http://www.brandburg-labs.com/....can-i-be-good-at-phy
What are a couple of their undesirable? Well for one, NOT bending the knees enough; which results in a lot of impact at the ankles and knees. And two, developing the practice of landing on the heel, instead of the forefoot. This, basically stops the runner's forward momentum, and 'puts the brakes on.' Also, it sends a 'shock' through the entire leg, beginning from the heal, and sending it up through the knee. Not good, while a major explanation why runner's in padded, expensive shoes, claims McD