Study Shows That Heel Strikers are Injured More Frequently Than Forefoot Strikers

But in general, those runners who landed on their heels were considerably more likely to get hurt, often multiple times during a year.  -Does Foot Form Explain Running Injuries?

Does this mean that those of us who habitually heel-strike, as I do, should change our form? “If you’re not getting hurt,” Dr. Lieberman says, “then absolutely not. If it’s not broke, don’t fix it.”

MY COMMENT:  The article clearly warns runners not to attempt transition to forefoot striking too quickly, and remember, you have to wear  light weight racing flats or minimalist shoes (I'm not sure it's even possible to learn how to forfoot strike in normal training flats).  I'd also make it a point to practice your new running form on a soft surface. 

In a related abstract Foot strike patterns and collision forces in habitually barefoot versus shod runners, barefoot runners were found to generate smaller collision forces than runners wearing shoes, even on hard surfaces. 

                Sketchers GoRun Minimalist Running Shoe