title: Ankle work and dynamic joint stiffness in high- compared to low-arched athletes during a barefoot running task.
abstract: High- (HA) and low-arched (LA) athletes have an exaggerated risk of injury. Ankle joint stiffness is a potential underlying mechanism for the greater rate of injury within these two functionally different groups. An alternative candidate mechanism of injury in HA and LA athletes pertains to the efficacy of the foot as a rigid lever during propulsion. The purpose of this study was to quantify the differences in ankle dynamic joint stiffness, and ankle braking work and ankle propulsive work during stance phase of running.
  
  
  METHODS
  Ten HA and ten LA athletes performed five barefoot running trials while ground reaction forces and three-dimensional kinematics were recorded. Ankle dynamic joint stiffness was calculated as the slope of the ankle joint moment-ankle joint angle plot during load attenuation. Ankle braking and propulsive work values were calculated for the stance phase.
  
  
  RESULTS
  HA athletes had significantly greater ankle dynamic joint stiffness and significantly smaller ankle net and propulsive work than LA athletes.
  
  
  CONCLUSIONS
  These data demonstrate that HA and LA athletes exhibit unique biomechanical patterns during running. These patterns may be related to lower extremity injury.
authors.affiliation: Department of Physical Therapy, Campbell University, Buies Creek, NC, USA. Electronic address: dpowell@campbell.edu.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Powell
authors.affiliation: Department of Physical Therapy, Virginia Commonwealth University, Richmond, VA, USA.
authors.forename: D S Blaise
authors.initials: DS
authors.lastname: Williams
authors.affiliation: Department of Physical Therapy, Campbell University, Buies Creek, NC, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Windsor
authors.affiliation: Doctor of Physical Therapy Division, Duke University, Durham, NC, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Butler
authors.affiliation: Department of Kinesiology, Recreation & Sport Studies, The University of Tennessee, Knoxville, TN, USA.
authors.forename: Songning
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001265:Athletic Injuries / Q000503:physiopathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D016059:Range of Motion, Articular / Q000502:physiology*; D012307:Risk Factors; D012420:Running / Q000293:injuries* / Q000502:physiology*; D055815:Young Adult
keywords: Ankle; Arch; Barefoot; Foot; Injury; Kinetics; Running