title: Variability of kinetic variables during gait in unilateral transtibial amputees.
abstract: BACKGROUND
  Prosthetic gait increases demands on stability. Some variability measures can be used to investigate the stability of movement for prosthetic feet.
  
  
  OBJECTIVE
  The purpose of this study was to determine the influence of the prosthetic foot on ground reaction force variability for transtibial amputee gait.
  
  
  METHODS
  Comparative analysis.
  
  
  METHODS
  Eleven male unilateral transtibial amputees participated in this study. Each subject walked at self-selected speed with both conventional (SACH) and energy storing (Sureflex) feet. Time and ground reaction force variables and their coefficients of variation were calculated for each foot type and limb.
  
  
  RESULTS
  Mediolateral force variables had high variability for all conditions. The Sureflex had a larger variability than the SACH foot for the braking peak (p < 0.05), which may have been caused by gait instability after the heel strike. There were significant differences between intact and prosthetic limbs in total loading (force impulses) with the SACH foot (p < 0.05).
  
  
  CONCLUSIONS
  The prosthetic foot and alignment issues related to the foot influence GRF variability. During the braking phase the SACH foot is characterized by higher variability in mediolateral direction and Sureflex by higher variability in anterior-posterior direction.
  
  
  CONCLUSIONS
  Differences in variability in ground reaction force variables can represent a person's stability. Observing variability can contribute to better understanding of critical events in gait cycle with the use of various prosthetic feet.
authors.affiliation: Faculty of Physical Culture, Palacky University, Olomouc, Czech Republic. zdenek.svoboda@upol.cz
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Svoboda
authors.forename: Miroslav
authors.initials: M
authors.lastname: Janura
authors.forename: Lee
authors.initials: L
authors.lastname: Cabell
authors.forename: Milan
authors.initials: M
authors.lastname: Elfmark
mesh_terms: D000328:Adult; D000674:Amputees; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology*; D006365:Heel / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D004856:Postural Balance / Q000502:physiology; D011474:Prosthesis Design; D013977:Tibia / Q000601:surgery*; D016474:Weight-Bearing / Q000502:physiology