Hitting the wall during marathon training

Hello,

I was wondering if anyone could offer some marathon training advice. I ran 32km today (Monday) and at around the 30km mark I "hit the wall" (muscle glycogen depletion, not low blood sugar). I suspect this was caused by insufficent recovery time following my 38km run on Friday and hard 22km run on Sunday.

My suspicion is that it would not have been worth pushing on further during my 32km run - too dangerous etc - am I right? 

Are you sticking to a plan ?  Running over 20 miles with two days in between is pretty hard core and I've not seen that on any plans.

Most plans have the 20+ milers 2 weeks apart ? 

Have you been taking on any energy food/drink on these runs ?

And I think you're right - not much point in pushing on when you've blown. 

When is the marathon and are you used to these kinds of distances ?

I'm sorry for asking, but are you being serious?  First, I have to check, when you clarify that it was muscle glycogen depletion, are you stating that your blood sugar level was fine?  You ran out of glycogen, but your blood sugar wasn't low?  Also, are you certain that you didn't edge into liver glycogen depletion??  Did your lactate shuttle get stuck at the platform?

Second, did you run 38km on Friday?  Why?

Third, what is a "hard" 22k?  Did you race a half-marathon?  Then you followed up the next day by running 32k?  And from the sounds of it you only ran this because you decided not to push on further, is that correct?

Too dangerous?  No, it's not too dangerous to continue running once you've hit the wall.  You'll run at the limit of your fat-burning pace, and tbh the average human has enough fat for many many more miles.  Recovery from complete glycogen depletion can take days if you sit on your ass doing nothing, and weeks if you continue to train, with all that training being below par for hard sessions, though on par for the purer aerobic work.  No, the danger is continuing to train as you are, unless you're hiding a huge amount of experience and expertise from the forum which didn't manage to come across in your post.

When is your marathon, what's your training plan, and what's your background?

Thank you for your replies. I am running this as part of a programme, but owing to work commitments there are occasions when I have to place difficult workouts closer together than would otherwise be ideal. This was one such occasion: the two should have been a week apart rather than two days apart. Perhaps, though, it would be better to skip one such workout altogether?

Cougie: I took on 500ml of Lucozade and 250ml of water; the marathon is on 21 October (Amsterdam) and I am aiming for 2-50; I average 110-150km a week and am used to these distances (but not in such proximity, QED).

Ratzer: Yes I am being serious; I am pretty sure it was muscle glycogen depletion because I felt fine mentally (I certainly wouldn't consider continuing to run if I were feeling faint, disoriented or dizzy), but don't know either way on the liver question; I ran 38km on the Friday as part of the Advanced Marathon programme in Pfetzinger and Douglas's book (if you read it, you'll see I'm not following it 100% - the two runs should have been 39km and 32km); the "hard" 22km was 11km at half marathon pace and 11km at LSR pace).

Yes, it is better to skip the workout altogether in this case.  The reason that long and hard sessions have breaks is for recovery.  Whilst recovery on its own won't get you through a marathon, it is the most important part of a balanced training plan.  If you don't recover you are taking the route to overtraining and injury.

If you don't follow a plan 100% you had better know what you are doing and why you are doing it.  P&D is excellent, and the experience and thought that has gone into their plans is huge.  From your aim of 2-50 you must be either experienced at the distance, or good at the lower distances, so I am surprised still at your questions if you are an experienced marathon runner, and surprised that you would manipulate a P&D plan in such a way!  However, your intake of liquids is fairly high for a 32k training run if you started out well hydrated.  Also if you regularly take half a litre of lucozade, then the bonking was entirely due to your lack of recovery from the previous runs.  (Don't mix up low blood sugar with hypoglycaemia - unless you are diabetic you are unlikely to experience the symptoms you mention as you would effectively 'shut down' first in a similar situation and be unable to continue.  Low blood sugar is simply all 'free' blood sugar used up.  Past the wall your body maintains it by burning fat.)

I'm guessing you're a young runner with great lower distance times going for his first marathon.  Am I miles out?

Thank you, that's extremely helpful. Yes, I'm new to the marathon but pretty quick over shorter distances. Which explains the intense training regime but novice questions, as you suspected. 

Thanks again.

Then a word of advice.  Don't try to 'convert' your first marathon.  I have no idea what your lower distance times are, but guessing your HM is sub-1:20.  Conversion of time upwards to a predicted time for the marathon using calculators such as MacMillan depends on experience at the marathon distance and a history of long aerobic training.  Your present weekly mileage suggests plenty of doubles / triples which would by nature be shorter and more intense, even at 'easy' pace.  To predict a 2:50 for a first marathon I would hope you have a (sub-)1:15 HM.  Your leg strength and speed will actually work against you as you overdo the first 21-32k and you're not long-aerobically trained enough to cope with the last 10k at the same pace.

I'm just being risk averse.  Plenty of great shorter distance runners have messed up their first marathons.  Plenty have also had great debuts at the distance!  I hope you're in the latter group and you enjoy it.

Spot on - my HM time lies between 1:15 and 1:20. I'm not trying to "convert" my time though: I'm aiming for c.4:05 per km and am therefore doing my LSRs at around 4:35 to 4:40 per km. In other words, I picked a target and am trying to train accordingly rather than picking a target because McMillan reckons it's do-able.

I am of course aware that anything can happen over a marathon (let alone a debut marathon) so I shan't be too disappointed if I miss my target. That said, I'd be pretty disappointed if I missed 3:10...

Thanks again for the advice. Fingers crossed!