One thing about this style of running though, is it safe to say you can't run as fast?
Just getting back to this thread. Thought I'd throw out some thoughts toward your post.
I think "fast" is a relative term. Here's why. The problem for most runners is getting to the starting line. There is a natural infatuation with "fast" or "speed" probably more to do with ego or acceptance from others which in my opinion keeps many from ever starting a journey toward fitness and running. If you have watched the video's I think one can safely conclude that if you get down some basic mechanics and begin to operate efficiently that the opportunity to get "fast" can certainly occur.
Let me share two quick stories.
A friend of mine recently started running. I had no idea that he was observing and following my running over the past few years. He got an inkling to get into shape and decided to give up drinking and smoking and he started running. I started following his running and was impressed to see him running a 10K (6.2 miles) at around an 8:20 pace. I noticed that he was running 2-3 times a week and always at pretty fast paces ... at least comparing them to myself (around an 8:45-9:15 pace). A few weeks he had done a 15K (9.3 miles) and then a half marathon (13.1 miles) a few weeks later ... all at around an 8:30 pace. I was more then impressed. Well, Gian had been struggling a bit with minor injuries in his legs and I had noticed he was complaining a bit about needing more time to recover but wanting to run more. He eventually had a nagging injury over a month period and was told by the Doctor to take some time off. One of the things he learned the hard way was that your lungs will develop and sustain your running load much quicker then the legs muscles, tendons and ligaments. Research proves that to be true. Gian admitted to me that he had been trying to reach my pace and achieve my running distances and in the process his body was tearing down. I have been running for about 3.5 years and in the process my legs have accumulated 1500, 2000 and 2000 miles over the past three years. So, when I head out for a 13.1 mile run at an 9:00 pace the reality is that I can run that faster if I like but more then that I'm using that run as a part of the process for my marathon training and my legs have developed to the point to handle that work load. I am just now, almost 4 years later ... working at some getting faster and lowering my marathon time to the 4 hour mark. My opinion is that most runners try to run too fast too quick.
The second story involves an experienced runner named Avi. He has actually run a marathon in 03:24:00 using the run/walk/run method. He has adapted the method so that he runs a mile and then walks 45 seconds and has been more then successful. In the past three years he became a Marathon Maniac (these guys run tons of marathons and there are different levels). His overall goal has been fitness and enjoying running. His wife started running half marathons with him and recently completed a marathon. One of the advantages of this method is the recovery feature that has been proven effective. His goal, much like mine, is to run for the love of running. Pace doesn't really matter to him. He enjoys being out there and he enjoys helping and bringing other people into the sport. Here is a link to one of his marathons he posted on RunKeeper.
http://runkeeper.com/user/Avimitz/activity/61982243
On the far right in the middle you will see his splits. Next to that you can see the words "intervals" and "miles". Here, Avi is using app (ISmoothRun) which he sets up to run a mile and then walk 45 seconds. You can see he is running anywhere from an 8:00-8:45 pace most miles and then walks for 45 seconds usually at a 13:45 pace. The great thing about this method is that Avi essentially runs 25 mile sprints. So, in his training, he uses his training plan to build the number of his one mile sprints.
After my marathon this Sunday I plan on switching completely to this type of running. I am 50 years old and overall I just want a healthy life and to run injury free. Chi Running has changed my running but I think I can actually run faster using this method. My wife used the Run/Walk/Run method to complete her marathon in 05:05:00. She could have run it faster but his goal wasn't time ... just to complete it. I currently use this method on my recovery runs. What is fascinating is to take these walk breaks (we have been running for 5 minutes then walk 30 seconds) and you still end up running as fast as you were doing with no breaks. Maybe it's the fact that you know you were walking so you pick up your pace a bit ... but as you run longer I know my legs are fresher and at the end of a long run if I want to run faster I know I can. The big selling point has been the speedy recovery time from a long run. Love that. FYI, my wife and I have been doing around a 10:00-10:15 pace for my recovery runs which are usually around a 10-11 miler. Here is the run ...
http://runkeeper.com/user/HeyBakerMark/activity/516904293