I've watched that first video before... and i get a confused message, towards the start they have a message scrolling across the screen saying 'notice how he lands mainly on the ball of the foot and the midsection' or something to that effect, and saying about the benefits of that style of running/footstriking.
Yet a few minutes into the video where he starts to pick up the pace a little you can see him heelstriking? not HEAVILY heelstriking, but certainly not forefoot striking as before? and exactly the same happens later on when they show a guy running across grass "notice how his foot strikes the ground...." then soon after you can see him heelstriking?
The more I've read up on the matter the more I believe that you shouldn't worry much about your footstrike, there's really not a great deal between lightly heelstriking and forefoot striking, and you should just run how you are comfortable. As long as you're not heavily heelstriking or tip-toeing around your entire runs you should'nt have too much of a problem! Afterall, there's world champions who forefoot strike, world champs who heelstrike, and even those who strike with the midfoot - what does that suggest to you?
Happy running people
