Knee Biomechanical Characteristics of Knee Unfriendly Movements in 42-form Tai Ji

Tai Ji was one of recommended non-pharmacologic treatments for knee OA, but it is not clear that if all of the Tai Ji movements would be suitable and beneficial for knee OA patients. The purpose of this study was to examine 1) GRF and knee kinematic and kinetic characteristics of the identified knee unfriendly Tai Ji movements including lunges, pushdown, kick and pseudo-step 2) effects of high- and low-pose of these movements on those characteristics, and 3) compare biomechanical variables between the Tai Ji movements and slow waking. Seventeen volunteers performed three trials in each of eight movement conditions: high and low lunges, high and low pushdown, high and low kick and toe-touched pseudo-step and slow walking. The peak knee extensor moment was 67.3%, 94.0% and 97.9% greater in the low-pose lunge, pushdown and kick than those of high-pose movements (p<0.001 for all comparisons). The high-pose also caused a reduced peak knee abduction moment (p=0.004) and knee adduction ROM (p<0.001) in lunge. Greater peak knee extensor moments were found in all Tai Ji movements of both poses, except for high pose kick, compared to slow walking (p<0.001). Based on the results, the high-pose position would be more suitable for Tai Ji participants with knee OA than low-pose. Further study may be needed to demonstrate effects of high-pose Tai Ji training in managing pain and physical functions of knee OA patients.