Which is harder sub 1 hour 10mile or sub 3 marathon?

No way. That's like a 1:19 half and you couldn't break 3? You must have been sick or injured or over cooked the first 20 miles. Fitness was there for sure.

The sub 3 SHOULD be easier, however that has not been my experience. I've had many buildups where I've run well under 1:20 for the half and then failed to break 3 for the marathon. One time I ran a 1:16 half (going through 10 miles around 58 minutes) and finished feeling pretty good. But a month later, I only managed a 3:01 for the full marathon. I have broken 3 a couple of times, but my full times are always way worse compared to my half times.

My best half from years ago was 1:12, but that only got me a 2:48 marathon a month later.

Wow! That’s nuts. My anecdotal experience is sub 3 is easier. I’ve never run more than 50-60 mpw. When I have trained at that level (in my mid 30s at the time) I was only able to manage a 1:03:xx 10 mile but a 2:57:xx marathon—both on fast courses in good weather. Maybe it’s a speed thing? Sub-6 minute pace has always been tough for me—physically and mentally. The longest distance I’ve been able to maintain sub-6 for is the 10K.

Sub-1:00 10-miler is harder, but not by much. I've run low-2:50s in a couple marathons but could never quite get under the one hour mark in the 10. Just over.

It's 2:47 on a JD table.

It plays to people's skill I suppose... but in training as a mid 2:30s runner, I would say that I run a low 2:50s as a long run and it's fairly comfortable. I could probably still do it fairly untrained. But running a 59:59 would be a pain.

Last autumn I ran a 2.53 Marathon and 3 weeks later a 1.19 Half. In my experience a sub-hour 10miler equals to faster times in a Marathon than 2.59

The St Albert 10 miler is not a difficult course. In fact, I cannot think of a single 10 mile race in AB that would be considered difficult, unless you are talking about a road relay leg.

I agree with you about that, but the point is a 22 year old 5km runner might easily run sub-60 like it is nothing, but any marathon would be hard.

The problem with the "sub-3:00 marathon" isn't the sub-3:00 part, it is the marathon part.

The marathon in and of itself is hard because of how the body responds to a 3 hour run. If this weren't true, then fit, young 800m and 1500m runners could easily, "jog" a sub-3, but we all know they can't.

I think it's a toss up. Physiologically, the sub 60:00 ten miler is probably more difficult because you're accumulating lactate faster, etc and therefore the fatigue hits you faster. But biomechanically, even with newer shoes, a full marathon takes a lot out of you; all the pounding on the calcaneal tendons and quads for hours.

If weather was equal for both attempts (say 45-55degree range) I'd say dipping under 3:00:00 would be a tad easier (if you've trained for it fairly well). My team did a lot of ten milers in college where we ran in the 55:00-58:00 range. Hitting sub 6minute pace from the start, or even working down under it by say 3-4 mile mark was always pretty tough I thought. Running with 6-7 other guys on a team made it easier but it was still tough. Sub 6:00 pace, even if you're say a 14:30-40 5k/30:30-31:00 10K type (most guys on my team eventually ran close to those or equivalents) can become mildly uncomfortable after a few miles, especially if you're having a slight 'off' day in your training. Just my experience. I used to think during those ten milers that people running that effort for a marathon were pretty tough. I had a friend who ran about 54:55 for ten miles enroute to a 1:12:14 1/2marathon but never broke 2:56:00. Think in several attempts all he got was like 2:56-7 range even though in one of those he went through 1/2way in 1:21 feeling good but blew up the last 4miles due to humidity and not hydrating enough. I think the earlier poster who said there's more variables to consider the longer the effort was right. Not apples to apples per se.

Without a doubt, 10 miles in 60 minutes are more difficult

I'd agree with the above, and it very much it also depends on the runner.

My best distance has always been around 3000m. When I was younger, my training runs were generally in the 6:00 mile range (only ran 40-50 miles a week other than marathon training).

A 60 min 10 miler would have a regular training run - actually a fair bit slower than some of our winter training runs - very comfortable.

I ran two marathons 2:47.30 (with virtually perfect splits) and 2:52.xx (went from cruising and passing people at 21 miles, to bonk at 22). A 3:00 marathon would have been relatively easy from a cardio vascular standpoint, but it would still have beat the hell out of me.

On the other hand, I knew someone that well into my 50s, I could beat over 5k, who broke 3 hours for a marathon, and ran a good 10k a week or two later. At that point, I doubt I could have broken 3:15 for a marathon.

The course is different now from when I did the race. It used to have a substantial climb at 7 miles. It is also over 2k feet above sea level which makes a difference.

For me, sub-3 was much harder. But that’s partly because I was running Boston each year and having bad luck with weather. The year I finally broke 3, I ran a 58 minute flat 10-mile time trial on an indoor track and 2:56 at Boston (88 degrees at the start that year)

This is exactly it. The marathon is a beast. I have run 14:56 for 5K and 31:08 for 10K. I've run sub 60 several times in training runs, but I could never break 3:00. Just too much room for error.

I find it somewhat amazing that a 31 min 10 km runner couldn’t breeze a 3 hour marathon. That’s a hell of an offset. I understand respecting the distance and getting some decent longer runs in but still…..

This is the correct answer. That is to say, "it depends."

My first ten-mile was 59:xx, off of 36:xx 10k fitness. It was the longest I had ever run at the time.

I did a 1:22 half marathon a month later, but probably couldn't have finished a marathon, let alone broken 3:00. I had literally never run longer than 90 minutes.

I think that almost any college XC runner could do a sub-60 ten-mile. While this predicts a marathon time much faster than 3:00, those predictions all assume adequate training for the marathon. As Ruxton says, a lot of these runners whose shorter times say they are "good for" 2:50 or much faster will DNF or bonk to 3+ hour marathons.

When a calculator says you 1:00:00 ten-mile is "equivalent" to a 2:47 marathon, that really means you likely have the speed, VO2 and lactate threshold for it, which can be demonstrated in a shorter race. These tools for an solid ten-mile are necessary but not sufficient for an equivalent solid marathon, which also requires muscular and metabolic adaptations well beyond what's needed to run hard for an hour.

Newer runners will often have the speed, VO2 and threshold but lack the longer-distance adaptations. Older runners will often have the opposite set of abilities.

As an older runner now, I can break 3:00 but may never tempo at 5:55/mile again.😭

For me the 10 miler is easier and I run about 36:30 for 10k.

I've done 2 marathons so far and after feeling fine I began to struggle in the last 3-5 miles.

Me too. 62 for 10 miles but sub-3 a whole bunch of times.