How hard is a 100K?

It is easy you just have to keep going. I am a 2:22 marathoner and I did an FKT two days ago that was 97K in 7 hours. It was totally flat but I was surprised at how easy it was. I know it is changing now but ultra runners just are not that great of athletes.

Tbrownruns wrote:

It is easy you just have to keep going. I am a 2:22 marathoner and I did an FKT two days ago that was 97K in 7 hours. It was totally flat but I was surprised at how easy it was. I know it is changing now but ultra runners just are not that great of athletes.

What is your MPW? Did you do anything special in training?

Currently doing 100 mpw (in doubles, easy running, or two hard workouts, long run not crazy 15-20 miles). Thinking about attempting a FKT in 2 weeks- 78 miles, flat gravel bike path. I have 2 50ks, and 2 36milers with 9k of elevation gain under my experience. What do you think?

A 100k will be very hard starting around 70k.

It's all mental at that point. If you are prepared for it, you will get through it. If not, you will fail, no matter how fast your Marathon time is.

9 hours is possible but don't get hung up on numbers. Just make sure you keep going. Either running or walking.

Good luck!

I was at 100-115 January through March but since corona cancelled all my races i have been like 60-80. I think if I had been doing more miles the last couple hours would have been much easier

Depends on the course -- flat is pretty straightforward (and boring). Just eat/drink enough and take the pace easy, and it won't be too bad.

But on courses with big elevation gain, faster runners sometimes struggle with pacing climbs appropriately, and blow up well before 50k. That's where doing real long runs and/or back to back long runs helps (so you get a better feel for pace on tired legs).

Just like a marathon, finishing one is easy. Racing one is hard.

Harder than a 50K, easier than 100 miles.

5 x 18 is the answer. That workout doesn't get enough love on this website.

you can do it, but as you've already heard, don't take that time conversion too seriously. I'm in same ballpark as you for marathon and ran JFK 50-mile in 8:32 last fall -- something tells me I couldn't have covered another 12 miles in 28 mins.

And obviously you might be better than I am at ultras, but I'd still say for a first 100k to factor in the course difficulty and weather, and then still add a big uncertainty factor. You'll be out there a long time -- plenty of opportunity to make up time if you find out that you started too slow and feel great

good luck with it -- should be an adventure.

--Dave

I've read that a good conversion factor the first time out for the 50 miler is 2X marathon time plus two hours. So, a four hour marathoner is looking at 10 hours for 50. That's 12 minute pace. I'm starting to train for a first ultra, not sure whether I'll go for a 50 miler or a 50K. It's a whole different game trying to lay down lots of slow miles and in working up weekend doubles that's going to feel like a lot of time.

But I'm in my 50s and my average training pace has dropped to the point that marathoning would be slow enough to be demoralizing anymore, but I've also gotten very good at dieseling, going nice and slow for a long time. It's the perfect transition for those of us who can lay down lots of miles but cannot go fast anymore without risk of injury. The struggle is going to be the psychology of the slowness. Jesus, weekends are going to start to look like four hours out on a Saturday and six on a Sunday. That's the whole weekend eaten up.

We'll see.

Wow, thank you guys for such insightful responses!

However, on a second thought, I am gonna skip it this time around considering my mileage this year has been very low (averaging around 50km per week, and the max being 65kms). I think I will be able to do it, but it will probably be very slow and risk some injury.

ultra_newbie wrote:

Wow, thank you guys for such insightful responses!

However, on a second thought, I am gonna skip it this time around considering my mileage this year has been very low (averaging around 50km per week, and the max being 65kms). I think I will be able to do it, but it will probably be very slow and risk some injury.

I'm not sure mileage is the answer anyways. Same boat as you in terms of # of marathons and time. My weekly mileage was ~50mpw at the time of my first 100k. It was by far the hardest endurance event I've done. Much harder than Ironman, much harder than a marathon. Problem is, the weather changes like five times in that spa. I started crapping out around mile 22, once it warmed up and the sun was high in the sky. Once it went down, I got a second wind and was able to run fine for most of the way. It was mainly mental, however.. mental and fueling. And mental. Your body is toast early on; you just have to convince yourself you can keep going.

Would love to hear from more ultra runners in this thread. I had a good friend who ran lots of ultras including the big 100 milers around the country. Their typical method was to load up ungodly on weekend miles. 40 or more on Saturday and another 30 or more on Sunday. I couldn't imagine at the time, but they did these miles very slow with lots of walking and lots of hilly terrain.

The Sunday long run on absolutely dead legs was apparently the big challenge and they had to master being able to keep moving, hydrated and fueled on Sundays to become competent at the events themselves. It's a grind.

Ultras are a thing, totally not like distances marathon or less, appealing to me at my age and (lack of) speed.

Tbrownruns wrote:

It is easy you just have to keep going. I am a 2:22 marathoner and I did an FKT two days ago that was 97K in 7 hours. It was totally flat but I was surprised at how easy it was. I know it is changing now but ultra runners just are not that great of athletes.

was this road or trail?

97k in 7 hours wouldn't be much of a race for a 2:22 guy (on pavement)

and if you think it wasn't that hard...you did something wrong. running a 2:22 marathon is easy if you're in 2:15 shape, so maybe you just didn't run hard enough.

Tbrownruns wrote:

It is easy you just have to keep going. I am a 2:22 marathoner and I did an FKT two days ago that was 97K in 7 hours. It was totally flat but I was surprised at how easy it was. I know it is changing now but ultra runners just are not that great of athletes.

What trail did you get a FKT on? Or if you don't want to answer, where would one find fkt for long trails? Is there actually competition outside of a few well known trails?

ultra_newbie wrote:

A friend is proposing me to do a 100K in September. Have done about 10 marathons in the last 15 years, ranging from 3:32 (first one) to 3:01 (fastest). Last one was 2 years ago (a 3:13). Will I be able to up my mileage in the next 3 months to be able to make it? According to this link, I could multiply marathon time by 2.8 to get a rough estimate. (

https://www.enduranceplanet.com/ultrarunning-training-guidelines-for-a-100k/#:~:text=To%20get%20a%20rough%20estimate,untoward%20happens%20during%20the%20race

.)

Ah, 9 hrs of running, doesn't sound so entertaining....but would be a nice "I have done that" badge to own :-)

How hard the ultra will be depends on the terrain as well as the distance. Is it on trails? Hilly? On a flat, smooth rail trail? Train for the terrain as well as the distance.

No need for 4 to 6 hour runs on the weekend unless you are world class.

Do a 50k and work yourself up to a 50 miler.

Also you can't compare a flat road 100k race to a mountainous 50 miler. These are two entirely different things.

Kvothe wrote:

How hard the ultra will be depends on the terrain as well as the distance. Is it on trails? Hilly? On a flat, smooth rail trail? Train for the terrain as well as the distance.

How hard the ultra will be depends on the pace. Nothing else.

Running a flat 100k under 8 hours is harder than slogging out a 100 miler in 30 hours.

almost all pavement but the guy above is right i did not try very hard. No FKT is hard until good people do it .

https://fastestknowntime.com/fkt/t-roy-brown-lake-zurich-circumnavigation-switzerland-2020-06-13