title: Comparison of the static and dynamic balance performance in young, middle-aged, and elderly healthy people.
abstract: BACKGROUND
  Body sway increases with age. The purpose of this study was to obtain baseline data and the characteristics of balance performance in different age groups for balance strategy management.
  
  
  METHODS
  Healthy individuals (n = 107) were divided into young, middle-aged, and elderly groups, and assessed by computerized dynamic posturography (CDP) on a Smart Balance Master. The 6 subtests in the sensory organization tests (SOT) for the CDP were as follows: subtest 1, eyes open, fixed support platform; subtest 2, eyes closed, fixed platform; subtest 3, eyes open, fixed platform; subtest 4, eyes open, swaying platform; subtest 5, eyes closed, swaying platform; subtest 6, swaying visual surround, swaying platform. Motor balance control tests included the limit of stability (LOS) test at 75% of LOS in 8 directions and the left/right and forward/backward rhythmic weight shift (RWS) test.
  
  
  RESULTS
  In the SOT, the elderly group demonstrated significantly lower average stability and maximal stability scores in subtests 4-6. This group also demonstrated a relatively lower average percentage of ankle strategy in subtests 4-6. In the motor control tests, the elderly group demonstrated a significantly higher overall reactive time and lower overall directional control in the LOS test, lower on-axis velocity during the forward/backward and left/right motor control test and a lower average percentage of forward/backward directional control in the RWS test.
  
  
  CONCLUSIONS
  The elderly had a higher degree of postural imbalance and used hip strategy to a greater extent to maintain their balance, especially when standing on a swaying support surface in the absence of visual surround or with conflicted visual surround. The elderly required a longer reaction time and demonstrated lower directional control in balance performance.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan. meiyunliaw@cgmh.org.tw
authors.forename: Mei-Yun
authors.initials: MY
authors.lastname: Liaw
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Chen
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Pei
authors.forename: Chau-Peng
authors.initials: CP
authors.lastname: Leong
authors.forename: Yiu-Chung
authors.initials: YC
authors.lastname: Lau
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time