Just a comment on training, potential, enjoyment, etc. I have just finished the Liverpool half-marathon (only my 2nd half marathon), and was ecstatic to have done it in 2:08:30, 5 mins faster than my first half 18 months ago. The reason I started reading this thread was the starting question - should I have pushed myself harder? I managed to run up to and over the finish line quite fast (couldn't really call it a sprint though), so had a bit left in the tank - did I push myself hard enough? BUT, whenever I did push myself, I got the stitch (bane of my running and I think my biggest handicap) so had to slow down again. For me, the achievement lay as much in improving my time as the fact that I have trained consistently and as well as I can manage over the past 9 weeks. In a way that's more of a personal achievement coz it took a lot to make myself do it, and my life seems to have been a bit overtaken by it. I am really proud of myself for doing both the training and the run, so that's part of the reward for me too. In terms of genetics, etc, my body can't seem to handle it when I exercise more than about 4 days a week so I have to settle for quality not quantity. From reading about running, I thought that the improvements in times came from the speed/hill sessions as much as the long runs (if not more - the speed sessions increasing lactate threshold, training fast twitch fibres, etc????). But what you guys on this thread seem to be focussing on is weekly mileage. Surely if you want to run for a long time the long runs help this but they don't make you run much faster do they?