Longest Run in IM prep

3-3:30

That usually equates to 18-20 miles for me.  I asked this question of a couple coaches on BT years ago and they said this was fine, no need to go further.  I accepted that.

Other "proof" was that in open marathon plans, you also rarely do more than 20 mile runs (Hal Higdon).

Rather than asking what your longest run would be, I would rather ask how much total volume per week you plan to run.

95% of us would see increases in run fitness simply by running more.  Doesn't matter if you add that into your weekly runs or your long runs.  Keeping your LR as a lower % of your weekly mileage would also help prevent injury.

In all honesty, if you're not running more than 30-35 mpw...the distance of your long run isn't your biggest issue.  You could do just fine running 5x per week, 4, 7, 4, 7, 12.  Running 3, 6, 6, 18 doesn't seem like a better running plan to me.

Take all this advice knowing I have never done an IM. 

I did three hours. It was slower than I would have trained for a stand-alone  marathon but it got me about 27k (if I remember correctly) which I was comfortable with for my IM prep.  I don't think i would have picked a plan with a 2:30 long run just because I have run 5 stand-alone marathons and know my pacing well enough that I wanted to be somewhere in the neighbourhood of 30k as a long training run.  A 2:30 run wouldn't have gotten me close - especially in the heat of the summer.

To me, a 2:30 long run is for faster runners or someone who doesn't have much run mileage and should be conservative and save the recovery time from doing such a long run.  I didn't go into the run portion of the IM with high or aggressive expectations since there are so many factors that go into having a good run - i felt it was really important to be just as comfortable with the bike and swim. 

If i remember correctly - my longest runs were 2:30 and  3:00 and I had what I consider to be a pretty good run split for the IM distance (expected to be around 5:00 and came in 4:46) especially for my first.

I posted this in the time vs distance thread...

As for the run, one must do what is practical from a recovery standpoint.  The recovery equation not only includes the physical recovery from the run itself but needs to factor in what implications that run will have on future workouts.  One can't expect to have a really good bike ride or run in the day or two (or three) following a 3+ hour training run.  I think the occasional long run (every three weeks or so) is probably a smarter choice for most AG'ers as long as they don't ignore the volume the other two weeks.

Two 2.5-hour runs and one 3-hour run (plus a 70.3 where my run was around 2.5 hours).

I'm a slower runner so my coach wanted me to get three of those long runs in. My 3-hour run yielded me 16.64 miles.

My longest run for IMLP prep was 3 hours/20 miles. I did this late June, about a month out from race day. I also did a 2 hr and a 2:20 in May. Feel free to check my logs from 2011. March to July was the primary period.

5/7
14.5 Mi - 2h 02m 29s 
08m 27s/Mi 

5/29
16.02 Mi - 2h 20m 09s 
08m 45s/Mi 

6/25
20 Mi - 3h 02m 07s
09m 07s/Mi 

As others have said, it is very dependent on your training and running history. For an open marathon I'll do 4-5 20-22 mile runs, which means I'm on my feet for up to 2 hrs 40 minutes or so. For my IM in August I imagine I'll probably do at least 3-4 runs in the 2.5 hour range, but my coach will decide on that. Weekly volume trumps one or two long runs. If you can be running 30-40 mpw nearly every week that will make more of a difference than one long run will.

It isn't as important to do as many long runs for an IM as it is for a marathon. In an open marathon you are going at a substantially faster pace than in an IM marathon. Your IM run pace should be the same as your every-day easy pace. Your goal in the IM run is to simply maintain that pace, and most people falter and cannot do it.

You guys honestly amaze me.  When I saw some of you say 2:30 long run, that seemed short, then i saw the mileage was 18-20 miles it blew me away.  I can't imagine being able to run that far that fast.  My longest training run for my IM was 3 hours which yielded a whopping 15 miles.  

I really hope to get where you many of you guys are, that's awesome.

x2, which is why the "one size fits all" mentality does NOT work here!
Many different approaches are successful. 

My longest was 3hrs/22 miles. Not sure it done me anygood though. Like someone already said here there are so many factors in IM. I think I ended up 5:50 ish on the run. (being a runner I was sorally disapointed)

That's a pretty decent training run time (the 3:00/22 miles) which obviously didn't translate on race day.  Do you know what happened?  Correct me if I'm wrong but it was either bike fitness, bike execution, bike nutrition or some combination.

I'm not trying to be a jackwagon as I'm going to try and illustrate a point so my points may or may not pertain to you.

I'm bound to catch some flak for this but here goes... long run training is way overrated for most IM AG'ers.  You'll hear things said like "It's not all about the bike."  Well, for MOP/BOP AG'ers it's pretty much all about the bike.  Neglecting your bike training, overcooking your bike on race day and boogering your nutrition on the bike is going to make the run a slow and horrible experience.  It shifts to "It's more about the run" at the FOP.

Get in the proper weekly volume, don't fixate about "how long" my long run is and it will work out fine in the end.

My peak month long runs were 2:00, 2:15, 2:30. 2:45, 3:00.  

I did cut the 3hr one a bit short (stopped at 20m) as three hours would have taken me 21-22m and had no desire to go that far (I don't run that far in marathon training).

The quick answer is NO.

I think it was a combination of things. I had a horrible bike mainly nutrition I did not execute properly. When I finished I still had more than half my nutrition for the second half. I also may have pushed it to much on the bike training I had several rides over 100 and one 120 looking back that may have not been smart because I was also trying to do the same thing with the run. I would run 18-20 miles on Thursday and ride 100-120 on Saturday. (My training schedule was by hours and I was going well over the hours becasuse I wanted to get the miles I was afraid of not doing enough and my have done to much For my level of fitness). On race day I was not 100% rested. I should have asked more questions here. I don't personally know anyone that does IM and I didn't have a coach.

My way of thinking was more is better.

I didn't think you where being a jackwagon.

My longest run for my IM was 2:43 (20.3 miles) -  the plan called for 2:40.  As far as the "why", it was just balancing everything and not wanting to kill the legs too much.  I had run 12 marathons up to that point, so wasn't terribly concerned with running any longer for IM training. 

I plan to follow a pretty similar plan for IMLP, though I've been facing a nagging injury that is slowing my running down.