Tai Chi counteracts age-related somatosensation and postural control declines among older adults.

Objective: To investigate the effect of a 16-week Tai Chi practice on strength, tactile sensation, kinesthesia, and static postural control among older adults of different age groups. Methods: This is a quasi-experimental study. Thirteen participants aged 60-69 years (60-69yr), 11 aged 70-79 years (70-79yr), and 13 aged 80-89 years (80-89yr) completed 16 weeks of 24-form Tai Chi practice. Their ankle and hip peak torque, tactile sensation, ankle and knee kinesthesia, and the root mean square of the center of pressure (Cop-RMS) were measured before (week 0) and after (week 17) practice. Results: 80-89yr showed less ankle plantar/dorsiflexion and hip abduction peak torques (p = 0.003, p < 0.001, p = 0.001), and a greater ankle plantar/dorsiflexion kinesthesia (p < 0.001, p = 0.002) than 60-69yr and 70-79yr. Greater ankle plantar/dorsiflexion and hip abduction torques (p = 0.011, p < 0.001, p = 0.045), improved arch and heel tactile sensation (p = 0.040, p = 0.009), and lower knee flexion/extension kinesthesia (p < 0.001, p = 0.044) were observed at week 17. The significant group*practice interaction for the fifth metatarsal head tactile sensation (p = 0.027), ankle plantar/dorsiflexion kinesthesia (p < 0.001, p = 0.004), and the CoP-RMS in the mediolateral direction (p = 0.047) only in 80-89yr revealed greater improvement at week 17. Conclusion: Tai Chi practice increased strength, tactile sensation, kinesthesia, and static postural control among older adults. Tai Chi practice improved tactile, kinesthesia sensations, and static postural control among older adults over 80, who presented with worse strength and kinesthesia than their younger counterparts. Tai Chi practice offers a safe exercise option for those aged over 80 to encourage improvements in sensorimotor control.

Muscle co-contraction and pre-activation in knee and ankle joint during a typical Tai Chi brush-knee twist-step.

This study aimed to investigate the co-contraction and pre-activation of agonistic and antagonistic muscles in experienced Tai Chi (TC) practitioners during normal walking (NW) and brush-knee twist-step (BKTS). The electromyographic activities of rectus femoris, biceps femoris, and tibialis anterior and lateral gastrocnemius muscles were collected during BKTS and NW in 28 TC practitioners. The pre-activation of knee and ankle joints before initial landing of left foot, and the co-contraction of knee and ankle joint in double-stance phase I (DSI), single-stance phase (SS), double-stance phase II (DSII), and swing phase (SW) were calculated during BKTS and NW. Ankle co-contraction significantly increased during DSI and SS in BKTS movements than compared with that in NW. For DSI and SW, SS and DSII, and DSII and SW, a significant difference was found in BKTS. The pre-activation of knee joint significantly decreased in BKTS and NW. This study indicated greater ankle joint muscle co-contraction in DSI and SS of stance phase and lower knee joint muscle co-contraction and pre-activation than in NW in BKTS movement. In addition, greater ankle joint muscle co-contraction was observed in the DSI, SS, and DSII of stance phase than those of swing phase in BKTS movement.

Tai Chi practice enables prefrontal cortex bilateral activation and gait performance prioritization during dual-task negotiating obstacle in older adults.

Background: With aging, the cognitive function of the prefrontal cortex (PFC) declined, postural control weakened, and fall risk increased. As a mind-body exercise, regular Tai Chi practice could improve postural control and effectively prevent falls; however, underlying brain mechanisms remained unclear, which were shed light on by analyzing the effect of Tai Chi on the PFC in older adults by means of functional near-infrared spectroscopy (fNIRS). Methods: 36 healthy older adults without Tai Chi experience were divided randomly into Tai Chi group and Control group. The experiment was conducted four times per week for 16 weeks; 27 participants remained and completed the experiment. Negotiating obstacle task (NOT) and negotiating obstacle with cognitive task (NOCT) were performed pre- and post-intervention, and Brodmann area 10 (BA10) was detected using fNIRS for hemodynamic response. A three-dimensional motion capture system measured walking speed. Results: After intervention in the Tai Chi group under NOCT, the HbO2 concentration change value (ΔHbO2) in BA10 was significantly greater (right BA10: p = 0.002, left BA10: p = 0.001), walking speed was significantly faster (p = 0.040), and dual-task cost was significantly lower than pre-intervention (p = 0.047). ΔHbO2 in BA10 under NOCT was negatively correlated with dual-task cost (right BA10: r = -0.443, p = 0.021, left BA10: r = -0.448, p = 0.019). There were strong negative correlations between ΔHbO2 and ΔHbR under NOCT either pre-intervention (left PFC r = -0.841, p < 0.001; right PFC r = -0.795, p < 0.001) or post-intervention (left PFC r = -0.842, p < 0.001; right PFC r = -0.744, p < 0.001). Conclusion: Tai Chi practice might increase the cognitive resources in older adults through the PFC bilateral activation to prioritize gait performance during negotiating obstacles under a dual-task condition.

Exploring the effects of peripheral sensibility on visuospatial and postural capacities during goal-directed movements in long-term Tai Chi practitioners.

Background: Falls are directly related to visuospatial ability and postural stability. Perturbations of upper body movements pose a challenge to older adults and may cause falls. This study investigated visuospatial ability and postural stability during goal-directed upper body movements between the Tai Chi and control groups and tried to connect them with their sensations. Materials and methods: Thirty-seven older adults were recruited to perform the touch (TT) and blind touch (BTT) tasks. The target positioning error (TPE), ankle proprioception, tactile sensation, time to stabilization (TTS), and maximum displacement (Dmax) of the center of pressure trajectory were compared between the groups during the tasks. The relationships of visuospatial ability and postural stability to proprioception and tactile sensation were investigated. Results: Dmax in the mediolateral (DmaxML) direction decreased during BTT compared to TT among the Tai Chi group but not the control group. Compared to the control group, less Dmax in the anterio-posterior (DmaxAP) direction, and shorter TTS in AP/ML (TTSAP/TTSML) directions were observed among the Tai Chi group. Compared to TT, DmaxAP decreased during the BTT. The Tai Chi group had less TPE in the vertical (TPEV) direction and in three-dimensional space. Among the Tai Chi group, TPEV, TTSML, and DmaxAP were correlated to their proprioception during plantarflexion; TTSAP was correlated to tactile sensation at the great toe during the TT and BTT; DmaxAP was correlated to tactile sensation at the great toe during the TT. Among the control group, TTSML was correlated to ankle proprioception during dorsiflexion and plantarflexion during the BTT. Conclusion: Long-term Tai Chi practitioners exhibited superior visuospatial ability and postural stability during goal-directed upper body movements, which was associated with sensitive proprioception and tactile sensation.

Effects of Tai Chi on the neuromuscular function of the patients with functional ankle instability: a study protocol for a randomized controlled trial.

BACKGROUND: Ankle instability limits physical activities and undermines a person's quality of life. Tai Chi's health benefits have been reported in different population groups. However, the effects of Tai Chi on neuromuscular function among young adults with functional ankle instability (FAI) remain unclear. Therefore, we aim to investigate the effect of Tai Chi on young adults with FAI. METHODS: This study will be conducted as a randomized controlled trial with blinded assessors. A total of 104 young adults with FAI will be recruited and randomly assigned to intervention and control groups. The participants in the simplified Tai Chi exercise program (STCEP) group will receive a 12-week Tai Chi training. The participants in the control group will receive a low-intensity exercise program and health education for 12 weeks. The primary and secondary outcomes will be assessed at baseline, 4th, 8th, and 12th weeks. Primary outcome measures will include the Cumberland Ankle Instability Tool (CAIT) score, kinematics/kinetics data, electromyography during single-leg landing tasks, and the modified Star Excursion Balance Test (mSEBT). Secondary outcome measures will include the total time of Dynamic Leap and Balance Test (DLBT), ankle muscle strength, and ankle proprioception. DISCUSSION: This study will investigate the effects of Tai Chi exercise on the neuromuscular function of patients with FAI, as indicated by ankle joint biomechanics, ankle proprioception, balance, ankle muscle strength, and ankle muscle activation. Results will demonstrate that Tai Chi can be an effective exercise for young adults with FAI. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100044089 . Registered on 10 March 2021.

Effects of Eight Methods and Five Steps of Tai Chi Practice on Balance Control Among Older Adults.

The team developed the newly compiled eight methods and five steps of Tai Chi (EMFSTC), which includes introductory routines to Tai Chi characterized by simple structures. This study examined the effectiveness of EMFSTC practice on balance control. A total of 31 participants were randomly assigned to EMFSTC (n = 15, age = 66.4 ± 1.7 years, received 16-week EMFSTC practice) or control (n = 16, age = 66.7 ± 1.8 years, received no practice) groups. Significant group by training interactions were observed. After EMFSTC practice, balance control improved, as indicated by decreased root mean square and mean velocity of center of pressure, proprioception threshold during knee extension, and plantar tactile sensitivity threshold at the arch. EMFSCT can be an effective rehabilitation modality to improve balance control among older adults.

Effects of a 16-week Tai Chi intervention on cutaneous sensitivity and proprioception among older adults with and without sensory loss.

This study investigated the effects of a 16-week Tai Chi (TC) intervention on cutaneous sensitivity and proprioception among older adults with and without sensory loss. Thirty-six older adults were divided into sensory loss and control groups, and they underwent a 16-week TC intervention. Significant interactions were detected in heel cutaneous sensitivity (p = 0.046, F = 4.419) and knee flexion (p = 0.043, F = 4.580), extension (p = 0.027, F = 5.529) and ankle plantar-flexion proprioception (p = 0.037, F = 4.860). The post hoc test indicated that in the sensory loss group, heel cutaneous sensitivity threshold (p = 0.034) and knee flexion (p = 0.004), extension (p = 0.002) and ankle plantar-flexion (p = 0.023) proprioception threshold decreased at week 17, whereas in the control group, knee flexion (p = 0.029) proprioception threshold decreased at week 17. TC intervention improved cutaneous sensitivity at more sites and proprioception in more joints among the older adults with sensory loss. TC intervention is a good option for older adults to exercise, and it is more effective among older adults with sensory loss.

Tai Chi practitioners have lower fall risks under dual-task conditions during stair descending.

Stairs are among the most hazardous locations, and stair descending contributes to a high risk of falls among the elderly under dual-task (DT) conditions. The purpose of this study was to determine whether the practitioners of Tai Chi (TC), one type of mind-body exercise, have lower fall risks under DT conditions during stair descending, compared with their no-exercise (NE) counterparts. Fifteen TC practitioners with at least 10 years of experience in TC and fifteen NE participants were recruited in this study. They were asked to descend a six-step staircase under single-task (ST) and DT conditions. An eight-camera motion analysis system and two force plates were used for data collection. Results showed group by DT interactions in walking velocity (p = 0.016) and center of mass-center of pressure inclination angle (COM-COP IA) in the anteroposterior directions (p = 0.026). Group effects observed with foot clearance (p = 0.031), trunk (p = 0.041) and head (p = 0.002) tilt angles, and COM-COP IA in the mediolateral (p = 0.006) directions. Significant DT effects only detected in foot clearance (p = 0.004). Although both groups of participants adopted a more cautious gait strategy under the dual-task condition, the TC practitioners were less influenced by the DT paradigm than their NE counterparts. Our observations indicated that TC practitioners have lower fall risks under DT conditions during stair descending.

The effect of Tai Chi practice on brain white matter structure: a diffusion tensor magnetic resonance imaging study.

Diffusion tensor imaging (DTI) measures the displacement of water molecules across tissue components and thus provides information on the microstructure of brain white matter. This study examined the effect of Tai Chi and the relation of Tai Chi experiences and skills with brain white matter. Fractional anisotropy (FA) was obtained from the DTI magnetic resonance images of two group participants, namely, the long-term Tai Chi practitioners and sedentary counterparts. Whole-brain voxel-based analysis showed that the Tai Chi group had higher FA in the splenium of corpus callosum (p = 0.015) than the control group. Rank correlation analysis revealed that in the Tai Chi group, the FA value of the splenium of corpus callosum was moderately related with exercise duration (r = 0.45, p = 0.045) but highly related with skill level (r = 0.699, p = 0.001). Long-term Tai Chi practice could benefit to the brain white matter, and these impacts were correlated with exercise duration and skill level.

Effects of Tai Chi Chuan and Brisk Walking Exercise on Balance Ability in Elderly Women: A Randomized Controlled Trial.

This study aims to investigate the effects of Tai Chi Chuan (TCC) and brisk walking (BW) on balance and training duration for the two exercises to significantly improve balance. A total of 48 elderly women were randomly divided into three groups. The TCC and BW groups completed a 60-min intervention training program with five sessions weekly for 16 weeks. Single-leg standing balance was tested every 4 weeks. Results showed that all the variables with eyes open improved on the eighth week (p < .05) in the TCC group and on the 12th week (p < .01) in the BW group. All variables with eyes closed improved on the 12th week (p < .01) in the TCC group and on the 16th week (p < .05) in the BW group. The results showed that 12 and 16 weeks of TCC and BW, respectively were essential to improve balance with eyes closed among the women aged 60-70 years.

Long-term Tai Chi practitioners have superior body stability under dual task condition during stair ascent.

BACKGROUND: Stair walking contributed to 26% of self-reported falls and become the leading cause of accidental death for the elderly. The risk of fall increases while performing a cognitive task, like talking and/or reasoning. RESEARCH QUESTION: Our work aimed to found out whether body stability under physical-cognitive dual task(DT) condition during stair ascent is superior among long-term Tai Chi (TC) practitioners. METHODS: Fifteen healthy, elderly long-term TC practitioners and fifteen no exercise(NE) practitioners were asked to walking ascent the stairs under single task(ST) and DT conditions in this cross-sectional study. Vicon motion analysis system and Kistler force plates were used synchronously to collect data. Ninety-five% confidence intervals, effect size and statistical power were calculated for each dependent variable to confirm significant difference. RESULTS: Compared with NE practitioners, TC practitioners had a lower head inclination angle, trunk inclination angle, hip angle, laterial impulse and center of mass-center of pressure(COM-COP)ap/ml separation, a higher ankle angle and loading rate under DT condition; TC practitioners had a lower head inclination angle, trunk inclination angle, higher ankle angle, loading rate and COM-COPml separation under ST condition. Compared with under ST condition, TC practitioners increased in minimum foot clearance, NE practitioners increased in laterial impulse and COM-COPml separation under DT condition. Under DT condition, body stability decreased among NE practitioners, while TC practitioners remained unchanged. SIGNIFICANCE: At present, there is no drug therapy proven to delay preclinical cognitive deterioration, it would be great helpful for the elderly if TC was been proved to improve their performance under cognitive related conditions.

Detraining effects of regular Tai Chi exercise on postural control ability in older women: A randomized controlled trial.

BACKGROUND/OBJECTIVE: This study aimed to investigate the training and detraining effects of Tai Chi (TC) on postural control ability in single leg stance (SLS) by conducting a single-blind randomized controlled trial. METHOD: Forty-eight older women were randomly divided into the TC, brisk walking (BW), and control(C) groups by using computer-generated program. The participants completed a 16-week intervention training and 8-week detraining program. Postural control ability in SLS was tested at the baseline, 16 t h, 20 t h, and 24 t h weeks. The primary outcomes included single-leg stance time (Time) and secondary outcomes included maximal displacement of the center of pressure (COP) in the anterior-posterior (AP) direction (D-ap), maximal displacement of the COP in the medial-lateral (ML) direction (D-ml), total length of the COP trajectories (Lng), and 95% confidence ellipse area of the COP movements (area), mean AP total excursion velocities (V-ap), and mean ML total excursion velocities (V-ml). RESULTS: Significant within-group difference compared with the baseline and between-groups difference compared with control group were found at 16 t h, 20 t h, and 24 t h weeks in the TC group and at the 16 t h and 20 t h weeks in the BW group in all the primary and secondary outcomes. Most of secondary outcomes including Lng, D-ml, V-ml, Area increased significantly at the 24 t h week compared with that at the 16 t h week in BW group. CONCLUSIONS: TC was effective in improving postural control ability and maintaining intervention gains, and was recommended as an appropriate exercise to prevent falls in the older adults.

Long-term Tai Chi exercise increases body stability of the elderly during stair ascent under high and low illumination.

The effects of long-term Tai Chi exercise on body stability of the elderly during stair ascent under high and low illumination were investigated. Forty-five healthy elderly women were divided into three groups, namely, Tai Chi exercise group, brisk walking group and no-exercise control group. All the participants ascended a staircase, during which force platforms and a motion capture system collected the data. Under the high illumination, Tai Chi exercise participants exhibited higher loading rate and anteroposterior centre of pressure (COPap) displacement as well as a lower braking impulse than no-exercise group. Under the low illumination, Tai Chi exercise participants demonstrated higher COPap and mediolateral centre of pressure (COPml) displacements as well as lower braking and lateral impulses compared with no-exercise participants. The centre of mass (COM)ml sway in Tai Chi and no exercise participants were higher, the loading rates in Tai Chi and walking participants were higher, and the lateral impulse in no exercise participants was higher under low illumination than under high illumination. Thus, low illumination increases the risk of falling. Tai Chi participants increased their foot clearance, head inclination angle and COPap displacement under low illumination to increase their stability during stair ascent.

Effects of Tai Chi Exercise on body stability among the elderly during stair descent under different levels of illumination.

The elderly are prone to stair descent falls under low illumination. Tai Chi, a traditional Chinese conditioning exercise, has been proved to improve body stability by altering body condition, gait, and proprioception. This study investigates whether Tai Chi exercise could improve body stability during stair descent under high and low illumination. Three groups of elderly women who practice Tai Chi, brisk walking, and no exercise were included. They descended from a simulated staircase. Tai Chi participants decreased horizontal velocity, centre of mass (COM) sway, and increased foot clearance compared with other participants, these movements could increase body stability; Compared with under high illumination, Tai Chi participants decreased horizontal velocity, loading rate, braking impulse, and increased inclination angle, COM sway, centre of pressure displacement under low illumination. Tai Chi participants were more sensitive to the difference in illumination, and took corresponding strategies to stabilize their bodies during stair descent.

Effect of 1-year regular Tai Chi on neuromuscular reaction in elderly women: a randomized controlled study.

This study assessed the effect of 1-year regular Tai Chi (TC) on neuromuscular reaction in elderly women. A total of 41 elderly women (55 years-68 years) completed the study. The TC group (n = 21) performed the 24-form TC, while the control group (C, n = 20) was instructed to read newspapers or watch television when the TC group practised. Electromyogram measurements were conducted before and after intervention. After a year-long intervention, the post-test results of between-group neuromuscular reaction time showed significant differences in the rectus femoris (t = 3.607, p = 0.001), semitendinosus (t = 2.678, p = 0.011), anterior tibialis (t = 3.455, p = 0.001), and gastrocnemius muscles (t = 4.061, p = 0.000). Within-group results showed that the TC group had significantly shorter neuromuscular reaction time compared to its baseline value in the rectus femoris (t = 3.066, p = 0.006), semitendinosus (t = 2.485, p = 0.022), anterior tibialis (t = 2.311, p = 0.032), and gastrocnemius muscles (t = 2.462, p = 0.023). Results suggested that year-long regular TC can improve neuromuscular reaction function in elderly women.

Effects of exercise on ankle proprioception in adult women during 16 weeks of training and eight weeks of detraining.

This study evaluates the effects of training and detraining on ankle proprioception in terms of kinesthesia in adult women. Sixty participants were randomly assigned to three groups. Tai Chi and Brisk Walking Groups went through a 16-week training period followed by an eight-week detraining period. The ankle plantar-flexion, dorsal-flexion, inversion, and eversion kinesthesia were measured every four weeks. The ankle kinesthesia in plantar/dorsal flexion of both exercise groups decreased, but the Tai Chi Group decreased more and sooner than the Brisk Walking Group. The training effects of Tai Chi exercise were retained but diminished during the detraining. The training effects of Brisk Walking exercise were not retained. The kinesthesia of ankle inversion and eversion remained unchanged after training. The results suggest that Tai Chi exercise is more effective in training ankle proprioception in plantar and dorsal flexion and in retaining the training effects compared with Brisk Walking exercise.

Strategies of stepping over obstacles: The effects of long-term exercise in older adults.

BACKGROUND: Stepping over obstacles challenges stability and is a leading cause of falls in older adult populations. As walking and Tai Chi (TC) exercise have been suggested practices for older adults for fall prevention, the purpose of this study was to evaluate the obstacle-crossing strategies of long-term TC practitioners and exercise walkers. METHODS: Thirty healthy older women (average age: 65.7 years) with either TC (n=15) experience (average experience: 8.2 years) or walking exercise (n=15; average experience: 8.8 years) participated in this study. We used three trial conditions: (1) normal walking, (2) crossing a 15cm (20% of leg length) obstacle, and (3) crossing a 23cm (30% of leg length) to assess obstacle-crossing strategy. Sagittal plane obstacle-crossing kinematic parameters and plantar pressures were used to evaluate the obstaclecrossing strategy. A MANOVA assessed differences between groups. RESULTS: Individuals with a TC background crossed the obstacle significantly faster with a significantly longer step relative to the exercise walkers. Plantar pressure profiles between the two groups also differed. Exercise walkers showed greater plantar pressure in the forefoot; TC practitioners demonstrated greater medial heel plantar pressure during obstacle-crossing. CONCLUSIONS: Our results suggest that obstacle-crossing strategies were affected by the type of longterm exercise. The strategies each group used had important attributes that affect stability during obstacle-crossing. Future studies are needed to understand how obstacle-crossing strategies are adopted and how exercise may influence the strategy used.