title: The duration and plantar pressure distribution during one-leg stance in Tai Chi exercise.
abstract: BACKGROUND
  Tai Chi exercise improved the balance control and muscle strength of the lower extremities. The aim of this study is to quantify the one-leg stance duration and plantar pressure distribution during the one-leg stance in Tai Chi and to try to elaborate on its probable effects on the ability to balance on one leg.
  
  
  METHODS
  Sixteen experienced Tai Chi practitioners participated in this study. The Novel Pedar-X insole system was used to record the plantar forces during the execution of a set of 42-form Tai Chi movements and during normal walking. The one-leg stance duration and plantar pressure distribution during the one-leg stance were analyzed.
  
  
  RESULTS
  In Tai Chi exercise, the total duration spent in the one-leg stance was less (p<0.05), the duration of each one-leg stance was longer (p<0.01) and the medial-lateral displacement of the centre of pressure was greater (p<0.05) than during normal walking. The peak pressure and pressure-time integral of the second and third metatarsal heads and the fourth and fifth metatarsal heads were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in normal walking, whereas the peak pressure and pressure-time integral of the first metatarsal head and the great toe were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in Tai Chi exercise.
  
  
  CONCLUSIONS
  The longer duration of each one-leg stance and the plantar pressure distribution characteristics during the one-leg stance in Tai Chi exercise may be associated with an improved ability to balance on one leg. The findings may provide useful information toward the development of strengthening programs, strategies for the prevention of falls, and the promotion of a physically active lifestyle.
authors.affiliation: Department of Sports Science and Physical Education, Chinese University of Hong Kong, Shandong Institute of Physical Education and Sports, China.
authors.forename: D W
authors.initials: DW
authors.lastname: Mao
authors.forename: J X
authors.initials: JX
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Hong
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005260:Female; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011312:Pressure; D026302:Tai Ji / Q000379:methods*; D013997:Time Factors; D016138:Walking / Q000502:physiology*