title: [Differences in momentum development when standing up from a chair between elderly with and without frequent falls history].
abstract: BACKGROUND
  The momentum of the upper body (UB) during transfer sit-to-stand (STS) could be sensitive to the deterioration of dynamic postural control, and also the risk of falls. The aim of this study is to quantify the differences in the momentum development on UB during the STS in a sample of fall and no-fall elderly subjects. MATERIAL AND MEHODS: The sample consisted of twenty three voluntary elderly subjects (n=23), six elderly adults with antecedents of frequent falls (more than two within a year period) and seventeen without histories of frequent falls. Through a motion analysis system we registered the kinematics of UB during STS, from which we calculated the momentum of UB. The determined analysis variables were: the maximum values of the vertical (P(V)M) and horizontal (P(H)M) lineal momenta, the minimum (L(Max)) and maximum (L(Min)) values of the angular momentum and maximum trunk flexion (thetaM(UB)).
  
  
  RESULTS
  No difference was observed in P(H)M, L(Max) and L(Min) (P>0.05) between both groups. However, a significant difference was found for the variable P(V)M (P=0.03) and thetaM(UB) (P=0.03) between both groups.
  
  
  CONCLUSIONS
  We can conclude that, for the sample studied, the frequent fall condition relates to a smaller capacity to develop vertical momentum and increase flexion of the upper body.
authors: Laboratorio de Biomecánica y Control Motor, Universidad Santo Tomás, Santiago, Chile. rodrigoguzmanvenegas@gmail.com
authors: Rodrigo Antonio
authors: RA
authors: Guzmán
authors: Hugo Enrique
authors: HE
authors: Prado
authors: Helvio
authors: H
authors: Porcel Melián
authors: Benoit
authors: B
authors: Cordier
mesh_terms: D000058:Accidental Falls; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D011187:Posture