scholarly journals Best-Compromise Control Strategy Between Mechanical Energy Expenditure and Foot Clearance for Obstacle-Crossing in Older Adults: Effects of Tai-Chi Chuan Practice

2021 ◽  
Vol 9 ◽  
Author(s):  
Chien-Chung Kuo ◽  
Sheng-Chang Chen ◽  
Jr-Yi Wang ◽  
Tsung-Jung Ho ◽  
Tung-Wu Lu
Keyword(s):  
Energy Expenditure ◽  
Older People ◽  
Control Strategy ◽  
Tai Chi ◽  
Control Strategies ◽  
Mechanical Energy ◽  
Tai Chi Chuan ◽  
Obstacle Crossing ◽  
Foot Clearance

Background: Obstacle-crossing increases the risk of falls in older people. This study aimed to identify the effects of long-term Tai-Chi Chuan (TCC) practice on the control strategies for obstacle-crossing in older people.Methods: A multi-objective optimal control technique with measured gait data was used to identify the control strategies adopted by 15 long-term TCC practitioners and 15 healthy controls when crossing obstacles of different heights, in terms of the best-compromise weighting sets for the conflicting objectives of minimizing energy expenditure and maximizing the toe-obstacle and heel-obstacle clearances.Results and Conclusions: The long-term TCC older practitioners adopted a best-compromise control strategy similar to those adopted by young adults, with greater weightings on the minimization of the mechanical energy expenditure and smaller weightings on foot-clearance as compared to non-TCC controls (TCC: 0.72, 0.14, 0.14; Control: 0.55, 0.225, 0.225). This strategy enabled the long-term TCC older practitioners to cross obstacles with significantly greater leading-toe clearances but with relatively less mechanical energy expenditure. With the current approach, further simulations of obstacle-crossing mechanics with a given weighting set will be useful for answering clinically relevant what-if questions, such as what abilities would be needed if the non-TCC older people were to cross obstacles using the crossing strategy of the TCC people.

scholarly journals Effects of Tai-Chi Chuan Practice on Patterns and Stability of Lower Limb Inter-Joint Coordination During Obstructed Gait in the Elderly

2021 ◽  
Vol 9 ◽  
Author(s):  
Chien-Chung Kuo ◽  
Sheng-Chang Chen ◽  
Jr-Yi Wang ◽  
Tsung-Jung Ho ◽  
Jaung-Geng Lin ◽  
...  
Keyword(s):  
Lower Limb ◽  
Tai Chi ◽  
The Elderly ◽  
Tai Chi Chuan ◽  
Obstacle Crossing ◽  
Joint Coordination ◽  
Angular Velocities ◽  
Impact Exercise ◽  
Phase Angles

Losing balance or tripping during obstacle-crossing is one of the most frequent causes of falls in the elderly. As a low speed, low impact exercise, Tai Chi Chuan (TCC) can be promising in helping the elderly develop strategies for improved balance, inter-joint coordination, and end-point control during obstacle-crossing. This study investigates the effects of TCC training on the patterns and variability of the lower-limb inter-joint coordination during obstacle-crossing in the elderly. Fifteen older TCC practitioners and 15 healthy controls crossed obstacles of three different heights, while sagittal angles (x) and angular velocities (x′) of the hips, knees and ankles were measured and their phase angles obtained. The continuous relative phases (CRP) of the hip-knee and knee-ankle coordination were also calculated. The standard deviations of the CRP curve points were averaged to obtain deviation phase (DP) values for the stance and swing phases. The TCC group was found to cross obstacles with increased leading and trailing toe-clearances with unaltered CRP values when the swing toe was above the obstacle. Long-term TCC training altered the patterns and magnitudes of the CRPs primarily over double-limb support and significantly reduced the variabilities of leading knee-ankle and trailing hip-knee and knee-ankle CRP curves over the crossing cycle, regardless of obstacle height. The current results suggest that long-term TCC practice was helpful for a crossing strategy with significantly increased foot-obstacle clearances and reduced variability of the way the motions of the lower limb joints are coordinated during obstacle-crossing. These benefits may be explained by the long-lasting effects of continuous practice of the slow movement patterns emphasizing between-limb transfer of body weight in TCC.

scholarly journals Aging Affects Multi-Objective Optimal Control Strategies during Obstacle Crossing

2021 ◽  
Vol 11 (17) ◽  
pp. 8040
Author(s):  
Chien-Chung Kuo ◽  
Jr-Yi Wang ◽  
Sheng-Chang Chen ◽  
Tung-Wu Lu ◽  
Horng-Chaung Hsu
Keyword(s):  
Optimal Control ◽  
Energy Expenditure ◽  
Older People ◽  
Position Control ◽  
Control Strategies ◽  
The Body ◽  
Optimal Control Strategy ◽  
Obstacle Crossing ◽  
Multi Objective ◽  
Obstacle Clearance

Obstacle crossing challenges balance and increases the risk of falls in older people. Knowledge of the control strategies adopted by older people will be helpful for the study of the mechanisms of falls during obstacle crossing and the development of fall-prevention approaches. A mechanical model of the body combined with measured gait data was used to study the control strategies adopted by 17 healthy older and 17 young adults when crossing obstacles of different heights, in terms of the best-compromise weighting sets for the objectives of minimizing energy expenditure and maximizing the toe-obstacle and heel-obstacle clearances. The older group showed increased leading toe-obstacle clearance and trailing toe-obstacle distance, but decreased leading heel-obstacle distance. Compared with the young, the crossing strategy of older people emphasized the foot-obstacle clearance to reduce the risk of tripping, at the expense of energy expenditure. It appears that the multi-objective optimal control strategy relies on the muscular strength of the lower extremities and precise end-point control. Therefore, maintaining or improving the muscle strength and the ability of limb position control is critical for safe and successful obstacle-crossing in the older population.

The Effect of Tai Chi Chuan on Obstacle Crossing Strategy in Older Adults

2015 ◽  
Vol 23 (3) ◽  
pp. 315-329 ◽  
Author(s):  
Yao-Ting Chang ◽  
Chen-Fu Huang ◽  
Jia-Hao Chang
Keyword(s):  
Older Adults ◽  
Tai Chi ◽  
Tai Chi Chuan ◽  
Obstacle Crossing

scholarly journals Determining Whether Tai Chi Chuan is Related to the Updating Function in Older Adults: Differences Between Experts and Novices

2021 ◽  
Author(s):  
Yuan Yang ◽  
Tingting Chen ◽  
Xiaoxia Yuan ◽  
Xiaoke Zhong ◽  
Shoufu Yan ◽  
...  
Keyword(s):  
Older Adults ◽  
Tai Chi ◽  
The Elderly ◽  
Elderly Subjects ◽  
Cross Sectional ◽  
Tai Chi Chuan ◽  
Novice Group ◽  
Healthy Elderly ◽  
Back Task

Abstract Background: Tai Chi Chuan (TCC) is one effective method used to delay cognitive decline in older adults. However, the relationship between the long-term practice of TCC and the crucial working memory updating function of the brain in the elderly has not been comprehensively researched.Objective: This cross-sectional study explores how behavioral performance in a laboratory setting is related to long term practice of TCC on the updating function in older people using reaction times (RTs) of N-back tasks. Methods: 26 healthy elderly people participated in this experiment. According to the length of time TCC was practiced, 13 subjects in the TCC group had more than 5 years’ experience of TCC exercise, and 13 elderly subjects who had not been systematically exposed to mind-body exercise were assigned to the novice group. The N-back task was administered to every participant to evaluate the updating function. Results: The TCC group had faster RTs compared to the novice group (p<0.05); For the 1-back task, the TCC group showed faster RTs than the novice group. For the 2-back task, the novice group exhibited faster RTs than the TCC group. Conclusions: TCC experts exhibit greater updating function as compared to TCC novices. Long-term TCC appears to be positive associated with the updating function of older adults, making it an effective exercise to maintain cognitive function in the elderly.

scholarly journals Differential Effects of Tai Chi Chuan (Motor-Cognitive Training) and Walking on Brain Networks: A Resting-State fMRI Study in Chinese Women Aged 60

Healthcare ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 67 ◽  
Author(s):  
Chunlin Yue ◽  
Yanjie Zhang ◽  
Mei Jian ◽  
Fabian Herold ◽  
Qian Yu ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Physical Exercise ◽  
Older Women ◽  
Resting State ◽  
Tai Chi ◽  
Resting State Functional Connectivity ◽  
Tai Chi Chuan ◽  
Different Types ◽  
Walking Group

Background: This cross-sectional study aimed to investigate whether a long-term engagement in different types of physical exercise may influence resting-state brain networks differentially. In particular, we studied if there were differences in resting-state functional connectivity measures when comparing older women who are long-term practitioners of tai chi chuan or walking. Method: We recruited 20 older women who regularly practiced tai chi chuan (TCC group), and 22 older women who walked regularly (walking group). Both the TCC group and the walking group underwent a resting-state functional magnetic resonance imaging (rs-fMRI) scan. The acquired rs-fMRI data of all participants were analyzed using independent component analysis. Age and years of education were added as co-variables. Results: There were significant differences in default network, sensory-motor network, and visual network of rs-fMRI between the TCC group and walking group (p < 0.05). Conclusions: The findings of the current study suggested that long-term practice of different types of physical exercises (TCC vs. walking) influenced brain functional networks and brain functional plasticity of elderly women differentially. Our findings encourage further research to investigate whether those differences in resting-state functional connectivity as a function of the type of physical exercise have implications for the prevention of neurological diseases.

scholarly journals THREE-DIMENSIONAL KINEMATIC ANALYSIS OF STEPPING OVER OBSTACLES IN YOUNG SUBJECTS

2004 ◽  
Vol 16 (03) ◽  
pp. 157-164 ◽  
Author(s):  
HAO-LING CHEN ◽  
TUNG-WU LU ◽  
H. C. LIN
Keyword(s):  
Lower Limb ◽  
Control Strategies ◽  
Three Dimensional ◽  
Joint Kinematics ◽  
Obstacle Crossing ◽  
Obstacle Clearance ◽  
Foot Clearance ◽  
Young Subjects ◽  
And Control ◽  
Obstacle Height

A better understanding of the kinematics and control strategies adopted during obstacle crossing is essential for the prevention of injuries associated with falls in the elderly. The effects of obstacle height on the foot clearance, foot-obstacle distance and joint kinematics have presented significant controversy. This may be related to the selection of obstacle height, whether the obstacles are normalized to the leg length, and to the calculation of the foot-obstacle clearance, as well as the extraction of representative joint angles for the analysis. In this study, fourteen young healthy adults wearing 28 infrared retroreflective markers walked and crossed obstacles of heights of 0%, 10%, 20% and 30% of their leg lengths in a gait laboratory equipped with a 3D motion analysis system. Three-dimensional joint kinematics of the lower limb were calculated. Foot clearances were calculated using the heel and toe markers. The results suggested that young subjects maintained a constant margin of leading foot clearance when crossing higher obstacles (higher than 79.4mm) and a constant trailing foot clearance for all obstacle heights. Both toe-obstacle and heel-obstacle horizontal distances were not affected by obstacle height. Apart from the peak values, kinematic variables for the leading limb should be considered both when the toe and heel cross the obstacle while only those when the toe crosses the obstacle for the trailing limb. Not only in the sagittal plane, motions of the lower limb in the other two planes were also important when investigating the kinematics of the leading limb during obstacle crossing. The present study clarified some of the controversies in the literature of obstacle-crossing through careful comparisons of kinematic variables obtained from different study aspects. The results will be helpful for future studies to gain insight into the kinematics and control strategies adopted during obstacle-crossing.

scholarly journals Advanced automated emergency control strategy for embedded VSC-HVDC links

2020 ◽  
Vol 137 (8) ◽  
pp. 394-399
Author(s):  
Stefan Polster ◽  
Herwig Renner ◽  
Katrin Friedl ◽  
Olof Samuelsson
Keyword(s):  
Control Strategy ◽  
Voltage Stability ◽  
Control Strategies ◽  
Test System ◽  
Emergency Control ◽  
Simple Demonstration ◽  
Simulation Results ◽  
The Impact

AbstractThis paper proposes an advanced emergency control strategy for embedded VSC-HVDC links after AC disturbances, such as line tripping and generation loss. The control goals are to minimize the impact of the disturbance on the AC-network, which includes improving the long-term voltage stability with utilizing possible unloading capacity of parallel AC elements. The proposed algorithm is evaluated against other control strategies for embedded VSC-HVDC links by applying it to a simple demonstration network. The test system includes all necessary VSC converter dynamics, the VSC-HVDC link current and voltage limits and simple load recovery characteristics for an evaluation of the long term voltage stability. The simulation results are explained and the advantages of the proposed emergency control strategy are discussed.

INFLUENCE OF LONG-TERM TAI-CHI CHUAN TRAINING ON STANDING BALANCE IN THE ELDERLY

2012 ◽  
Vol 24 (01) ◽  
pp. 17-25 ◽  
Author(s):  
Tsung-Jung Ho ◽  
Sheng-Chang Chen ◽  
Shih-Wun Hong ◽  
Tung-Wu Lu ◽  
Jaung-Geng Lin
Keyword(s):  
Tai Chi ◽  
Center Of Pressure ◽  
Principal Component ◽  
The Elderly ◽  
Good Choice ◽  
Elderly Subjects ◽  
Tai Chi Chuan ◽  
Principal Axes ◽  
Challenging Tasks

Tai-Chi Chuan (TCC) is thought to be a low-impact and effective exercise to improve balance capability in the elderly. However, the effects of TCC exercise on balance improvement remain controversial. The purpose of the current study was to investigate the effects of long-term Yang-Style TCC training on balance variables such as stable standing time and center of pressure (COP) movement patterns. Fifteen long-term Yang-Style TCC practitioners and fifteen age-matched adults performed different static balance tests each for 30 seconds. For each test, the time-varying COP positions were measured by two forceplates. The sway area of the COP was described by an equivalent ellipse, the two principal axes of which were obtained by using principal component analysis. The results showed that elderly subjects with long-term Yang-Style TCC training were able to maintain stable standing longer than those without TCC training, with reduced COP sway area during challenging tasks such as single-leg stance and tandem stance. It is suggested that long-term TCC exercise is a good choice in a training program aimed at reducing the risk of falling in the elderly.

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