ChiRunning is not based on the biomechanics of distance running. In fact there is no front end mechanics in chi running, which is key to successful competitive running(running agaist theclock). A few years I met Danny at an expo and asked him about why there is no front end mechanics in his book. He responded with their are no front end mechanics in distance running. I then open a Running Times to page where a worldclas field was contesting a 10K race. I pointed to the beautiful front end mechanics of these runner. Danny reply that is not a distance race. I say it is a 10K race. He reply anything shorter than a marathon is not a distance race. I will give Danny credited for getting people off their heels and landing under their center of gravity, but there is so much more to running mechanics. I have been working on this for 28 years and still have so much to learn. As for Danny he spend way too little years studying biomechanics and way too many years selling books, certifications, and promonting himself.