I agree. You....AGREE with me? Stop the presses. But seriously: I was also thinking about runners. The reason they push their chests out is because in a race, you need to break a plane (one that happens to be about equal to the height of your chest), not reach down and touch something. They are trying to go as fast as possible, by running through the finish line, while at the same time putting the part of their body that needs to be furthest out, furthest out. When a baserunner is heading toward first base, they should also run through the base, putting the part of their body that needs to be furthest out, furthest out. In a race, it's your chest, but in baseball, it's your foot. The reason they push their chests out is because they want to get the body ahead of the feet. Any part of your body crossing the plane wins the race. In baseball, it doesn't matter whether it's your foot, hand, or pinky finger, so long as something touches the base. Friction is less relevant at first, because ideally the way you would dive is so that at the instant you hit the ground, your hand touches the bag. The friction should all occur as you slide past the bag. I'm not advocating that a 6ft player dive 9ft before the bag and let momentum get him the rest of the way. I'm advocating that with your arm outstretched, above your head, if you're 7ft from foot to fingertips, that you dive as close to precisely that distance as possible. When you run out of the batters box, if you stay on your feet the whole way, your feet have to run 90ft. I presume no argument there. If you dive at first base, your feet only had to travel 83 ft (presuming the 7ft foot to fingertip measurement). The rest of that distance is covered by the height of the person and outstretched arms. This distance can actually be a little greater if your dive allows you travel a foot or two before touching the ground. Running 83ft is going to be faster than running 90ft. I really wish Mythbusters had done this experiment right.