Psychology's role in Endurance Sport

I'm no sports psychologist and to be fair know very little about it but I'm adamant that a persons mental state plays as much if not more of a role than a persons fitness and general conditioning for endurance events.

To start with I know guys who are in better shape than I am but would no way even attempt a big endurance event. They know it's going to push them to hell and beyond and that's before your body has started to cramp up or hurt so much that it's begging for you to stop moving! I read somewhere that you as the person is both the solution and the problem. I think this is true, You've either got it or you haven't. If you haven't you don't even think about some silly challenge, but if you have got the state of mind then it's all you think about. When one things completed, achieved, not long after theres always need for something else. It's just the way it is.

I sometimes wonder why does one person of a similar fitness level to the next think something is impossible whilst the next will think it's totally possible?

Personally I just tell myself weeks out, this is going to hurt like hell but mentally I prepare myself for the pain and suffering and when it comes cope with it best I can, with just one rule don't stop moving unless it's absolutely got to a horrendous stage :) Every time I do a big endurance sport I mentally get stronger, I start thinking about how fast I could do something, or I wonder if I could do X or Y?

To sum it up I'm decent at running far, ok on the bike but none existent at swimming, I've never done a triathlon and haven't been in the pool for over 18months yet I've just gone and entered an Ironman. Granted I'm not doing it from scratch but it's out of my comfort zone so is hard, probably the most challenging event I've done to date.

Anyway that's 11 months away so once Xmas is out the way that will be the main goal. For now I've got three marathons in 3 days coming up along the coastal path which is going to be tough but physically I know I can do it as I did it last year. So know it changes to a mental challenge, how much can I push myself to finish as high up the leader board and improve on my 4th place last year? That's probably up to what sort of mental state I'm in, I'll have prepared myself mentally as well as physically by pushing myself to the limit in training, as strange as it sounds to just practicing suffering so that come race day I'm ready.

All in all as much as to do well in these events/challenges/races you have to be in fantastic physical shape, i'f your goal is just to finish something, regardless of how long it takes then if your mrntal state is good then theres no reason why you can't achieve something that you can only imagine possible at the moment.