Postural Responses to Sudden Horizontal Perturbations in Tai Chi Practitioners

Author: Jernej Sever1, Jan Babič2, Žiga Kozinc3,4, Nejc Šarabon3,5,6
1 Center Premik, Ltd., Center for Psychophysical Development, 1000 Ljubljana, Slovenia.
2 Laboratory for Neuromechanics and Biorobotics, Jožef Stefan Institute, 1000 Ljubljana, Slovenia.
3 Andrej Marusic Institute, Department of Health Study, University of Primorska, 6000 Koper, Slovenia.
4 Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenia.
5 Human Health Department, InnoRenew CoE, 6310 Izola, Slovenia.
6 Laboratory for Motor Control and Motor Behavior, S2P, Science to Practice, Ltd., 1000 Ljubljana, Slovenia.
Conference/Journal: Int J Environ Res Public Health
Date published: 2021 Mar 7
Other: Volume ID: 18 , Issue ID: 5 , Pages: 2692 , Special Notes: doi: 10.3390/ijerph18052692. , Word Count: 280

Tai Chi has been shown to elicit numerous positive effects on health and well-being. In this study, we examined reactive postural control after sudden unloading horizontal perturbations, which resembled situations encountered during Tai Chi. The study involved 20 participants, 10 in the Tai Chi group (age: 37.4 ± 7.8 years), who had been regularly training the push-hand technique for at least 7 years, and 10 in the control group, consisting of healthy adults (age: 28.8 ± 5.0). Perturbations were applied at three different positions (hips, shoulders, and arms) via the load-release paradigm. Twenty measurements were carried out for each perturbation position. We measured peak vertical and horizontal forces on the ground (expressed percentage of body mass (%BM)), peak center of pressure displacement and peak horizontal and vertical velocities at the knee, hip and shoulder joints. The Tai Chi group exhibited smaller increases in vertical ground reaction forces when perturbations were applied at the hips (11.5 ± 2.1 vs. 19.6 ± 5.5 %BW; p = 0.002) and the arms (14.1 ± 4.2 vs. 23.2 ± 8.4 %BW; p = 0.005). They also responded with higher horizontal force increase after hip perturbation (16.2 ± 3.2 vs. 13.1 ± 2.5 %BW; p < 0.001). Similar findings were found when observing various outcomes related to velocities of vertical movement. The Tai Chi group also showed lower speeds of backward movement of the knee (p = 0.005-0.009) after hip (0.49 ± 0.13 vs. 0.85 ± 0.14 m/s; p = 0.005) and arm perturbations (0.97 ± 0.18 vs. 1.71 ± 0.29 m/s; p = 0.005). Center of pressure displacements were similar between groups. Our study demonstrated that engaging in Tai Chi could be beneficial to reactive postural responses after sudden perturbations in a horizontal direction; however, future interventional studies are needed to directly confirm this. Moreover, because of the age difference between the groups, some confounding effects of age cannot be ruled out.

Keywords: balance; martial arts; postural control; posture; reaction.

PMID: 33800052 DOI: 10.3390/ijerph18052692