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Year : 2019  |  Volume : 2  |  Issue : 2  |  Page : 88-92

Making Sense of an Ancient Discipline in a Modern Time: How Tai Chi (太极) Practice Benefits the Body–Mind

International Education College, Shanghai University of Traditional Chinese Medicine, Shanghai, China

Date of Web Publication19-Jun-2019

Correspondence Address:
Mr. Meghdad Abdi
International Education College, Shanghai University of Traditional Chinese Medicine, 6th Generation Disciple of Yang Family Taijiquan, Certified Taijiquan Instructor
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/CMAC.CMAC_16_19

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Tai chi(太极) is an ancient Chinese traditional martial art that, today, is also practiced as a graceful and multifaceted form of exercise. It involves a series of movements performed in a slow, focused manner accompanied by deep breathing and expanded awareness of the body, mind, and surrounding environment. There is growing evidence that this mind–body practice has value in treating or preventing many health problems and you can get started even if you are not in top shape or the best of health. This paper is a review of the research that has been conducted internationally on the health-enhancing aspects of Tai Chi practice over the past few years. It is not possible to cover all areas of research in one paper; therefore, three important areas are chosen and discussed, namely, improving balance, strengthening the bones, reducing pain and the rest will be referred to in a future article.

Keywords: Balance, bone strength, Qi(气) , reducing the pain, Tai Chi(太极)

How to cite this article:
Abdi M. Making Sense of an Ancient Discipline in a Modern Time: How Tai Chi (太极) Practice Benefits the Body–Mind. Chin Med Cult 2019;2:88-92

How to cite this URL:
Abdi M. Making Sense of an Ancient Discipline in a Modern Time: How Tai Chi (太极) Practice Benefits the Body–Mind. Chin Med Cult [serial online] 2019 [cited 2021 May 19];2:88-92. Available from: https://www.cmaconweb.org/text.asp?2019/2/2/88/260704

“If you want to know where in the end the purpose lies, it is to increase the longevity and extend one's years, a springtime of youth”

–Song of thirteen postures

  Philosophy, History, and Development of Tai Chi Top

Tai chi(太极)is an ancient Chinese traditional martial art that, today, is also practiced as a graceful and multifaceted form of exercise. It involves a series of movements performed in a slow, focused manner accompanied by deep breathing and expanded awareness of the body, mind, and surrounding environment.

In this low-impact, slow-motion exercise, you go without pausing through a series of motions named after animal movements, i.e., “white crane spreads its wings,” martial arts movements such as “turn the body, separation kick,” Chinese myths like “needle at sea bottom,” or cosmological names as in “Big Deeper.” As you move, you breathe deeply and naturally, focusing your attention – as in some kinds of meditation – on your bodily sensations. Tai chi differs from other types of exercise in several respects. The movements are usually circular and never forced, the muscles are relaxed rather than tensed, the joints are not fully extended or bent, and connective tissues are moderately stretched. Tai chi can be easily adapted for anyone, from the most fit to people confined to wheelchairs or those recovering from surgery.

Before the emergence of Tai Chi Chuan(太极拳) as a form martial art, the concept of Tai Chi existed as an important part of Chinese philosophy for more than a thousand years, as reflected in this famous saying from the Tai Chi classics: “Taiji, born from Wuji, is the mother of Yin-Yang; In movement it divides, at rest it reunites”. In fact, Tai Chi Chuan is a martial art based on Tai Chi philosophy and has deep roots in Chinese traditional culture.

Having this background in mind, we can see that nowadays, Tai Chi is growing as a multifaceted art that attracts people of different interests who benefit from it. One of these aspects is improving health. There is growing evidence that this mind–body practice has value in treating or preventing many health problems and you can get started even if you are not in top shape or the best of health. This paper is a review of the research that has been conducted internationally on the health-enhancing aspects of Tai Chi practice over the past few years. It is not possible to cover all areas of research in one paper; therefore, some important areas are chosen and discussed, and the rest will be referred to in a future article.

  The View of Modern Research Improving Balance Top

The technical definition of balance, or postural stability, is the ability to maintain and control the position and motion of the center of mass of the body relative to the base of support. Several studies have found evidence that Tai Chi can increase balance and stability in all people, especially in older people and people with conditions that affect balance, such as multiple sclerosis and Parkinson's disease; Tai Chi can reduce the risk and fear of falling down too.

Balance and person's relationship to gravity involves many interacting factors, including musculoskeletal (muscle strength and flexibility), sensory perception, neuromuscular coordination or synergy, and cognitive processes. Understanding these components, including how they degrade with age or disease, and understanding how Tai Chi affects them will help you appreciate why Tai Chi is often so effective at improving balance. The musculoskeletal system includes bones, joints, skeletal muscles, tendons, and ligaments. Each person's muscle strength and flexibility, as well as the range of motion of joints, all help keep a person upright and affect his/her balance. In falls (especially among the elderly), the main reasons are significant muscle weakness due to aging, decreased ankle flexibility, and decreased spinal flexibility (especially spinal extension which is the ability to stand up straight).

Tai Chi is a weight-bearing exercise, and it involves a constant shifting of weight from one leg to the other, which facilitates improved dynamic standing balance and strength of the lower extremities (legs, ankles, and feet). Studies show improved lower extremity strength – in particular, knee strength, following Tai Chi training and so Tai Chi has effect on reducing pain and improving physical function and performance in patients with knee osteoarthritis, a condition that is one of the most common joint diseases seen in the elderly. Tai Chi also improves torso and limb flexibility and range of motion, which is an essential component for postural control. This valuable Chinese martial art is widely believed to encourage better posture through body alignments and an emphasis on maintaining a vertical posture with an extended head and trunk position.[1]

Another component related to balance is sensory. As a brief explanation to the role of sensory input, you need to know that brain receives a combination of balance-related sensory signals from your eyes; from pressure sensors in the skin, muscles, and joints; and from the vestibular system located in the inner ear. As we age, the quality of inputs from all three systems declines and several studies have shown that elderly people perform less well in maintaining a standing position than younger people when under conditions of reduced or conflicting sensory inputs.[2]

Tai Chi's continuous, slow, and even tempo facilitates sensory awareness of the speed, force, trajectory, and execution of movements, as well as awareness of the external environment. With Tai Chi, your sensory systems become highly sensitized, which leads to better balance and function. One Hong Kong study compared older Tai Chi practitioners to age-matched nonpractitioners and found that those who practiced Tai Chi scored higher on an instrument measuring overall body awareness. What's more, Tai Chi practitioners had significantly better ability to lean further in most directions without losing their stability.[3]

A more recent study showed that a group of elderly long-term Tai Chi practitioners had improved knee joint proprioception and their limits of stability during weight shifting in stance had expanded; Tai Chi practitioners had a better sense of the position of their ankle and knee joints in space.[4] Hence, Tai Chi may give you more accurate, quicker feedback for balance and posture, which could help prevent falling.

Some studies show that Tai Chi positively helps people who have peripheral neuropathy and experience little sensation in their hands and feet. Reduced sensation in the feet, for example, greatly affects balance. This condition is common among those who have diabetes or people who are undergoing chemotherapy, among others. A nonrandomized trial reported that a 12-week Tai Chi program in diabetic patients who had peripheral neuropathy increased nerve conduction velocities.[5] It is not just legs but the hands as well that become more sensitive through Tai Chi. For example, a study followed sensitivity to touch in a group of people who practiced Tai Chi. The result of this study showed that Tai Chi practitioners, most notably older people, had the equivalent increase in sensitivity seen among blind people who read Braille.[6]

A study carried out in Harvard University, led by Dr. David Krebs, has shown that Tai Chi can help patients who have vestibular-related balance problems. They compared 10 weeks of Tai Chi training with conventional vestibular rehabilitation exercises and realized that overall, Tai Chi more effectively improved dynamic balance control in those patients. It seems that Tai Chi may affect different mechanisms of balance than traditional rehabilitation in patients who have vestibular problems. Thus, Tai Chi may provide an excellent adjunct, synergistic therapy for patients who have medical vestibular disorders.[7] More generally, studies support that Tai Chi improves the ability to compensate when balance-related sensory input is limited or conflicting, and this is what is called improved sensory organization. Studies have shown that during balance testing, Tai Chi practitioners are better equipped to maintain their balance. In fact, some studies show that elderly Tai Chi practitioners attain the same level of balance control as young, healthy individuals during these experimental challenges.[8]

When you do a motion, for example, when you put one step in front of the other, numerous muscles throughout your body must contract and relax in a coordinated fashion, in a process called neuromuscular synergy. As you grow old, the coordination of these related processes may break down, which may put you at more risk of falls. The rich diversity of Tai Chi's movements – the sequencing, timing, and combinations of different muscle groups – provides excellent training for the coordination of neuromuscular patterns. Research supports that Tai Chi can improve your dynamic balance as you move and help you recover from perturbations in balance, for example, when you slip on a wet sidewalk.

Research showed that people who were assigned to intensive Tai Chi training exhibited improved ankle neuromuscular reaction, better coordination of muscle groups, and better overall maintenance of balance. In another group of Tai Chi trainees, Tai Chi improved coordination during the very initial stage of walking (gait initiation) or make the gait faster and more stable.[9]

Another interacting factor in keeping balance is cognition. To explain cognition, you need to know that multiple thought processes interact with the other intrinsic factors to affect your balance. These processes include the fear of falling, planning or anticipating tricky situations (walking in the dark or across ice), and your ability to pay attention to postural control, especially while multitasking (for example, talking on a cell phone while walking at the same time). The fear of falling is an increasing problem as we age and is particularly prevalent in those who have balance disorders or a history of falling. From a traditional Chinese medicine perspective, the anxiety associated with fear of falling creates an energetic imbalance in the body, drawing excessive Qi into the chest and head and weakening the energetic root in the legs, and therefore disturbing your sense of feeling grounded. Many aspects of cognitive function decline with age, and elderly people who have a fear of falling are more likely to be depressed and to restrict their activities, and these factors seem to feed on each other.

It is highly likely that one of the primary ways that Tai Chi improves balance and reduces falls is by reducing the fear of falling and associated anxiety. Ironically, fear of falling is one of the biggest predictors of falls, which means that those who have a history of prior falls or who have impaired balance tend to be less grounded and less aware of themselves and their surrounding environment. Good evidence indicates that Tai Chi reduces the fear of falling, probably because this holistic intervention enhances relaxed, body awareness and provides more confidence from better strength and coordination and improves measures of mobility, social support satisfaction, and quality of life.[10] These benefits well explain why community programs are adopting Tai Chi for balance rehabilitation and fall prevention more and more.

Researchers are studying acceleratingly on coordinating and managing the multiple mind–body components during Tai Chi training – that is, integrated arm and leg moves, continuously changing direction, memorizing sequences, breathing, and postural awareness and inner sensations – may further enhance the handling of concurrent mental tasks during physical activities, such as walking down a flight of steps. For example, studies showed that Tai Chi might help improve older adults' capacity to shift attention between mental and physical tasks.[11]

One of the best aspects of Tai Chi is that all people can practise doing it, from young, healthy to elderly or people with disorders. Due to the simple, smooth, and low-impact nature of movements, Tai Chi is suitable for most, if not all, age groups with or without previous experience in sports activities. Tai Chi can be well adapted for each group, based on the circumstances. For instance, groups of researchers planned different simplified Tai Chi exercise program for older adults. Sitting Tai Chi or wheelchair Tai Chi is another common Tai Chi exercise that is widely applied for people with lower body issues.

Wheelchair-related falls are common in survivors with spinal cord injury (SCI). Improving static sitting balance in survivors with SCI can prevent them from sliding and decrease their risk of falling. Recently, a group of researchers at Shanghai Yangzhi Rehabilitation Hospital assessed the effects of wheelchair Tai Chi practice on balance control and quality of life among SCI survivors. After 6 weeks of Tai Chi training, static sitting balance, handgrip strength, and the psychological domain of quality of life improved significantly in the wheelchair Tai Chi group. Hence, this research suggested that Tai Chi can be a feasible, safe, and effective exercise for SCI survivors.[12] Tai Chi appears to help Parkinson's disease patients improve their balance and motor control. Parkinson's disease is a brain disorder that affects muscle control, causing trembling and stiffness, slowness in walking, and difficulties with balance. These impairments greatly hinder everyday function and quality of life.

Some Parkinson's disease symptoms, such as tremors, respond to drug therapy. But others, like overall balance, do not respond well to medication. Some studies suggest that mind-–body exercises like Tai Chi leads to clinically meaningful improvements in multiple domains of motor function and fall risk among patients with Parkinson disease. Recent findings also suggest that Tai Chi training leads to improvements in mood and quality of life.[13] Moreover, Tai Chi is safe and may provide physical and psychosocial benefits in individuals with multiple sclerosis.[14]

  Strengthening the Bones Top

Bone is a dynamic organ that undergoes remodeling throughout life. Bone density in men weakens with age. Bone density in women generally increases during the first three decades of life. At around age 40 years, bone mineral density (BMD) typically begins to decline, with more rapid changes following menopause, paralleling decrease in estrogen levels. However, continued bone loss in later life may also be related to other factors, including decreased calcium and Vitamin D intake, decreased physical activity, and age-related impairment in bone formation. Low BMD-related fractures are associated with significant long-term impairment, high morbidity rates, and high medical costs.

Osteoporosis is a disabling condition predisposing to fractures in both women and men. Osteoporosis means porous bone. If you have osteoporosis, typically you have low BMD, poor bone quality, and fragile bones. This combination, together with the increased risk of falling among older people, leads to painful fractures and other health problems. Since lifelong drug therapy for this condition is an expensive option with uncertain consequences and potential side effects, nonpharmacologic therapy can be an attractive complementary treatment option for many women. For this reason, guidelines for the treatment of osteopenia include exercise. Most people commonly believe that to have an impact on bone, you need to do a considerable amount of high-intensity resistance and strength training. What's more, many older adults just do not do conventional exercises, either due to health factors or a lack of sustained interest, among other reasons. However, research suggests that lower impact exercises, such as Tai Chi, may reduce rates of bone loss, especially in women with moderately low bone density (osteopenia) or osteoporosis.[15]

Tai Chi classics say the body should feel like “steel wrapped in cotton,” highlighting the image of how strong bones support relaxed muscles and connective tissues. Bones are piezoelectric materials and therefore can generate electrical activity in response to mechanical stress and allow for the delivery of an electrical stimulus that contributes to bone health. Tai Chi produces considerable mechanical stress on the different bones of the body, especially the axial skeleton; besides according to Tai Chi theory, it can move and concentrate Qi toward the bones and this Qi flow can strengthen the bones. These theories might suggest the underlying reasons why Tai Chi is beneficial to bone health and density.

One important source of information comes from studies of long-term Tai Chi practitioners. These studies are important because bone changes slowly; it is difficult to do experimental studies for long periods. One such study in Taiwan compared people who practiced Tai Chi for at least 7 years with age-matched controls in the same community. Those who did Tai Chi had greater bone density at the hip and spine. Another study also showed that the rate of decline in bone density among Tai Chi practitioners was slower than among age-matched controls. One trial observed that BMD at the lumbar spine significantly increased following 10 months of Tai Chi, while in sedentary controls, the BMD decreased.[16],[17] Recently, Chow et al. conducted a randomized trial to evaluate the effect of Tai Chi on prevention of osteoporosis; they observed that Tai Chi is beneficial to BMD and may be a cost-effective and preventive measure of osteoporosis. They also confirmed that beneficial effect is better observed in long-term Tai Chi practice.[18],[19] Collectively, these studies suggest that Tai Chi may reduce multiple fall-related fracture risks, especially in postmenopausal women.

  Reducing the Pain Top

Pain is one of the most prevalent and costly medical conditions and hence a key reason why people go to the doctor and take medication. A staggering number of people experience acute and chronic pain and are diagnosed with pain syndromes. Conventional therapies and medications often do not treat pain adequately; so, many people choose to use complementary alternative medicine, including mind–body exercises. These mind–body therapies include relaxation techniques (deep-breathing exercises, guided imagery, meditation, and progressive muscle relaxation), yoga, Tai Chi, and Qigong.

One of the major mechanisms of pain as explained by traditional Chinese medicine is associated with “stagnation” or “blockages” in the body's flow of Qi. Healing occurs through remobilizing this flow and addressing longer term structural or constitutional imbalances leading to the blockages. Traditional methods employed to treat pain and mobilize Qi include acupuncture, Tui Na, Chinese herbal medicine, Tai Chi, and Qigong. Underlying all these practices is the goal of “moving” Qi. Until recent years, Western physicians widely believed that bed rest, and not movement, was the best prescription for many pain conditions like lower back pain. However, evidence from clinical trials has changed this view to one more in line with traditional Eastern approaches that emphasize keeping things moving. Movement and simple exercises such as stretching, range of motion joint movements, and deep breathing now are prescribed increasingly as effective ways to help decrease pain and integrated into typical rehabilitation programs.[20] Physicians now recommend regular exercise to improve function in people who have chronic ailments, including arthritis and back pain.

Mind–body therapies such as Tai Chi are widely used by people who have back pain, as well as those who have osteoarthritis, fibromyalgia, and rheumatoid arthritis. A growing body of studies suggests that Tai Chi may be effective for easing pain and improving quality of life for these and other pain conditions. These researches are beginning to show how Tai Chi may positively affect musculoskeletal pain conditions, such as by improving strength, flexibility, postural alignment, neuromuscular movement patterns, breathing, and psychological well-being. For example, studies indicate that there is good evidence to suggest Tai Chi as a beneficial method to reduce pain in the management of knee osteoarthritis. Other possible benefits include reduced stiffness, improved function, and enhanced mobility.[21]

Another pain-related condition that is the subject of such mind–body exercise studies is fibromyalgia, a medical condition characterized by chronic widespread pain and a heightened pain response to pressure. Evidence suggests that Tai Chi is an effective modality in fibromyalgia patients not only for pain relief but also for improving physical function and optimizing emotional well-being. A study by Jones et al. showed significant improvement in pain by practicing Tai Chi, and even some studies found that these effect sizes were even larger than those from Food and Drug Administration-approved pharmacotherapy, including antidepressants, gabapentinoid, and milnacipran.[22] More recently, nonrandomized studies have demonstrated the decreasing of the levels of acute pain in patients who participated in a course of Tai Chi.[23]

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  References Top

Lu X, Hui-Chan CW, Tsang WW. Effects of Tai Chi training on arterial compliance and muscle strength in female seniors: A randomized clinical trial. Eur J Prev Cardiol 2013;20:238-45.  Back to cited text no. 1
Shumway-Cook A, Woollacott M. Motor Control: Translating Research into Clinical Practice. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2011.  Back to cited text no. 2
Gyllensten AL, Hui-Chan CW, Tsang WW. Stability limits, single-leg jump, and body awareness in older Tai Chi practitioners. Arch Phys Med Rehabil 2010;91:215-20.  Back to cited text no. 3
Zou L, Han J, Li C, Yeung AS, Hui SS, Tsang WW, et al. Effects of Tai Chi on lower limb proprioception in adults aged over 55: A systematic review and meta-analysis. Arch Phys Med Rehabil 2018. pii: S0003-9993(18)30932-8.  Back to cited text no. 4
Hung JW, Liou CW, Wang PW, Yeh SH, Lin LW, Lo SK, et al. Effect of 12-week Tai Chi Chuan exercise on peripheral nerve modulation in patients with type 2 diabetes mellitus. J Rehabil Med 2009;41:924-9.  Back to cited text no. 5
Kerr CE, Shaw JR, Wasserman RH, Chen VW, Kanojia A, Bayer T, et al. Tactile acuity in experienced Tai Chi practitioners: Evidence for use dependent plasticity as an effect of sensory-attentional training. Exp Brain Res 2008;188:317-22.  Back to cited text no. 6
McGibbon CA, Krebs DE, Wolf SL, Wayne PM, Scarborough DM, Parker SW, et al. Tai Chi and vestibular rehabilitation effects on gaze and whole-body stability. J Vestib Res 2004;14:467-78.  Back to cited text no. 7
Tsang WW, Hui-Chan CW. Standing balance after vestibular stimulation in Tai Chi-practicing and nonpracticing healthy older adults. Arch Phys Med Rehabil 2006;87:546-53.  Back to cited text no. 8
Wayne PM, Furest ML. The Harvard Medical School Guide to Tai Chi: 12 Weeks to a Healthy Body, Strong. Shambhala Publications, Inc.; Boston, Massachusetts, 2013.  Back to cited text no. 9
Huang TT, Yang LH, Liu CY. Reducing the fear of falling among community-dwelling elderly adults through cognitive-behavioural strategies and intense Tai Chi exercise: A randomized controlled trial. J Adv Nurs 2011;67:961-71.  Back to cited text no. 10
Miller S, Taylor-Piliae RE. The association between Tai Chi exercise and safe driving performance among older adults: An observational study. J Sport Health Sci 2018;7:83-94.  Back to cited text no. 11
Qi Y, Zhang X, Zhao Y, Xie H, Shen X, Niu W, et al. The effect of wheelchair Tai Chi on balance control and quality of life among survivors of spinal cord injuries: A randomized controlled trial. Complement Ther Clin Pract 2018;33:7-11.  Back to cited text no. 12
Song R, Grabowska W, Park M, Osypiuk K, Vergara-Diaz GP, Bonato P, et al. The impact of Tai Chi and qigong mind-body exercises on motor and non-motor function and quality of life in Parkinson's disease: A systematic review and meta-analysis. Parkinsonism Relat Disord 2017;41:3-13.  Back to cited text no. 13
Taylor E, Taylor-Piliae RE. The effects of Tai Chi on physical and psychosocial function among persons with multiple sclerosis: A systematic review. Complement Ther Med 2017;31:100-8.  Back to cited text no. 14
Liu F, Wang S. Effect of Tai Chi on bone mineral density in postmenopausal women: A systematic review and meta-analysis of randomized control trials. J Chin Med Assoc 2017;80:790-5.  Back to cited text no. 15
Nguyen VH. Osteoporosis prevention and osteoporosis exercise in community-based public health programs. Osteoporos Sarcopenia 2017;3:18-31.  Back to cited text no. 16
Prince DZ, Bartels MN. Exercise recommendations for older adults for prevention of disability. In: Geriatric Rehabilitation Ch.14, Elsevier Inc. 2018. p. 181-93.  Back to cited text no. 17
Chow TH, Lee BY, Ang AB, Cheung VY, Ho MM, Takemura S, et al. The effect of Chinese martial arts Tai Chi Chuan on prevention of osteoporosis: A systematic review. J Orthop Translat 2018;12:74-84.  Back to cited text no. 18
Daly RM, Dalla Via J, Duckham RL, Fraser SF, Helge EW. Exercise for the prevention of osteoporosis in postmenopausal women: An evidence-based guide to the optimal prescription. Braz J Phys Ther 2018. pii: S1413-3555 (18) 30632-4.  Back to cited text no. 19
Corey SM, Vizzard MA, Bouffard NA, Badger GJ, Langevin HM. Stretching of the back improves gait, mechanical sensitivity and connective tissue inflammation in a rodent model. PLoS One 2012;7:e29831.  Back to cited text no. 20
Lü J, Huang L, Wu X, Fu W, Liu Y. Effect of Tai Ji Quan training on self-reported sleep quality in elderly chinese women with knee osteoarthritis: A randomized controlled trail. Sleep Med 2017;33:70-5.  Back to cited text no. 21
Jones KD, Sherman CA, Mist SD, Carson JW, Bennett RM, Li F, et al. Arandomized controlled trial of 8-form Tai Chi improves symptoms and functional mobility in fibromyalgia patients. Clin Rheumatol 2012;31:1205-14.  Back to cited text no. 22
Segura-Jiménez V, Romero-Zurita A, Carbonell-Baeza A, Aparicio VA, Ruiz JR, Delgado-Fernández M, et al. Effectiveness of Tai-Chi for decreasing acute pain in fibromyalgia patients. Int J Sports Med 2014;35:418-23.  Back to cited text no. 23

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