title: An Investigation of Structure, Flexibility, and Function Variables that Discriminate Asymptomatic Foot Types.
abstract: It has been suggested that foot type considers not only foot structure (high, normal, low arch), but also function (overpronation, normal, oversupination) and flexibility (reduced, normal, excessive). Therefore, this study used canonical regression analyses to assess which variables of foot structure, function, and flexibility can accurately discriminate between clinical foot type classifications. The feet of 61 asymptomatic, healthy adults (18-77 years) were classified as cavus (N = 24), rectus (N = 54), or planus (N = 44) using standard clinical measures. Custom jigs assessed foot structure and flexibility. Foot function was assessed using an emed-x plantar pressure measuring device. Canonical regression analyses were applied separately to extract essential structure, flexibility, and function variables. A third canonical regression analysis was performed on the extracted variables to identify a combined model. The initial combined model included 30 extracted variables; however 5 terminal variables (malleolar valgus index, arch height index while sitting, first metatarsophalangeal joint laxity while standing, pressure-time integral and maximum contact area of medial arch) were able to correctly predict 80.7% of foot types. These remaining variables focused on specific foot characteristics (hindfoot alignment, arch height, midfoot mechanics, Windlass mechanism) that could be essential to discriminating foot type.
authors.affiliation: 1 Massey University.
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Shultz
authors.affiliation: 2 Temple University School of Podiatric Medicine.
authors.forename: Jinsup
authors.initials: J
authors.lastname: Song
authors.affiliation: 3 Hospital for Special Surgery.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Kraszewski
authors.affiliation: 3 Hospital for Special Surgery.|4 University of Massachusetts Amherst.
authors.forename: Jocelyn F
authors.initials: JF
authors.lastname: Hafer
authors.affiliation: 3 Hospital for Special Surgery.|5 New York University.
authors.forename: Smita
authors.initials: S
authors.lastname: Rao
authors.affiliation: 3 Hospital for Special Surgery.
authors.forename: Sherry
authors.initials: S
authors.lastname: Backus
authors.affiliation: 3 Hospital for Special Surgery.|6 Anglia Ruskin University.
authors.forename: Rajshree M
authors.initials: RM
authors.lastname: Hillstrom
authors.affiliation: 3 Hospital for Special Surgery.
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Hillstrom
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000886:Anthropometry; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D007593:Joint Instability; D008297:Male; D008875:Middle Aged; D011187:Posture; D011312:Pressure; D012044:Regression Analysis; D012189:Retrospective Studies; D055815:Young Adult
keywords: clinical biomechanics; kinematics; musculoskeletal