Why do I keep hitting the wall

I have ran seven marathons and in all but one I have hit the wall. I have trained very hard in all my marathons keeping up with training plans. My dream is to run a sub 3.15 but round about the twenty mile mark I start to blow. In my last marathon I ran 3 x 20 mile, 1 x 21 mile and a 22 mile training runs but in the race had to stop at 20 and walk the last 6. I have a pb half marathon 1.26 and a pb for 20 miles 2.22. If anyone has any good advice i would be very grateful as I am starting training for London.

Need a bit more info. How fast do you run your LSR in training? Do you take water, sweets, gels etc when running your race? Do you carb load before a marathon? What is your racing stratergy eg. go out hard? keep it at a steady pace? Did you do anything different in the one that you didn't hit the wall?

Hi Roadrunner In training I run my long runs 7 .30 - 7.45 pace. I do take on water on runs over 10 mile unless it is very hot. Only on runs of 20 miles or further would I take on gels. Race statergy is to run as many miles at sub 7.26 as possible and try and get myself ahead of time. In the race where I didnt hit the wall I had already ran a marathon 3 months before. No I dont carb load any different than I normaly eat but eat loads anyway cheers.

I do get very tired near the end of training but I do have a 3 week taper.

What Cougie said - if you're aiming at 7.20 min/miles in the race, then your long runs should be 8.20 to 9.00 min/miles.

Thanks for the advice guys I guess thats me slowing down. Millsy I did take gels during my last marathon every about 4 or 5 miles and I had normal breakfast cereal and toast about 3 hours before.

Sorry only getting back now. As everyone has said, slooowww down on your long runs. At least 1 minute slower than marathon pace is normally acceptable in long runs, see it as a reward for your hard work in other runs during the week. Its a chance to build up your stamina which is too low for a 3.15 marathon, as hitting the wall shows. Good luck!

Strap on a Heart Rate Monitor and make sure your training is aerobic.  I bonked in 6 marathons before I realized that running my long runs too fast, doing loads of intervals and tempo runs, plus hillwork and fartlek sessions all added up to my training being totally anaerobic.

After 4 months of low HR training I reached my goal time with a negative split...pity about the 3 years of wasted training...

Once again thank you for the advice. Teknik why is it so important for your training to be aerobic rather than anaerobic? what is the difference? Your old training plan is just like mine. Heart rate monitor might have to go on the christmas present list many thanks.

do you run long tempo runs at all?  and your longest run seems short, I'm a fan of the long run and always put in over 10, 20milers, including 6 at 23 or more and 1 full distance.  I agree in principle with the long run being slower, make sure it is 60-90sec a mile slower, but build in some faster sections, e.g. 20 east followed by 5 at marathon pace.  The caveat is that my longest run is normally about 3:15 and I wouldn't advise going much beyond that time wise.

G

I might attract some argument here, but the body has 2 main systems for producing energy - anaerobic, in which you burn glycogen, and aerobic, where you burn oxygen and fat.  The latter system is what you need to survive a marathon, as the body's store of glycogen will be exhausted if you run at an anaerobic pace for more than say 16 miles.

For me, the key to marathon training is to improve the pace at which you run aerobically. Scientists argue about where/if the body switches from aerobic to anaerobic production, but generally below 80% of maxHR is considered "aerobic".

I trained the bulk of my mileage at sub75% maxHR, at which heart rate my general pace improved by over 90 seconds.  In my last marathon I kept the HR at 80% for the first half, and while I drifted into the high 90's by the end, I had loads left in the tank, finishing the last mile at my half mara pace.

Harder is not better for mara training. Good luck !

I'd maybe pay a bit more attention to your carbing up as well.

I know you say you eat loads but the one time I tried to carb up I was amazed at just how much of a struggle it was to eat/drink the recommended grams of carbs per lbs of bodyweight.

It seems crazy to me to go to all of that effort in training to then not bother to count the amount of carbs you eat the last three days before the race.

Teknik, I think you are a little confused, anaeobic is without oxygen, i.e. the oxygen supply for come directly from the muscles, this system can be used for around 60s, and is the reason 400m is such a test.  All long distance running is concerned with the aerobic system, however this is where the balance between using glycogen and fat is important and indeed the long runs teach the body to burn a higher percentage of fat and to store more glycogen.  The banding for the HR percentages were a bit swiffy too, they seem to be for working range rather than max.

Ziggy, I a gree with your points about carbs and Ruth the nutritionist as part of the target 26.2 programme is very good and worth listening to for her podcast

sorry Choisty, the point I was trying to make was that the anaerobic system burns only glycogen (without, as you say, oxygen), whereas the aerobic system burns fat with oxygen, (and up 32 times less glycogen).

We use a mixture of both systems as we run - where the relative blend changes is debateable - I say 80%, you say 85%. The point is to get the OP to slow down...