Not true! I've found that both things compliment one another. My strength is starting to be respectable and I can run a half marathon without a problem.
@TA, that runner guy is so weak! I'm basically using the weights he's using
there is definetly a synergy between a healthy body capable of performing prolonged or intense bouts of cardiovascular activity and functionality. one makes the other better. a remarkable mechanism is the body. capable of so much but for the most part we dont attempt to build and utilize that functionality or strive to increase it.
like scorp mentioned david goggins. the guys a true machine. just decided one day he was going to do ultra marathons to raise money I think it was for the children of guys he worked with who lost their lives in war. having never run one before he ends up breaking the bones in his feet and came close to renal failure. now he's top of the food chain. what amazed me most abt his story was not just his going out and doing something that should have been impossible, but later on finding out he had a congenital defect in his heart that made it not function as well as a healthy one would. lol
I think you can have it all. be muscular. be able to perform prolonged bouts of cardio. be optimal. the question is how much time are you willing to give up in order to achieve it cause nothing good worth having comes without sacrifice and hard work. this is especially true in regards to your own performance.