title: Forefoot angle at initial contact determines the amplitude of forefoot and rearfoot eversion during running.
abstract: BACKGROUND
  Clinically, foot structures are assessed intrinsically - relation of forefoot to rearfoot and rearfoot to leg. We have argued that, from a biomechanical perspective, the interaction of the foot with the ground may influence forces and torques that are propagated through the lower extremity. We proposed that a more appropriate measure is an extrinsic one that may predict the angle the foot makes with ground at contact. The purposes of this study were to determine if the proposed measure predicts contact angles of the forefoot and rearfoot and assess if the magnitude of those angles influences amplitude and duration of foot eversion during running.
  
  
  METHODS
  With the individual in prone, extrinsic clinical forefoot and rearfoot angles were measured relative to the caudal edge of the examination table. Participants ran over ground while frontal plane forefoot and rearfoot contact angles, forefoot and rearfoot eversion amplitude and duration were measured. Participants were grouped twice, once based on forefoot contact inversion angle (moderate<median and large>median) and once based on rearfoot contact inversion angle (moderate<median and large>median).
  
  
  RESULTS
  The forefoot and rearfoot extrinsic clinical angles predicted, respectively, the forefoot and rearfoot angles at ground contact. Large forefoot contact angles were associated with greater amplitudes (but not durations) of forefoot and rearfoot eversion during stance. Rearfoot contact angles, however, were associated with neither amplitudes nor durations of forefoot and rearfoot eversion.
  
  
  CONCLUSIONS
  Possible mechanisms for the increased risk of running injuries associated with large forefoot angles are discussed.
authors.affiliation: Department of Physical Therapy & Athletic Training, College of Health and Rehabilitation Sciences: Sargent College, Boston, MA, USA. Electronic address: gmm9@bu.edu.
authors.forename: Gail M
authors.initials: GM
authors.lastname: Monaghan
authors.affiliation: Department of Physical Therapy & Athletic Training, College of Health and Rehabilitation Sciences: Sargent College, Boston, MA, USA.
authors.forename: Wen-Hao
authors.initials: WH
authors.lastname: Hsu
authors.affiliation: Department of Physical Therapy & Athletic Training, College of Health and Rehabilitation Sciences: Sargent College, Boston, MA, USA.
authors.forename: Cara L
authors.initials: CL
authors.lastname: Lewis
authors.affiliation: Department of Physical Therapy & Athletic Training, College of Health and Rehabilitation Sciences: Sargent College, Boston, MA, USA.
authors.forename: Elliot
authors.initials: E
authors.lastname: Saltzman
authors.affiliation: Department of Kinesiology, University of Massachusetts, Amherst, MA, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Hamill
authors.affiliation: Department of Physical Therapy & Athletic Training, College of Health and Rehabilitation Sciences: Sargent College, Boston, MA, USA.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Holt
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005545:Forefoot, Human / Q000502:physiology*; D006365:Heel / Q000502:physiology*; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D009068:Movement; D011403:Pronation; D012420:Running / Q000502:physiology*; D055815:Young Adult
keywords: Forefoot inversion; Musculoskeletal injury; Pronation; Rearfoot inversion