So why’d I bonk and what should I fix next time?

More gels. A gel takes ~15 mins to kick in so one every 45 is probably not enough energy in for you. Especially if you are just consuming water. Assuming they are 100 cals each, that is only 300 over the course of a marathon which if you are pushing yourself is not enough.

The quick answer like it or not is more miles. You’ll usually want 60+ mpw to help eliminate that bonk. You could however re-arrange that 40 mpw. If you can get your long run within a few miles of race distance that’ll help a lot. You can run it easier too, you just need to get your body used to the caloric demand.

Looks like you did everything right.

The problem is, Marathon running is hard, especially when you hit the wall around 22 miles.

Maybe you paced yourself too fast other than that, more miles are the answer.

hey, I have run 2:24 and 2:27 in the marathon, I think I have the nutrition and training pretty well figured out (at least for myself, though it would likely be useful for you) I would be happy to offer some advice. I would even be thrilled to write you a plan or offer some coaching. I am a huge running nerd and I would just love to help a fellow runner out

While I would agree with the other posters on here that more miles would be ideal (maybe just shoot for 50 instead of trying to get to 60), you could also try actually extending your weekly runs and decreasing the distance of your long run. I know this sounds counterintuitive but I had great success with 3 big negative splits in my first three marathons (all 3 easily BQs) by running 16 mile long runs and 11-12 mile daily runs (yes I realize that this totals more than 60 miles per week so maybe you could try something like 16-17 & 10x 4?). The accumulated fatigue of significant time on feet during the week can be a more beneficial training stimulus than just one long effort that you essentially recover from during the entirety of following week.

Also, if this works, I found significant success training for my OTQ (slowed toward the end due missing all the aid stations (big mistake)) and the Trials themselves (very strong race and PR in ATL) by running "back to back" long runs (Saturday being usually the highest mileage with a big dose of speed work at marathon and half marathon goal pace incorporated up to 22.5 miles and Sunday with an easier but still solid LR of 16-19 miles). I include this second part of my response to explain that once I had hit my goals with the 16 mi LR & 11-12 mi daily run, I was able to increase to 2 x LR at 16-22.5 mi & 12-13.5 mi daily run over time but that initially, I did very well with shorter long runs and longer daily runs (I understand that this could be difficult for someone with a very limited amount of time during the week).

More mileage & go out a little easier. Good Luck.

Well a bonk specifically refers to a depletion of gylcogen. So that was easy. Next question?

Solid 1st marathon! More miles is pretty obvious. Not everybody can run 100mpw but 40 leaves you a lot of room for improvement. If you're not willing to try 50-60 then future marathons will probably go about the same. 40 & maxing out around 20 (1/2 of your weekly mileage) seems like a good starting point to me.

If you're committed to 40, maybe think about doing that in 5ish runs/week with a day or two of cross training. Speed work is good. But what kind of marathon specific workouts did you do? Volume repeats of 1-3 miles. Long tempos in the 8-16 range @ GMP. Adding in a mid-week medium long run. Long runs in the 22-24 mile range that aren't 1/2 of your mileage. That's the sort of stuff that will get you strong.

I agree that maybe gels every 5 miles instead of 6 might help but there aren't any short cuts in the marathon.

Just one other thing I don't see mentioned previously... how was the weather/course over the last three miles? Any slight changes in the last three miles (wind/hills/less shade/temperature spike)?

you had me at meat tornado wrote:

Just one other thing I don't see mentioned previously... how was the weather/course over the last three miles? Any slight changes in the last three miles (wind/hills/less shade/temperature spike)?

50 at the start and low 70s at the finish line. No noticeable wind most of the time.

Thinking back over how I ran, it is likely I pushed it too hard from miles 16-20. I felt great and was running 15-30 sec/mile under goal pace for much of it. At the time, I was sure I’d be able to maintain it all the way. My goal pace was mostly a guess from interval work mixed with BQ wishes, and while running it seemed like I was more fit than the goal I’d set.

I appreciate all the feedback. I was expecting someone to say that not taking salt tablets was a big part of the problem.

Disko Eric wrote:

Well a bonk specifically refers to a depletion of gylcogen. So that was easy. Next question?

This.

The only way to avoid the bonk is to increase the % of energy you get from fat.

Running at a lower % of max VO2 will allow you to burn less glycogen. Either slow down at your current fitness, or develop a better running economy & aerobic capacity.

There is also a study (can't find the link anymore) where avoiding carbs from 2-3 hours before racing and 45 minutes into racing will cause you to burn 10-15% more fat. You will feel worse in the first half of the race, but should avoid the bonk. If you search the literature there are many more articles on taking carbs during this period to try and tap into a higher % of gylcogen in races under 2 hours.

Also, check out the carb supercompensation strategy. A 3 day dietary carb restriction, followed by 2-3 days of carb loading will allow the muscles to store a significantly greater amount glycogen than normal. Be careful with this one as the body will feel awful during the carb fasted state.

You did everything right. Maybe it was just the heat affecting you.

I wouldn't be surprised if you'd do better in your second marathon with identical preparation.

SprintDude wrote:

The only way to avoid the bonk is to increase the % of energy you get from fat.

'only way'?

No. How about consume more energy.

This way is both more practical and a greater increase in performance.

SprintDude wrote:

There is also a study (can't find the link anymore) where avoiding carbs from 2-3 hours before racing and 45 minutes into racing will cause you to burn 10-15% more fat.

Sure, but this also has the effect of decreasing your performance since fat does not produce energy as efficiently as glycogen.

SprintDude wrote:

You will feel worse in the first half of the race, but should avoid the bonk.

This scenario only works if you are running much slower than your race pace(which requires carbs).

anonymoose wrote:

More gels. A gel takes ~15 mins to kick in so one every 45 is probably not enough energy in for you. Especially if you are just consuming water. Assuming they are 100 cals each, that is only 300 over the course of a marathon which if you are pushing yourself is not enough.

+1

and Great job on the 3:10.

Impressive for your first M on 40mpw. I don't think you need more mileage.

Maybe go crush a 5k,10K,or1/2M sometime soon for a confidence boost!

ViperDom wrote:

SprintDude wrote:

The only way to avoid the bonk is to increase the % of energy you get from fat.

Running at a lower % of max VO2 will allow you to burn less glycogen. Either slow down at your current fitness, or develop a better running economy & aerobic capacity.

'only way'?

No. How about consume more energy.

This way is both more practical and a greater increase in performance.

Consuming carbohydrates during a marathon does seem to have a positive effect. You will increase availability of glucose in the blood, but the overall contribution is low for a serious marathoner trying to compete at >75% VO2 max for 2.5 - 3 hours. Gylcogen stores cannot be restored during the race. It takes 6 hours to turn sugar to glycogen under rested conditions.

Ingesting carbohydrates during the race may spare liver glycogen, but it has been found to have no effect on muscle glycogen sparing. Bottom line the bonk cannot be avoiding by in-race fueling.

The timing of the carb fueling does effect the % of energy produced from fat at the start of the race. The dietary manipulation I listed earlier can increase the amount of glycogen you have at the end of the race. You can also manipulate the reserves by going out more conservatively the first half of the race and aiming for a negative split.

Summary - Load carbs with a supercompensation strategy leading up to the race, Pre-race (inside of 3 hours out) carb loading does not add to glycogen stores, don't start in-race carb ingestion too early, do ingest carbs after 45min throughout the remainder of the race.

I had almost the exact same situation. I am 45, this was my 3rd, and fastest marathon. I ran 3:11:40, and started feeling off at 16, but didn't slow down until mile 24. I was shooting for 3:10, and lost 1:40 pretty evenly in the last 3 miles. I felt exactly as you described. My HR shot way up, my calves hurt, and it took all I had to keep going. I had a a normal pasta dinner the night before, about 400 calorie breakfast of PB toast, and consumed 4 gels along way. at 6, 12, 17 and around 21.

I had run a 1:25 half 3 weeks earlier, so I think I can do a little better in the marathon.

I had a very organized, training block that maxed out around 55-60MPW. I think for me too eek any more time out, I need to just run more. For a hobby jogger with average genetic ability like myself, I don't think a good performance can really be had without a bigger, deeper base. Im hoping 70mpw does the trick. I think to get there I will also need to really makes sure my longer runs don't go at too high of a pace so I can be recovered for the quality workouts.

Very few people get through their first marathon without crashing and burning the last few miles. And if you try to keep improving your time and break through time barriers, you will have more bonks in your future. I ran 16 marathons and really can only claim six as being solid races where I was able to finish strong without losing any time the last few miles.

They key to avoiding a bonk is balancing your preparation with your race expectations. If you are not doing a lot of 20+ milers and run a relatively low mileage training plan, you need to take any sort of marathon predicting workouts or races with a grain of salt. Yassos, half marathons, etc. do not tell you whether you are ready to get through mi 20-26. A better predictor is how well you are feeling on 20+ milers and how well you recover from those runs.

Also, to get through the wall, you do need to practice getting up as close to the wall as you can in workouts without going all in like a race. Long runs with marathon pace the last few miles or long intervals at MP with a moderate pace on rest intervals are key to getting your body ready to be able to maintain MP when you are running out of gas. It is a combination of being able to sustain a high heart rate and breathing cadence and being able to keep your legs moving when your body switched from muscle glycogen to fat for fuel.

I just finished the OKC Marathon and for the 1st time out of 7th marathon ran a - split and didn't even get those little cramps at all.

Some things that I think helped were for me, I took a gel every 4 miles up to mile 20 ( I am 5'9 175 lbs so a bit heavier than most 'competetive' runners. I also took a salt-mineral pill at hour 1 and 2. Took water or powerade every mile regardless if thirsty or not. I also ran in the next% for the first time so maybe the shoes helped too with not feeling too tired. I had my last mile about 30 seconds faster than my overall average pace,

One other thing is you said you ate pasta the night before, I started carb loading slightly Weds and then started eating a lot Thursday through Saturday to the point I was constantly full all day, I really think for me that main thing was the 3-4 day carb load.

Run your long run duration the time you are targeting.

Example: 3 hour goal ‘thon

Long run training: 3 hour run

To prevent staleness and getting too beat up during training do a 3 hour long run once every 3 weeks.

Week 1: 3 hour long run with last hour at goal pace

Week 2: 2 hour long run with last hour at goal pace

Week 3: 90 min progression long run- 30 min easy, 30 min goal pace, 30 min tempo

Repeat the 3 week cycle