The influence of Tai Chi training on the center of pressure trajectory during gait initiation in older adults11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated

Determining the optimal leading limb for gait initiation in unilateral transtibial amputees: A systematic review

The selection of the leading limb during gait initiation in individuals with unilateral transtibial amputations can significantly affect various biomechanical parameters. However, there is currently no established recommendation for the suitable leading limb in this population. The systematic review was aimed to propose a preferred leading limb for gait initiation in individuals with unilateral transtibial amputations based on biomechanical parameters. Databases including Google Scholar, PubMed, Science Direct, and ISI Web of Knowledge, were searched. The first selection criterion was based on abstracts and titles to address the research question. A total of seven studies were included in this review, and the Downs and Black's checklist was used by three researchers to assess the risk of bias. The review included a total of 61 adults with unilateral transtibial amputations, with a mean age range of 41 to 64.43 years. The confidence level of the included studies was poor, and the observational cohort was the most common study design (n = 5). Most of the studies were not replicable. Four of the included studies recommended the prosthetic limb as the preferred leading limb. Individuals with unilateral transtibial amputations may experience biomechanical benefits, including a more normal center of pressure path, reduced limb loading, and increased ankle energy generation, when leading with their prosthetic limb during gait initiation. However, further research is necessary to establish a more conclusive recommendation for the preferred leading limb in this population.

Altered Anticipatory Postural Adjustments During Whole-Body Reaching in Subjects With Stroke

BACKGROUND

Coordination between arm movements and postural adjustments is crucial for reaching-while-stepping tasks involving both anticipatory postural adjustments (APAs) and compensatory movements to effectively propel the whole-body forward so that the hand can reach the target. Stroke impairs the ability to coordinate the action of multiple body segments but the underlying mechanisms are unclear. Objective. To determine the effects of stroke on reaching performance and APAs during whole-body reaching.

METHODS

We tested arm reaching in standing (stand-reach) and reaching-while-stepping (step-reach; 15 trials/condition) in individuals with chronic stroke (n = 18) and age-matched healthy subjects (n = 13). Whole-body kinematics and kinetic data were collected during the tasks. The primary outcome measure for step-reach was "gain" (g), defined as the extent to which the hip displacement contributing to hand motion was neutralized by appropriate changes in upper limb movements (g = 1 indicates complete compensation) and APAs measured as spatio-temporal profiles of the center-of-pressure shifts preceding stepping.

RESULTS

Individuals with stroke had lower gains and altered APAs compared to healthy controls. In addition, step onset was delayed, and the timing of endpoint, trunk, and foot movement offset was prolonged during step-reach compared to healthy controls. Those with milder sensorimotor impairment and better balance function had higher gains. Altered APAs were also related to reduced balance function.

CONCLUSIONS

Altered APAs and prolonged movement offset in stroke may lead to a greater reliance on compensatory arm movements. Altered APAs in individuals with stroke may be associated with a reduced shift of referent body configuration during the movement.

Propulsive forces and muscle activation during gait: comparisons between premenopausal and postmenopausal midlife women

OBJECTIVE

The aim of this study was to investigate whether there is a reduction in propulsive force during gait in postmenopausal women compared with premenopausal women.

METHODS

Forty-four women (21 premenopausal and 23 postmenopausal women) aged 40 to 55 years were selected. The ability to reach peak propulsive forces was assessed during the step execution test. The test was performed at the usual speed on 2 nonconsecutive days, with two attempts per day, using a force platform. Four temporal parameters were defined and calculated: initiation phase, preparation phase, swing phase, and total time. Peak force (anteroposterior and vertical) and time to reach peak force were obtained in both preparation and swing phases. The rate of force development was defined as peak force divided by time to reach peak force.

RESULTS

The postmenopausal women group presented a longer time in the preparation phase (540.6 ± 77 ms vs 482.5 ± 93 ms, P = 0.024) and consequently a longer total time in the step execution test (1,191 ± 106.4 ms vs 1,129 ± 114.3 ms, P = 0.045). There were differences between the groups for the rate of force development in the anteroposterior (postmenopausal women, 142.5 ± 38.1 N/s vs premenopausal women, 174.7 ± 70.5 N/s; P = 0.022) and vertical directions in the preparation phase (postmenopausal women, 102.7 ± 62.3 N/s vs premenopausal women, 145.3 ± 71 N/s; P = 0.012). No significant differences ( P > 0.05) were found in force, time to peak force, and rate of force development during the swing phase. In addition, there were no observed differences in surface electromyography of the medial and lateral gastrocnemius muscles during the preparation phase and swing phase of the step execution test between the two groups.

CONCLUSIONS

Postmenopausal women exhibited lower ability to generate propulsive force rapidly (rates of force development) in both the anteroposterior and vertical directions during the preparation phase of gait compared with premenopausal women. This indicates that postmenopausal women experience a reduction in propulsive force during gait.

Movement patterns during gait initiation in older adults with various stages of frailty: a biomechanical analysis

BACKGROUND

Gait initiation is challenging for older individuals with poor physical function, particularly for those with frailty. Frailty is a geriatric syndrome associated with increased risk of illness, falls, and functional decline. This study examines whether spatial and temporal parameters of gait initiation differ between groups of older adults with different levels of frailty, and whether fear of falling, and balance ability are correlated with the height of lifting the food during gait initiation.

METHODS

Sixty-one individuals aged > 65 years, classified by Fried frailty phenotype, performed five self-paced gait initiation trials. Data was collected using a three-dimensional passive optical motion capture system, consisting of 10 cameras with the ability to perceive reflective markers, and two force plates. The total duration of gait initiation and the duration of its four sub-phases, the first step length, and the maximum foot clearance during the first step were derived, and compared statistically between groups. Additionally, an association analysis was conducted between foot clearance and fear of falling, and confidence in balance in older individuals.

RESULTS

Frail individuals had significantly longer unloading durations, and total durations of gait initiation compared to non-frail older adults. Additionally, they had shorter first step lengths compared to non-frail older adults. Pre-frail older adults also showed shorter steps compared to the non-frail group. However, there were no significant differences between groups for the maximum foot clearance during the first step. Nevertheless, the maximum foot clearance of older individuals correlated significantly with their fear of falling and confidence in balance.

CONCLUSION

Older adults with reduced physical function and signs of frailty mainly display longer duration of gait initiation and decreased first step length compared to non-frail older adults. The release phase is decreased as the double support phase is prolonged in frail patients. This information can guide the development of specialized exercise programs to improve mobility in this challenging motion between static and dynamic balance.

Influences of cognitive load on center of pressure trajectory of young male adults with excess weight during gait initiation

Introduction: Falls and fall-related injuries in young male adults with excess weight are closely related to an increased cognitive load. Previous research mainly focuses on analyzing the postural control status of these populations performing cognitive tasks while stabilized walking progress but overlooked a specific period of walking known as gait initiation (GI). It is yet unknown the influences of cognitive load on this population's postural control status during GI. Objective: This study aimed to determine the influences of cognitive load on the center of pressure (CoP) trajectory of young male adults with excess weight during GI. Design: A controlled laboratory study. Methods: Thirty-six male undergraduate students were recruited and divided into normal-weight, overweight, and obese groups based on their body mass index (BMI). Participants' CoP parameters during GI under single and dual-task conditions were collected by two force platforms. A mixed ANOVA was utilized to detect significant differences. Results: Compared with the normal-weight group, the obese group showed significant changes in the duration and CoP parameters during sub-phases of GI, mainly reflecting prolonged duration, increased CoP path length, higher mediolateral CoP displacement amplitude, and decreased velocity of anteroposterior CoP displacement. During GI with 1-back task, significantly increased mediolateral CoP displacement amplitude occurred in the obese group. During GI with 2-back task, the obese group had increased CoP path length, higher mediolateral CoP displacement amplitude, as well as a decreased velocity of CoP displacement. Conclusion: Based on the changes in CoP parameters during GI with cognitive tasks, young male adults with excess weight, mainly obese ones, have compromised postural stability. During GI with a difficult cognitive task, obese young male adults are more susceptible to deterioration in their lateral postural balance. These findings indicate that the increased cognitive load could exacerbate obese young male adults' postural control difficulty during GI under dual-task conditions, putting them at a higher risk of experiencing incidents of falls. Based on these findings, we offer suggestions for therapists to intervene with these young male adults to ensure their safety of GI.

Dual-Task Interference Effects on Lower-Extremity Muscle Activities during Gait Initiation and Steady-State Gait among Healthy Young Individuals, Measured Using Wireless Electromyography Sensors

To maintain a healthy lifestyle, adults rely on their ability to walk while simultaneously managing multiple tasks that challenge their coordination. This study investigates the impact of cognitive dual tasks on lower-limb muscle activities in 21 healthy young adults during both gait initiation and steady-state gait. We utilized wireless electromyography sensors to measure muscle activities, along with a 3D motion capture system and force plates to detect the phases of gait initiation and steady-state gait. The participants were asked to walk at their self-selected pace, and we compared single-task and dual-task conditions. We analyzed mean muscle activation and coactivation in the biceps femoris, vastus lateralis, gastrocnemius, and tibialis anterior muscles. The findings revealed that, during gait initiation with the dual-task condition, there was a decrease in mean muscle activation and an increase in mean muscle coactivation between the swing and stance limbs compared with the single-task condition. In steady-state gait, there was also a decrease in mean muscle activation in the dual-task condition compared with the single-task condition. When participants performed dual-task activities during gait initiation, early indicators of reduced balance capability were observed. Additionally, during dual-task steady-state gait, the knee stabilizer muscles exhibited signs of altered activation, contributing to balance instability.

Effect of Laterally Moving Tactile Stimuli to Sole on Anticipatory Postural Adjustment of Gait Initiation in Healthy Males

This present study examined the effect of the laterally moving tactile stimuli (LMTS) to the sole on the anticipatory postural adjustment (APA) of the gait initiation. Thirteen healthy males participated in this study. A sound cue was provided at the beginning of each trial. The participants took three steps forward from a quiet stance at their preferred time after the start cue. The LMTS were delivered to the sole after the start cue. The loci of the tactile stimuli moved from the left- to the right-most side of the sole and then moved from the right- to the left-most side of that in a stimuli cycle. The duration of one stimuli cycle was 960 ms, and this cycle was repeated 16 times in a trial. The APA did not onset at the specific direction or phase of the LMTS, indicating that they did not use any specific phase of the stimuli as a trigger for initiating the gait. The LMTS decreased the amplitude and increased the duration of the APA. Simultaneously, the LMTS increased the time between the APA onset and toe-off of the initial support leg, indicating that they moved slowly when initiating gait during the LMTS. Those findings are explained by the view that the suppression of the APA induced via the LMTS to the sole is caused by the slowing down of the gait initiation due to masking the tactile sensation of the sole.

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

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.

An investigation to study the effects of Tai Chi on human gait dynamics using classical machine learning

Tai Chi has been proven effective in preventing falls in older adults, improving the joint function of knee osteoarthritis patients, and improving the balance of stroke survivors. However, the effect of Tai Chi on human gait dynamics is still less understood. Studies conducted in this domain only relied on statistical and clinical measurements on the time-series gait data. In recent years machine learning has proven its ability in recognizing complex patterns from time-series data. In this research work, we have evaluated the performance of several machine learning algorithms in classifying the walking gait of Tai Chi masters (people expert on Tai Chi) from the normal subjects. The study is designed in a longitudinal manner where the Tai Chi naive subjects received 6 months of Tai Chi training and the data was recorded during the initial and follow-up sessions. A total of 57 subjects participated in the experiment among which 27 were Tai Chi masters. We have introduced a gender, BMI-based scaling of the features to mitigate their effects from the gait parameters. A hybrid feature ranking technique has also been proposed for selecting the best features for classification. The research reports 88.17% accuracy and 93.10% ROC AUC values from subject-wise 5-fold cross-validation for the Tai Chi masters' vs normal subjects' walking gait classification for the "Single-task" walking scenarios. We have also got fairly good accuracy for the "Dual-task" walking scenarios (82.62% accuracy and 84.11% ROC AUC values). The results indicate that Tai Chi clearly has an effect on the walking gait dynamics. The findings and methodology of this study could provide preliminary guidance for applying machine learning-based approaches to similar gait kinematics analyses.

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

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.

Optimal exercise parameters of tai chi for balance performance in older adults: A meta-analysis

BACKGROUND

Tai chi is considered a safe and low-cost treatment for improving balance ability among an older population. However, there is no existing evidence on the optimal exercise parameters of tai chi for improving balance in older adults.

OBJECTIVES

To investigate the optimal parameters of a tai chi intervention to improve balance performance of older adults.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

PubMed, Embase, Cochrane Library, Web of Science, Scopus, China National Knowledge Infrastructure, Wanfang, Chinese Science and Technology Periodical and China Biology Medicine were searched from inception until November 30, 2020.

PARTICIPANTS

Adults aged 60 years and over.

MEASUREMENTS

Two reviewers independently extracted the data and assessed the quality of the included studies according to the Physiotherapy Evidence Database (PEDro) scale. Subgroup analyses and meta-regressions were conducted to elucidate the impact of tai chi training programs on balance measures.

RESULTS

Twenty-six eligible RCTs were included in the meta-analysis. Pooled results showed that tai chi has moderate effects for improving proactive balance (weighted mean standardized mean differences [SMD_wm ] = 0.61, 95% CI 0.33-0.89) and static steady-state balance (SMD_wm  = 0.62, 95% CI 0.30-0.95) and small effects for improving dynamic steady-state balance (SMD_wm  = 0.38, 95% CI 0.03-0.73) and balance test batteries (SMD_wm  = 0.47, 95% CI 0.13-0.81) in adults over 60 years of age. The practice frequency could predict the effects of tai chi on static steady-state balance, and the 24-form simplified Yang style tai chi (45-60 min/session, more than four sessions per week and at least 8 weeks) was the most optimal.

CONCLUSIONS

Tai chi is effective at improving the balance ability of adults over 60 years of age. A medium duration and high frequency of 24-form tai chi may be the optimal program for improving balance, but this evidence should be recommended with caution due to limitations of the methodology and small sample sizes.

A systematic review of center of pressure measures to quantify gait changes in older adults

Measures of gait center of pressure (COP) can be recorded using simple available technologies in clinical settings and thus can be used to characterize gait quality in older adults and its relationship to falls. The aim of this systematic review was to investigate the association between measures of gait COP and aging and falls. A comprehensive search of electronic databases including MEDLINE, Embase, Cochrane Central Register of Controlled Trials, CINAHL (EBSCO), Ageline (EBSCO) and Scopus was performed. The initial search yielded 2809 papers. After removing duplicates and applying study inclusion/exclusion criteria, 34 papers were included in the review. Gait COP has been examined during three tasks: normal walking, gait initiation, and obstacle negotiation. The majority of studies examined mean COP position and velocity as outcome measures. Overall, gait in older adults was characterized by more medial COP trajectory in normal walking and lower average anterior-posterior and medio-lateral COP displacements and velocity in both gait initiation and obstacle crossing. Moreover, findings suggest that Tai chi training can enhance older adults' balance control during gait initiation as demonstrated by greater COP backward, medial and forward shift in all three phases of gait initiation. These findings should be interpreted cautiously due to inadequacy of evidence as well as methodological limitations of the studies such as small sample size, limited numbers of 'fallers', lack of a control group, and lack of interpretation of COP outcomes with respect to fall risk. COP measures can be adopted to assess fall-related gait changes in older adults but more complex measures of COP that reveal the dynamic nature of COP behavior in step-to-step variations are needed to adequately characterize gait changes in older adults.

Multiple Inertial Measurement Unit Combination and Location for Center of Pressure Prediction in Gait

Center of pressure (COP) during a gait cycle indicates crucial information with regard to fall risk such as balance capacity. The drawbacks of conventional research instruments include inconvenient use during activities of daily living and expensive costs. The present study illustrates the promising fall-relevant information predicted by acceleration and angular velocity data from different placement sensors with machine learning techniques. This approach is inspired by the emerging machine learning technique, specifically the long short-term memory (LSTM), which is often used in time series data and aims to decrease the burden of the user while using the novel wearable technology. The Jaccard similarity coefficient, which implies the consistency of profile alignment between prediction and real situation, achieved 94% accuracy in the walking direction. Furthermore, the number of sensors used and the placement influenced the feasibility of an application. The outcome revealed that the accuracy could exceed 90% with only one sensor placed on the foot in the walking direction, and the toe would be the best location for sensor placement. To examine the performance of machine learning, the current study employed two parameters from different perspectives. One is a commonly used parameter, which represented the error, and the other investigated the similarity between the prediction and ground truth. From a similarity perspective, the parameter can be used as a metric to assess the consistency of profile alignment.

The effects of light touch cue on gait initiation in patients with Parkinson's disease

INTRODUCTION

One of the common impairments in patients with Parkinson's disease (PD) is disturbance of gait initiation. A light touch cue improves postural stability in patients with PD. Little is known about the effects of a light touch cue on gait initiation. This study investigated the effects of a light touch on gait initiation in patients with PD.

METHODS

This study was a cross-sectional study design. Sixteen patients with PD (Hoehn & Yahr stage 2-3) participated in the study and were evaluated two gait conditions (no touch (NT) and light touch (LT) conditions). Gait initiation was divided into 5 events including event A, B, C, D, and E. Outcome measures included maximum center of pressure (COP) displacement and velocity in anteroposterior (AP) and mediolateral (ML) directions, and the first step time.

RESULTS

Participants with LT had greater COP displacement compared with the NT condition in all events of gait initiation except COP-AP displacement in event D. Additionally, the COP velocity in LT condition was faster than the NT condition in COP-ML velocity in event A, COP-AP velocity in event B, COP-AP velocity and COP-ML velocity in event C. Moreover, participants with LT presented significantly shorter the first step time than the NT condition.

CONCLUSIONS

These findings demonstrated that a light touch cue improved gait initiation in patients with PD by increased weight shifting to initial stance limb, increased postural stability of stance limb, increased velocity of weight transfer toward stance limb, and a shortened first step time.

Effect of complementary therapies on functional capacity and quality of life among prefrail and frail older adults: A systematic review of randomized controlled trials

OBJECTIVE

Investigate the effects of complementary therapies on functional capacity and quality of life among prefrail and frail older adults.

MATERIALS AND METHOD

An electronic search was performed in the PubMed, EMBASE, Web of Science, Cochrane Library, LILACS and PEDro databases for relevant articles published up to September 2019. Only randomized controlled trials with interventions involving complementary therapies for prefrail and frail older adults were included. This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane recommendations. The methodological quality of the selected studies was appraised using the PEDro scale and the evidence was synthesized using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) scale.

RESULTS

Fifteen studies met the inclusion criteria and were selected for the present review. Six different complementary therapies were identified and the main findings were related to Tai Chi. A very low to moderate level of evidence was found regarding the effectiveness of Tai Chi in terms a functional capacity (balance, mobility, gait speed, functional reach and lower limb muscle strength) and a low level of evidence was found regarding its effect on quality of life. To the other complementary therapies it was not possible to synthetize evidence level.

CONCLUSION

Tai chi may be used as an important resource to improve functional capacity and quality of life among prefrail and frail older adults.

Magnitude, symmetry and attenuation of upper body accelerations during walking in women: The role of age, fall history and walking surface

OBJECTIVES

The present experiment examined the role of age and fall history in upper body accelerations when walking on an even and on an uneven surface.

STUDY DESIGN

An observational cross-sectional study.

MAIN OUTCOME MEASURES

The magnitude (root mean square [RMS]), symmetry (harmonic ratio) and attenuation (attenuation coefficient) of upper body accelerations were quantified as primary outcomes; gait spatiotemporal parameters were measured as secondary outcomes.

METHODS

Twenty young adults (mean ± SD age: 29.00 ± 4.51 yrs), 20 older non-fallers (66.60 ± 5.43 yrs) and 20 older fallers (68.55 ± 4.86 yrs) walked on an even and on an uneven surface, while wearing four accelerometers attached to the forehead, pelvis, right and left shanks.

RESULTS

Older fallers exhibited increased RMS acceleration in the mediolateral direction at the pelvis level compared with young adults when walking on the even surface (0.18 ± 0.04 vs. 0.14 ± 0.02, respectively), whereas walking on an uneven surface was associated with reduced magnitude of acceleration in older fallers (0.19 ± 0.04) compared with non-fallers (0.23 ± 0.04) and young adults (0.22 ± 0.03). Among other changes, walking on the uneven surface diminished pelvis-to-head attenuation in the mediolateral direction in older fallers (38.07 ± 14.51) compared with non-fallers (50.96 ± 11.03) and young adults (62.62 ± 8.21; all ps<0.05).

CONCLUSIONS

Reduced mediolateral accelerations in older fallers when walking on the uneven surface can be interpreted as a compensatory mechanism to preserve stability through increased body stiffness. Reduced postural flexibility in the frontal plane compromises the central role of the trunk in minimizing the impact of gait-related oscillations to the head, as evidenced by reduced mediolateral attenuation in older fallers.

The Left Posterior Parietal Cortex Contributes to the Selection Process for the Initial Swing Leg in Gait Initiation

The present study examined whether the left posterior parietal cortex contributes to the selection process for the initial swing leg in gait initiation. Healthy humans initiated the gait in response to an auditory start cue. Transcranial magnetic stimulation (TMS) was given over P3, P4, F3 or F4 simultaneously, with the auditory start cue, in the on-TMS condition. A coil was placed over one of the four TMS sites, but TMS was not given in the off-TMS condition. The probability of right leg selection in the on-TMS condition was significantly lower than in the off-TMS condition when the coil was placed over P3, indicating that the left posterior parietal cortex contributes to the selection process of the initial swing leg of gait initiation. The latency of the anticipatory postural adjustment for gait initiation with the left leg was shortened by TMS over F4 or P4, but with the right leg was shortened by TMS over P3 or P4. Thus, the cortical process affecting the time taken to execute the motor process of gait initiation with the right leg may be related to the selection process of the initial swing leg of gait initiation.

Augmented reality-assisted training with selected Tai-Chi movements improves balance control and increases lower limb muscle strength in older adults: A prospective randomized trial

Background

Tai-Chi benefits older adults by enhancing balance control and increasing the muscle strength of the lower limbs. However, a complete set of traditional Tai-Chi exercises is sometimes too difficult for beginners. We investigated whether practicing augmented reality-assisted training with selected Tai-Chi movements tailored to the practitioner’s ability (selected Tai-Chi, or sTC) is as effective as performing a complete set of Tai-Chi sequences (complete traditional Tai-Chi, or tTC).

Methods

In this prospective randomized trial carried out in the Beitou District of Taipei City, Taiwan, community-dwelling adults aged ≥65 and without any debilitating diseases (n = 28) were included. Participants were randomly assigned to the sTC group (n = 14) or the tTC group (n = 14). Participants in the sTC group practiced selected Tai-Chi movements using the augmented reality Tai-Chi training system. Participants of the tTC group were asked to complete the 24-form Yang-style Tai-Chi following the instructions of Tai-Chi masters. Each training session lasted 30 min, with 3 sessions per week for 8 weeks. Pre- and post-intervention evaluations included functional balance tests, comprising the Berg Balance Scale (BBS), Timed Up and Go test (TUG), and Functional Reach Test (FRT), as well as muscle strength measurements of the lower extremities.

Results

Pre-intervention evaluations showed significant differences in FRT (p = 0.034) and left hip abductor muscle strength (p = 0.046) between the sTC and tTC groups. After 8 weeks of training, the BBS, TUG, and FRT scores in the sTC group showed significant improvement overall. Although all three functional balance test scores improved in the tTC group, only the improvement in BBS was statistically significant (p = 0.001). After 8 weeks, all muscle strength measurements increased by an average of 3.1 ± 1.0 kgw in the sTC group and 1.6 ± 0.8 kgw in the tTC group.

Conclusions

The augmented reality-assisted training with selected Tai-Chi movements, designed based on objective measurements of the practitioner’s capability, improved balance control and muscle strength of lower limbs at least as effectively as the complete sequence of traditional Tai-Chi exercises.

Trial registration

This study was approved by the Institutional Review Board of National Yang-Ming University (IRB number: 1000087). Written informed consent was obtained from all participants.

Tai Chi is an effective form of exercise to reduce markers of frailty in older age

Frailty affects the quality of life of older age adults by limiting mobility, reducing physiological reserve and reducing independence. The frailty phenotype is typically characterised by exhaustion, loss or lack of physical activity, weight loss and weakness, although more recently there have been proposals to extend the frailty criteria to include physiological characteristics such as inflammation, oxidative stress and vascular function. Exercise has the potential to prevent, delay or even reverse frailty, but not all exercise is perceived as suitable for an older age population. The purpose of this study was to test Tai Chi and Zumba Gold® as exercise interventions in older age adults (65 to 75 years old) to improve characteristics related to the frailty phenotype. Muscle strength and flexibility (functional fitness as a measure of weakness), cardiorespiratory fitness, blood pressure, vascular function (FMD), markers of oxidative stress (total antioxidant capacity, malondialdehyde, 8-isoprostane, protein carbonyl), inflammation (CRP) and aspects of wellbeing related to exhaustion were assessed at baseline (pre-), 6 weeks (mid-) and 12 weeks (post-intervention). Both Tai Chi and Zumba Gold® improved systolic blood pressure, vascular function, and functional fitness following the 12 week intervention to a similar extent. Furthermore Antioxidant capacity was significantly increased (303 ± 15.56 vs. 336 ± 18.82 μm; p = 0.0028) and lipid oxidation significantly reduced (36.41 ± 6.4 vs 13.49 ± 2.5 pg/ml; p = 0.0042) after 12 weeks of Tai Chi compared to baseline. Anxiety, physical and mental fatigue decreased in both groups, with a greater decrease in mental fatigue in the Tai Chi group. Taken together, these changes suggest that Tai Chi has the potential to reduce outcomes related to the extended frailty phenotype in older age adults.

Characteristics of the gait initiation phase in older adults with diabetic peripheral neuropathy compared to control older adults

BACKGROUND

Gait is deteriorated in older adults with diabetic peripheral neuropathy; however, too little is known about the gait initiation phase. We aimed to determine if gait initiation variables are more sensitive in identifying the extent to which diabetic peripheral neuropathy impacts gait.

METHODS

We examined steps, distance, speed and dynamic balance in the gait initiation phase using a validated algorithm based on wearable sensors in 38 older adults with diabetic peripheral neuropathy and 33 non-diabetic, non-neurologic, non-orthopedic control older adults (≥65 years) under single-task and dual-task gait conditions.

FINDINGS

During the single-task gait condition, the largest differences between the two groups were found in gait initiation steps and dynamic balance (66.7% more steps and 57.2% poorer balance for the diabetic group; effect size = 1.08 and 1.11, respectively; all p < 0.05), while gait speed had a medium effect (10.9% slower for the diabetic group; effect size = 0.54; p < 0.05). Although gait deteriorated for both groups during the dual-task gait condition compared to the single-task gait condition, effect sizes of the between-group differences remained similar. The differences in gait initiation steps and dynamic balance between the two groups were independent of gait speed.

INTERPRETATION

Gait initiation steps and dynamic balance may be more sensitive than gait speed for detecting gait deterioration due to diabetic peripheral neuropathy. Given the association between gait initiation and risk for fall, our findings suggest that gait initiation variables may be important outcomes for clinical management of diabetic peripheral neuropathy.

What happens before the first step? A New Approach to Quantifying Gait Initiation Using a Wearable Sensor

BACKGROUND

Walking is a volitional behavior that requires planning and initiation before a step is observed. Following a signal to begin walking, studies of gait initiation in specialized labs have identified three phases that occur during the transition from a standing position via anticipatory postural adjustment (APA) to the first step. Routine instrumented gait testing outside of the laboratory setting focuses on gait execution and does not include gait initiation measures.

RESEARCH QUESTION

Can a single IMU sensor be used for performing gait initiation evaluations outside the lab?

METHODS

We recorded walking in young (N = 41) and older (N = 26) adults using an instrumented gait mat while they were wearing a 3D accelerometer on their lower back. Subjects were instructed to begin walking following an auditory signal. An algorithm was developed to extract the following measures from the acceleration signal: gait initiation time, measured from the start of the auditory cue to begin walking and ends at the heel-strike of the swing leg, time-to-APA (reaction time), APA duration and swing time (execution of the first step).

RESULTS

Intraclass correlation coefficient analysis showed good to excellent agreement between gait initiation metrics obtained with the gait mat and the wearable sensor (mean 0.88, range [0.75-0.96]). Except for swing time, all measures were longer in the older subjects, compared to the young adults (p < 0.01).

SIGNIFICANCE

Extracting gait initiation measures from routine instrumented gait testing may facilitate studies that can better determine the extent to which impaired gait planning and execution contribute to mobility impairments.

Postural control processes during standing and step initiation in autism spectrum disorder

Background

Individuals with autism spectrum disorder (ASD) show a reduced ability to maintain postural stability, though motor control mechanisms contributing to these issues and the extent to which they are associated with other gross motor activities (e.g., stepping) are not yet known.

Methods

Seventeen individuals with ASD and 20 typically developing (TD) controls (ages 6–19 years) completed three tests of postural control during standing. During the neutral stance, individuals stood with their feet shoulder width apart. During the Romberg one stance, they stood with feet close together. During the circular sway, participants stood with feet shoulder width apart and swayed in a circular motion. The standard deviation (SD) of their center of pressure (COP) in the mediolateral (ML) and anteroposterior (AP) directions and the COP trajectory length were examined for each stance. We also assessed mutual information (MI), or the shared dependencies between COP in the ML and AP directions. Participants also completed a stepping task in which they stepped forward from one force platform to an adjacent platform. The amplitude and duration of anticipatory postural adjustments (APAs) were examined, as were the maximum lateral sway, duration, and velocity of COP adjustments following the initial step. We examined stepping variables using separate one-way ANCOVAs with height as a covariate. The relationships between postural control and stepping measures and ASD symptom severity were assessed using Spearman correlations with scores on the Autism Diagnostic Observation Schedule–Second Edition (ADOS-2) and the Autism Diagnostic Interview-Revised (ADI-R).

Results

Individuals with ASD showed increased COP trajectory length across stance conditions (p = 0.05) and reduced MI during circular sway relative to TD controls (p = 0.02). During stepping, groups did not differ on APA amplitude (p = 0.97) or duration (p = 0.41), but during their initial step, individuals with ASD showed reduced ML sway (p = 0.06), reduced body transfer duration (p < 0.01), and increased body transfer velocity (p = 0.02) compared to controls. Greater neutral stance COP_ML variability (r = 0.55, p = 0.02) and decreased lateral sway (r = − 0.55, p = 0.02) when stepping were associated with more severe restricted and repetitive behaviors in participants with ASD.

Conclusions

We found that individuals with ASD showed reduced MI during circular sway suggesting a reduced ability to effectively coordinate joint movements during dynamic postural adjustments. Additionally, individuals with ASD showed reduced lateral sway when stepping indicating that motor rigidity may interfere with balance and gait. Postural control and stepping deficits were related to repetitive behaviors in individuals with ASD indicating that motor rigidity and key clinical issues in ASD may represent overlapping pathological processes.

Characteristics of medial-lateral postural control while exposed to the external perturbation in step initiation

Controllability of posture in the medial-lateral direction is critical for balance maintenance, particularly in step initiation. The objective of the current study was to examine  the effects of external perturbation and landing orientation on medial-lateral control stability in step initiation. Eleven young healthy participants stood on the force platform and waited for the instruction of taking a step while experiencing a pendulum perturbation applied at the lateral side of the right shoulder. Eight experimental conditions were conducted by two levels of step side (right or left), two levels of perturbation (with or without), and two levels of landing orientation (forward or diagonal). The center of pressure (COP), pelvic movements, and muscle activities were recorded and analyzed as the onset of COP and pelvic movement, the COP displacement, and cocontraction and reciprocal muscle activation pattern. The temporal events of COP and pelvic movement were not significantly different in all experimental conditions. However, COP and pelvic movement were significantly later in the diagonal condition. Most of the segments showed reciprocal muscle activation patterns in relation to the perturbation released time. Subsequently, all segments showed cocontraction muscle activation patterns, which was significantly affected by step side, perturbation, and orientation. The results suggest that how the CNS initiated a step was identical with the COP then pelvic movement. The outcome highlights the importance of external perturbation and foot landing orientation effects on postural adjustments, which may provide a different approach to help step initiation.

Effects of Taekkyon training on balance control during stair descent in community-dwelling older adults

[Purpose] The purpose of this study was to examine the effects of Taekkyon training on balance control during stair descent in community-dwelling older adults. [Participants and Methods] Participants were randomly assigned to either the Taekkyon group or wellness education group. The participants in the Taekkyon group received Taekkyon training 2 times a week for 12 weeks. The participants in the wellness education group participated in a health education program 1 hour weekly for 12 weeks. Subjects stood in a predetermined position on the top of the custom-built 3-step staircase and then descended the stairs at a self-paced speed. The changes in the translation of the center of pressure before and after Taekkyon training were measured. [Results] The Taekkyon group showed a greater increase in the displacement of the center of pressure in the anteroposterior and mediolateral directions as well as the average velocity of the center of pressure in posttesting than the wellness education group. The Taekkyon group also showed a significant increase in all measures after Taekkyon training. However, little change was found in all measures in the wellness education group. [Conclusion] These findings support the use of Taekkyon training as an effective fall-preventive rehabilitation program to reduce falling in older adults.

Postural stability during gait for adults with hereditary spastic paraparesis

Individuals with hereditary spastic paraparesis (HSP) are often impaired in their ability to control posture as a result of the neurological and musculoskeletal implications of their condition. This research aimed to assess postural stability during gait in a group of adults with HSP. Ten individuals with HSP and 10 healthy controls underwent computerized gait analysis while walking barefoot along a 10-m track. Two biomechanics methods were used to assess stability: the center of pressure and center of mass separation (COP-COM) method, and the extrapolated center of mass (XCOM) method. Spatiotemporal and kinematic variables were also investigated. The XCOM method identified deficits in mediolateral stability for the HSP group at both heel strike and mid-stance. The group with HSP also had slower walking velocity, lower cadence, more time spent in double stance, larger step widths, and greater lateral trunk flexion than the control group. These results suggest that individuals with HSP adjust characteristics of their gait to minimize the instability arising from their impairments but have residual deficits in mediolateral stability. This may result in an increased risk of falls, particularly in the sideways direction.

Gait initiation and partial body weight unloading for functional improvement in post-stroke individuals

BACKGROUND

To better understand gait initiation in individuals with stroke and suggest possible training strategies, we compared the gait initiation of individuals with stroke and age-matched controls, and we examined the influence of different amounts of body weight support (BWS) during the execution of gait initiation in individuals with stroke.

MATERIALS AND METHODS

Twelve individuals with stroke and 12 age-matched controls initiated gait after a verbal command at a self-selected and comfortable speed, and individuals with stroke also initiated gait wearing a harness with 0%, 15%, and 30% of BWS. Length and velocity of the first step, distance between heels, and weight bearing in both lower limbs in the initial position were calculated. We also assessed the displacement and average velocity of the center of pressure (CoP) in the medial-lateral (ML) and anterior-posterior (AP) directions in 3 distinct sections during gait initiation, which correspond to the CoP position toward the swing limb, stance limb and progression line, respectively.

RESULTS

Individuals with stroke presented shorter and slower step, shorter and slower CoP-ML and CoP-AP toward swing limb and Cop-ML towards stance limb, and longer and faster CoP-AP toward stance limb compared to their peers. The BWS lead individuals with stroke to decrease step length and to increase CoP-ML displacement and average velocity toward stance limb.

CONCLUSION

Individuals with stroke present impairments in executing gait initiation mainly during the preparation period and the employment of an overground BWS system promotes a better performance. These results suggest that BWS is a functional strategy that enables individuals with stroke to modulate gait initiation and it could be adopted for gait intervention.

Anticipatory postural adjustments and spatial organization of motor cortex: evidence of adaptive compensations in healthy older adults

During anticipated postural perturbations induced by limb movement, the central nervous system generates anticipatory postural adjustments (APAs) in the trunk and hip musculature to minimize disturbances to equilibrium. Age-related changes in functional organization of the nervous system may contribute to changes in APAs in healthy older adults. Here we examined if altered APAs of trunk/hip musculature in older adults are accompanied by changes in the representation of these muscles in motor cortex. Twelve healthy older adults, 5 with a history of falls and 7 nonfallers, were compared with 13 young adults. APAs were assessed during a mediolateral arm raise task in standing. Temporal organization of postural adjustments was quantified as latency of APAs in the contralateral external oblique, lumbar paraspinals, and gluteus medius relative to activation of the deltoid. Spatial organization was quantified as extent of synergistic coactivation between muscles. Volume and location of the muscle representations in motor cortex were mapped using transcranial magnetic stimulation. We found that older adults demonstrated significantly delayed APAs in the gluteus medius muscle. Spatial organization of the three muscles in motor cortex differed between groups, with the older adults demonstrating more lateral external oblique representation than the other two muscles. Separate comparisons of the faller and nonfaller subgroups with young adults indicated that nonfallers had the greatest delay in gluteus medius APAs and a reduced distance between the representational areas of the lumbar paraspinals and gluteus medius. This study indicates that altered spatial organization of motor cortex accompanies altered temporal organization of APA synergies in older adults.

NEW & NOTEWORTHY Anticipatory postural adjustments are a critical component of postural control. Here we demonstrate that, in healthy older adults with and without a history of falls, delayed anticipatory postural adjustments in the hip musculature during mediolateral perturbations are accompanied by altered organization of trunk/hip muscle representation in motor cortex. The largest adaptations are evident in older adults with no history of falls.

Contribution of the supplementary motor area and the cerebellum to the anticipatory postural adjustments and execution phases of human gait initiation

Several brain structures including the brainstem, the cerebellum and the frontal cortico-basal ganglia network, with the primary and premotor areas have been shown to participate in the functional organization of gait initiation and postural control in humans, but their respective roles remain poorly understood. The aim of this study was to better understand the role of the supplementary motor area (SMA) and posterior cerebellum in the gait initiation process. Gait initiation parameters were recorded in 22 controls both before and after continuous theta burst transcranial stimulation (cTBS) of the SMA and cerebellum, and were compared to sham stimulation, using a randomized double-blind design study. The two phases of gait initiation process were analyzed: anticipatory postural adjustments (APAs) and execution, with recordings of soleus and tibialis anterior muscles. Functional inhibition of the SMA led to a shortened APA phase duration with advanced and increased muscle activity; during execution, it also advanced muscle co-activation and decreased the duration of stance soleus activity. Cerebellar functional inhibition did not influence the APA phase duration and amplitude but increased muscle co-activation, it decreased execution duration and showed a trend to increase velocity, with increased swing soleus muscle duration and activity. The results suggest that the SMA contributes to both the timing and amplitude of the APAs with no influence on step execution and the posterior cerebellum in the coupling between the APAs and execution phases and leg muscle activity pattern during gait initiation.

Electromyographic Pattern during Gait Initiation Differentiates Yoga Practitioners among Physically Active Older Subjects

During gait initiation, postural adjustments are needed to deal with balance and movement. With aging, gait initiation changes and reflects functional degradation of frailty individuals. However, physical activities have demonstrated beneficial effects of daily motor tasks. The aim of our study was to compare center of pressure (COP) displacement and ankle muscle co-activation during gait initiation in two physically active groups: a group of walkers (n = 12; mean age ± SD 72.6 ± 3.2 years) and a yoga group (n = 11; 71.5 ± 3.8 years). COP trajectory and electromyography of leg muscles were recorded simultaneously during five successive trials of gait initiation. Our main finding was that yoga practitioners had slower COP displacements (p < 0.01) and lower leg muscles % of coactivation (p < 0.01) in comparison with walkers. These parameters which characterized gait initiation control were correlated (r = 0.76; p < 0.01). Our results emphasize that lengthy ankle muscle co-activation and COP path in gait initiation differentiate yoga practitioners among physically active subjects.

The impact of Tai Chi and Qigong mind-body exercises on motor and non-motor function and quality of life in Parkinson's disease: A systematic review and meta-analysis

PURPOSE

To systematically evaluate and quantify the effects of Tai Chi/Qigong (TCQ) on motor (UPDRS III, balance, falls, Timed-Up-and-Go, and 6-Minute Walk) and non-motor (depression and cognition) function, and quality of life (QOL) in patients with Parkinson's disease (PD).

METHODS

A systematic search in 7 electronic databases targeted clinical studies evaluating TCQ for individuals with PD published through August 2016. Meta-analysis was used to estimate effect sizes (Hedges's g) and publication bias for randomized controlled trials (RCTs). Methodological bias in RCTs was assessed by two raters.

RESULTS

Our search identified 21 studies, 15 of which were RCTs with a total of 735 subjects. For RCTs, comparison groups included no treatment (n = 7, 47%) and active interventions (n = 8, 53%). Duration of TCQ ranged from 2 to 6 months. Methodological bias was low in 6 studies, moderate in 7, and high in 2. Fixed-effect models showed that TCQ was associated with significant improvement on most motor outcomes (UPDRS III [ES = -0.444, p < 0.001], balance [ES = 0.544, p < 0.001], Timed-Up-and-Go [ES = -0.341, p = 0.005], 6 MW [ES = -0.293, p = 0.06], falls [ES = -0.403, p = 0.004], as well as depression [ES = -0.457, p = 0.008] and QOL [ES = -0.393, p < 0.001], but not cognition [ES = -0.225, p = 0.477]). I² indicated limited heterogeneity. Funnel plots suggested some degree of publication bias.

CONCLUSION

Evidence to date supports a potential benefit of TCQ for improving motor function, depression and QOL for individuals with PD, and validates the need for additional large-scale trials.

Center of pressure and center of mass behavior during gait initiation on inclined surfaces: A statistical parametric mapping analysis

This study analyzed gait initiation (GI) on inclined surfaces with 68 young adult subjects of both sexes. Ground reaction forces and moments were collected using two AMTI force platforms, of which one was in a horizontal position and the other was inclined by 8% in relation to the horizontal plane. Departing from a standing position, each participant executed three trials in the following conditions: horizontal position (HOR), inclined position at ankle dorsi-flexion (UP), and inclined position at ankle plantar-flexion (DOWN). Statistical parametric mapping analysis was performed over the entire center of pressure (COP) and center of mass (COM) time series. COP excursion did not show significant differences in the medial-lateral (ML) direction in both inclined conditions, but it was greater in the anterior-posterior (AP) direction for both inclined conditions. COP velocities are smaller in discrete portions of GI for the UP and DOWN conditions. COM displacement was greater in the ML direction during anticipatory postural adjustments (APA) in the UP condition, and COM moves faster in the ML direction during APA in the UP condition but slower at the end of GI for both the UP and the DOWN conditions. The COP-COM vector showed a greater angle in the DOWN condition. We observed changes for COP and COM in GI in both the UP and the DOWN conditions, with the latter showing changes for a great extent of the task. Both the UP and the DOWN conditions showed increased COM displacement and velocity. The predominant characteristic during GI on inclined surfaces, including APA, appears to be the displacement of the COM.

Atypical anticipatory postural adjustments during gait initiation among individuals with sub-acute stroke

Anticipatory postural adjustments, executed prior to gait initiation, help preserve lateral stability when stepping. Atypical patterns of anticipatory activity prior to gait initiation may occur in individuals with unilateral impairment (e.g., stroke). This study aimed to determine the prevalence, correlates, and consequences of atypical anticipatory postural adjustment patterns prior to gait initiation in a sub-acute stroke population. Forty independently-ambulatory individuals with sub-acute stroke stood on two force plates and initiated gait at a self-selected speed. Medio-lateral centre of pressure displacement was calculated and used to define anticipatory postural adjustments (shift in medio-lateral centre of pressure >10mm from baseline). Stroke severity, motor recovery, and functional balance and mobility status were also obtained. Three patterns were identified: single (typical), absent (atypical), and multiple (atypical) anticipatory postural adjustments. Thirty-five percent of trials had atypical anticipatory postural adjustments (absent and multiple). Frequency of absent anticipatory postural adjustments was negatively correlated with walking speed. Multiple anticipatory postural adjustments were more prevalent when leading with the non-paretic than the paretic limb. Trials with multiple anticipatory postural adjustments had longer duration of anticipatory postural adjustment and time to foot-off, and shorter unloading time than trials with single anticipatory postural adjustments. A high prevalence of atypical anticipatory control prior to gait initiation was found in individuals with stroke. Temporal differences were identified with multiple anticipatory postural adjustments, indicating altered gait initiation. These findings provide insight into postural control during gait initiation in individuals with sub-acute stroke, and may inform interventions to improve ambulation in this population.

The relative and absolute reliability of center of pressure trajectory during gait initiation in older adults

It has been thought that for scientific acceptance of a parameter, its psychometric properties such as reliability, validity and responsiveness have critical roles. Therefore, this study was conducted to estimate how many trials are required to obtain a reliable center of pressure (COP) parameter during gait initiation (GI) and to investigate the effect of number of trials on the relative and absolute reliability. Twenty older adults participated in the study. Subjects began stepping over the force platform in response to an auditory stimulus. Ten trials were collected in one session. The displacement, velocity, mean and median frequency of the COP in the mediolateral (ML) and anteroposterior (AP) directions were evaluated. Relative reliability was determined using the intraclass correlation coefficient (ICC), and absolute reliability was evaluated using the standard error of measurement (SEM) and minimal detectable change (MDC₉₅). The results revealed with respect to parameter, one to five trials should be averaged to ensure excellent reliability. Moreover, ICC, SEM% and MDC₉₅% values were between 0.39-0.89, 4.84-41.5% and 13.4-115% for single trial and 0.86-0.99, 1.74-19.7% and 4.83-54.7% for ten trials averaged, respectively. Moreover, the ML and AP COP displacement in locomotor phase had the most relative reliability as well as the ML and AP median frequency in locomotor phase had the most absolute reliability. In general, the results showed that the COP-related parameters in time and frequency domains, based on average of five trials, provide reliable outcome measures for evaluation of dynamic postural control in older adults.

Evidence of a conservative gait strategy in athletes with a history of concussions

BACKGROUND

A history of 3 or more concussions is frequently associated with numerous short- and long-term neuropathologies. Impairments in postural control are a known acute consequence of concussion; however, limited evidence exists on the effects of multiple concussions on gait. The purpose of this study was to assess gait stepping characteristics in collegiate aged student-athletes based on concussion history.

METHODS

There were 63 participants divided into 3 even groups based on concussion history: ≥3 concussions, 1-2 concussions, and 0 concussion. All participants completed 10 trials of gait on a 4.9 m instrumented walkway. The dependent variables of interest included both gait stepping characteristics (step velocity, length, and width, double support time, and the percentage of the gait cycle in stance) and coefficient of variability (CoV) measures (step length, time, and width). The gait stepping characteristics were compared first with a MANOVA with follow-up 1-way ANOVAs and Tukey post hoc tests as appropriate. The CoV measures were compared with 1-way ANOVAs and Tukey post hoc tests.

RESULTS

There were main effects for group for step velocity, length, width, and double support time. Overall, the 0 concussion group displayed typical healthy young gait parameters and performed significantly better than either concussion group. The 0 concussion group had a significantly greater step length CoV, but there were no differences in the step time or width CoV.

CONCLUSION

This finding provides evidence of subtle impairments in postural control during gait among individuals with prior history of concussion which could be an early indicator of future neurological deficiencies. The limited difference in the variability measures is consistent with prior static stance studies and could suggest the individuals constrain their motor systems to reduce variability. Taken together, these findings suggest a conservative gait strategy which is adopted by individuals with a history of concussions.

Mind-Body Exercises for Nurses with Chronic Low Back Pain: An Evidence-Based Review

Background. Chronic low back pain (CLBP) among nurses is a growing health concern. The multimodal nature of mind-body exercises has potential to impact physiological and psychological processes associated with chronic pain, affording possible advantages over conventional unimodal therapies. This paper summarizes the prevalence of and risk factors for CLBP among nurses, reviews the effectiveness in treating pain and disability of mind-body exercises (yoga and tai chi) for CLBP among the general and nursing population, and describes implications. Methods. Articles, published during or prior to 2015, were systematically identified through the PubMed/MEDLINE, Web of Science, and ScienceDirect databases using the following search terms: nurses, mind-body, integrative, biopsychosocial, yoga, tai chi, back pain, and/or risk factors. Results. Prevalence estimates of CLBP among nurses ranged from 50% to 80%. Associated risk factors for CLBP included lifestyle and physical, psychological, psychosocial, and occupational factors. No published studies were identified that evaluated yoga or tai chi for nurses with CLBP. Studies in the general population suggested that these interventions are effective in reducing pain and disability and may improve factors/processes predictive of CLBP. Conclusion. This review suggests that evaluating the impact of multimodal interventions such as yoga and tai chi for nurses with CLBP warrants investigation.

Balance Improvement Effects of Biofeedback Systems with State-of-the-Art Wearable Sensors: A Systematic Review

Falls and fall-induced injuries are major global public health problems. Balance and gait disorders have been the second leading cause of falls. Inertial motion sensors and force sensors have been widely used to monitor both static and dynamic balance performance. Based on the detected performance, instant visual, auditory, electrotactile and vibrotactile biofeedback could be provided to augment the somatosensory input and enhance balance control. This review aims to synthesize the research examining the effect of biofeedback systems, with wearable inertial motion sensors and force sensors, on balance performance. Randomized and non-randomized clinical trials were included in this review. All studies were evaluated based on the methodological quality. Sample characteristics, device design and study characteristics were summarized. Most previous studies suggested that biofeedback devices were effective in enhancing static and dynamic balance in healthy young and older adults, and patients with balance and gait disorders. Attention should be paid to the choice of appropriate types of sensors and biofeedback for different intended purposes. Maximizing the computing capacity of the micro-processer, while minimizing the size of the electronic components, appears to be the future direction of optimizing the devices. Wearable balance-improving devices have their potential of serving as balance aids in daily life, which can be used indoors and outdoors.

Characteristic muscle activity patterns during gait initiation in the healthy younger and older adults

It is thought that gait initiation (GI) might be an optimal task for identifying postural control deficiencies. Thus, the aim of this study was to clarify the strategies adopted by older subjects during this task. 16 healthy younger and 15 healthy older adults participated in the study. Subjects were instructed to begin forward stepping with their dominant limb in response to an auditory stimulus. The mean muscle activity, co-contraction index, and intra-subject coefficients of variation (intra-subject CVs) of dominant limb muscles in different phases of GI were measured. The level of association between the co-contraction index and intra-subject CV of muscles was also explored. This study showed that in the anticipatory phase, the younger group had larger amplitudes and more intra-subject CVs than older the group, particularly for the tibialis anterior muscle. However, the co-contraction index was greater in older subjects relative to younger subjects. During the weight transition phase, tibialis anterior, semitendinosus and vastus lateralis muscles of older adults had a lower amplitude as compared to younger adults. However, during the locomotor phase, the activity of tibialis anterior was greater in comparison to younger adults. Also, during this phase, similar to the anticipatory phase, the co-contraction index between tibialis anterior and gastrocnemius muscles was greater in older subjects relative to younger subjects. Additionally, the larger co-contraction index of some muscles was associated with smaller intra-subject CV. These findings suggest that muscle behaviors are altered with aging and older adults employ different strategies in the different phases of GI as compared to younger adults.

Footwear and Foam Surface Alter Gait Initiation of Typical Subjects

Gait initiation is the task commonly used to investigate the anticipatory postural adjustments necessary to begin a new gait cycle from the standing position. In this study, we analyzed whether and how foot-floor interface characteristics influence the gait initiation process. For this purpose, 25 undergraduate students were evaluated while performing a gait initiation task in three experimental conditions: barefoot on a hard surface (barefoot condition), barefoot on a soft surface (foam condition), and shod on a hard surface (shod condition). Two force plates were used to acquire ground reaction forces and moments for each foot separately. A statistical parametric mapping (SPM) analysis was performed in COP time series. We compared the anterior-posterior (AP) and medial-lateral (ML) resultant center of pressure (COP) paths and average velocities, the force peaks under the right and left foot, and the COP integral x force impulse for three different phases: the anticipatory postural adjustment (APA) phase (Phase 1), the swing-foot unloading phase (Phase 2), and the support-foot unloading phase (Phase 3). In Phase 1, significantly smaller ML COP paths and velocities were found for the shod condition compared to the barefoot and foam conditions. Significantly smaller ML COP paths were also found in Phase 2 for the shod condition compared to the barefoot and foam conditions. In Phase 3, increased AP COP velocities were found for the shod condition compared to the barefoot and foam conditions. SPM analysis revealed significant differences for vector COP time series in the shod condition compared to the barefoot and foam conditions. The foam condition limited the impulse-generating capacity of COP shift and produced smaller ML force peaks, resulting in limitations to body-weight transfer from the swing to the support foot. The results suggest that footwear and a soft surface affect COP and impose certain features of gait initiation, especially in the ML direction of Phase 1.

Tai Chi Training may Reduce Dual Task Gait Variability, a Potential Mediator of Fall Risk, in Healthy Older Adults: Cross-Sectional and Randomized Trial Studies

Background

Tai Chi (TC) exercise improves balance and reduces falls in older, health-impaired adults. TC’s impact on dual task (DT) gait parameters predictive of falls, especially in healthy active older adults, however, is unknown.

Purpose

To compare differences in usual and DT gait between long-term TC-expert practitioners and age-/gender-matched TC-naïve adults, and to determine the effects of short-term TC training on gait in healthy, non-sedentary older adults.

Methods

A cross-sectional study compared gait in healthy TC-naïve and TC-expert (24.5 ± 12 years experience) older adults. TC-naïve adults then completed a 6-month, two-arm, wait-list randomized clinical trial of TC training. Gait speed and stride time variability (Coefficient of Variation %) were assessed during 90 s trials of undisturbed and cognitive DT (serial subtractions) conditions.

Results

During DT, gait speed decreased (p < 0.003) and stride time variability increased (p < 0.004) in all groups. Cross-sectional comparisons indicated that stride time variability was lower in the TC-expert vs. TC-naïve group, significantly so during DT (2.11 vs. 2.55%; p = 0.027); by contrast, gait speed during both undisturbed and DT conditions did not differ between groups. Longitudinal analyses of TC-naïve adults randomized to 6 months of TC training or usual care identified improvement in DT gait speed in both groups. A small improvement in DT stride time variability (effect size = 0.2) was estimated with TC training, but no significant differences between groups were observed. Potentially important improvements after TC training could not be excluded in this small study.

Conclusion

In healthy active older adults, positive effects of short- and long-term TC were observed only under cognitively challenging DT conditions and only for stride time variability. DT stride time variability offers a potentially sensitive metric for monitoring TC’s impact on fall risk with healthy older adults.

Discriminating features of gait performance in progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) is the most common form of atypical Parkinsonism; however it is underdiagnosed and often misdiagnosed as Parkinson's disease (PD).

METHODS

We investigated gait initiation (GI) and gait performance in a total of 36 participants (12 PSP, 12 PD and 12 healthy age- and gender-matched controls) to gain further insight into specific motor deficits that characterize dynamic postural control and gait in PSP. Anticipatory postural adjustments (APAs), quantified by center of pressure (COP) displacement and speed prior to an initial heel off, and the maximum distance (COPCOM) between COP and center of mass (COM) during all three GI phases were calculated to evaluate dynamic postural control. Steady-state gait performance was also evaluated and compared across the groups.

RESULTS

APAs in PSP were significantly altered such that the posterior COP shift is profoundly diminished when compared to PD (p < 0.05). Moreover, proper velocity control during GI in PSP was affected, particularly in the mediolateral direction, when compared to PD (p < 0.05). The diminished COPCOM distance is further indicative of more severe dynamic postural instability in PSP than in PD (p < 0.05). Significant differences in spatiotemporal parameters, inter-step variability, and asymmetry during gait in PSP, in comparison with PD were also identified (all p's < 0.05).

CONCLUSION

The present study reveals that the compensatory GI strategy in PSP is distinct from PD and paradoxically induces lateral instability. Further, gait performance in PSP is slower and more variable which could be the consequence of lateral instability and fear of falling.

The influence of accuracy constraints on EMG and kinetic variables during gait initiation

[Purpose] This study investigated the effects of accuracy constraints (targets) placed on the stepping-limb heel-strike (HS) on the electromyogram (EMG) and ground reaction forces (GRFs) during gait initiation. [Subjects and Methods] Twenty healthy subjects (29.2 ± 2.9 years) were asked to begin walking or stepping over a 10-cm-high obstacle at a fast speed. A 3-cm-diameter target was placed on the ground to dictate the position and accuracy of the stepping-limb HS. [Results] The results showed that the initiation velocity increase in the no-target conditions was due to modulation of the stance- and stepping-limb GRFs and a corresponding increase in the tibialis anterior (TA) activities of both limbs before stepping-limb toe-off. This was achieved by significantly increasing the stepping- and stance-limb TAEMG1 (determined between the onset of movement and time to peak anteroposterior (A-P) GRF of the stepping- and stance- limb) for the no-target conditions. It seems, therefore, that TAEMG1 and the slope to stepping-limb peak A-P GRF contributed to the intended velocity of initiation. [Conclusion] These data indicate that gait initiation and/or stepping over an obstacle may prove to be tasks by which motor control can be measured. The present study provides insight into the working mechanisms of the stepping and stance limbs and shows a clear need to further investigate whether the intact or affected limb should be used to initiate gait during rehabilitation and prosthetic training.

Monaural Auditory Cue Affects the Process of Choosing the Initial Swing Leg in Gait Initiation

The authors investigated the effect of an auditory cue on the choice of the initial swing leg in gait initiation. Healthy humans initiated a gait in response to a monaural or binaural auditory cue. When the auditory cue was given in the ear ipsilateral to the preferred leg side, the participants consistently initiated their gait with the preferred leg. In the session in which the side of the monaural auditory cue was altered trial by trial randomly, the probability of initiating the gait with the nonpreferred leg increased when the auditory cue was given in the ear contralateral to the preferred leg side. The probability of choosing the nonpreferred leg did not increase significantly when the auditory cue was given in the ear contralateral to the preferred leg side in the session in which the auditory cue was constantly given in the ear contralateral to the preferred leg side. The reaction time of anticipatory postural adjustment was shortened, but the probability of choosing the nonpreferred leg was not significantly increased when the gait was initiated in response to a binaural auditory cue. An auditory cue in the ear contralateral to the preferred leg side weakens the preference for choosing the preferred leg as the initial swing leg in gait initiation when the side of the auditory cue is unpredictable.

Effectiveness of traditional Chinese medicine as an adjunct therapy for Parkinson's disease: a systematic review and meta-analysis

Background

Idiopathic Parkinson disease (PD) is a common neurodegenerative disease that seriously hinders limb activities and affects patients’ lives. We performed a meta-analysis aiming to systematically review and quantitatively synthesize the efficacy and safety of traditional Chinese medicine (TCM) as an adjunct therapy for clinical PD patients.

Methods

An electronic search was conducted in PubMed, Cochrane Controlled Trials Register, China National Knowledge Infrastructure, Chinese Scientific Journals Database and Wanfang data to identify randomized trials evaluating TCM adjuvant therapy versus conventional treatment. The change from baseline of the Unified Parkinson’s Disease Rating Scale score (UPDRS) was used to estimate the effectiveness of the therapies.

Results

Twenty-seven articles involving 2314 patients from 1999 to 2013 were included. Potentially marked improvements were shown in UPDRS I (SMD 0.68, 95%CI 0.38, 0.98), II (WMD 2.41, 95%CI 1.66, 2.62), III (WMD 2.45, 95%CI 2.03, 2.86), IV (WMD 0.32, 95%CI 0.15, 049) and I-IV total scores (WMD 6.18, 95%CI 5.06, 7.31) in patients with TCM plus dopamine replacement therapy (DRT) compared to DRT alone. Acupuncture add-on therapy was markedly beneficial for improving the UPDRS I–IV total score of PD patients (WMD 10.96, 95%CI 5.85, 16.07). However, TCM monotherapy did not improve the score. The effectiveness seemed to be more obvious in PD patients with longer adjunct durations. TCM adjuvant therapy was generally safe and well tolerated.

Conclusions

Although the data were limited by methodological flaws in many studies, the evidence indicates the potential superiority of TCM as an alternative therapeutic for PD treatment and justifies further high-quality studies.

Analysis of static and dynamic balance in healthy elderly practitioners of Tai Chi Chuan versus ballroom dancing

OBJECTIVE

To determine whether Tai Chi Chuan or ballroom dancing promotes better performance with respect to postural balance, gait, and postural transfer among elderly people.

METHODS

We evaluated 76 elderly individuals who were divided into two groups: the Tai Chi Chuan Group and the Dance Group. The subjects were tested using the NeuroCom Balance Master¯ force platform system with the following protocols: static balance tests (the Modified Clinical Tests of Sensory Interaction on Balance and Unilateral Stance) and dynamic balance tests (the Walk Across Test and Sit-to-stand Transfer Test).

RESULTS

In the Modified Clinical Test of Sensory Interaction on Balance, the Tai Chi Chuan Group presented a lower sway velocity on a firm surface with open and closed eyes, as well as on a foam surface with closed eyes. In the Modified Clinical Test of Sensory Interaction on Unilateral Stance, the Tai Chi Chuan Group presented a lower sway velocity with open eyes, whereas the Dance Group presented a lower sway velocity with closed eyes. In the Walk Across Test, the Tai Chi Chuan Group presented faster walking speeds than those of the Dance Group. In the Sit-to-stand Transfer Test, the Tai Chi Chuan Group presented shorter transfer times from the sitting to the standing position, with less sway in the final standing position.

CONCLUSION

The elderly individuals who practiced Tai Chi Chuan had better bilateral balance with eyes open on both types of surfaces compared with the Dance Group. The Dance Group had better unilateral postural balance with eyes closed. The Tai Chi Chuan Group had faster walking speeds, shorter transfer times, and better postural balance in the final standing position during the Sit-to-stand Test.

Lighten Up: Specific Postural Instructions Affect Axial Rigidity and Step Initiation in Patients With Parkinson's Disease

BACKGROUND

Parkinson's disease (PD) is associated with stooped postural alignment, increased postural sway, and reduced mobility. The Alexander Technique (AT) is a mindfulness-based approach to improving posture and mobility by reducing muscular interference while maintaining upward intentions. Evidence suggests that AT can reduce disability associated with PD, but a mechanism for this effect has not yet been established.

OBJECTIVE

We investigated whether AT-based instructions reduce axial rigidity and increase upright postural alignment, and whether these instructions have different effects on postural alignment, axial rigidity, postural sway, and mobility than effort-based instructions regarding posture.

METHOD

Twenty subjects with PD practiced 2 sets of instructions and then attempted to implement both approaches (as well as a relaxed control condition) during quiet standing and step initiation. The "Lighten Up" instructions relied on AT principles of reducing excess tension while encouraging length. The "Pull Up" instructions relied on popular concepts of effortful posture correction. We measured kinematics, resistance to axial rotation, and ground reaction forces.

RESULTS

Both sets of experimental instructions led to increases in upright postural alignment relative to the control condition. Only the Lighten Up instructions led to reduced postural sway, reduced axial postural tone, greater modifiability of tone, and a smoother center of pressure trajectory during step initiation, possibly indicating greater movement efficiency.

CONCLUSION

Mindful movement approaches such as AT may benefit balance and mobility in subjects with PD by acutely facilitating increased upright postural alignment while decreasing rigidity.