Posted: 30/04/2013 at 12:47
Too much pace is the most likely issue.... if you run faster than a certain threshold, you start using 'fast-twitch' muscle fibres... which are inefficient with fuel.
But are taking food and water with you on the run. For many people, 15 miles is roughly the time when your food supply gets depleted... and you need to be taking on carbohydrates during the run.
Same thing with water. How are you hydrating?
What are you doing the day or two before the long runs?
Can you answer these.... people can be more specific with advice then.
If you can get up to 18 - 20 miles, I suspect you'll be OK on the day (though it won't be easy)... Remember that you're doing your long runs whilst tired.. but come Edinburgh, you'll have rested/tapered... and will be feeling stronger.
I have been trying to follow the Hal Higdon novice plan. On my shorter runs I go at a 10min.mil pace and longer runs about 11min/mile but think that as the miles creap up this could be too quick for me as I drop down to a 12min/mile (which I know must seem really slow, I could probably walk faster). In total about 30 miles a week.
I bring a bottle of water with me and am using the cliff blocks, taking 2 every 45 minutes (long runs only). I sometimes bring walnuts to.I do a 5 mile run 2 days before my long run, then nothing the day before except trying to eat plenty of carbs and drink lots of water.On the morning of the run I have 3 eggs, 2 slices of toast, blueberries and yogurt, applejuice with concentrated beatroot jucie (30ml).