title: Greater vertical impact loading in female runners with medically diagnosed injuries: a prospective investigation.
abstract: BACKGROUND
  Running has been critical to human survival. Therefore, the high rate of injuries experienced by modern day runners is puzzling. Landing on the heel, as most modern day shod runners do, results in a distinct vertical impact force that has been shown to be associated with running-related injuries. However, these injury studies were retrospective in nature and do not establish cause and effect.
  
  
  OBJECTIVE
  To determine whether runners with high impacts are at greater risk for developing medically diagnosed injuries.
  
  
  METHODS
  249 female runners underwent a gait analysis to measure vertical instantaneous loading rate, vertical average loading rate (VALR), vertical impact peak (VIP) and peak vertical force. Participants then recorded their mileage and any running-related injuries monthly in a web-based, database programme. Variables were first compared between the entire injured (INJ; n=144) and uninjured (n=105) groups. However, the focus of this study was on those injured runners seeking medical attention (n=103) and those who had never injured (n=21).
  
  
  RESULTS
  There were no differences between the entire group of injured and uninjured groups. However, all impact-related variables were higher in those with medically diagnosed injuries compared with those who had never been injured. (effect size (ES) 0.4-0.59). When VALR was >66.0 body weight (BW)/s, the odds of being DX_INJ were 2.72 (95% CI 1.0 to 7.4). Impact loading was associated with bony and soft-tissue injuries.
  
  
  CONCLUSIONS
  Vertical average loading rate was lower in female runners classified as 'never injured' compared with those who had been injured and sought medical attention.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Irene S
authors.initials: IS
authors.lastname: Davis
authors.affiliation: Department of Health and Nutritional Sciences, South Dakota State University, Brookings, South Dakota, USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Bowser
authors.affiliation: School of Sport and Exercise Science, University of Lincoln, Lincoln, Lincolnshire, UK.
authors.forename: David R
authors.identifier: http://orcid.org/0000-0002-5688-404X
authors.initials: DR
authors.lastname: Mullineaux
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000145:classification / Q000453:epidemiology*; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait; D006801:Humans; D012420:Running / Q000293:injuries*; D016474:Weight-Bearing; D055815:Young Adult
keywords: Biomechanics; Injuries; Overuse; Prospective