Introduction

Stroke has high morbidity, mortality, and disability rates, and approximately two million people each year suffer from stroke. Consequently, 70%–80% of stroke patients cannot live independently because of disability [1]. In 2010, stroke remained the first leading cause of death and became the second leading cause of life years lost in China. Although a combination of mass and high-risk approaches for stroke prevention showed encouraging effects among the Chinese population, the stroke burden in China continues to increase over the last two decades [2, 3].

Past studies have indicated that balance and gait dysfunction is the common problems in stroke patients. This disability influences patient walking ability and quality of life. Proprioception often decreases in stroke patients, which causes patients to depend excessively on visual sense, and maybe they would wrongly rely on visual sense, which causes sensory integration disorder and abnormal compensatory strategies, leading to inappropriate body response to interference, inability to maintain stability, and decline in motor control skills. Finally, caused Falling [4, 5]. Falling is one of the most common complications suffered by stroke patients during their rehabilitation period [6]. A survey conducted by the emergency department from 1992 to 1995 in the United States found that falls are a major cause of damage. Children under the age of five fall from external causes. Accordingly, falling is more common in elderly patients over 65 years old [7], and the fifth factor which caused of death in the elderly. About two-thirds of accidental deaths, which reached 70% in elderly patients aged 75 years old and above, are caused by falls [8]. According to the survey, at least 20 million of the elderly fall 20 million times a year in China, and more than CNY 5 billion and CNY 80 to 160 billion are spent in direct medical and social costs, respectively [9, 10]. In addition, according to the national economic and social development statistical bulletin of the 2009 and 2008 statistics yearbooks, the average hospitalization cost for every cerebrovascular disease is approximately CNY 7,267.6. This value is half the annual income of urban residents and 1.5 times that of farmers[11–13]. So patients with stroke, their families, and society would shoulder heavy economic burdens because of these factors. This trend has profound financial and social consequences[14].

Hence, effectively treating stroke is important. Many studies have shown that engaging in sports is a very effective method of improving neuromuscular function. However, many movement techniques are monotonous, or certain strength exercises are beyond the patients' ability [15]. Exercise therapy, as a form of non-drug therapy, provides patients with greater benefits on physical function [16, 17]. Because brain plasticity is the basis of training exercises for patients with stroke, who are under limb function recovery. Exercise training promotes spontaneous neural functional recovery and restores brain function in patients with cerebrovascular disease to accelerate the process of functional recovery [18], which would help accelerate the rehabilitation process.domestic and foreign research has proven the benefits of exercise therapy in patients with cerebral apoplexy [16, 19]. Literature has also reported positive effects observed in patients with cerebral apoplexy after traditional Chinese exercise is used as a type of exercise therapy [8, 20–22].

Traditional Chinese exercise is a self methodology and theory of mental and physical exercise which was created by ancient Chinese people in their long life and labor. Including Taiji, Baduanjin, Yijinjing, Liuzijue and so on. As a low cost, easy to learn, highly safe, and appropriate aerobic exercise, traditional Chinese exercise is suitable for old people. In addition to these advantages, traditional Chinese exercise also offers additional benefits to the traditional method of stroke rehabilitation training by combining physical movements with mental focus and relaxation [23, 24]. Certain studies have shown that traditional Chinese exercise is a safe choice for patients with chronic illness or disabilities [25]. Tai chi as a type of representative traditional Chinese exercise, is a popular exercise method among the elderly, especially in Asia. Tai chi is divided into many genres according to different origins. These styles include the Yang, Wu, and Chen styles. Though there are differences of posture and the position of the center of gravity, all styles incorporate slowness, rhythmic movements, relaxation, mental concentration, movement coordination, and flow into the next one with elements of meditation, body awareness, and imagery while breathing deeply [26–28]. Some studies have found that practicing traditional Chinese exercise improves the ability of gait and balance and increases muscle strength for motor system function, which was useful for patients with stroke, and even for healthy adults [20–22].

Different opinions always exist. Whether traditional Chinese exercise is more beneficial in improving physical function in patients with stroke than other exercise therapy or without intervention is presently vague. A systematic review of adverse event reports in randomized trials [29] has reported certain adverse effects. These effects include muscle problems [30–32] and dizziness or hypotension [33]. Other patients feel pain in certain body parts (e.g., back, foot, and knee) or ankle sprains [23, 30, 31, 33–36]. Considering the preceding observations, traditional Chinese exercise maybe make things worse.

However, no systematic review on the efficacy of traditional Chinese exercise on the physical function of stroke patients has been found from electronic databases. Hence, this review evaluates the efficacy of traditional Chinese exercise in the physical function of stroke patients. This systematic review provides information that could help clinicians make evidence-based decisions on the use of traditional Chinese training for stroke patients.

Methods

Results

Search results

A total of 1833 articles were searched from PubMed, Embase, Cochrane Library, EBSCO, Web of Science, and CNKI. Accordingly, 59 potentially eligible studies were identified based on their titles and abstracts. Only 9 articles [38–46] met the inclusion criteria after the entirety of the 59 articles was reviewed. In addition, 50 articles were excluded because they either included participants without stroke or did not use traditional Chinese exercise for stroke treatment. Other studies were also excluded because the original data were no longer available from either the article or the author. Others had been excluded because they were non-randomized controlled studies or their outcome was irrelevant for the present review. Fig 1 outlines the process of identifying the qualified articles.

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Fig 1. Flow chart of the study selection procedure.

For details of study identification.

https://doi.org/10.1371/journal.pone.0135932.g001

Study characteristics

9 articles were included, All included articles aimed to examine the efficacy of traditional Chinese exercise on the physical function of patients with stroke. all trials were published between 2004 and 2013. And the detailed description we can see from the Table 1. All of the study were the single-center trials. Three types of interventions were used; six studies used Tai chi [38–43], two studies used Baduanjin [44, 45], and one used Yijinjing[46]. All studies were from three countries, China [38, 41–46], America [40] and Israel [39]. Data from 820 participants were extracted.

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Table 1. Characteristics of Included Studies.

https://doi.org/10.1371/journal.pone.0135932.t001

Quality of the evidence

The Cochrane Collaboration recommendation indicated that every article indicated a high bias risk. A high holistic risk of bias was related to the evidence for this systematic review. Randomization was used in each article, and only two articles (22.2%) adopted the method of allocation concealment. The method of blinding the participants to the allocated treatment was used in three (22.2%) of the included articles, and six articles (66.6%) were unclear whether adopted the method of blinding of outcome assessments. All study describe the patients who withdrew from the study. The incomplete outcome in all the included articles resulted in a low bias risk. In all, all included studies were considered high risk of bias (S1 Fig). The detail of risk of bias was illustrated in Table 2.

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Table 2. The risk of bias about included studies.

https://doi.org/10.1371/journal.pone.0135932.t002

And all studies included were randomized controlled trial, system GRADE recommended classification method was used to evaluate the BBS, Because of the inconsistency, imprecision and Publication Bias, the level of evidence was downgraded. And there was no reason to upgrade the strength of evidence because of the limitations in design in these included studies. Finally, the result showed that the quality of the evidence (GRADE) was very low.

Traditional Chinese exercise compared with other forms of exercise

Balance.

In total, nine articles (820 patients) evaluated the ability of balance with the following measures: the BBS, timed-up-and-go score, Fugl-Meyer (FM-B), limit of stability, sensory organization tests, the short physical performance battery for balance.

BBS: six trials[41–46] evaluated balance using the Berg balance scale(BBS), which was evaluated the balance by scale, and the higher score showed the better ability of balance, All of them (534 patients) were reported data at short-term follow-up period. We found significant improvements with traditional Chinese exercise for balance in the short term in a random-effects model [MD (95%CI) = 11.85 [5.41, 18.30], P < 0.00001], but the pooled estimate of effect for the BBS is extremely heterogeneous (I-squared 99%) (Fig 2). A sensitivity analysis was performed and there was no substantial modification of our estimates after exclusion of individual study one by one.

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Fig 2. Forest plot for traditional Chinese exercise on balance in short term.

Short term: not longer than 3 months; BBS = Berg balance score; SD = standard deviation; 95% CI = 95% confidence intervals; IV = inverse variance.

https://doi.org/10.1371/journal.pone.0135932.g002

Other outcomes: In addition to BBS, we found that one article (34 patients) used the the FM-B (which was similar with BBS) to demonstrate that Yijinjing improved the ability of balance for stroke patients (P < 0.05) [46]. And the limit of stability, sensory organization tests and the timed-up-and-go score to evaluate the standing balance of stroke patients (136 patients), all data indicated that tai chi was more effective than general exercises (P < 0.05) [38]. Another article(145 patients) showed that the significantly improved between the effects of traditional Chinese and general exercises were observed using the the short physical performance battery (P < 0.05) [40].

However, there is a article showed that some other form (physiotherapy exercises focused on balance) significant improved balance ability for stroke patients compared with tai chi chuan practice (Berg test = 0.01, Romberg, and standing on one leg) [39].

Gait.

We used more than one measure of gait variables, and we preferentially included the following measures: the short physical performance battery for gait, gait speed, step length, length difference, Functional walking scale (FCA), 2-minute step test. And with the balance different, only individual gait variables was found, so we can't make the forest plot to quantification. We found that a article assessed the gait variables using the short physical performance battery and 2-minute step test (P < 0.05), significant differences were observed between groups at short-term (twelve weeks) [39]. In addition, another article showed that after 3 weeks and 6 weeks' treatment, the gait parameters(except the step length) and FCA were significantly improved and the difference had statistical significance (p<0.05) between the groups, and the Tai Chi group didn't have obvious improvement in step length within 3 weeks, only after 6 weeks did it show the obvious improvement. Significantly (P < 0.05) [41].

Discussion

Previous reviews have examined the results of traditional Chinese exercise versus some other forms of exercise or non-intervention on cardiorespiratory fitness or upper-extremity dysfunction with stroke patients or health adults [20, 23]. But none has focused on gait and balance for stroke patients. Gait and balance are important for stroke patients to prevent falls and worse consequences. Therefore, this review collated the evidence from a large number of trials, which evaluated the effect of traditional Chinese exercise on gait and balance for stroke. This meta-analysis includes 820 patients, who participated in 9 RCTs. And all of the included articles belong to short-term (≤ 3 months). Five even less than three months [41–45]. no adverse events are reported in the 9 RCTs included in the meta-analysis. And according to the system GREADE recommended, the quality of the evidence (GRADE) of BBS was very low, and the reason maybe extremely heterogeneous (I-squared 99%), imprecision or incomplete data, and publication bias according to the Funnel plot (Fig 3), because the dots represent the mean differences of individual trial estimates and the dotted line the point estimate of the mean effect indicating benefit from traditional Chinese exercise. The distribution of these dots to the right of the dotted line suggests that there may be the equivalent number of ‘negative’ trials that have not been included in this analysis [47].

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Fig 3. Funnel plot for traditional Chinese exercise on balance in short term.

Short term: not longer than 3 months.

https://doi.org/10.1371/journal.pone.0135932.g003

The results of this meta-analysis show that traditional Chinese exercise is better than other forms of exercise in improving the balance of patients with stroke significantly at short-term. Because of the disunity outcome indicators, we couldn’t finish the forest plot about gait. But, according to the result, Three trials [39, 40] showed a tendency to improve in gait [39–41]. So an increasing number of studies have shown that traditional Chinese exercise is effective for improving the ability of balance for patients with stroke, and maybe the gait. Some researchers suggest that traditional Chinese exercise improves joint stability, and the improved limits of stability are associated with improved functional performance [48]. In addition, no adverse events were reported between groups in this meta-analysis. But certain articles [29] assert that tai chi cannot cause terrible adverse events although it may be connected with minor musculoskeletal aches and pains. Attention should be paid to the appropriate method and strength to use when practicing this traditional Chinese exercise. However, poor and inconsistent reporting of adverse events greatly limits the conclusions determined as regards the safety of practicing tai chi.

The pooled estimate of effect for the BBS (Fig 2) is extremely heterogeneous (I-squared 99%). Maybe there are probably important clinical and methodological differences among studies that influence the difference between intervention and control(s).

1. Different in populations: In the six articles, some difference existed in inclusion criteria. Especially about the duration of stroke, the patients with convalescence (≤6 months) were included [41–45], and another three articles were the patients with period of stroke sequel [48]. Maybe the different baseline caused the extremely heterogeneous.
2. Different types: Traditional Chinese exercise does not only include tai chi but also other forms, such as baduanjin, qigong, wuqinxi. liuzijue, and so on. Even tai chi also has a lot of branches. In the six articles which was included, three articles’ intervention methods are Tai chi (one of them is Yang-style Tai chi, but another two were unclear), two articles are Baduanjin, and the rest is Yijinjing. Different forms of traditional Chinese exercise focus on different emphasis. This maybe a factor to cause the heterogeneity.
3. Different in experimental and control group: there are some difference in grouping for theses article. conventional medical treatment combined with traditional exercises exercise as a treatment for three articles [42, 44, 46], The remaining three articles [41, 43, 45], respectively traditional Chinese exercise combined with balancing function training, acupuncture and exercise therapy. Different treatments may lead to such the result.
4. Different in intensity and duration: Different intensity and duration may lead to different results. Accordingly, we find that different frequency of training was used for included articles. Bai Yan-jie and Zhang Ming [44, 45] took two times per day for six weeks, Zhou Zugang [41] took six times a week for six weeks, Xie Fei [43] choosed three times per day for two weeks, the remaining two are respectively six times a week for four weeks and five times a week for twelve weeks (Table 1).

Conclusions

Based on our results, we make the following recommendations. The positive findings of this study suggest traditional Chinese exercise has beneficial effects on the balance ability in short term, and maybe a tendency to improve gait. However, the conclusion was drawn according to the extreme heterogeneity, and evidence of better quality and from a larger sample size is required. In the future, uniform and accepted outcome of gait should be used in traditional Chinese exercise for patients with stroke. Systematic data collection at short, mid-, and long-term follow-up is essential.

Supporting Information

Acknowledgments

This work was supported by Innovation Program of Shanghai Municipal Education Commission (15ZZ084); Shanghai Committee of Science and Technology (14490503800); Shanghai Youth Science and Technology Sail Project (15YF1411400); Innovation Program of Shanghai University of Sport (yjscx2014008); Shanghai Key Lab of Human Performance (SUS), Ministry of Education. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.