title: Instantaneous stiffness and hysteresis of dynamic elastic response prosthetic feet.
abstract: BACKGROUND
  Dynamic elastic response prosthetic feet are designed to mimic the functional characteristics of the native foot/ankle joint. Numerous designs of dynamic elastic response feet exist which make the prescription process difficult, especially because of the lack of empirical evidence describing the objective performance characteristics of the feet.
  
  
  OBJECTIVE
  To quantify the mechanical properties of available dynamic elastic response prosthetic feet, specifically the stiffness and hysteresis.
  
  
  METHODS
  Mechanical testing of dynamic elastic response prosthetic feet.
  
  
  METHODS
  Static Proof Testing in accordance with ISO 10328 was conducted on seven dynamic elastic response prosthetic feet. Load-displacement data were used to calculate the instantaneous stiffness in both the heel and forefoot regions, as well as hysteresis associated with each foot.
  
  
  RESULTS
  Heel stiffness was greater than forefoot stiffness for all feet. The heel of the glass composite prosthetic foot was stiffer than the carbon fiber feet and it exhibited less hysteresis. Two different carbon fiber feet had the stiffest forefoot regions.
  
  
  CONCLUSIONS
  Mechanical testing is a reproducible method that can be used to provide objective evidence about dynamic elastic response prosthetic foot performance and aid in the prescription process. Clinical relevance The quantitative stiffness and hysteresis data from this study can be used by prosthetists to aid the prescription process and make it more objective.
authors.affiliation: Mayo Clinic, Minnesota, MN, USA.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Webber
authors.affiliation: Mayo Clinic, Minnesota, MN, USA.
authors.forename: Kenton
authors.initials: K
authors.lastname: Kaufman
mesh_terms: D000674:Amputees / Q000534:rehabilitation*; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D019544:Equipment Failure Analysis / Q000379:methods*; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008422:Materials Testing; D011474:Prosthesis Design / Q000379:methods*; D017755:Prosthesis Fitting; D018570:Risk Assessment
keywords: Heel stiffness; energy; forefoot stiffness; prosthetists