title: Center of pressure displacements during gait initiation in individuals with obesity.
abstract: BACKGROUND
  Obesity is known to affect balance and gait pattern increasing the risk of fall and injury as compared to the lean population. Such risk is particularly high during postural transitions. Gait initiation (GI) is a transient procedure between static upright posture and steady-state locomotion, which includes anticipatory antero-posterior and lateral movements. GI requires propulsion and balance control. The aim of this study was to characterise quantitatively the strategy of obese subjects during GI using parameters obtained by the Center of Pressure (CoP) track.
  
  
  METHODS
  20 obese individuals and 15 age-matched healthy subjects were tested using a force platform during the initiation trials. CoP plots were divided in different phases, which identified the anticipatory postural adjustments (APA1, APA2) and a movement phase (LOC). Duration, length and velocity of the CoP trace in these phases were calculated and compared.
  
  
  CONCLUSIONS
  The results show that the main characteristic of GI in obese participants is represented by a higher excursion in medio-lateral direction. This condition lead to longer APA length and duration, which are statistical significant during APA2 when compared to control subjects. We also found longer duration of APA1 and LOC phases. In terms of velocity, most of the phases were characterised by a reduced CoP velocity in antero-posterior direction and faster movement in medio-lateral direction as compared to the control group.
  
  
  CONCLUSIONS
  Our findings provide novel evidence in GI in obese subjects that may serve for developing exercise programs aimed at specifically improving balance in both the antero-posterior and lateral directions. Such programs together with weight management may be beneficial for improving stability during postural transitions and reducing risk of fall in this population.
authors.forename: Nicola
authors.initials: N
authors.lastname: Cau
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, p,za Leonardo da Vinci 32, 20133 Milan, Italy. veronica.cimolin@polimi.it.
authors.forename: Veronica
authors.initials: V
authors.lastname: Cimolin
authors.forename: Manuela
authors.initials: M
authors.lastname: Galli
authors.forename: Helmer
authors.initials: H
authors.lastname: Precilios
authors.forename: Elena
authors.initials: E
authors.lastname: Tacchini
authors.forename: Cristina
authors.initials: C
authors.lastname: Santovito
authors.forename: Paolo
authors.initials: P
authors.lastname: Capodaglio
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D004856:Postural Balance / Q000502:physiology*