Hey guys, later this evening I have a 10 mile long run, I want to get in a fartlek that is relatively hard in the middle of it. I can't think of anything, all of the ideas I think of, I end up shooting down. Can you guys provide some ideas, I don't prefer anything in specific, like I don't prefer timed repetitions over distance, it really doesn't matter to me, I just want it to be a some what hard effort.
Just a heads up: I run 50-60 MPW, and my easy pace is usually 6:50-7:15. So you can give something more specific if possible.
Thanks all!