OK, there’s a couple of assumptions here, but work with me, people… Let’s say my half marathon time is 1:26:00. Various marathon “time predictors” or calculators would say that my marathon time will be “close” to 3 hours (from as simple as “double your time and add 10 minutes” to the McMillan or Galloway calculators). Dev Paul would tell me to negative split the full, so I can run a 2:50 (not likely, but one of my favorite assumptions). My question is . . .how to “pace” a full in terms of mile pacing? For example, no way could I pace it at my half marathon mile pace (as I’d be, rightfully, shattered, at 13.1 miles). BUT do I go out at the predicted marathon/mile pace? If so, I lose any ability to “slow down” in the second half of the race - as I’d already have run the 1st half at goal/expected pace. Using times (pulled out of the air), if my half marathon ACTUAL pace was 6:30/mile, and my “predicted” per mile pace (based on “predicted” marathon pace per above calculators) was 7/mile, how do I pace the race? Do I go out at 7 and hope to hold it (close to the De Paul negative split), or do I go out at 6:30 and understand that I’ll give up a bunch of time in the 2nd half of the race? Split the difference and hope for the best? Other?
Having only run two marathons (and #3 being NYC next weekend), I’m definitely far from an expert. However, most ‘successful’ marathoners aim for pretty even splits, if not for a tiny negative split. Most elite runners aim for around a 1 min negative split. Look at NYC from last year - the winner for the men closed with a 10K @ 4:40 pace, negative splitting the course, and running the second half 4 seconds faster per mile than the first half.
I personally will be trying to run close to ‘even’ pacing, allowing for wiggle room of 5-10 seconds per mile over/under my goal pace after the first mile or two. My goal will hopefully be to run a strong last 10k, either maintaining my effort, or upping the pace. Some courses definitely have to be looked at closely, and your plan for the race needs to be dictated by the layout of the race. Greg Maclin has done this for many of the larger races, making wrist band pace sheets for many courses.
Having said all of this, most first time marathoners have pretty big positive splits. They go out too hard, feel that the pace is easy, but then crash and burn and shuffle in to the finish. Don’t be one of those guys! The first 13.1 should feel easy and relaxed, and up to 20 should feel a bit hard. The last 10k will hurt, regardless of who you are. That last part is largely mental, knowing that you’ve put in the training and can run your goal pace even though your legs are hurting like hell.
May I assume that your question is practical (not really hypothetical) for doing your 1st marathon, even though you’ve been registered on this site for 9 years?
If so, forget the pace calculators. Do not have a goal finishing time that others will admire and plan on a glacial pace for the front half. The goal is simply to finish with a smile in your heart.
I agree with what you’ve said, but . . .I’m not sure it really answers the question. Based on the above “hypothetical” times, and what the “predictors” indicate a result would be, how would you pace? Would you pace for a 3 hour race (results of using predictors) - with mile splits set at about 6:52? or would you go out sub-3 (again, just using this an an example) with an expectation of slowing XX minutes in the second half?
I agree with what you’ve said, but . . .I’m not sure it really answers the question. Based on the above “hypothetical” times, and what the “predictors” indicate a result would be, how would you pace? Would you pace for a 3 hour race (results of using predictors) - with mile splits set at about 6:52? or would you go out sub-3 (again, just using this an an example) with an expectation of slowing XX minutes in the second half?
I won’t go there because having coached many marathon training clinics for first timers, using pace calculators is a fool’s game. Sorry.
I recommend running an even “effort” race. If the course if flat, that usually means even pace. If 7:00 pace is your estimated target pace, you should run 7:00 splits.
The problem with banking time in the first half of the marathon is you’ll burn too much glycogen. The problem with trying to negative split is muscle fatigue may make it very challenging to pick up the pace.
Really, don’t overthink it, run even splits.
I’ve done a half dozen marathons, including a BQ, with varying levels of training and success. First off, the marathon pace estimators only calculate a pace for a fully trained athlete. This assumes you don’t bonk. Fully trained means probably a minimum of around 60 miles per week leading up to the marathon, though I’ve finished in good shape with as little as 40 miles per week. The calculators predict around a 3:00 off your HM. I would start off at that pace, and see what it feels like. Slow down if you have to. Early miles should feel easy. After about 8 or 10 miles the perceived effort will go up, until at about mile 18 you are working pretty hard. From there on it’s all about how well you have managed pace, heat, hydration, and carbohydrates. Don’t be surprised if you have to give back 5 minutes or more past mile 20. I have had some luck with carbo loading, and recommend it to prevent bonking. The magic number that worked for me was three days at 10gm/kg per day.
Good luck.
Banking time never works because the ratio of glycogen to fat that you’re burning is too high, so you’re going to complete decimate yourself if you’re running too close to threshold early on. At 1:26, unless you’ve been running over 50 mpw for the last 12-18 months, I think breaking 300 would be tough, but going under 310 would be a reasonable goal. I’d probably shoot for 305, and be very, very careful not to overrun the first 10 miles.
The fact that you’re even asking your question, means that you’re new to marathoning, and as a result, I’ll predict with confidence that you’ve got no shot at a 2:56 unless you sandbagged your 1:26 half.
I’d go so far as to say you’ll be lucky to even get a sub 3:10.
The marathon is a tough race. Unlike the shorter distances (HM down to 5k), there is a real long-distance endurance component that simply isn’t taken into account by Mcmillan and other calculators. As a result, those calculators tend to work very well when extrapolating from the marathon backwards to 5k, but are almost invariably “best case optimistic scenarios” when going from 5k-HM to marathon.
Experienced runners doing 70+mpw and having several marathons under their belt already have a hard time hitting a Mcmillan estimate (HMx 2 + 10min). The odds of a beginner marathoner on low mileage doing this, while possible, is low. I’d give your estimate HM x 2 + 15-20 as a realistic estimate.
I definitely wouldn’t run the first half any faster than 3:10 pace (1:35 half), even if you feel great. The cliche statement is true - you’re not even close to the halfway point at mile 13 - the halfway point is mile 20, not exaggerating. If you can still accelerate at mile 20, you’ve done a great job pacing. Odds of a beginner being able to do that, even with conservative pacing, are not good. Odds are far higher that you’ll cramp and slow down by huge amounts around that mile mark.
FWIW - my PR with high mileage was a 1:25 on a very fair but flat course, and my marathon run on only a slightly hillier course during that time was a 3:12. With 4 prior marathons under my belt before that.
Just to add to my thread above, since it was a bit verbose and didn’t answer your question directly:
As a beginner, shoot for at least a 5 minute negative split. It wouldn’t even be unreasonable to shoot for a 10 minute negative split.
Whatever you do, do NOT aim to pace out at your “A” race time (which would be sub-3) and try to hold on. As a person new to the marathon, there is no way you’ll be able to do it.
A 1-2 minute positive split is very, very good pacing for a 1st or 2nd marathon, even for a fast runner. I can’t even remember a single case I’ve seen of someone negative splitting by 4-5 minutes in the marathon, even on a favorable 2nd half course. I actually threw down a 5 minute negative split in the San Francisco marathon, which has a uphill first half and a downhill 2nd half, and even with that favorable topology, I felt like I was doing something like a 15 minute negative split since the 2nd half felt so, so fast.
I think you make several good points. The bottom line is most people experience “glycogen depletion” in the marathon because they are racing too close to threshold and/or haven’t trained sufficiently in increase glycogen stores.
FWIW, I use a heart rate monitor and start my marathons about 10 beats per minute (bpm) below my lactate threshold (LT). At this effort, I estimate that I burn a mix of about 60% glycogen / 40% fat.
Seriously, don’t do what I did this morning and assume that you can run any particular pace before your first marathon. I added 30 minutes to my McMillan calculated time and figured I’d be good - and ended up with a 25 minute positive split. It was not fun. It was not over quickly.
Optimal pace is even effort, ie it would be even pace on a flat course.
Part of the trick is the difference (it can be a huge difference) between effort and perceived effort. At an even effort, it will feel too easy in the first half, and murderously hard from about 25 or 30km. The common advice about aiming for a negative split is, I believe, to discipline you to slow the beginning and dig hard in the end, rather than to start too hard and accept the consequences of fading late. Even if you aim for a negative split it is likely that you won’t. I agree that a couple of minutes positive split is probably a good result. Any negative split should only be by the minute you claw back in the final kick when you give it everything you have left.
So, start as you have realistically assessed you can continue to the end, then continue to the end. Planning to “give up a bunch of time in the 2nd half of the race” is, if not quite planning to fail, at least planning to do a sub-optimal performance.
Go out at 6:45’s for the first half. Then see what you’re made of in the second half.
I’ve run 6 or so marathons. usually top 5 AG ( not a back door brag just putting advice into context…i.e. I have had some success)
My last was my best and I went for even pacing. Got pretty close to even and positive split by about a minute and a half.
I think the question though is what pace should you start with?..If I were you I would go for the 3 hour mark. You will probably finish ant 3:05 or 3:10 but who the hell says to themselves ’ hey I’m going to do a 3:05 marathon’…hit half way in 1:29-1:29:30 ( given you can do 1:26 this is still not too hard a pace). Then if you are feeling OK don’t speed up keep the pace. (If you are starting to hurt at half way you are cooked and slow down to a 3:10 finishing time pace…dont keep at your intended pace or you will have a very long day. )If at 30KM you still feel OK then keep on your pace but know the effort is going to increase greatly from here on in. At 35KM you will be feeling really rough and will be trying with all your might NOT to loose the minute you had in the bank from the first half. The last 3Km will be about as hard as you have ever run. If you hit 3 hours give yourself a pat on the back and have a chocolate milk you overachieved!
If you are under 3:10 way to go dont feel disappointed at all…learn what you can and improve traing for the next one!
Over 3:10 …strategic errors or a bad day.move on!
Thanks for the responses so far. If it matters it’s really not for me but is quasi hypothetical. A friend is training and we were throwing thoughts around. All the science is too high brow for me. I’m just dumb enough to go out and run as hard as I think I can…and try to hold on.
Let me change the question a bit. Assuming the above is still true should workouts be done targetting the 3 hour pace or should workouts still be done at a faster pace if they can be done that way? For example mile repeats at a given pace or 5 mile tempo efforts. Should those paces be the 3 hour Marathon goal pace or faster assuming the body will allow for it?
Put 1:26 half into McMillan and use the resultant paces for training. They are close enough.
Most larger marathons have pace groups. I’d use one of these to control your pace. Also, running with others with the same target should have some mental benefits then being out there by yourself so to speak. It would appear from the above responses your odds of a negative split are slim. I would tend to agree. I know everyone is different; however, even in my training runs of 20-22 miles, I don’t have much left in the tank. Those are also at paces 30-40 seconds per mile slower than my target pace.
That being said, you have a tough call to make if you choose a pace group. 3:05 and positive split to the 3:15 group or 3:15 group and pray to hang on (or whatever group you pick).
Best of luck.
Thanks for the responses so far. If it matters it’s really not for me but is quasi hypothetical. A friend is training and we were throwing thoughts around. All the science is too high brow for me. I’m just dumb enough to go out and run as hard as I think I can…and try to hold on.
Let me change the question a bit. Assuming the above is still true should workouts be done targetting the 3 hour pace or should workouts still be done at a faster pace if they can be done that way? For example mile repeats at a given pace or 5 mile tempo efforts. Should those paces be the 3 hour Marathon goal pace or faster assuming the body will allow for it?
If you think you’re up to snuff for the sub3, you should definitely be hitting the Mcmillan paces at or exceeding the training speed recommendations nearing race day, like in the 2-3 weeks before that, if not earlier. You might not be as fast if you’re early in a 14-18 week cycle, but you should be close.
Definitely not a good sign if 2-3 weeks prior to race day you can’t sustain the Mcmillan paces for real marathon training volume.
Overall though it’s still best to train at your correct ability and not an imagined one. So plug that 1:26 in, see what it recommends and start from there.
And FYI - if you actually think you can HTFU through the entire marathon from mile 1 and just run as hard as you can as long as you can, there is a 110% change you’ll blow up at mile 20-22 and death march the final miles in. Even the fastest guys don’t run effectively by gunning out from mile one and hanging on for 26 more. You can do that in a half marathon for sure, but it’s not going to work in a marathon. If you pace correctly, miles 0-13 will feel almost easy, and it won’t really get hard until mile 18, which is about when the real race begins. (So if you haven’t done many 18+ milers in training, you’re in for a rude awakening as well when you suddenly realize you’ve on trained for the true halfway mark in a standalone marathon.)
+1
Bad pacing in a HM could cost you 2-3 minutes. Bad pacing in a full marathon could cost you 10-20 minutes. The first half should feel insanely easy. That same pace you run in the first half should feel insanely hard after 20 miles. Running a good marathon takes good training and good planning. I don’t see it being possible to “gut it out” in a marathon. When your legs shut down from glycogen depletion gutting it be the difference between walking and shuffling.