I set out on a 10k route knowing I would not be able to run all of it but had a plan to run about 6k then walk / run / jog the remainder. Things started ok as I set a steady pace for the first km, 2k & 3k were a good mix of up and down hill and much to my surprise I found 3k came up under 18 minutes which lead to think about a 5k PB the 4th k was reasonably level and the 5th k was slightly downhill for half then uphill again. The time was 27.40 including my first 1k under 5 minutes. I was absolutely staggered at the time.
I made a mistake at this point I stopped running to enjoy the moment and walked for a short while. When I started up again I could not get going so ended up walking again. Eventually I got going again and managed to run another 2.5k at an average of 6 minutes per K so not to bad.
When I reviewed it all I came to the conclusion I needed an energy boost at the 5 k point, not something I have needed previously but as I am now running harder I imagine I am using more energy which will need replacing.
I would be happy to hear from my more experience running friends out there with any suggestions.