Long runs - time or distance?

I am hoping that some experienced marathon runners can help me with the dilemma I have following my long run today. 

I am training for the Edinburgh Marathon at the end of May and am working on increasing my long run distance before I start a schedule at the end of January.  It will be my first marathon and I am hoping to finish in around 3:35-3:45 (based on my 10k and half marathon time).  Today I did 16 miles in 2:15 and I was really pleased until I realised that I had been told two things about long runs: 1) do 20 milers 2) run for the same amount of time you expect to run in the race.  Having done that distance today I have realised that it is not going to take me 1:20 to run an extra 4 miles!  So I am confused.  Do I do the 20 milers and run for less time than I expect to complete the marathon in or do I run much much slower and do the time? 

Thank you!

Hi. I personally dont believe in the "time on your feet" method of training because at the end of the day you have to run 26.2 miles whether thats in 2.10 or 6.30!!! The other thing is that LSR's dont just stop at 20M. To increase your chances of a good time you can do runs of up to 23M. I would recommend going beyond that.

 although its horses for courses, LSR's are meant to be done between 30 -90 secs slower than race pace. Although some people say "how can you run at that pace if you haven't trained at that pace?"

so my recommendation would be to do the LSR's in miles and not time, if you can do 21M, 22M and 23M LSR's then do them.

Having now run 3 marathons with a PB of 3:11 I recommend running at least 5x 20 mile runs before. This gives you enough time on your feet and builds up the stamina, with a good taper you will toe the line feeling great. But don't get carried away as the halfway point is 20+ miles. I had only done 1 LSR for my first marathon and paid by hitting the wall, more 20's is the key.

Hope this helps a little

I've got to agree with paul a, 16 miles isn't long enough, it's only just over half way. You'll still probably get round but you're going to find the last 5-6 miles hard.

For my last marathon (pb 2:55:55) I did a mix of "time on my feet" and "marathon pace" long runs, loosely following a Frank Horwill schedule

So what physiological benefits will a 22 mile run and a 10 mile run give you over two 16 mile runs ?   

If the argument is you have to replicate the race then would you also run your long runs at marathon pace - and if you were training for 50 mile ultra would you recommend 40 mile training runs ?  

Yes miles are important - but to an extent you can split them up to reduce chance of injury and muscle damage.    For runners who have years of high mileage in their legs then several 20 mile plus runs are sustainable - but for people who don't have that history I think they are counter productive and unless you are on a very high mileage schedule and need to do the very long runs to hit target mileage you'd be better off on 16 milers as your long run.  

Having now run 3 marathons with a PB of 3:11 I recommend running at least 5x 20 mile runs before. This gives you enough time on your feet and builds up the stamina, with a good taper you will toe the line feeling great. But don't get carried away as the halfway point is 20+ miles. I had only done 1 LSR for my first marathon and paid by hitting the wall, more 20's is the key.

Hope this helps a little.."

I have now run seven marathons and have to agree with No pain's advice totally. I would also throw in a run/walk of your expected finishing time to aid the 'time on feet' .  By doing several 20 milers you will feel great benefit and see distances in the low teens as having a day off.

All the best. 

But what are the physiological benefits that occur between 16-20 miles that aren't happening once you've been running for an hour - if there aren't any then why take the increased risk of injury and muscle damage ?   

paul a wrote (see)

. There is no substitute for LRs in marathon training and no shortcuts.

No shortcuts, certainly, but there are substitutes for long runs. A high weekly mileage will give most if not all of the physiological benefits that long runs provide. There was a discussion about this in the early stages of Mike Gratton's hard training thread - he said that in his experience the long runs become less important as weekly mileage increases. He referred to one marathon programme that had no runs above 13m, with a sustained weekly mileage of 80+.

The thing that bothers me about a lot of marathon programmes is the proportion of mileage that is taken up by the long run. Some will have long runs of 20m or more while the weekly mileage is no more than about 40m - in other words, around 50% of the weekly mileage is being done in a single run. It's no wonder that many of these runners talk about needing several days to recover fully from the long run. In some of these programmes, I'd argue that the long run itself is being used as a shortcut, in an attempt to make up for the lack of sustained mileage elsewhere in the programme and in the runner's background.

I don't think a long run should ever represent much more than about a 1/3rd of your weekly training volume. Marathon training can represent a bit of an exception to this... but still.. if you're doing a 40-mile-week and you do a 20 mile LR.. that's half your mileage?? I just can't see the logic behind this personally. 

 I think realistically this comes down a lot to how fast you are, how much training you can manage and what time you're going for. Dan Robinson did 140mpw in the buildup to Beijing, so even doing a LR of 30 miles wouldn't be touching a 1/4 of his weekly mileage. It's all relative... to the training... to the person and to the aim. 

A marathon is not a marathon. I made this mistake trying to step up from 10k to Half-Mara. It kicked my arse... and I was off running for several weeks. 

And as Pammie said, it's about building yourself up... not knocking yourself down. If the long runs become so long that you can't recover from them... then that's counter-prodcutive. 

Aardvark is right too about overall mileage.