title: Strategies of stepping over obstacles: The effects of long-term exercise in older adults.
abstract: BACKGROUND
  Stepping over obstacles challenges stability and is a leading cause of falls in older adult populations. As walking and Tai Chi (TC) exercise have been suggested practices for older adults for fall prevention, the purpose of this study was to evaluate the obstacle-crossing strategies of long-term TC practitioners and exercise walkers.
  
  
  METHODS
  Thirty healthy older women (average age: 65.7 years) with either TC (n=15) experience (average experience: 8.2 years) or walking exercise (n=15; average experience: 8.8 years) participated in this study. We used three trial conditions: (1) normal walking, (2) crossing a 15cm (20% of leg length) obstacle, and (3) crossing a 23cm (30% of leg length) to assess obstacle-crossing strategy. Sagittal plane obstacle-crossing kinematic parameters and plantar pressures were used to evaluate the obstaclecrossing strategy. A MANOVA assessed differences between groups.
  
  
  RESULTS
  Individuals with a TC background crossed the obstacle significantly faster with a significantly longer step relative to the exercise walkers. Plantar pressure profiles between the two groups also differed. Exercise walkers showed greater plantar pressure in the forefoot; TC practitioners demonstrated greater medial heel plantar pressure during obstacle-crossing.
  
  
  CONCLUSIONS
  Our results suggest that obstacle-crossing strategies were affected by the type of longterm exercise. The strategies each group used had important attributes that affect stability during obstacle-crossing. Future studies are needed to understand how obstacle-crossing strategies are adopted and how exercise may influence the strategy used.
authors: Shandong Sports Science Center, Shandong, China; Shandong Institute of P.E. and Sports, Shandong, China.
authors: Cui
authors: C
authors: Zhang
authors: Dewei
authors: D
authors: Mao
authors: J L
authors: JL
authors: Riskowski
authors: Qipeng
authors: Q
authors: Song