The biggest barrier we always have to overcome is the mental one.
Whether you want to build a V8 engine, build an 800m tall building, or run a marathon you will only be able to do it if you conquer the mind battle first. If you can believe it, then you can do it.
I have just finished reading two books that help me to let my mind expand:
Running to Extremes, by Lisa Tamati
Arthur Lydiard: Master Coach, by Arthur Lydiard and Garth Gilmour
Both these books broke the limits of what I had believed about running. Both these books took down the fence in my mind about my own running possibility. The fact is, that I don't know what my running possibility is because I haven't experimented enough.
What I do know is that my 'lofty goals' were very mediocre and were based on all that I could conceive at the time.
Now I have read of Lisa running for 37 hours in a race and Arthur Lydiard breaking 3hrs for the marathon at 62yrs old.
Now I have read of Lisa having such tremendous will to run, that she woke up running into trees during a 24hr race.
Now I have read that Arthur Lydiard experimented by running 250miles per week when he was younger.
Now I have read that, I realise that my thinking is limited because I haven't made any more progress towards the edge.
If I have one goal in 2013 (apart from my stated New Years Resolution: To eat more) then it is to go closer to the edge. Running is a tangible place that I can start. Now that I know that there is a lot more reserve in our body than I previously assumed, I know that only I can stop me achieving more. Actually, up until now it was only me stopping me, but I didn't know that.
I believe that success in one area flows to other areas precisely because you train your mind to expand and then work towards your new belief. For me running is a proving ground for my mind more than my body.