This study investigates the effects of a 12-week Tai Chi intervention on balance function in community-dwelling older adults. Participants are randomly assigned to either a Tai Chi exercise group or a health education control group. The primary outcome is balance function measured by the Berg Balance Scale. Secondary outcomes include physical function, psychological well-being, cognitive function, and sleep quality. The study also explores the predictive and modifying roles of baseline circadian age on intervention outcomes.
BACKGROUND AND RATIONALE Falls are a leading cause of injury and disability in older adults, and balance dysfunction is a key modifiable risk factor. Tai Chi, a traditional Chinese mind-body exercise, has been shown to improve balance, reduce fall risk, and benefit cognitive health in older populations. However, individual variability in response to Tai Chi remains poorly understood, and the biological mechanisms underlying its benefits are incompletely characterized. Circadian rhythm disruption has emerged as a hallmark of biological aging. The investigators have developed and validated a circadian age (CircAge) assessment system based on the UK Biobank cohort (N\>90,000), which independently predicts mortality risk. Whether individuals with accelerated circadian aging benefit more from Tai Chi intervention is unknown. This trial addresses this gap by integrating circadian age assessment with multi-modal outcome evaluations. OBJECTIVES The primary objective is to evaluate the effect of a 12-week Tai Chi intervention on balance function in community-dwelling older adults. Secondary objectives are to assess effects on physical function, psychological health, cognitive function, and sleep quality. Exploratory objectives are to examine the predictive and modifying roles of baseline circadian age acceleration on intervention outcomes. STUDY DESIGN This is a two-arm parallel, single-blind (assessor-blinded) randomized controlled trial. Ninety community-dwelling older adults are randomly allocated 1:1 to a Tai Chi group or a health education control group. Randomization is computer-generated using variable block sizes, stratified by sex and baseline Berg Balance Scale score (≤45 vs \>45). Allocation concealment is maintained via sequentially numbered opaque sealed envelopes. Outcome assessors are blinded to group allocation. After the 12-week intervention, the control group is offered free Tai Chi classes to ensure ethical equipoise. ASSESSMENT SCHEDULE Wrist-worn accelerometer (ActiGraph) recordings are collected at baseline over 7 consecutive days for circadian age computation. All baseline accelerometer recordings are completed prior to randomization. Full outcome assessments are conducted at baseline (week 0) and at the end of intervention (week 12). A streamlined midpoint assessment (week 6) includes only the Berg Balance Scale and Timed Up and Go test. Fasting blood samples for routine clinical chemistry are collected at week 0 and week 12. STATISTICAL ANALYSIS A sample size of 90 (45 per group) provides \>80% power to detect a standardized effect size of d=0.50 in Berg Balance Scale change at week 12, assuming α=0.05 (two-sided) and 20% attrition. The primary analysis follows the intention-to-treat principle using linear mixed-effects models adjusted for baseline score, age, sex, and circadian age acceleration, with class as a random effect for the Tai Chi group. Exploratory analyses include circadian age × group interaction terms. LONG-TERM FOLLOW-UP After the 12-week intervention, participants are invited to enter a long-term health database with periodic follow-ups tracking balance function, fall events, and overall health status.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
90
Yang-style 24-form Tai Chi taught by a nationally certified master coach. Classes are offered five days per week, with participants required to attend at least three sessions per week, for a total of 12 weeks (target: ≥36 sessions). Each 60-minute session includes a 10-minute warm-up, 35 minutes of Tai Chi practice, 10 minutes of cool-down (including standing meditation and breathing exercises), and 5 minutes for questions and home practice reminders. Class size is limited to 10-15 participants.
Structured health education program delivered by professional medical and health management staff. Seminars cover topics including nutrition and dietary guidance, chronic disease management (hypertension, diabetes), fall prevention strategies, safe medication use, and general health literacy for older adults. The intervention runs for 12 weeks. Participants receive the same health screening, evaluation, and feedback benefits as the Tai Chi group. Free Tai Chi classes are offered to this group after the intervention period ends.
Change in Berg Balance Scale (BBS) Score
The Berg Balance Scale (BBS) is a 14-item performance-based measure of static and dynamic balance. Each item is scored 0-4 based on the participant's ability to perform tasks such as sitting to standing, transfers, standing unsupported with eyes closed, turning, and single-leg stance. Total scores range from 0 to 56, with higher scores indicating better balance function. Lower scores are associated with increased fall risk.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Timed Up and Go (TUG) Test
Functional mobility and dynamic balance test. Participants stand from an armed chair, walk 3 meters, turn, walk back, and sit down. Time to complete the task is recorded in seconds. Longer times indicate poorer mobility and higher fall risk.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Grip Strength
Maximum grip strength measured using a handheld dynamometer, in kilograms. Three trials per hand; maximum value recorded. Higher values indicate greater muscle strength. Time Frame: Change from baseline to 12 weeks
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Balance Performance Measured by InBody Balance Trainer
Static balance assessed via center-of-pressure trajectory recorded by the InBody Balance Trainer during quiet standing, reported in millimeters. Shorter path length indicates better postural control.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Single-Leg Eye-Closed Standing Time
Static balance is assessed by measuring the time (in seconds) participants can maintain single-leg standing with eyes closed. Both legs are tested. Longer times indicate better static balance and proprioception.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Vertical Jump Height
Vertical jump test measures lower-extremity power and neuromuscular function. Participants perform three consecutive jumps, and the maximum jump height (in centimeters) is recorded.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Reaction Time
Reaction time test measures central nervous system processing speed using a portable reaction time device. Faster reaction times are associated with lower fall risk and better cognitive processing.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Activities-Specific Balance Confidence (ABC) Scale
The ABC Scale is a 16-item self-report measure of balance confidence during specific activities (e.g., walking, reaching, climbing stairs). Each item is rated 0-100%, with higher scores indicating greater balance confidence.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Geriatric Depression Scale (GDS-15) Score
The 15-item Geriatric Depression Scale (GDS-15) screens for depressive symptoms in older adults. Total scores range from 0 to 15, with scores ≥5 suggesting depression.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Generalized Anxiety Disorder Scale (GAD-7) Score
The 7-item Generalized Anxiety Disorder Scale (GAD-7) measures anxiety severity. Total scores range from 0 to 21, with scores ≥10 indicating moderate-to-severe anxiety.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Montreal Cognitive Assessment (MoCA) Score
The Montreal Cognitive Assessment (MoCA) is a 30-point cognitive screening tool covering visuospatial/executive function, naming, memory, attention, language, abstraction, delayed recall, and orientation. Scores ≥26 are considered normal cognitive function.
Time frame: Change from baseline to end of intervention, up to 12 weeks
Change in Pittsburgh Sleep Quality Index (PSQI) Score
The Pittsburgh Sleep Quality Index (PSQI) is a 19-item self-report questionnaire assessing sleep quality over the past month. Total scores range from 0 to 21, with scores \>5 indicating poor sleep quality.
Time frame: Change from baseline to end of intervention, up to 12 weeks
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