage bc you hardly run at all.

This subject came up in another thread and I put this in response:

The 20% business makes sense for a certain range of mileage. If you're doing 70-100 miles a week a long run of 14-20 miles can work well. But when I was doing 140-150 mile weeks I'd have needed to do 28-30 mile long runs just because some formula told me to? If anything, because I was doing all those miles I think I'd need long runs LESS than if I'd done fewer miles. I have a friend who did 2:13 with no runs longer than 8 miles but with 120-130 miles a week. On the other hand, when I was doing 50-60 mile weeks and running marathons, I don't think a 10-12 long run would have been enough.

malmo wrote:

1970s training wrote:

Bill Rodgers in his prime regularly ran that much. Looking through his training log I don't recall that many runs being 30 mile long runs.

Regularly? Are you sure you don't mean "occasionally"?

....and you are citing one runner from 40 years ago. That was my point!