I have been running for 18 months and managed 3 halfs this year. I train 3 times a week including 1 long 1 speed and 1 hill.
All now goes well. I haved got down 2 50 mins for 10k and 1.30 for 10 miles. My problem is no matter how slow or quick I go if my long run goes over 10 miles I blow up. Any ideas or do I just need to go threw this by doing the longer distance more often?