Not to belabor the barefoot running approach on a swimming forum but this is something I'm trying, having never been a runner. I was impressed that the 10K Olympian leaders all used this style. I think this effortless, springy, distance running style is to (running) sprints as TI is to swimming sprints. And, like TI, speed eventually develops (or so I'm told). There are lots of youtube and other videos, books, etc. I found this stuff from Vivobarefoot helpful.