title: High medial plantar pressures during barefoot running are associated with increased risk of ankle inversion injury in Royal Marine recruits.
abstract: BACKGROUND
  Ankle inversion injury is common in military populations but associated biomechanical risk factors are largely unknown. This prospective study examined the association between pressure and kinematic variables, and ankle inversion injury risk in Royal Marine (RM) recruits. It was hypothesised that a more medially concentrated pressure at the heel-off phase of stance, greater impulse and peak pressure at the first metatarsal head, greater peak rearfoot eversion angle and greater eversion excursion would be associated with ankle inversion injury.
  
  
  METHODS
  Data from 145 male, injury-free RM recruits were recorded in week-2 of a 32-week military training programme. Each recruit completed five running trials at 3.6 ms(-1), along a 2m pressure plate. Kinematic data were simultaneously recorded. Injuries sustained during the training programme were prospectively recorded.
  
  
  RESULTS
  Data from eleven recruits who had suffered an ankle inversion injury during RM training were compared with 20 uninjured controls. The injury group displayed a higher (P<0.05) peak first metatarsal pressure, peak metatarsal impulse and more medially concentrated pressure at heel-off than control recruits. There were no differences in kinematic variables between groups. The injury group had a lower body mass than controls (P<0.05).
  
  
  CONCLUSIONS
  The findings from this study support existing literature, providing evidence that high medial concentration of vertical forces when running are associated with increased ankle inversion injury risk. This may be due to the lateral ankle ligaments being less accustomed to loading, resulting in relatively weak lateral ligaments, or ligaments less able to deal with fatigue than those of the control group.
authors.affiliation: School of Sport and Health Sciences, University of Exeter, Exeter, UK. Electronic address: hmr204@exeter.ac.uk.
authors.forename: Hannah
authors.initials: H
authors.lastname: Rice
authors.forename: Michael
authors.initials: M
authors.lastname: Nunns
authors.forename: Carol
authors.initials: C
authors.lastname: House
authors.forename: Joanne
authors.initials: J
authors.lastname: Fallowfield
authors.forename: Adrian
authors.initials: A
authors.lastname: Allsopp
authors.forename: Sharon
authors.initials: S
authors.lastname: Dixon
mesh_terms: D000293:Adolescent; D016512:Ankle Injuries / Q000453:epidemiology*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D008889:Military Personnel; D011312:Pressure; D011446:Prospective Studies; D012307:Risk Factors; D012420:Running / Q000293:injuries / Q000502:physiology*; D012775:Shoes; D006113:United Kingdom; D055815:Young Adult
keywords: Ankle injury; Heel-off; Plantar pressure; Risk factors