Hi all, I'm training to do a half marathon in march. I think I'm on track, I regularly run 11.5 k in under an hour which I think is okay. This will be going up to 14k over the next few weeks. I went to a running shop at the weekend and when I spoke to him about my training which consists of running 11.5k at least twice a week, I suggested that I should mix it up a bit and do a 5k run instead of one of the longer runs. He said that I should do 5k a bit faster as this would help me. I did that today, my question is why would this help me? Surely I just need to keep running farther and farther more comfortably. Thanks Paul.