Damsted C, et al. - In this prospective cohort study of 261 healthy (noninjured) runners over a period of 14 weeks, researchers examined the association between a change in weekly running distance and running-related injury (RRI). Further, they investigated whether the running schedule the runner follows modifies this association. Runners who increased their weekly running distances by 20% to 60% had significantly more injuries during the 21 days into the study period compared to those who increased their distances by less than 20%.