The Perfect Long-Run Distance for Best Marathon Results 

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The reason that some of us get so anxious about limiting the long run to 20 miles is that that distance is well short of the dreaded wall and there is a sense for which we want to train to overcome the wall. There's at least three physiological factors that would motivate longer long runs. The most obvious is durability and the sense that if we don't train the musculoskeletal system to go that distance we risk injury during the actual race. I suspect that the majority of the effect that people see when they see that the number of 20 milers that they run in a training block is predictive, is that people who run frequent 20 milers in their training block are likely to either not run the race because they injured themselves in training or to have such good durability that they are comparatively unlikely to injure themselves and have to walk. You rightly point out that the durability factor can be gotten around by doing things like pre-fatiguing. Camille Herron claims that she never does a long run during training and she is actually doing academic research on durability. Instead she goes for things like medium-long doubles, where she might run two 15-milers in a day. (She is an ultramarathoner so I wouldn't necessarily translate that into what a marathoner should do.) The second factor is energy usage and the idea that we will bonk at mile 22 unless we are prepared for it by training at least that long. The thing with this is that the way to address it is mostly through proper fueling, in other words getting the taper and carb-loading right and practicing being able to consume the proper amount of calories during the race. None of this is helped necessarily by doing a long run past 20 miles. The third factor though is one that I'm not convinced we should ignore, and that is muscle fiber recruitment. In fatiguing the muscles we gradually use up all of energy stores in our slow twitch muscle and start recruiting the fast twitch muscles to do the work. If we aren't running to a point where the muscle fatigue has recruited most of the muscles in use by the end of the run, some of those muscle fibers won't be getting that adaptations that will enable performance past the point where fast twitch muscles are being recruited. It may be possible to get to this point by simply running faster over the course of a medium run but there isn't great research showing this so far as I have been able to find. A possible last factor is the psychology. Especially for someone who has never run a marathon before it can seem like you just want to get confident knowing that you can finish the race without dying. A long long run can do that. It also seems to me to be important to distinguish between an LSD run and a regular marathon training long run. If someone who is normally an ultrarunner wants to go out and run very easy in the mountains for six hours, this is a very different thing than doing a 3 hour run at close to marathon pace on the roads and is far less likely to cause injury in those who are used to such training. I think there should be a lot of scope for doing a 50k super slow run in the base building phase before an actual training block if only for the psychology of knowing that the distance isn't going to be what kills you. Ultimately, while I think your conclusions and evidence are reasonably sound, it remains the case that the optimum long run is going to be dependent on the individual runner. There will be many out there who don't even need more than 15 miles in the course of their training blocks and many for whom a very long 24 miler would be beneficial. I personally haven't figured out where I fit in that whole spectrum.

I don’t do a long slow run of 18-20 miles. I do 15-16 miles: 4 miles @ easy effort, 6 miles @ marathon effort, and 4 miles @ 13.1 effort then 2 miles at 15k effort. The recovery is much faster too. You can usually accomplish a 15-16 mile long run around 2.5 hrs. A long slow run can program your body to have bad biomechanics. You’ll increase ground contact time thus increasing impact on joints. This type of long run is more time efficient. It upgrades your running economy, velocity at lactate threshold, fatigue resistance and aerobic capacity and power are all reinforced. Sometimes I’d go a bit faster: 5 miles @ marathon effort, 5 miles @ 13.1 effort, 3 miles @ 15k effort, and 3 x 1 mile @ 10k effort. I do long runs every 14-21 days. What I do weekly is a 20-20-20. 10 minute easy warm-up then the main runs: 20 minutes at 26.2 effort then 20 minutes at 13.1 effort then 20 minutes at 15k effort. 10 minutes easy running cooldown. I finally cracked under 4 hrs. doing this type of training. It teaches your body to become strong at holding speed for a longer period of time rather just a long slow run.

Thanks for including me!

Wow, Brodie! This is fantastic and will be so helpful for runners to truly understand why coaches say what they do. I think more videos like this would be super helpful for runners, keep it up!!

As a slower runner (2h20 half, 5+ mara), I like the 3-3.5hr limit for the long run. That would translate to around 14-16 miles at fairly easy/relaxed effort.

Another great video Brodie. Thanks for including me as one of your experts, it's an honor to be in the presence of so many great running minds! Keep up the great work!

Amazing video clear to the point great info to have

Love the references to academic research to back up your recommendations! Thanks Brodie 5:54

Wow what a great video, and a great idea to collate some truly expert opinions… plus I fall pretty perfectly into your target running group there too!! It’s wonderfully reassuring actually as it’s kinda what I’d pieced together from being a dedicated run smarter scholar!!😆😁 I think you know us so well Brodie ‘cause the temptation to do more is always there, a lot of your advice seems to be aimed at calming us down from overdoing it, and clearly run smarter rather than more!! I’m gonna do my first ever trail marathon in September, with over 1200m altitude gain, and must say I’m kinda quaking in my boots again! AND hoping to do my first trail 50k ultra in November!! 😬😬 I’ve been sorely tempted to go out and run a marathon in the next day or 2 just to practice suffering 😂😂 Hope all is well with the fam … are you back into running much yourself yet or too many sleepless nights for that??? Sending best wishes from hot sunny Paris!!

Great video, always look forward to new videos from yourself Brodie, so well researched, easy to follow and very informative. From my perspective I have completed 4 marathons now and have hit the wall each time. Initially I assumed it was due to nutrition, but I feel I have this sorted now (gels and water every 5km etc), but looking back over my training I lay blame on not enough consistent long runs. I may hit a 30k - 32k 2 or 3 times during the training block, but I have too many weeks where I don't run beyond 10k. That will be my plan when I get back into another marathon training block likely next, am in ultra mode at the moment having finished a 50k on Saturday and now working up to a 50miler in November 🥵

I finished my first marathon in 3:48. My longest run before it was 16 miles, followed the next day by 13 miles. That same week was my peak at 55 miles, which requires some fast running to get up to that. I had recently run a half at 1:45. The deciding factor on the time was really more about planning for a negative split (which takes faith) and fueling/hydrating properly end-to-end. I suspect that if I ever end up running 20 miles in a single run on the road, it will be because I've just naturally gotten faster. Running more than 3 hours in training isn't a great idea (ie adaptations don't come from one run).

The best explanation

Great video, Brodie! This is very relevant as I prepare for Chicago marathon. I feel that the fast finish long run, while definitely challenging, teaches you to push through on tired legs (especially if the prior week included speed workouts).

Hey Brodie, I need some advice on my last 6 weeks. I'm shooting for a 3:30 marathon time and have been following the Runners world sub 3:30 marathon training plan. I also use Garmin's and the Boston marathon plans to help keep me honest. I'm 53, stay very active with MTB riding, zwifting, surfing etc. but the 12 months prior to using this 18 week program were extremely light in the running dept. I'm almost 100% a trail runner and my average monthly mileage could range from 12 miles (dead of winter) to 40 ish miles with all the other activities sprinkled in there. My last 6 long runs are as follows: 15.5, 16.5, 18, 20, (15 - 1 mile warm-13 @ 7:58 - 1 cool down) 18.5 with the last 4 @ 8min - My average weekly mileage is around 40(highest 48). With 6 weeks to go, what do you think my next 4 long runs should look like? I am injury free but definitely have my share of aches and pains. I feel like my plan may have me over doing it? Thanks in advance!

This was very helpful! Thank you

Thank you for the clearly demonstrated tips and summaries from multiple sources!

Great video, very informative, thank you!

I must say that for me, a distance I haven't covered in training is a distance I won't be able to cover in a race. My longest long runs before my marathon (first one, for now) reached 37.5 km, and what do you know, I held up fine, very close to my target pace, up to about 37 km in and then hit the wall hard at about 38 km into the marathon, to the point of needing medical assistance after the race (and, needless to say, coming almost 15 min. behind that 4 hour target time). In training, on the other hand, I was able to complete 36 km or more every week in my last two training blocks before taper without injury (lots of strength training...), reaching 140 km in total in the last week without any issues. Still, a distance not covered in a few long runs is a distance I don't have the stamina to cover in a race.

very helpful and solid content 👍

any insights on optimal long run distance for the half marathon? i've been focusing on the half this year and going for my final shot of 2023 in a few months. i've been holding at 16 miles (which takes about 2 hours for me) because i've found it's the sweet spot for a quick recovery while still being challenging at the end. there's not as much research/emphasis on half marathon training, even in hansons, daniels etc - would love to see some more half specific content

My target is 3hrs marathon. And I had a couple of 3hrs long run at +30s pace, which covers 24~25 miles. And I feel they are the best for the preparation. I got a taste what 3hrs mean, as well as what it feel beyond 20 miles. The recovery is never an issue, due to slower pace.

My goal marathon time is sub3h, my easy pace is ~5'45"/km, and my 5k pace is 3'32"/km. At my easy pace a 20 mile run would take me 3h5', even longer than my goal race time. I like the idea of incorporating race pace miles in the long run. Would you suggest limiting the long run to some duration? For example 14 miles at easy pace + 4 miles at race pace would result in 18 miles in 2h37'. Thank you so much, what a discovery your channel has been right at the beginning of my marathon training!

My best friend did his first marathon in 3:47 with the longest run before of 23km only, he did have many 21k's before but that's about it, I was shocked how he didn't need any long runs but I get it. After 20km, my form at least tends to break down, can't even imagine how much it does break down after 30km. Maybe the length itself is not as important as what you did the night before the long run, how well you slept, ate, levels of muscle soreness and so on. Doing a moderate run 1 day before and shortening the long run makes the most sense to me, will try that one out once I'm at 3hrs time for the long run. What I wonder about is what kind of HR/RPE these long runs should be? Elites seem to do insane long runs, where they are pushing very hard, close to goal pace (20seconds/km slower at most) but that seems impossible for a regular joe like me, couldn't recover from that for days and most likely get injured. For now I'm going as slow as possible to not reach lactate threshold HR.

Great video thanks. Is it proportionate for half marathon?

This 20-22mi long run limit has been around for many years. Should this be updated now that we better understand nutrition and use super shoes that means we feel better at the end of the run and take less time to recover.

why could ultra runners run 5hrs during training but marathoners are advised not to go beyond 3.5hrs? is it because ulta runners run their long runs slower? then run your long runs slower

the logic for no necessity for full length training explained: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-VQLU7gpk_X8.htmlsi=vaqnMQIk0OxCOt5Y

15 miles

20 miles is a terrible idea. Especially for a 4 HR runner

James Dunne is a big hulking fellow I'm afraid whatever advice he can offer wouldn't apply to anyone with a normal sized body.

please do not throw around the word evidence based. welcome for my comment.