Tai Chi

Knee Biomechanics of Selected Knee Unfriendly Movement Elements in 42-Form Tai Ji

Tai Ji is one of the recommended non-pharmacologic treatments for knee osteoarthritis (OA), but it is not clear if all Tai Ji movements would be suitable and beneficial for knee OA patients. PURPOSE: To examine knee biomechanical characteristics of the selected knee unfriendly Tai Ji movement elements performed in high-pose position compared to slow walking. METHODS: Seventeen healthy participants (age: 23.9 ± 2.7 years, height: 1.73 ± 0.08 m, body mass: 69.0 ± 13.0 kg) performed three trials in each of the following five test conditions: level walking at 0.8 m/s and four identified knee unfriendly Tai Ji movement elements: lunge, pushdown and kick performed in high-pose position (35 ± 5°) and pseudo-step. Simultaneous collection of 3D kinematics (120 Hz) and ground reaction forces (1200 Hz) was conducted. A one-way ANOVA was performed with post hoc paired samples t-tests to determine differences of the high-pose lunge, pushdown, and kick, and pseudo-step and walking. RESULTS: Knee flexion range of motion for high-pose lunge (29.5°), pushdown (24.3°) and kick (11.1°) was lower than pseudo-step (45.0°, p<0.001 for all comparisons) and walking (47.8°, p<0.001 for all comparisons). Peak knee extensor moment was lower in high-pose lunge (1.04 Nm/kg), pushdown (1.01 Nm/kg) and kick (0.48 Nm/kg) than pseudo-step (1.46 Nm/kg, p<0.001 for all comparisons), but higher than walking (0.38 Nm/kg, p<0.001 for all comparisons) except for kick. Peak knee abduction moment was higher in pseudo-step (-0.61 Nm/kg) than high-pose pushdown (-0.43 Nm/kg), kick (-0.44 Nm/kg), and walking (-0.45 Nm/kg, for all comparisons p<0.001). CONCLUSION: These findings demonstrate higher peak knee extensor moment in most of the Tai Ji knee unfriendly movement elements compared to slow walking. It is recommended that Tai Ji participants with knee OA and other knee pathological conditions modify knee unfriendly movement elements (e.g. lunge) and reduce the size of their movements to minimize knee joint loading. The Tai Ji movement elements including pushdown and pseudo-step should be avoided in the Tai Ji exercises designed for knee OA patients.

Listed In: Biomechanics