The Sub 3:15 Marathon Thread
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336 watchers
11 Jul
2:44pm, 11 Jul 2025
27,684 posts
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larkim
@jda ah, yes - you're correct. I recalled the "proud" word but misassociated it. Anyway, you and SPR are inferring a level of effort (as am I) and neither of us has any insight as to whether he was running maximally or not. To me, the very fact that he's talking about the wall suggests to me that he was running it to a max effort. But you may differ. Wouldn't be the first time... And if you think 80g/hour isn't something relevant to runners as well as cyclists I think your understanding is out of date. For running, cycling, triathlon, etc we're well into that world now *at the elite end and for those trained with a gut to handle it*. |
11 Jul
2:47pm, 11 Jul 2025
18,965 posts
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jda
Huh? I was taking him at his word that 80g was more than runners accepted. If you’re now saying it’s standard practice, what exactly was the point being made?
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11 Jul
3:02pm, 11 Jul 2025
27,685 posts
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larkim
Happy to have that clarified; my bad if I misunderstood your post. I do think he is correct though to say that the amateur running community has taken longer to move towards the higher carb consumption world, even if there are some enlightened folks already on here. Maybe (as usual) I'd exaggerated the 15+mile start point, but there is still a decent chunk of legacy advice around about waiting an hour or 90 minutes into a marathon before taking the first gel etc. |
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11 Jul
4:04pm, 11 Jul 2025
18,966 posts
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jda
Certainly 80g per hour is far more than I’ve ever managed when running hard, but objectively he was running very gently indeed in terms of his aerobic capacity. And while the +3 split that he did is respectable enough (and I’m sure he overtook a lot of people) it’s hardly exceptional.
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11 Jul
4:38pm, 11 Jul 2025
27,688 posts
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larkim
This is his Pretty similar HR profile to mine on the same day for the marathon, his started a bit lower and rose a bit higher. Looks like his overall HR profile not massively different to mine in terms of range. |
11 Jul
8:38pm, 11 Jul 2025
652 posts
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Charlesvdw
1. An elite runner takes in about 90 grams of carbohydrates per hour and takes 2 hours and 10 minutes to complete a marathon. 2. A very important point : energy expenditure depends on the distance covered and is approximately 1 kcal/kg/km. 3. So someone who completes a marathon in 4 hours and 20 minutes will have the same total calorie expenditure but spread over a period twice as long. Hence for this person (let's suppose his weight is equal to the elite's) 45 grams of carbs will be sufficient. |
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11 Jul
8:42pm, 11 Jul 2025
653 posts
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Charlesvdw
Be free to disagree. On a personal note, I can take in 50 grams of carbs the first 2 hours but after that I've had enough. |
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11 Jul
10:05pm, 11 Jul 2025
27,689 posts
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larkim
No disagreement that slower speed = slower calorie burn, though inefficiency of slower runners moves that dial in the opposite direction too. And 90g/hr is starting to look low. 120+ is being used certainly in the pro cycling and triathlon world, and some recent studies have shown that as you increase the consumption even though your percentage usage may drop, the absolute amount of carbs oxidised can still rise. There's loads of good stuff on this on Ross Tucker's podcast; the impression given, backed up with some scientific credibility, is that this is an area of sports science which is moving pretty rapidly. There's some good research done on race walkers in particular. Clearly there are some benefits for cyclists which marathon runners might not need; carb use on day A during a race giving some recovery benefits which roll into day B etc etc. I'm probably the last person in the world to take this on board - my miserly approach to cash will mean I will not be conducting any gut training with carbs any time soon, so the max I'm at of 2-3 gels per hour will probably stay in place. |
14 Jul
3:28pm, 14 Jul 2025
67 posts
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PJH92
Had my own slight carb disaster on my 'long' (15 miles) run yesterday. Had to go out about 4pm as it was the only time that worked, was still incredibly hot. Took one SIS Beta gel (40g of Carbs I think) and 250ml water in a soft flask. Took the gel at 7/8miles, got to 12 miles and was crazy lightheaded, had to do an emergency stop at a corner shop to buy a lucozade, necked the whole bottle and made it home in once piece. Think I made the rookie error of not dialing it back in the heat, not particularly eating a decent lunch then not taking enough with me for a 2hr run. |
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14 Jul
4:59pm, 14 Jul 2025
27,692 posts
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larkim
Oof, 4pm here was the hottest part of the day. A brave choice!! Glad you got through ok! |
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