Thanks for all the responses. I havent logged in for a few days so hadn't realised there had been so much discussion.

The main reason I ask is I've put a few routes together that I'd like to have go at later this year and just want to put some rough scheduling together to get an idea of what I might expect to be hitting certain splits in. Then I guess I can do some recces and test if those splits are likely to work or not.

So on Bill's suggestion, if I was to run 800m flat in say 5 mins, if I went and ran with that same intensity up a hill I should be doing about 100m in 5 mins? And if I was to run 250m flat in 3 minutes I would expect to run 100m down a steep hill in 3 mins?

Just to check I've understood that right? And then just make a few small adjustments on top of that based on terrain?

Thanks