What it takes to do 4km swim, 180km bike riding and 42km running race. All in one day. I talked with a friend who did it, and the most difficult he said, was to maintain the discipline to follow the training plan every week for 9 months. I've never ran a marathon, my longest bike ride was 125km, and my longest swim less than 1km. I have run once 20km. So, if I want to do the iron-man Triathlon I'll have to improve my swimming technique, run a marathon, and be at ease doing a 180km ride. If I get into this i'll aim to get my training in 3 months and not 9. This means that I'll have to train more, without injuries, without fatigue. I think I can quickly get to do a marathon, as I feel my endurance is pretty good. Once I ace that marathon I can do the swimming. The swimming is 90% technique, 4km is not a lot if I swim well and it's mostly