My PRs for IM and 50M are the same: 10:27. The IM was under fast conditions; the 50M was technical, mountainous and at altitude. I would say I raced both (finished in the top 10% or so).

To me, they're very analogous. Both involve striking a very delicate balance of exertion, pacing and nutrition until you get to the last hour or so, when it's just a brutal fight against extreme fatigue. You can swim and bike more intensely, but you get to stop sooner; running 50 miles involves a lot less intensity (frequent walking, stops at aid stations), but you never get to transition to different muscle groups, etc.

The training for an IM is undeniably harder. But on race day, if I wanted easier, I think I'd choose an IM over a 50M.

Well. I think running 13.1 after running 37 miles is harder than running 13.1 after biking 99. I have done 6 IM a few 50's and one 100 which I dnf. For me the 50's are by far the harder to train and do, however I live in Montana and the runs here have lots of elevation, and tech trail. Her are two links to a 20 miler and a 50 k
http://runtherut.com/ scroll down and watch the video
http://winddrinkers.org/ridge-run/
Training to deal with the elevation ascents and descents and to run the distance is hard training for me in my 50's. Now there is a realitively flat 50 moler here that maybe easier than an IM, but I think in general the 50's are harder. Definetly, hands down, training and completing a 100 is way harder. (I know that was not the question). My training runs are as long as my long bike was or more.
Now the social aspect of ultra's are way better than IM's. Its why i have not done a WTC event for 10 years.

Well. I think running 13.1 after running 37 miles is harder than running 13.1 after biking 99.

Shouldn't this read "I think running 13 after running 37 is harder than running 13 after biking 112 and running 13.2"??? Really what we're comparing biking 112 vs running 23.8.

---

"Anyone can be who they want to be IF they have the HUNGER and the DRIVE."

Ha!! Guess I will use the excuse.of not having my coffee before I wrote......or to tired.from.a.long run yesterday.......yep, that did not.make much sense

FWIM, my friend has done a 50 miler and his training load was 1/2 or less of mine for IM training. It would be a dramatically smaller time commitment. Mentally, I have done a 50 mile run, but I expect it to require similar mental toughness to battle that last 10 miles or so.

---

TrainingBible Coaching
http://www.trainingbible.com

You were also at the pointy end of the field. I have no idea on training load when rated by TSS scores ect. For me, I still swim but only 8-10k a week. Its my active recovery. But for in my 50's the training load in someways is harder because its not spread across three sports. For example, that 50k link (The Rut), http://runtherut.com/ (see video on that link,) I will do one long trail run in the mountains of 5hrs. Then another long run of 20 hill repeats. .25 mile hill at 270 elevation gain on dirt, rock.(that will get me 5,000 in elevation ascent/descent, half for the race) In between a number of the repeats I will run out and back a flat mile, then repeats till i hit 20. This will be another 3.5/4 hr day. Then another 3-4 runs during the remainder of the week.

Again I think it has more to do with the race. Terrain ect. There is a 50 here, The Griz, that for a 50 is relatively easy, for that 50 I would absolutely say you are correct. Maybe my response is biased do to the terrain of the races around where I live. So I am still training, when my swims are added at an avg of 14/15 hrs a week. .........apples /oranges.

I've done 3 Ironmans (Fla 2003, Kona 2004 & Placid 2010) and one 50 miler (VT 2014). I found them about equally hard, but it should be noted I barely trained and didn't race from late 2010 thru summer 2014 and took on VT 25 pounds over my Ironman racing weight. Next Sunday, I'll do my 2nd 50 (Rock the Ridge), still hardly training and still 20+ pounds too heavy. That should make it about Ironman hard.

---

2015 American Zofingen Du is May 17.
R.I.P. Chris Gleason

All things being equal, e.g. degree of hilliness, etc, i think it's a wash, i.e. the two are roughly equal in terms of overall degree of difficulty.

---

"Anyone can be who they want to be IF they have the HUNGER and the DRIVE."

I think it depends on the course. Some of the 50's at elevation San Juan Solstice or Jemez I have found to be more difficult than an ironman other not so much. If you found the Ironman easier and really want to stretch your mind do a 100. The 100 is where the rubber meets the road. The highs are high and the lows can be super low.

I've done 3 IMs and Comrades uphill. For me, Comrades was way tougher physically than any of the IMs. Mentally I am not sure. The valleys I remember seemed lower in an IM than at Comrades. Trains was a different story. IM traing is tougher and longer than Ultra running, even with all the hill work.
Borrowing from the who is faster thread, I think it was knowing I could walk it in that lightened it up mentally.

My experience was that the 50 Mile Run (JFK 50 Miler) was significantly tougher to complete than the three iron-distance races (Placid, Canada, B2B) that I've done. Perhaps it was the early climbing and rock hopping on the Appalachian trail during the JFK50 that trashed my legs. I believe that only running (using one set of muscles) taxes muscular endurance a lot more than alternating from swimming to biking and then running (using different muscle groups) over the same period of time.

Never done a 50M, but done 2 IM - both close to 10 flat with 3:30 runs, and 10 marathons (PR 2:39) and one 50K (3:30 ish)

50K (completely flat) was the easiest by far, despite the fact that I hit a huge wall at mile 28, even after going through the marathon distance 16 minutes slower than I was capable. I want to go longer but the idea of hitting the wall 30-35 miles into a 50 miler really scares me.

Marathons and ironmans are about the same for me. I can't walk normally for a week. Both my IM marathons turned into death marches because I had to push the swim and bike a bit to hope for that perfect day and KQ. That perfect day never happened.

Apples and oranges.

As a triathlete, I feel HIM/IM are doable because of the bike leg and "short" run, and ultras (50miles, 100k, 100 miles) are not in the cards because of the repeated pounding for way too long.

Discussing with ultra runners here, they see it the other way around. For them, running for 24h in a trail 100 milers is entirely doable but mashing a swim and a bike leg to that is alien and impossible.

It's really a matter a perspective.

gold star.

Bump for an interesting thread to give us something to read.

It must be a personal thing...I've done 3IMs (CDAx2, WI), and just completed JFK50 last weekend; FMOP for all. It may be that I was a bit undertrained on run durability for the 50, but my legs buckling every time I walk down something never happened after an IM. Personally, the training for an IM requires much more time; recovery from the 50 is going to take longer than after an IM. JFK50 was a good course, in that all the hard stuff is right up front.

Some time shortly after I started doing IM racing (2000), I was told an IM is like running 75. I would tend to agree. Like has been said many times the races are so different. I was probably a tad undertrained for my 50, but physically it was easier than an IM to me. Mentally I was in a dark spot for a long, long time.

---

Brian

200 M butterfly (long course) is a pretty hard race

Now, that's just all kinds of crazy.

I completely agree. I've done 8 IMs and one standalone marathon (15 years before my first IM) and the thought of a single standalone marathon trying for a PR is horrifying. Running 50 miles sounds impossible. An IM spreads the load onto so many different parts of your body vs just running.

There are a lot of different flavors of pain.
But is the "worst" the one you like most? or the one you like least?

Also- why is it that the races that go wrong- end up hurting more than the ones that grow right?

I've done 10 ironmans, several 50k runs, and did a 50 miler with 10,000 ft of gain last month. My legs were definitely more fatigued after the 50 miler but my overall level of fatigue was more with the IMs.

Usually, after an IM, I do not have much leg muscle pain. I walk normal. But, after an IM, I just feel tired for a week or two afterwards. My whole body feels tired.

After the 50 miler, I did not have this same level of tiredness. But, I am N=1

That's pretty much my experience as well. IM seems harder on the body as a whole with a longer term on overall exhaustion, but after 50 my legs would randomly buckle if I stepped wrong or moved too quickly.

And that's why it's so hard to compare. While IM run courses are relatively consistent, a 50 miler could involve anything from technical trails and 15 000 foot of elevation gain and loss, to 201 laps of an athletics track.

Just shoot me.