The effects of tai chi chuan exercise training on countermovement jump performance in the elderly. Author: Ko BJ1, Hsu TY1, Huang CF2 Affiliation: <sup>1</sup>Department of Physical Education, National Taichung University of Education, Taichung, Taiwan. <sup>2</sup>Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan. Conference/Journal: Res Sports Med. Date published: 2020 Feb 13 Other: Volume ID: 1-9 , Special Notes: doi: 10.1080/15438627.2020.1727478. [Epub ahead of print] , Word Count: 198 This study sought to compare the biomechanical parameters of the lower extremities during a countermovement jump in elderly people who are engaged in frequent practice of tai chi chuan (TCG) and in the general population of healthy elderly people (HG). Each group included 12 participants. Ten Vicon Motion System infrared cameras and two Kistler force plates were employed for measurement. The jump height, duration, centre of mass (COM) displacement, joint ROM, and upward velocity were analysed in this study. Motion analysis and force platform data were combined to calculate joint moments and powers during the takeoff phase. The data were analysed using independent sample t-tests. The results showed that the tai chi chuan practitioner group (0.13 m) achieved 44% higher jump heights (p < 0.05). The COM displacement during squatting was lower in the TCG (0.25 m) than in the HG (0.19 m) (p < 0.05). The knee and ankle ROMs of the TCG were higher than those of the HG (p < 0.05). Peak knee moment 23% and peak knee power 32% higher in TCG compared to the HG (p < 0.05), suggesting that frequent practice of tai chi chuan may slow the rate of knee degeneration. KEYWORDS: Jump height; fall risk; knee moment; knee power PMID: 32050791 DOI: 10.1080/15438627.2020.1727478