title: Multi-segment foot kinematics and ground reaction forces during gait of individuals with plantar fasciitis.
abstract: BACKGROUND
  Clinically, plantar fasciitis (PF) is believed to be a result and/or prolonged by overpronation and excessive loading, but there is little biomechanical data to support this assertion. The purpose of this study was to determine the differences between healthy individuals and those with PF in (1) rearfoot motion, (2) medial forefoot motion, (3) first metatarsal phalangeal joint (FMPJ) motion, and (4) ground reaction forces (GRF).
  
  
  METHODS
  We recruited healthy (n=22) and chronic PF individuals (n=22, symptomatic over three months) of similar age, height, weight, and foot shape (p>0.05). Retro-reflective skin markers were fixed according to a multi-segment foot and shank model. Ground reaction forces and three dimensional kinematics of the shank, rearfoot, medial forefoot, and hallux segment were captured as individuals walked at 1.35 ms(-1).
  
  
  RESULTS
  Despite similarities in foot anthropometrics, when compared to healthy individuals, individuals with PF exhibited significantly (p<0.05) (1) greater total rearfoot eversion, (2) greater forefoot plantar flexion at initial contact, (3) greater total sagittal plane forefoot motion, (4) greater maximum FMPJ dorsiflexion, and (5) decreased vertical GRF during propulsion.
  
  
  CONCLUSIONS
  These data suggest that compared to healthy individuals, individuals with PF exhibit significant differences in foot kinematics and kinetics. Consistent with the theoretical injury mechanisms of PF, we found these individuals to have greater total rearfoot eversion and peak FMPJ dorsiflexion, which may put undue loads on the plantar fascia. Meanwhile, increased medial forefoot plantar flexion at initial contact and decreased propulsive GRF are suggestive of compensatory responses, perhaps to manage pain.
authors.affiliation: Biomechanics Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA 01003, USA. Electronic address: ryan.chang.umass@gmail.com.
authors.forename: Ryan
authors.initials: R
authors.lastname: Chang
authors.affiliation: Biomechanics Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA 01003, USA; New Balance Sports Research Laboratory, Lawrence, MA 01843, USA.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Rodrigues
authors.affiliation: Motor Control Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
authors.forename: Richard E A
authors.initials: RE
authors.lastname: Van Emmerik
authors.affiliation: Biomechanics Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Hamill
mesh_terms: D000328:Adult; D000886:Anthropometry; D001696:Biomechanical Phenomena; D036981:Fasciitis, Plantar / Q000503:physiopathology*; D005260:Female; D005528:Foot / Q000502:physiology*; D033023:Foot Joints / Q000502:physiology; D005545:Forefoot, Human / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000502:physiology; D007700:Kinetics; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009989:Orthotic Devices; D012189:Retrospective Studies; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Forefoot; Kinetics; Medial longitudinal arch; Overuse injuries; Rearfoot