Plantar pressure distribution during Tai Chi exercise

OBJECTIVES: To describe and quantify the plantar pressure distribution characteristics during Tai Chi exercise and to explain the beneficial effect of Tai Chi on balance control and muscle strength when compared with normal walking. DESIGN: Description and within-subject design. SETTING: A biomechanics laboratory. PARTICIPANTS: Sixteen experienced Tai Chi practitioners. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pressure-time integral, ground reaction force, and displacement of center of pressure (COP). RESULTS: During Tai Chi movements, the loading of the first metatarsal head and the great toe were significantly greater than in other regions (P<.05). The ground reaction forces varied between the Tai Chi movements and normal walking. Compared with normal walking, the locations of the COP in the Tai Chi movements were significantly more medial and posterior at initial contact (P<.05), and were significantly more medial and anterior at the end of contact with the ground (P<.05). The displacements of the COP were significantly wider (P<.05) in the mediolateral direction in the forward, backward, and sideways Tai Chi movements. The displacement was significantly larger (P<.05) in the anteroposterior direction in the forward movement. CONCLUSIONS: The plantar pressure characteristics of Tai Chi movements found in this study may be one of the important factors that Tai Chi exercise improves balance control and muscle strength.