Taichi is medicine: Effects of Taichi exercise on knee fitness and psychological health in older adults with knee osteoarthritis (KOA): A randomized controlled trial

Abstract

Background:

Knee osteoarthritis (KOA) negatively affects quality of life in older adults, leading to reduced mobility and psychological issues such as depression and anxiety. Taichi, a traditional mind-body practice, may offer therapeutic benefits for this population.

Methods:

A structured Taichi intervention was implemented among older adults with KOA. Pre- and post-intervention assessments evaluated knee function, lower limb strength, balance, and psychological outcomes, including depression, anxiety, and stress. Paired t-tests were used to analyze changes.

Results:

This study revealed that The Taichi group showed a statistically significant improvement in knee function (mean difference = 21.6 points, 95% CI: 17.3–25.9, P = .001, Cohen d = 1.87), lower limb strength (mean difference = 24.4 kg, 95% CI: 16.5–32.2, P = .001, d = 1.01), and balance (mean difference = 12.6 points, 95% CI: 2.8–22.3, P = .014, d = 1.01). Psychological outcomes also improved significantly in the intervention group: depression (mean difference = –2.70, 95% CI: –3.71 to –1.69, P = .001, d = 1.06), anxiety (mean difference = –2.28, 95% CI: –3.26 to –1.30, P = .001, d = 0.75), and stress (mean difference = –2.79, 95% CI: –5.19 to –0.39, P = .025, d = 0.61).

Conclusion:

These findings suggest Taichi as a non-pharmacological intervention for improving both physical and psychological outcomes in older adults with KOA. As a holistic mind-body therapy, Taichi presents a promising approach to enhancing functional ability and mental well-being in this population, reinforcing the concept that Taichi is Medicine.

1. Introduction

Knee osteoarthritis (KOA) is a disease that significantly affects patients’ quality of life, with a complex pathophysiology that includes degeneration of cartilage and subchondral bone, synovitis, and associations with mechanical load, inflammation, metabolic factors, and so on.^[1] It is one of the leading causes of functional disability among KOA patients.^[2] Currently, the global prevalence of KOA is 4711.84 per 100,000 (4.90%) people for both sexes, 5838.45 per 100,000 (6.00%) for females, and 3592.35 per 100,000 (3.78%) for males. The global incidence of KOA is 381.4 per 100,000 (0.07%) people for both sexes, 454.46 per 100,000 (0.09%) for females, and 308.8 per 100,000 (0.06%) for males.^[3] KOA can lead to joint impairment, creaking, stiffness, limited movement, increased pain, and a higher risk of falling.^[4] In addition to causing physical pain and dysfunction, KOA also leads to a range of psychological disorders, such as depression, anxiety, and stress.^[5] KOA is a complex, multifactorial disease involving the interplay of mechanical, inflammatory, and metabolic factors.^[6] Mechanically, joint degeneration is often driven by abnormal loading patterns, repetitive stress, and muscle weakness, which contribute to cartilage degradation and bone remodeling.^[7,8] Inflammatory mechanisms, such as synovitis and the upregulation of pro-inflammatory cytokines (e.g., IL-1β, TNF-α), also play a key role in pain sensitization and disease progression.^[9,10] Moreover, metabolic factors like obesity also contribute to mechanical joint overload and metabolic dysregulation, heightens the risk of developing OA.^[11] Consequently, KOA poses a substantial burden not only on affected individuals but also on their families and the healthcare system.

Currently, the pathogenesis of KOA remains controversial, leading to a diverse array of treatment approaches in clinical practice without a unified standard. Effective treatment modalities are still under exploration. The recommended foundational therapies of KOA encompass a wide range of therapies, including health education, surgical interventions, medications, exercise prescription, physical agent modalities, and patient education.^[12] Among these, exercise therapy is strongly endorsed for all KOA patients due to its efficacy in alleviating symptoms, enhancing physical function, and improving quality of life.^[13] Common types of exercise used in the treatment of KOA include resistance training, aerobic exercise, neuromuscular training, and mind-body exercises.^[14] A recent systematic review and meta-analysis of 17 randomized controlled trials (RCTs) revealed that aerobic exercise and mind-body approaches may be the most effective strategies for reducing pain and improving joint function in these patients.^[15]

As a classic oriental mind body exercise, Taichi is an all-age applicable, low-cost, space-saving and more enjoyable strategy, it has gained favorable acceptance in both Eastern and Western societies.^[16] Taichi has various physical and mental benefits, and can be used as an alternative medicine for serious diseases such as cardiovascular health, osteoporosis, rheumatic arthritis, knee arthritis, psychoneuroimmunology, diabetes mellitus, metabolic disorders, and so on.^[17] Currently, a young scholar, Dr Wang, has proposed a new conceptual model integrating Taichi practice with health promotion, termed “Taichi is Medicine” (TIM). This model is grounded in the core principle of dynamic balance and extends the application of Taichi to encompass physical, mental, and psychosocial (or spiritual-social) dimensions of health.^[18] With its mild-to-moderate aerobic intensity and sequence of gentle, low-impact, and coordinated movements, Taichi is often recommended for older adults.^[19,20] Over past decades, some experts have investigated the effectiveness of Taichi on KOA patients’ health. For example, Kang’s team claimed that after 36 weeks of Taichi exercise, KOA patients showed significant improvements in symptoms, physical fitness, and health status indicators.^[21] However, no studies have specifically focused on the mental outcomes of Taichi for elder with KOA. In addition, a recently overview of systematic reviews of the effectiveness of Taichi for KOA indicated that the overall quality of evidence and methodological rigor of past studies was generally unsatisfactory.^[22] Thus, the further research regarding taichi and elderly individuals with KOA is critically needed. This study aims to evaluate the effects of a 12-week Taichi intervention on knee pain, function, balance, and psychological health in patients with KOA through a RCT. Additionally, the study will explore the potential mechanisms underlying these effects.

2. Methods

2.1. Research design

The aim of this study is to evaluate the effectiveness of Taichi exercise on knee function and psychological health in elderly individuals with KOA. To ensure the reliability of the findings, a RCT design was employed. A total of 46 eligible participants were recruited and randomly assigned to either the Taichi exercise group or the control group. Both groups underwent assessments before and after the intervention, conducted at the beginning and end of the trial. This study design allows for a robust comparison of outcomes between the intervention and control groups, providing high-quality evidence on the impact of Taichi on knee health and psychological well-being in this population.

2.2. Sample

In Xian’an District, Xianning City, Hubei Province, China, patients with KOA will be recruited based on the diagnostic criteria outlined in the Diagnosis and Treatment Guide of Osteoarthritis by the Chinese Rheumatology Association.^[23] The criteria include: The criteria include: recurrent knee pain within the past month; X-ray findings (in standing or weight-bearing positions) showing joint space narrowing, subchondral bone sclerosis, and/or cystic changes, along with osteophyte formation at the joint margins; age ≥ 50 years; morning stiffness lasting ≤30 minutes; and presence of crepitus during movement. A diagnosis of KOA is confirmed if criterion (1) is met in combination with any two of criteria (2), (3), (4), or (5).

Inclusion criteria: Age between 45 and 70 years; Presence of pain symptoms for more than one month; and Ability to participate in exercise and willingness to complete evaluation tests. Exclusion criteria: Diagnosed with rheumatoid arthritis or infectious arthritis; Presence of clear contraindications to exercise, such as severe diabetes or cardiovascular disease; History of joint replacement surgery or presence of severe joint deformities; and History of intra-articular injections in the knee within the past 3 months;Currently receiving or having previously received alternative therapies or exercise interventions such as Taichi, yoga, or qigong. Withdrawal criteria: Participants who do not adhere to the treatment protocol after enrollment; Participants who withdraw from the study before completion; and Participants experiencing serious adverse reactions that make continued participation inadvisable.

2.3. Sample size

This study is a RCT that building upon previous research on exercise interventions for KOA.^[24] Using the computer software G*Power 3.1.8, we estimated the required sample size based on outcomes from the visual analog scale. To achieve a statistical power of 90%, with a significance level of 0.05, an effect size of 0.60, a mean difference of 1.57, and a standard deviation of 2.61, the minimum required sample size was 32 participants. Accounting for a 10% dropout rate, the overall sample size was adjusted to a minimum of 42 participants (N1 = N2 = 21). Based on the actual enrollment of volunteers for this study, a total of 46 participants with KOA were included. Participants were randomly assigned to either the control group or the Taichi group using a random number table.

2.4. Randomisation and blinding

Participants were randomly assigned to either the Taichi intervention group or the control group in a 1:1 allocation ratio. The random allocation sequence was generated using a computer-generated random number table by an independent statistician not involved in the study (CONSORT). No blocking or stratification was used.

To ensure allocation concealment, sequentially numbered, opaque, sealed envelopes were prepared by a research assistant who was not involved in the enrollment, intervention, or assessment procedures. After obtaining informed consent and completing baseline assessments, participants were assigned to groups by opening the next envelope in sequence. The enrollment of participants was conducted by the study coordinator, and group assignments were carried out by a separate staff member.

Due to the nature of the intervention, participants and instructors could not be blinded. However, all outcome assessments were conducted by trained evaluators who were blinded to group assignments. The control group received no structured physical activity, while the intervention group participated in supervised Taichi sessions; thus, the 2 conditions were not similar in appearance or delivery. While the inability to blind participants may introduce performance bias, blinding of outcome assessors was implemented to reduce detection bias.

2.5. Protocol of exercise intervention

Participants in the Taichi group received an 8-week intervention, consisting of 4 sessions per week, each lasting 40 minutes. Each session included a 5-minute warm-up, 30 minutes of Taichi practice, and a 5-minute cool-down and relaxation period. The exercise protocol was based on the 24-form Simplified Taijiquan, known for its structured, low-impact movements and wide accessibility, especially among older populations. This form was chosen due to its suitability for individuals with reduced mobility and its effectiveness in promoting balance and joint health. Details of the 24-form can be accessed online or by contacting the corresponding author, Dr Wang (wangfeng@fsskj.upsi.edu.my). All sessions were led by a professional, certified Taichi coach accompanied by an assistant. The instructors were trained in therapeutic applications of Taichi and provided close supervision to ensure safe and standardized practice.

To control the intensity and ensure appropriateness for older adults with KOA: Instructors continuously observed participants for signs of overexertion and provided individual movement modifications when needed. Participants were instructed to maintain a light level of exertion, corresponding to a score of 9 to 11 on Borg 15-point rating of perceived exertion scale, which ranges from 6 (no exertion) to 20 (maximal exertion).^[25] Emphasis was placed on slow, smooth, and continuous movement, deep breathing, and upright posture, reflecting the traditional Yang-style characteristics. The program followed a progressive structure, gradually increasing movement complexity while maintaining low physical intensity throughout.

Participants in the control group were instructed to maintain their ordinary lifestyle, which included continuing their typical daily routines without engaging in any new or structured physical activity, including Taichi or other exercise programs. They were not provided with any exercise or KOA-specific education, health counseling, or intervention during the study period, to serve as a true comparison for the Taichi intervention.

To minimize potential confounding factors: Control participants were asked to refrain from initiating any new physiotherapy, rehabilitation, or exercise regimens throughout the 8-week study. They were contacted weekly to monitor compliance and confirm that no significant changes in their activity levels or treatments occurred. All participants, including those in the control group, were informed that they could access KOA management resources after study completion if desired.

2.6. Measurement and instruments

For knee-based fitness, the researcher selected knee function, low limb force, and balance as the variables. For the psychological health, the researcher selected depression, anxiety, as well as stress as the variables.

The instrument used to assess knee function is Lysholm knee scoring scale, it is one of the most frequently used assessment tools for the results of ACL reconstruction even though it only measures activities of daily living. Eight factors are rated to produce an overall score on a point scale of 0 to 100. Scores are classified as follows: “excellent” for 95 to 100 points; “good” for 84 to 94 points, “fair” for 65 to 83 points, or “poor” for <65 points. The factors of limp, support, and locking are worth a potential of 23 points; pain and instability, 25 points each; swelling and stair climbing, 10 points each; and squatting, 5 points.^[26] Past studies have confirmed the validity and reliability of this scale for knee function.^[27] Isometric leg curl tests were conducted using a dynamometer to assess lower limb strength. This testing method offers several advantages, including high safety, ease of operation, and low cost, making it suitable for evaluating lower body strength or overall strength.^[28] It has been applied in various contexts, including clinical assessments, scientific research, and physical fitness evaluations.^[29] During the assessment, participants were instructed to grip the handles with their arms fully extended and perpendicular to the ground, maintaining an upright posture. The hip flexion angle was set at 60°, and the knee flexion angle at 90°. Participants then exerted force through isometric contractions of the lower limbs, and the maximum reading on the dynamometer (in kg) was recorded. Each participant underwent 3 trials, with the best score taken as the result. The Y Balance Test (YBT) utilizes a composite score (in percentage) to assess the dynamic balance capabilities of participants. YBT is commonly employed to evaluate the stability of both upper and lower limbs, assess injury risk, identify functional deficiencies post-injury, monitor rehabilitation progress, and analyze neuromuscular characteristics.^[30] It has demonstrated strong reliability and validity across both adult and elderly populations.^[31] During the test, participants stand on one leg behind a designated line while the other leg reaches forward, backward-inward, and backward-outward to measure the distance (in centimeters) traveled in each direction. Participants’ leg length is also recorded (in centimeters). The composite score (%) is calculated as the average of the distances reached in each direction divided by the leg length, multiplied by 100.

The instrument for depression, anxiety and stress was Depression Anxiety and Stress Scale (DASS-21). It was utilized to assess the psychological health levels of participants. This scale originally developed by Lovibond et al in 1995. The DASS-21 simplifies the original 42 items down to 21, encompassing 3 dimensions: depression, anxiety, and stress, with each dimension consisting of 7 items.^[32] A current study has confirmed that with Cronbach’s alpha for the internal consistency reliability of the simplified Chinese version of the DASS-21 was 0.909, and Cronbach’s alpha for the internal consistency reliability of the subscales were 0.709 to 0.810.^[33] It verified that DASS-21 is an effective tool for evaluating depression, anxiety, and stress among adult residents in mainland China. The DASS-21 employs a 4-point Likert scale for scoring, ranging from 0 to 3 (0 indicating “does not apply to me at all”; 1 for “applies to me to some degree, or some of the time”; 2 for “applies to me very much, or most of the time”; and 3 for “applies to me most of the time”). Higher scores reflect more severe negative emotional symptoms.^[34]

Besides, no additional secondary outcomes such as quality of life or self-reported pain were measured in this study. The selection of outcome measures was intentionally focused on core domains of physical function (knee fitness, strength, balance) and psychological health (depression, anxiety, stress), which were considered most relevant to the aims and time frame of the intervention.

2.7. Procedure

Initially, 46 eligible volunteers were enrolled in this trial. Participants were then randomly assigned to either the Taichi exercise group or the control group, with each group consisting of 23 patients. However, during the study, the Taichi exercise group experienced a loss of 6 participants (2 sought additional treatment, 2 moved to another city, 1 underwent surgery, and 1 passed away), while the control group lost 4 participants (3 sought additional treatment and 1 moved to another city). Ultimately, 17 participants from the Taichi exercise group and 19 from the control group completed the post-test assessments and were included in the data analysis. The details can be found in Figure 1 as below:

Figure 1.

Following diagram.

2.8. Data analysis

Statistical analyses were performed using SPSS version 26. For normally distributed continuous data, results are presented as means ± standard deviations (x ± s). Differences between the control group and the taichi intervention group, both pre- and post-intervention, were assessed using independent t-tests and repeated measures two-way analysis of variance (ANOVA) to evaluate within-group and between-group differences. For data that did not conform to a normal distribution, results are expressed as medians with interquartile ranges (M [P25, P75]). The Mann–Whitney U test was employed to analyze these non-normally distributed variables. Statistical significance was set at P < .05, indicating a meaningful difference between the groups.

2.9. Ethical concerns

This study received approval from the Ethics Committee of the School of Physical Education at Hubei University of Science and Technology (No: HBUST-SPE-20210913). All participants provided informed consent and signed consent forms, indicating their understanding of the study procedures and their voluntary participation.

3. Results

3.1. Demographics

According to the Table 1, the demographic of patients was exampled as below. More female participants than male involved in the trial (59% participants in Taichi group and 68% participants in control group are female patients). The average age of patients is 57.4 ± 6.5 for Taichi group and 58.6 ± 7.2 for control group. Additionally, the patients ‘BMI is 29.2 ± 3.4 and 28.7 ± 3.6 for Taichi and control group. Obviously, there were no significant differences in gender, age, as well as BMI between the 2 groups.

Table 1.

Demographic (n = 36).

	Gender		Ages	BMI
	Male	Female
Taichi group	7 (41%)	10 (59%)	57.4 ± 6.5	29.2 ± 3.4
Control group	6 (32%)	13 (68%)	58.6 ± 7.2	28.7 ± 3.6

3.2. Outcomes of knee fitness

The outcomes of the knee-based fitness intervention are presented in Table 2 and Figure 2, demonstrating statistically and clinically significant improvements in the Taichi group compared to the control group across knee function, lower limb strength, and balance.

Table 2.

Outcomes of knee-based fitness (n = 36).

Groups	Knee function			Low limb force			Balance
	Pretest	Posttest	P	Pretest	Posttest	P	Pretest	Posttest	P
Taichi	71.5 ± 3.7	93.1 ± 2.6	.001*	63.8 ± 24.5	88.2 ± 25.8	.001*	76.8 ± 6.4	89.4 ± 5.5	.014*
Control	72.4 ± 3.2	72.8 ± 2.4	.744	64.1 ± 23.3	65.6 ± 23.7	.813	76.2 ± 5.8	76.7 ± 5.1	.724

Scores for knee function and balance, kg for low limb force.

*Statistically significant.

Figure 2.

Outcomes of knee fitness.

Knee function significantly improved in the Taichi group from a pretest score of 71.5 ± 3.7 to a posttest score of 93.1 ± 2.6 (P = .001), with a mean difference of 21.6 points (95% CI: 17.3–25.9; Cohen d = 1.87), indicating a large effect size. The control group showed no significant change (pretest: 72.4 ± 3.2; posttest: 72.8 ± 2.4; P = .744).

Lower limb strength improved significantly in the Taichi group from 63.8 ± 24.5 kg at baseline to 88.2 ± 25.8 kg post-intervention (P = .001), with a mean difference of 24.4 kg (95% CI: 16.5–32.2; Cohen d = 1.01). The control group showed no significant improvement (pretest: 64.1 ± 23.3 kg; posttest: 65.6 ± 23.7 kg; P = .813).

Balance also significantly increased in the Taichi group, from 76.8 ± 6.4 to 89.4 ± 5.5 (P = .014), with a mean difference of 12.6 points (95% CI: 2.8–22.3; Cohen d = 1.01). The control group showed no meaningful change (pretest: 76.2 ± 5.8; posttest: 76.7 ± 5.1; P = .724).

These findings support the positive and substantial effects of Taichi on physical functional outcomes in older adults with KOA, while the control group experienced no significant changes.

3.3. Outcomes of psychological health

Psychological health was assessed using the Depression Anxiety and Stress Scale (DASS-21), measuring depression, anxiety, and stress. The results are presented in Table 3 and Figure 3.

Table 3.

Outcomes of psychological health (n = 36).

Groups	Depression			Anxiety			Stress
	Pretest	Posttest	P	Pretest	Posttest	P	Pretest	Posttest	P
Taichi	2.87 ± 3.4	0.17 ± 2.3	.001*	4.26 ± 2.7	1.98 ± 3.3	.001*	7.17 ± 5.4	4.38 ± 3.9	.025*
Control	2.75 ± 2.8	2.83 ± 4.5	.874	4.43 ± 3.1	4.55 ± 3.7	.975	6.98 ± 4.8	7.12 ± 4.5	.796

Scores for all variables.

*Statistically significant.

Figure 3.

Outcomes of psychological health.

Depression levels significantly decreased in the Taichi group from 2.87 ± 3.4 to 0.17 ± 2.3 (P = .001), with a mean difference of–2.70 (95% CI: –3.71 to –1.69; Cohen d = 1.06). The control group showed no significant change (pretest: 2.75 ± 2.8; posttest: 2.83 ± 4.5; P = .874).

Anxiety scores in the Taichi group declined significantly from 4.26 ± 2.7 to 1.98 ± 3.3 (P = .001), with a mean difference of–2.28 (95% CI: –3.26 to –1.30; Cohen d = 0.75). The control group showed minimal change (pretest: 4.43 ± 3.1; posttest: 4.55 ± 3.7; P = .975).

Stress levels decreased in the Taichi group from 7.17 ± 5.4 to 4.38 ± 3.9 (P = .025), with a mean difference of –2.79 (95% CI: –5.19 to –0.39; Cohen d = 0.61). The control group did not show significant change (pretest: 6.98 ± 4.8; posttest: 7.12 ± 4.5; P = .796).

In summary, the Taichi intervention significantly improved psychological well-being by reducing symptoms of depression, anxiety, and stress, while the control group did not experience notable changes in any of these domains.

4. Discussion

Consistent with current studies,^[22] the findings of this study demonstrate that an 8-week Taichi exercise program significantly improved knee based fitness and psychological health in elderly individuals with KOA.

The proper functioning of joints relies heavily on correct biomechanical alignment.^[35] Taichi emphasizes key postural elements such as “sinking, inward rotation, and alignment of the head and spine,” which promote proper joint alignment and balanced tension along the myofascial meridians. Through Taichi practice, the alignment of the hip, knee, and ankle joints is optimized, enabling external forces, such as gravity and applied pressure, to be efficiently transmitted through the bones.^[36] Taichi can reduce abnormal localized stress by improving body composition,^[37] which is a significant contributor to KOA pain. Research indicates that improper biomechanical loading on the knee joint leads to cartilage wear and subchondral bone damage, increasing localized joint stress, which can cause trabecular fractures, inflammation in adjacent tissues, and nociceptor activation, ultimately resulting in pain.^[5,7] By correcting improper joint alignment and movement patterns, Taichi reduces abnormal joint stress, lowering the risk of secondary damage to cartilage and subchondral bone while creating a more favorable biomechanical environment for self-repair.^[38] Additionally, the stress stimulation provided by Taichi improves local circulation, reduces inflammation, and promotes the healing of joint surfaces and bone health.^[14] This leads to substantial improvements in clinical symptoms and reduces the risk of recurrent knee injuries. The crouched posture and relaxation techniques inherent in Taichi also strengthen the lower limb muscles, further enhancing knee stability.^[39]

Balance is another critical factor in KOA progression, with knee proprioception and muscle strength being inversely related. A decline in these factors contributes to reduced knee stability and balance.^[14] Dynamic balance, a core element of Taichi practice,^[18] involves multi-directional stress on the joints, which prompts the body to recruit additional muscle groups to maintain balance.^[21] This process not only enhances neuromuscular control but also strengthens the spiral chains and muscles surrounding the knee joint, improving both knee stability and core strength in patients.

The psychological improvements observed in this study align with previous research highlighting the mental health benefits of Taichi across various populations, including older adults and individuals with chronic conditions.^[39–41] The findings suggest that Taichi, in addition to its physical benefits for knee function, plays a significant role in enhancing mental well-being in elderly KOA patients.

One potential explanation for these psychological benefits lies in the mind-body connection inherent in Taichi practice.^[42] The slow, deliberate movements, combined with deep breathing and mental focus, foster relaxation and mindfulness, which may reduce the psychological stress response and alleviate anxiety and depression.^[39] Studies have shown that mindfulness-based practices can reduce cortisol levels a hormone linked to stress and improve emotional regulation.^[43]

The social aspect of group Taichi practice may also contribute to the observed improvements in psychological health. Participating in a structured, group-based exercise program can provide social support, reduce feelings of isolation, and improve overall mood.^[44] Social interaction and a sense of community are known to have protective effects against depression and anxiety, especially in elderly populations.^[45] This is supported by previous studies demonstrating that group physical activity interventions often yield better psychological outcomes than solitary exercises.^[46]

The reduction in stress, anxiety, and depression can also be attributed to the physiological effects of exercise. Although gentle, Taichi movements engage the parasympathetic nervous system, promoting relaxation and reducing sympathetic nervous system activity, which is associated with the body’s stress response.^[47] This balancing of the autonomic nervous system may help explain the reduction in stress-related symptoms. Moreover, regular physical activity has been shown to boost the production of endorphins, serotonin, and dopamine, neurotransmitters that play a crucial role in regulating mood and emotional well-being.^[48]

To summary, the present study highlights the comprehensive benefits of Taichi for elderly individuals with KOA. Not only does it improve physical outcomes, such as knee function and stability, but it also has a profound impact on mental health, significantly reducing depression, anxiety, and stress. The potential mechanisms underlying these psychological improvements include enhanced mindfulness, social interaction, improved autonomic balance, and increased production of mood-regulating neurotransmitters. Future research should further explore these mechanisms and investigate the long-term effects of Taichi on psychological health in this population.

4.1. Limitations

Although statistically significant effects were observed, the relatively small final sample size (n = 36) and the dropout rate may limit the power of the study and the generalizability of the findings. With a smaller sample, the study may have been underpowered to detect smaller or moderate effects, particularly for secondary outcomes. In addition, the risk of attrition bias increases with high dropout rates, as those who completed the intervention may differ systematically from those who withdrew.

This study used a per-protocol analysis due to incomplete follow-up data for participants who dropped out. As a result, an intention-to-treat (ITT) analysis was not feasible. We acknowledge that the absence of ITT analysis may overestimate the intervention’s effect and limit the robustness of the findings. Future studies with larger samples and full ITT analysis are recommended to validate these results.

Another limitation of this study is the absence of an attention-matched control intervention. While the Taichi group participated in instructor-led sessions that may have provided therapeutic benefits beyond the physical activity (e.g., social interaction, increased engagement), the control group continued their usual routine without structured attention. This difference in contact time and engagement may have introduced performance bias and contributed to improved psychological outcomes independently of the Taichi practice. Future studies should consider including an active control group receiving a comparable level of attention to better isolate the specific effects of Taichi.

4.2. Adverse events and safety

No adverse events or safety concerns were reported by participants in either the Taichi intervention group or the control group throughout the study period. All participants tolerated the intervention well, and no injuries or exacerbation of KOA symptoms were observed.

5. Conclusion

The findings from this study indicate that 8 weeks of Taichi exercise significantly improve knee function, lower limb strength, and balance, while also reducing symptoms of depression, anxiety, and stress in elderly individuals with KOA. These results suggest that Taichi offers substantial benefits for both knee-based fitness and psychological health in this population. Given these comprehensive effects, Taichi may serve as a highly effective non-pharmacological intervention to mitigate the physical impairments and emotional burdens associated with KOA, offering a holistic approach to improving quality of life in elderly patients.

Acknowledgments

We sincerely thank all participants who took part in this study.

Author contributions

Data curation: Qingyong He.

Formal analysis: Qingyong He.

Funding acquisition: Qingyong He.

Investigation: Qingyong He.

Methodology: Feng Wang.

Project administration: Feng Wang.

Resources: Qingyong He.

Supervision: Feng Wang.

Validation: Qingyong He.

Visualization: Qingyong He.

Writing – original draft: Qingyong He.

Writing – review & editing: Feng Wang.