It took us several minutes to catch up to him, as he never slackened his pace in the least bit. When we did we yelled at him "are you insane!" to which he replied, without slowing down or turning around, "don't break stride". His philosophy (though extreme in this situation) was that you set a pace and don't let anything slow you down.
Interestingly enough, I have found that this concept is ideal when it comes to walking, especially fast walking. My normal walking speed is between 4.5 mph and 5.0 mph, but I can never start off that fast and have to work my way up over a period of time - typically 10-15 minutes. But once I get there, I find the key to staying at that speed is to NEVER BREAK STRIDE. In fact, I get into a rhythm which turns into an auto-pilot kind of thing, where I don't even have to think about what I am doing, I just keep on truckin almost effortlessly. I transition from getting my body up to speed to taking in my surroundings, engaging in some deep thinking or just enjoying the music coming through my ZUNE.
However, if something gets in the way and I have to slow down - BAM - it screws everything up. Fatigue can set it, you start feeling a bit winded and now it takes your full concentration and willpower to get back up to speed. And if you don't do it pretty quick, it may not happen.
This is an important detail for those of you who have decided to setup a walking regimen. I used to be lucky to go 15 minutes non-stop now I can go on for 90 minutes without much effort. Of course, a big part of it is that I have worked up to that point over time, but I have also learned the power of DON'T BREAK STRIDE. Get your self up to a comfortable speed, focus on finding a smooth rhythm of movement between your stride, body position and arm swing. BTW - Your arms should swing at a natural rate as a result of your walking speed - don't try to artificially swing them as this will throw off your entire rhythm and pace.
It will take a while to figure out your ideal pace and body movement, but once you do, walking will be that much easier and a lot more effective.