Abstract
Hypertension is a serious health risk world-wide. Isometric exercise has shown to reduce resting blood pressure (RBP) in hypotensive and normotensive individuals. Since they are isometric in nature, Tai Chi stances may also show RBP improvements in similar exercise protocols. The purpose of this study was to evaluate acute blood pressure responses in two isometric stances commonly practiced in Tai Chi. 20 normotensive subjects (13 females and 7 males, Age: 25.4 ± 4.5 years, Height: 171.1 ± 10.1 CM, Weight: 70.1 ± KG) performed two different stances, separated by at least 24 hours, for two 2-minute bouts with a 1-minute break in between. Systolic and diastolic blood pressure (SBP, DBP) were taken at rest 10 minutes before exercise, during the break, immediately post, 5 minutes post, and 10 minutes post exercise. Muscle activity of the vastus lateralis (VL) and biceps femoris (BF) was measured via EMG and reported as %MVC. Ten minutes after performing the empty stance (ES) average resting BP decreased significantly by -4 ± 5.0 mmHg and -3 ± 6.7 mmHg (SBP, DBP). The front stance (FS) average SBP decreased -2 ± 5.5 mmHg and DBP changed 0 ± 6.7 mmHg but did not reach levels of significance. No significant correlations with BP changes and muscle activity were found in either stance. While the mechanisms remain unclear, the changes in RBP are significant considering that only four minutes of exercise was performed in total and that these were normotensive individuals. As these reductions were similar to those noticed after several weeks of other forms of isometric exercise, longer term training studies are warranted to determine the full benefits of Tai Chi stance training.