Harvard University researchers lead by Dr. Adam Daoud compared runners who forefoot strike compared to those who rear foot strike (or land more on their heels). Their sample included collegiate cross country runners.
They found that seven out of 10 used a rear foot strike. Approximately three out of four suffered from some type of moderate to more serious injury over the course of a year but those who typically rear foot strike had nearly two times the rate of repetitive stress injuries than those who tended to forefoot strike. While the researchers did not know the cause of this difference, they suggest further research into comparisons of the ground reaction force during rear foot versus forefoot strike.https://www.people.fas.harvard.edu/~skeleton/pdfs/2012b.pdf