Effect and Mechanism of Traditional Chinese Medicine Exercise Therapy on Stroke Recovery

Stroke is currently the second largest contributor to disability-adjusted life years (DALYs) in developing countries, and it is the third largest contributor to DALYs in developed countries. It requires a large number of resources from the health care system every year, which places a great burden on society, families, and individuals. The treatment of traditional Chinese medicine exercise therapy (TCMET) during stroke recovery has become a hot topic of current research due to its few adverse events and high efficiency. This article sorts out the latest progress of TCMET on the recovery of stroke through the review method and explores its role and mechanism based on existing clinical and experimental studies. TCMET treatment of stroke recovery mainly includes Tai Chi, Baduanjin, Daoyin, Yi Jin Jing, five-fowl play, and six-character tips, which can effectively improve motor function, balance and coordination ability, cognitive dysfunction, nerve function, depression or emotional state, daily living ability, and so on after stroke. The mechanisms of stroke treated by TCMET are discussed, and deficiencies in the literature are discussed and analyzed. It is hoped that some guiding suggestions will be provided for future clinical treatment and experimental studies.


Introduction
Stroke disease is also known as stroke. It is a type of disease that is mainly manifested by sudden coma, unconsciousness, half-body failure, tongue tilting, and unfavorable speech [1]. It is equivalent to the cerebrovascular accident (CVA) in modern medicine. According to the pathological results, stroke is divided into ischemic stroke, cerebral hemorrhage, subarachnoid hemorrhage, and mixed stroke. According to the 2020 Chinese Stroke Association Guidelines for Clinical Management of Cerebrovascular Diseases, stroke is clinically divided into three distinct stages: the acute stage, the recovery period, and the sequelae period. Te acute phase refers to the onset of illness within 1 month. Te recovery period is 1 month to half a year after the onset of the disease, and half a year later is the sequelae period [2].
Stroke is currently the second largest contributor to disability-adjusted life years (DALYs) in developing countries, and it is the third largest contributor to DALYs in developed countries [3]. Globally, 132.1 million DALYs have been lost [4]. Tis requires signifcant resources from the healthcare system [5]. Te incidence of stroke varies greatly according to the age structure of the population under study. With age, the incidence increases dramatically in both men and women. Te risk of disease in children under 15 years of age is 1 in 100,000, while the risk of disease in people aged 85 years and older is 1 in 33. Te incidence of stroke from the age of 55 to the age of 84 more than doubles every decade [6]. Stroke deaths in China in recent years have accounted for one-third of the total number of stroke deaths worldwide [7,8]. Tere are certainly regional diferences in the incidence of the disease, mostly in the northern and central regions. About 70% of stroke survivors have some degree of disability, including physical and mental disabilities, mobility restrictions, and participation restrictions [9]. Tis increases the burden of stroke-related disabilities in China and other countries around the world, putting enormous pressure on society, families, and individuals. With the advent of an aging population, these problems will become more pronounced in the future. How to solve the problem of disability caused by stroke will become the direction of continuous exploration in this research feld.
Traditional Chinese medicine exercise therapy (TCMET) is also known as Gong Fa. Under the guidance of holism in traditional Chinese medicine (TCM) and treatment based on syndrome diferentiation, there are certain exercise principles and operating methods, and through the coordination and unifcation of exercise, breathing, consciousness, and self-tuina, that is, the combination of "body adjustment, heart adjustment, and pranayama," a kind of exercise therapy is used to prevent and treat diseases and strengthen the body. During the exercise, it is required to relax the body and mind, pay attention to softness and rigidity, and static braking. In the state of relaxation and naturalness, body movement is used to practice shape, and breathing exercise is used to practice qi, while mind guidance is used to restore the normal operation of qi and blood around the body, so that the body can recover. TCMET is an important part of TCM and belongs to a kind of aerobic exercise of active exercise, mainly including Tai Chi, Baduanjin, Daoyin, Yi Jin Jing, fve-fowl play, six-character tips, Shaolin kung-fu, Relaxation exercise, and Standing pile exercise. For the study of stroke disease, the ancient Chinese physician Chao Yuanfang quoted many Daoyin methods in the "Health Care Formula Guide Method" in the "General Treatise on Causes and Manifestations of All Diseases" to treat stroke disease. Liu Wansu attaches great importance to the restoration of the motor function of stroke hemiplegia by TCM and early Daoyin tuina. TCMET is convenient, economical, and rarely causes adverse events; the safety, efcacy, and fall rates were also confrmed by literature studies [10][11][12]. Terefore, TCMET's treatment of stroke disease has attracted more and more attention.  Aug 29, 2022, through the keywords "Traditional Chinese Medicine Exercise Terapy," "Tai chi," "Baduanjin," "Daoyin," "Yi Jin Jing," "fve-fowl play," "six-character tips," "Shaolin kung-fu," "Health care exercises," "Relaxation exercises," "Standing pile exercises," and "Stroke" and adjusted according to diferent databases. Te search strategy of the PubMed database is shown in Table 1.

Literature Screening.
A total of 2571 articles were identifed in the search, and 228 articles were deemed potentially relevant through the exclusion of the title and abstract. Tere were 71 articles through reading the full text to exclude repeated publications, research proposals, abstracts, case studies, and conference papers. Te full text cannot be found and it is still in clinical trials. Te literature clearly did not belong to the stroke recovery period. Among them, there are 24 articles on Tai Chi, 18 articles on Baduanjin, 9 articles on Daoyin, 5 articles on Yi Jin Jing, 2 articles on fve-fowl play, 10 articles on six-character tips, and 3 articles on relaxation exercises (Figure 1).

Research Status
Judging from the published literature, the hot spots of research in the past decade have mainly focused on the treatment of the stroke recovery period with TCMET. By choosing this stage of treatment and the introduction of Western medical rehabilitation into China in the 1970s and 1980s and the gradual development of traditional Chinese medicine rehabilitation, the treatment of stroke has placed more and more emphasis on the grasp of the time window. Trough clinical studies, the earlier the intervention in traditional Chinese and Western medicine rehabilitation, commonly known as early introduction, the more benefcial it is to the patient's later recovery. Multidisciplinary crossfusion treatment has become a trend in stroke treatment. TCMET plays a role in the recovery period of stroke with its unique advantages. At present, more research studies are being conducted on Tai Chi, Baduanjin, Daoyin, Yi Jin Jing, fve-fowl play, six-character tips, and Relaxation exercises. Te summarized current status of TCMET in the recovery period of stroke is shown in Tables 2-7. From Table 3, Tai Chi uses the simplifed 24 forms issued by the General Administration of Sports of China in 2003 and improves on this basis, choosing a single type of exercise such as Tai Chi Yunshou or choosing the 8 postures that are most commonly used for stroke patients. Te 8 postures are commencing, step back and whirl arms, knee hugging and twist step, wild horse mane, yunshou, hand waving pipa, picking the tail, ending posture, etc., which include moving forward, backward, left, and right from the fxed step. It also emphasizes the "waist as the axis" to drive the movement training of upper limbs, hips, knees, and ankles. During the practice, the waist and hips are required to be loose and heavy, with breathing exercises..
In the specifc practice, attention is paid step by step to specifc exercises, from easy to difcult, practiced in stages, and certain protective measures are taken. Te intervention time was 20-60 minutes each time, 1-2 times a day and 2-5 times a week. Some literature studies used a combination of group exercises and individual exercises, and the total intervention time was half a month to 6 months. In terms of clinical efcacy, it mainly improved motor function, balance ability, cognitive impairment, neurological function, daily living ability, emotion regulation, cardiopulmonary function, safety, and fall prevention in stroke patients, and it was reported that with the extension of intervention time, the efect was more signifcant. From the perspective of literature quality, except for one piece of the literature that is unclear whether to use randomized control, the rest of the literature used randomized controlled trials, compared the baseline data of the literature, and recorded the shedding cases, so the results of the included literature studies were recommended.
From Table 4, Baduanjin refers to the "Fitness Qigong Baduanjin" standard issued by the General Administration of Sports of China in 2003 [83], and the Eighteen section brocade is a training method that combines Tai Chi, Baduanjin, and modern ftness exercises. Te included literature mainly used Baduanjin or eighteen sections brocade 2 Evidence-Based Complementary and Alternative Medicine combined with other methods for the treatment of stroke, and the efcacy was signifcantly better than that of Baduanjin alone or eighteen section brocade. Te improvement after stroke is mainly in motor function, balance function, cognitive function, depression after stroke, and daily living ability. From the perspective of intervention time, compared with Tai Chi, the intervention time of Baduanjin is shorter, generally 20-30 minutes each time, generally once a day in the morning and evening, 40-50 minutes 3 times a week, and the intensity of exercise is in line with the aerobic activity intensity recommended by the American College of Sports Medicine and the American Heart Association for the health of the elderly in 2007 [84]. In terms of the evaluation of literature quality, the included literature all adopted the randomized control method, but there were certain confounding factors due to the combination of multiple methods. Te insufcient sample size and a wide range of centers afected the results.
It can be seen from Table 5 that the choice of Daoyin is mainly caused by causes and manifestations of all diseases, which refect the combination of breath, heart, and body adjustment. Sitting, standing, and horizontal training for diferent parts can be adopted. Te curative efect of Daoyin combined with basic rehabilitation is better than simple basic rehabilitation. Te curative efect of stroke is mainly on motor function, balance and coordination ability, daily living ability, and so on. Te safety and fall prevention of stroke have not been found in the relevant literature. Te total intervention time is relatively short, and the relationship between extended practice time and efcacy remains to be verifed.

Refs
Tai Chi (n � 1716) Based on ancient Chinese philosophical ideas such as the theory of yin and yang and the principle of Tai Chi, it is a traditional boxing technique that integrates functions such as temperament, physical ftness, and technical confrontation Treating the symptoms and signs during the recovery of stroke [11, Baduanjin (n �

718)
Daoyin is the earliest and most distinctive exercise method in many therapies of TCM, which is a way of organically combining breathing, body movement, idea guidance, and self-tuina, which plays a unique role in health care, disease treatment, and rehabilitation Treating the symptoms and signs during the recovery of stroke [54][55][56][57][58][59][60][61][62] Six-character tips (n � 828) six-character tips is a set of tuna health care methods handed down in ancient China, focusing on breathing and exhaling using "Xu, He, Hu, Xi, Chui, Xi," the specifc pronunciation of the six characters, mouth training to afect the operation of diferent organ meridian qi and blood, supplemented by corresponding body movements and ideas, and then achieving the purpose of strengthening the body and maintaining health and rehabilitation Treating the symptoms and signs during the recovery of stroke [63][64][65][66][67][68][69][70][71][72] Yi Jin Jing (n �

601)
Yi Jin Jing originated from the ancient Chinese health care guidance technique, through the use of subjective energy, a comprehensive exercise of self-body and mind, changing the bones and muscles, making them a strong set of traditional exercises. It uses a certain posture to induce breathing and gradually strengthens the function of the tendons and internal organs Treating the symptoms and signs during the recovery of stroke [73][74][75][76][77] Five-fowl play (n � 120) Five-fowl play is an ancient traditional exercise that imitates the movements of fve animals, namely tigers, deer, bears, apes, and birds (cranes), and is a guiding method for health care and strengthening the body Five-fowl play can signifcantly improve the motor function, balance function, and ability of daily living in patients with stroke hemiplegia [78,79] Relaxation exercises (n �

209)
Relaxation exercises are a kind of meditation exercise, which organically combines the three practice methods of mind, breathing, and posture and adopts postures such as "standing, sitting, and lying down" to relax various parts of the body from the head to the toe, from the top to the bottom, to adjust the whole body to a comfortable, relaxed, and natural state Treating the symptoms and signs during the recovery of stroke [80][81][82] 4 Evidence-Based Complementary and Alternative Medicine Note. Te column of course of disease is based on month, and those less than 1 month are converted proportionally; in the column of intervention time, the time of each intervention is calculated as minutes, and the total time of intervention is calculated as months. Each exercise therapy status analysis in TCMET was expressed in such a discounted way in terms of the course of disease and intervention time. Note. * indicates that the course of the disease was found in baseline data and expressed as a mean, not clearly defned in the inclusion criteria. 6 Evidence-Based Complementary and Alternative Medicine   Administration of Sports of China [85], and some literature combines Daoyin on this basis [86], which can be exercised step by step in supine, sitting, and standing positions. Te treatment of stroke is mainly to improve the patient's lung and respiratory function, speech disorders, and so on, and the efcacy of the combination of other methods is signifcantly better than that of other methods alone. One piece of literature on the source of the case involved a multicentre study [64], but there were limitations and the overall intervention time was short. From Table 7, it can be concluded that Yi Jin Jing, fvefowl play, and Relaxation exercises are the three TCMETs with the least amount of literature research and the total intervention time is short, which mainly improves motor function and daily living ability of stroke patients. Te effcacy of combination with other methods is better than that of other methods alone.

Evidence-Based Complementary and Alternative Medicine
Subgroup analysis of each TCMET therapy is conducted in Tables 3-7. Diferent TCMETs have common efects on stroke recovery, which also have diferent characteristics. Te summarized efcacy and frequency of TCMET on stroke recovery are shown in Figure 2.
It can be seen from Figure 2 that Taichi and Baduanjin have conducted extensive studies, and TCMET has improved motor function after stroke. Daoyin is mainly used to improve balance and coordination ability and daily living ability in addition to motor function. Besides, Baduanjin has conducted more studies on cognitive function, depression, and emotional state after stroke. Studies on six-character tips are mainly used in lung function and speech disorders. Tere is relatively little literature on Yi Jin Jing, fve-fowl play, and relaxation exercises. Only Taichi and Baduanjin are involved in safety evaluation. However, only Taichi has a special literature study on fall prevention in TCMET.
From the above research and analysis of TCMET on the recovery period of stroke, its efcacy in combination with other therapies is worthy of recognition, which is a useful supplement of modern Western medicine rehabilitation in the recovery period of stroke and is worthy of promotion and application. Subsequent studies were provided in terms of the use, sample size, intervention time, and tendency of each therapy to facilitate function recovery during stroke recovery.

To Explore the Mechanism of TCMETfrom Brain Function Remodeling
4.1.1. From the Functional Structure of the Brain. From the cortex research, Chen Yiyun and Liu believe that stroke patients with hemiplegia actively and consciously practice such as Baduanjin can enhance the activity of the motor center of the human brain cortex and increase the excitability of nerve cells [87]. Liu and Li found that the cerebral cortex was in a special state during the Daoyin exercise, which may be one of the mechanisms of its infuence on brain function. In addition, it was also found that skin temperature changes signifcantly in the process of Daoyin exercise, suggesting that Daoyin exercise can afect autonomic nervous function [88]. Zhu found that specifc Daoyin techniques can activate specifc areas of the cerebral cortex and promote plastic changes in the central nervous system, and it is believed that the active use of limbs can cause plasticity changes in the function of the brain's motor cortex [89]. From the study of brain gray matter, Ye is based on voxel morphological analysis, and by comparing MRI before and after treatment, it is believed that Baduanjin's efect on gray matter volume in patients with mild cognitive impairment (MCI) is signifcantly related to the changes in the gray matter structure in the right middle temporal gyrus, the right middle occipital lobe, and the right posterior cerebellar lobe [90]. Based on multimodal magnetic resonance imaging, Lu explored the efect of Tai Chi exercise on cognitive function and believed that Tai Chi tends to adjust the functional connectivity of the brain's default mode network and change the structure of white matter fbers [91]. In a study published in 2012 by Xue et al. in Professor Chen Lidian's team, participants were scanned by resting-state fMRI before and after the 12-week Tai Chi and Baduanjin practice interventions, and the memory function of the subjects was evaluated, aiming to explore whether they could improve memory function and regulate the resting function connection of the hippocampus. Te results showed that both Tai Chi and Baduanjin could signifcantly enhance the memory function of the participants, and the strength of the functional connection between the bilateral hippocampus and the medial prefrontal cortex in the Tai Chi group increased signifcantly. Tis change in functional connectivity has a signifcant correlation with the improvement of memory function in participants, and the intrinsic efect mechanism of Tai Chi in improving memory function is partially illustrated at the level of the central nervous system [92].

Study the Efects of Brain Waves.
Chen Chi's research on the efect of ftness qigong six-character tips on brain waves in patients with mild cognitive dysfunction, from the analysis of brain waves (EEG) before and after practice, shows that the approximate entropy is signifcantly reduced at the beginning of 1 month of practice, the EEG tends to be orderly, and the approximate entropy is still slightly reduced after 3 months of practice, indicating that insisting on practicing ftness qigong sixcharacter tips can keep brain waves more orderly, manifested as memory loss and improvement, improved ability to respond to things, and a calm mood [93]. during the rehabilitation process, thereby promoting the rehabilitation of specifed movements to a certain extent [94].

Blood Flow
Studies from the Brain. Li et al. observed the circulatory state of brain blood circulation in patients after Daoyin therapy, and the cerebral blood fow chart of patients after Daoyin therapy showed that the blood infow time was shortened and the tension of blood ducts decreased signifcantly, indicating that Daoyin therapy can improve the brain blood fow chart, improve blood duct elasticity, and increase cerebral blood volume, particularly vertebrobasilar volume [95].

Study on Changes in Cerebral Blood Oxygen.
Qiang et al. measured the brain oxygen metabolism state of a senior Shaolin kung-fu exerciser during exercise by nearinfrared spectrophotometry, and the amount of oxygenated hemoglobin was slightly reduced compared with that of the quiet sitting position during the Shaolin kung-fu exercise, and the total hemoglobin amount was almost unchanged. Te ratio of oxygenated hemoglobin to oxyhemoglobin in the total hemoglobin volume during the Shaolin kung-fu exercise decreased slightly, and the amount of oxyhemoglobin increased slightly. In terms of oxygen saturation, compared with the quiet sitting position before the Shaolin kung-fu exercise, the Shaolin kung-fu exercise is only reduced by about 1-2%, which cannot be said to have changed signifcantly. In experiments with senior Shaolin kung-fu exercisers, despite the intensity of isotonic muscle contractions, the total amount of hemoglobin and oxygen saturation in the brain have been maintained within the physiological range. Tis suggests that the "Natural respiration" method practiced through long-term exercise can promote the very economical oxygen consumption of brain tissue, efectively inhibiting the increase in the amount of deoxyhemoglobin in the blood. Correct, moderate Shaolin kung-fu exercises do not afect the homeostasis of the human environment but can improve the oxygenation capacity of brain tissue [96].

To Explore the Mechanism of TCMET at the Molecular
Level. Wang Qian et al. discussed the mechanism of eighteen-section brocade combined acupuncture treatment to improve exercise quality and motor function of patients from the levels of serum matrix metalloproteinases-9 (MMP-9), erythropoietin (EPO), and homocysteine (Hcy). In normal brain tissue, EPO is hardly expressed, but its content is signifcantly increased in stroke and can be used as a marker of brain damage [97]. HCY is a risk factor for ischemic stroke and atherosclerosis. Te study found that MMP-9 is closely related to the structure of the blood vessel wall and the permeability of the blood-brain barrier, which can refect the edema area and the degree of cerebral infarction in stroke patients. Te serum MMP-9, EPO, and Hcy levels in the observation group were signifcantly lower than those in the control group, indicating that acupuncture combined with eighteen-section brocade could reduce brain injury by reducing serum MMP-9, EPO, and Hcy levels [49]. In addition, some researchers have signifcantly reduced the urine uric acid content before and after practicing standing pile exercises, which shows that the synthesis of nucleic acids is greater than the decomposition during the exercise, and then the synthesis of nuclear proteins can be introduced to be greater than the decomposition. Whether the resynthesis rate of nuclear protein is accelerated or the decomposition rate of nuclear protein is slowed down during practice, the Evidence-Based Complementary and Alternative Medicine body will enter a state of energy storage. In turn, it will have a good impact on the function of various organs in the human body. It is believed that the clear-eyed, energetic selfproprioception that occurs after practicing is related to this good efect of infuence [98].

To Explore the Mechanism of TCMETfrom the Changes in
Lung Ventilation. Ding et al. explored the mechanism of sixcharacter tips in the treatment of respiratory control ability in patients with motor speech disorder after stroke by comparing six-character tips with traditional breathing training. Its mechanism may be the same as the "six-character tips" which emphasizes the simultaneous training of breathing and pronunciation. Breathing pronunciation is gentle, slow, and uniform, in fact, a low-load, slow-rate breathing training. It is easier to activate the main respiratory muscle group composed of slow muscle fbers than simple respiratory muscle reinforcement training, and it is not easy to cause fatigue and does not cause excessive tension in the vocal cords [64]. In addition, the vocalization method of the "six-character tips" is conducive to the stabilization of subglottic pressure, providing sufcient airfow for vocal cord vibration, ensuring the duration and tone of laryngeal pronunciation, and gradually adjusting the patient's breathing mode to abdominal breathing during training, which helps to enhance the patient's respiratory function and provide continuous and stable respiratory airfow support for pronunciation [99]. Moreover, the "six-character tips" guided action can fully mobilize the respiratory muscles and increase the amplitude of abdominal movement before and after and the range of movement of the diaphragm up and down, which is conducive to increasing the volume of the chest cavity and lung capacity [99,100]. Some studies have further shown that when training the "Xu" word in the six-character tips of breathing, the air tract and extrathoracic resistance of the body can be increased when exhaling, and the squeeze of the airway by the pressure in the chest can be reduced through this way. Te collapse of the small airway and the premature closure of the bronchi are avoided, and the residual air volume in the lungs is reduced, so that the phenomenon of airfow obstruction is reduced, and the role of improving the lung function of the body can be achieved [72]. Some researchers have used Tai Chi to regulate post-stroke cardiopulmonary function by means that the heart rate variability (HRV) of long-term Tai Chi practitioners will be greatly improved. Secondly, the abdominal breathing of Qi Shen Dantian during the long-term practice of Tai Chi not only exercises the respiratory muscles, but also strengthens the depth of breathing, expands the lung capacity, improves the microcirculation system, improves the gas exchange capacity, and has a more obvious efect of increasing the velocity max [22]. In summary, the above studies explore the mechanism of TCMET in stroke treatment from the aspects of brain function remodeling, molecular mechanism, and lung ventilation change mechanism, and prove how TCMET plays a role in stroke treatment. However, the research on the mechanism of action is still relatively weak, and the research on the mechanism needs to be further strengthened if TCMET is to be promoted and applied during the recovery period of stroke.

Trend of Development
Te characteristic of TCM is holism and treatment based on syndrome diferentiation. TCMET such as Tai Chi, Baduanjin, Daoyin, Yi Jin Jing, six-character tips, Relaxation exercises, Shaolin kung-fu, and Standing pile exercises mentioned in this article refect the advantages of TCM through body adjustment, heart adjustment, and pranayama, which can adjust the motor function, balance and coordination ability, and overall disease resistance and rehabilitation ability of stroke patients from multiple levels and angles, which is consistent with the overall rehabilitation and comprehensive rehabilitation goals of stroke rehabilitation and is worthy of further promotion and application. TCMET has achieved some success in the study of the stroke recovery period. However, there are still several issues that merit further in-depth study. For example, in the design of clinical trials, TCMET is difcult to blind, and most studies use evaluator blinding; the sample size of the trial is too small, and further largesample studies are needed to further confrm the reliability of the data; in terms of inclusion standards, it is difcult for patients with poor motor function and balance function to participate in the trial. Te measurement-efciency relationship of intervention time needs further follow-up and study; there is no completely unifed standard for TCMET intervention during stroke recovery. From the analysis of each subgroup in TCMET, most of them used TCMET combined with other drugs, Western medicine rehabilitation, and other methods, and there were many confounding factors and certain limitations. Tere is relatively insufcient research on safety evaluation and fall prevention; in terms of evaluation standards, most of them are scales, with certain subjectivity; the discussion of mechanism is relatively weak; and further research on the intrinsic characteristics and efect mechanisms of each TCMET, at the molecular level and even deeper levels, needs to be further developed.
In the future, TCMET's prevention and treatment of the stroke recovery period will need to overcome the shortcomings of existing research based on artifcial intelligence and big data technology, combined with diferent TCMET characteristics and the development of diferent stages of multiexercise or partial stereotype integration of unifed standards for TCMET to stroke recovery period research to provide evidence-based medical evidence, multilevel, large sample, multicenter research, and from stroke recovery period to subacute stage transition research, so that more stroke patients can receive timely and early intervention in TCMET treatment. Let this therapy become an efective method for the prevention and treatment of stroke diseases in countries around the world. Te burden of stroke is shared by society, families, and individuals.

Data Availability
All data supporting the fndings of this study are available within the article. 12 Evidence-Based Complementary and Alternative Medicine