title: Are clinical measures of foot posture and mobility associated with foot kinematics when walking?
abstract: BACKGROUND
  There is uncertainty as to which foot posture measures are the most valid in terms of predicting kinematics of the foot. The aim of this study was to investigate the associations of clinical measures of static foot posture and mobility with foot kinematics during barefoot walking.
  
  
  METHODS
  Foot posture and mobility were measured in 97 healthy adults (46 males, 51 females; mean age 24.4 ± 6.2 years). Foot posture was assessed using the 6-item Foot Posture Index (FPI), Arch Index (AI), Normalised Navicular Height (NNHt) and Normalised Dorsal Arch Height (DAH). Foot mobility was evaluated using the Foot Mobility Magnitude (FMM) measure. Following this, a five-segment foot model was used to measure tri-planar motion of the rearfoot, midfoot, medial forefoot, lateral forefoot and hallux. Peak and range of motion variables during load acceptance and midstance/propulsion phases of gait were extracted for all relative segment to segment motion calculations. Hierarchical regression analyses were conducted, adjusting for potential confounding variables.
  
  
  RESULTS
  The degree of variance in peak and range of motion kinematic variables that was independently explained by foot posture measures was as follows: FPI 5 to 22 %, NNHt 6 to 20 %, AI 7 to 13 %, DAH 6 to 8 %, and FMM 8 %. The FPI was retained as a significant predictor across the most number of kinematic variables. However, the amount of variance explained by the FPI for individual kinematic variables did not exceed other measures. Overall, static foot posture measures were more strongly associated with kinematic variables than foot mobility measures and explained more variation in peak variables compared to range of motion variables.
  
  
  CONCLUSIONS
  Foot posture measures can explain only a small amount of variation in foot kinematics. Static foot posture measures, and in particular the FPI, were more strongly associated with foot kinematics compared with foot mobility measures. These findings suggest that foot kinematics cannot be accurately inferred from clinical observations of foot posture alone.
authors.affiliation: Discipline of Podiatry, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia ; Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Buldt
authors.affiliation: Discipline of Podiatry, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia ; Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia.
authors.forename: George S
authors.initials: GS
authors.lastname: Murley
authors.affiliation: Institute of Sport, Exercise & Active Living, Victoria University, Footscray, Melbourne, VIC 8001 Australia.
authors.forename: Pazit
authors.initials: P
authors.lastname: Levinger
authors.affiliation: Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia.
authors.forename: Hylton B
authors.initials: HB
authors.lastname: Menz
authors.affiliation: School of Health Sciences, University of Salford, Salford, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Nester
authors.affiliation: Discipline of Podiatry, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia ; Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Melbourne, VIC 3086 Australia.
authors.forename: Karl B
authors.initials: KB
authors.lastname: Landorf