title: Stepping onto raised, laterally compliant structures: a biomechanical study of age and gender effects in healthy adults.
abstract: OBJECTIVE
  To investigate the effects of gender and age on the kinematics and kinetics associated with stepping onto, and balancing on, a raised structure with lateral compliance.
  
  
  BACKGROUND
  Falls from a stepladder tipping sideways are associated with considerable socioeconomic costs.
  
  
  METHODS
  Ten young women (YF) and 10 young men (YM), aged 23 to 29 years, and 10 older men (OM) aged 66 to 75 years were asked to step up onto one of two raised structures with increasing lateral compliance (C1 and C2), presented in sets of six trials separated by up to 12 rigid (C0) structure trials.
  
  
  RESULTS
  Structural compliance (C1 or C2) significantly affected step duration (p < .05) and lateral weight transfer velocity (p < .01). Significant age (p < .001) and gender (p < .05) differences were found in step duration and center of mass adjustments: With increasing structural compliance, participants required more time (YM: 15%; YF ranged from 33% to 45%; OM 35%-37%) to complete the step-up movement.
  
  
  CONCLUSIONS
  Increasing age and structural compliance were both associated with larger and longer-lasting structural oscillations that increase the risk for a lateral fall.
  
  
  CONCLUSIONS
  Older adults, in particular, should not hurry their movements on raised structures. Actual or potential applications of this research include additional safety instructions for ladder users and considerations of structural compliance for designers and authors of national or international standards for raised structures.
authors.affiliation: Biomechanics Research Laboratory, University of Michigan, Ann Arbor, Michigan, USA. bsyang@umich.edu
authors.forename: Bing-Shiang
authors.initials: BS
authors.lastname: Yang
authors.forename: James A
authors.initials: JA
authors.lastname: Ashton-Miller
mesh_terms: D000058:Accidental Falls; D000328:Adult; D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance; D012737:Sex Factors