This thread is confusing me just a wee bit. What about someone like me, who is wanting to do a duathlon (or two or three or more)...am I doing two exercises that actually harm one another? Everything you're saying insinuates that running is harmful to cycling muscles. What do I do if those two exercises are the only ones in the race?

Then I think, triathletes do the same and add a third. And, they do so wonderfully.

So, I'm a bit confused. Please clear this up for my novice self. Thanks.