I find that list very, very suspect... For starters, the people who aim to get sub 2:30 times and win the race are not the vast majority of marathon runners who are out there to push themselves personally and have fun. I've run two marathons, the Big Sur International Marathon and the San Francisco Marathon, without soiling myself or feeling confused. I felt elated, actually, thanks to the nice endorphin kick and the charge in the air from a few thousand athletes. There was also a sense of exploration as I had never run those routes before and there was a lot to see.
I was, however, injured but have since learned the reason why. The vast majority of modern runners have terrible, terrible running form. And pretty much everyone has terrible walking form. That's because we've been wearing clunky Western shoes ever since we were little babies that robbed our body of the very thorough biofeedback system in our feet and eliminated much of our natural shock absorption. The soles of your feet are so sensitive so that they can tell you what kind of surface you are running on and prepare your body for every step you take, including adjusting for terrain issues. Our bodies need to feel the ground beneath them but because we bind our feet in so much padding they can't feel so we literally slam our foot onto the ground trying to make contact.
Then our shoes prevent natural running form. Rather than land on the balls of our feet and let our joints bend and absorb the shock we are taught to slam our heels into the ground and 'roll' forward to push off. Pounding your heel into the ground transfers all of that energy straight to your knee, which then absorbs the shock, and deteriorates it.
There's a few great websites and articles on the issue but if you really want to know the difference go for a walk without your shoes on. And not just on grass or sand. Your ancestors walked and ran barefoot on all sorts of unforgiving terrain just as rough and hard as asphalt and concrete and you should too. Just go for a walk and see if your usual walking form works for you. Try running a very short distance if you feel brave.
Your body will naturally adjust your walking and running form, as well as anything else you do, to eliminate injury and strengthen itself if you allow it to do so.
I would also like to say that Phidippides, the first marathon runner, didn't die from running 26.2 miles. He died froming running 140 miles to Sparta, then running back, participating in the march to Marathon and the grueling battle there, and then ran the 26.2 miles to Athens.
