The 20 Mile Principle: Do Runners Need Them?

Sport Scientist Lindsey Parry has coached thousands of marathon runners from 'back of the packers' through to Olympic marathon runners and in today's video he explains the 20 Mile Principle for marathon runners.

We'd love to know how many 20 mile or longer runs you do in the build-up to a marathon? Please let us know in the comments below...

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When you're ready, we'd love to help you become a better runner:

In this video:
00:00 Should you be running 20-mile training runs
00:18 Where did the 20-mile rule come from?
01:33 Is a 20-mile training run necessary?
02:13 Who should be doing them?
02:44 The psychological benefit of a 20-miler
03:43 What's the point of a 20-miler
05:14 Where does the 20-miler fit into your training

#CoachParry #Marathon #Running #RunningTraining

[paulwestendorf]

18 to 19 miles has been my Long Runs this last year. PRed early in the year and then again in November at Monumental. I agree with your philosophy/strategy on what to accomplish during the run.

[ruudwelp]

I did a 35km run 3 weeks before my first marathon last November, and felt it as a huge confidence booster. It was exhausting but I felt so great and proud afterwards that I knew I would be ready for the marathon.

[RamblinView]

I ran my first marathon last November in 2:53 with my longest run being 16 miles beforehand. I averaged higher daily mileage consistently instead of focusing on one long run to make a majority of my week. Worked great — Hansen’s marathon project made this style of training popular

[mornafleming]

Psychologically, I prefer to know that I have run at least 22 miles in training, as the unknown beyond 20 up to the finish of the marathon is what always catches me out.

[jonor]

Recovery is age dependent. Doing a 20 miler in race pace four weeks before your target run might keep you from recover properly, especially if you are 45 y/o or older. A 20 miler long run to build strength in your legs might be a good idea. Take your time at the water station by slowing down. Getting the right amount of fuel (water/sports drink) during the marathon is the key to success and can avoid you from hitting the wall. add gel as extra but do not replace it with fluid.

[nicolablignaut]

I’ve run 15 marathons which include a Comrades and 3 Two Oceans. I still don’t consider myself an experienced runner and feel so much safer doing one 20miler before race day. I’m a back of the pack, go for the social kind of runner but I still need it for my mental state. Great video! Thanks as always…

[neilgarrod]

I've always found that 'normal' 10k training always enabled me to race distances up to 30k. Anything longer and the the training runs had to be extended. I always found the build up to the 20 miler very helpful in this process

[dburriskitchen]

Love this! I know I always need the 20+ miler to remind me that physically and mentally I can still do it.

[jeffstock]

I ran marathon at age 21, at the time, I could do a 5k around 18 minutes. My longest run in my life before that was a half marathon (done exactly one week before, which I didn't find too difficult). I ended up running a 3:41 and I couldn't walk for a week after and stopped running for over a month because of soreness. So please train for your marathon. 20 miles seems very reasonable to me

[georgewoodward]

I agree, it depends. Instead of miles think time. The is a fair amount of science that tells us that running longer than 3 hours or a little more is counter productive. If your goal is to finish and your long run pace is 12 minute miles then NO 20 is too much. On the other end if your long run pace is 8 or 9 minutes then it may work for you. I do 16 as my long run, 3 of them, and then one 20 and it's most important part is for my head. I also finish the 20 with the last 4 at MP. I know if I hit that workout I am ready. (or at least my head thinks I am :>) )

[stefanlanger]

Thanks for the video. I’ve run more than 20 marathons so far (about 75% of these I consider a success) and I’ve never done a 20miler at race pace as part of my preparation. I consider it too hard an effort and to difficult to recover from properly. What I do sometimes is to run a half marathon race not at full speed but at marathon race pace in order to check if this pace feels good for 21k. The longest easy runs in my build-ups are about 18 miles (28/30k).

[irmaputtonen]

I have run seven marathons in my life. I have run a 30-35 km training run three to four weeks before the race day, but always considerably slower than the actual race, to ensure recovery before the race.

[melaniegulliver]

I’ve run three marathons now. The first one I did when I was 50 and with traditional build up of training and max training run I did was 30kms (should have been 33kms but I ran out of time) and I still wasn’t confident I would finish that first marathon until I got to the 36kms stage.. almost cried then!
For the second one I followed a plan saying no need to run more than a half in training but with more intensity. I really suffered in the last 6 miles on this one.
The third was just a few weeks after the second and I took it really slow and enjoyed it.
So I would always want a longer run if possible in my training..

[joshschoenick]

I’ve been building my peak weekly mileage for the last two years with three training blocks a year. I trained for 5k the first spring, 10k that summer and a 1/2 marathon that fall. I increases my peak week by 5 MPW each block. 40, 44, 50 year one then 55, 60 and 65 year two. I started at 20 miles and build up with a two week taper each block. This winter I did a recursive build (3 steps up, 1 back) over the last 12 weeks. I kept my long run at 20% of weekly mileage year one and 20-25% year two.

The aerobic capacity increase has enable me to go from 1:48 fall of 2020 in the 1/2 marathon to 1:32 last fall in 2021. Shooting for a 3:15 BQ time in May in my first marathon.


All this to say, I’m now at 65 MPW and have held it the last 3 of 4 week with one taper week for a 5 mile (8k) race 2 weeks ago. I built up to 16 miles before the race and felt great and strong. I took on an 18.5 10 days ago and a 20 miler this week and though the workouts went well, it did take a toll on my legs. Though the 20 miler honestly felt better this week at 25 seconds slower than race pace (race in 8 weeks). I have more more week planned to reach 70 MPW but I think I’ll drop my LR back to 17-18. It took two full days to recover and my legs still aren’t 100%. I also ran very hard in the 5 mile race that took 3-4 days to recover. But set PRs en-route in every Strava PR distance from 400m to 5 miles. I’m sort of regretting that final kick effort now.

[rrsp]

I always followed Hal Higden's training. But my fastest marathon was after I trained with 2 runs of 28 miles - this gave me the confidence to finish strong from miles 20 to 26 - especially was able to run all out the last mile.

[shannonbarras]

I've always topped out at 18 miles. Doing 2 or 3 of those. And I would consider myself an experienced marathoner. Not an age group winner, but a Boston marathon qualifier level.

[stevelafler]

Running a Nov 4 marathon here in 2023, and I parked an 18+ mile run 4 weeks out. Also did an 18+ run about 5.5 weeks out. These were preceded by gradually increasing series of long runs over the buildup, about every 9 days or so, alternating with tempo run workouts between long runs. Of course mostly easy days. I feel ready for a BQ (-10-15 min.), 3 weeks out I threw in a 10 mile run with a negative split. I'll taper for a couple weeks. Thanks for the great info, it resonates.

[kevindecoteau]

When training for Boston a few years ago, I did a twenty miler about 4 weeks before the marathon, it exhausted me, when race day came I still had not fully recovered. I recommend a 17 miler at the most.

[barefootbasics]

Back in the day I always thought I needed to run at least six 20 milers before taking on a marathon. These days I only run 3 to 4 days a week like many of my old running friends who have kept up running do. I've run 26 marathons (with a pb of 2:28) and do not see the need to run such long races anymore. Now in my mid 60's I like to encourage people to get off the couch to least walk one of the parkruns I have helped organize here in Canada. But now we have this continuous damned lockdowns for the mildest form of Covid (Omicron) and once again, almost all parkruns in Canada are closed.

[josephhicks]

I'm doing my first marathon on January 15th, 2022, , just over a week from now, and I completed a 20 miler 2 weeks ago. As you said in this video, I did this run to figure out my fueling and pace strategy. My only worry is with my half"s I always have an issue with race-day adrenaline and go out faster than I should.