Walking Course Research Articles

An observational study of the impact of professional walking aid prescription on gait parameters for individuals with suspected balance impairments

BackgroundThe primary management strategy for gait impairment is the adoption of a walking aid. However, there are no established criteria upon which to base a decision regarding the need for a walking aid. It appears clinicians prescribe aids based on preference, clinical experience and intuition rather than standardised objective rationale. This may contribute to the inconsistent gait response to walking aids reported in the published literature. Understanding gait changes resulting from gait aid usage may have significant impact on clinical practice by improving confidence of prescribing clinicians and compliance of walking aid usage by patients, maximising the benefits of use, and reducing any risks associated with non-use or inappropriate use, of the walking aid. Research questionDo professionally prescribed walking aids improve gait parameters? MethodsThis is a secondary data analysis of a cross-sectional study where participants, identified by healthcare staff requiring a mobility assessment due to potential balance impairment of any cause, walked a 20-m straight walking course under three different walking conditions (no aid, walking stick and 4-wheeled walker). Fifty-eight participants were recruited. Commonly reported spatial and temporal gait parameters were assessed using a validated gait analysis device. Changes in gait parameters across the three conditions were compared, noting the individual's professionally prescribed aid and interpreting changes in parameters towards outcomes of the ‘no aid required group’. Results and significanceGait cycle, cadence, stance, swing and stride length during unaided walking were significantly changed when a walking stick was prescribed (p < 0.05). Stance, swing, double support, stride length, speed, max toe clearance and minimum toe clearance were significantly changed when a 4-wheel walker was prescribed (p < 0.05). Professional walking aid prescription improves some gait parameters. A greater number and magnitude of gait parameter improvements were seen in people requiring a 4-wheel walker than people requiring a walking stick.

The Effect of Ten Weeks of Dual-Task Training on Functional Balance and Gait Speed Under Dual-Task Conditions in Bipolar Patients

Background: In mood disorders, disturbance in balance control and walking is a main motor symptom. Objectives: The aim of this study was to explore the impact of ten weeks of dual-task training on balance and gait speed under dual-task conditions in bipolar patients. Methods: Thirty male patients (age mean 43.13 ± 8.91) with bipolar disorder living in Urmia Psychiatric Center were assigned to the control group and the dual task training group. Dual-task training with moderate intensity, including 20 sessions, 2/week, per 75 min. To detect the changes in the balance and the gait speed, a timed up and go Test (TUG) under dual task conditions and a 10-m walking course under dual task conditions were administered before and after the exercise protocol. It was analyzed using analysis of covariance test. Results: The findings showed that the two groups had significant differences in TUG under motor dual task conditions, gait speed under motor dual task conditions, and gait speed under cognitive dual task conditions (P ≤ 0.05). Conclusions: Considering the effectiveness of cognitive dual-task training in improving gait speed and functional balance, dual-task training may be a potentially important supplement to conventional treatment in people identified as being at high risk of falling.

Test-retest reliability, construct validity and determinants of 6-minute walk test performance in adult patients with asthma

Introduction and objectivesCurrent knowledge regarding the measurement properties of the 6-minute walk test (6MWT) in patients with asthma is limited. Therefore, the aim of this study was to assess the test-retest reliability, measurement error and construct validity of the 6MWT and identify determinants of 6-minute walk distance (6MWD) in patients with asthma. Patients and methods201 asthma patients referred for pre-pulmonary rehabilitation assessment, were retrospectively analyzed (age 61±12 years, 42% male, FEV1 78±27% predicted). Patients performed two 6MWTs on subsequent days using a 30 m straight walking course. Other measurements included resting dyspnea, maximal exercise capacity, body composition, pulmonary function, pulmonary and quadriceps muscle strength and symptoms of anxiety and depression. Measurement error (absolute reliability) was tested using standard error of measurement (SEM), minimal detectable change at 95% confidence interval (MDC95%) and Bland and Altman 95% limits of agreement, whereas test-retest reliability (relative reliability) and construct validity were assessed using the intra-class correlation coefficient (ICC2,1) and correlations, respectively. ResultsThe 6MWD showed excellent test-retest reliability (ICC2,1: 0.91). The mean change in 6MWD after the second 6MWT was 18m (95%CI 11–24m), with 73% of the patients walking further in the second test. The SEM and MDC95% for the 6MWT were 35 m and 98 m, respectively. The best 6MWD correlated strongly with peak oxygen uptake during CPET and resting dyspnea (r = 0.61–0.64) and had no-to-moderate correlations with body composition, pulmonary function, respiratory and quadriceps muscle strength and symptoms of anxiety and depression (r = 0.02-0.45). Multiple linear regression was able to identify maximal workload, BMI, rollator use, maximal expiratory pressure, FEV1 and DLCO as independent determinants of the best 6MWD (R2 = 0.58). ConclusionsThe 6MWT was considered to be reliable and valid in patients with asthma, which strengthens its clinical utility. However, the majority of patients demonstrated a considerable learning effect in the second 6MWT, providing a strong rationale for performing two 6MWTs.

Effect of Walking Course Length on 6MWT: An Experimental Study

Introduction: The 6-minute walk test (6MWT) is a validated tool of submaximal intensity used as an objective measure of functional exercise capacity. Changes in 6-minute walk distance (6MWD) are used to evaluate the efficacy of therapeutic interventions. American Thoracic Society (ATS) guidelines state that the walking course for the 6MWT must be 30 m. In a primary care physiotherapy setting, a 30 m straight course is often not available. Space limitations often force clinicians and researchers to conduct 6MWT on shorter courses. The purpose of this study was to determine the influence of 5, 10, 15, and 30 m course lengths on 6MWD and physiological parameters during the 6MWT. Materials and methods: A total of 80 healthy adults from 18 to 30 years performed four 6MWTs along 5, 10, 15, and 30 m course lengths in a corridor randomly, on consecutive days. The 6MWD and vital parameters on all four course lengths were recorded. Walking speed and maximal oxygen uptake (VO2 max) were calculated. Results: There was a significant difference in 6MWD, walking speed, and VO2 max over 5, 10, 15, and 30 m course lengths during 6MWT (p &lt; 0.05). There was no significant difference observed in the change in heart rate (HR) between 6MWT on 5 and 10 m course lengths and 6MWT on 15 and 30 m course lengths (p &gt; 0.05). Conclusion: The course length strongly influences the performance during the 6MWT and the results on 5, 10, 15, and 30 m courses are not interchangeable with each other. However, there was a similar submaximal cardiac performance on 15 and 30 m course lengths.

Structural Connectivity of Subthalamic Nucleus Stimulation for Improving Freezing of Gait.

Freezing of gait (FOG) is among the most common and disabling symptoms of Parkinson's disease (PD). Studies show that deep brain stimulation (DBS) of the subthalamic nucleus (STN) can reduce FOG severity. However, there is uncertainty about pathways that need to be modulated to improve FOG. To investigate whether STN-DBS effectively reduces FOG postoperatively and whether structural connectivity of the stimulated tissue explains variance of outcomes. We investigated 47 patients with PD and preoperative FOG. Freezing prevalence and severity was primarily assessed using the Freezing of Gait Questionnaire (FOG-Q). In a subset of 18 patients, provoked FOG during a standardized walking course was assessed. Using a publicly available model of basal-ganglia pathways we determined stimulation-dependent connectivity associated with postoperative changes in FOG. A region-of-interest analysis to a priori defined mesencephalic regions was performed using a disease-specific normative connectome. Freezing of gait significantly improved six months postoperatively, marked by reduced frequency and duration of freezing episodes. Optimal stimulation volumes for improving FOG structurally connected to motor areas, the prefrontal cortex and to the globus pallidus. Stimulation of the lenticular fasciculus was associated with worsening of FOG. This connectivity profile was robust in a leave-one-out cross-validation. Subcortically, stimulation of fibers crossing the pedunculopontine nucleus and the substantia nigra correlated with postoperative improvement. STN-DBS can alleviate FOG severity by modulating specific pathways structurally connected to prefrontal and motor cortices. More differentiated FOG assessments may allow to differentiate pathways for specific FOG subtypes in the future.

야외 신체활동 참가자의 신체적 자기개념, 회복탄력성 및 심리적 행복감의 관계

The purpose of this study was to investigate the relationship between physical self-concept, resilience, and psychological well-being of participants in outdoor physical activity. For this purpose, a survey was conducted on people using walking courses around rivers in Seoul and Gyeonggi-do. For the survey, the researcher visited in person, explained the purpose of the study and the contents of the questionnaire in detail, and after obtaining consent, a total of 370 copies of data were collected. Through this procedure, the following results were obtained.<BR> First, in order to understand the relationship between the physical self-concept and resilience of participants in outdoor physical activity, a step-by-step regression analysis was conducted by setting the sub-factor of the physical self-concept as the independent variable and the sub-factor of resilience as the dependent variable. Positivity was positive in body fat, physical activity, competence, and health factors, sociality was positive in body fat, feeling of competence, physical activity, overall body, and control was positive in resilience in body fat, physical activity, competence, health, and overall body factors. Second, satisfaction, which is a sub-factor of physical self-concept and psychological well-being, was significantly explained as positive in health, overall body, and self-esteem factors, and happiness in health, overall body, and physical activity factors of competence. Third, satisfaction and happiness, which are sub-factors of resilience and psychological well-being, were found to be significantly explained as positive in sociality and positivity factors.

Get Moving! Your Brain Will Thank You.

Exercise and cardiovascular fitness are important for physical health and well-being. Recent studies show that exercise is associated with cognitive performance across multiple domains including memory, a common complaint for older adults. Data included a ten-word list of delayed recall, a clock drawing activity, and a three-meter walking course derived from the National Health & Aging Trends Study Database (NHATS Round 9). A total of 4977 participants were included in the analysis which was predominantly white (69.7%), non-Hispanic (94.5%), female (59.2%), and between the ages of 70-84 (62.7%). A hierarchical linear regression revealed that performance on the three-meter walking course positively predicted performance on delayed recall, F(4,3999)=300.257, p<.001, and on the clock drawing activity, which is a common screening task for cognitive decline, F(4,3978)=156.433, p<.001; accounting for 23.1% and 13.6% of the variability, respectively, over and above known demographic variables. Findings suggest that fitness may be one of many factors that is associated with memory and overall cognitive decline. These findings are timely as many individuals slowed down as a result of the COVID-19 pandemic, resulting in decreases in exercise and physical activity. Not being physically active or exercising may be related to poorer physical and cognitive health, with specific concerns regarding memory. Taking into consideration the fear and anxiety associated with declining memory in late life, it is crucial to explore this area further along with other factors that may contribute to the association and develop new ways for older adults to exercise safely during the COVID-19 pandemic.

Kurort Health Walking Preferentially Decreases Higher Blood Pressure and Improves Mood.

Background: Kurort is a German term from the words kur (cure) and ort (area), and refers to improvements in patients’ health in areas full of nature. We investigated the effect of kurort health walking in the 2 urban-style kurort health walking courses opened in Gifu City on systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate, and mood.Methods and Results: The subjects were 454 people (136 males, 318 females; mean [±SD] age 61.7±9.9 years) taking part in kurort health walking for the first time. SBP, DBP, and heart rate were measured before and after kurort health walking. Mood was assessed using a 10-item checklist after kurort health walking. Kurort health walking significantly decreased SBP and DBP and increased heart rate. The decrease in SBP was significantly greater in the SBP ≥140 than <140 mmHg group, indicating that SBP before Kurort health walking was inversely correlated with the change in SBP. Similarly, the decrease in DBP was significantly greater in the DBP ≥90 than <90 mmHg group, indicating that DBP before kurort health walking was also inversely correlated with the change in DBP. All 10 items on the mood assessment were significantly improved after kurort health walking.Conclusions: Kurort health walking preferentially decreases higher blood pressure and improves mood.

The Incremental Shuttle Walk Test

The Incremental Shuttle Walk Test

Personification of nordic walking course in children with bronchial asthma depending on physical health level and disease control

Objective. To evaluate the effectiveness of a personalized Nordic walking course in children with bronchial asthma.&#x0D; Material and methods. In conditions of a local sanatorium, 60 children aged 814 years with atopic bronchial asthma in remission were examined, 30 patients received the usual set of health-improving measures (comparison group), 30 patients additionally underwent a course of sports walking, personalized depending on the degree of asthma control and the level of physical health (main group). To evaluate it, the method of L.G. Apanasenko was used. Indicators of external respiration, abdominal and back muscle strength, physical performance, and Robinson and Rufier indices were determined. The children were examined twice: before and after the rehabilitation course. The dynamics of functional indicators was expressed as a percentage increase in relation to the initial values.&#x0D; Results. It was found that 36.7 % of patients had a low, 53.3 % average and only 10 % high level of physical health. Only 10 % had a complete asthma control, and 90 % of children had a partial control. The use of a personalized sports walking course helped to improve the functional parameters of external respiration, muscular and cardiovascular systems. In the comparison group, the positive dynamics of most of functional indicators was significantly less obvious.&#x0D; Conclusions. The course of Nordic walking in children with bronchial asthma at the stage of rehabilitation should be personalized taking into account the level of physical health and the degree of disease control. This technology in this category of patients has a significant positive health-strengthening effect, which is manifested by improving the functional state of the muscular, respiratory and cardiovascular systems.

Mapping of electrodermal activity (EDA) during outdoor community-level mobility tasks in individuals with lower-limb amputation.

IntroductionBalance confidence and perception of task challenge is an important construct to measure in rehabilitation of people with lower-limb amputation (LLA). Measurement of electrodermal activity (EDA) captures physiological arousal responses reflecting an individual’s perceived challenge in a task. This study explores the feasibility of the use of EDA during outdoor walking tasks to capture task-specific physiological arousal changes associated with perception of challenge in people with amputation.ObjectiveTo develop and demonstrate feasibility of a portable EDA/GPS system mapping physiological arousal while challenging walking balance outdoors in individuals with LLA and controls.MethodsSixteen people (eight with LLA and eight age-/sex-matched controls) completed an outdoor walking course in the community (3 laps). A battery-powered portable device was developed containing EDA/GPS sensors with data logged on a microcontroller. Phasic EDA response was extracted from EDA signal to explore the physiological arousal response to walking tasks.ResultsPhysiological arousal demonstrated task-specific modulation with ascending stairs without a handrail showing higher levels of phasic EDA than walking on a paved incline (p = 0.01) or a gravel decline (p = 0.01) in people with LLA. While evidence of habituation over repeated trials was shown in controls with lap 1 of walking down a gravel decline showing higher levels of phasic EDA than lap 3 (p = 0.01). Phasic EDA maps, representative of arousal levels throughout the walking course, showed individual-specific response.ConclusionMapping of EDA during outdoor walking is feasible. Modulation of physiological arousal between outdoor walking tasks and over repeated trials is suggestive of clinical utility. Further research is warranted to explore how EDA may be incorporated into assessment of response to outdoor walking amongst individuals following LLA.

Nordic walking in winter as the multitask training in patients with Parkinson's disease

To evaluate an influence of 8-week course of winter nordic walking as the multitask on the spatial-temporal characteristics of walking and motor disturbances in patients with Parkinson's disease (PD). Eleven patients (3 men and 8 women, mean age 66.82±3.97 years) with Hoehn and Yahr stage 1 to 2 PD were included in the study. Preliminary medical examination, including the anthropometric profile with the calculation of the body mass index (BMI), the grip strength on the right and left sides, spirometry, functional tests with the physical load (orthostatic test with the determination of systolic and diastolic blood pressure (SBP and DPB) and type of reaction (normal, hypertonic, hypotonic), the 6 Minute Walk Test, timed Up and Go test), was performed to evaluate the physical state. The evaluation of motor function was performed using the unified Parkinson's disease rating scale of the Movement Disorder Society (MDS UPDRS), part III. A 8-week course of nordic walking training was carried out at the certified track on the stadium localized outside of the city, in the wood and parks area in the winter. Compared to the first training, gait velocity increased at the 3rd session, the step length at the 6th. The improvement of the spatial-temporal characteristics of walking was accompanied by the improvement of the motor function as measured by MDS UPDRS, part III. Winter nordic walking as multitask is the effective measure of exercise treatment in patients with PD, because it improves the spatial-temporal characteristics of walking and the motor function.

Abstract 13462: 6-minute Walk Test Variability May be Reduced by a Structured Training and Monitoring Program, Potentially Facilitating Detection of Treatment Effects

Background: The 6-minute walk test (6MWT) is well established for evaluation of functional exercise capacity in patients with conditions such as pulmonary hypertension, peripheral arterial disease and heart failure. Its popularity as an endpoint in heart failure trials has increased in parallel with health authority acceptance of the test as a measure of patients' function. Minimizing variability is key to the successful conduct and outcome of trials with 6MWT endpoints. We assessed the impact on walking distance variability of a structured training and monitoring program Methods: After systematically observing conduct of 6MWT worldwide, our core lab developed a multifaceted approach including inspection and standardization of the walking course, standardized training, review of the first 3 tests for each test administrator and random tests thereafter, standardized data collection methods, and assessment of intra-test inconsistencies with feedback. Variability of walking distance using this structured approach is descriptively compared with 6MWT data from the literature. Results: In a multicenter trial which used the structured program, the standard deviation (SD) of distance walked was 21.7% of the mean at baseline and 22.6% at Week 4 (Table). For comparison, we reviewed 2018-19 reports of 6MWT not utilizing this structured approach and identified 5 multicenter studies of patients with heart failure which reported mean and SD of distance walked (Table). Baseline distance walked ranged from 104 to 385 m (weighted mean 220.4 m); SD of distance walked ranged from 28% to 135% of distance walked (weighted mean 70.9%). Conclusion: Standardization of the 6MWT walking course, structured training of test administrators and monitoring of test quality may reduce test variability which could improve accuracy of treatment effect assessment and possibly require smaller sample sizes.

A Cross-species Model of Dual-Task Walking in Young and Older Humans and Rats.

Introduction: Dual-task walking is common in daily life but becomes more difficult with aging. Little is known about the neurobiological mechanisms affecting competing cognitive demands. Translational studies with human and animal models are needed to address this gap. This pilot study investigated the feasibility of implementing a novel cross-species dual-task model in humans and rats and aimed to establish preliminary evidence that the model induces a dual-task cost.Methods: Young and older humans and rats performed an object discrimination task (OD), a baseline task of typical walking (baseline), an alternation turning task on a Figure 8 walking course (Alt), and a dual-task combining object discrimination with the alternation task (AltOD). Primary behavioral assessments including walking speed and correct selections for object discrimination and turning direction. In humans, left prefrontal cortex activity was measured with functional near-infrared spectroscopy (fNIRS).Results: Human subjects generally performed well on all tasks, but the older adults exhibited a trend for a slowing of walking speed immediately before the turning decision for Alt and AltOD compared to baseline. Older adults also had heightened prefrontal activity relative to young adults for the Alt and AltOD tasks. Older rodents required more training than young rodents to learn the alternation task. When tested on AltOD with and without a 15-s delay between trials, older rodents exhibited a substantial performance deficit for the delayed version on the initial day of testing. Old rats, however, did not show a significant slowing in walking speed with increasing task demand, as was evident in the young rats.Discussion: This study demonstrates the feasibility and challenges associated with implementing a cross-species dual-task model. While there was preliminary evidence of dual-task cost in both humans and rats, the magnitude of effects was small and not consistent across species. This is likely due to the relative ease of each task in humans and the walking component in rats not being sufficiently challenging. Future versions of this test should make the cognitive tasks more challenging and the motor task in rats more complex.

Impact Of A Dog Walking Course On College Students’ Physical Activity

The increase in sedentary behaviors, poor dietary choices, and academic time demands during college or university is well documented. Physical activity-related service-learning curricula offers a way to circumvent the negative effects of these increases by providing students with physical activity, as well as the opportunity to learn responsibility, life skills, and values associated with larger social issues. Research identifies the positive effects of dog walking for both dogs and humans. Shelter dogs, in particular, benefit from this physical activity because of their stressful surroundings and need for physical and psychological activity. PURPOSE: The purpose of this study was to compare physical activity (PA) levels of students enrolled in a standard PA course and students enrolled in a service-learning PA course where shelter dogs were walked by students. METHODS: College students enrolled in a standard fitness walking course (N = 46; 74% females) and a fitness dog walking course (N = 19; 68 % females) wore NL-1000 pedometers 2 times/week during their 50 minute class session. Data was collected across 30 and 32 course sessions, respectively. Means and stand deviations were calculated and an independent t-test was performed. RESULTS: Students in the standard fitness walking course acquired approximately 1760.9 steps ± 640.9, walked an average of .83 miles ± .3) and acquired approximately 7.6 minutes ± 4.2) of moderate to vigorous PA. Students enrolled in the fitness dog walking course acquired approximately 4406.0 steps ± 317.9, walked an average of .2.1 miles ± .16 and acquired approximately 26.2 minutes ± 3.2) of moderate to vigorous PA. There was a significant difference in steps (t(60) = 20.8, p < .000, d = 5.2), distance (t(60) = 20.9, p < .000, d = 5.3, and minutes (t(60) = 19.7, p < .000, d = 5.0) of moderate to vigorous PA between courses. CONCLUSION: Students enrolled in a service-learning PA course walked significantly more steps, distance, and minutes than students enrolled in a traditional PA course. Notably, students in the dog walking course reached approximately 40% of their recommended step requirements during class time. The local shelter dogs also benefitted from being physically active demonstrating the utility of community engagement when seeking innovative ways to promote PA among college students.

Ten-year disease progression in multiple sclerosis: walking declines more rapidly than arm and hand function

Background and aimsFrom a clinical perspective there is a difference in the decline of arm and hand function and leg function in patients with multiple sclerosis (PwMS). Therefore, this study investigated the course of walking and arm and hand functions in PwMS over the first 10 years after diagnosis, including whether any function declined earlier or faster. MethodsA long-term prospective follow-up study of an incidence cohort of 156 patients with a definite diagnosis of MS, either non-relapse onset (n=28) or relapse onset (n=128) type. Participants were systematically examined immediately after definite diagnosis, at 6 months, and at 1, 2, 3, 6 and 10 years. Walking was determined with the fast 10-meter timed walk test (10mTWT), arm and hand function with the Action Research Arm test (ARAT) and the nine-hole peg test (9HPT). The 10-year trajectories of walking and arm and hand functions were compared using standardized z-scores. ResultsFrom 3 years onwards the z-scores of the arm and leg function were visually diverging, with a trend towards significance at 6 years, and at 10 years the 10mTWT z-score is significantly higher than the 9HPT. This difference is more pronounced in non-relapse onset patients than in patients with relapse onset type MS, but present in both groups over the first 10 years. In the non-relapse onset group a difference in z-scores at 10 years post-diagnosis between the 10m TWT and 9HPT was found of -12.94 (95% confidence interval (CI) -20.2 to -5.73) for the right and -10.14 (95% CI -17.3 to -2.93) for the left hand. In the relapse onset group there was a difference at 10 years post-diagnosis of -2.17 (95% CI -3.75 to -0.59) for the right and a difference of -2.29 (95% CI -3.87 to -0.71) for the left hand. ConclusionThis is the first longitudinal study that shows that walking declines earlier and more rapidly than arm and hand function in patients with MS. These results give important insights that can be linked to the pathophysiological disease process regarding the ascending order of deterioration in patients with MS.

Physiological and Psychological Effects of Walking in Urban Parks and Its Imagery in Different Seasons in Middle-Aged and Older Adults: Evidence from Matsudo City, Japan

The benefits of park therapy have been investigated in young adults, but rarely for middle-aged and older adults. This study evaluates the physiological and psychological effects of walking in urban parks and park therapy images in winter, spring, and early summer. The experiments were implemented in two walking courses in the urban park in Japan and involved 12 middle-aged and older adults. Participants walked on walking courses in an urban park and city street for 11–15 min. Their heart rate and blood pressure were evaluated to determine physiological responses. The Profile of Mood States (POMS), State-Trait Anxiety Inventory (STAI), and Landscape Image Sketching Technique (LIST) were used to determine psychological responses and spatial conditions. Walking in an urban park exhibited lower heart rates and blood pressure as compared to walking in the city. It was congruent with lowered negative moods, total mood disturbance (TMD) scores, and state anxiety, while the higher positive mood was observed in the urban parks as compared to the city. Images in winter displayed trees, relaxation, and comfort; in spring, water, activity, people, surrounding place, and recreational space; and in early summer, greenery, lawn, and broadness. In conclusion, walking in urban parks leads to physiological, psychological relaxation, and varied landscape appreciation.

The Short Physical Performance Battery (ASSESSMENT)

The Short Physical Performance Battery (ASSESSMENT)

WITHDRAWN: The optical multi-camera based motion Analysis of Walking Attitude Stability of Lower Limb Exoskeleton Robot using movement image segmentation

Abstract Aiming at the stable walking problem of lower limb exoskeleton robot, the instability mechanism of the robot during walking is analyzed based on the zero-moment point theory. It is found that the zero-moment point theory has certain limitations in a complete walking cycle. Based on this, the stability criterion of the biped projection polygon method is proposed, and the stable polygon in the walking process is established. The segmentation method is used to divide the stable polygon of each pose into several triangles, and the point Zero Moment Point (ZMP) law changes of zero-moment in a walking cycle is analyzed, qualitatively determine the dynamic stability characteristics of the human-machine system. Based on the shortest distance stability margin, the concept of instability rate is proposed. Based on several stable triangles, the dynamic stability characteristics are quantitatively calculated. The optical multi-camera motion capture system, which is a multi-media measurement technology, is used to collect the gravity center data of the human-machine system in the course of walking. The multi-media technology is used to process the data and provide the test data.The experimental results show that by calculating the stability criterion and instability rate of the biped projection polygon method are obtained, more accurate expression of the stability characteristics of the human-machine system in the walking posture motion cycle can be expressed.

Energetics of Walking With a Robotic Knee Exoskeleton.

The authors tested 4 young healthy subjects walking with a powered knee exoskeleton to determine if it could reduce the metabolic cost of locomotion. Subjects walked with a backpack loaded and unloaded, on a treadmill with inclinations of 0° and 15°, and outdoors with varied natural terrain. Participants walked at a self-selected speed (average 1.0m/s) for all conditions, except incline treadmill walking (average 0.5m/s). The authors hypothesized that the knee exoskeleton would reduce the metabolic cost of walking uphill and with a load compared with walking without the exoskeleton. The knee exoskeleton reduced metabolic cost by 4.2% in the 15° incline with the backpack load. All other conditions had an increase in metabolic cost when using the knee exoskeleton compared with not using the exoskeleton. There was more variation in metabolic cost over the outdoor walking course with the knee exoskeleton than without it. Our findings indicate that powered assistance at the knee is more likely to decrease the metabolic cost of walking in uphill conditions and during loaded walking rather than in level conditions without a backpack load. Differences in positive mechanical work demand at the knee for varying conditions may explain the differences in metabolic benefit from the exoskeleton.