Improvement of isokinetic knee extensor strength and reduction of postural sway in the elderly from long-term Tai Chi exercise

Ge Wu, Fang Zhao, Xinglong Zhou, Liu Wei

Research output: Contribution to journalArticlepeer-review

121 Scopus citations


Objectives: To compare isokinetic strength of leg muscles and foot center of pressure (COP) as a measure of sway between long-term Tai Chi practitioners and controls. Design: Cross-sectional study. Setting: Community setting. Participants: Twenty subjects in the Tai Chi group and 19 subjects in the control group (age, >55y). Intervention: Subjects in Tai Chi group had practiced Tai Chi for a minimum of 3 years. Main Outcome Measures: Concentric and eccentric strength of knee extensors and flexors at 60°/s and 120°/s and foot COP displacement during quiet stance with eyes open or closed. Results: People in the Tai Chi group had significantly higher knee extensor strength at all speeds tested (P<.013), and smaller foot COP excursions for both eyes open and eyes closed conditions (P<.05) than people in control group. No significant difference existed in knee flexors between the 2 groups (P<.713). The COP excursions correlated significantly with the eccentric strength of knee extensors (P<.07) but not with the concentric strength of knee extensors (P<. 14) or with the isokinetic strength of knee flexors at most of the speeds (P<.27). Conclusion: These findings support the hypothesis that the maintenance of eccentric strength of postural muscles in the lower extremities, which is beneficial for maintaining good postural stability, is helped through the long-term practice of Tai Chi.

Original languageEnglish (US)
Pages (from-to)1364-1369
Number of pages6
JournalArchives of Physical Medicine and Rehabilitation
Issue number10
StatePublished - Oct 2002
Externally publishedYes


  • Elderly
  • Knee
  • Muscle fibers, type II
  • Posture
  • Rehabilitation
  • Tai Chi

ASJC Scopus subject areas

  • Rehabilitation
  • Physical Therapy, Sports Therapy and Rehabilitation


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