Originally Posted by Brian Ratliff

You have evidently never swam at the level that you bike or run. I don't get all this "swimming/running/biking" is easier than others. It's just what you are physically prepared and adapted to. All sports are as hard or easy as the amount of effort you put into it. That you think the swimming is easiest simply means that you didn't put much effort into it.

I swam competitively in high school. Swimming can be every bit as hard as running or cycling.

Also, another point coming from my former background of swimming: swimming is equal parts technique and fitness. What it does not share in common with running or cycling is that you cannot have the proper technique without the proper fitness. Since I've not been swimming for several years, I still retain the technique, but I cannot properly execute it for more than about 200 yards. I used to be doing over 7000 yards a day (broken up into interval sets, similar to what we do on our bikes), 4 days a week, in high school.

And lastly, many triathletes who excel at the bike part of the triathlon, eventually make there way into bike racing. They start by competing in TTs and then get into mass start racing. I've seen this progression with my own eyes a few times with the club I'm in. I have not seen many people going the other way. Cycling seems to be an obsession with cyclists. Triathletes seem to be obsessed with fitness in general; swimming, cycling, and running just being tools for the job.