INTRODUCTION
With the aging global population, the health status of the elderly has become a critical issue in global public health [1]. Sarcopenia, an age-re-lated geriatric syndrome, is defined by a reduction in skeletal muscle mass, muscle strength, and/or physical function [2]. Approximately 10–16% of global older adults are affected by sarcopenia, which is associated with various adverse health outcomes, including poor surgical prognosis, prolonged hospitalization, and an increased risk of falls and fractures [3]. Consequently, managing sarcopenia and delaying its progression is crucial for healthy aging.
The decline in skeletal muscle mass and functional capacity caused by sarcopenia can lead to gait abnormalities in older adults, potentially resulting in the loss of independence. Cross-sectional studies have shown that the reduction in gait speed associated with sarcopenia may indirect-ly increase dependency on activities of daily living in the elderly [4]. Therefore, improving gait speed is critical for enhancing the quality of life in individuals with sarcopenia. Balance ability is a also a key compo-nent in maintaining a healthy gait. However, with aging, the central ner-vous system's capacity for neuromuscular control deteriorates, leading to progressive balance impairments [5]. Exercise has emerged as a primary non-pharmacological strategy for improving gait and balance abilities.
Although no effective pharmacological treatments for sarcopenia have been identified, exercise is regarded as one of the most appropriate and effective non-pharmacological interventions for managing and delaying the progression of sarcopenia [6,7]. A meta-analysis study has demonstrated that exercise can improve physical performance and muscle strength, but its effects on muscle mass are limited, and the impact on gait speed remains inconsistent [8]. Another meta-analysis found that resistance training and mixed training (resistance training combined with other exercises) can enhance knee extensor strength and gait speed, whereas whole-body vibration training showed minimal effects [9]. In a study comparing the effects of group-based and home-based exercise programs on individuals with sarcopenia, participants engaged in a 24-week exercise regimen, including stretching, strengthening training, balance, and gait training [10]. The group-based program demonstrated su-perior improvements in physical performance compared to the home-based program [10]. However, both exercise modalities effectively enhanced muscle strength and gait speed [10]. Another study investigated the effects of an 8-week kettlebell training program in women with sarcopenia, reporting improvements in the sarcopenia index, grip strength, back strength, and peak expiratory flow [11]. Notably, these benefits persisted even after four weeks of detraining [11]. These studies primarily focused on the effects of resistance or aerobic exercise on sarcopenia, but high-intensity exercise and single-modality programs may make it diffi-cult for older adults to maintain long-term participation. Therefore, se-lecting an exercise modalities that encourages sustained engagement is particularly important in elderly populations.
Tai Chi, a traditional Chinese exercise, is a safe, moderate- to low-intensity aerobic exercise characterized by slow, controlled weight-shifting movements, making it particularly suitable for older adults [12]. Previous studies have shown that Tai Chi can enhance muscle strength and balance, reduce fall frequency, and improve gait in healthy elderly individuals [13,14]. Tai Chi has also been shown to effectively enhance functional fitness in individuals with conditions such as Parkinson's disease [15] and dementia [16]. Studies have reported that individuals with sarcopenia experienced significant improvements in gait speed following 8 weeks [15] or 10 months [17] of Tai Chi training. However, changes in other gait parameters remain unclear in both studies. Therefore, this study aims to investigate the impact of Tai Chi on balance and gait in older adults with sarcopenia.
METHODS
1. Participants
The study included community-dwelling women aged 60 years or older residing X City, H Province, China, who agreed to participate. Based on the sarcopenia criteria defined by the Asian Working Group for Sarcopenia, participants were divided into 3 groups: Tai Chi+normal (T), Tai Chi+sarcopenia (T·S), and Tai Chi+severe sarcopenia (T·SS). Ac-cording to the criteria, sarcopenia is diagnosed when low muscle mass is combined with either reduced muscle strength or physical performance, and it is classified as severe sarcopenia when all three factors are impaired [2]. In this study, sarcopenia was assessed using the following criteria: low muscle mass measured by bioelectrical impedance analysis (BIA) with an appendicular skeletal muscle mass index of <5.7 kg/m2, low hand grip strength (<18 kg), and poor physical performance, defined as ≥12 seconds on the 5-time chair stand test.
Participants were required to meet the following inclusion criteria: female older adults aged between 60 and 80 years, capable of walking in-dependently without assistive devices, willing to sign an informed con-sent form, and actively participate in all study procedures. Additionally, they voluntarily engaged in the prescribed exercise program. Eligible participants underwent three diagnostic tests for sarcopenia. Those who did not meet any of the sarcopenia criteria were assigned to the T group, while those failing two criteria were placed in the T·S group, and those meeting all three criteria were classified into the T·SS group. Participants who failed only one criterion were excluded from the study. A total of 30 eligible subjects were selected and evenly allocated to the three groups (n=10 per group). Preliminary assessments revealed no statistically significant differences in basic physical characteristics among the three groups, aside from the diagnostic criteria (Table 1). Additionally, none of the participants had prior experience with Tai Chi prior to this study.
Table 1.
Characteristics of study participants
2. Diagnosis of sarcopenia
Hand grip strength was used to assess the muscular strength. Participants were seated with their elbows at 90° and their forearms in a neu-tral position. Held the handle of a handgrip dynamometer (CAMRY Digital Hand Dynamometer 210, China) with the second joint of their fingers. Participants squeezed the dynamometer maximally for 3–5 seconds. Each hand was performed twice in trials, with a rest between trials, and the highest value was recorded.
Physical performance was assessed using a 5-chair stand test. Participants were asked to stand up and return to a sitting position five times in a cross with their hands folded in front of their chest. The time required to complete the task was recorded.
Appendicular skeletal muscle mass was measured using bioelectrical impedance analysis. Participants stood barefoot on the body composition analyzer InBody 770 (InBody Co., Ltd., Seoul, Korea) in an upright position, holding the electrodes with both hands. Measurements were taken twice, and the average value was calculated.
3. Bone health measurement
Quantitative ultrasound measurement was used to determine non-dominant side calcaneus bone health. Bone strength was assessed by the bone quality index (BQI), with a lower value indicating poor bone quality. To calculate BQI, broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured by an ultrasonic bone densitometer (OSTEOKJ2000, KeJin, Inc., Nanjing, China). The participant's ankle was disinfected with alcohol, and ultrasound gel was applied to the calaneus. Then, the calcaneus was positioned in front of the probes on both sides and measured for 15 seconds.
4. Isokinetic muscular strength test
The isokinetic muscular strength was assessed by an isokinetic multi-joint system (Prima PLUS, US). Before the experiment, all participants were asked to identify their dominant leg, and measurements were conducted on the dominant side of the knee and ankle. Muscular strength was evaluated by peak torque at 60°/sec with five repetitions. Participants were seated with their upper limbs and thighs secured, ensuring that the axis of rotation was aligned with the lateral side of the knee for knee measurements and with the lateral malleolus for ankle measurements. To ensure familiarity with the test, participants performed 5 to 10 practice repetitions prior to testing. During the assessment, the instructor strongly encouraged participants.
5. Balance ability test
Static balance was evaluated using a force platform (Super Balancing XC-1000, China) to measure center of pressure (COP) movement. Participants stood on the platform with their feet toe positioned 60° apart, both arms were naturally placed alongside the body, and their eyes were closed. Three measurements were conducted, each lasting 10 seconds, and the minimum value was recorded as the result. The velocity, angle, area, and total trajectory length of the COP were calculated as the results. Dynamic balance ability was assessed using the Timed Up-and-Go (TUG) Test. Participants started from a seated position in an arm-chair, stood up, walked 3 meters, turned around, walked back, and sat down. The time taken to complete the entire sequence was recorded.
6. Gait performance test
Gait performance was collected through a motion capture system (NEURON Pro, Perception Neuron, Noitom, Miami, FL, USA) consisting of 17 composed of 17 inertial measurement unit (IMU) sensors at-tached to various anatomical segments (head, shoulders, chest, trunk, upper arms, forearms, hands, thighs, lower legs, and feet). Data were analyzed using Axis Neuron Pro software (Noitom, Miami, FL, USA). Participants performed normal walking along a 10-meter straight path three times while wearing 17 sensors. Step length, gait speed, and double support time were recorded as the outcomes.
7. Tai Chi training intervention
Tai Chi training was performed five times a week for 12 weeks. Each session included a 10-minute warm-up and cool-down exercise were conducted before and after Tai Chi training. The Tai Chi training con-sists of practicing the full 24-form Tai Chi routine (Table 2). Each routine takes approximately 5 minutes. Participants practice twice, rest for 5 minutes, repeat twice, rest for another 5 minutes, and practice twice again. Training took place from 7 to 8 a.m. Professional coaches and ob-servers assisted throughout the process to minimize the risk of exercise injuries. Given that the participants were elderly, the exercise intensity was monitored using the Rate of Perceived Exertion (RPE) scale, maintaining an RPE of 13 (somewhat hard), corresponding to moderate to high intensity, during the Tai Chi training period [18].
Table 2.
Tai Chi exercise routine
8. Statistical analysis
Statistical data analysis was performed using SPSS version 25.0 (IBM, Armonk, NY, USA). Group differences were analyzed using one-way ANOVA with Bonferroni post-hoc tests. Within-group comparisons of pre- and post-measurement values were performed using paired t-tests. Data are expressed as mean±standard error (SE), with statistical signifi-cance set at p<.05.
RESULTS
1. Effects of Tai Chi on bone health
The changes in bone health after 12 weeks of Tai Chi are shown in Fig. 1 and Table 3. Significant improvements in BQI and SOS were observed only in the T and T·S groups following Tai Chi training, with no changes in the T·SS group (Fig. 1A&C, p <.05). Additionally, in SOS, the post- of the T·S group showed a significant difference compared to the T group, while the post- of the T·SS group differed significantly from both the T and TS groups (Fig. 1C, p <.05). Meanwhile, no significant changes were observed in BUA (Fig. 1B).
Fig. 1.
Fig. 1.Changes in bone health parameters before and after the 12-week Tai Chi intervention. (A) Bone Quality Index, (B) Broadband Ultrasound Attenuation, (C) Speed of Sound. T, Tai Chi+normal; T·S, Tai Chi+sarcopenia; T·SS. Tai Chi+severe sarcopenia. All data are presented as mean±SE. * p<.05 compared to pre-treatment;a p<.05 compared to T group;b p<.05 compared to T·S group.
Table 3.
Pre- and post-intervention changes in bone health indicators among groups
| Variables | T (n=10) | T·S (n=10) | T·SS (n=10) | |||
|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | Pre | Post | |
| BQI | 80.03±14.54 | 84.25±13.31* | 74.51±13.83 | 76.51±16.83* | 73.18±15.8 | 73.86±12.15 |
| BUA (dB/MHz) | 70.05±21.46 | 70.15±20.37 | 57.7±18.91 | 56.38±20.66 | 54.07±19.74 | 54.78±19.66 |
| SOS | 1510.84±45.76 | 1636.65±54.34* | 1501.12±30.9 | 1551.12±30.9a* | 1496.89±35.09 | 1489.54±43.23ab |
2. Effects of Tai Chi on isokinetic muscular strength
The changes in lower limb isokinetic strength following 12 weeks of Tai Chi training are shown in Fig. 2 and Table 4. The T and T·S groups improved their knee extensor strength after a 12-week Tai Chi training program (Fig. 2A, p <.05). However, the T·SS group showed no changes (Fig. 2A). Furthermore, there were no significant differences in knee flexor strength in all of the groups (Fig. 2B). No significant changes in ankle joint muscle strength, including both the ankle extensors and flex-ors, were observed following Tai Chi training (Fig. 2C, D).
Fig. 2.
Fig. 2.Changes in lower limb isokinetic muscular strength. (A) Knee Extension Strength, (B) Knee Flexion Strength, (C) Ankle Extension Strength, (D) Ankle Flexion Strength. T, Tai Chi+normal; T·S, Tai Chi+sarcopenia; T·SS, Tai Chi+severe sarcopenia. All data are presented as mean±SE. * p<.05 compared to pre-treatment;a p<.05 compared to T.
Table 4.
Changes in isokinetic muscular strength (Nm/kg)
| Variables | T (n=10) | T·S (n=10) | T·SS (n=10) | ||||
|---|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | Pre | Post | ||
| Knee | Extension | 0.9±0.18 | 0.93±0.16* | 0.75±0.28 | 0.76±0.17a* | 0.71±0.34 | 0.74±0.12a |
| Flexion | 0.61±0.2 | 0.62±0.23 | 0.61±0.19 | 0.62±0.12 | 0.58±0.23 | 0.59±0.21 | |
| Ankle | Extension | 0.24±0.12 | 0.25±0.15 | 0.21±0.06 | 0.22±0.16 | 0.21±0.05 | 0.21±0.07 |
| Flexion | 0.61±0.2 | 0.61±0.23 | 0.62±0.19 | 0.6±0.23 | 0.58±0.23 | 0.54±0.18 | |
3. Effects of Tai Chi on balance ability
The changes in balance ability after 12 weeks of Tai Chi are shown in Fig. 3 and Table 5. Except for the swing angle in the T·SS group, all static balance parameters significantly improved across the three groups compared to pre-training (Fig. 3A-D, p<.05). In the T·S group, swing velocity demonstrated significant differences from the T group both pre-and post-training, while swing angle, periphery area, and total trajectory length showed significant differences before the training but not after. In contrast, the T·SS group exhibited significant differences in swing velocity, swing angle, periphery area, and total trajectory length compared to the T group both pre-and post-training. Furthermore, while there were no significant differences between the T·S and T·SS groups before the intervention, significant differences emerged after the intervention.
Fig. 3.
Fig. 3.Changes in balance ability. (A) Swing velocity, (B) Swing angle, (C) Periphery area, (D) Total trajectory length, (E) Timed Up-and-Go. T, Tai Chi+normal; T·S, Tai Chi+sarcopenia; T·SS, Tai Chi+severe sarcopenia. All data are presented as mean±SE. * p <.05 compared to pre-treatment;a p<.05 compared to T group;b p<.05 compared to T·S group.
Table 5.
Changes in balance ability
| Variables | T (n=10) | T·S (n=10) | T·SS (n=10) | ||||
|---|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | Pre | Post | ||
| Close eyes (double) | Swing velocity (mm/s) | 19.68±3.11 | 16.24±3.02 | 26.18±3.94a | 21.39±3.11a* | 28.39±3.34a | 24.43±2.98ab |
| Swing angle (°) | 1.31±0.23 | 1.22±0.21* | 1.64±0.24a | 1.35±0.28* | 1.77±0.26a | 1.69±0.26ab | |
| Periphery area (mm2) | 123.75±21.54 | 110.78±17.97* | 156.49±21.95a | 123.75±21.54* | 167.43±17.97a | 145.32±21.39ab* | |
| Total trajectory length (mm) | 187.72±23.49 | 177.88±22.58* | 219.89±36.19a | 187.72±23.49* | 231.67±33.42a | 219.18±33.42ab | |
| TUG (sec) | 7.22±0.85 | 6.45±0.81a* | 8.77±1.32a | 7.77±0.81a* | 11.87±1.24ab | 8.12±0.65a* | |
Dynamic balance was assessed using the completion time of the TUG test (Fig. 3E). All groups showed significant improvements in dynamic balance after Tai Chi practice (p <.05). The pre- and post-training of the T·S and T·SS groups were significantly longer than those of the T group. Additionally, while the T·SS group showed significantly longer results than the T·S group before the training, no significant differences were observed between the two groups after the training.
4. Effects of Tai Chi on gait performance
The changes in gait performance after 12 weeks of Tai Chi are shown in Fig. 4 and Table 6. Except for the double support time in the T group, all gait performance parameters showed significant improvements across all groups compared to pre-training (p <.05). Furthermore, step length and gait speed in the T·S and T·SS groups demonstrated significant differences compared to the T group before the training, no significant differences were observed after the training (Fig. 4A, B).
Fig. 4.
Fig. 4.Changes in Gait performance. (A) Gait speed, (B) Step length, (C) Double support time. All data are presented as mean±SE. T, Tai Chi+normal; T·S, Tai Chi+sarcopenia; T·SS, Tai Chi+severe sarcopenia. * p<.05 compared to pre-treatment;a p<.05 compared to T group.
Table 6.
Changes in gait performance
| Variables | T (n=10) | T·S (n=10) | T·SS (n=10) | |||
|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | Pre | Post | |
| Gait speed (m/s) | 1.16±0.15 | 1.18±0.12* | 0.91±0.13a | 1.02±0.11* | 0.82±0.12a | 0.97±0.14a* |
| Step length (m) | 0.65±0.13 | 0.72±0.09* | 0.51±0.07a | 0.54±0.06a* | 0.49±0.06a | 0.53±0.07a* |
| Double support time (s) | 0.24±0.13 | 0.24±0.02 | 0.26±0.03 | 0.24±0.04* | 0.27±0.04 | 0.25±0.03* |
DISCUSSION
Sarcopenia leads to declines in muscle strength, balance ability, and gait performance in older adults, and exercise is widely recognized as an effective intervention for addressing these issues [6]. This study aimed to investigate the effects of Tai Chi, a safe and feasible exercise for older adults, on balance ability and gait performance in older adults with sarcopenia.
After 12 weeks of Tai Chi training, BQI and SOS significantly increased in the T and T·S groups, while no significant changes were observed in the T·SS group (Fig. 1). These results suggest that Tai Chi may have a partial positive effect on bone health. Cheng et al. reported that 48 weeks of Tai Chi training increased lumbar (L2) bone mineral density in postmenopausal women, and this effect persisted for up to 8 weeks after the cessation of exercise [19]. Additionally, a meta-analysis reported that Tai Chi significantly improved SOS compared to non-exercise groups, while no changes were observed in BQI and BUA [20]. Tai Chi enhances muscle contraction and increases muscle strength, particularly in the lower limbs, through its gentle and fluid movements [14]. This improvement in musculoskeletal function contributes to the support of the skeletal system, potentially leading to an increase in bone density [21]. This may explain why only the T and T·S groups showed improvements in bone health in this study, as muscle strength increased only in the T and T·S groups during lower limb strength measurements. Since there are still few studies examining the effects of Tai Chi on the bone health of individuals with sarcopenia, the findings of this study could serve as a basis for future research.
Enhancing lower limb strength is critical in preventing falls among older adults [22]. As individuals age, muscle strength naturally declines; however, exercise is recognized as an effective method for increasing strength [6]. Like previous studies [14,23], in this study, Tai Chi training was shown to improve knee extensor strength in the T and T·S groups (Fig. 2). In contrast, knee flexor, ankle extensor, and ankle flexor strength were maintained. Tai Chi involves maintaining a slightly bent knee position while continuously shifting weight from one leg to the other, which may positively impact lower limb muscles. Due to the relatively weak baseline muscle strength in the T·SS group, participants found it chal-lenging to perform squats during Tai Chi training. Furthermore, to maintain body balance, participants had difficulty in significant shifts in their center of gravity, which may have restricted the effective contraction of the lower limb muscles. Although the T·SS group did not exhibit significant improvements in muscle strength, the maintenance of strength suggests that Tai Chi may still be a valuable exercise for individuals with severe sarcopenia.
Balance ability is a crucial factor that enables older adults to perform daily activities effectively. However, it tends to decline with age and is closely associated with an increased risk of falls and altered gait performance [24]. Balance ability can be categorized into static and dynamic balance [25]. In this study, static balance was assessed by measuring the COP displacement with eyes closed, and the results indicated that Tai Chi improved static balance regardless of the severity of sarcopenia (Fig. 3). Dynamic balance was evaluated using the TUG test, and all groups showed a reduction in completion time, demonstrating that Tai Chi exercise also enhanced dynamic balance (Fig. 3).
Similarly, Zhu et al. (2019) reported that after an 8-week Tai Chi exercise program, patients with sarcopenia exhibited improvements in static balance, as measured with eyes closed, and dynamic balance, as assessed by the TUG test [23]. These improvements may be attributed to the slow and controlled movements, shifts in the center of gravity, and continu-ous joint movements inherent to Tai Chi [26]. The movement characteristics of Tai Chi are characterized by a slower walking speed, greater COP displacement, and significant lateral body movement, resulting in lower stability compared to conventional gait [27]. This low stability pos-es challenges to the body's postural control system, requiring participants to exert greater effort to maintain balance, thereby enhancing their balance ability [27]. Tai Chi has been shown to enhance proprioception, which may further contribute to improvements in balance ability [28].
Gait performance typically declines with age, leading to shorter stride length and slower gait speed [29]. In this study, Tai Chi exercise improved gait gait speed, step length, and double support time, in all groups of older adults with sarcopenia. A particularly noteworthy finding is the improvement in gait speed, which serves as a critical indicator of gait performance [30]. Enhancing gait speed can help reduce the dependency of sarcopenic individuals on activities of daily living [4]. Previous studies have similarly reported that Tai Chi exercise can improve gait performance in older adults [13,31].
The study by Zou et al. (2017) showed that 8 weeks of Tai Chi exercise can reduce the double support time and increase stride length and gait speed in healthy elderly women, which is similar to the results of this study [32]. The decline in physical control and balance leads older adults to adopt a safer and more stable gait pattern, characterized by increased double support time, reduced step length, and slower gait speed [33]. In this study, the observed increase in gait speed may be attributed to longer step length and shorter double support time (Fig. 4). Although no significant improvements in lower limb strength were observed the maintenance of muscle strength and improvements in balance may have contributed to the observed enhancement in gait performance. Tai Chi appears to support preservation of lower limb strength. Overall, Tai Chi enhancement of balance function, and improvement in gait performance, even in older adults with moderate to severe sarcopenia.
These findings suggest that Tai Chi may serve as an effective intervention to delay or attenuate age-related functional deterioration linked to sarcopenia, thereby promoting independent living, enhancing quality of life, and contributing to healthy aging among older adults.
CONCLUSION
This study demonstrated that 12 weeks of Tai Chi had significant positive effects on balance ability and gait performance in female elderly regardless of the degree of sarcopenia, even if there are no improvements in lower limb strength. Tai Chi appears to be an appropriate, safe, and effective form of exercise for some individuals with severe sarcopenia. We suggest future studies should explore the effects of Tai Chi on male patients with sarcopenia.
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