title: An evaluation of the heel strike transient in obese young adults during walking gait.
abstract: Obesity is considered a risk factor for knee osteoarthritis (OA) in part due to its influence on gait biomechanics. The heel strike transient (HST) is a characteristic of the ground reaction force that is indicative of a high rate of loading, but has not been evaluated in obese adults.
  
  
  
  To compare the incidence of HST in obese compared to normal weight adults.
  
  
  
  15 normal-weight (males=7, age=20.4±2.1years, body mass index=21.6±1.3kg/m(2)) and 15 obese (males=7, age=21.2±1.9years, body mass index=33.5±4.3kg/m(2)) young adults completed 10 walking trials at a standardized speed and 10 trials at a self-selected speed while ground reaction force data were sampled. HST incidence was evaluated using a dichotomous method previously identified in the literature, and compared between groups using χ(2) analyses.
  
  
  
  The number of individuals classified as possessing the HST differed between the obese and normal-weight groups (8/15 vs. 3/15, p=0.047). Evaluation of the standardized residuals indicated a significantly greater than expected incidence of the HST in the obese group when walking at a standardized speed.
  
  
  
  Our findings indicate that a greater proportion of obese compared to normal weight participants displayed a HST. The HST may provide a dichotomous method for identifying individuals with aberrant gait biomechanics.
authors.affiliation: Department of Kinesiology, California State University, Fullerton, Fullerton, CA, 92831, USA. Electronic address: dpamukoff@fullerton.edu.
authors.forename: Derek N
authors.initials: DN
authors.lastname: Pamukoff
authors.affiliation: Department of Kinesiology, California State University, Fullerton, Fullerton, CA, 92831, USA.
authors.forename: Robert I
authors.initials: RI
authors.lastname: Dudley
authors.affiliation: Department of Kinesiology, California State University, Fullerton, Fullerton, CA, 92831, USA.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Vakula
authors.affiliation: Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Curriculum in Human Movement Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Orthopedics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
authors.forename: J Troy
authors.initials: JT
authors.lastname: Blackburn
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006365:Heel; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000209:etiology; D012307:Risk Factors; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Ground reaction force; Knee; Loading rate; Obesity; Osteoarthritis