... ... The long run - how long is long enough? - Mile27
Mar 182013

Photo by Stefica Key

Photo by Stefica Key

The long run is obviously the most important training session of the week for an ultra runner but how long should it be?

I was initially of the opinion that longer was better but after building up to a long run of 75km before my first ultra and dying big time in the race I re-evaluated my ideas.

For my second race my longest run was only 45k and it was run at a much slower pace than my previous long runs. This was a resounding success as I was still running strong with 95 miles of running in my legs.

Why the big difference and why did running less ks at a slower speed in long training runs result in me running more ks at a faster speed during the race?

Whilst you may read about some of the pro’s putting in 8 hour training days on a regular basis the majority of us haven’t got the time to do this or the bodies that could handle that kind of training so we need to be a bit smarter about how we go about it. The often quoted rule when training for marathon is if you can do 30-35k in training then you can do 42k come race day. Using the same percentages for an ultra would have you running 70+k run for a 100k race or a 120k+ for a 100mile race. Clearly not a realistic goal.

So what is the ideal distance?

Unfortunately there is no best answer for this as it depends on a number of variables including the amount of ascent descent covered in the run, the speed you run at, the terrain you run on, what your body can handle, the recovery time necessary after a long run and the amount of training you have done for the rest of the week. Manipulating these variables to discover the optimum long run distance for you is more art than science but there are several guidelines you can apply.

1. Recovery Time

The longer the run the more recovery time you’ll need. There is a point of diminishing returns where the longer your run the more days recovery you will need. This obviously impacts training for that week. If you need any more than a days rest before you can run again then I feel your long run is too long (or you are running it too fast)

2. Intensity

A common mistake for runners making the jump from marathons to ultras is to continue to run their long runs at the same pace. This is fine if you are training for a 50k but if you are training for 100k or more then you need to slow down. Your long run should feel easier than the long runs you did training for a marathon. Running your long run faster is not necessarily better. The aim of the long run is to build endurance by improving the bodies ability to burn fat, increase capillary density and mitochondria in the muscles. The faster you run the less fat you burn so the less stimulus there is to improve your fat burning ability. the faster you run the more damage you will do to your muscles which can affect the rest of the weeks training.

3. Terrain

Your long run should be done on similar terrain to your race. You can’t expect to cope with running 100k with 5000m of ascent descent if your long runs are 40k and covering 500 m elevation change. A good aim is to work at increasing the elevation change per km to the same as expected in the race. Ie if the race has 5000m in 100k then that’s 500m per 10k. You should aim to gradually increase the elevation change so that you get to approx 1500-2000m for 30-40km.

You can also use this principle based on time rather than distance. Ie If you are hoping to run 100k with 5000m of elevation change in 20 hours then that’s 250 metres per hour so a 4 hour run should have at least 1000m of ascent descent.

If your race is on technical trails then it makes sense that your long run isnt done on road or gentle fire tracks and vice versa – train specifically for the course.



Photo by Stefica Key

5. Back to back or single long run?

Running back to back suits many runners better than a single long run. Covering 50-70km in 24 hours is a lot less stressful on the body than covering the same distance in 12 hours. So for example running 25-35k on Friday afternoon followed by 25-35k Saturday morning would place less stress on the body than running 50-70k non stop on Saturday.

The one proviso for this is that you don’t run any harder just because you are doing only 25-35 compared to 60. When you set out Friday afternoon tell yourself you are running 60k and adjust your pace accordingly. When you stop after 25-30k you should feel comfortable and not be exhausted.

Another way to use back to backs is to do a shorter but higher intensity run the day before the long run to get you used to running long on already fatigued legs.

6. Walking in your Long Run

Too many runners think that walking is a sign of weakness , after all if you are a runner isn’t walking cheating? However in an ultra – particularly a trail ultra almost everyone walks some of it. So you may as week practise it. Walking in your long run also allows you to cover more mileage with less risk of injury . For example running 40km non stop will put a lot more load on your legs compared to running 50k but broken up into a 5k run 1k walk. For more info on how to improving your walking during an ultra have a look here

7. The really long run

Once or twice before your main race I think it’s worth spending a weekend getting one or two long days on your feet. Before all the successful 100milers I have done I have spent a weekend around 4-5 weeks before the race covering 120-160km in a period of 2-3 days. As I compete in trail races this is all done in trails and includes a fair bit of walking. I have found that although I generally need 2-3 days off after this the benefits gained outweigh the lost days training. The pace for these should be very very easy and the goal is more to spend 8+ hours on your feet for a couple of days rather than trying to run a certain pace. It’s also a great chance to test out your nutrition strategy and race gear. Depending on what your weekly mileage is and how long your long run is will govern how much you run and how much you walk.

8. Injury Prevention

Always remember the more you run in a fatigued state the more susceptible to injuries you will be. The length of your run should always be moderated by what your body can handle and what it can recover from. Keep in mind that some injuries such as tendon injuries are cumulative so whilst you may feel ok after one long run, a month later you are in pain. Progress slowly and always err on the side of caution.

So why did a much shorter run at a slower pace give me far greater training benefit than a longer run?

That 45k run was run over 6 hours and included well over 2500m of ascent and descent. It was preceded by a 30k run the night before which also included nothing but hill reps. I recovered well enough from this to hit the track two days later and clock up some respectable 1 mile repeats (sub 5.30). Previously the long run built up to a point that I would need at least 3 days to recover from. Being able to back up from long runs and run at speed a few days later made a massive difference to my endurance at the back end of a 100 mile race.

Thats not to say this is the best option for you. This worked for me when I was training for UTMB with the massive amount of ascent and descent but for less hilly 100 mile races I have trained differently.

By considering all the variables and listening to your body you should be able to find the optimal distance for your long run.

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  27 Responses to “The long run – how long is long enough?”

  1. Great article Andy. Nice work!

  2. Excellent post. I am not an ultra runner, I just run for fun since about one year, still trying to find out what suits me mostly in this field, but I find these information very helpful for me too, thanks.

  3. Hi Andy

    Thanks for the excellent article. I am in training for the Northface 100 so the timing of the article was great for my motivation.

    I think after reading it, my approach to the long run is flawed. I basically have been using a mini taper of 3 days before my long run. This means I am not really getting my body prepared for running in a fatigued state I guess. I suspect my long run is also not long enough and is run too quickly going by what you have wrote.
    Look forward to trying something new this weekend,


    • Thanks for your comments Ian. Mini tapering for your long run and running it too fast doesn’t really prepare you for running slow when fatigued – as will happen in the second half of TNF. Doing your long run in a fatigued state from the rest of the weeks training will teach your body to run in a fatigued state. You just have to be mindful that running in a fatigued state may increase the risk of injury so important to listen to the body

  4. I was just preparing my plan to step up my long runs but was asking exactly the question – this has really helped. Thank you.

  5. Really good tips.

  6. Thanks Andy,im preparing for a 100k trail run for north face thailand in feb 2014,your tips are really helpful. I was doing the runs faster and struggling to go more than 25 km,let me try a slower pace as per your advice.thanks,for a 100km trail run im considering using perpeteum and endurolytes only,is this sufficient?appreciate if you can give some tips on nutritional strategy for a 100 km trail run.thanks in advance for all the useful tips and sharing !

    • Hi Tejo

      Perp and endurolytes is definitely sufficient – I’ve used the same for a number of 100mile races including UTMB and felt great – as long as you know how much you should be having per hour and stick with it , you shold have a nice stable energy levels for the whole race. But some peoples stomachs do get sick of it after a while and like some variety so try it out in training

      Good luck with your preparation


  7. Great article Andy. I agree with all your principles

  8. Fantastic article Andy, so many great tips, thanks for sharing

  9. I saw this in a post on a ultra training group FB page I am a member and glad of the read. This mirrors exactly my preparations for a K78 event I am doing this weekend. What I also found is running at slower pace (inc walks) has really protected me from injury but also I posted a 11min PB in a marathon event 7 weeks ago – testament to my new found endurance was the ability to complete a 2min -ve split in that event. I know have a faster average pace for 42.2km than my old 10km mark.

    I totally agree with your article, thanks for sharing, gives me added confidence my preparation of this weekend was ideal.

  10. Great advice that is so welcomed and so superbly written

  11. Hi Andy,

    I initially read this some months back, but was too far into my training to alter it. I was into long back/back runs, training on tired legs mind set, with little no short hi intensity sessions- although i did do circuit training & yoga for strength and conditioning. I also cycle. I was all good to go for my first 100km last week end – a very tough coastal path in Cornwall, S.W. England.

    It went wrong. Very horribly wrong. I barely made it to the half way point, but was encouraged to make it to the half way and a little bit beyond. I covered 36 miles.

    I am now completely re-evaluating my training and have re-read this article. My long runs were too long; there was little -to-no short , intense runs; my long runs were too fast; i had too few rest days.

    I now want to get this right and will be devising new training based on this article, as it makes more sense now!

    Thank you,


    • Hi Murray – thanks for the feedback, I hope the article helps turn around a disappointing performance into a great result in your next race !

  12. I am a Marathoner since 2012 and I ran two marathons per year so far and looking forward to do a 100K race in April 2016 as my first ultra. This your article gives me some very useful and much needed information. Thank you very much! I will run my next marathon the coming week in Berlin, and afterwards I will start looking for a 100K-training plan for me. Do you have maybe any advice for me? I’d be very thankful for every tips and recommendations. Thank you!

    • Good luck with the marathon Zegi. 100k is a lot different to the marathon – back to back runs are great for 100k training – a hard tempo run one day followed by long run next day on tired legs.


  13. Really good article. At the moment I’m training for the Comrades and following the official program. (Back to back runs)
    I had a sudden panic attack that I wasn’t doing enough really long runs, like the rest of our running group training for Comrades were doing; but rather back to back training like you have described. Your article has given me confidence!

    • Hi Mary

      Thanks for your comment – great to hear its given you some confidence. Many people worry that there long run isnt long enough but back to backs are for many a great way to buold that long endurance without needing to do mega long runs. Best of luck with Comrades

  14. Andy, you wrote this in 2013, and it is as relevant today as it was then. Most advice on running comes from elite runners on the rationale that to be elite they must know what they are doing. I agree, but most of the readers of that advice are not elite, many are a lot older, many have a history of injuries, and others are inexperienced. Your article is refreshing because it is applicable to all runners. In my case, I am an older runner with permanent mild disability in both knees following extreme surgical procedures, and a high demand on my time from family and work. I am sure I’m not alone. I’ve found ways to adapt, and still run long trails. There is no way I can follow most training programs – my volume has to be significantly lower than recommended or I’d break down. I try to make up for my disadvantages with cross-training (I swim and cycle), some high intensity and hill work, strength work, consistency (train no matter what’s going on), and impeccable preparation for and execution of the race itself. Your advice has given me some new ideas to add to that, so thanks.

    • Hi Chris

      Thanks for commenting , glad you found the article helpful. Totally agree that consistency and good preparation and execution of the race is so important – finding what your body best responds to , how much it can handle without breaking down and how to fit all that in the time you have available is the challenge of training! But its the key to minimising injuries , maximising performance and maintaining enjoyment for the sport

      All the best


  15. Hi any like ur article on back to back long runs sumting new for me finding out abt this kind of long runs I’m in my early fifties did abt 2 ultra marathons the question are how often in a 27week program can I do a back to back run will prepare for 2018 two ocean ultra marathon

    • HOw often you can do them depends on a lot of variables – they are more stressful so you need to have good conditioning in the legs to do them. Some people can handler them every weekend – others only once or twice in the lead up to a race. Build slowly and allow your body to adjust before attempting a long run double.

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