title: Frontal plane instability following rapid voluntary stepping: effects of age and a concurrent cognitive task.
abstract: BACKGROUND
  Quick step execution may prevent falls when balance is lost. Lateral steps often emerge as a consequence of frontal plane instability arising after the first rapid step. In this study, we suggest a new analysis, focusing on the variability of the frontal plane fluctuations of center of pressure (CoP), that is, mediolateral instability, and their changes over time during and immediately following rapid voluntary stepping in older and younger adults in single- and dual-task conditions. This may be useful in understanding age-related alterations in the locomotor control system.
  
  
  METHODS
  Seventeen older adults, who live independently in the community, and 16 younger adults performed rapid forward voluntary stepping under single- and dual-task conditions. The average mediolateral CoP fluctuations, that is, the average distance the CoP travels from side to side in the frontal plane over time, standard deviation, and the coefficient of variation of mediolateral CoP fluctuation were extracted and calculated from CoP data during and immediately following rapid voluntary stepping using a force plate.
  
  
  RESULTS
  We found an age-related increase in the coefficient of variation that represents the variability of frontal plane fluctuations and no significant differences in the average and standard deviations of frontal plane fluctuations. Cognitive task had no influence on measures of frontal plane fluctuations in both age groups.
  
  
  CONCLUSIONS
  The study showed frontal plane instability during and immediately following rapid stepping in older persons. This may be a factor contributing to lateral balance loss and the large number of lateral falls seen in the older population.
authors.affiliation: PT, Schwartz Movement Analysis & Rehabilitation Laboratory, Physical Therapy Department, Recanati School for Community Health Professions, Ben-Gurion University of the Negev, P.O.B. 653 Beer-Sheva 84105, Israel. itzikm@bgumail.bgu.ac.il.
authors.forename: Ilan
authors.initials: I
authors.lastname: Kurz
authors.forename: Elinor
authors.initials: E
authors.lastname: Berezowski
authors.forename: Itshak
authors.initials: I
authors.lastname: Melzer
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance
keywords: Aging; Balance; Falls; Postural; Variability.; control