title: Foot landing position during gait influences ground reaction forces.
abstract: OBJECTIVE
  The purpose of this study was to determine how foot landing position influenced the ground reaction forces of two coordinate systems during gait.
  
  
  METHODS
  Values of ground reaction forces components as expressed in two coordinate systems (room, foot) were used to compare ground reaction forces of different foot landing position.
  
  
  BACKGROUND
  Non-neutral foot landing position during gait could influence the mechanics of the whole body motion and/or the foot-ankle complex and produce different ground reaction forces patterns compared to a neutral foot landing position.
  
  
  METHODS
  Thirty females were assigned to a foot landing group: toe-out, toe-in or neutral. Each participant walked 10 trials across a force platform while three-dimensional motion was captured.
  
  
  RESULTS
  No differences were observed for vertical or anteroposterior ground reaction forces variables between groups for either coordinate system. For medio-lateral forces of both coordinate systems, toe-out participants exhibited greater first lateral and second medial maximum forces and exhibited greater impulses.
  
  
  CONCLUSIONS
  For toe-out participants, greater medio-lateral ground reaction forces of the room coordinate system indicate excessive forces are generated by toe-out participants that do not contribute to moving the participant forward. Furthermore, medio-lateral loading on the foot increases proportionally with the degree of toe-out.
  
  
  CONCLUSIONS
  Establishing norms for clinical populations requires understanding of factors that can influence ground reaction force (GRF). Foot landing position (FLP) only affects the medio-lateral forces. Excessive toe-out landing has been surmised to be related to injury. Greater forces acting medio-laterally to the foot's long axis may have a relevant effect on in/eversion loading of the foot.
authors.affiliation: Department of Exercise Sciences, Biomechanics Laboratory, University of Georgia, 300 River Road, Athens 30602-6554, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Simpson
authors.forename: P
authors.initials: P
authors.lastname: Jiang
mesh_terms: D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D013640:Tarsal Joints / Q000502:physiology