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 different periods of Tai Chi exercise on the kinesthesia of the lower limb joints of elderly women.

This study investigated the effects of different periods of Tai Chi exercise on knee and ankle joint kinesthesia. A total of 20 Tai Chi practitioners and 19 controls completed the final test. Customized devices were used to measure the kinesthesia of the knee and ankle joints at the start, after 24 weeks and after 48 weeks of the intervention. Results showed that the 24-week Tai Chi intervention considerably improved the kinesthesia of the knee flexion and extension and ankle dorsiflexion. The 48-week Tai Chi intervention improved the kinesthesia towards knee flexion and extension, ankle dorsiflexion and plantar flexion. Moreover, the 48-week Tai Chi intervention had better kinesthesia towards knee extension and ankle dorsiflexion compared with the 24-week Tai Chi intervention. Our results suggest that long-term (48 weeks versus 24 weeks) Tai Chi exercise benefits the knee and ankle kinesthesia of elderly women.

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 24-week Tai Chi exercise on the knee and ankle proprioception of older women.

This study examined the effects of regular Tai Chi (TC) exercise on the kinaesthesia of the knee and ankle joints of older women. A total of 43 women aged 55-68 years participated in this study. In a 24-week study period, the TC group (n = 22) underwent an organized TC exercise, whereas the control group (n = 21) maintained a sedentary lifestyle. Customized instruments were used to measure the threshold for the detection of the passive motion of the knee and ankle joints. After 24 weeks, the TC group showed a significantly smaller threshold for the detection of passive motion of knee extension (31.4%, p = 0.009), knee flexion (27.0%, p = 0.044), and ankle dorsal flexion (28.9%, p = 0.014) than the control group. Other comparisons showed no significant differences. The 24-week TC exercise benefited the lower-limb kinaesthesia of the knee joint flexion and extension and ankle dorsal flexion.

Effects of 24 weeks of Tai Chi Exercise on Postural Control among Elderly Women.

This study examined the effects of 24 weeks of Tai Chi Quan on the postural control of elderly women. A total of 43 women aged 55-68 years participated in the study. A Tai Chi group (n = 22) underwent an organized Tai Chi exercise, whereas the control group (n = 21) maintained a habitual, no-regular-exercise lifestyle. A Good Balance tester (Metitur, Finland) was used to measure the time, paths and velocity of the center of pressure (COP) of subjects during stance while shifting COP to targeted positions shown on a monitor. After 24 weeks, the Tai Chi group showed significantly shorter total (18.6%, p = 0.005), mediolateral (21.9%, p = 0.002) and anteroposterior (18.3%, p = 0.002) COP sway paths than the control group. The results indicate that 24 weeks of the Tai Chi exercise improved the efficiency of postural control for elderly women.

Foot forces induced through Tai Chi push-hand exercises.

The low impact forces of Tai Chi push-hand exercises may be particularly suited for older people and for those with arthritis; however, the biomechanics of push-hand exercises have not previously been reported. This paper examines the ground reaction forces (GRFs) and plantar force distributions during Tai Chi push-hand exercises in a stationary stance with and without an opponent. Ten male Tai Chi practitioners participated in the study. The GRFs of each foot were measured in three perpendicular directions using two force plates (Kistler). The plantar force distribution of each foot was measured concurrently using an insole sensor system (Novel). The results showed that the average maximum vertical GRF of each foot was not more than 88% ± 6.1% of the body weight and the sum of the vertical forces (103% ± 1.4%) generated by the two feet approximately equals the body weight at any one time. The horizontal GRFs generated by the two feet were in the opposite directions and the measured mean peak values were not more than 12% ± 2.8% and 17% ± 4.3% of the body weight in the medio-lateral and antero-posterior directions respectively. Among the nine plantar areas, the toes sustained the greatest plantar force. This study indicates that push-hand exercises generate lower vertical forces than those induced by walking, bouncing, jumping and Tai Chi gait, and that the greatest plantar force is located in the toe area, which may have an important application in balance training particularly for older adults.

Changes in muscle strength, endurance, and reaction of the lower extremities with Tai Chi intervention.

This study examines the effects of a 16-week Tai Chi (TC) training program on the muscle strength, endurance, and reaction time of the lower extremities of elderly people. A total of 40 elderly individuals (aged 60 years) completed the study. They were divided into two groups: the TC group (11 men and 11 women) underwent a supervised TC exercise program for 16 weeks, while the control group (9 men and 9 women) received general education for a comparable time period. Pre- and post-intervention measurements were conducted. An isokinetic dynamometer was used to measure the maximum concentric strength and dynamic endurance of the knee flexors and the extensors, and the maximum concentric strength of the ankle plantarflexors and dorsiflexors. The neuromuscular response of the rectus femoris, semitendinosus, gastrocnemius, and anterior tibialis muscles was measured by the onset latency to sudden perturbations using an electromyography system. After 16 weeks, the TC group showed a 19.9% increase in muscle strength of the knee flexors (p<.000) that was significantly greater than that in the control group (p=.046). There was also a significant decrease in semitendinosus muscle latency (6.6%, p=.014) that was significantly shorter than that in the control group (p=.042). No significant training effects were found in other measures. These results suggest that improving biomechanical characteristics of lower extremity muscles may need longer TC intervention for elderly people.

Temporal characteristics of foot movement in Tai Chi exercise.

The concept of proper foot movement is always emphasized in the practice of Tai Chi. Sixteen experienced Tai Chi practitioners participated in this study. Each subject practiced the whole set of 42-form Tai Chi movements and the performance was video-recorded and analyzed. The study found that Tai Chi is performed with the interchange of seven support patterns and six step directions of the foot. Compared with normal walking, there is a bigger percentage of time spent performing double support and less percentage of time spent performing single support movements in Tai Chi. However, the average duration of each support movement is longer and the change from one type of support to another is slower. In Tai Chi, the duration of steps in each direction is short and there are frequent changes from one direction to another. Tai Chi was found to be more effective than walking in simulating the gait challenges that are encountered in daily activities.

Tai Chi exercise and muscle strength and endurance in older people.

The purpose of the study was to investigate the influence of regular Tai Chi (TC) practice on muscle strength and endurance of the lower extremities in older people. Twenty-one long-term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30 degrees and 120 degrees /s. Ankle dorsiflexors and plantar flexors were tested at 30 degrees /s. Moreover the dynamic endurance of the knee flexors and extensors was assessed at the speed of 180 degrees /s. The strength of knee extensors and flexors in the sedentary group was significantly lower than that in the jogging group and marginally lower than that in the TC group at the higher velocity. For ankle joint, the subjects in both the TC group and the jogging group generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than the controls. Regular older TC practitioners and joggers showed better scores than the sedentary controls on most of the muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.

Tai Chi exercise and proprioception behavior in old people.

Eighty subjects aged over 60 participated in this study. Ankle and knee joint kinesthesia were measured in 21 long-term TC practitioners (TC group), 20 long-term swimming/running exercisers (S/R group), and 27 sedentary controls (control group). The results showed that ankle joint kinesthesia significantly differed among the three groups (p= 0.001). TC practitioners could detect a significantly smaller amount of motion than could the S/R exercisers (p = 0.022) and sedentary counterparts (p = 0.001). No significant difference was found between the S/R group and the sedentary control group (p = 0.701). For the knee joint, the threshold for detection of passive motion was significantly different in knee extension and flexion. For knee flexion, the TC group showed a significantly smaller mean threshold for detection of passive motion than did the subjects in the control group (p = 0.026). There were no significant differences between the S/R group and the control group (p = 0.312), the TC group and S/R group (p = 0.533). For knee extension, no significant difference was noted among the three groups (p = 0.597).

Biomechanics of Tai Chi: a review.

Tai Chi Chuan is a favourite form of exercise throughout the world and has drawn increasing research interest from international scientists. Biomechanical research into Tai Chi has grown substantially and has provided evidence of the beneficial effects of Tai Chi exercise on health, fitness, and prevention of falls. This paper reviews studies that have explored the biomechanical aspects of Tai Chi, such as balance, kinematics, kinetics, strength, and neuromuscular activities.

Plantar pressure distribution during Tai Chi exercise.

OBJECTIVES: To describe and quantify the plantar pressure distribution characteristics during Tai Chi exercise and to explain the beneficial effect of Tai Chi on balance control and muscle strength when compared with normal walking. DESIGN: Description and within-subject design. SETTING: A biomechanics laboratory. PARTICIPANTS: Sixteen experienced Tai Chi practitioners. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pressure-time integral, ground reaction force, and displacement of center of pressure (COP). RESULTS: During Tai Chi movements, the loading of the first metatarsal head and the great toe were significantly greater than in other regions (P<.05). The ground reaction forces varied between the Tai Chi movements and normal walking. Compared with normal walking, the locations of the COP in the Tai Chi movements were significantly more medial and posterior at initial contact (P<.05), and were significantly more medial and anterior at the end of contact with the ground (P<.05). The displacements of the COP were significantly wider (P<.05) in the mediolateral direction in the forward, backward, and sideways Tai Chi movements. The displacement was significantly larger (P<.05) in the anteroposterior direction in the forward movement. CONCLUSIONS: The plantar pressure characteristics of Tai Chi movements found in this study may be one of the important factors that Tai Chi exercise improves balance control and muscle strength.

Characteristics of foot movement in Tai Chi exercise.

BACKGROUND AND PURPOSE: The concept of proper foot movement is always emphasized in practicing Tai Chi (TC). The purposes of this study were to describe the foot movement characteristics of TC and to compare duration of single- and double-limb support time during TC and during walking. SUBJECTS: Sixteen experienced TC practitioners participated in the study. METHODS: The participants' performance of a whole set of 42-form TC movements was recorded with 2 cameras. A motion analysis system was used to identify the supporting and stepping characteristics of the foot during the practice. RESULTS: Seven foot support patterns and 6 step directions were identified. The results revealed that, compared with normal walking, TC movement had more double-limb support and less single-limb support in terms of total duration. The duration of each support pattern was longer, and movement from one pattern to the next was slow. The duration of each step direction was short, and changes of direction were frequent. DISCUSSION AND CONCLUSION: Support patterns changed slowly, and, combined with various step directions, they were found to be better than those of walking in simulating the gait challenges that may be encountered in daily activities.

Effect of regular Tai Chi and jogging exercise on neuromuscular reaction in older people.

OBJECTIVES: to investigate the effects of regular Tai Chi (TC) or jogging exercise on neuromuscular reaction in older people. DESIGN: cross-sectional study. SETTING: university biomechanics laboratory. SUBJECTS: 21 long-term elderly TC practitioners were compared with 18 regular elderly joggers and 22 sedentary counterparts. MEASUREMENTS: electromyography (EMG) was used to detect the neuromuscular reaction of the leg muscles to an unexpected ankle inversion perturbation. The latency of the muscles, which was defined as the time that the moment of perturbation began to the onset of the EMG response, was evaluated. RESULTS: a one-way ANOVA revealed that there were significant differences in the latency of the rectus femoris (R) and anterior tibialis (T) muscles between the three groups, but that there were no differences in the latency of the semitendinosus (S) and gastrocnemius (G) muscles. Further tests indicated that the R and T muscles in the TC and jogging groups were activated significantly faster than those in the control group. No significant difference was found for the muscle onset latencies between the TC and jogging groups. CONCLUSION: maintaining information processing speed during ageing is important, because of the role that it plays in many everyday events. The R and T muscles in the regular TC and jogging groups showed faster responses to unexpected ankle inversion perturbations, which is helpful for the timely correction of postural disturbances, than those in the sedentary control group.