Knee biomechanics of selected knee-unfriendly movement elements in 42-form Tai Chi

The aim of this study was to examine ground reaction force (GRF) and knee biomechanical characteristics of certain knee-unfriendly Tai Chi movement elements, comparing them with slow walking, and examining the effects of pose height (low and high) of Tai Chi movement elements on the knee biomechanics. Seventeen participants performed three trials under eight conditions: slow walking, toe-touch pseudo-steps, and high- and low-pose lunges, pushdowns and kicks. Kinematic and GRF data were recorded simultaneously. Data were analysed using repeated measures analysis of variance (α = 0.05). Greater peak knee extension moments were found in all Tai Chi movement elements of both poses, except for high-pose kick, compared to slow walking. The peak knee extension moment was greater in the low-pose lunge, pushdown and kick than those of high-pose elements. The high-pose lunge also showed smaller peak knee abduction moment and knee adduction range of motion compared to the low-pose lunge. When designing Tai Chi exercises for knee osteoarthritis patients, it is recommended to modify lunge and avoid the Tai Chi movements that include pushdown and pseudo-step due to their high knee extension moments. A high-pose position would be more suitable for Tai Chi participants than a low-pose position.