So lovely to see so many new posters!
If you get a charity place with a minimum sponsorship they you have to pay the difference if you don't raise enough, hence why it's a big responsibility and a they don't fill up as quickly!
5k in 25 mins is pretty quick SinglePringle, I'd say your stopping is mind over legs personally. Perhaps slow it down slightly until you can complete the while 5k then increase speed again.
Oh no EATmum, I've no idea with injuries but I'd get to see someone who does or google
seriously though if you are sensible and can be sure where your pain is oh can quite often fine exercises to help.
vikkik888 I guess it depends how you want to do it. This may literally be a once in a lifetime chance. Do you want to do it this year and do ok or do it next year and do it as well as you can? If you have a time in mind and aren't going to make that I'd defer but if you just want to get round and have the experience then go for it this year :)