Perception of 'effort put in' it is something i dwell on a lot. When i could run a race properly i was a master at being in oxygen debt coming downhill, which gives you a different idea of what real pain is and reminds you how hard you can actually push it in other areas. Some of the interval sessions i used to do if i didn't bother with a race would cripple me now. Learning to turn it up to 11 is something i used to focus on a lot, the more you do it the easier it gets.