OK, so you've decided you are going to undertake an Ironman. You have watched a couple a motivational videos on YouTube, you have logged onto the site, entered your details, paid your fee, told everybody you know about it on Facebook and Twitter and have undertaken a sponsorship drive for the charity of your choice. Life is good and you feel good about it.At some point the enormity of what you have signed up for will hit you. It could be when you...