By Janice T. Radak
Tai chi, a traditional Chinese mind-body exercise, consists of body rotations, semi-squat positions, and slow, controlled movements. As one moves through the various stances, balance shifts between single- and double-leg support, thereby incorporating gait, balance, and lower-limb strength training all at once. As such, it is well suited to individuals of all ages and is considered an evidence-based exercise prescription option for many health conditions. Indeed, many major healthcare organizations, such as the National Council on Aging and the Centers for Disease Control and Prevention, recommend tai chi programs for falls prevention in older adults.
Although the number of people participating in the practice of tai chi in the United States has grown only nominally since 2008 (from 3.42 million to 3.79 million), evidence continues to mount about its benefit for falls prevention.20
Studies of tai chi and falls risk reduction
2017 meta-analysis shows efficacy. Lomas-Vega and colleagues,21 in a 2017 meta-analysis, examined 10 studies comprising 2,600 participants (age range, 56 to 98 years) who had taken part in hour-long tai chi classes 1 to 3 times a week for 12 to 26 weeks. The researchers found high-quality evidence that participants were able to significantly reduce their risk of falling by 43% over the short term (<12 months) and by 13% over the long term (≥12 months) although not significantly. In looking at injurious falls, Lomas-Vega found low-quality evidence that participants were able to reduce their risk of sustaining an injury by 50% over the short term, although that reduction dropped to 28% over the long term. The findings suggest that tai chi, as an intervention, is a better falls preventive intervention than other approaches, such as physical therapy, balance training, resistance exercises, stretching, and yoga.
Physiotherapy Evidence Database (PEDro)
PEDro trial reports are rated with a checklist called the PEDro scale,24 which was created to help PEDro users rapidly identify trials that are likely to be internally valid and have sufficient statistical information to guide clinical decision-making. Each trial report is given a total PEDro score that ranges from 0 to 10; the average total PEDro score is 5.1, with a standard deviation of 1.6. Thirty-six percent of all trial reports show moderate-to-high quality—i.e., ≥ 6/10 on the PEDro scale, thus making the trials in the Zou study above average.
—Janice T. Radak
2018 study: Lower-limb proprioception is improved. Zou and co-workers22 earlier this year published the results of a systematic review and meta-analysis that looked specifically at the effects of tai chi on lower-limb proprioception in adults 55 years and older. Proprioception declines with age, impairing balance, so identifying strategies to mitigate that decline is critical to reducing the health burden of falls in this population.
The investigators examined 11 studies and calculated pooled effect size (standardized mean difference [SMD]). PEDro scores for the tai chi studies rvanged from 5 to 8 points (mean = 6.7) (see “Physiotherapy Evidence Database [PEDro],” page 28). Based on their calculations, Zou found that tai chi had significantly positive effects on lower-limb joint proprioception, with moderate-to-large effect sizes, including on:
- ankle plantar flexion: SMD = -0.55 (95% confidence interval [CI], -0.9 to -0.2); P = .002;, I = 0%, N = 162
- dorsiflexion: SMD = -0.75 (95% CI, -1.11 to -0.39); P<0.001; I = 0%; N = 162
- nondominant/left-knee flexion: SMD = -0.71 (95% CI, -1.10 to -0.41); P < .001; I = 25.1%; N = 266
- dominant/right-knee flexion: SMD = -0.82 (95% CI, -1.06 to -0.58); P < .001, I = 33.8%, N = 464.
Specific to knees, the researchers identified control of knee movement as fundamental for older adults for maintaining center of gravity, particularly during activities of daily living. Tai chi “involves symmetrical and dynamic weight shifting and single-double stance in multiple directions, through precise control of both knees flexion and extension,” the authors wrote, such that “significant improvement in bilateral knee proprioception may be achieved through a ‘common motor program’ shared between two brain hemispheres. Our [previous] bilateral proprioceptive study23 showed that significant correlation exists between left and right knees, suggesting that proprioceptive improvement in one knee through tai chi exercise may also have a positive effect on the contralateral knee.”
Zou concluded that the results of this analysis substantiate moderate-to-strong evidence that tai chi is safe and effective for maintaining and improving lower-limb proprioception in adults older than 55 years.