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Sample records for group began walking

  1. Groups, graphs and random walks

    CERN Document Server

    Salvatori, Maura; Sava-Huss, Ecaterina

    2017-01-01

    An accessible and panoramic account of the theory of random walks on groups and graphs, stressing the strong connections of the theory with other branches of mathematics, including geometric and combinatorial group theory, potential analysis, and theoretical computer science. This volume brings together original surveys and research-expository papers from renowned and leading experts, many of whom spoke at the workshop 'Groups, Graphs and Random Walks' celebrating the sixtieth birthday of Wolfgang Woess in Cortona, Italy. Topics include: growth and amenability of groups; Schrödinger operators and symbolic dynamics; ergodic theorems; Thompson's group F; Poisson boundaries; probability theory on buildings and groups of Lie type; structure trees for edge cuts in networks; and mathematical crystallography. In what is currently a fast-growing area of mathematics, this book provides an up-to-date and valuable reference for both researchers and graduate students, from which future research activities will undoubted...

  2. Random walks on reductive groups

    CERN Document Server

    Benoist, Yves

    2016-01-01

    The classical theory of Random Walks describes the asymptotic behavior of sums of independent identically distributed random real variables. This book explains the generalization of this theory to products of independent identically distributed random matrices with real coefficients. Under the assumption that the action of the matrices is semisimple – or, equivalently, that the Zariski closure of the group generated by these matrices is reductive - and under suitable moment assumptions, it is shown that the norm of the products of such random matrices satisfies a number of classical probabilistic laws. This book includes necessary background on the theory of reductive algebraic groups, probability theory and operator theory, thereby providing a modern introduction to the topic.

  3. Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

    Directory of Open Access Journals (Sweden)

    Sara L. Warber

    2013-10-01

    Full Text Available The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708 were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale, depression (Major Depressive Inventory, perceived stress (Perceived Stress Scale and emotional well-being (Positive and Negative Affect Schedule. Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through “green prescriptions” to improve psychological and emotional well-being, as well as physical activity.

  4. The role of walkers' needs and expectations in supporting maintenance of attendance at walking groups: a longitudinal multi-perspective study of walkers and walk group leaders.

    Directory of Open Access Journals (Sweden)

    Aikaterini Kassavou

    Full Text Available There is good evidence that when people's needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers' needs and walk leaders' actions to address them. The present study was aimed at addressing both of these gaps in the research.Two preliminary thematic analyses were conducted on face-to-face interviews with (a eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders.Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers' personalities. Walk leaders reported a lack of efficacy to effectively address walkers' needs.Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers' maintenance at walking groups. This should result in greater retention of walkers in walking

  5. The walking behaviour of pedestrian social groups and its impact on crowd dynamics

    CERN Document Server

    Moussaid, Mehdi; Garnier, Simon; Helbing, Dirk; Theraulaz, Guy

    2010-01-01

    Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behavior consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We ...

  6. The Walking Behaviour of Pedestrian Social Groups and Its Impact on Crowd Dynamics

    Science.gov (United States)

    Moussaïd, Mehdi; Perozo, Niriaska; Garnier, Simon; Helbing, Dirk; Theraulaz, Guy

    2010-01-01

    Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its “non-aerodynamic” shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals. PMID:20383280

  7. The walking behaviour of pedestrian social groups and its impact on crowd dynamics.

    Directory of Open Access Journals (Sweden)

    Mehdi Moussaïd

    Full Text Available Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its "non-aerodynamic" shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals.

  8. Position-space renormalization-group approach to the resistance of random walks

    Science.gov (United States)

    Sahimi, Muhammad; Jerauld, Gary R.; Scriven, L. E.; Davis, H. Ted

    1984-06-01

    We consider a Pólya random walk, i.e., an unbiased, nearest-neighbor walk, on a d-dimensional hypercubic lattice and study the scaling behavior of the mean end-to-end resistance of the walk as a function of the number of steps in the walk. The resistance of the walk is generated by assigning a constant conductance to each step of the walk. This problem was recently proposed by Banavar, Harris, and Koplik, and may be useful for understanding the physics of disordered systems. We develop a position-space renormalization-group approach, a generalization of the one developed for percolation conductivity, and study the problem and a modification of it proposed here in one, two, and three dimensions. Our results are in good agreement with the numerical estimates of Banavar et al.

  9. Older Adults with Visual Impairment: Lived Experiences and a Walking Group

    Science.gov (United States)

    Green, Clare; Miyahara, Motohide

    2007-01-01

    The authors investigated past and present physical activities of 6 older individuals with diverse types of visual impairment who participated in a walking group. The authors identified the participants' lived experiences of visual impairment and physical activity through interviews and assessed their current activity levels by using pedometers.…

  10. Harmonic maps on amenable groups and a diffusive lower bound for random walks

    CERN Document Server

    Lee, James R

    2009-01-01

    We prove that on any infinite, connected, locally finite, transitive graph G, the probability of the random walk being within $\\eps \\sqrt{t}$ of the origin after t steps is at most $O(\\eps)$. A similar statement holds for finite graphs, up to the relaxation time of the walk. Our approach uses non-constant equivariant harmonic mappings taking values in a Hilbert space. For the special case of discrete, amenable groups, we present a more explicit proof of the Mok-Korevaar-Schoen theorem on existence of such harmonic maps by constructing them from the heat flow on a Folner set.

  11. Use of formative research and social network theory to develop a group walking intervention: Sumter County on the Move!

    Science.gov (United States)

    Forthofer, Melinda; Burroughs-Girardi, Ericka; Stoisor-Olsson, Liliana; Wilcox, Sara; Sharpe, Patricia A; Pekuri, Linda M

    2016-10-01

    Although social support is a frequently cited enabler of physical activity, few studies have examined how to harness social support in interventions. This paper describes community-based formative research to design a walking program for mobilizing naturally occurring social networks to support increases in walking behavior. Focus group methods were used to engage community members in discussions about desired walking program features. The research was conducted with underserved communities in Sumter County, South Carolina. The majority of focus group participants were women (76%) and African American (92%). Several important themes emerged from the focus group results regarding attitudes toward walking, facilitators of and barriers to walking, ideal walking program characteristics, and strategies for encouraging community members to walk. Most noteably, the role of existing social networks as a supportive influence on physical activity was a recurring theme in our formative research and a gap in the existing evidence base. The resulting walking program focused on strategies for mobilizing, supporting and reinforcing existing social networks as mechanisms for increasing walking. Our approach to linking theory, empirical evidence and community-based formative research for the development of a walking intervention offers an example for practitioners developing intervention strategies for a wide range of behaviors.

  12. Immigrant families' perceptions on walking to school and school breakfast: a focus group study

    Directory of Open Access Journals (Sweden)

    Busby Katie

    2007-12-01

    Full Text Available Abstract Background Immigrant children face an increased risk of being overweight. Little is known about how immigrant families perceive school programs that may help prevent obesity, such as walking to school and school breakfast. Methods Six focus groups (n = 53 were conducted with immigrant parents of school-aged children, two each in three languages: Vietnamese, Spanish, and Somali. A facilitator and translator conducted the focus groups using a script and question guide. Written notes and audio transcripts were recorded in each group. Transcripts were coded for themes by two researchers and findings classified according to an ecological model. Results Participants in each ethnic group held positive beliefs about the benefits of walking and eating breakfast. Barriers to walking to school included fear of children's safety due to stranger abductions, distrust of neighbors, and traffic, and feasibility barriers due to distance to schools, parent work constraints, and large families with multiple children. Barriers to school breakfast participation included concerns children would not eat due to lack of appealing/appropriate foods and missing breakfast due to late bus arrival or lack of reminders. Although some parents acknowledged concerns about child and adult obesity overall, obesity concerns did not seem personally relevant. Conclusion Immigrant parents supported the ideals of walking to school and eating breakfast, but identified barriers to participation in school programs across domains of the ecological model, including community, institution, and built environment factors. Schools and communities serving immigrant families may need to address these barriers in order to engage parents and children in walking and breakfast programs.

  13. Changing the demand on specific muscle groups affects the walk-run transition speed.

    Science.gov (United States)

    Bartlett, Jamie L; Kram, Rodger

    2008-04-01

    It has been proposed that muscle-specific factors trigger the human walk-run transition. We investigated if changing the demand on trigger muscles alters the preferred walk-run transition speed. We hypothesized that (1) reducing the demand on trigger muscles would increase the transition speed and (2) increasing the demand on trigger muscles would decrease the transition speed. We first determined the normal preferred walk-run transition speed (PTS) using a step-wise protocol with a randomized speed order. We then determined PTS while subjects walked with external devices that decreased or increased the demand on specific muscle groups. We concurrently measured the electromyographic activity of five leg muscles (tibialis anterior, soleus, rectus femoris, medial and lateral gastrocnemius) at each speed and condition. For this study, we developed a dorsiflexor assist device that aids the dorsiflexor muscles. A leg swing assist device applied forward pulling forces at the feet thus aiding the hip flexors during swing. A third device applied a horizontal force near the center of mass, which impedes or aids forward progression thus overloading or unloading the plantarflexor muscles. We found that when demand was decreased in the muscles measured, the PTS significantly increased. Conversely, when muscle demand was increased in the plantar flexors, the PTS decreased. However, combining assistive devices did not produce an even faster PTS. We conclude that altering the demand on specific muscles can change the preferred walk-run transition speed. However, the lack of a summation effect with multiple external devices, suggests that another underlying factor ultimately determines the preferred walk-run transition speed.

  14. Effect of group walking traffic on dynamic properties of pedestrian structures

    Science.gov (United States)

    Shahabpoor, E.; Pavic, A.; Racic, V.; Zivanovic, S.

    2017-01-01

    The increasing number of reported vibration serviceability problems in newly built pedestrian structures, such as footbridges and floors, under walking load has attracted considerable attention in the civil engineering community over the past two decades. The key design challenges are: the inter- and intra-subject variability of walking people, the unknown mechanisms of their interaction with the vibrating walking surfaces and the synchronisation between individuals in a group. Ignoring all or some of these factors makes the current design methods an inconsistent approximation of reality. This often leads to considerable over- or under-estimation of the structural response, yielding an unreliable assessment of vibration performance. Changes to the dynamic properties of an empty structure due to the presence of stationary people have been studied extensively over the past two decades. The understanding of the similar effect of walking people on laterally swaying bridges has improved tremendously in the past decade, due to considerable research prompted by the Millennium Bridge problem. However, there is currently a gap in knowledge about how moving pedestrians affect the dynamic properties of vertically vibrating structures. The key reason for this gap is the scarcity of credible experimental data pertinent to moving pedestrians on vertically vibrating structures, especially for multi-pedestrian traffic. This paper addresses this problem by studying the dynamic properties of the combined human-structure system, i.e. occupied structure damping ratio, natural frequency and modal mass. This was achieved using a comprehensive set of frequency response function records, measured on a full-scale test structure, which was occupied by various numbers of moving pedestrians under different walking scenarios. Contrary to expectations, it was found that the natural frequency of the joint moving human-structure system was higher than that of the empty structure, while it was

  15. The effects of walking on golf drive performance in two groups of golfers with different skill levels

    Directory of Open Access Journals (Sweden)

    Andrew Green

    2015-04-01

    Full Text Available Although walking is a fundamental part of the game of golf, the effects of walking on the golf shots outcome are largely overlooked. The purpose of the present study was to determine the effects of a hole-to-hole distance walk on the golf drive performance as well as possible physiological contributory factors were evaluated. Twenty-one volunteer golfers were recruited and divided into two groups based on their average round scores: More competitive Golfer (McG ≤88 (n=13 and Irregular Social Golfer (ISG ≥89 (n=8. Drive distance was directly measured. Balance and hand-eye coordination were assessed using a modified stork test and a customized three dimension- al maze. Participants hit 10 golf balls and then walked 500m before repeating the tests. Heart rates of golfers before driving weren’t different between groups, but were elevated within the groups following walking. The McG had longer drives following the walk (p=0.018. The change in the distance was correlated to the change in right leg balance with eyes closed (r=- 0.619 p=0.003. Biomechanical changes were correlated to the change in drive distance (r=0.867 p=0.025. This study shows that an aerobic warm-up prior to a round or small amounts of walking early in a round may be beneficial to golfers of better ability.

  16. Conformal or Walking? Monte Carlo renormalization group studies of SU(3) gauge models with fundamental fermions

    CERN Document Server

    Hasenfratz, Anna

    2010-01-01

    Strongly coupled gauge systems with many fermions are important in many phenomenological models. I use the 2-lattice matching Monte Carlo renormalization group method to study the fixed point structure and critical indexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions. With an improved renormalization group block transformation I am able to connect the perturbative and confining regimes of the N_f=8 flavor system, thus verifying its QCD-like nature. With N_f=12 flavors the data favor the existence of an infrared fixed point and conformal phase, though the results are also consistent with very slow walking. I measure the anomalous mass dimension in both systems at several gauge couplings and find that they are barely different from the free field value.

  17. Honeybee drones are attracted by groups of consexuals in a walking simulator.

    Science.gov (United States)

    Brandstaetter, Andreas Simon; Bastin, Florian; Sandoz, Jean-Christophe

    2014-04-15

    During the mating season, honeybee males, the drones, gather in congregation areas 10-40 m above ground. When a receptive female, a queen, enters the congregation, drones are attracted to her by queen-produced pheromones and visual cues and attempt to mate with the queen in mid-air. It is still unclear how drones and queens find the congregations. Visual cues on the horizon are most probably used for long-range orientation. For shorter-range orientation, however, attraction by a drone-produced aggregation pheromone has been proposed, yet so far its existence has not been confirmed conclusively. The low accessibility of congregation areas high up in the air is a major hurdle and precise control of experimental conditions often remains unsatisfactory in field studies. Here, we used a locomotion compensator-based walking simulator to investigate drones' innate odor preferences under controlled laboratory conditions. We tested behavioral responses of drones to 9-oxo-2-decenoic acid (9-ODA), the major queen-produced sexual attractant, and to queen mandibular pheromone (QMP), an artificial blend of 9-ODA and several other queen-derived components. While 9-ODA strongly dominates the odor bouquet of virgin queens, QMP rather resembles the bouquet of mated queens. In our assay, drones were attracted by 9-ODA, but not by QMP. We also investigated the potential attractiveness of male-derived odors by testing drones' orientation responses to the odor bouquet of groups of 10 living drones or workers. Our results demonstrate that honeybee drones are attracted by groups of other drones (but not by workers), which may indicate a role of drone-emitted cues for the formation of congregations.

  18. Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans

    DEFF Research Database (Denmark)

    Grey, Michael James; Ladouceur, Michel; Andersen, Jacob B.

    2001-01-01

    1. The objective of this study was to determine which afferents contribute to the medium latency response of the soleus stretch reflex resulting from an unexpected perturbation during human walking. 2. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h(-1) with the left ankle...... component (P = 0.004), whereas the medium latency component was unchanged (P = 0.437). 6. Two hours after the ingestion of tizanidine, an alpha(2)-adrenergic receptor agonist known to selectively depress the transmission in the group II afferent pathway, the medium latency reflex was strongly depressed (P...... = 0.007), whereas the short latency component was unchanged (P = 0.653). 7. An ankle block with lidocaine hydrochloride was performed to suppress the cutaneous afferents of the foot and ankle. Neither the short (P = 0.453) nor medium (P = 0.310) latency reflexes were changed. 8. Our results support...

  19. Moving beyond green: exploring the relationship of environment type and indicators of perceived environmental quality on emotional well-being following group walks.

    Science.gov (United States)

    Marselle, Melissa R; Irvine, Katherine N; Lorenzo-Arribas, Altea; Warber, Sara L

    2014-12-23

    Against the backdrop of increasing interest in the relationship between Nature and health, this study examined the effect of perceived environment type and indicators of perceived environmental quality on short-term emotional well-being following outdoor group walks. Participants (n = 127) of a national group walk program completed pre- and post-walk questionnaires for each walk attended (n = 1009) within a 13-week study period. Multilevel linear modelling was used to examine the main and moderation effects. To isolate the environmental from the physical activity elements, analyses controlled for walk duration and perceived intensity. Analyses revealed that perceived restorativeness and perceived walk intensity predicted greater positive affect and happiness following an outdoor group walk. Perceived restorativeness and perceived bird biodiversity predicted post-walk negative affect. Perceived restorativeness moderated the relationship between perceived naturalness and positive affect. Results suggest that restorative quality of an environment may be an important element for enhancing well-being, and that perceived restorativeness and naturalness of an environment may interact to amplify positive affect. These findings highlight the importance of further research on the contribution of environment type and quality on well-being, and the need to control for effects of physical activity in green exercise research.

  20. Trunk motion and gait characteristics of pregnant women when walking: report of a longitudinal study with a control group.

    Science.gov (United States)

    Gilleard, Wendy L

    2013-03-20

    A longitudinal repeated measures design over pregnancy and post-birth, with a control group would provide insight into the mechanical adaptations of the body under conditions of changing load during a common female human lifespan condition, while minimizing the influences of inter human differences. The objective was to investigate systematic changes in the range of motion for the pelvic and thoracic segments of the spine, the motion between these segments (thoracolumbar spine) and temporospatial characteristics of step width, stride length and velocity during walking as pregnancy progresses and post-birth. Nine pregnant women were investigated when walking along a walkway at a self-selected velocity using an 8 camera motion analysis system on four occasions throughout pregnancy and once post birth. A control group of twelve non-pregnant nulliparous women were tested on three occasions over the same time period. The existence of linear trends for change was investigated. As pregnancy progresses there was a significant linear trend for increase in step width (p = 0.05) and a significant linear trend for decrease in stride length (p = 0.05). Concurrently there was a significant linear trend for decrease in the range of motion of the pelvic segment (p = 0.03) and thoracolumbar spine (p = 0.01) about a vertical axis (side to side rotation), and the pelvic segment (p = 0.04) range of motion around an anterio-posterior axis (side tilt). Post-birth, step width readapted whereas pelvic (p = 0.02) and thoracic (p changes was greater than that accounted for with natural variability with re testing. As pregnancy progressed and post-birth there were significant linear trends seen in biomechanical changes when walking at a self-determined natural speed that were greater than that accounted for by natural variability with repeated testing. Not all adaptations were resolved by eight weeks post birth.

  1. Feasibility and Safety of a Powered Exoskeleton for Assisted Walking for Persons With Multiple Sclerosis: A Single-Group Preliminary Study.

    Science.gov (United States)

    Kozlowski, Allan J; Fabian, Michelle; Lad, Dipan; Delgado, Andrew D

    2017-07-01

    To examine the feasibility, safety, and secondary benefit potential of exoskeleton-assisted walking with one device for persons with multiple sclerosis (MS). Single-group longitudinal preliminary study with 8-week baseline, 8-week intervention, and 4-week follow-up. Outpatient MS clinic, tertiary care hospital. Participants (N=13; age range, 38-62y) were mostly women with Expanded Disability Status Scale scores ranging from 5.5 to 7.0. Exoskeleton-assisted walk training. Primary outcomes were accessibility (enrollment/screen pass), tolerability (completion/dropout), learnability (time to event for standing, walking, and sitting with little or no assistance), acceptability (satisfaction on the device subscale of the Quebec User Evaluation of Satisfaction with Assistive Technology version 2), and safety (event rates standardized to person-time exposure in the powered exoskeleton). Secondary outcomes were walking without the device (timed 25-foot walk test and 6-minute walk test distance), spasticity (Modified Ashworth Scale), and health-related quality of life (Patient-Reported Outcomes Measurement and Information System pain interference and Quality of Life in Neurological Conditions fatigue, sleep disturbance, depression, and positive affect and well-being). The device was accessible to 11 and tolerated by 5 participants. Learnability was moderate, with 5 to 15 sessions required to walk with minimal assistance. Safety was good; the highest adverse event rate was for skin issues at 151 per 1000 hours' exposure. Acceptability ranged from not very satisfied to very satisfied. Participants who walked routinely improved qualitatively on sitting, standing, or walking posture. Two participants improved and 2 worsened on ≥1 quality of life domain. The pattern of spasticity scores may indicate potential benefit. The device appeared feasible and safe for about a third of our sample, for whom routine exoskeleton-assisted walking may offer secondary benefits. Copyright

  2. Virtually Abelian quantum walks

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    Mauro D'Ariano, Giacomo; Erba, Marco; Perinotti, Paolo; Tosini, Alessandro

    2017-01-01

    We study discrete-time quantum walks on Cayley graphs of non-Abelian groups, focusing on the easiest case of virtually Abelian groups. We present a technique to reduce the quantum walk to an equivalent one on an Abelian group with coin system having larger dimension. This method allows one to extend the notion of wave-vector to the virtually Abelian case and study analytically the walk dynamics. We apply the technique in the case of two quantum walks on virtually Abelian groups with planar Cayley graphs, finding the exact solution in terms of dispersion relation.

  3. Reducing depressive symptoms after the Great East Japan Earthquake in older survivors through group exercise participation and regular walking: a prospective observational study

    Science.gov (United States)

    Tsuji, Taishi; Sasaki, Yuri; Matsuyama, Yusuke; Sato, Yukihiro; Aida, Jun; Kondo, Katsunori; Kawachi, Ichiro

    2017-01-01

    Objectives Survivors of the 2011 Great East Japan Earthquake have an increased risk of depressive symptoms. We sought to examine whether participation in group exercise and regular walking could mitigate the worsening of depressive symptoms among older survivors. Design Prospective observational study. Setting Our baseline survey was conducted in August 2010, ∼7 months prior to the Great East Japan Earthquake and tsunami, among people aged 65 or older residing in Iwanuma City, Japan, which suffered significant damage in the disaster. A 3-year follow-up survey was conducted in 2013. Participants 3567 older survivors responded to the questionnaires predisaster and postdisaster. Primary outcome measures Change in depressive symptoms was assessed using the 15-item Geriatric Depression Scale (GDS). Results From predisaster to postdisaster, the mean change in GDS score increased by 0.1 point (95% CI −0.003 to 0.207). During the same interval, the frequency of group exercise participation and daily walking time also increased by 1.9 days/year and 1.3 min/day, respectively. After adjusting for all covariates, including personal experiences of disaster, we found that increases in the frequency of group exercise participation (B=−0.139, β=−0.049, p=0.003) and daily walking time (B=−0.087, β=−0.034, p=0.054) were associated with lower GDS scores. Interactions between housing damage and changes in group exercise participation (B=0.103, β=0.034, p=0.063) and changes in walking habit (B=0.095, β=0.033, p=0.070) were marginally significant, meaning that the protective effects tended to be attenuated among survivors reporting more extensive housing damage. Conclusions Participation in group exercises or regular walking may mitigate the worsening of depressive symptoms among older survivors who have experienced natural disaster. PMID:28258173

  4. Random walks on three-strand braids and on related hyperbolic groups 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion; 02.50.-r Probability theory, stochastic processes, and statistics; 02.40.Ky Riemannian geometries;

    CERN Document Server

    Nechaev, S

    2003-01-01

    We investigate the statistical properties of random walks on the simplest nontrivial braid group B sub 3 , and on related hyperbolic groups. We provide a method using Cayley graphs of groups allowing us to compute explicitly the probability distribution of the basic statistical characteristics of random trajectories - the drift and the return probability. The action of the groups under consideration in the hyperbolic plane is investigated, and the distribution of a geometric invariant - the hyperbolic distance - is analysed. It is shown that a random walk on B sub 3 can be viewed as a 'magnetic random walk' on the group PSL(2, Z).

  5. Walking abnormalities

    Science.gov (United States)

    ... safety reasons, especially on uneven ground. See a physical therapist for exercise therapy and walking retraining. For a ... the right position for standing and walking. A physical therapist can supply these and provide exercise therapy, if ...

  6. The progene hypothesis: the nucleoprotein world and how life began.

    Science.gov (United States)

    Altstein, Anatoly D

    2015-11-26

    In this article, I review the results of studies on the origin of life distinct from the popular RNA world hypothesis. The alternate scenario postulates the origin of the first bimolecular genetic system (a polynucleotide gene and a polypeptide processive polymerase) with simultaneous replication and translation and includes the following key features: 1. The bimolecular genetic system emerges not from mononucleotides and monoamino acids, but from progenes, namely, trinucleotides aminoacylated on 3'-end by a non-random amino acid (NpNpNp ~ pX ~ Aa, where N--deoxyribo- or ribonucleoside, p--phosphate, X--a bifunctional agent, for example ribose, Aa--amino acid, ~ macroerge bond). Progenes are used as substrates for simultaneous synthesis of a polynucleotide and a polypeptide. Growth of the system is controlled by the growing polypeptide, and the bimolecular genetic system emerges as an extremely rare event. The first living being (virus-like organism protoviroid, Protoviroidum primum) arises and reproduces in prebiotic liposome-like structures using progenes. A population of protoviroids possessing the genetic system evolves in accordance with the Darwinian principle. Early evolution from protoviroid world to protocell world is shortly described. 2. The progene forming mechanism (NpNp + Np ~ pX ~ Aa) makes it possible to explain the emergence of the prebiotic physicochemical group genetic code, as well as the selection of organic compounds for the future genetic system from the racemic environment. 3. The protoviroid is reproduced on a progene basis via replicative transcription-translation (RTT, the first molecular genetic process) that is similar to its modern counterparts. Nothing is required for the emergence and reproduction of the protoviroid except for progenes and conditions for their formation. 4. The general scheme of early evolution is as follows: prebiotic world → protoviroid (nucleoprotein) world → protocell (DNA-RNA-protein) world → LUCA

  7. Quantum walks on Cayley graphs

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Acevedo, O [Laboratoire de Physique Theorique et Modelisation, Universite de Cergy-Pontoise, 2 Avenue Adolphe Chauvin 95302 Cergy Pontoise Cedex (France); Institut fuer Mathematik und Informatik, Ernst-Moritz-Arndt-Universitaet, Friedrich-Ludwig-Jahn Str.15a, 17487 Greifswald (Germany); Gobron, T [Laboratoire de Physique Theorique et Modelisation, Universite de Cergy-Pontoise, 2 Avenue Adolphe Chauvin 95302 Cergy Pontoise Cedex (France)

    2006-01-20

    We address the problem of the construction of quantum walks on Cayley graphs. Our main motivation is the relationship between quantum algorithms and quantum walks. In particular, we discuss the choice of the dimension of the local Hilbert space and consider various classes of graphs on which the structure of quantum walks may differ. We completely characterize quantum walks on free groups and present partial results on more general cases. Some examples are given including a family of quantum walks on the hypercube involving a Clifford algebra.

  8. Crowd of individuals walking in opposite directions. A toy model to study the segregation of the group into lanes of individuals moving in the same direction

    Science.gov (United States)

    Goldsztein, Guillermo H.

    2017-08-01

    Consider a corridor, street or bridge crowded with pedestrians walking in both directions. The individuals do not walk in a completely straight line. They adjust their path to avoid colliding with incoming pedestrians. As a result of these adjustments, the whole group sometimes end up split into lanes of individuals moving in the same direction. While this formation of lanes facilitates the flow and benefits the whole group, it is believed that results from the actions of the individuals acting only on their behalf, without considering others. This phenomenon is an example of self-organization. We analyze a simple model. We assume that individuals move around a two-lane circular track. All of them at the same speed. Half of them in one direction and the rest in the opposite direction. Each time two individuals collide, one of them moves to the other lane. The individual changing lanes is selected randomly. The system self-organizes. Eventually each lane is occupied with individuals moving in only one direction. We show that the time required for the system to self-organize is bounded by a linear function on the number of individuals. This toy model provides an example where global self-organization occurs even though each member of the group acts without considering the rest.

  9. Walking Problems

    Science.gov (United States)

    ... your legs or feet Movement disorders such as Parkinson's disease Diseases such as arthritis or multiple sclerosis Vision or balance problems Treatment of walking problems depends on the cause. Physical therapy, surgery, or mobility aids may help.

  10. Quantum walks on Cayley graphs

    CERN Document Server

    Acevedo, O L

    2006-01-01

    We address the problem of the construction of quantum walks on Cayley graphs. Our main motivation is the relationship between quantum algorithms and quantum walks. Thus we consider quantum walks on a general basis and try to classify them as a preliminary step in the construction of new algorithms that could be devised in this way. In particular, we discuss the choice of the dimension of the local Hilbert space, and consider various classes of graphs on which the structure of quantum walks may differ. We characterize completely the quantum walks on free groups and present partial results on more general cases. Examples are given among which a family of quantum walks on the hypercube involving a Clifford Algebra.

  11. Dynamic walking with Dribbel

    NARCIS (Netherlands)

    Dertien, Edwin Christian; Stramigioli, Stefano; Stramigioli, S.

    This paper describes the design and construction of Dribbel, a passivity-based walking robot. Dribbel has been designed and built at the Control Engineering group of the University of Twente. This paper focuses on the practical side: the design approach, construction, electronics, and software

  12. Dynamic walking with Dribbel

    NARCIS (Netherlands)

    Dertien, Edwin

    2006-01-01

    This paper describes the design and construction of Dribbel, a passivity-based walking robot. Dribbel has been designed and built at the Control Engineering group of the University of Twente. This paper focuses on the practical side: the design approach, construction, electronics, and software desig

  13. Walking around to grasp interaction

    DEFF Research Database (Denmark)

    Lykke, Marianne; Jantzen, Christian

    2013-01-01

    with the sound installations. The aim was to gain an understanding of the role of the in-teraction, if interaction makes a difference for the understanding of the sound art. 30 walking interviews were carried out at ZKM, Karlsruhe with a total of 57 museum guests, individuals or groups. During the walk......The paper presents experiences from a study using walk-alongs to provide insight into museum visitors’ experience with interactive features of sound art installations. The overall goal of the study was to learn about the participants’ opinions and feelings about the possibility of interaction...... knowledge of spa-tial conditions, e.g. noise, crowds, darkness provided a profound and shared un-derstanding of e.g. the visitors’ engagement in and dislike of the installations. Another finding concerns group walking that, compared to walking with a sin-gle person, generated a diversified discussion...

  14. Effectiveness of a Walking Group Intervention to Promote Physical Activity and Cardiovascular Health in Predominantly Non-Hispanic Black and Hispanic Urban Neighborhoods: Findings from the Walk Your Heart to Health Intervention

    Science.gov (United States)

    Schulz, Amy J.; Israel, Barbara A.; Mentz, Graciela B.; Bernal, Cristina; Caver, Deanna; DeMajo, Ricardo; Diaz, Gregoria; Gamboa, Cindy; Gaines, Causandra; Hoston, Bernadine; Opperman, Alisha; Reyes, Angela G.; Rowe, Zachary; Sand, Sharon L.; Woods, Sachiko

    2015-01-01

    Objectives: The purpose of this study was to evaluate the effectiveness of the "Walk Your Heart to Health" ("WYHH") intervention, one component of the multilevel Community Approaches to Cardiovascular Health: Pathways to Heart Health (CATCH:PATH) intervention designed to promote physical activity and reduce cardiovascular risk…

  15. Walking behavior in technicolored GUTs

    Energy Technology Data Exchange (ETDEWEB)

    Doff, A. [Universidade Tecnologica Federal do Parana-UTFPR-COMAT, Pato Branco, PR (Brazil)

    2009-03-15

    There exist two ways to obtain walk behavior: assuming a large number of technifermions in the fundamental representation of the technicolor (TC) gauge group, or a small number of technifermions, assuming that these fermions are in higher-dimensional representations of the TC group. We propose a scheme to obtain the walking behavior based on technicolored GUTs (TGUTs), where elementary scalars with the TC degree of freedom may remain in the theory after the GUT symmetry breaking. (orig.)

  16. The Effects of Dinner-to-Bed Time and Post-Dinner Walk on Gastric Cancer Across Different Age Groups: A Multicenter Case-Control Study in Southeast China.

    Science.gov (United States)

    Xu, Le; Zhang, Xi; Lu, Jun; Dai, Jia-Xi; Lin, Ren-Qin; Tian, Fang-Xi; Liang, Bing; Guo, Yi-Nan; Luo, Hui-Yu; Li, Ni; Fang, Dong-Ping; Zhao, Ruo-Hua; Huang, Chang-Ming

    2016-04-01

    Gastric cancer (GC) remains a major killer throughout the world. Despite the dramatic decrease in GC over the last century, its etiology has not yet been well characterized. This study investigated the possible independent and combined effects of the dinner-to-bed time and post-dinner walk on the risk for GC across different age groups. A population-based, case-control study was conducted in southeast China, including 452 patients with GC and 465 age-, race-, and gender-matched controls. A self-designed questionnaire was used to collect information on demographic characteristics, dinner-to-bed time, post-dinner walk, and other behavioral factors. Conditional logistic regression models were used to estimate the effects of the dinner-to-bed time and post-dinner walk as well as their joint effect on the risk for GC across different age groups. Individuals with dinner-to-bed time time was, the higher was the risk for GC (Ptrend time and post-dinner walk on GC risk was detected (AOR = 1.862, 95% CIs = 1.584-3.885, synergy index [SI] = 2.654, 95% CIs = 2.27-3.912). Participants with dinner-to-bed time times likely to suffer from GC (AOR = 7.401, 95% CIs = 4.523-13.16) than those with dinner-to-bed time ≥4 hours who took such walk. The risk of GC due to dinner-to-bed time time 55 years old.

  17. Effect of Body Composition on Walking Economy

    Directory of Open Access Journals (Sweden)

    Maciejczyk Marcin

    2016-12-01

    Full Text Available Purpose. The aim of the study was to evaluate walking economy and physiological responses at two walking speeds in males with similar absolute body mass but different body composition. Methods. The study involved 22 young men with similar absolute body mass, BMI, aerobic performance, calf and thigh circumference. The participants differed in body composition: body fat (HBF group and lean body mass (HLBM group. In the graded test, maximal oxygen uptake (VO2max and maximal heart rate were measured. Walking economy was evaluated during two walks performed at two different speeds (4.8 and 6.0 km ‧ h-1. Results. The VO2max was similar in both groups, as were the physiological responses during slow walking. The absolute oxygen uptake or oxygen uptake relative to body mass did not significantly differentiate the studied groups. The only indicator significantly differentiating the two groups was oxygen uptake relative to LBM. Conclusions. Body composition does not significantly affect walking economy at low speed, while during brisk walking, the economy is better in the HLBM vs. HBF group, provided that walking economy is presented as oxygen uptake relative to LBM. For this reason, we recommend this manner of oxygen uptake normalization in the evaluation of walking economy.

  18. Differences in walking pattern during 6-min walk test between patients with COPD and healthy subjects.

    Directory of Open Access Journals (Sweden)

    Janneke Annegarn

    Full Text Available BACKGROUND: To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT have not been performed in patients with chronic obstructive pulmonary disease (COPD. Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. METHODOLOGY/PRINCIPAL FINDINGS: 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD using multiple ordinary least squares (OLS regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%. CONCLUSIONS/SIGNIFICANCE: COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD.

  19. Ever Since the World Began: A Reading & Interview with Masha Tupitsyn

    Directory of Open Access Journals (Sweden)

    Masha Tupitsyn

    2013-07-01

    Full Text Available Writer and cultural critic Masha Tupitsyn is interviewed on her audio recording of her reading Ever Since This World Began, produced specially for this issue of continent. and adapted from her recently published Love Dog (Success and Failure out from Penny-Ante Editions.

  20. Man creation had began since the creation of the first biological ...

    African Journals Online (AJOL)

    Man creation had began since the creation of the first biological material very likely in ... of holy Qur'an verses related to the topic of man creation, the man creation had ... paper I will show that this conclusion is not in discordance with science.

  1. Community walking training program improves walking function and social participation in chronic stroke patients.

    Science.gov (United States)

    Kim, MinKyu; Cho, KiHun; Lee, WanHee

    2014-01-01

    Stroke patients live with balance and walking dysfunction. Walking is the most important factor for independent community activities. The purpose of this study was to investigate the effect of a community walking training program (CWTP) within the real environment on walking function and social participation in chronic stroke patients. Twenty-two stroke patients (13 male, 50.45 years old, post stroke duration 231.64 days) were randomly assigned to either the CWTP group or the control group. All subjects participated in the same standard rehabilitation program consisting of physical and occupational therapy for 60 min per day, five times a week, for four weeks. In addition, the CWTP group participated in CWTP for 30 min per day, five times a week, for four weeks. Walking function was assessed using the 10-m walk test (measurement for 10-meter walking speed), 6-min walk assessment (measurement of gait length for 6-minutes), and community gait assessment. Social participation was assessed using a social participation domain of stroke impact scale. In walking function, greater improvement was observed in the CWTP group compared with the control group (P participation improved more in the CWTP group compared with the control group (P participation in chronic stroke patients. Therefore, we suggest that CWTP within the real environment may be an effective method for improving walking function and social participation of chronic stroke patients when added to standard rehabilitation.

  2. The Walk Poem.

    Science.gov (United States)

    Padgett, Ron

    2000-01-01

    Discusses the long history of writing poems about a walk, noting many titles. Notes four basic types of walk poems and includes one by American poet Bill Zavatksy, called "Class Walk With Notebooks After Storm." Offers numerous brief ideas for both the writing and the form of walk poems. (SR)

  3. Walking, places and wellbeing

    NARCIS (Netherlands)

    Ettema, Dick; Smajic, Ifeta

    2015-01-01

    While there is a substantial body of research on the health implications of walking, the physical, emotional and social outcomes of walking have received limited attention. This paper explores the wellbeing effects of walking and how the walking environment fosters or hinders such wellbeing effects.

  4. Walking, places and wellbeing

    NARCIS (Netherlands)

    Ettema, Dick; Smajic, Ifeta

    2015-01-01

    While there is a substantial body of research on the health implications of walking, the physical, emotional and social outcomes of walking have received limited attention. This paper explores the wellbeing effects of walking and how the walking environment fosters or hinders such wellbeing effects.

  5. Using Focus Groups in the Consumer Research Phase of a Social Marketing Program to Promote Moderate-Intensity Physical Activity and Walking Trail Use in Sumter County, South Carolina

    Directory of Open Access Journals (Sweden)

    Ericka L. Burroughs, MA, MPH

    2005-12-01

    Full Text Available IntroductionThe use of social marketing approaches in public health practice is increasing. Using marketing concepts such as the “four Ps” (product, price, place, and promotion, social marketing borrows from the principles of commercial marketing but promotes beneficial health behaviors. Consumer research is used to segment the population and develop a strategy based on those marketing concepts. In a community-based participatory research study, 17 focus groups were used in consumer research to develop a social marketing program to promote walking and other moderate-intensity physical activities. MethodsTwo phases of focus groups were conducted. Phase 1 groups, which included both men and women, were asked to respond to questions that would guide the development of a social marketing program based on social marketing concepts. Phase 1 also determined the intervention’s target audience, which was irregularly active women aged 35 to 54. Phase 2 groups, composed of members of the target audience, were asked to further define the product and discuss specific promotion strategies. ResultsPhase 1 participants determined that the program product, or target behavior, should be walking. In addition, they identified price, place, and promotion strategies. Phase 2 participants determined that moderate-intensity physical activity is best promoted using the term exercise and offered suggestions for marketing walking, or exercise, to the target audience.ConclusionThere have been few published studies of social marketing campaigns to promote physical activity. In this study, focus groups were key to understanding the target audience in a way that would not have been accomplished with quantitative data alone. The group discussions generated important insights into values and motivations that affect consumers’ decisions to adopt a product or behavior. The focus group results guided the development of a social marketing program to promote physical

  6. Fire-Walking

    Science.gov (United States)

    Willey, David

    2010-01-01

    This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

  7. Fire-Walking

    Science.gov (United States)

    Willey, David

    2010-01-01

    This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

  8. Single and Dual Task Walking

    Directory of Open Access Journals (Sweden)

    Natalie de Bruin

    2010-01-01

    Full Text Available This study explored the viability and efficacy of integrating cadence-matched, salient music into a walking intervention for patients with Parkinson's disease (PD. Twenty-two people with PD were randomised to a control (CTRL, n=11 or experimental (MUSIC, n=11 group. MUSIC subjects walked with an individualised music playlist three times a week for the intervention period. Playlists were designed to meet subject's musical preferences. In addition, the tempo of the music closely matched (±10–15 bpm the subject's preferred cadence. CTRL subjects continued with their regular activities during the intervention. The effects of training accompanied by “walking songs” were evaluated using objective measures of gait score. The MUSIC group improved gait velocity, stride time, cadence, and motor symptom severity following the intervention. This is the first study to demonstrate that music listening can be safely implemented amongst PD patients during home exercise.

  9. Two- and 6-minute walk tests assess walking capability equally in neuromuscular diseases

    DEFF Research Database (Denmark)

    Andersen, Linda Kahr; Knak, Kirsten Lykke; Witting, Nanna;

    2016-01-01

    to participate on 2 test days, each consisting of 1 2MWT and 1 6MWT separated by a minimum 30-minute period of rest. The order of the walk tests was randomly assigned via sealed envelopes. A group of 38 healthy controls completed 1 6MWT. RESULTS: The mean walking distance for the 2MWT was 142.8 meters......OBJECTIVE: This methodologic study investigates if the 2-minute walk test (2MWT) can be a valid alternative to the 6-minute walk test (6MWT) to describe walking capability in patients with neuromuscular diseases. METHODS: Patients (n = 115) with different neuromuscular diseases were invited...... and for the 6MWT 405.3 meters. The distance walked in the 2MWT was highly correlated to the distance walked in the 6MWT (r = 0.99, p minute in the 6MWT, both among patients and healthy controls, which was not evident in the 2MWT...

  10. Effects of a Flexibility and Relaxation Programme, Walking, and Nordic Walking on Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    I. Reuter

    2011-01-01

    Full Text Available Symptoms of Parkinson's disease (PD progress despite optimized medical treatment. The present study investigated the effects of a flexibility and relaxation programme, walking, and Nordic walking (NW on walking speed, stride length, stride length variability, Parkinson-specific disability (UPDRS, and health-related quality of life (PDQ 39. 90 PD patients were randomly allocated to the 3 treatment groups. Patients participated in a 6-month study with 3 exercise sessions per week, each lasting 70 min. Assessment after completion of the training showed that pain was reduced in all groups, and balance and health-related quality of life were improved. Furthermore, walking, and Nordic walking improved stride length, gait variability, maximal walking speed, exercise capacity at submaximal level, and PD disease-specific disability on the UPDRS in addition. Nordic walking was superior to the flexibility and relaxation programme and walking in improving postural stability, stride length, gait pattern and gait variability. No significant injuries occurred during the training. All patients of the Nordic walking group continued Nordic walking after completing the study.

  11. Realisation of an energy efficient walking robot

    NARCIS (Netherlands)

    Dertien, Edwin; Oort, van Gijs; Stramigioli, Stefano

    2006-01-01

    In this video the walking robot ‘Dribbel’ is presented, which has been built at the Control Engineering group of the University of Twente, the Netherlands. This robot has been designed with a focus on minimal energy consumption, using a passive dynamic approach. It is a so-called four-legged 2D walk

  12. On alternating quantum walks

    Science.gov (United States)

    Rousseva, Jenia; Kovchegov, Yevgeniy

    2017-03-01

    We study an inhomogeneous quantum walk on a line that evolves according to alternating coins, each a rotation matrix. For the quantum walk with the coin alternating between clockwise and counterclockwise rotations by the same angle, we derive a closed form solution for the propagation of probabilities, and provide its asymptotic approximation via the method of stationary phase. Finally, we observe that for a x03c0;/4 angle, this alternating rotation walk will replicate the renown Hadamard walk.

  13. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    2002-01-01

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  14. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  15. Walking economy during cued versus non-cued treadmill walking in persons with Parkinson's disease.

    Science.gov (United States)

    Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

    2013-01-01

    Gait impairment is common in Parkinson's disease (PD) and may result in greater energy expenditure, poorer walking economy, and fatigue during activities of daily living. Auditory cueing is an effective technique to improve gait; but the effects on energy expenditure are unknown. To determine whether energy expenditure differs in individuals with PD compared with healthy controls and if auditory cueing improves walking economy in PD. Twenty participants (10 PD and 10 controls) came to the laboratory for three sessions. Participants performed two, 6-minute bouts of treadmill walking at two speeds (1.12 m·sec-1 and 0.67 m·sec-1). One session used cueing and the other without cueing. A metabolic cart measured energy expenditure and walking economy was calculated (energy expenditure/power). PD had worse walking economy and higher energy expenditure than control participants during cued and non-cued walking at the 0.67 m·sec-1 speed and during non-cued walking at the 1.12 m·sec-1. With auditory cueing, energy expenditure and walking economy worsened in both participant groups. People with PD use more energy and have worse walking economy than adults without PD. Walking economy declines further with auditory cuing in persons with PD.

  16. Walking performance: correlation between energy cost of walking and walking participation. new statistical approach concerning outcome measurement.

    Directory of Open Access Journals (Sweden)

    Marco Franceschini

    Full Text Available Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW, in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS. One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance.

  17. Why is understanding when Plate Tectonics began important for understanding Earth?

    Science.gov (United States)

    Korenaga, J.

    2015-12-01

    Almost all kinds of geological activities on Earth depend critically on the operation of plate tectonics, but did plate tectonics initiate right after the solidification of a putative magma ocean, or did it start much later, e.g., sometime during the Archean? This problem of the initiation of plate tectonics in the Earth history presents us a unique combination of observational and theoretical challenges. Finding geological evidence for the onset of plate tectonics is difficult because plate tectonics is a dynamic process that continuously destroys a remnant of the past. We therefore need to rely on more secondary traces, the interpretation of which often involves theoretical considerations. At the same time, it is still hard to predict, on a firm theoretical ground, when plate tectonics should have prevailed, because there is no consensus on why plate tectonics currently takes place on Earth. Knowing when plate tectonics began is one thing, and understanding why it did so is another. The initiation of plate tectonics is one of the last frontiers in earth science, which encourages a concerted effort from both geologists and geophysicists to identify key geological evidence and distinguish between competing theories of early Earth evolution. Such an endeavor is essential to arrive at a self-contained theory for the evolution of terrestrial planets.

  18. Genesis How the Universe Began According to Standard Model Particle Physics

    CERN Document Server

    Tipler, F J

    2001-01-01

    I show that the mutual consistency of the Bekenstein Bound, the Standard Model (SM) of particle physics, and general relativity implies that the universe began in a unique state. I solve the coupled EYM equations for this unique state, show how the horizon problem is solved, and how SM baryogenesis naturally results from the triangle anomoly. Since the SU(2) winding number state is thus non-zero, the universe is not in the QCD ground state, and this plausibly yields a (small) positive cosmological constant. Since the initial state is unique, it is necessarily homogeneous and isotropic, as required by the Bekenstein Bound. Wheeler-DeWitt quantization implies an $S^3$ cosmology must be very close to flat if the universe is to be classical today. I show that the spectrum of any classical gauge field (or interacting massless scalar field) in a FRW universe necessarily obeys the Wien displacement law and the corresponding quantized field the Planck distribution law with the reciprocal of the scale factor playing t...

  19. Effect of Body Composition on Walking Economy

    OpenAIRE

    Maciejczyk Marcin; Wiecek Magdalena; Szymura Jadwiga; Szygula Zbigniew

    2016-01-01

    Purpose. The aim of the study was to evaluate walking economy and physiological responses at two walking speeds in males with similar absolute body mass but different body composition. Methods. The study involved 22 young men with similar absolute body mass, BMI, aerobic performance, calf and thigh circumference. The participants differed in body composition: body fat (HBF group) and lean body mass (HLBM group). In the graded test, maximal oxygen uptake (VO2max) and maximal heart rate were me...

  20. Aerobic treadmill plus Bobath walking training improves walking in subacute stroke: a randomized controlled trial.

    Science.gov (United States)

    Eich, H-J; Mach, H; Werner, C; Hesse, S

    2004-09-01

    To evaluate the immediate and long-term effects of aerobic treadmill plus Bobath walking training in subacute stroke survivors compared with Bobath walking training alone. Randomized controlled trial. Rehabilitation unit. Fifty patients, first-time supratentorial stroke, stroke interval less than six weeks, Barthel Index (0-100) from 50 to 80, able to walk a minimum distance of 12 m with either intermittent help or stand-by while walking, cardiovascular stable, minimum 50 W in the bicycle ergometry, randomly allocated to two groups, A and B. Group A 30 min of treadmill training, harness secured and minimally supported according to patients' needs, and 30 min of physiotherapy, every workday for six weeks, speed and inclination of the treadmill were adjusted to achieve a heart rate of HR: (Hrmax-HRrest)*0.6+HRrest; in group B 60 min of daily physiotherapy for six weeks. Primary outcome variables were the absolute improvement of walking velocity (m/s) and capacity (m), secondary were gross motor function including walking ability (score out of 13) and walking quality (score out of 41), blindly assessed before and after the intervention, and at follow-up three months later. Patients tolerated the aerobic training well with no side-effects, significantly greater improvement of walking velocity and capacity both at study end (p =0.001 versus p =0.002) and at follow-up (p Bobath walking training in moderately affected stroke patients was better than Bobath walking training alone with respect to the improvement of walking velocity and capacity. The treatment approach is recommended in patients meeting the inclusion criteria. A multicentre trial should follow to strengthen the evidence.

  1. Walks on Weighted Networks

    Institute of Scientific and Technical Information of China (English)

    WU An-Cai; XU Xin-Jian; WU Zhi-Xi; WANG Ying-Hai

    2007-01-01

    We investigate the dynamics of random walks on weighted networks. Assuming that the edge weight and the node strength are used as local information by a random walker. Two kinds of walks, weight-dependent walk and strength-dependent walk, are studied. Exact expressions for stationary distribution and average return time are derived and confirmed by computer simulations. The distribution of average return time and the mean-square that a weight-dependent walker can arrive at a new territory more easily than a strength-dependent one.

  2. Effects of walking trainings on walking function among stroke survivors: a systematic review.

    Science.gov (United States)

    Ilunga Tshiswaka, Daudet; Bennett, Crystal; Franklin, Cheyanne

    2017-08-29

    Physical function is often compromised as a result of stroke event. Although interventions propose different strategies that seek to improve stroke survivors' physical function, a need remains to evaluate walking training studies aimed at improving such physical function. The aim of this review was to assess the available literature that highlights the impact of walking training on enhancing walking for stroke survivors. We performed a systematic literature review of online databases - Google Scholar, PubMed, CINHAL, Cochrane Library, Scopus, and EBSCO - with the following inclusion criteria: manuscript published from 2005 to 2016, written in English, with treatment and control groups, for walking training studies aimed at improving physical function among stroke survivors. Findings indicated that walking speed, walking distance, and gait speed were the most used outcome variables for measuring improved physical function among stroke survivors. Importantly, proposed interventions involved either overground or treadmill walking trainings, if not both. Preserved locomotor improvements were not noted in all interventions at follow-up. Some interventions that used walking treadmill training augmented by auditory stimulations reported significant improvements in physical function compared with overground walking training augmented by auditory stimulations. The imperative to improve physical function among stroke survivors with physical impairment is paramount, as it allows survivors to be socially, emotionally, and physically more independent. In general, we note an insufficiency of research on the interaction between physical function and socialization among stroke survivors.

  3. Sensorimotor-Conceptual Integration in Free Walking Enhances Divergent Thinking for Young and Older Adults

    Directory of Open Access Journals (Sweden)

    Chun-Yu Kuo

    2016-10-01

    Full Text Available Prior research has shown that free walking can enhance creative thinking. Nevertheless, it remains unclear whether bidirectional body-mind links are essential for the positive effect of free walking on creative thinking. Moreover, it is unknown whether the positive effect can be generalized to older adults. In Experiment 1, we replicated previous findings with two additional groups of young participants. Participants in the rectangular-walking condition walked along a rectangular path while generating unusual uses for chopsticks. Participants in the free-walking group walked freely as they wished, and participants in the free-generation condition generated unconstrained free paths while the participants in the random-experienced condition walked those paths. Only the free-walking group showed better performance in fluency, flexibility, and originality. In Experiment 2, two groups of older adults were randomly assigned to the free-walking and rectangular-walking conditions. The free-walking group showed better performance than the rectangular-walking group. Moreover, older adults in the free-walking group outperformed young adults in the rectangular-walking group in originality and performed comparably in fluency and flexibility. Bidirectional links between proprioceptive-motor kinematics and metaphorical abstract concepts can enhance divergent thinking for both young and older adults.

  4. More Adults Are Walking

    Centers for Disease Control (CDC) Podcasts

    2012-07-31

    This podcast is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.  Created: 7/31/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/7/2012.

  5. Momentum Dynamics of One Dimensional Quantum Walks

    CERN Document Server

    Fuss, I; Sherman, P J; Naguleswaran, S; Fuss, Ian; White, langord B.; Sherman, Peter J.; Naguleswaran, Sanjeev

    2006-01-01

    We derive the momentum space dynamic equations and state functions for one dimensional quantum walks by using linear systems and Lie group theory. The momentum space provides an analytic capability similar to that contributed by the z transform in discrete systems theory. The state functions at each time step are expressed as a simple sum of three Chebyshev polynomials. The functions provide an analytic expression for the development of the walks with time.

  6. Exploring scalar quantum walks on Cayley graphs

    CERN Document Server

    Acevedo, O L; Roland, J; Acevedo, Olga Lopez; Cerf, Nicolas J.

    2006-01-01

    A quantum walk, \\emph{i.e.}, the quantum evolution of a particle on a graph, is termed \\emph{scalar} if the internal space of the moving particle (often called the coin) has a dimension one. Here, we study the existence of scalar quantum walks on Cayley graphs, which are built from the generators of a group. After deriving a necessary condition on these generators for the existence of a scalar quantum walk, we present a general method to express the evolution operator of the walk, assuming homogeneity of the evolution. We use this necessary condition and the subsequent constructive method to investigate the existence of scalar quantum walks on Cayley graphs of various groups presented with two or three generators. In this restricted framework, we classify all groups -- in terms of relations between their generators -- that admit scalar quantum walks, and we also derive the form of the most general evolution operator. Finally, we point out some interesting special cases, and extend our study to a few examples ...

  7. Biomechanical analysis of rollator walking

    DEFF Research Database (Denmark)

    Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

    2006-01-01

    The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

  8. Walking, obesity and urban design in Chinese neighborhoods.

    Science.gov (United States)

    Alfonzo, Mariela; Guo, Zhan; Lin, Lin; Day, Kristen

    2014-12-01

    We examined the connections (1) between the design of the built environment and walking, (2) between the design of the built environment and obesity, and (3) between walking and obesity and income in urban settings in China. Six neighborhoods with different built environment characteristics, located in the Chinese cities of Shanghai and Hangzhou, were studied. Data on walking and other physical activity and obesity levels from 1070 residents were collected through a street intercept survey conducted in 2013. Built environment features of 527 street segments were documented using the Irvine-Minnesota Inventory-China (IMI-C) environmental audit. Data were analyzed using the State of Place™ Index. Walking rates, household income and Body Mass Index (BMI) were related; neighborhoods with a higher State of Place™ Index were associated with higher rates of walking. This study began to establish an evidence base for the association of built environment features with walking in the context of Chinese urban design. Findings confirmed that the associations between "walkable" built environment features and walking established in existing research in other countries, also held true in the case of Chinese neighborhoods. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Analysis and Modeling of Pedestrian Walking Behaviors Involving Individuals with Disabilities

    OpenAIRE

    Sharifi, Mohammad Sadra

    2016-01-01

    The objective of this dissertation was to study walking behaviors of pedestrian groups involving individuals with disabilities. To this end, large scale controlled walking experiments were conducted at Utah State University (USU) to examine walking behaviors in various walking facility types, such as passageway, right angle, oblique angle, queuing area, bottleneck, and stairs. Walking experiments were conducted over four days involving participants with and without disabilities. Automated vid...

  10. Quantum walks: a comprehensive review

    CERN Document Server

    Venegas-Andraca, Salvador E

    2012-01-01

    Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important resul...

  11. Begin the BEGAN (The Brown Educational Guide to the Analysis of Narrative) - a framework for enhancing educational impact of faculty feedback to students' reflective writing.

    Science.gov (United States)

    Reis, Shmuel P; Wald, Hedy S; Monroe, Alicia D; Borkan, Jeffrey M

    2010-08-01

    The study aim was the development of a method to further enhance the educational benefit of medical students' reflective writing. The setting is a Doctoring course at the Warren Alpert Medical School of Brown University, which includes reflective writing assignments, termed "field notes", combining students' reflective writing with ongoing individualized feedback from small group faculty. Three-year (2005-2008) iterative process with three stages of immersion, analysis, and revision that resulted in the analysis framework. An interdisciplinary team composed of the four authors with backgrounds in narrative medicine, qualitative research, psychology, and medical education analyzed 12 first and second year students' selected field notes in iterative cycles. In each cycle, consultations with small group faculty and content experts were conducted to further validate the emergent framework. This process culminated in the creation of the Brown Educational Guide to Analysis of Narrative (BEGAN) framework, a guide for crafting feedback to students' reflective writing, and the integration of the BEGAN framework into the faculty and student manuals for the Doctoring Course in 2008-2009. We propose the BEGAN framework as a useful innovative tool that can be incorporated in reflective writing curricula in the field of health professions education. It is tailored to support the educational impact of the course through additional scaffolding of student writing, and the robust process it delineates for crafting of faculty feedback. Providing systematic feedback to enhance reflective writing may represent the path forward in fostering professional development through reflection in health professions education. The BEGAN can be incorporated in reflective writing curricula in the field of health professions education. It is a springboard for the necessary next steps of development and research into the acquisition of reflective and narrative competence in the emerging professional

  12. Community walking in people with Parkinson's disease.

    Science.gov (United States)

    Lamont, Robyn M; Morris, Meg E; Woollacott, Marjorie H; Brauer, Sandra G

    2012-01-01

    People with Parkinson's disease often have walking difficulty, and this is likely to be exacerbated while walking in places in the community, where people are likely to face greater and more varied challenges. This study aims to understand the facilitators and the barriers to walking in the community perceived by people with Parkinson's disease. This qualitative study involved 5 focus groups (n = 34) of people with Parkinson's disease and their partners residing in metropolitan and rural regions in Queensland, Australia. Results found that people with PD reported to use internal personal strategies as facilitators to community walking, but identified primarily external factors, particularly the environmental factors as barriers. The adoption of strategies or the use of facilitators allows people with Parkinson's disease to cope so that participants often did not report disability.

  13. Walking - Sensing - Participation

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam; Browning, David

    Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider ...... set of experiential or ‘felt’ qualities of living with mobile technologies. Moving from reflections on the value of walking with people, the paper outlines some affordances of a smartphone application built to capture place experiences through walking....

  14. When Human Walking is a Random Walk

    Science.gov (United States)

    Hausdorff, J. M.

    1998-03-01

    The complex, hierarchical locomotor system normally does a remarkable job of controlling an inherently unstable, multi-joint system. Nevertheless, the stride interval --- the duration of a gait cycle --- fluctuates from one stride to the next, even under stationary conditions. We used random walk analysis to study the dynamical properties of these fluctuations under normal conditions and how they change with disease and aging. Random walk analysis of the stride-to-stride fluctuations of healthy, young adult men surprisingly reveals a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales (Hausdorff et al, J Appl Phsyiol, 1995). To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 hour at their usual pace, as well as at slower and faster speeds. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to a thousand strides at all three walking rates. In contrast, during metronomically-paced walking, these long-range correlations disappeared; variations in the stride interval were uncorrelated and non-fractal (Hausdorff et al, J Appl Phsyiol, 1996). To gain insight into the mechanism(s) responsible for this fractal property, we examined the effects of aging and neurological impairment. Using detrended fluctuation analysis (DFA), we computed α, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. α was significantly lower in healthy elderly subjects compared to young adults (p < .003) and in subjects with Huntington's disease, a neuro-degenerative disorder of the central nervous system, compared to disease-free controls (p < 0.005) (Hausdorff et al, J Appl Phsyiol, 1997). α was also significantly related to degree of functional impairment in subjects with Huntington's disease (r=0.78). Recently, we have observed that just as

  15. Crossover from random walk to self-avoiding walk

    Science.gov (United States)

    Rieger, Jens

    1988-11-01

    A one-dimensional n-step random walk on openZ1 which must not visit a vertex more than k times is studied via Monte Carlo methods. The dependences of the mean-square end-to-end distance of the walk and of the fraction of trapped walks on λ=(k-1)/n will be given for the range from λ=0 (self-avoiding walk) to λ=1 (unrestricted random walk). From the results it is conjectured that in the limit n-->∞ the walk obeys simple random walk statistics with respect to its static properties for all λ>0.

  16. Toe Walking in Children

    Science.gov (United States)

    ... may simply monitor your child's gait during regular office visits. If a physical problem is contributing to toe walking, treatment options may include: Physical therapy. Gentle stretching of the leg and foot muscles may improve ...

  17. The Act of Walking

    DEFF Research Database (Denmark)

    Vestergaard, Maria Quvang Harck; Olesen, Mette; Helmer, Pernille Falborg

    2014-01-01

    individuals in Denmark conduct and experience walking, and the ‘rationalities’ (Giddens 1984) that lie behind their choice of mobility. It provides insight into how different lifestyles perceive and act walking in their everyday life. Kaufmann (2002) describes how the individual mobility is influenced......’ of mobility (Jensen 2013:111) such as the urban environment, and the infrastructures. Walking has indeed also a ‘software dimension’ as an embodied performance that trigger the human senses (Jensen 2013) and which is closely related to the habitus and identity of the individual (Halprin 1963). The individual...... by individual strategies, values, perceptions and habits, and how appropriation of mobility is constructed through the internalization of standards and values. The act of walking could thus be understood as the result of dynamic internal negotiation of individual, everyday mobility strategies (Lassen 2005...

  18. Myoelectric walking mode classification for transtibial amputees.

    Science.gov (United States)

    Miller, Jason D; Beazer, Mahyo Seyedali; Hahn, Michael E

    2013-10-01

    Myoelectric control algorithms have the potential to detect an amputee's motion intent and allow the prosthetic to adapt to changes in walking mode. The development of a myoelectric walking mode classifier for transtibial amputees is outlined. Myoelectric signals from four muscles (tibialis anterior, medial gastrocnemius (MG), vastus lateralis, and biceps femoris) were recorded for five nonamputee subjects and five transtibial amputees over a variety of walking modes: level ground at three speeds, ramp ascent/descent, and stair ascent/descent. These signals were decomposed into relevant features (mean absolute value, variance, wavelength, number of slope sign changes, number of zero crossings) over three subwindows from the gait cycle and used to test the ability of classification algorithms for transtibial amputees using linear discriminant analysis (LDA) and support vector machine (SVM) classifiers. Detection of all seven walking modes had an accuracy of 97.9% for the amputee group and 94.7% for the nonamputee group. Misclassifications occurred most frequently between different walking speeds due to the similar nature of the gait pattern. Stair ascent/descent had the best classification accuracy with 99.8% for the amputee group and 100.0% for the nonamputee group. Stability of the developed classifier was explored using an electrode shift disturbance for each muscle. Shifting the electrode placement of the MG had the most pronounced effect on the classification accuracy for both samples. No increase in classification accuracy was observed when using SVM compared to LDA for the current dataset.

  19. Infant Social Development across the Transition from Crawling to Walking.

    Science.gov (United States)

    Walle, Eric A

    2016-01-01

    The onset of walking is a developmental transition that sets in motion a cascade of change across a range of domains, including social interactions and language learning. However, research on the unfolding of such change in the infant across this transition is limited. This investigation utilized a longitudinal design to examine the effect of walking acquisition on infant social development and parent perceptions of the infant to explore how changes in these factors relate with infant language development. Parents reported on infant social behaviors and their perception of the infant, as well as motor and language development, in 2-week intervals from 10.5 to 13 months of age. Mixed linear models revealed infant initiation of joint engagement (e.g., pointing, bringing objects to the parent) and following of the parent's joint engagement cues (e.g., point following, gaze following) increased as a function of infant walking experience, particularly between 2- and 4-weeks after the onset of walking, independent of age. Additionally, the parent's perception of the infant as an individual increased between 2- and 4-weeks after the infant began to walk. Finally, the unique relations of infant walking experience, following of social cues, and the parents' perception of the infant as an individual with infant language development were examined. Infant following of joint engagement behaviors and parent perception of the infant as an individual were related to receptive, but not productive, vocabulary size. Additionally, infant walking experience remained a significant predictor of infant receptive and productive language. These findings provide insight on important factors that change as the infant begins to walk. Future research utilizing more direct assessment of these factors is described, as well as general patterning of developmental change across the transition from crawling to walking.

  20. Age-related differences in walking stability.

    Science.gov (United States)

    Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C

    2003-03-01

    a large proportion of falls in older people occur when walking; however the mechanisms underlying impaired balance during gait are poorly understood. to evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing affects postural responses to challenging walking conditions. temporo-spatial gait parameters and variables derived from acceleration signals were recorded in 30 young people aged 22-39 years (mean 29.0, SD 4.3), and 30 older people with a low risk of falling aged 75-85 years (mean 79.0, SD 3.0) while walking on a level and an irregular walking surface. Subjects also underwent tests of vision, sensation, strength, reaction time and balance. older subjects exhibited a more conservative gait pattern, characterised by reduced velocity, shorter step length and increased step timing variability. These differences were particularly pronounced when walking on the irregular surface. The magnitude of accelerations at the head and pelvis were generally smaller in older subjects; however the smoothness of the acceleration signals did not differ between the two groups. Older subjects performed worse on tests of vision, peripheral sensation, strength, reaction time and balance. the adoption of a more conservative basic gait pattern by older people with a low risk of falling reduces the magnitude of accelerations experienced by the head and pelvis when walking, which is likely to be a compensatory strategy to maintain balance in the presence of age-related deficits in physiological function, particularly reduced lower limb strength.

  1. Adaptive Levy walks in foraging fallow deer.

    Directory of Open Access Journals (Sweden)

    Stefano Focardi

    Full Text Available BACKGROUND: Lévy flights are random walks, the step lengths of which come from probability distributions with heavy power-law tails, such that clusters of short steps are connected by rare long steps. Lévy walks maximise search efficiency of mobile foragers. Recently, several studies raised some concerns about the reliability of the statistical analysis used in previous analyses. Further, it is unclear whether Lévy walks represent adaptive strategies or emergent properties determined by the interaction between foragers and resource distribution. Thus two fundamental questions still need to be addressed: the presence of Lévy walks in the wild and whether or not they represent a form of adaptive behaviour. METHODOLOGY/PRINCIPAL FINDINGS: We studied 235 paths of solitary and clustered (i.e. foraging in group fallow deer (Dama dama, exploiting the same pasture. We used maximum likelihood estimation for discriminating between a power-tailed distribution and the exponential alternative and rank/frequency plots to discriminate between Lévy walks and composite Brownian walks. We showed that solitary deer perform Lévy searches, while clustered animals did not adopt that strategy. CONCLUSION/SIGNIFICANCE: Our demonstration of the presence of Lévy walks is, at our knowledge, the first available which adopts up-to-date statistical methodologies in a terrestrial mammal. Comparing solitary and clustered deer, we concluded that the Lévy walks of solitary deer represent an adaptation maximising encounter rates with forage resources and not an epiphenomenon induced by a peculiar food distribution.

  2. Biomechanical analysis of rollator walking

    Directory of Open Access Journals (Sweden)

    Nielsen Linda H

    2006-01-01

    Full Text Available Abstract Background The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects. Methods The walking pattern during walking with and without rollator was analyzed using a three-dimensional inverse dynamics method. Sagittal joint dynamics and kinematics of the ankle, knee and hip were calculated. In addition, hip joint dynamics and kinematics in the frontal plane were calculated. Seven healthy women participated in the study. Results The hip was more flexed while the knee and ankle joints were less flexed/dorsiflexed during rollator walking. The ROM of the ankle and knee joints was reduced during rollator-walking. Rollator-walking caused a reduction in the knee extensor moment by 50% when compared to normal walking. The ankle plantarflexor and hip abductor moments were smaller when walking with a rollator. In contrast, the angular impulse of the hip extensors was significantly increased during rollator-walking. Conclusion Walking with a rollator unloaded the ankle and especially the knee extensors, increased the hip flexion and thus the contribution of hip extensors to produce movement. Thus, rollator walking did not result in an overall unloading of the muscles and joints of the lower extremities. However, the long-term effect of rollator walking is unknown and further investigation in this field is needed.

  3. Neuromechanical adaptations during a robotic powered exoskeleton assisted walking session.

    Science.gov (United States)

    Ramanujam, Arvind; Cirnigliaro, Christopher M; Garbarini, Erica; Asselin, Pierre; Pilkar, Rakesh; Forrest, Gail F

    2017-04-20

    To evaluate gait parameters and neuromuscular profiles of exoskeleton-assisted walking under Max Assist condition during a single-session for; (i) able bodied (AB) individuals walking assisted with (EXO) and without (non-EXO) a powered exoskeleton, (ii) non-ambulatory SCI individuals walking assisted with a powered exoskeleton. Single-session. Motion analysis laboratory. Four AB individuals and four individuals with SCI. Powered lower extremity exoskeleton. Temporal-spatial parameters, kinematics, walking velocity and electromyography data. AB individuals in exoskeleton showed greater stance time and a significant reduction in walking velocity (P exoskeleton movements, they walked with an increased velocity and lowered stance time to resemble that of slow walking. For SCI individuals, mean percent stance time was higher and walking velocity was lower compared to all AB walking conditions (P exoskeleton and moreover with voluntary control there is a greater temporal-spatial response of the lower limbs. Also, there are neuromuscular phasic adaptions for both AB and SCI groups while walking in the exoskeleton that are inconsistent to non-EXO gait muscle activation.

  4. Ascending evacuation in long stairways: Physical exertion, walking speed and behaviour

    OpenAIRE

    Ronchi, Enrico; Norén, Johan; Delin, Mattias; Kuklane, Kalev; Halder, Amitava; Arias, Silvia; Fridolf, Karl

    2015-01-01

    This is the final report of the project “Ascending evacuation in long stairways: Physical exertion, walking speed and behaviour”. This project investigated the effects of fatigue on walking speeds, physiological performance and behaviours in case of long ascending evacuation. The report includes a literature review on, at the time when the project began, existing material on ascending evacuation on long stairs and escalators. Experimental research was conducted and the results are presented i...

  5. SEARCH THE RELATIONSHIP SATISFACTION AND THE ELDERLY WALK

    Directory of Open Access Journals (Sweden)

    Siamak Takash

    2011-01-01

    Full Text Available Study the relationship between walking and elderly satisfaction is assessed. Transparency to therelationship between the effects of walking and training methods were used separately.Accidentally an experimental group versus a control group investigated are. Experimental groupa walk older free and as a group; but the other group; two walk in a gym was. Participants 12elderly people between the ages of 47 to 74 years for a two-month walk volunteered. resultsvery active physical activity (energy to the least active (tired; drowsy disgruntle very active(angry to enable good-natured little (slowly; with dignity was used. In terms of assessment(EA and (TA is EA has been shown 5;10;15. EA than in all minutes walking time. But at thetime of EA 10 to break down Trust. During walking; the happiness and excitement duringwalking; freshness and vitality; and its surface is more than the main axis is higher. Happinessand excitement rapidly rising compared to walking group (2 under rest and more than 15minutes. It is recommended that one should exercise and hardly have to push.

  6. Unitary equivalence of quantum walks

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Sandeep K., E-mail: sandeep.goyal@ucalgary.ca [School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, 4000 Durban (South Africa); Konrad, Thomas [School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, 4000 Durban (South Africa); National Institute for Theoretical Physics (NITheP), KwaZulu-Natal (South Africa); Diósi, Lajos [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, H-1525 Budapest 114, P.O.B. 49 (Hungary)

    2015-01-23

    Highlights: • We have found unitary equivalent classes in coined quantum walks. • A single parameter family of coin operators is sufficient to realize all simple one-dimensional quantum walks. • Electric quantum walks are unitarily equivalent to time dependent quantum walks. - Abstract: A simple coined quantum walk in one dimension can be characterized by a SU(2) operator with three parameters which represents the coin toss. However, different such coin toss operators lead to equivalent dynamics of the quantum walker. In this manuscript we present the unitary equivalence classes of quantum walks and show that all the nonequivalent quantum walks can be distinguished by a single parameter. Moreover, we argue that the electric quantum walks are equivalent to quantum walks with time dependent coin toss operator.

  7. How nonimaging optics began

    Science.gov (United States)

    Winston, Roland

    2016-09-01

    Classical optics was traditionally the mapping of point sources by lenses, mirrors and occasionally holograms , i.e. making an image. The subject has had many famous scientists associated with it; Fermat, Huygens, Descartes, Hamilton just to name a few. By the mid 20th Century it was a well-developed field as exemplified by such luminaries as Walter T. Welford, Emil Wolf and many others. The theory of aberrations which addresses the imperfections of the mapping codified the state of the art. Then arose the need to collect energy, not just images. To the author's knowledge it can be traced back to WWII Germany with collection of infra-red radiation (the work by D. E. Williamson, was not published until 1952). The radiation collector, a simple right-circular cone, was a harbinger of things to come.

  8. Tomorrow Began Yesterday

    Directory of Open Access Journals (Sweden)

    Konstantin Lidin

    2014-01-01

    Full Text Available The phenomenon of the sixtiers was prepared by the previous historical period. The period after the World War II comprises a fundamental change of the world order – from a multipolar world to a confrontation of two superpowers and two ideological systems, and, at the same time, formation of a complex of international organizations on a global scale. In this context, the Soviet architecture made a sharp turn from Stalin’s Empire style to an extreme ascetism – the continuation of constructivism of the early XXth century. The Irkutsk architectural school, unlike the main flow of the 1960s, developed the style of Neo-Brutalism. The article draws parallels between Neo-Brutalism of the Irkutsk school and “a severe style” of the Soviet pictorial art of the same period.

  9. Effects of a novel walking training program with postural correction and visual feedback on walking function in patients with post-stroke hemiparesis.

    Science.gov (United States)

    Won, Sang Hee; Kim, Jae Cheol; Oh, Duck-Won

    2015-08-01

    [Purpose] This study aimed to elucidate the effects of a novel walking training program with postural correction and visual feedback on walking function in patients with post-stroke hemiparesis. [Subjects] Sixteen subjects were randomly allocated to either the experimental group (EG) or the control group (CG), with eight subjects in each. [Methods] EG and CG subjects performed a 30-min treadmill walking training exercise twice daily for 2 weeks. EG subjects also underwent postural correction using elastic bands and received visual feedback during walking. The 10-m walk test was performed, and gait parameters were measured using a gait analysis system. [Results] All parameters showed significant main effects for the group factor and time-by-group interactions. Significant main effects for the time factor were found in the stride length and stance phase ratios. [Conclusion] The novel walking training program with postural correction and visual feedback may improve walking function in patients with post-stroke hemiparesis.

  10. Walking With Meaning

    Directory of Open Access Journals (Sweden)

    Jennifer McDuff

    2015-09-01

    Full Text Available Physical activity is beneficial for people with dementia, but little research explores subjective experiences of physical activity in this population. Interpretive description guided the analysis of 26 interviews conducted with 12 people with dementia. Three themes described the subjective meaning of everyday physical activity: Participants were attracted to activity because it improved physical well-being, provided social connections, gave opportunity to be in nature, and provided structure and focus; participants experienced impediments to activity because of physical discomfort, environmental factors, lack of enthusiasm, and memory loss; and participants made adjustments by choosing walking over other activities and by being active with others. Results show that physical activity remains important for people with dementia, although they encounter barriers. They may prefer walking with others as a form of activity. Findings could influence how nurses conceptualize wandering and suggest that walking programs could be well received by people with dementia.

  11. Biomechanical conditions of walking

    CERN Document Server

    Fan, Y F; Luo, L P; Li, Z Y; Han, S Y; Lv, C S; Zhang, B

    2015-01-01

    The development of rehabilitation training program for lower limb injury does not usually include gait pattern design. This paper introduced a gait pattern design by using equations (conditions of walking). Following the requirements of reducing force to the injured side to avoid further injury, we developed a lower limb gait pattern to shorten the stride length so as to reduce walking speed, to delay the stance phase of the uninjured side and to reduce step length of the uninjured side. This gait pattern was then verified by the practice of a rehabilitation training of an Achilles tendon rupture patient, whose two-year rehabilitation training (with 24 tests) has proven that this pattern worked as intended. This indicates that rehabilitation training program for lower limb injury can rest on biomechanical conditions of walking based on experimental evidence.

  12. Bouncing and walking droplets

    Science.gov (United States)

    Molacek, Jan; Bush, John

    2012-11-01

    Motivated by the hydrodynamic quantum analogue system of Yves Couder, we examine the dynamics of silicone oil drops bouncing on a vertically vibrating liquid bath. We report regime diagrams indicating the dependence of the vertical drop motion on the system parameters. A logarithmic spring model for the interface is developed, and provides new rationale for the regime diagrams. We further examine the spatio-temporal evolution of the standing waves created on the bath surface by repeated drop impacts. Measurement of the tangential coefficient of restitution of drops bouncing on a quiescent bath enables us to accurately determine all the major forces acting on the drop during flight and impact. By combining the horizontal and vertical dynamics, we thus develop a model for the walking drops that enables us to rationalize both the extent of the walking regime and the walking speeds. The model predictions compare favorably with experimental data in the parameter range explored.

  13. Ways of Walking

    DEFF Research Database (Denmark)

    Eslambolchilar, Parisa; Bødker, Mads; Chamberlain, Alan

    2016-01-01

    It seems logical to argue that mobile computing technologies are intended for use "on-the-go." However, on closer inspection, the use of mobile technologies pose a number of challenges for users who are mobile, particularly moving around on foot. In engaging with such mobile technologies...... and their envisaged development, we argue that interaction designers must increasingly consider a multitude of perspectives that relate to walking in order to frame design problems appropriately. In this paper, we consider a number of perspectives on walking, and we discuss how these may inspire the design of mobile...... technologies. Drawing on insights from non-representational theory, we develop a partial vocabulary with which to engage with qualities of pedestrian mobility, and we outline how taking more mindful approaches to walking may enrich and inform the design space of handheld technologies....

  14. Does walking exercise improve bone mineral density of young ...

    African Journals Online (AJOL)

    Does walking exercise improve bone mineral density of young obese and ... min walking between 50-75% of maximal age adjusted heart rate, 3 days per ... Also no significant change was observed in blood samples in either group (p>0.05).

  15. From Walking to Running

    Science.gov (United States)

    Rummel, Juergen; Blum, Yvonne; Seyfarth, Andre

    The implementation of bipedal gaits in legged robots is still a challenge in state-of-the-art engineering. Human gaits could be realized by imitating human leg dynamics where a spring-like leg behavior is found as represented in the bipedal spring-mass model. In this study we explore the gap between walking and running by investigating periodic gait patterns. We found an almost continuous morphing of gait patterns between walking and running. The technical feasibility of this transition is, however, restricted by the duration of swing phase. In practice, this requires an abrupt gait transition between both gaits, while a change of speed is not necessary.

  16. The Act of Walking

    DEFF Research Database (Denmark)

    Vestergaard, Maria Quvang Harck; Olesen, Mette; Helmer, Pernille Falborg

    2014-01-01

    ’ of mobility (Jensen 2013:111) such as the urban environment, and the infrastructures. Walking has indeed also a ‘software dimension’ as an embodied performance that trigger the human senses (Jensen 2013) and which is closely related to the habitus and identity of the individual (Halprin 1963). The individual...... the individuals evaluate, interpret and act (Bourdieu 1984), and how this affects their choice to walk. Therefore it could be questioned if whether an assessment of the physical environment is sufficient to identify all the factors that influence the individual perception of ‘walkability’, or if other influencing...

  17. Walking for data

    DEFF Research Database (Denmark)

    Bødker, Mads; Browning, David; Meinhardt, Nina Dam

    We suggest that ‘walking’ in ethnographic work sensitizes researchers to a particular means of making sense of place. Following a brief conceptual exposition, we present our research tool iMaCam) that supports capturing and representing activities such as walking.......We suggest that ‘walking’ in ethnographic work sensitizes researchers to a particular means of making sense of place. Following a brief conceptual exposition, we present our research tool iMaCam) that supports capturing and representing activities such as walking....

  18. Aperiodic Quantum Random Walks

    CERN Document Server

    Ribeiro, P; Mosseri, R; Ribeiro, Pedro; Milman, Perola; Mosseri, Remy

    2004-01-01

    We generalize the quantum random walk protocol for a particle in a one-dimensional chain, by using several types of biased quantum coins, arranged in aperiodic sequences, in a manner that leads to a rich variety of possible wave function evolutions. Quasiperiodic sequences, following the Fibonacci prescription, are of particular interest, leading to a sub-ballistic wavefunction spreading. In contrast, random sequences leads to diffusive spreading, similar to the classical random walk behaviour. We also describe how to experimentally implement these aperiodic sequences.

  19. DIFFERENCE IN THE NORDIC WALKING AND WALKING ON MORPHOLOGICAL CHARACTERISTICS OF WOMEN

    Directory of Open Access Journals (Sweden)

    Nebojša Čokorilo

    2013-07-01

    Full Text Available Walking is one of the few physical activities that suit most people: do not burden the body as intensely as other activities, injuries are rare, and it is necessary to determine the conditions for its exercise. Unlike normal walking, when the upper body is relatively passive, Nordic Walking activates more muscles of the back and arms. Using poles while walking reduces the load on the lower extremities, especially the hip joints, knees and ankles. Elderly people use sticks provides greater stability as it increases the support surface and thus reduces the risk of falls and injury, dangerous occurrence of fractures. The aim of the research is the evaluation of the effects of two models of walking and determine the differences in the results on the morphological characteristics of elderly women. The study comprised 87 individuals, females, aged between 50 and 60 years, territories, municipalities Novi Sad. In the first experimental group'' E1'' was regular and 30 females and their data are taken into consideration. The second experimental group'' E2'' had 27 trainees have been regular. Those in the control group were 30th The measurement of skin fold and circumference measurements and procedures were performed in accordance with IBP - player. The experimental program lasted three months. Differences between individual groups in each variable were calculated using LSD - post hoc test. Were found statistically significant differences between experimental groups and between the two experimental.

  20. Comparison of the Effect of Lateral and Backward Walking Training on Walking Function in Patients with Poststroke Hemiplegia: A Pilot Randomized Controlled Trial.

    Science.gov (United States)

    Kim, Chang-Yong; Lee, Jung-Sun; Kim, Hyeong-Dong

    2017-02-01

    The purposes of the present study were to compare the effects of backward and lateral walking training and to identify whether additional backward or lateral walking training would be more effective in increasing the walking function of poststroke patients. Fifty-one subjects with hemiplegic stroke were randomly allocated to 3 groups, each containing 17 subjects: the control group, the backward walking training group, and the lateral walking training group. The walking abilities of each group were assessed using a 10-m walk test and the GAITRite system for spatiotemporal gait. The results show that there were significantly greater posttest increases in gait velocity (F = -12.09, P = 0.02) and stride length (F = -11.50, P = 0.02), decreases in the values of the 10-m walk test (F = -7.10, P = 0.03) (P training group compared with those in the other 2 groups. These findings demonstrate that asymmetric gait patterns in poststroke patients could be improved by receiving additional lateral walking training therapy rather than backward walking training. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) understand the potential benefits of backward walking (BW) and lateral walking (LW) training on improving muscle strength and gait; (2) appreciate the potential value of backward and lateral walking gait training in the treatment of hemiplegic stroke patients; and (3) appropriately incorporate backward and lateral walking gait training into the treatment plan of hemiplegic stroke patients. Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit

  1. Walking for data

    DEFF Research Database (Denmark)

    Bødker, Mads; Browning, David; Meinhardt, Nina Dam

    We suggest that ‘walking’ in ethnographic work sensitizes researchers to a particular means of making sense of place. Following a brief conceptual exposition, we present our research tool iMaCam) that supports capturing and representing activities such as walking....

  2. Walking. Sensing. Participation

    DEFF Research Database (Denmark)

    Bødker, Mads

    2014-01-01

    This paper uses three meditations to contemplate walking, sensing and participation as three ways with which we can extend the notion of ‘experiential computing’ proposed by Yoo (2010). By using the form of meditations, loosely associated concepts that are part introspective and part ‘causative’, i...

  3. Walking Advisement: Program Description.

    Science.gov (United States)

    Byram Hills School District, Armonk, NY.

    The Walking Advisement program at Crittenden Middle School in Armonk, New York was started during the 1984-1985 school year. It was based on the work of Alfred Arth, a middle school specialist at the University of Wyoming. Essentially, the program attempts to expand the guidance function of the school by bringing faculty and students together to…

  4. Walking along water

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2014-01-01

    Steep slopes, white peaks and deep valleys make up the Andes. As phenomenologists of landscape have told us, different people have different landscapes. By moving across the terrain, walking along, we might get a sense of how this has been carved out by the movement of wind and water, tectonics...

  5. The walking robot project

    Science.gov (United States)

    Williams, P.; Sagraniching, E.; Bennett, M.; Singh, R.

    1991-01-01

    A walking robot was designed, analyzed, and tested as an intelligent, mobile, and a terrain adaptive system. The robot's design was an application of existing technologies. The design of the six legs modified and combines well understood mechanisms and was optimized for performance, flexibility, and simplicity. The body design incorporated two tripods for walking stability and ease of turning. The electrical hardware design used modularity and distributed processing to drive the motors. The software design used feedback to coordinate the system and simple keystrokes to give commands. The walking machine can be easily adapted to hostile environments such as high radiation zones and alien terrain. The primary goal of the leg design was to create a leg capable of supporting a robot's body and electrical hardware while walking or performing desired tasks, namely those required for planetary exploration. The leg designers intent was to study the maximum amount of flexibility and maneuverability achievable by the simplest and lightest leg design. The main constraints for the leg design were leg kinematics, ease of assembly, degrees of freedom, number of motors, overall size, and weight.

  6. Deterministic Walks with Choice

    Energy Technology Data Exchange (ETDEWEB)

    Beeler, Katy E.; Berenhaut, Kenneth S.; Cooper, Joshua N.; Hunter, Meagan N.; Barr, Peter S.

    2014-01-10

    This paper studies deterministic movement over toroidal grids, integrating local information, bounded memory and choice at individual nodes. The research is motivated by recent work on deterministic random walks, and applications in multi-agent systems. Several results regarding passing tokens through toroidal grids are discussed, as well as some open questions.

  7. Walking along water

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2014-01-01

    Steep slopes, white peaks and deep valleys make up the Andes. As phenomenologists of landscape have told us, different people have different landscapes. By moving across the terrain, walking along, we might get a sense of how this has been carved out by the movement of wind and water, tectonics...

  8. Walking and Sensing Mobile Lives

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam

    In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk.......In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk....

  9. Snakes and perturbed random walks

    CERN Document Server

    Basak, Gopal

    2011-01-01

    In this paper we study some properties of random walks perturbed at extrema, which are generalizations of the walks considered e.g., in Davis (1999). This process can also be viewed as a version of {\\em excited random walk}, studied recently by many authors. We obtain a few properties related to the range of the process with infinite memory. We also prove the Strong law, Central Limit Theorem, and the criterion for the recurrence of the perturbed walk with finite memory.

  10. k-Walk-Regular Digraphs

    Institute of Scientific and Technical Information of China (English)

    Wen LIU; Jing LIN

    2011-01-01

    In this paper,we define a class of strongly connected digraph,called the k-walk-regular digraph,study some properties of it,provide its some algebraic characterization and point out that the O-walk-regular digraph is the same as the walk-regular digraph discussed BY Liu and Lin in 2010 and the D-walk-regular digraph is identical with the weakly distance-regular digraph defined by Comellas et al in 2004.

  11. Walking and Sensing Mobile Lives

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam

    In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk.......In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk....

  12. Realisation of an energy efficient walking robot

    NARCIS (Netherlands)

    Dertien, Edwin Christian; van Oort, Gijs; Stramigioli, Stefano

    2006-01-01

    In this video the walking robot ‘Dribbel’ is presented, which has been built at the Control Engineering group of the University of Twente, the Netherlands. This robot has been designed with a focus on minimal energy consumption, using a passive dynamic approach. It is a so-called four-legged 2D

  13. The variability problem of normal human walking

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Alkjær, Tine

    2012-01-01

    a group of normal subjects and to test whether or not the expected differences would prove to be statistically significant. Fifteen healthy male subjects were recorded on video while they walked across two force platforms. Ten kinematic and kinetic parameters were selected and input to a statistical...

  14. A comparison of the Endurance Shuttle Walk test and the Six Minute Walk test for assessment of exercise capacity in older people.

    Science.gov (United States)

    Witham, Miles D; Sugden, Jacqui A; Sumukadas, Deepa; Dryburgh, Moira; McMurdo, Marion E T

    2012-04-01

    The six minute walk test is widely used to measure aerobic exercise capacity in older people, but lack responsiveness to change. We aimed to compare the reliability, responsiveness and completion rates of the six minute walk with a new test of aerobic exercise capacity - the endurance shuttle walk test. Two groups were studied: 18 patients from a Medicine for the Elderly Day Hospital (study 1) receiving physiotherapy, and 15 community dwelling older people (study 2) receiving caffeine or placebo in a crossover study, followed by a weekly exercise programme. Six minute walk test and endurance shuttle walk test were performed at baseline and after interventions. Intraclass correlation coefficients were calculated for reliability, and Cohen's effect sizes were calculated to characterize responsiveness. 6/18 of patients in study 1 completed the baseline shuttle walk successfully. For those completing baseline and week one shuttle walk, similar intraclass correlation coefficients were seen (shuttle walk 0.97; six minute walk 0.90). In study 2, all attendees completed baseline and follow-up shuttle walk. 7/15 managed the maximum shuttle walk time at baseline. Effect sizes for caffeine intervention (0.29 for six minute walk, 0.01 for shuttle walk) and for exercise intervention (0.15 for six minute walk, 0.24 for shuttle walk) were similarly low for both tests. The endurance shuttle walk is no more responsive to change than the six minute walk in older people, is limited by ceiling effects, and cannot be performed successfully by very frail older people.

  15. Treadmill training improves overground walking economy in Parkinson's disease: a randomized, controlled pilot study.

    Science.gov (United States)

    Fernández-Del-Olmo, Miguel Angel; Sanchez, Jose Andres; Bello, Olalla; Lopez-Alonso, Virginia; Márquez, Gonzalo; Morenilla, Luis; Castro, Xabier; Giraldez, Manolo; Santos-García, Diego

    2014-01-01

    Gait disturbances are one of the principal and most incapacitating symptoms of Parkinson's disease (PD). In addition, walking economy is impaired in PD patients and could contribute to excess fatigue in this population. An important number of studies have shown that treadmill training can improve kinematic parameters in PD patients. However, the effects of treadmill and overground walking on the walking economy remain unknown. The goal of this study was to explore the walking economy changes in response to a treadmill and an overground training program, as well as the differences in the walking economy during treadmill and overground walking. Twenty-two mild PD patients were randomly assigned to a treadmill or overground training group. The training program consisted of 5 weeks (3 sessions/week). We evaluated the energy expenditure of overground walking, before and after each of the training programs. The energy expenditure of treadmill walking (before the program) was also evaluated. The treadmill, but not the overground training program, lead to an improvement in the walking economy (the rate of oxygen consumed per distance during overground walking at a preferred speed) in PD patients. In addition, walking on a treadmill required more energy expenditure compared with overground walking at the same speed. This study provides evidence that in mild PD patients, treadmill training is more beneficial compared with that of walking overground, leading to a greater improvement in the walking economy. This finding is of clinical importance for the therapeutic administration of exercise in PD.

  16. Impact of a short walking exercise on gait kinematics in children with cerebral palsy who walk in a crouch gait.

    Science.gov (United States)

    Parent, Audrey; Raison, Maxime; Pouliot-Laforte, Annie; Marois, Pierre; Maltais, Désirée B; Ballaz, Laurent

    2016-05-01

    Crouch gait results in an increase of the joint stress due to an excessive knee flexion. Daily walking exercises, even when performed at a self-selected speed, may result in a decrease of the extensor muscle strength which could lead to a more severe crouch gait pattern. The aim of this study was to assess the impact of a short walking exercise on gait kinematics in children with cerebral palsy who walk with a crouch gait. Seven children with cerebral palsy who walk with a crouch gait were asked to walk for 6min at a self-selected speed. The spatio-temporal and kinematic measures, as well as the center of mass position were compared before and after the exercise. There was no significant difference between walking speed before and after the walking exercise. Knee flexion and the maximal ankle dorsiflexion increased after the walking exercise. The vertical position of the center of mass decreased. No significant difference was found at the hip. Children with cerebral palsy who walk with a crouch gait were more crouched after a 6-min walking exercise performed at their self-selected speed. These gait modifications could be due to fatigue of the extensor muscle groups. This study highlighted that a short walking exercise, corresponding to daily mobility, results in gait pattern modifications. Since therapies in children with cerebral palsy aim to improve motor function in everyday life situations, it could be relevant to evaluate gait adaptation after a few minutes of walking exercise. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Virological failure of staggered and simultaneous treatment interruption in HIV patients who began Efavirenz-based regimens after allergic reactions to nevirapine

    Directory of Open Access Journals (Sweden)

    Siripassorn Krittaecho

    2013-01-01

    Full Text Available Abstract Objective The objective of this work was to study the virological outcomes associated with two different types of treatment interruption strategies in patients with allergic reactions to nevirapine (NVP. We compared the virological outcomes of (1 HIV-1-infected patients who discontinued an initial NVP-based regimen because of cutaneous allergic reactions to NVP; different types of interruption strategies were used, and second-line regimen was based on efavirenz (EFV; and (2 HIV-1-infected patients who began an EFV-based regimen as a first-line therapy (controls. Methods This retrospective cohort included patients who began an EFV-based regimen, between January 2002 and December 2008, as either an initial regimen or as a subsequent regimen after resolving a cutaneous allergic reaction against an initial NVP-based regimen. The study ended in March 2010. The primary outcome was virological failure, which was defined as either (a two consecutive plasma HIV-1 RNA levels >400 copies/mL or (b a plasma HIV-1 RNA level >1,000 copies/mL plus any genotypic resistance mutation. Results A total of 559 patients were stratified into three groups: (a Simultaneous Interruption, in which the subjects simultaneously discontinued all the drugs in an NVP-based regimen following an allergic reaction (n=161; (b Staggered Interruption, in which the subjects discontinued NVP treatment while continuing nucleoside reverse transcriptase inhibitor (NRTI backbone therapy for a median of 7 days (n=82; and (c Control, in which the subjects were naïve to antiretroviral therapy (n=316. The overall median follow-up time was 43 months. Incidence of virological failure in Simultaneous Interruption was 12.9 cases per 1,000 person-years, which trended toward being higher than the incidences in Staggered Interruption (5.4 and Control (6.6. However, differences were not statistically significant. Conclusions Among the patients who had an acute allergic reaction to first

  18. Reliability of the 6-min walk test after total knee arthroplasty

    DEFF Research Database (Denmark)

    Jakobsen, Thomas Linding; Kehlet, Henrik; Bandholm, Thomas

    2013-01-01

    PURPOSE: The 6-min walk test is a simple clinical outcome measure, which has been used frequently to assess functional performance in many different patient groups, including patients with total knee arthroplasty (TKA). The 6-min walk test measures the maximal distance a subject is able to walk...

  19. Why Understanding When and How Plate Tectonics Began Is Essential for a Robust Theory of the Earth

    Science.gov (United States)

    Stern, R. J.; Gerya, T.

    2014-12-01

    Understanding when and how Plate Tectonics (PT) began and what came before has profound implications for understanding the Earth because the transition to PT from the previous tectonic regime - some variant of deformable lid tectonics (DLT)- resulted in faster cooling and enhanced recycling of surface materials to depth. The transition to PT also would have impacted ocean chemistry, climate and life evolution. There is no consensus about when PT began on Earth; estimates range from >4.2 Ga to ~0.85 Ga. Three pillars of a robust Theory of the Earth illustrate the importance of answering this question: (1) the solid Earth volatile cycle; (2) the Urey ratio; and (3) the kimberlite enigma. For (1), it is now clear that subduction injects more H2O (and probably CO2) into Earth's mantle- where it is stored - than is released to the surface by igneous activity. Presumably the volatile flux from the surface into the mantle was lower during DLT episodes, although delamination and Rayleigh-Taylor drippings would have sent some. Constraining PT H2O and CO2 fluxes requires knowing when PT began and interior soaking accelerated. Regarding (2), estimating Earth's Urey ratio (Ur; heat production/heat loss) evolution requires avoiding the "thermal catastrophe" implying that if Earth has been cooling off as fast as presently (Ur ~0.2) then it must have been totally molten 1-2 Ga; a transition from DLT (high Ur) to PT (low Ur) may resolve the paradox. Finally (3), why are the vast majority of kimberlites of Phaneozoic age? Is it because erosion has removed the evidence or because sufficient H2O-CO2 rich fluids that drive such eruptions have only been delivered below cratonic lithosphere since deep subduction associated with PT began? Determining when did PT start, what was Earth's DLT-regime before this, and how did the transition occur will require the insights of the entire geoscientific community, providing a worthy set of 21st Century geoscientific research priorities.

  20. [Walking abnormalities in children].

    Science.gov (United States)

    Segawa, Masaya

    2010-11-01

    Walking is a spontaneous movement termed locomotion that is promoted by activation of antigravity muscles by serotonergic (5HT) neurons. Development of antigravity activity follows 3 developmental epochs of the sleep-wake (S-W) cycle and is modulated by particular 5HT neurons in each epoch. Activation of antigravity activities occurs in the first epoch (around the age of 3 to 4 months) as restriction of atonia in rapid eye movement (REM) stage and development of circadian S-W cycle. These activities strengthen in the second epoch, with modulation of day-time sleep and induction of crawling around the age of 8 months and induction of walking by 1 year. Around the age of 1 year 6 months, absence of guarded walking and interlimb cordination is observed along with modulation of day-time sleep to once in the afternoon. Bipedal walking in upright position occurs in the third epoch, with development of a biphasic S-W cycle by the age of 4-5 years. Patients with infantile autism (IA), Rett syndrome (RTT), or Tourette syndrome (TS) show failure in the development of the first, second, or third epoch, respectively. Patients with IA fail to develop interlimb coordination; those with RTT, crawling and walking; and those with TS, walking in upright posture. Basic pathophysiology underlying these condition is failure in restricting atonia in REM stage; this induces dysfunction of the pedunculopontine nucleus and consequently dys- or hypofunction of the dopamine (DA) neurons. DA hypofunction in the developing brain, associated with compensatory upward regulation of the DA receptors causes psychobehavioral disorders in infancy (IA), failure in synaptogenesis in the frontal cortex and functional development of the motor and associate cortexes in late infancy through the basal ganglia (RTT), and failure in functional development of the prefrontal cortex through the basal ganglia (TS). Further, locomotion failure in early childhood causes failure in development of functional

  1. Fractional random walk lattice dynamics

    CERN Document Server

    Michelitsch, Thomas; Riascos, Alejandro Perez; Nowakowski, Andrzeij; Nicolleau, Franck

    2016-01-01

    We analyze time-discrete and continuous `fractional' random walks on undirected regular networks with special focus on cubic periodic lattices in $n=1,2,3,..$ dimensions.The fractional random walk dynamics is governed by a master equation involving {\\it fractional powers of Laplacian matrices $L^{\\frac{\\alpha}{2}}$}where $\\alpha=2$ recovers the normal walk.First we demonstrate thatthe interval $0\\textless{}\\alpha\\leq 2$ is admissible for the fractional random walk. We derive analytical expressions for fractional transition matrix and closely related the average return probabilities. We further obtain thefundamental matrix $Z^{(\\alpha)}$, and the mean relaxation time (Kemeny constant) for the fractional random walk.The representation for the fundamental matrix $Z^{(\\alpha)}$ relates fractional random walks with normal random walks.We show that the fractional transition matrix elements exihibit for large cubic $n$-dimensional lattices a power law decay of an $n$-dimensional infinite spaceRiesz fractional deriva...

  2. Covering walks in graphs

    CERN Document Server

    Fujie, Futaba

    2014-01-01

    Covering Walks  in Graphs is aimed at researchers and graduate students in the graph theory community and provides a comprehensive treatment on measures of two well studied graphical properties, namely Hamiltonicity and traversability in graphs. This text looks into the famous Kӧnigsberg Bridge Problem, the Chinese Postman Problem, the Icosian Game and the Traveling Salesman Problem as well as well-known mathematicians who were involved in these problems. The concepts of different spanning walks with examples and present classical results on Hamiltonian numbers and upper Hamiltonian numbers of graphs are described; in some cases, the authors provide proofs of these results to illustrate the beauty and complexity of this area of research. Two new concepts of traceable numbers of graphs and traceable numbers of vertices of a graph which were inspired by and closely related to Hamiltonian numbers are introduced. Results are illustrated on these two concepts and the relationship between traceable concepts and...

  3. Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

    Directory of Open Access Journals (Sweden)

    Matthew R Holdgate

    Full Text Available Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33 and Asian (n = 23 elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

  4. Attentional costs of visually guided walking: effects of age, executive function and stepping-task demands.

    Science.gov (United States)

    Mazaheri, Masood; Roerdink, Melvyn; Bood, Robert Jan; Duysens, Jacques; Beek, Peter J; Peper, C Lieke E

    2014-01-01

    During walking, attention needs to be flexibly allocated to deal with varying environmental constraints. This ability may be affected by aging and lower overall executive function. The present study examined the influence of aging and executive function on the attentional costs of visually guided walking under different task demands. Three groups, young adults (n=15) and elderly adults with higher (n=16) and lower (n=10) executive function, walked on a treadmill in three conditions: uncued walking and walking with regular and irregular patterns of visual stepping targets projected onto the belt. Attentional costs were assessed using a secondary probe reaction time task and corrected by subtracting baseline single-task reaction time, yielding an estimate of the additional attentional costs of each walking condition. We found that uncued walking was more attentionally demanding for elderly than for young participants. In young participants, the attentional costs increased significantly from uncued to regularly cued to irregularly cued walking, whereas for the higher executive function group, attentional costs only increased significantly from regularly cued to irregularly cued walking. For the group with lower executive function, no significant differences were observed. The observed decreased flexibility of elderly, especially those with lower executive function, to allocate additional attentional resources to more challenging walking conditions may be attributed to the already increased attentional costs of uncued walking, presumably required for visuomotor and/or balance control of walking.

  5. The effect of treadmill exercise on gait efficiency during overground walking in adults with cerebral palsy.

    Science.gov (United States)

    Kim, On-Yoo; Shin, Yoon-Kyum; Yoon, Young Kwon; Ko, Eu Jeong; Cho, Sung-Rae

    2015-02-01

    To investigate the effect of treadmill walking exercise as a treatment method to improve gait efficiency in adults with cerebral palsy (CP) and to determine gait efficiency during overground walking after the treadmill walking exercise. Fourteen adults with CP were recruited in the experimental group of treadmill walking exercise. A control group of 7 adults with CP who attended conventional physical therapy were also recruited. The treadmill walking exercise protocol consisted of 3-5 training sessions per week for 1-2 months (total 20 sessions). Gait distance, velocity, VO2, VCO2, O2 rate (mL/kg·min), and O2 cost (mL/kg·m) were assessed at the beginning and at the end of the treadmill walking exercise. The parameters were measured by KB1-C oximeter. After the treadmill walking exercise, gait distance during overground walking up to 6 minutes significantly increased from 151.29±91.79 to 193.93±79.01 m, and gait velocity increased from 28.09±14.29 to 33.49±12.69 m/min (pexercise. On the other hand, gait velocity and O2 cost during overground walking were not significantly changed in the control group. Treadmill walking exercise improved the gait efficiency by decreased energy expenditure during overground walking in adults with CP. Therefore, treadmill walking exercise can be an important method for gait training in adults with CP who have higher energy expenditure.

  6. Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal

    2007-01-01

    I report on our construction and analysis of the effective low energy Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of the effective Lagrangian are constrained by imposing modified Weinberg sum rules and by imposing a value for the S parameter estimated from the under...... the underlying Technicolor theory. The constrained effective Lagrangian allows for an inverted vector vs. axial-vector mass spectrum in a large part of the parameter space....

  7. Nordic Walking Classes

    CERN Multimedia

    Fitness Club

    2015-01-01

    Four classes of one hour each are held on Tuesdays. RDV barracks parking at Entrance A, 10 minutes before class time. Spring Course 2015: 05.05/12.05/19.05/26.05 Prices 40 CHF per session + 10 CHF club membership 5 CHF/hour pole rental Check out our schedule and enroll at: https://espace.cern.ch/club-fitness/Lists/Nordic%20Walking/NewForm.aspx? Hope to see you among us! fitness.club@cern.ch

  8. Walking with springs

    Science.gov (United States)

    Sugar, Thomas G.; Hollander, Kevin W.; Hitt, Joseph K.

    2011-04-01

    Developing bionic ankles poses great challenges due to the large moment, power, and energy that are required at the ankle. Researchers have added springs in series with a motor to reduce the peak power and energy requirements of a robotic ankle. We developed a "robotic tendon" that reduces the peak power by altering the required motor speed. By changing the required speed, the spring acts as a "load variable transmission." If a simple motor/gearbox solution is used, one walking step would require 38.8J and a peak motor power of 257 W. Using an optimized robotic tendon, the energy required is 21.2 J and the peak motor power is reduced to 96.6 W. We show that adding a passive spring in parallel with the robotic tendon reduces peak loads but the power and energy increase. Adding a passive spring in series with the robotic tendon reduces the energy requirements. We have built a prosthetic ankle SPARKy, Spring Ankle with Regenerative Kinetics, that allows a user to walk forwards, backwards, ascend and descend stairs, walk up and down slopes as well as jog.

  9. An exploration of impaired walking dynamics and fatigue in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Burschka Janina M

    2012-12-01

    Full Text Available Abstract Background Physical disability in multiple sclerosis (MS is frequently characterized by impaired ambulation. Although walking tests have been successfully employed to assess walking ability in MS patients, data analytic procedures have predominantly relied on result-oriented parameters (e.g. total distance covered during a given amount of time, whereas process-oriented, dynamic walking patterns have mostly been ignored. This is striking, since healthy individuals have been observed to display a stereotypical U-shaped pattern of walking speed during timed walking, characterized by relatively high speed during the initial phase, subsequent slowing and final acceleration. Objective of the current study was to test the utility of the 6 min Walk (6MW and the 12 min Walk (12MW for revealing putatively abnormal temporal dynamic features of walking in MS. Methods A group of 37 MS patients was divided into subgroups with regard to their level of disability analyzed with the Expanded Disability Status Scale (EDSS; Mild MS Group, n = 20, EDSS 0 – 3.5; Moderate MS Group, n = 17, EDSS 4 – 5. Subsequently, both groups were compared to age-matched healthy controls (n = 25 on both tests with regard to result-oriented characteristics (mean walking speed, as well as dynamic features (mean decline in walking speed, degree of observed U-shape. Results Both MS groups showed a significantly lower mean walking speed than healthy controls, independent of test duration. Compared to controls, the Moderate MS Group also slowed down more rapidly throughout both tests. The same pronounced decline in walking speed was observed for the Mild MS Group in case of the 12MW. Additionally, for both MS groups an attenuated U-shaped velocity pattern was observed relative to controls in the 6MW. Patients' subjective fatigue scores were more strongly correlated with the decline in walking speed than with the common parameter of mean walking speed in the 6MW

  10. A formative evaluation of a family-based walking intervention-Furness Families Walk4Life

    Directory of Open Access Journals (Sweden)

    Bull Fiona

    2011-08-01

    Full Text Available Abstract Background The family unit may be an important mechanism for increasing physical activity levels, yet little is known about what types of family-based interventions are effective. This study involved a formative evaluation of a 12 week intervention to encourage walking as a family based activity. The intervention consisted of several key elements including led walks and tailored resources, as well as remote support provided via the telephone. The project aimed to explore factors associated with successful delivery of the programme and to identify areas of improvement for future implementation. Methods A total of nine interviews were undertaken with programme staff who were involved in either the set up or delivery of the intervention. In addition, four interviews and two focus groups were undertaken with participants to explore their experiences of the programme. The analysis involved both deductive and inductive reasoning. Results In total, 114 people participated in the programme, which included 36 adults, 10 adolescents and 68 children (≤ 10 years of age. Adult participants reported several barriers to walking including concerns over their children's behaviour and their ability to maintain 'control' of their children. Walking in a group with other families gave parents confidence to go out walking with their children and provided a valuable opportunity for social interaction for parents and children alike. The most successful walks incorporated specific destinations and an activity to undertake upon reaching the destination. Incorporating other activities along the way also helped to keep the children engaged. Conclusions The results of this study have highlighted the important contribution that formative research can make in informing and refining a programme to increase appropriateness and effectiveness. The study has helped to highlight the key characteristics associated with delivering a successful walking intervention to young

  11. Multicomponent Fitness Training Improves Walking Economy in Older Adults.

    Science.gov (United States)

    Valenti, Giulio; Bonomi, Alberto Giovanni; Westerterp, Klaas Roelof

    2016-07-01

    Walking economy declines with increasing age, possibly leading to mobility limitation in older adults. Multicomponent fitness training could delay the decline in walking economy. This study aimed to determine the effect of multicomponent fitness training on walking economy in older adults. Participants were untrained adults, age 50 to 83 yr (N = 26, 10 males, age = 63 ± 6 yr, BMI = 25.6 ± 2.1 kg·m, mean ± SD). A control group was also recruited (N = 16, 9 males, age = 66 ± 10 yr, BMI = 25.4 ± 3.0 kg·m), matching the intervention group for age, weight, body composition, and fitness. The intervention group followed a multicomponent fitness program of 1 h, twice per week during 1 yr. The control group did not take part in any physical training. Fat-free mass, walking economy, and maximal oxygen uptake (V˙O2max) were measured in both groups before and after the year. Walking economy was measured with indirect calorimetry as the lowest energy needed to displace 1 kg of body mass for 1 m while walking on a treadmill. The data were compared between the two groups with repeated-measures ANOVA. Thirty-two subjects completed all measurements. There was an interaction between the effects of time and group on V˙O2max (P economy (P economy. Thus, training programs could delay mobility limitation with increasing age.

  12. Building the repertoire of measures of walking in Rett syndrome

    DEFF Research Database (Denmark)

    Stahlhut, Michelle; Downs, Jenny; Leonard, Helen;

    2017-01-01

    BACKGROUND: The repertoire of measures of walking in Rett syndrome is limited. This study aimed to determine measurement properties of a modified two-minute walk test (2MWT) and a modified Rett syndrome-specific functional mobility scale (FMS-RS) in Rett syndrome. METHODS: Forty-two girls and women...... with Rett syndrome (median 18.4 years, range 2.4-60.9 years) were assessed for clinical severity, gross motor skills, and mobility. To measure walking capacity, 27 of this group completed a 2MWT twice on two different assessment days. To assess walking performance, the FMS-RS was administered to the total......) and the Rett syndrome-specific functional mobility scale (FMS-RS). The 2MWT and FMS-RS offer detailed information of the capacity and performance of walking, respectively, in girls and women with RTT....

  13. THE RESEARCH OF TIME-HISTORY RESPONSE ANALYSIS OF FOOTBRIDGE VIBRATION BASED ON STIMULATION OF GROUP WALKING%人行天桥振动时程分析方法的研究

    Institute of Scientific and Technical Information of China (English)

    蔡静敏; 陈学伟

    2009-01-01

    Occupant comfort when footbridge systems are subjected to crowd-induced vibrations has become an important index to evaluate serviceability of structures. Control of static deflections stipulated in current code cannot sufficiently represent the serviceability requirements of long-span systems. Harmonic vibration analysis procedure is introduced by foreign code requirements to deal with floor vibrations, with the restriction to those with regular shapes and simple boundary conditions. This paper proposes a time-history analysis program based on load induced by human activities and the stimulation of group walking. Footbridge systems with special boundary condition, span and damping are analyzed by time-history method. Compared with the results of crowd-induced load experiment, the analytical results confirmed the accuracy of this analysis procedure in representing the characteristic of crowd-induced .floor vibrations, which is applicable for evaluation of floor systems with arbitrary shape and boundary condition.%人行天桥在人群走动引起的振动作用下的舒适度成为评价人行天桥适用性的重要指标.现行规范给出的静力挠度控制并不能充分体现大跨度结构的正常使用要求.国外规程对楼板振动问题采用稳态响应分析方法,但该方法局限于平面规则、边界条件简单楼板,不适用复杂的楼板体系.根据人群的行走规律,对人群走动进行仿真的基础上编制了人行荷载时程生成程序,并采用人群行走致使天桥板面振动的时程分析方法,对特定边界条件、跨度及阻尼的天桥结构进行时程分析.最后将计算结果与人行荷载试验进行对比.表明该时程分析方法能较精确反映楼板人致振动的特性,并适用于任意形状及边界条件的楼板舒适度的评估.

  14. Renormalization of the unitary evolution equation for coined quantum walks

    Science.gov (United States)

    Boettcher, Stefan; Li, Shanshan; Portugal, Renato

    2017-03-01

    We consider discrete-time evolution equations in which the stochastic operator of a classical random walk is replaced by a unitary operator. Such a problem has gained much attention as a framework for coined quantum walks that are essential for attaining the Grover limit for quantum search algorithms in physically realizable, low-dimensional geometries. In particular, we analyze the exact real-space renormalization group (RG) procedure recently introduced to study the scaling of quantum walks on fractal networks. While this procedure, when implemented numerically, was able to provide some deep insights into the relation between classical and quantum walks, its analytic basis has remained obscure. Our discussion here is laying the groundwork for a rigorous implementation of the RG for this important class of transport and algorithmic problems, although some instances remain unresolved. Specifically, we find that the RG fixed-point analysis of the classical walk, which typically focuses on the dominant Jacobian eigenvalue {λ1} , with walk dimension dw\\text{RW}={{log}2}{λ1} , needs to be extended to include the subdominant eigenvalue {λ2} , such that the dimension of the quantum walk obtains dw\\text{QW}={{log}2}\\sqrt{{λ1}{λ2}} . With that extension, we obtain analytically previously conjectured results for dw\\text{QW} of Grover walks on all but one of the fractal networks that have been considered.

  15. Nordic Walking improves daily physical activities in COPD: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Breyer Marie-Kathrin

    2010-08-01

    Full Text Available Abstract Background In patients with COPD progressive dyspnoea leads to a sedentary lifestyle. To date, no studies exist investigating the effects of Nordic Walking in patients with COPD. Therefore, the aim was to determine the feasibility of Nordic Walking in COPD patients at different disease stages. Furthermore we aimed to determine the short- and long-term effects of Nordic Walking on COPD patients' daily physical activity pattern as well as on patients exercise capacity. Methods Sixty COPD patients were randomised to either Nordic Walking or to a control group. Patients of the Nordic Walking group (n = 30; age: 62 ± 9 years; FEV1: 48 ± 19% predicted underwent a three-month outdoor Nordic Walking exercise program consisting of one hour walking at 75% of their initial maximum heart rate three times per week, whereas controls had no exercise intervention. Primary endpoint: daily physical activities (measured by a validated tri-axial accelerometer; secondary endpoint: functional exercise capacity (measured by the six-minute walking distance; 6MWD. Assessment time points in both groups: baseline, after three, six and nine months. Results After three month training period, in the Nordic Walking group time spent walking and standing as well as intensity of walking increased (Δ walking time: +14.9 ± 1.9 min/day; Δ standing time: +129 ± 26 min/day; Δ movement intensity: +0.40 ± 0.14 m/s2 while time spent sitting decreased (Δ sitting time: -128 ± 15 min/day compared to baseline (all: p Conclusions Nordic Walking is a feasible, simple and effective physical training modality in COPD. In addition, Nordic Walking has proven to positively impact the daily physical activity pattern of COPD patients under short- and long-term observation. Clinical trial registration Nordic Walking improves daily physical activities in COPD: a randomised controlled trial - ISRCTN31525632

  16. Individual, employment and psychosocial factors influencing walking to work: Implications for intervention design.

    Science.gov (United States)

    Adams, Emma J; Esliger, Dale W; Taylor, Ian M; Sherar, Lauren B

    2017-01-01

    Promoting walking for the journey to and from work (commuter walking) is a potential strategy for increasing physical activity. Understanding the factors influencing commuter walking is important for identifying target groups and designing effective interventions. This study aimed to examine individual, employment-related and psychosocial factors associated with commuter walking and to discuss the implications for targeting and future design of interventions. 1,544 employees completed a baseline survey as part of the 'Walking Works' intervention project (33.4% male; 36.3% aged logistic regression was used to examine the associations of individual (age, ethnic group, educational qualifications, number of children <16 and car ownership), employment-related (distance lived from work, free car parking at work, working hours, working pattern and occupation) and psychosocial factors (perceived behavioural control, intention, social norms and social support from work colleagues) with commuter walking. Almost half of respondents (n = 587, 49%) were classified as commuter walkers. Those who were aged <30 years, did not have a car, had no free car parking at work, were confident of including some walking or intended to walk to or from work on a regular basis, and had support from colleagues for walking were more likely to be commuter walkers. Those who perceived they lived too far away from work to walk, thought walking was less convenient than using a car for commuting, did not have time to walk, needed a car for work or had always travelled the same way were less likely to be commuter walkers. A number of individual, employment-related and psychosocial factors were associated with commuter walking. Target groups for interventions to promote walking to and from work may include those in older age groups and those who own or have access to a car. Multi-level interventions targeting individual level behaviour change, social support within the workplace and organisational

  17. Effect of concurrent walking and interlocutor distance on conversational speech intensity and rate in Parkinson's disease.

    Science.gov (United States)

    McCaig, Cassandra M; Adams, Scott G; Dykstra, Allyson D; Jog, Mandar

    2016-01-01

    Previous studies have demonstrated a negative effect of concurrent walking and talking on gait in Parkinson's disease (PD) but there is limited information about the effect of concurrent walking on speech production. The present study examined the effect of sitting, standing, and three concurrent walking tasks (slow, normal, fast) on conversational speech intensity and speech rate in fifteen individuals with hypophonia related to idiopathic Parkinson's disease (PD) and fourteen age-equivalent controls. Interlocuter (talker-to-talker) distance effects and walking speed were also examined. Concurrent walking was found to produce a significant increase in speech intensity, relative to standing and sitting, in both the control and PD groups. Faster walking produced significantly greater speech intensity than slower walking. Concurrent walking had no effect on speech rate. Concurrent walking and talking produced significant reductions in walking speed in both the control and PD groups. In general, the results of the present study indicate that concurrent walking tasks and the speed of concurrent walking can have a significant positive effect on conversational speech intensity. These positive, "energizing" effects need to be given consideration in future attempts to develop a comprehensive model of speech intensity regulation and they may have important implications for the development of new evaluation and treatment procedures for individuals with hypophonia related to PD.

  18. Neuromuscular determinants of maximum walking speed in well-functioning older adults.

    Science.gov (United States)

    Clark, David J; Manini, Todd M; Fielding, Roger A; Patten, Carolynn

    2013-03-01

    Maximum walking speed may offer an advantage over usual walking speed for clinical assessment of age-related declines in mobility function that are due to neuromuscular impairment. The objective of this study was to determine the extent to which maximum walking speed is affected by neuromuscular function of the lower extremities in older adults. We recruited two groups of healthy, well functioning older adults who differed primarily on maximum walking speed. We hypothesized that individuals with slower maximum walking speed would exhibit reduced lower extremity muscle size and impaired plantarflexion force production and neuromuscular activation during a rapid contraction of the triceps surae muscle group (soleus (SO) and gastrocnemius (MG)). All participants were required to have usual 10-meter walking speed of >1.0m/s. If the difference between usual and maximum 10m walking speed was 0.6m/s, the individual was assigned to the "Faster" group (n=12). Peak rate of force development (RFD) and rate of neuromuscular activation (rate of EMG rise) of the triceps surae muscle group were assessed during a rapid plantarflexion movement. Muscle cross sectional area of the right triceps surae, quadriceps and hamstrings muscle groups was determined by magnetic resonance imaging. Across participants, the difference between usual and maximal walking speed was predominantly dictated by maximum walking speed (r=.85). We therefore report maximum walking speed (1.76 and 2.17m/s in Slower and Faster, ptriceps surae (p=.44), quadriceps (p=.76) and hamstrings (p=.98). MG rate of EMG rise was positively associated with RFD and maximum 10m walking speed, but not the usual 10m walking speed. These findings support the conclusion that maximum walking speed is limited by impaired neuromuscular force and activation of the triceps surae muscle group. Future research should further evaluate the utility of maximum walking speed for use in clinical assessment to detect and monitor age

  19. Quantum walks on general graphs

    CERN Document Server

    Kendon, V

    2003-01-01

    A scheme for a discrete time quantum walk on a general graph of N vertices with undirected edges is given, and compared with the continuous time quantum walk on a general graph introduced by Farhi and Gutmann [PRA 58 915 (1998)]. Both walks are contrasted with the examples of quantum walks in the literature treating graphs of fixed, small (< log N) degree. This illustrates the way in which extra information about the graph allows more efficient algorithms to be designed. To obtain a quantum speed up over classical for comparable resources it is necessary to code the position space of the quantum walk into a qubit register (or equivalent). The role of the oracle is also discussed and an efficient gate sequence is presented for implementing a discrete quantum walk given one copy of a quantum state encoding the adjacency matrix of the graph.

  20. New wearable walking-type continuous passive motion device for postsurgery walking rehabilitation.

    Science.gov (United States)

    Zhu, Yong; Nakamura, Masahiro; Horiuchi, Tadahiro; Kohno, Hideki; Takahashi, Rei; Terada, Hidetsugu; Haro, Hirotaka

    2013-07-01

    While total knee arthroplasty is useful for treating osteoarthritis of the knee, the success of this treatment depends on effective rehabilitation. The goal of this study was to develop an assistive device for post-total knee arthroplasty patients for walking rehabilitation and for shortening the hospitalization period. We developed a brace electronic assist system termed the knee assistive instrument for walking rehabilitation (KAI-R) to illustrate the need for training during postoperative rehabilitation. Sixteen osteoarthritis patients (1 male and 15 females; average age 68.9 years) who underwent total knee arthroplasty were analyzed before operation and 2-4 weeks after operation, and 25 healthy individuals (14 males and 11 females; average age 26.2 years) formed the control group. Based on the pre- and postoperative data on peak knee flexion angle, foot height, and walking velocity, we developed the KAI-R, which consists of an assistive mechanism for the knee joint, a hip joint support system, and a foot pressure sensor system and is driven by a CPU board that generates the walking pattern. We then tested the walking gait in seven healthy volunteers with and without KAI-R assistance. KAI-R increased the peak flexion angle of the knee and foot height in all seven volunteers; their range of motion of the knee joint was increased. However, KAI-R also decreased the walking velocity of subjects, which was explained by reaction delay and slightly compromised physical balance, which was caused by wearing the KAI-R. KAI-R is useful for gait improvement. In future studies, KAI-R will be investigated in a clinical trial for its ability for walking rehabilitation in post-total knee arthroplasty patients.

  1. Cookie branching random walks

    CERN Document Server

    Bartsch, Christian; Kochler, Thomas; Müller, Sebastian; Popov, Serguei

    2011-01-01

    We consider a branching random walk on $\\Z$, where the particles behave differently in visited and unvisited sites. Informally, each site on the positive half-line contains initially a cookie. On the first visit of a site its cookie is removed and particles at positions with a cookie reproduce and move differently from particles on sites without cookies. Therefore, the movement and the reproduction of the particles depend on the previous behaviour of the population of particles. We study the question if the process is recurrent or transient, i.e., whether infinitely many particles visit the origin or not.

  2. Collisions of Random Walks

    CERN Document Server

    Barlow, Martin T; Sousi, Perla

    2010-01-01

    A recurrent graph $G$ has the infinite collision property if two independent random walks on $G$, started at the same point, collide infinitely often a.s. We give a simple criterion in terms of Green functions for a graph to have this property, and use it to prove that a critical Galton-Watson tree with finite variance conditioned to survive, the incipient infinite cluster in $\\Z^d$ with $d \\ge 19$ and the uniform spanning tree in $\\Z^2$ all have the infinite collision property. For power-law combs and spherically symmetric trees, we determine precisely the phase boundary for the infinite collision property.

  3. A mathematical nature walk

    CERN Document Server

    Adam, John A

    2009-01-01

    How heavy is that cloud? Why can you see farther in rain than in fog? Why are the droplets on that spider web spaced apart so evenly? If you have ever asked questions like these while outdoors, and wondered how you might figure out the answers, this is a book for you. An entertaining and informative collection of fascinating puzzles from the natural world around us, A Mathematical Nature Walk will delight anyone who loves nature or math or both. John Adam presents ninety-six questions about many common natural phenomena--and a few uncommon ones--and then shows how to answer them using mostly b

  4. Persistence of random walk records

    Science.gov (United States)

    Ben-Naim, E.; Krapivsky, P. L.

    2014-06-01

    We study records generated by Brownian particles in one dimension. Specifically, we investigate an ordinary random walk and define the record as the maximal position of the walk. We compare the record of an individual random walk with the mean record, obtained as an average over infinitely many realizations. We term the walk ‘superior’ if the record is always above average, and conversely, the walk is said to be ‘inferior’ if the record is always below average. We find that the fraction of superior walks, S, decays algebraically with time, S ˜ t-β, in the limit t → ∞, and that the persistence exponent is nontrivial, β = 0.382 258…. The fraction of inferior walks, I, also decays as a power law, I ˜ t-α, but the persistence exponent is smaller, α = 0.241 608…. Both exponents are roots of transcendental equations involving the parabolic cylinder function. To obtain these theoretical results, we analyze the joint density of superior walks with a given record and position, while for inferior walks it suffices to study the density as a function of position.

  5. Quantum Walks on the Hypercube

    CERN Document Server

    Moore, Cristopher; Moore, Cristopher; Russell, Alexander

    2001-01-01

    Recently, it has been shown that one-dimensional quantum walks can mix more quickly than classical random walks, suggesting that quantum Monte Carlo algorithms can outperform their classical counterparts. We study two quantum walks on the n-dimensional hypercube, one in discrete time and one in continuous time. In both cases we show that the quantum walk mixes in (\\pi/4)n steps, faster than the O(n log n) steps required by the classical walk. In the continuous-time case, the probability distribution is {\\em exactly} uniform at this time. More importantly, these walks expose several subtleties in the definition of mixing time for quantum walks. Even though the continuous-time walk has an O(n) instantaneous mixing time at which it is precisely uniform, it never approaches the uniform distribution when the stopping time is chosen randomly as in [AharonovAKV2001]. Our analysis treats interference between terms of different phase more carefully than is necessary for the walk on the cycle; previous general bounds p...

  6. Physical implementation of quantum walks

    CERN Document Server

    Manouchehri, Kia

    2013-01-01

    Given the extensive application of random walks in virtually every science related discipline, we may be at the threshold of yet another problem solving paradigm with the advent of quantum walks. Over the past decade, quantum walks have been explored for their non-intuitive dynamics, which may hold the key to radically new quantum algorithms. This growing interest has been paralleled by a flurry of research into how one can implement quantum walks in laboratories. This book presents numerous proposals as well as actual experiments for such a physical realization, underpinned by a wide range of

  7. Rotor-Router Walks on Directed Covers of Graphs

    CERN Document Server

    Huss, Wilfried

    2012-01-01

    The aim of this paper is to study the behaviour of rotor-router walks on directed covers of finite graphs. The latter are also called in the literature trees with finitely many cone types or periodic trees. A rotor-router walk is a deterministic version of a random walk, in which the walker is routed to each of the neighbouring vertices in some fixed cyclic order. We study several quantities related to rotor-router walks such as: order of the rotor-router group, order of the root element in the rotor-router group and the connection with random walks. For random initial configurations of rotors, we also address the question of recurrence and transience of transfinite rotor-router walks. On homogeneous trees, the recurrence/transience was studied by Angel and Holroyd. We extend their theory and provide an example of a directed cover such that the rotor-router walk can be either recurrent or transient, depending only on the planar embedding of the periodic tree.

  8. Random-walk enzymes.

    Science.gov (United States)

    Mak, Chi H; Pham, Phuong; Afif, Samir A; Goodman, Myron F

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C→U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  9. Random-walk enzymes

    Science.gov (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  10. Random-walk enzymes

    Science.gov (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-01-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C → U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics. PMID:26465508

  11. Running for exercise mitigates age-related deterioration of walking economy.

    Science.gov (United States)

    Ortega, Justus D; Beck, Owen N; Roby, Jaclyn M; Turney, Aria L; Kram, Rodger

    2014-01-01

    Impaired walking performance is a key predictor of morbidity among older adults. A distinctive characteristic of impaired walking performance among older adults is a greater metabolic cost (worse economy) compared to young adults. However, older adults who consistently run have been shown to retain a similar running economy as young runners. Unfortunately, those running studies did not measure the metabolic cost of walking. Thus, it is unclear if running exercise can prevent the deterioration of walking economy. To determine if and how regular walking vs. running exercise affects the economy of locomotion in older adults. 15 older adults (69 ± 3 years) who walk ≥ 30 min, 3x/week for exercise, "walkers" and 15 older adults (69 ± 5 years) who run ≥ 30 min, 3x/week, "runners" walked on a force-instrumented treadmill at three speeds (0.75, 1.25, and 1.75 m/s). We determined walking economy using expired gas analysis and walking mechanics via ground reaction forces during the last 2 minutes of each 5 minute trial. We compared walking economy between the two groups and to non-aerobically trained young and older adults from a prior study. Older runners had a 7-10% better walking economy than older walkers over the range of speeds tested (p = .016) and had walking economy similar to young sedentary adults over a similar range of speeds (p =  .237). We found no substantial biomechanical differences between older walkers and runners. In contrast to older runners, older walkers had similar walking economy as older sedentary adults (p =  .461) and ∼ 26% worse walking economy than young adults (peconomy whereas walking for exercise appears to have minimal effect on the age-related deterioration in walking economy.

  12. Two-color walking Peregrine solitary waves.

    Science.gov (United States)

    Baronio, Fabio; Chen, Shihua; Mihalache, Dumitru

    2017-09-15

    We study the extreme localization of light, evolving upon a non-zero background, in two-color parametric wave interaction in nonlinear quadratic media. We report the existence of quadratic Peregrine solitary waves, in the presence of significant group-velocity mismatch between the waves (or Poynting vector beam walk-off), in the regime of cascading second-harmonic generation. This finding opens a novel path for the experimental demonstration of extreme rogue waves in ultrafast quadratic nonlinear optics.

  13. The journey begins at 8am. Destination: unknown Time machine launches quest of discovery: how existence began 13.7 billion years ago.

    CERN Multimedia

    Henderson, Mark

    2008-01-01

    A story that began 13.7 billion years ago will start a new chapter this morning. Since the big bang threw space and time into being, no living creature of which we know has been able to discern just what happened in the moments at which existence began. (2 pages)

  14. Terminology concepts and structural features of technique of walking with sticks

    Directory of Open Access Journals (Sweden)

    Shepelenko G.P.

    2012-12-01

    Full Text Available The purpose of work is an analysis of technique of walking with sticks. The views of specialists are shown to the problem of health of a man and influencing of walking with sticks on his level. Biomechanics phases of implementation of technique of walking are certain and described. Terminology concepts and forces which operate at walking with sticks are exposed. The analysis of general parameters which characterize walking is resulted. The most meaningful groups of muscles which accept active voice at walking are considered. The most essential directions of walking are exposed. Intercommunications of motions are certain at walking. The biomechanics criteria of motions are selected. It is marked that the general influencing of walking with sticks on the organism of man is related to the improvement of the functional state of the central nervous system, indemnifications of power inputs, by functional changes in the system of circulation of blood and decline of disease. Possibilities of application of walking with sticks are shown as a physical loading for the people of different age groups. Resulted recommendation on the technique of walking with sticks and its influencing on a health of man.

  15. Quantum walks and search algorithms

    CERN Document Server

    Portugal, Renato

    2013-01-01

    This book addresses an interesting area of quantum computation called quantum walks, which play an important role in building quantum algorithms, in particular search algorithms. Quantum walks are the quantum analogue of classical random walks. It is known that quantum computers have great power for searching unsorted databases. This power extends to many kinds of searches, particularly to the problem of finding a specific location in a spatial layout, which can be modeled by a graph. The goal is to find a specific node knowing that the particle uses the edges to jump from one node to the next. This book is self-contained with main topics that include: Grover's algorithm, describing its geometrical interpretation and evolution by means of the spectral decomposition of the evolution operater Analytical solutions of quantum walks on important graphs like line, cycles, two-dimensional lattices, and hypercubes using Fourier transforms Quantum walks on generic graphs, describing methods to calculate the limiting d...

  16. Qualitative developmental research among low income African American adults to inform a social marketing campaign for walking.

    Science.gov (United States)

    Wilson, Dawn K; St George, Sara M; Trumpeter, Nevelyn N; Coulon, Sandra M; Griffin, Sarah F; Wandersman, Abe; Forthofer, Melinda; Gadson, Barney; Brown, Porschia V

    2013-03-05

    This study describes the development of a social marketing campaign for increasing walking in a low income, high crime community as part of the Positive Action for Today's Health (PATH) trial. Focus groups were conducted with 52 African American adults (ages 18 to 65 yrs), from two underserved communities to develop themes for a social marketing campaign to promote walking. Participants responded to questions concerning social marketing principles related to product, price, place, promotion, and positioning for increasing neighbourhood walking. Focus group data informed the development of the campaign objectives that were derived from the "5 Ps" to promote physical and mental health, social connectedness, safety, and confidence in walking regularly. Focus group themes indicated that physical and mental health benefits of walking were important motivators. Walking for social reasons was also important for overcoming barriers to walking. Police support from trusted officers while walking was also essential to promoting safety for walking. Print materials were developed by the steering committee, with a 12-month calendar and door hangers delivered to residents' homes to invite them to walk. Pride Stride walks empowered community walkers to serve as peer leaders for special walking events to engage new walkers. Essential elements for developing culturally tailored social marketing interventions for promoting walking in underserved communities are outlined for future researchers.

  17. Human treadmill walking needs attention

    Directory of Open Access Journals (Sweden)

    Daniel Olivier

    2006-08-01

    Full Text Available Abstract Background The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor task. Varying the level of difficulty of the reaction time (RT task is used to verify the priority of allocation of attentional resources. Methods 11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration. Results Gait cycle duration was unchanged (p > 0.05 by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p 0.05 was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance. Conclusion We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.

  18. Water-walking devices

    Science.gov (United States)

    Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.

    We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using highspeed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.

  19. Walking for art's sake

    CERN Multimedia

    2005-01-01

      The man who compared himself to a proton ! On 20 May, Gianni Motti went down into the LHC tunnel and walked around the 27 kilometres of the underground ring at an average, unaccelerated pace of 5 kph. This was an artistic rather than an athletic performance, aimed at drawing a parallel between the fantastic speed of the beams produced by the future accelerator and the leisurely stroll of a human. The artist, who hails from Lombardy, was accompanied by cameraman Ivo Zanetti, who filmed the event from start to finish, and physicist Jean-Pierre Merlo. The first part of the film can be seen at the Villa Bernasconi, 8 route du Grand-Lancy, Grand Lancy, until 26 June.

  20. Walking for art's sake

    CERN Document Server

    2005-01-01

    The man who compared himself to a proton ! On 20 May, Gianni Motti went down into the LHC tunnel and walked around the 27 kilometres of the underground ring at an average, unaccelerated pace of 5 kph. This was an artistic rather than an athletic performance, aimed at drawing a parallel between the fantastic speed of the beams produced by the future accelerator and the leisurely stroll of a human. The artist, who hails from Lombardy, was accompanied by cameraman Ivo Zanetti, who filmed the event from start to finish, and physicist Jean-Pierre Merlo. The first part of the film can be seen at the Villa Bernasconi, 8 route du Grand-Lancy, Grand Lancy, until 26 June.

  1. walk around Irkutsk

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2011-08-01

    Full Text Available It is noteworthy that this country develops through two types of events: either through a jubilee or through a catastrophe.It seems that Irkutsk Airport will be built only after the next crash. At least the interest to this problem returns regularly after sad events, and this occurs almost half a century (a jubilee, too! – the Council of Ministers decided to relocate the Airport away from the city as long ago as 1962. The Airport does not relate to the topic of this issue, but an attentive reader understands that it is our Carthage, and that the Airport should be relocated. The Romans coped with it faster and more effectively.Back to Irkutsk’s jubilee, we should say that we will do without blare of trumpets. We will just make an unpretentious walk around the city in its summer 350. Each our route covers new (some of them have been completed by the jubilee and old buildings, some of them real monuments. All these buildings are integrated into public spaces of different quality and age.We will also touch on the problems, for old houses, especially the wooden ones often provoke a greedy developer to demolish or to burn them down. Thus a primitive thrift estimates an output of additional square meters. Not to mention how attractive it is to seize public spaces without demolition or without reallocation of the dwellers. Or, rather, the one who is to preserve, to cherish and to improve such houses for the good of the citizens never speaks about this sensitive issue. So we have to do it.Walking is a no-hurry genre, unlike the preparation for the celebration. Walking around the city you like is a pleasant and cognitive process. It will acquaint the architects with the works of their predecessors and colleagues. We hope that such a walk may be interesting for Irkutsk citizens and visitors, too. Isn’t it interesting to learn “at first hand” the intimate details of the restoration of the Trubetskoys’ estate

  2. Walking indoors, walking outdoors: an fMRI study

    Directory of Open Access Journals (Sweden)

    Riccardo eDalla Volta

    2015-10-01

    Full Text Available An observation/execution matching system for walking has not been assessed yet. The present fMRI study was aimed at assessing whether, as for object-directed actions, an observation/execution matching system is active for walking and whether the spatial context of walking (open or narrow space recruits different neural correlates. Two experimental conditions were employed. In the execution condition, while being scanned, participants performed walking on a rolling cylinder located just outside the scanner. The same action was performed also while observing a video presenting either an open space (a country field or a narrow space (a corridor. In the observation condition, participants observed a video presenting an individual walking on the same cylinder on which the actual action was executed, the open space video and the narrow space video, respectively. Results showed common bilateral activations in the dorsal premotor/supplementary motor areas and in the posterior parietal lobe for both execution and observation of walking, thus supporting a matching system for this action. Moreover, specific sectors of the occipital-temporal cortex and the middle temporal gyrus were consistently active when processing a narrow space versus an open one, thus suggesting their involvement in the visuo-motor transformation required when walking in a narrow space. We forward that the present findings may have implications for rehabilitation of gait and sport training.

  3. Effects of downhill walking training on aerobic and neuromuscular fitness of young adults

    Directory of Open Access Journals (Sweden)

    Leonardo Coelho Rabello de Lima

    2015-07-01

    Full Text Available Eccentric exercise training using low intensity-high volume approach has been performed to improve maximal muscle strength and power. The aim of this study was to compare the effects of short-term downhill walking and level walking training on lower limb strength and maximal oxygen uptake of active individuals. Eighteen young adults were divided into level walking group (n = 9 or downhill walking training group (n = 9. Both groups performed a four-week training program. The level walking group performed seven level walking sessions per week, while the downhill walking group walked downhill (-16% in the same weekly frequency. One week before and one week after the training protocol, maximal oxygen uptake, muscle-bone cross-sectional area and isometric peak torque of knee extensors and plantar flexors were assessed for both groups. A significant group vs. time interaction was found only for cross sectional area of plantar flexors (PF, showing increases for the downhill walking group (112.6 ± 28.9 cm2 vs. 115.9 ± 29 cm2 but not for the level walking group (94.9 ± 23.3 cm2vs. 94.6 ± 228 cm2. Maximal oxygen uptake remained unaltered after training for both groups and IPT was increased after training for both groups. It was concluded that short-term downhill walking training does not seem to be efficient in promoting improvements in cardiorrespiratory fitness of young adults. However, it seems to promote gains in some variables related to neuromuscular fitness.

  4. To walk or not to walk: insights from a qualitative description study with women suffering from fibromyalgia.

    Science.gov (United States)

    Sanz-Baños, Yolanda; Pastor, María-Ángeles; Velasco, Lilian; López-Roig, Sofía; Peñacoba, Cecilia; Lledo, Ana; Rodríguez, Charo

    2016-08-01

    Walking improves health outcomes in fibromyalgia; however, there is low adherence to this practice. The aim of this research was to explore the beliefs of women suffering from fibromyalgia toward walking, and the meaning that they attribute to the behavior of walking as part of their fibromyalgia treatment. This study is a qualitative description research. Forty-six (46) women suffering from fibromyalgia and associated with local fibromyalgia associations located in four different Spanish cities (Elche, Alicante, Madrid, and Talavera de la Reina) participated in focus group discussions in the summer 2012. Thematic content analysis was performed in transcribed verbatim from interviews. Participants perceived several inhibitors for walking even when they had positive beliefs toward its therapeutic value. Whereas participants believed that walking can generate improvement in their disease and their health in general, they did not feel able to actually do so given their many physical impediments. Furthermore, participants struggled with social isolation and stigma, which was lessened through the conscious support of family. Advice from family doctors was also a very important facilitator to participants. In a health care delivery context that favors person-centered care, and in order to foster adherence to walking-based fibromyalgia treatments, it is recommended that therapeutic walking programs be tailored to each woman' individual circumstances, and developed in close collaboration with them to help them increase control over their health and their condition.

  5. Comparação das respostas fisiológicas, perceptuais e afetivas durante caminhada em ritmo autosselecionado por mulheres adultas de três diferentes faixas etárias Comparison of the physiological, perception and affective responses during treadmill walking at self-selected pace by adult women of three different age groups

    Directory of Open Access Journals (Sweden)

    Cosme Franklim Buzzachera

    2010-10-01

    Full Text Available Comparar as respostas fisiológicas, perceptuais e afetivas durante caminhada em ritmo autosselecionado por mulheres adultas de três diferentes faixas etárias. Métodos: Foram investigados 66 sujeitos do sexo feminino, previamente sedentários, distribuídos de acordo com a sua idade cronológica nos seguintes grupos: GI (20,0-25,0 anos, n = 22, GII (30,0-35,0 anos, n = 22 e GIII (40,0-45,0 anos, n = 22. Todos os participantes foram submetidos a (i pré-avaliação médica, avaliação antropométrica e processo de familiarização, (ii teste incremental máximo em esteira, e (iii um teste de 20-minutos de caminhada em ritmo autosselecionado em esteira. As respostas fisiológicas (consumo de oxigênio, O2, e frequência cardíaca, FC foram mensuradas continuamente durante a realização do teste de 20-minutos de caminhada em ritmo autosselecionado. Por sua vez, as respostas perceptuais (percepção subjetiva de esforço, PSE e afetivas foram determinadas a cada intervalo de cinco minutos do teste. Para a análise estatística, empregou-se uma ANOVA de um fator (faixa etária, adotando-se um valor de p To compare the physiological, perception and affective responses during treadmill walking at a self-selected pace by previously sedentary women from three age groups. Methods: Sixty-six healthy women were assigned into three groups according to their age: GI (20.0-25.0 yr, n = 22, GII (30.0-35.0 yr, n = 22 and GIII (40.0-45.0 yr, n = 22. Each participant performed (i an initial medical screening, anthropometric assessment and familiarization; (ii an incremental treadmill test to determine O2max; and (iii a 20-min treadmill walking bout at a self-selected pace. During the 20-min of treadmill walking at a self-selected pace, the physiological (oxygen uptake, O2 and heart rate, HR responses were continuously recorded. The perception (Borg-RPE for the overall body, 6-20 and affective (Feeling Scale responses were measured every 5 min throughout the

  6. Mindful Walking in Psychologically Distressed Individuals: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    M. Teut

    2013-01-01

    Full Text Available Background. The aim of this randomized, controlled study was to investigate the effectiveness of a mindful walking program in patients with high levels of perceived psychological distress. Methods. Participants aged between 18 and 65 years with moderate to high levels of perceived psychological distress were randomized to 8 sessions of mindful walking in 4 weeks (each 40 minutes walking, 10 minutes mindful walking, 10 minutes discussion or to no study intervention (waiting group. Primary outcome parameter was the difference to baseline on Cohen’s Perceived Stress Scale (CPSS after 4 weeks between intervention and control. Results. Seventy-four participants were randomized in the study; 36 (32 female, 52.3 ± 8.6 years were allocated to the intervention and 38 (35 female, 49.5 ± 8.8 years to the control group. Adjusted CPSS differences after 4 weeks were −8.8 [95% CI: −10.8; −6.8] (mean 24.2 [22.2; 26.2] in the intervention group and −1.0 [−2.9; 0.9] (mean 32.0 [30.1; 33.9] in the control group, resulting in a highly significant group difference (. Conclusion. Patients participating in a mindful walking program showed reduced psychological stress symptoms and improved quality of life compared to no study intervention. Further studies should include an active treatment group and a long-term follow-up.

  7. Random walks, random fields, and disordered systems

    CERN Document Server

    Černý, Jiří; Kotecký, Roman

    2015-01-01

    Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

  8. Visual control of walking velocity.

    Science.gov (United States)

    François, Matthieu; Morice, Antoine H P; Bootsma, Reinoud J; Montagne, Gilles

    2011-06-01

    Even if optical correlates of self-motion velocity have already been identified, their contribution to the control of displacement velocity remains to be established. In this study, we used a virtual reality set-up coupled to a treadmill to test the role of both Global Optic Flow Rate (GOFR) and Edge Rate (ER) in the regulation of walking velocity. Participants were required to walk at a constant velocity, corresponding to their preferred walking velocity, while eye height and texture density were manipulated. This manipulation perturbed the natural relationship between the actual walking velocity and its optical specification by GOFR and ER, respectively. Results revealed that both these sources of information are indeed used by participants to control walking speed, as demonstrated by a slowing down of actual walking velocity when the optical specification of velocity by either GOFR or ER gives rise to an overestimation of actual velocity, and vice versa. Gait analyses showed that these walking velocity adjustments result from simultaneous adaptations in both step length and step duration. The role of visual information in the control of self-motion velocity is discussed in relation with other factors.

  9. Characterisation of walking loads by 3D inertial motion tracking

    Science.gov (United States)

    Van Nimmen, K.; Lombaert, G.; Jonkers, I.; De Roeck, G.; Van den Broeck, P.

    2014-09-01

    The present contribution analyses the walking behaviour of pedestrians in situ by 3D inertial motion tracking. The technique is first tested in laboratory experiments with simultaneous registration of the ground reaction forces. The registered motion of the pedestrian allows for the identification of stride-to-stride variations, which is usually disregarded in the simulation of walking forces. Subsequently, motion tracking is used to register the walking behaviour of (groups of) pedestrians during in situ measurements on a footbridge. The calibrated numerical model of the structure and the information gathered using the motion tracking system enables detailed simulation of the step-by-step pedestrian induced vibrations. Accounting for the in situ identified walking variability of the test-subjects leads to a significantly improved agreement between the measured and the simulated structural response.

  10. Routine physiotherapy does not induce a cardiorespiratory training effect post-stroke, regardless of walking ability.

    Science.gov (United States)

    Kuys, Suzanne; Brauer, Sandra; Ada, Louise

    2006-12-01

    Cardiorespiratory fitness is increasingly being recognized as an impairment requiring physiotherapy intervention after stroke. The present study seeks to investigate if routine physiotherapy treatment is capable of inducing a cardiorespiratory training effect and if stroke patients attending physiotherapy who are unable to walk experience less cardiorespiratory stress during physiotherapy when compared to those who are able to walk. A descriptive, observational study, with heart rate monitoring and video-recording of physiotherapy rehabilitation, was conducted. Thirty consecutive stroke patients from a geriatric and rehabilitation unit of a tertiary metropolitan hospital, admitted for rehabilitation, and requiring physiotherapy were included in the study. The main measures of the study were duration (time) and intensity (percentage of heart rate reserve) of standing and walking activities during physiotherapy rehabilitation for non-walking and walking stroke patients. Stroke patients spent an average of 21 minutes participating in standing and walking activities that were capable of inducing a cardiorespiratory training effect. Stroke patients who were able to walk spent longer in these activities during physiotherapy rehabilitation than non-walking stroke patients (p heart rate reserve (HRR) during standing and walking activities was insufficient to result in a cardiorespiratory training effect, with a maximum of 35% achieved for the stroke patients able to walk and 30% for those unable to walk. Routine physiotherapy rehabilitation had insufficient duration and intensity to result in a cardiorespiratory training effect in our group of stroke patients.

  11. Effects of a 6-month exercise program pilot study on walking economy, peak physiological characteristics, and walking performance in patients with peripheral arterial disease

    Directory of Open Access Journals (Sweden)

    Crowther RG

    2012-04-01

    Full Text Available Robert G Crowther1, Anthony S Leicht1, Warwick L Spinks1, Kunwarjit Sangla2, Frank Quigley2, Jonathan Golledge2,31Institute of Sport and Exercise Science, James Cook University, Townsville, Queensland, Australia; 2Townsville Hospital, Townsville, Queensland, Australia; 3The Vascular Biology Unit, James Cook University, Townsville, Queensland, AustraliaAbstract : The purpose of this study was to examine the effects of a 6-month exercise program on submaximal walking economy in individuals with peripheral arterial disease and intermittent claudication (PAD-IC. Participants (n = 16 were randomly allocated to either a control PAD-IC group (CPAD-IC, n = 6 which received standard medical therapy, or a treatment PAD-IC group (TPAD-IC; n = 10 which took part in a supervised exercise program. During a graded treadmill test, physiological responses, including oxygen consumption, were assessed to calculate walking economy during submaximal and maximal walking performance. Differences between groups at baseline and post-intervention were analyzed via Kruskal–Wallis tests. At baseline, CPAD-IC and TPAD-IC groups demonstrated similar walking performance and physiological responses. Postintervention, TPAD-IC patients demonstrated significantly lower oxygen consumption during the graded exercise test, and greater maximal walking performance compared to CPAD-IC. These preliminary results indicate that 6 months of regular exercise improves both submaximal walking economy and maximal walking performance, without significant changes in maximal walking economy. Enhanced walking economy may contribute to physiological efficiency, which in turn may improve walking performance as demonstrated by PAD-IC patients following regular exercise programs.Keywords: vascular disease, peripheral vascular disease, walking economy

  12. The Dead Walk

    Directory of Open Access Journals (Sweden)

    Bill Phillips

    2014-02-01

    Full Text Available Monsters have always enjoyed a significant presence in the human imagination, and religion was instrumental in replacing the physical horror they engendered with that of a moral threat. Zombies, however, are amoral – their motivation purely instinctive and arbitrary, yet they are, perhaps, the most loathed of all contemporary monsters. One explanation for this lies in the theory of the uncanny valley, proposed by robotics engineer Masahiro Mori. According to the theory, we reserve our greatest fears for those things which seem most human, yet are not – such as dead bodies. Such a reaction is most likely a survival mechanism to protect us from danger and disease – a mechanism even more essential when the dead rise up and walk. From their beginnings zombies have reflected western societies’ greatest fears – be they of revolutionary Haitians, women, or communists. In recent years the rise in the popularity of the zombie in films, books and television series reflects our fears for the planet, the economy, and of death itself

  13. Quantum Walk with Jumps

    CERN Document Server

    Lavička, H; Kiss, T; Lutz, E; Jex, I

    2011-01-01

    We analyze a special class of 1-D quantum walks (QWs) realized using optical multi-ports. We assume non-perfect multi-ports showing errors in the connectivity, i.e. with a small probability the multi- ports can connect not to their nearest neighbor but to another multi-port at a fixed distance - we call this a jump. We study two cases of QW with jumps where multiple displacements can emerge at one timestep. The first case assumes time-correlated jumps (static disorder). In the second case, we choose the positions of jumps randomly in time (dynamic disorder). The probability distributions of position of the QW walker in both instances differ significantly: dynamic disorder leads to a Gaussian-like distribution, while for static disorder we find two distinct behaviors depending on the parity of jump size. In the case of even-sized jumps, the distribution exhibits a three-peak profile around the position of the initial excitation, whereas the probability distribution in the odd case follows a Laplace-like discre...

  14. Big power from walking

    Science.gov (United States)

    Illenberger, Patrin K.; Madawala, Udaya K.; Anderson, Iain A.

    2016-04-01

    Dielectric Elastomer Generators (DEG) offer an opportunity to capture the energy otherwise wasted from human motion. By integrating a DEG into the heel of standard footwear, it is possible to harness this energy to power portable devices. DEGs require substantial auxiliary systems which are commonly large, heavy and inefficient. A unique challenge for these low power generators is the combination of high voltage and low current. A void exists in the semiconductor market for devices that can meet these requirements. Until these become available, existing devices must be used in an innovative way to produce an effective DEG system. Existing systems such as the Bi-Directional Flyback (BDFB) and Self Priming Circuit (SPC) are an excellent example of this. The BDFB allows full charging and discharging of the DEG, improving power gained. The SPC allows fully passive voltage boosting, removing the priming source and simplifying the electronics. This paper outlines the drawbacks and benefits of active and passive electronic solutions for maximizing power from walking.

  15. Integrated photonic quantum walks

    Science.gov (United States)

    Gräfe, Markus; Heilmann, René; Lebugle, Maxime; Guzman-Silva, Diego; Perez-Leija, Armando; Szameit, Alexander

    2016-10-01

    Over the last 20 years quantum walks (QWs) have gained increasing interest in the field of quantum information science and processing. In contrast to classical walkers, quantum objects exhibit intrinsic properties like non-locality and non-classical many-particle correlations, which renders QWs a versatile tool for quantum simulation and computation as well as for a deeper understanding of genuine quantum mechanics. Since they are highly controllable and hardly interact with their environment, photons seem to be ideally suited quantum walkers. In order to study and exploit photonic QWs, lattice structures that allow low loss coherent evolution of quantum states are demanded. Such requirements are perfectly met by integrated optical waveguide devices that additionally allow a substantial miniaturization of experimental settings. Moreover, by utilizing the femtosecond direct laser writing technique three-dimensional waveguide structures are capable of analyzing QWs also on higher dimensional geometries. In this context, advances and findings of photonic QWs are discussed in this review. Various concepts and experimental results are presented covering, such as different quantum transport regimes, the Boson sampling problem, and the discrete fractional quantum Fourier transform.

  16. Walking Robot Locomotion System Conception

    Directory of Open Access Journals (Sweden)

    Ignatova D.

    2014-09-01

    Full Text Available This work is a brief analysis on the application and perspective of using the walking robots in different areas in practice. The most common characteristics of walking four legs robots are presented here. The specific features of the applied actuators in walking mechanisms are also shown in the article. The experience of Institute of Mechanics - BAS is illustrated in creation of Spiroid and Helicon1 gears and their assembly in actuation of studied robots. Loading on joints reductors of robot legs is modelled, when the geometrical and the walking parameters of the studied robot are preliminary defined. The obtained results are purposed for designing the control of the loading of reductor type Helicon in the legs of the robot, when it is experimentally tested.

  17. Quantum Snake Walk on Graphs

    CERN Document Server

    Rosmanis, Ansis

    2010-01-01

    I introduce a new type of continuous-time quantum walk on graphs called the quantum snake walk, the basis states of which are fixed-length paths (snakes) in the underlying graph. First I analyze the quantum snake walk on the line, and I show that, even though most states stay localized throughout the evolution, there are specific states which most likely move on the line as wave packets with momentum inversely proportional to the length of the snake. Next I discuss how an algorithm based on the quantum snake walk might be able to solve an extended version of the glued trees problem which asks to find a path connecting both roots of the glued trees graph. No efficient quantum algorithm solving this problem is known yet.

  18. Localization of reinforced random walks

    CERN Document Server

    Tarrès, Pierre

    2011-01-01

    We describe and analyze how reinforced random walks can eventually localize, i.e. only visit finitely many sites. After introducing vertex and edge self-interacting walks on a discrete graph in a general setting, and stating the main results and conjectures so far on the topic, we present martingale techniques that provide an alternative proof of the a.s. localization of vertex-reinforced random walks (VRRWs) on the integers on finitely many sites and, with positive probability, on five consecutive sites, initially proved by Pemantle and Volkov (1999). Next we introduce the continuous time-lines representation (sometimes called Rubin construction) and its martingale counterpart, and explain how it has been used to prove localization of some reinforced walks on one attracting edge. Then we show how a modified version of this construction enables one to propose a new short proof of the a.s. localization of VRRWs on five sites on Z.

  19. Bouchaud walks with variable drift

    CERN Document Server

    Parra, Manuel Cabezas

    2010-01-01

    In this paper we study a sequence of Bouchaud trap models on $\\mathbb{Z}$ with drift. We analyze the possible scaling limits for a sequence of walks, where we make the drift decay to 0 as we rescale the walks. Depending on the speed of the decay of the drift we obtain three different scaling limits. If the drift decays slowly as we rescale the walks we obtain the inverse of an \\alpha$-stable subordinator as scaling limit. If the drift decays quickly as we rescale the walks, we obtain the F.I.N. diffusion as scaling limit. There is a critical speed of decay separating these two main regimes, where a new process appears as scaling limit. This critical speed is related to the index $\\alpha$ of the inhomogeneity of the environment.

  20. Attentional costs of walking are not affected by variations in lateral balance demands in young and older adults.

    Science.gov (United States)

    Mazaheri, Masood; Roerdink, Melvyn; Duysens, Jacques; Beek, Peter J; Peper, C Lieke E

    2016-05-01

    Increased attentional costs of walking in older adults have been attributed to age-related changes in visuomotor and/or balance control of walking. The present experiment was conducted to examine the hypothesis that attentional costs of walking vary with lateral balance demands during walking in young and older adults. Twenty young and twenty older adults walked on a treadmill at their preferred walking speed under five conditions: unconstrained normal walking, walking on projected visual lines corresponding to either the participant's preferred step width or 50% thereof (i.e. increased balance demand), and walking within low- and high-stiffness lateral stabilization frames (i.e. lower balance demands). Attentional costs were assessed using a probe reaction-time task during these five walking conditions, normalized to baseline performance as obtained during sitting. Both imposed step-width conditions were more attentionally demanding than the three other conditions, in the absence of any other significant differences between conditions. These effects were similar in the two groups. The results indicate that the attentional costs of walking were, in contrast to what has been postulated previously, not influenced by lateral balance demands. The observed difference in attentional costs between normal walking and both visual lines conditions suggests that visuomotor control processes, rather than balance control, strongly affect the attentional costs of walking. A tentative explanation of these results may be that visuomotor control processes are mainly governed by attention-demanding cortical processes, whereas balance is regulated predominantly subcortically.

  1. Efficacy of walking exercise in promoting cognitive-psychosocial functions in men with prostate cancer receiving androgen deprivation therapy

    Directory of Open Access Journals (Sweden)

    Lee C

    2012-07-01

    Full Text Available Abstract Background Prostate cancer is the most commonly diagnosed non-melanoma cancer among men. Androgen deprivation therapy (ADT has been the core therapy for men with advanced prostate cancer. It is only in recent years that clinicians began to recognize the cognitive-psychosocial side effects from ADT, which significantly compromise the quality of life of prostate cancer survivors. The objectives of the study are to determine the efficacy of a simple and accessible home-based, walking exercise program in promoting cognitive and psychosocial functions of men with prostate cancer receiving ADT. Methods A 6-month prospective, single-blinded, randomized controlled trial will be conducted to compare the Exercise Group with the Control Group. Twenty men with prostate cancer starting ADT will be recruited and randomly assigned to one of the two groups: the Exercise Group will receive instructions in setting up an individualized 6-month home-based, walking exercise program, while the Control Group will receive standard medical advice from the attending physician. The primary outcomes will be psychosocial and cognitive functions. Cognitive functions including memory, attention, working memory, and executive function will be assessed using a battery of neurocognitive tests at baseline and 6 months. Psychosocial functions including depression, anxiety and self-esteem will be assessed at baseline, 3 and 6 months using the Center for Epidemiological Studies Depression Scale, Spielberger State-Trait Anxiety Inventory, and Rosenberg Self-Esteem Scale. Discussion The significance of the cognitive-psychosocial side effects of ADT in men with prostate cancer has only been recently recognized, and the management remains unclear. This study addresses this issue by designing a simple and accessible home-based, exercise program that may potentially have significant impact on reducing the cognitive and psychosocial side effects of ADT, and ultimately

  2. Integration of Human Walking Gyroscopic Data Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Vincent Bonnet

    2013-12-01

    Full Text Available The present study was aimed at evaluating the Empirical Mode Decomposition (EMD method to estimate the 3D orientation of the lower trunk during walking using the angular velocity signals generated by a wearable inertial measurement unit (IMU and notably flawed by drift. The IMU was mounted on the lower trunk (L4-L5 with its active axes aligned with the relevant anatomical axes. The proposed method performs an offline analysis, but has the advantage of not requiring any parameter tuning. The method was validated in two groups of 15 subjects, one during overground walking, with 180° turns, and the other during treadmill walking, both for steady-state and transient speeds, using stereophotogrammetric data. Comparative analysis of the results showed that the IMU/EMD method is able to successfully detrend the integrated angular velocities and estimate lateral bending, flexion-extension as well as axial rotations of the lower trunk during walking with RMS errors of 1 deg for straight walking and lower than 2.5 deg for walking with turns.

  3. Effects of virtual reality training using Nintendo Wii and treadmill walking exercise on balance and walking for stroke patients.

    Science.gov (United States)

    Bang, Yo-Soon; Son, Kyung Hyun; Kim, Hyun Jin

    2016-11-01

    [Purpose] The purpose of this study is to investigate the effects of virtual reality training using Nintendo Wii on balance and walking for stroke patients. [Subjects and Methods] Forty stroke patients with stroke were randomly divided into two exercise program groups: virtual reality training (n=20) and treadmill (n=20). The subjects underwent their 40-minute exercise program three times a week for eight weeks. Their balance and walking were measured before and after the complete program. We measured the left/right weight-bearing and the anterior/posterior weight-bearing for balance, as well as stance phase, swing phase, and cadence for walking. [Results] For balance, both groups showed significant differences in the left/right and anterior/posterior weight-bearing, with significant post-program differences between the groups. For walking, there were significant differences in the stance phase, swing phase, and cadence of the virtual reality training group. [Conclusion] The results of this study suggest that virtual reality training providing visual feedback may enable stroke patients to directly adjust their incorrect weight center and shift visually. Virtual reality training may be appropriate for patients who need improved balance and walking ability by inducing their interest for them to perform planned exercises on a consistent basis.

  4. Increased walking variability in elderly persons with congestive heart failure

    Science.gov (United States)

    Hausdorff, J. M.; Forman, D. E.; Ladin, Z.; Goldberger, A. L.; Rigney, D. R.; Wei, J. Y.

    1994-01-01

    OBJECTIVES: To determine the effects of congestive heart failure on a person's ability to walk at a steady pace while ambulating at a self-determined rate. SETTING: Beth Israel Hospital, Boston, a primary and tertiary teaching hospital, and a social activity center for elderly adults living in the community. PARTICIPANTS: Eleven elderly subjects (aged 70-93 years) with well compensated congestive heart failure (NY Heart Association class I or II), seven elderly subjects (aged 70-79 years) without congestive heart failure, and 10 healthy young adult subjects (aged 20-30 years). MEASUREMENTS: Subjects walked for 8 minutes on level ground at their own selected walking rate. Footswitches were used to measure the time between steps. Step rate (steps/minute) and step rate variability were calculated for the entire walking period, for 30 seconds during the first minute of the walk, for 30 seconds during the last minute of the walk, and for the 30-second period when each subject's step rate variability was minimal. Group means and 5% and 95% confidence intervals were computed. MAIN RESULTS: All measures of walking variability were significantly increased in the elderly subjects with congestive heart failure, intermediate in the elderly controls, and lowest in the young subjects. There was no overlap between the three groups using the minimal 30-second variability (elderly CHF vs elderly controls: P congestive heart failure when using the overall variability. For all four measures, there was no overlap in any of the confidence intervals, and all group means were significantly different (P < 0.05).

  5. Interindividual differences in H reflex modulation during normal walking.

    Science.gov (United States)

    Simonsen, Erik B; Dyhre-Poulsen, Poul; Alkjaer, Tine; Aagaard, Per; Magnusson, S Peter

    2002-01-01

    Based on previous studies, at least two different types of soleus Hoffmann (H) reflex modulation were likely to be found during normal human walking. Accordingly, the aim of the present study was to identify different patterns of modulation of the soleus H reflex and to examine whether or not subjects with different H reflex modulation would exhibit different walking mechanics and different EMG activity. Fifteen subjects walked across two force platforms at 4.5 km/h (+/-10%) while the movements were recorded on video. The soleus H reflex and EMG activity were recorded separately during treadmill walking at 4.5 km/h. Using a two-dimensional analysis joint angles, angular velocities, accelerations, linear velocities and accelerations were calculated, and net joint moments about the ankle, knee and hip joint were computed by inverse dynamics from the video and force plate data. Six subjects (group S) showed a suppressed H reflex during the swing phase, and 9 subjects (group LS) showed increasing reflex excitability during the swing phase. The plantar flexor dominated moment about the ankle joint was greater for group LS. In contrast, the extensor dominated moment about the knee joint was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike.

  6. Comparison of forward walking and backward walking in stroke hemiplegia patients focusing on the paretic side

    Science.gov (United States)

    Makino, Misato; Takami, Akiyoshi; Oda, Atsushi

    2017-01-01

    [Purpose] To investigate the features of backward walking in stroke patients with hemiplegia by focusing on the joint movements and moments of the paretic side, walking speed, stride length, and cadence. [Subjects and Methods] Nine stroke patients performed forward walking and backward walking along a 5-m walkway. Walking speed and stride length were self-selected. Movements were measured using a three-dimensional motion analysis system and a force plate. One walking cycle of the paretic side was analyzed. [Results] Walking speed, stride length, and cadence were significantly lower in backward walking than in forward walking. Peak hip extension was significantly lower in backward walking and peak hip flexion moment, knee extension moment, and ankle dorsiflexion and plantar flexion moments were lower in backward walking. [Conclusion] Unlike forward walking, backward walking requires conscious hip joint extension. Conscious extension of the hip joint is hard for stroke patients with hemiplegia. Therefore, the range of hip joint movement declined in backward walking, and walking speed and stride length also declined. The peak ankle plantar flexion moment was significantly lower in backward walking than in forward walking, and it was hard to generate propulsion power in backward walking. These difficulties also affected the walking speed. PMID:28265136

  7. Effects of underwater treadmill walking training on the peak torque of the knee in hemiplegic patients.

    Science.gov (United States)

    Lee, Dong-Geol; Jeong, Seong-Kwan; Kim, Young-Dong

    2015-09-01

    [Purpose] This study investigated the effects of underwater treadmill walking training on the peak torque of the knee in hemiplegic patients. [Subjects and Methods] Thirty-two subjects, who were randomly allocated to an experimental group (n=16) and a control group (n=16), performed underwater treadmill walking training and overground treadmill walking training, respectively, for 30 minutes/session, 3 sessions/week, for 6 weeks. An isokinetic dynamometer was used to assess the peak torque. [Results] The subjects in the experimental group showed an increase in the peak knee extension torque compared to the control group. [Conclusion] The results suggested that underwater treadmill walking training has a greater effect on peak knee extension torque at velocities of 60°/sec and 120°/sec than overground treadmill walking training.

  8. Walking football as sustainable exercise for older adults - A pilot investigation.

    Science.gov (United States)

    Reddy, Peter; Dias, Irundika; Holland, Carol; Campbell, Niyah; Nagar, Iaysha; Connolly, Luke; Krustrup, Peter; Hubball, Harry

    2017-06-01

    The health benefits of playing football and the importance of exercise and social contact for healthy ageing are well established, but few older adults in the UK take enough exercise. Football is popular, flexible in format and draws players into engrossing, effortful and social exercise, but the physical demands of play at full speed may make it unsustainable for some older adults. Restricted to walking pace, will play still be engaging? Will health benefits be retained? Will physical demands remain manageable? This pilot study aims to investigate: (1) the experience of older adults playing walking football every week, is it sustainable and rewarding, (2) the intensity and locomotor pattern of walking football, (3) the scale and nature of walking football health benefits and (4) possible cognitive benefits of playing walking football through measures of processing speed, selective and divided attention and updating and inhibition components of executive function.
 'Walking football' and 'waiting list' groups were compared before and after 12 weeks of one-hour per week football. Walking football was found to be engaging, sustainable for older adults and moderately intensive; however, selective health and cognitive benefits were not found from this brief intervention. Highlights Walking football is a lower impact but authentic form of football that enables older players to extend their active participation. Walking football is enjoyable and moderately demanding and may be a sustainable form of exercise for older adults. Health and cognitive benefits to playing walking football were not found.

  9. Effect of pretesting on intentions and behaviour: a pedometer and walking intervention.

    Science.gov (United States)

    Spence, John C; Burgess, Jenny; Rodgers, Wendy; Murray, Terra

    2009-09-01

    This study addressed the influence of pedometers and a pretest on walking intentions and behaviour. Using a Solomon four-group design, 63 female university students were randomly assigned to one of four conditions: pedometer and pretest (n = 16), pedometer and no pretest (n = 16), no pedometer and pretest (n = 15), no pedometer and no pretest (n = 16). The pretest conditions included questions on walking, intentions to walk 12,500 steps per day, and self-efficacy for walking 12,500 steps per day. In the pedometer conditions a Yamax Digi-Walker SW-650 pedometer was worn for one week. All participants completed posttest questions. While significant pretest x pedometer interactions would have indicated the presence of pretest sensitisation, no such interactions were observed for either intention or self-reported walking. Wearing pedometers reduced intentions for future walking and coping self-efficacy. However, after controlling for pretest self-reported walking, pedometer use resulted in more self-reported walking. We conclude that wearing a pedometer increased self-reported walking behaviour but that a pretest did not differentially influence walking intentions, behaviour, or self-efficacy.

  10. Adjuvant therapy, not mammographic screening, accounts for most of the observed breast cancer specific mortality reductions in Australian women since the national screening program began in 1991.

    Science.gov (United States)

    Burton, Robert C; Bell, Robin J; Thiagarajah, Geetha; Stevenson, Christopher

    2012-02-01

    There has been a 28% reduction in age-standardised breast cancer mortality in Australia since 1991 when the free national mammographic program (BreastScreen) began. Therefore, a comparative study between BreastScreen participation and breast cancer age specific mortality trends in Australia was undertaken for two time periods between 1991 and 2007, where women aged 50-59 and 60-69 years, who were invited to screen, were compared to women aged 40-49 and 70-79 years who were not invited, but who did have access to the program. There were mortality reductions in all four age groups between 1991-1992 and 2007, resulting in 5,849 (95% CI 4,979 to 6,718) fewer women dying of breast cancer than would have otherwise been the case. Women aged 40-49 years, who had the lowest BreastScreen participation (approximately 20%), had the largest mortality reduction: 44% (95% CI 34.8-51.2). Women aged 60-69 years, who had the highest BreastScreen participation (approximately 60%), had the smallest mortality reduction: 19% (95% CI 10.5-26.9). As BreastScreen participation by invited women aged 50-69 years only reached a maximum of about 55-60% in 1998-1999, a decline in mortality in Australian women cannot be attributed to BreastScreen prior to this time. Thus, almost 60% of the Australian decline in breast cancer mortality since 1991 cannot be attributed to BreastScreen. Therefore, mammographic screening cannot account for most of the reductions in breast cancer mortality that have occurred in Australian women since 1991 and may have contributed to over-diagnosis. Most, if not all, of the reductions can be attributed to the adjuvant hormonal and chemotherapy, which Australian women have increasingly received since 1986.

  11. A randomized trial of functional electrical stimulation for walking in incomplete spinal cord injury: Effects on walking competency.

    Science.gov (United States)

    Kapadia, Naaz; Masani, Kei; Catharine Craven, B; Giangregorio, Lora M; Hitzig, Sander L; Richards, Kieva; Popovic, Milos R

    2014-09-01

    Multi-channel surface functional electrical stimulation (FES) for walking has been used to improve voluntary walking and balance in individuals with spinal cord injury (SCI). To investigate short- and long-term benefits of 16 weeks of thrice-weekly FES-assisted walking program, while ambulating on a body weight support treadmill and harness system, versus a non-FES exercise program, on improvements in gait and balance in individuals with chronic incomplete traumatic SCI, in a randomized controlled trial design. Individuals with traumatic and chronic (≥18 months) motor incomplete SCI (level C2 to T12, American Spinal Cord Injury Association Impairment Scale C or D) were recruited from an outpatient SCI rehabilitation hospital, and randomized to FES-assisted walking therapy (intervention group) or aerobic and resistance training program (control group). Outcomes were assessed at baseline, and after 4, 6, and 12 months. Gait, balance, spasticity, and functional measures were collected. Spinal cord independence measure (SCIM) mobility sub-score improved over time in the intervention group compared with the control group (baseline/12 months: 17.27/21.33 vs. 19.09/17.36, respectively). On all other outcome measures the intervention and control groups had similar improvements. Irrespective of group allocation walking speed, endurance, and balance during ambulation all improved upon completion of therapy, and majority of participants retained these gains at long-term follow-ups. Task-oriented training improves walking ability in individuals with incomplete SCI, even in the chronic stage. Further randomized controlled trials, involving a large number of participants are needed, to verify if FES-assisted treadmill training is superior to aerobic and strength training.

  12. FDG-PET imaging of lower extremity muscular activity during level walking

    Energy Technology Data Exchange (ETDEWEB)

    Oi, Naoyuki; Iwaya, Tsutomu; Tobimatsu, Yoshiko; Fujimoto, Toshihiko [Tohoku Univ., Sendai (Japan). Graduate School of Medicine; Itoh, Masatoshi; Yamaguchi, Keiichiro [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

    2003-07-01

    We analyzed muscular activity of the lower extremities during level walking using positron emission tomography (PET) with {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG). We examined 17 healthy male subjects; 11 were assigned to a walking group and 6 to a resting group. After {sup 18}F-FDG injection, the walking group subjects walked at a free speed for 15 min. A whole-body image was then obtained by a PET camera, and the standardized uptake ratio (SUR) was computed for each muscle. The SUR for each muscle of the walking group was compared with that for the corresponding muscles in the resting group. The level of muscular activity of all the muscles we examined were higher during level walking than when resting. The activity of the lower leg muscles was higher than that of the thigh muscles during level walking. The muscular activity of the soleus was highest among all the muscles examined. Among the gluteal muscles, the muscular activity of the gluteus minimus was higher than that of the gluteus maximus and gluteus medius. The concurrent validity of measuring muscular activity of the lower extremity during level walking by the PET method using {sup 18}F-FDG was demonstrated. (author)

  13. Mechanical design of walking machines.

    Science.gov (United States)

    Arikawa, Keisuke; Hirose, Shigeo

    2007-01-15

    The performance of existing actuators, such as electric motors, is very limited, be it power-weight ratio or energy efficiency. In this paper, we discuss the method to design a practical walking machine under this severe constraint with focus on two concepts, the gravitationally decoupled actuation (GDA) and the coupled drive. The GDA decouples the driving system against the gravitational field to suppress generation of negative power and improve energy efficiency. On the other hand, the coupled drive couples the driving system to distribute the output power equally among actuators and maximize the utilization of installed actuator power. First, we depict the GDA and coupled drive in detail. Then, we present actual machines, TITAN-III and VIII, quadruped walking machines designed on the basis of the GDA, and NINJA-I and II, quadruped wall walking machines designed on the basis of the coupled drive. Finally, we discuss walking machines that travel on three-dimensional terrain (3D terrain), which includes the ground, walls and ceiling. Then, we demonstrate with computer simulation that we can selectively leverage GDA and coupled drive by walking posture control.

  14. Walking to the beat of their own drum: how children and adults meet timing constraints.

    Directory of Open Access Journals (Sweden)

    Simone V Gill

    Full Text Available Walking requires adapting to meet task constraints. Between 5- and 7-years old, children's walking approximates adult walking without constraints. To examine how children and adults adapt to meet timing constraints, 57 5- to 7-year olds and 20 adults walked to slow and fast audio metronome paces. Both children and adults modified their walking. However, at the slow pace, children had more trouble matching the metronome compared to adults. The youngest children's walking patterns deviated most from the slow metronome pace, and practice improved their performance. Five-year olds were the only group that did not display carryover effects to the metronome paces. Findings are discussed in relation to what contributes to the development of adaptation in children.

  15. Three-dimensional Motion Analysis of the Ankle during Backward Walking.

    Science.gov (United States)

    Soda, Naoki; Ueki, Tsutomu; Aoki, Takaaki

    2013-06-01

    [Purpose] The purpose of this study was to perform kinematic and kinetic analyses of the ankle during both forward and backward walking using three-dimensional motion analysis. [Subjects] The subjects were 11 healthy adults. [Methods] Measurements of forward and backward walking motions were taken using a three-dimensional motion analysis device and 3 ground reaction force plates. The analysis segment was the standing phase and the items analyzed were walking time, maximum dorsal flexion of the ankle, maximum angle of plantar flexion, peak ankle power in the sagittal plane, workload of the ankle, and work rate. Statistical analysis consisted of comparisons using the t-test for each of the items measured during both forward and backward walking. [Results] The backward walking group had significantly lower ankle power, workload, and work rate. [Conclusion] The propulsive force in backward walking must come from some factor other than the ankle. The analysis of joint power is an important index for understanding the motion.

  16. Walking speed and distance in different environments of subjects in the later stage post-stroke.

    Science.gov (United States)

    Carvalho, Cristiane; Sunnerhagen, Katharina S; Willén, Carin

    2010-11-01

    The purpose of this study is to assess short- and long-distance walking performance in indoor and outdoor environments of slow and fast walkers' subjects living in the community in the later stage post-stroke. Thirty-six subjects with at least 6 months post-stroke were included and divided into two groups based on their walking speed in the clinical setting. Thirty-meter walk tests (30 mWT) at self-selected and maximum speeds were assessed in three environments: (1) clinical setting; (2) basement setting; and (3) outdoor setting. Six-minute walk test (6 MWT) distance was assessed in the clinical and outdoor settings. The differences between the 30 mWT and the 6 MWT, as measured by the actual distance obtained in the 6 MWT and the predicted distance calculated for the 30 mWT, were also investigated. There was no difference in walking speed when subjects performed short-distance walking in different environments. However, a difference was found in performance of long-distance walking. Subjects who walked 0.8 m/s or faster also walked further in the outdoor setting. The findings of our study demonstrate that in those who scored below 0.8 m/s, performance of short- and long-distance walking evaluated in an indoor environment reflects the results obtained in an outdoor environment. However, for subjects post-stroke who score 0.8 m/s or faster, distance was increased in the outdoor environments during long-distance walking. Walking speed obtained over a short distance seemed to overestimate long-distance walking capacity for the slow walkers, despite the environment.

  17. Comparison of bioenergetics of walking during a multistage incremental shuttle walk test and a 6-min walk test in active older adults.

    Science.gov (United States)

    Leone, Mario; Duvergé, Sébastien; Kalinova, Émilia; Bui, Hung Tien; Comtois, Alain S

    2016-03-14

    The goal of the present research was to compare the bioenergetics variability of walking, during the 6-min walk test (6-MWT) and a multistage incremental shuttle walk test (MISWT) in an active older population. Twenty-two healthy physically active older adults with a group mean age of 70.4 ± 5.8 years completed the 6-MWT and the MISWT. Heart rate (HR), walking speed and walking [Formula: see text]O2 were measured throughout each test with a portable metabolic cart. Strong correlations were found for the [Formula: see text]O2 peak and the walking speed (r = 0.91 and r = 0.89 respectively for 6-MWT and MISWT). Differences in [Formula: see text]O2 peak values were analysed with a paired Student's t test. Repeated measures ANOVA were conducted to detect differences between tests. The Bland and Altman plot indicates that the average difference between both tests was 2.5 ml kg(-1) min(-1). MISWT [Formula: see text]O2 peak means were significantly greater than the 6-MWT [Formula: see text]O2 peak mean values (21.6 ± 5.3 vs. 18.9 ± 4.5 ml kg(-1) min(-1)) which indicate bioenergetics differences between the two walking tests. Thus, the MISWT and 6-MWT elicited different walking [Formula: see text]O2 peak and HR suggesting that the MISWT field test challenge the participants to a higher level of cardiovascular and respiratory stress. The walking [Formula: see text]O2 peak recorded for the MISWT was significantly greater than the 6-MWT. Consequently, both tests seem to measure different facets of the aerobic capacity. MISWT seems to be a better indicator of maximal aerobic power whereas the 6-MWT provides more relevant information regarding aerobic endurance in aging population.

  18. Walking through Apertures in Individuals with Stroke

    Science.gov (United States)

    Higuchi, Takahiro

    2017-01-01

    Objective Walking through a narrow aperture requires unique postural configurations, i.e., body rotation in the yaw dimension. Stroke individuals may have difficulty performing the body rotations due to motor paralysis on one side of their body. The present study was therefore designed to investigate how successfully such individuals walk through apertures and how they perform body rotation behavior. Method Stroke fallers (n = 10), stroke non-fallers (n = 13), and healthy controls (n = 23) participated. In the main task, participants walked for 4 m and passed through apertures of various widths (0.9–1.3 times the participant’s shoulder width). Accidental contact with the frame of an aperture and kinematic characteristics at the moment of aperture crossing were measured. Participants also performed a perceptual judgment task to measure the accuracy of their perceived aperture passability. Results and Discussion Stroke fallers made frequent contacts on their paretic side; however, the contacts were not frequent when they penetrated apertures from their paretic side. Stroke fallers and non-fallers rotated their body with multiple steps, rather than a single step, to deal with their motor paralysis. Although the minimum passable width was greater for stroke fallers, the body rotation angle was comparable among groups. This suggests that frequent contact in stroke fallers was due to insufficient body rotation. The fact that there was no significant group difference in the perceived aperture passability suggested that contact occurred mainly due to locomotor factors rather than perceptual factors. Two possible explanations (availability of vision and/or attention) were provided as to why accidental contact on the paretic side did not occur frequently when stroke fallers penetrated the apertures from their paretic side. PMID:28103299

  19. Utilitarian and Recreational Walking Among Spanish- and English-Speaking Latino Adults in Micropolitan US Towns.

    Science.gov (United States)

    Doescher, Mark P; Lee, Chanam; Saelens, Brian E; Lee, Chunkuen; Berke, Ethan M; Adachi-Mejia, Anna M; Patterson, Davis G; Moudon, Anne Vernez

    2017-04-01

    Walking among Latinos in US Micropolitan towns may vary by language spoken. In 2011-2012, we collected telephone survey and built environment (BE) data from adults in six towns located within micropolitan counties from two states with sizable Latino populations. We performed mixed-effects logistic regression modeling to examine relationships between ethnicity-language group [Spanish-speaking Latinos (SSLs); English-speaking Latinos (ESLs); and English-speaking non-Latinos (ENLs)] and utilitarian walking and recreational walking, accounting for socio-demographic, lifestyle and BE characteristics. Low-income SSLs reported higher amounts of utilitarian walking than ENLs (p = 0.007), but utilitarian walking in this group decreased as income increased. SSLs reported lower amounts of recreational walking than ENLs (p = 0.004). ESL-ENL differences were not significant. We identified no statistically significant interactions between ethnicity-language group and BE characteristics. Approaches to increase walking in micropolitan towns with sizable SSL populations may need to account for this group's differences in walking behaviors.

  20. The Politics of Walking: Rural Women Encounters with Space and Memoir

    NARCIS (Netherlands)

    Ibáñez Martín, R.

    2016-01-01

    A group of elderly and retired women from a northern village in Spain (they call themselves las chicas, the girls), try gather every week to take a walk together. Assembling my ethnographic notes, I describe the walk and offer an analytical foray into the following questions: What can we learn about

  1. Self-interacting random walks

    CERN Document Server

    Peres, Yuval; Sousi, Perla

    2012-01-01

    Let $\\mu_1,... \\mu_k$ be $d$-dimensional probability measures in $\\R^d$ with mean 0. At each step we choose one of the measures based on the history of the process and take a step according to that measure. We give conditions for transience of such processes and also construct examples of recurrent processes of this type. In particular, in dimension 3 we give the complete picture: every walk generated by two measures is transient and there exists a recurrent walk generated by three measures.

  2. Pedagogies of the Walking Dead

    Directory of Open Access Journals (Sweden)

    Michael A. Peters

    2016-04-01

    Full Text Available This paper investigates the trope of the zombie and the recent upsurge in popular culture surrounding the figure of the zombie described as the “walking dead”. We investigate this trope and figure as a means of analyzing the “pedagogy of the walking dead” with particular attention to the crisis of education in the era of neoliberal capitalism. In particular we examine the professionalization and responsibilization of teachers in the new regulative environment and ask whether there is any room left for the project of critical education.

  3. Age-related differences in walking stability

    National Research Council Canada - National Science Library

    Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C

    2003-01-01

    .... to evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing...

  4. Brisk Walk May Help Sidestep Heart Disease

    Science.gov (United States)

    ... fullstory_162978.html Brisk Walk May Help Sidestep Heart Disease In just 10 weeks, cholesterol, blood pressure and ... at moderate intensity may lower the risk of heart disease, a small study suggests. "We know walking is ...

  5. Minnesota Walk-In Access Sites

    Data.gov (United States)

    Minnesota Department of Natural Resources — The Minnesota Walk-In Access site (WIA) GIS data represents areas of private land that have been made open to the public for the purpose of walk-in (foot travel)...

  6. Walking Shoes: Features and Fit

    Science.gov (United States)

    ... be snug, not tight. If you're a woman with wide feet, consider men's or boys' shoes, which are cut a bit larger through the heel and the ball of the foot. Walk in the shoes before buying them. They should feel comfortable right away. Make sure your heel fits snugly in ...

  7. Walking Tips for Older Adults

    Science.gov (United States)

    ... the most ppular form of exercise among older adults and it's a great choice. What can walking do for you? strengthen muscles help prevent weight gain lower risks of heart disease, stroke, diabetes, and osteoporosis improve balance lower the likelihood of falling If ...

  8. Chronic venous disorders and injection drug use: impact on balance, gait, and walk speed.

    Science.gov (United States)

    Pieper, Barbara; Templin, Thomas N; Birk, Thomas J; Kirsner, Robert S

    2008-01-01

    Injection drug users are at high risk for chronic venous disorders (CVD), a condition resulting in a progressive deterioration of venous function of the legs. However, the effects of CVD on walking mobility in this population have not been studied. We examined a causal model of the relationship between injection drug use, CVD, and Walking Mobility. The validity of the Tinetti Balance and Gait scales and walk speed as a composite measure of Walking Mobility was also explored. The participants were 104 men and women from a methadone maintenance treatment center. Drug use included 18 persons who injected drugs only in the hands, arms, and above the waist; 70 who injected all over the body including the lower extremities; and 16 who never injected drugs but used illegal substances by other routes. Forty-nine percent of participants had moderate to severe CVD. Participants were classified into 2 groups according to their history of injection drug use: (a) those who injected in the lower extremities (n = 70) and (b) those who injected in the arms plus those who did not inject (n = 34). All measurements were obtained at baseline and again approximately 6.5 weeks later. Structural equation modeling was used to examine the causal effect of CVD on Walking Mobility. The validity of the Balance and Gait scales and the walk time variable as measures of a Walking Mobility factor was examined using a second-order confirmatory factor analysis. Questionnaires included the Demographic and Health History and Drug History. The lower extremities were evaluated with the clinical portion of the Clinical-Etiology-Anatomy-Pathophysiology classification. Participants completed the Tinetti Balance and Gait test. A timed 6-m walk at the person's normal pace was used to calculate walk speed. Test-retest reliability of the Tinetti Balance and Gait test and walk speed ranged from 0.79 to 0.86. Balance and gait scores were skewed toward the high end of the scale. Walking speed was slow. The leg

  9. Efficient quantum walk on a quantum processor

    OpenAIRE

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiao-Qi; O'Brien, Jeremy; Wang, Jingbo; Matthews, Jonathan

    2016-01-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise quantum walks have shown much potential as a frame- work for developing new quantum algorithms. In this paper, we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs ef...

  10. Einstein's random walk and thermal diffusion

    OpenAIRE

    2013-01-01

    Thermal diffusion has been studied for over 150 years. Despite of the long history and the increasing importance of the phenomenon, the physics of thermal diffusion remains poorly understood. In this paper Ludwig's thermal diffusion is explained using Einstein's random walk. The only new structure added is the spatial heterogeneity of the random walk to reflect the temperature gradient of thermal diffusion. Hence, the walk length and the walk speed are location dependent functions in this pap...

  11. Walking pattern classification and walking distance estimation algorithms using gait phase information.

    Science.gov (United States)

    Wang, Jeen-Shing; Lin, Che-Wei; Yang, Ya-Ting C; Ho, Yu-Jen

    2012-10-01

    This paper presents a walking pattern classification and a walking distance estimation algorithm using gait phase information. A gait phase information retrieval algorithm was developed to analyze the duration of the phases in a gait cycle (i.e., stance, push-off, swing, and heel-strike phases). Based on the gait phase information, a decision tree based on the relations between gait phases was constructed for classifying three different walking patterns (level walking, walking upstairs, and walking downstairs). Gait phase information was also used for developing a walking distance estimation algorithm. The walking distance estimation algorithm consists of the processes of step count and step length estimation. The proposed walking pattern classification and walking distance estimation algorithm have been validated by a series of experiments. The accuracy of the proposed walking pattern classification was 98.87%, 95.45%, and 95.00% for level walking, walking upstairs, and walking downstairs, respectively. The accuracy of the proposed walking distance estimation algorithm was 96.42% over a walking distance.

  12. Walking the HMO balance.

    Science.gov (United States)

    Gallagher, S M

    2001-03-01

    Fidelity is the ethical obligation to act in good faith to keep promises, fulfill agreements, and maintain relationships and fiduciary responsibilities. Consumers are increasingly interested in the balance between the fiscal viability of our current healthcare delivery system and the system's reason for existence--that is, to serve the health needs of clients. Escalating healthcare costs have driven many institutions and third party payors to examine service and payment practices. Some consumers and consumer rights groups contend that these evolving practices threaten the very essence of health and healthcare. The ethical obligation of fidelity, especially as it relates to the business model of healthcare, is examined. Threats to fidelity are reviewed, and the response to these threats by one consumer rights group is presented. A case study is included.

  13. Developmental Continuity? Crawling, Cruising, and Walking

    Science.gov (United States)

    Adolph, Karen E.; Berger, Sarah E.; Leo, Andrew J.

    2011-01-01

    This research examined developmental continuity between "cruising" (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior…

  14. Claimed walking distance of lower limb amputees

    NARCIS (Netherlands)

    Geertzen, JHB; Bosmans, JC; Van der Schans, CP; Dijkstra, PU

    2005-01-01

    Purpose: Walking ability in general and specifically for lower limb amputees is of major importance for social mobility and ADL independence. Walking determines prosthesis prescription. The aim of this study was to mathematically analyse factors influencing claimed walking distance of lower limb amp

  15. Comparison of Estimated and Measured Muscle Activity During Inclined Walking.

    Science.gov (United States)

    Alexander, Nathalie; Schwameder, Hermann

    2016-04-01

    While inclined walking is a frequent daily activity, muscle forces during this activity have rarely been examined. Musculoskeletal models are commonly used to estimate internal forces in healthy populations, but these require a priori validation. The aim of this study was to compare estimated muscle activity using a musculoskeletal model with measured EMG data during inclined walking. Ten healthy male participants walked at different inclinations of 0°, ± 6°, ± 12°, and ± 18° on a ramp equipped with 2 force plates. Kinematics, kinetics, and muscle activity of the musculus (m.) biceps femoris, m. rectus femoris, m. vastus lateralis, m. tibialis anterior, and m. gastrocnemius lateralis were recorded. Agreement between estimated and measured muscle activity was determined via correlation coefficients, mean absolute errors, and trend analysis. Correlation coefficients between estimated and measured muscle activity for approximately 69% of the conditions were above 0.7. Mean absolute errors were rather high with only approximately 38% being ≤ 30%. Trend analysis revealed similar estimated and measured muscle activities for all muscles and tasks (uphill and downhill walking), except m. tibialis anterior during uphill walking. This model can be used for further analysis in similar groups of participants.

  16. World Cup: Brands Gamble Began

    Institute of Scientific and Technical Information of China (English)

    Wang Ting

    2010-01-01

    @@ Among the 32 national teams,there are only seven sports brands sponsors.Of them,the famous three sports brands Nike,Adidas and Puma gather together the sponsorship with 28 teams in total.Each brand features themselves with technology innovation or branding promotion strategy.

  17. How newspapers began to blog

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis

    2012-01-01

    In this article, I examine how ‘old’ media organizations develop ‘new’ media technologies by analyzing processes of technological innovation in two Danish newspaper companies that integrated blogs into their websites in very different ways in 2007. Drawing on concepts from science and technology...... blogging ought to be in each organization and tried to shape the technology and pull the development work in different directions. On the basis of interviews with key participants, I show how the two newspaper organizations (equally ‘old’ media) came to develop nominally the same ‘new’ medium (blogs...

  18. ONGULUMBASHE: WHERE THE BUSHWAR BEGAN

    African Journals Online (AJOL)

    hennie

    intervention in the Angolan civil war in 1975/76 and subsequently served in the ... Having said all this, the book was obviously not written for a scholarly audience ... Lt Col (Prof) Deon Visser, Department of Military History, Faculty of Military.

  19. Are kinematics of the walk related to the locomotion of a warmblood horse at the trot?

    Science.gov (United States)

    Back, W; Schamhardt, H C; Barneveld, A

    1996-10-01

    Summary In purchase examinations or at studbook selection sales the locomotor apparatus of horses is judged both at walk and trot. To evaluate whether kinematics of the walk are related to the locomotion at the trot, fore and hind limb movements of a group of 24 26-month-old warmbloods were recorded at walk and trot on a treadmill (1.6 and 4 m/s) using a modified CODA-3 gait analysis system. The intralimb coordination patterns at walk and trot were compared, and temporal and spatial variables of these gaits were related. Stride and stance durations (s) were shorter at the trot, while the stance distance (m) and swing duration (s) remained the same. Moreover, the pattern of the joint angle-time curves at walk and trot looked rather similar, though shifted to the left at trot because of the shorter relative stance duration. During the stance phase, the shoulder, stifle and tarsal joints were more flexed throughout, while the carpal and fetlock joints were more maximally extended in the trot than in the walk. In the swing phase, the elbow, carpal, stifle, and tarsal joints were more flexed because of the higher 'operating' speed at the trot compared to the walk. All other kinematic variables at the trot could be predicted from the mean ± 1sd of the values recorded at the walk. Moreover, nearly all kinematic variables at the walk correlated well with those at the trot, while variables indicating gait quality of the walk were similar to the ones identified previously for the trot. In conclusion, kinematics recorded at the walk in a group of horses were similar to and thus predictive for locomotion at the trot providing the decreased stance duration and the increased speed of the trot are taken into consideration.

  20. Active quantum walks: a framework for quantum walks with adiabatic quantum evolution

    Science.gov (United States)

    Wu, Nan; Song, Fangmin; Li, Xiangdong

    2016-05-01

    We study a new methodology for quantum walk based algorithms. Different from the passive quantum walk, in which a walker is guided by a quantum walk procedure, the new framework that we developed allows the walker to move by an adiabatic procedure of quantum evolution, as an active way. The use of this active quantum walk is helpful to develop new quantum walk based searching and optimization algorithms.

  1. Low-Volume Walking Program Improves Cardiovascular-Related Health in Older Adults

    Directory of Open Access Journals (Sweden)

    Jong-Hwan Park, Masashi Miyashita

    2014-09-01

    Full Text Available Although numerous sources of evidence show that regular physical activity is beneficial to health, most individuals do not engage in a sufficient amount of physical activity to meet the guidelines set out by expert panels. In addition, the minimum amount of physical activity associated with reduced cardiovascular disease risk markers is not clear in older adults. The purpose of this study was to determine the effects of a 12-week walking program involving an exercise volume below the current minimum physical activity recommendation on cardiovascular disease risk markers in older adults. The participants were recruited from the following two groups separately: a walking group (n = 14 and a control group (n = 14. In the walking group, participants walked 30 to 60 minutes per session on 2 days per week for 12 weeks (average walking time, 49.4 ± 8.8 min/session. Plasma oxidised low-density lipoprotein concentrations tended to be lower than baseline values in the walking group after 12 weeks (paired t-test, p = 0.127. The ratio of oxidised low-density lipoprotein to high-density lipoprotein cholesterol was significantly lower than the baseline ratio in the walking group after 12 weeks (paired t-test, p = 0.035. Resting systolic blood pressure and diastolic blood pressure were significantly lower than baseline values in the walking group after 12 weeks (paired t-tests, p = 0.002, p < 0.0005, respectively. Our findings demonstrate that a 12-week walking program comprising a low volume of physical activity confers a benefit to cardiovascular-related health in older adults.

  2. Virtual Reality Training with Cognitive Load Improves Walking Function in Chronic Stroke Patients.

    Science.gov (United States)

    Cho, Ki Hun; Kim, Min Kyu; Lee, Hwang-Jae; Lee, Wan Hee

    2015-01-01

    Virtual reality training is considered as an effective intervention method of stroke patients, and the virtual reality system for therapeutic rehabilitation has emphasized the cognitive factors to improve walking function. The purpose of current study was to investigate the effect of virtual reality training with cognitive load (VRTCL) on walking function of chronic stroke. Chronic stroke patients were randomly assigned to the VRTCL group (11 patients, including 5 men; mean age, 60.0 years; post-stroke duration, 273.9 days) or control group (11 patients, including 2 men; mean age, 58.6 years; post-stroke duration, 263.9 days). All subjects participated in the standard rehabilitation program that consisted of physical and occupational therapies. In addition, VRTCL group participated in the VRTCL for 4 weeks (30 min per day and five times a week), while those in the control group participated in virtual reality treadmill training. Walking function under single (walking alone) and dual task (walking with cognitive tasks) conditions was assessed using an electrical walkway system. After the 4-week intervention, under both single and dual task conditions, significant improvement on walking function was observed in VRTCL and control groups (P < 0.05). In addition, in the dual task condition, greater improvement on walking function was observed in the VRTCL group, compared with the control group (P < 0.05). These findings demonstrated the efficacy of VRTCL on the walking function under the dual task condition. Therefore, we suggest that VRTCL may be an effective method for the achievement of independent walking in chronic stroke patients.

  3. Walking...A Step in the Right Direction!

    Science.gov (United States)

    ... parts: Warm up by walking slowly. Increase your speed to a brisk walk. Brisk walking means walking fast enough to raise your heart ... go faster and farther. Add hills or some stairs to make your walks more challenging. Review the sample walking plan that follows for an idea of how ...

  4. Patient Safety Leadership WalkRounds at Partners Healthcare: learning from implementation.

    Science.gov (United States)

    Frankel, Allan; Grillo, Sarah Pratt; Baker, Erin Graydon; Huber, Camilla Neppl; Abookire, Susan; Grenham, Marianne; Console, Pam; O'Quinn, Mary; Thibault, George; Gandhi, Tejal K

    2005-08-01

    Brigham and Women's Hospital (BWH) began Patient Safety Leadership WalkRounds in January 2001; its experience, along with that of three other Partner Healthcare hospitals, is reported. COLLECTING DATA ON WALKROUNDS: Data were obtained from interviews with patient safety personnel, WalkRounds scribes, and senior leaders. A total of 233 one-hour WalkRounds during 28 months yielded 1,433 comments--30% related to equipment, 13% to communications, 7% to pharmacy, and 6% to workforce. Actions occurred quickly in small hospitals. Formal processes for managing larger issues were necessary in large organizations. Implementation feasibility featured more prominently than severity in determining actions. The study generated essential guidelines for success--for example, the supporting resources must include the maintenance of effective information databases that identify actions taken, and the discussions during WalkRounds are influenced by who in leadership is participating, their ability to quietly listen, and whether they have clinical or nonclinical backgrounds. WalkRounds appears to be an effective tool for engaging leadership, identifying safety issues, and supporting a culture of safety.

  5. Falling while walking: A hidden contributor to pedestrian injury.

    Science.gov (United States)

    Oxley, Jennifer; O'Hern, Steve; Burtt, Duane; Rossiter, Ben

    2017-02-07

    Walking is a sustainable mode of transportation which is beneficial to both individuals and to the broader community, however, there are risks and it is essential that road design and operation provides safe conditions for walking. In Victoria, pedestrians represent one of the most vulnerable road user groups, accounting for approximately 12% of all road fatalities and serious injuries. These figures largely represent injuries where the pedestrian has been struck by a vehicle with the extent of pedestrian-only injuries largely un-reported. Falling while walking may be a significant contributor to pedestrian only injuries. Indeed, the World Health Organisation has identified falls generally as the second leading cause of unintentional injury death in older populations. Despite the prevalence of fall-related injuries, there has been relatively little research undertaken to address the issues surrounding falls that occur while walking for transport and in public spaces. This study, therefore, aimed to address this gap in our knowledge. Analyses of various data sources were undertaken to enhance our understanding of fall-related injuries while walking in Victoria. Two sources of data were accessed: Only 85 fall-related incidents were reported in the crash-based data, however, pedestrian falls while walking in the road environment accounted for an average of 1680 hospital admissions and 3545 emergency department presentations each year, and this number is rising. The findings in this study show clearly that Police data is of little use when attempting to understand issues of safe travel for pedestrians other than vehicle-pedestrian incidents. However, analysis of hospital data provides a more realistic indication of the extent of pedestrian fall-related injuries and highlights the significant number of pedestrian fall-related injuries that occur each year. Moreover, the findings identified that older pedestrians are significantly over-represented amongst fall

  6. Foot pressure distribution during walking in young and old adults

    Directory of Open Access Journals (Sweden)

    Lipsitz Lewis A

    2005-05-01

    Full Text Available Abstract Background Measurement of foot pressure distribution (FPD is clinically useful for evaluation of foot and gait pathologies. The effects of healthy aging on FPD during walking are not well known. This study evaluated FPD during normal walking in healthy young and elderly subjects. Methods We studied 9 young (30 ± 5.2 years, and 6 elderly subjects (68.7 ± 4.8 years. FPD was measured during normal walking speed using shoe insoles with 99 capacitive sensors. Measured parameters included gait phase characteristics, mean and maximum pressure and force, and relative load. Time-series measurements of each variable for all sensors were grouped into 9 anatomical masks. Results Elderly subjects had lower normalized maximum pressure for the medial and lateral calcaneal masks, and for all medial masks combined. In the medial calcaneus mask, the elderly group also had a lower absolute maximum and lower mean and normalized mean pressures and forces, compared to young subjects. Elderly subjects had lower maximum force and normalized maximum force and lower mean force and normalized mean forces in the medial masks as well. Conclusion FPD differences between the young and elderly groups were confined to the calcaneus and hallux regions and to the medial side of the foot. In elderly subjects, weight bearing on the lateral side of the foot during heel touch and toe-off phases may affect stability during walking.

  7. Physiological Cost Index and Comfort Walking Speed in Two Level Lower Limb Amputees Having No Vascular Disease

    Science.gov (United States)

    Vllasolli, Teuta Osmani; Orovcanec, Nikola; Zafirova, Beti; Krasniqi, Blerim; Murtezani, Ardiana; Krasniqi, Valbona; Rama, Bukurije

    2015-01-01

    Background: The Physiological Cost Index (PCI) was introduced by MacGregor to estimate the energy cost in walking of healthy people, also it has been reported for persons with lower limb amputation, walking with prosthesis. Objective: To assess energy cost and walking speed in two level lower limb amputation: transfemoral and transtibial amputation and to determine if the age and prosthetic walking supported with walking aids have impact on energy cost and walking speed. Methods: A prospective cross sectional study was performed in two level lower limb amputees with no vascular disease who were rehabilitated at the Department of Prosthetics and Orthotics at the University Clinical Center of Kosovo. The Physiological Cost Index (PCI) was assessed by five minutes of continuous indoor walking at Comfort Walking Speed (CWS). Results: Eighty three lower limb amputees were recruited. It is shown relevant impact of level of amputation in PCI (t=6.8, pamputation. Conclusions: Walking with transfemoral prosthesis or using walking aids during prosthetic ambulation is matched with higher cost of energy and slower walking speed. Advanced age was shown with high impact on PCI and CWS in both groups of amputees. PMID:25870485

  8. The effects of pregnancy spacing on infant and child mortality in Matlab, Bangladesh: how they vary by the type of pregnancy outcome that began the interval.

    Science.gov (United States)

    DaVanzo, Julie; Hale, Lauren; Razzaque, Abdur; Rahman, Mizanur

    2008-07-01

    Using high-quality longitudinal data on 125,720 singleton live births in Matlab, Bangladesh, we assessed the effects of duration of intervals between pregnancy outcomes on infant and child mortality and how these effects vary over subperiods of infancy and childhood and by the type of outcome that began the interval. Controlling for other correlates of infant and child mortality, we find that shorter intervals are associated with higher mortality. Interval effects are greater if the interval began with a live birth than with another pregnancy outcome. In the first week of the child's life, the effects of short intervals are greater if the sibling born at the beginning of the interval died; after the first month, the effects are greater if that sibling was still alive. Many relationships found are consistent with the maternal depletion hypothesis, and some with sibling competition. Some appear to be due to correlated risks among births to the same mother.

  9. Disaggregate land uses and walking.

    Science.gov (United States)

    McConville, Megan E; Rodríguez, Daniel A; Clifton, Kelly; Cho, Gihyoug; Fleischhacker, Sheila

    2011-01-01

    Although researchers have explored associations between mixed-use development and physical activity, few have examined the influence of specific land uses. This study analyzes how the accessibility, intensity, and diversity of nonresidential land uses are related to walking for transportation. Multinomial logistic regression was used to investigate associations between walking for transportation and neighborhood land uses in a choice-based sample of individuals (n=260) in Montgomery County MD. Land uses examined included banks, bus stops, fast-food restaurants, grocery stores, libraries, rail stations, offices, parks, recreation centers, non-fast-food restaurants, retail, schools, sports facilities, night uses, physical activity uses, and social uses. Exposure to these uses was measured as the street distance from participants' homes to the closest instance of each land use (accessibility); the number of instances of each land use (intensity); and the number of different land uses (diversity). Data were collected from 2004-2006 and analyzed in 2009-2010. After adjusting for individual-level characteristics, the distances to banks, bus stops, fast-food restaurants, grocery stores, rail stations, physical activity uses, recreational facilities, restaurants, social uses and sports facilities were associated negatively with transportation walking (ORs [95% CI] range from 0.01 [0.001, 0.11] to 0.91 [0.85, 0.97]). The intensities of bus stops, grocery stores, offices, and retail stores in participants' neighborhoods were associated positively with transportation walking (ORs [95% CI] range from 1.05 [1.01, 1.08] to 5.42 [1.73, 17.01]). Land-use diversity also was associated positively with walking for transportation (ORs [95% CI] range from 1.39 [1.20, 1.59] to 1.69 [1.30, 2.20]). The accessibility and intensity of certain nonresidential land uses, along with land-use diversity, are positively associated with walking for transportation. A careful mix of land uses in a

  10. Hypotensive response after water-walking and land-walking exercise sessions in healthy trained and untrained women

    Directory of Open Access Journals (Sweden)

    Bocalini DS

    2011-08-01

    Full Text Available Daniel Rodriguez1, Valter Silva2, Jonato Prestes3, Roberta Luksevicius Rica4, Andrey Jorge Serra5, Danilo Sales Bocalini6, Francisco Luciano Pontes Junior71São Judas Tadeu University, São Paulo, SP, Brazil; 2College of Physical Education of Sorocaba, Sorocaba, SP, Brazil; 3Graduation Program in Physical Education, Catholic University of Brasilia, Brasilia-DF, Brazil; 4Department of Physical Education, Arbos College, São Bernardo do Campo, SP, Brazil; 5Department of Physical Education and Laboratory of Rehabilitation Science, Nove de Julho University, São Paulo, SP, Brazil; 6Department of Medicine, Federal University of São Paulo – Escola Paulista de Medicina, São Paulo, SP, Brazil; 7School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, SP, BrazilBackground: The aim of this study was to compare post-exercise hypotension after acute sessions of water-walking and land-walking in healthy trained and untrained women.Methods: Twenty-three untrained (n = 12 and trained (n = 11 normotensive women performed two walking sessions in water and on land at 40% of peak VO2 for 45 minutes. Systolic and diastolic blood pressure and mean arterial pressure were measured 15, 30, 45, and 60 minutes after the exercise sessions.Results: No differences were found between the groups for age and anthropometric parameters, but peak VO2 for the trained women (45 ± 8 mL/kg/minute was higher than for the untrained women (31 ± 3 mL/kg/minute. No differences were found between the groups with regard to systolic and diastolic blood pressure and mean arterial pressure after water immersion. The heart rate in the trained group (62 ± 3 beats per minute [bpm] was significantly lower (P < 0.05 than in the untrained group (72 ± 4 bpm on land, and after water immersion, this difference disappeared (58 ± 5 bpm in the trained women and 66 ± 5 bpm in the untrained women. Sixty minutes after water-walking, systolic blood pressure (108 ± 8 mmHg vs

  11. Biased random walks on multiplex networks

    CERN Document Server

    Battiston, Federico; Latora, Vito

    2015-01-01

    Biased random walks on complex networks are a particular type of walks whose motion is biased on properties of the destination node, such as its degree. In recent years they have been exploited to design efficient strategies to explore a network, for instance by constructing maximally mixing trajectories or by sampling homogeneously the nodes. In multiplex networks, the nodes are related through different types of links (layers or communication channels), and the presence of connections at different layers multiplies the number of possible paths in the graph. In this work we introduce biased random walks on multiplex networks and provide analytical solutions for their long-term properties such as the stationary distribution and the entropy rate. We focus on degree-biased walks and distinguish between two subclasses of random walks: extensive biased walks consider the properties of each node separately at each layer, intensive biased walks deal instead with intrinsically multiplex variables. We study the effec...

  12. High on Walking : Conquering Everyday Life.

    Science.gov (United States)

    Martinsen, Bente; Haahr, Anita; Dreyer, Pia; Norlyk, Annelise

    2017-01-01

    The aim of this study is to discuss the meaning of walking impairment among people who have previously been able to walk on their own. The study is based on findings from three different life situations: older people recovering after admission in intermediate care, people who have lost a leg, and people who live with Parkinson's disease. The analysis of the data is inspired by Paul Ricoeur's philosophy of interpretation. Four themes were identified: (a) I feel high in two ways; (b) Walking has to be automatic; (c) Every Monday, I walk with the girls in the park; and (d) I dream of walking along the street without sticks and things like that. The findings demonstrate that inability to walk profoundly affected the participants' lives. Other problems seemed small by comparison because walking impairment was at the same time experienced as a concrete physical limit and an existential deficit.

  13. Displacement policy favoring the walk in the towns. Actions of european towns; Politiques de deplacement favorisant la marche a pied en ville. Actions de villes europeenne

    Energy Technology Data Exchange (ETDEWEB)

    Vallar, J.P.; Wagenaar, D.

    2003-07-01

    Many towns in Europe began policies favoring the walk. By an evaluation of the actions realized, this study presents the results in four main topics: the planning, the organization, the communication and public information, the evaluation of the initiatives and the perspectives. (A.L.B.)

  14. City Walks and Tactile Experience

    Directory of Open Access Journals (Sweden)

    Mădălina Diaconu

    2011-01-01

    Full Text Available This paper is an attempt to develop categories of the pedestrian’s tactile and kinaesthetic experience of the city. The beginning emphasizes the haptic qualities of surfaces and textures, which can be “palpated” visually or experienced by walking. Also the lived city is three-dimensional; its corporeal depth is discussed here in relation to the invisible sewers, protuberant profiles, and the formal diversity of roofscapes. A central role is ascribed in the present analysis to the formal similarities between the representation of the city by walking through it and the representation of the tactile form of objects. Additional aspects of the “tactile” experience of the city in a broad sense concern the feeling of their rhythms and the exposure to weather conditions. Finally, several aspects of contingency converge in the visible age of architectural works, which record traces of individual and collective histories.

  15. Random walk near the surface

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1988-07-01

    The random walk of a particle on a three-dimensional semi-infinite lattice is considered. In order to study the effect of the surface on the random walk, it is assumed that the velocity of the particle depends on the distance to the surface. Moreover it is assumed that at any point the particle may be absorbed with a certain probability. The probability of the return of the particle to the starting point and the average time of eventual return are calculated. The dependence of these quantities on the distance to the surface, the probability of absorption and the properties of the surface is discussed. The method of generating functions is used.

  16. Quantum walk on a cylinder

    CERN Document Server

    Bru, Luis A; Di Molfetta, Giuseppe; Pérez, Armando; Roldán, Eugenio; Silva, Fernando

    2016-01-01

    We consider the 2D alternate quantum walk on a cylinder. We concentrate on the study of the motion along the open dimension, in the spirit of looking at the closed coordinate as a small or "hidden" extra dimension. If one starts from localized initial conditions on the lattice, the dynamics of the quantum walk that is obtained after tracing out the small dimension shows the contribution of several components, which can be understood from the study of the dispersion relations for this problem. In fact, these components originate from the contribution of the possible values of the quasi-momentum in the closed dimension. In the continuous space-time limit, the different components manifest as a set of Dirac equations, with each quasi-momentum providing the value of the corresponding mass. We briefly discuss the possible link of these ideas to the simulation of high energy physical theories that include extra dimensions.

  17. Ground-based walking training improves quality of life and exercise capacity in COPD.

    Science.gov (United States)

    Wootton, Sally L; Ng, L W Cindy; McKeough, Zoe J; Jenkins, Sue; Hill, Kylie; Eastwood, Peter R; Hillman, David R; Cecins, Nola; Spencer, Lissa M; Jenkins, Christine; Alison, Jennifer A

    2014-10-01

    This study was designed to determine the effect of ground-based walking training on health-related quality of life and exercise capacity in people with chronic obstructive pulmonary disease (COPD). People with COPD were randomised to either a walking group that received supervised, ground-based walking training two to three times a week for 8-10 weeks, or a control group that received usual medical care and did not participate in exercise training. 130 out of 143 participants (mean±sd age 69±8 years, forced expiratory volume in 1 s 43±15% predicted) completed the study. Compared to the control group, the walking group demonstrated greater improvements in the St George's Respiratory Questionnaire total score (mean difference -6 points (95% CI -10- -2), pimproves quality of life and endurance exercise capacity in people with COPD.

  18. Walking to work in Canada: health benefits, socio-economic characteristics and urban-regional variations

    Directory of Open Access Journals (Sweden)

    Williams Allison

    2011-04-01

    Full Text Available Abstract Background There is mounting concern over increasing rates of physical inactivity and overweight/obesity among children and adult in Canada. There is a clear link between the amount of walking a person does and his or her health. The purpose of this paper is to assess the health factors, socio-economic characteristics and urban-regional variations of walking to work among adults in Canada. Methods Data is drawn from two cycles of the Canadian Community Health Survey: 2001 and 2005. The study population is divided into three groups: non-walkers, lower-duration walkers and high-duration walkers. Logistic regression modeling tests the association between levels of walking and health related outcomes (diabetes, high blood pressure, stress, BMI, physical activity, socio-economic characteristics (sex, age, income, education and place of residence (selected Census Metropolitan Areas. Results In 2005, the presence of diabetes and high blood pressure was not associated with any form of walking. Adults within the normal weight range were more likely to be high-duration walkers. Females and younger people were more likely to be lower-duration walkers but less likely to be high-duration walkers. There was a strong association between SES (particularly relative disadvantage and walking to work. In both 2001 and 2005, the conditions influencing walking to work were especially prevalent in Canada's largest city, Toronto, as well as in several small to medium sized urban areas including Halifax, Kingston, Hamilton, Regina, Calgary and Victoria. Conclusion A number of strategies can be followed to increase levels of walking in Canada. It is clear that for many people walking to work is not possible. However, strategies can be developed to encourage adults to incorporate walking into their daily work and commuting routines. These include mass transit walking and workplace walking programs.

  19. Effect of Tai Chi versus Walking on Oxidative Stress in Mexican Older Adults

    Directory of Open Access Journals (Sweden)

    Juana Rosado-Pérez

    2013-01-01

    Full Text Available It has recently been reported that the practice of Tai Chi reduces oxidative stress (OxS, but it is not clear whether walking or Tai Chi produces a greater antioxidant effect. The aim of the present study was to evaluate the effect of the practice of Tai Chi and walking on markers for OxS. We carried out a quasi-experimental study with 106 older adults between 60 and 74 years of age who were clinically healthy and divided into the following groups: (i control group (n=23, (ii walking group (n=43, and (iii Tai Chi group (n=31. We measured the levels of lipoperoxides (LPO, antioxidant enzymes superoxide dismutase (SOD and glutathione peroxidase (GPx, and total antioxidant status (TAS pre- and post-intervention in all subjects. The data were subjected to a covariant analysis. We found lower levels of LPO in the Tai Chi group compared with the walking group (Tai Chi, 0.261 ± 0.02; walking, 0.331 ± 0.02; control, 0.304 ± 0.023 µmol/L; P=0.05. Likewise, we observed significantly higher SOD activity and lower OxS-score in the Tai Chi group (P<0.05. Our findings suggest that the practice of Tai Chi produces a more effective antioxidant effect than walking.

  20. Effect of Tai Chi versus walking on oxidative stress in Mexican older adults.

    Science.gov (United States)

    Rosado-Pérez, Juana; Ortiz, Rocío; Santiago-Osorio, Edelmiro; Mendoza-Núñez, Víctor Manuel

    2013-01-01

    It has recently been reported that the practice of Tai Chi reduces oxidative stress (OxS), but it is not clear whether walking or Tai Chi produces a greater antioxidant effect. The aim of the present study was to evaluate the effect of the practice of Tai Chi and walking on markers for OxS. We carried out a quasi-experimental study with 106 older adults between 60 and 74 years of age who were clinically healthy and divided into the following groups: (i) control group (n = 23), (ii) walking group (n = 43), and (iii) Tai Chi group (n = 31). We measured the levels of lipoperoxides (LPO), antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total antioxidant status (TAS) pre- and post-intervention in all subjects. The data were subjected to a covariant analysis. We found lower levels of LPO in the Tai Chi group compared with the walking group (Tai Chi, 0.261 ± 0.02; walking, 0.331 ± 0.02; control, 0.304 ± 0.023 µmol/L; P = 0.05). Likewise, we observed significantly higher SOD activity and lower OxS-score in the Tai Chi group (P Tai Chi produces a more effective antioxidant effect than walking.

  1. Segment lengths influence hill walking strategies.

    Science.gov (United States)

    Sheehan, Riley C; Gottschall, Jinger S

    2014-08-22

    Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking.

  2. Kinematics and kinetics during walking in individuals with gluteal tendinopathy.

    Science.gov (United States)

    Allison, Kim; Wrigley, Tim V; Vicenzino, Bill; Bennell, Kim L; Grimaldi, Alison; Hodges, Paul W

    2016-02-01

    Lateral hip pain during walking is a feature of gluteal tendinopathy but little is known how walking biomechanics differ in individuals with gluteal tendinopathy. This study aimed to compare walking kinematics and kinetics between individuals with and without gluteal tendinopathy. Three-dimensional walking-gait analysis was conducted on 40 individuals aged 35 to 70 years with unilateral gluteal tendinopathy and 40 pain-free controls. An analysis of covariance was used to compare kinematic and kinetic variables between groups. Linear regression was performed to investigate the relationship between kinematics and external hip adduction moment in the gluteal tendinopathy group. Individuals with gluteal tendinopathy demonstrated a greater hip adduction moment throughout stance than controls (standardized mean difference ranging from 0.60 (first peak moment) to 0.90 (second peak moment)). Contralateral trunk lean at the time of the first peak hip adduction moment was 1.2 degrees greater (P=0.04), and pelvic drop at the second peak hip adduction moment 1.4 degrees greater (P=0.04), in individuals with gluteal tendinopathy. Two opposite trunk and pelvic strategies were also identified within the gluteal tendinopathy group. Contralateral pelvic drop was significantly correlated with the first (R=0.35) and second peak (R=0.57) hip adduction moment, and hip adduction angle with the second peak hip adduction moment (R=-0.36) in those with gluteal tendinopathy. Individuals with gluteal tendinopathy exhibit greater hip adduction moments and alterations in trunk and pelvic kinematics during walking. Findings provide a basis to consider frontal plane pelvic control in the management of gluteal tendinopathy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Effects of worn-out soles on lower limb stability, shock absorption and energy cost during prolonged walking.

    Science.gov (United States)

    Saito, Seiji; Muraki, Satoshi; Tochihara, Yutaka

    2007-09-01

    This study investigated the effects of worn-out shoes on lower leg stability, shock absorption and energy cost during prolonged walking. Seven male subjects (23.4 +/- 0.5 yr) walked at 4.8 km/h for 60 minutes wearing three different pairs of shoes: two of these pairs had severely and moderately worn soles (EASC: Excessive Attrite Shoe Condition and MASC: Moderate Attrite Shoe Condition, respectively) and the other pair had no wear (NASC: No Attrite Shoe Condition). Impact acceleration at the subtalar at heel strike, rearfoot angles (the subtalar joint and the lower leg) during stance phase, and oxygen uptake (VO2) were measured throughout the 60-minute walk. At the 10th minute of walking, worn-out shoes increased the supination of the subtalar joint and extortion of the lower leg. In addition, VO2 was significant larger in EASC (808.3 ml x min(-1)) than in NASC (749.5 ml x min(-1)). During the 60-minute walk, however, there were no time effects of shoe condition on the rearfoot angles and on VO2. In contrast, impact acceleration at the subtalar joint in EASC remained almost constant until the 30th minute of walking, and then began to elevate. In conclusion, worn-out shoes increased the energy cost and reduced lower leg stability during walking, although these changes were not influenced by walking duration within 60 minutes. However, prolonged walking showed the potential negative effect of worn-out shoe on shock absorption.

  4. Biomechanics of uphill walking using custom ankle-foot orthoses of three different stiffnesses.

    Science.gov (United States)

    Haight, Derek J; Russell Esposito, Elizabeth; Wilken, Jason M

    2015-03-01

    Ankle-foot orthoses (AFOs) can provide support and improve walking ability in individuals with plantarflexor weakness. Passive-dynamic AFO stiffness can be optimized for over-ground walking, however little research exists for uphill walking, when plantarflexor contributions are key. Compare uphill walking biomechanics (1) between dynamic AFO users and able-bodied control subjects. (2) between injured and sound limbs (3) across different AFO stiffnesses. Twelve patients with unilateral limb-salvage and twelve matched, able-bodied controls underwent biomechanical gait analysis when walking up a 10° incline. Three AFO stiffnesses were tested in the patient group: Nominal (clinically prescribed), Compliant (20% less stiff), and Stiff (20% more stiff). AFO users experienced less ankle motion and power generation, lower knee extensor moments, and greater hip flexion and power generation than controls during uphill walking. Despite these deviations, they walked at equivalent self-selected velocities and stride lengths. Asymmetries were present at the ankle and knee with decreased ankle motion and power, and lower knee extensor moments on the AFO limb. Stiffer AFOs increased knee joint flexion but a 40% range in AFO stiffness had few other effects on gait. Therefore, a wide range of clinically prescribed AFO stiffnesses may adequately assist uphill walking. Published by Elsevier B.V.

  5. Skeletal adaptations for forwards and sideways walking in three species of decapod crustaceans.

    Science.gov (United States)

    Vidal-Gadea, A G; Rinehart, M D; Belanger, J H

    2008-03-01

    Crustaceans have been successfully employed to study legged locomotion for decades. Most studies have focused on either forwards-walking macrurans, or sideways-walking brachyurans. Libinia emarginata is a Majoid crab (Brachyura) and as such belongs to the earliest group to have evolved the crab form from homoloid ancestors. Unlike most brachyurans, Libinia walks forwards 80% of the time. We employed standard anatomical techniques and motion analysis to compare the skeleton, stance, and the range of motion of the legs of Libinia to the sideways-walking green shore crab (Carcinus maenas), and to the forwards-walking crayfish (Procambarus clarkii). We found animals tended to have greater ranges of motion for joints articulating in the preferred direction of locomotion. Leg segments proximal to such joints were comparatively longer. Thorax elongation, leg length and placement at rest also reflected walking preference. Comparative studies of walking in Libinia and other brachyurans may shed light on the neuroethology of legged locomotion, and on the anatomical and physiological changes necessary for sideways-walking in crustaceans.

  6. Walk-Startup of a Two-Legged Walking Mechanism

    Science.gov (United States)

    Babković, Kalman; Nagy, László; Krklješ, Damir; Borovac, Branislav

    There is a growing interest towards humanoid robots. One of their most important characteristic is the two-legged motion - walk. Starting and stopping of humanoid robots introduce substantial delays. In this paper, the goal is to explore the possibility of using a short unbalanced state of the biped robot to quickly gain speed and achieve the steady state velocity during a period shorter than half of the single support phase. The proposed method is verified by simulation. Maintainig a steady state, balanced gait is not considered in this paper.

  7. Intraspinal microstimulation produces over-ground walking in anesthetized cats

    Science.gov (United States)

    Holinski, B. J.; Mazurek, K. A.; Everaert, D. G.; Toossi, A.; Lucas-Osma, A. M.; Troyk, P.; Etienne-Cummings, R.; Stein, R. B.; Mushahwar, V. K.

    2016-10-01

    Objective. Spinal cord injury causes a drastic loss of motor, sensory and autonomic function. The goal of this project was to investigate the use of intraspinal microstimulation (ISMS) for producing long distances of walking over ground. ISMS is an electrical stimulation method developed for restoring motor function by activating spinal networks below the level of an injury. It produces movements of the legs by stimulating the ventral horn of the lumbar enlargement using fine penetrating electrodes (≤50 μm diameter). Approach. In each of five adult cats (4.2-5.5 kg), ISMS was applied through 16 electrodes implanted with tips targeting lamina IX in the ventral horn bilaterally. A desktop system implemented a physiologically-based control strategy that delivered different stimulation patterns through groups of electrodes to evoke walking movements with appropriate limb kinematics and forces corresponding to swing and stance. Each cat walked over an instrumented 2.9 m walkway and limb kinematics and forces were recorded. Main results. Both propulsive and supportive forces were required for over-ground walking. Cumulative walking distances ranging from 609 to 835 m (longest tested) were achieved in three animals. In these three cats, the mean peak supportive force was 3.5 ± 0.6 N corresponding to full-weight-support of the hind legs, while the angular range of the hip, knee, and ankle joints were 23.1 ± 2.0°, 29.1 ± 0.2°, and 60.3 ± 5.2°, respectively. To further demonstrate the viability of ISMS for future clinical use, a prototype implantable module was successfully implemented in a subset of trials and produced comparable walking performance. Significance. By activating inherent locomotor networks within the lumbosacral spinal cord, ISMS was capable of producing bilaterally coordinated and functional over-ground walking with current amplitudes <100 μA. These exciting results suggest that ISMS may be an effective intervention for restoring functional

  8. Randomized Controlled Theory-Based, E-Mail-Mediated Walking Intervention.

    Science.gov (United States)

    Richards, Elizabeth A; Ogata, Niwako; Cheng, Ching-Wei

    2017-02-01

    The purpose of this study was to evaluate the ability of two concurrent randomized controlled interventions based on social cognitive theory to increase walking. A second purpose was to compare the efficacy of the intervention between two distinct groups: dog owners and non-dog owners. Adult dog owners ( n = 40) and non-dog owners ( n = 65) were randomized into control or intervention groups. Intervention groups received bi-weekly emails for first 4 weeks and then weekly email for the next 8 weeks targeting self-efficacy, social support, goal setting, and benefits/barriers to walking. Dog owner messages focused on dog walking while non-dog owners received general walking messages. Control groups received a 1-time email reviewing current physical activity guidelines. At 6 months, both intervention groups reported greater increases in walking and maintained these increases at 12 months. The greatest increases were seen in the dog owner intervention group. In conclusion, dog owners accumulated more walking, which may be attributed to the dog-owner relationship.

  9. System overview and walking dynamics of a passive dynamic walking robot with flat feet

    Directory of Open Access Journals (Sweden)

    Xinyu Liu

    2015-12-01

    Full Text Available The concept of “passive dynamic walking robot” refers to the robot that can walk down a shallow slope stably without any actuation and control which shows a limit cycle during walking. By adding actuation at some joints, the passive dynamic walking robot can walk stably on level ground and exhibit more versatile gaits than fully passive robot, namely, the “limit cycle walker.” In this article, we present the mechanical structures and control system design for a passive dynamic walking robot with series elastic actuators at hip joint and ankle joints. We built a walking model that consisted of an upper body, knee joints, and flat feet and derived its walking dynamics that involve double stance phases in a walking cycle based on virtual power principle. The instant just before impact was chosen as the start of one step to reduce the number of independent state variables. A numerical simulation was implemented by using MATLAB, in which the proposed passive dynamic walking model could walk stably down a shallow slope, which proves that the derived walking dynamics are correct. A physical passive robot prototype was built finally, and the experiment results show that by only simple control scheme the passive dynamic robot could walk stably on level ground.

  10. Prevention of downhill walking-induced muscle damage by non-damaging downhill walking.

    Science.gov (United States)

    Maeo, Sumiaki; Yamamoto, Masayoshi; Kanehisa, Hiroaki; Nosaka, Kazunori

    2017-01-01

    Mountain trekking involves level, uphill, and downhill walking (DW). Prolonged DW induces damage to leg muscles, reducing force generating ability and muscle coordination. These increase risks for more serious injuries and accidents in mountain trekking, thus a strategy to minimize muscle damage is warranted. It has been shown that low-intensity eccentric contractions confer protective effect on muscle damage induced by high-intensity eccentric contractions. This study tested the hypothesis that 5-min non-damaging DW would attenuate muscle damage induced by 40-min DW, but 5-min level walking (LW) would not. Untrained young men were allocated (n = 12/group) to either a control or one of the two preconditioning groups (PRE-DW or PRE-LW). The PRE-DW and PRE-LW groups performed 5-min DW (-28%) and 5-min LW, respectively, at 5 km/h with a load of 10% body mass, 1 week before 40-min DW (-28%, 5 km/h, 10% load). The control group performed 40-min DW only. Maximal knee extension strength, plasma creatine kinase (CK) activity, and muscle soreness (0-100 mm visual analogue scale) were measured before and 24 h after 5-min DW and 5-min LW, and before and 24, 48, and 72 h after 40-min DW. No significant changes in any variables were evident after 5-min DW and 5-min LW. After 40-min DW, the control and PRE-LW groups showed significant (P<0.05) changes in the variables without significant differences between groups (control vs. PRE-LW; peak strength reduction: -19.2 ± 6.9% vs. -18.7 ± 11.0%, peak CK: 635.5 ± 306.0 vs. 639.6 ± 405.4 U/L, peak soreness: 81.4 ± 14.8 vs. 72.0 ± 29.2 mm). These changes were significantly (P<0.05) attenuated (47-64%) for the PRE-DW group (-9.9 ± 9.6%, 339.3 ± 148.4 U/L, 27.8 ± 16.8 mm). The results supported the hypothesis and suggest that performing small volume of downhill walking is crucial in preparation for trekking.

  11. Enhanced spinal excitation from ankle flexors to knee extensors during walking in stroke patients

    DEFF Research Database (Denmark)

    Achache, V.; Mazevet, D.; Iglesias, C.

    2010-01-01

    OBJECTIVES: It is still unclear to what an extent altered reflex activity contributes to gait deficit following stroke. Spinal group I and group II excitations from ankle dorsiflexors to knee extensors were investigated during post-stroke walking. METHODS: Electrical stimulation was applied...... to the common peroneal nerve (CPN) in the early stance, and the short-latency biphasic excitation in Quadriceps motoneurones was evaluated from the Vastus Lateralis (VL) rectified and averaged (N=50) EMG activity in 14 stroke patients walking at 0.6-1.6 km/h, and 14 control subjects walking at 3.2-4.8 and at 1......: The spinal, presumed group II, excitation from ankle dorsiflexors to knee extensors is particularly enhanced during post-stroke walking probably due to plastic adaptations in the descending control. SIGNIFICANCE: This adaptation may help to stabilize the knee in early stance when the patients have recover...

  12. Full revivals in 2D quantum walks

    Energy Technology Data Exchange (ETDEWEB)

    Stefanak, M; Jex, I [Department of Physics, FJFI CVUT v Praze, Brehova 7, 115 19 Praha 1-Stare Mesto (Czech Republic); Kollar, B; Kiss, T, E-mail: martin.stefanak@fjfi.cvut.c [Department of Quantum Optics and Quantum Information, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Konkoly-Thege M. u. 29-33, H-1121 Budapest (Hungary)

    2010-09-01

    Recurrence of a random walk is described by the Polya number. For quantum walks, recurrence is understood as the return of the walker to the origin, rather than the full revival of its quantum state. Localization for two-dimensional quantum walks is known to exist in the sense of non-vanishing probability distribution in the asymptotic limit. We show, on the example of the 2D Grover walk, that one can exploit the effect of localization to construct stationary solutions. Moreover, we find full revivals of a quantum state with a period of two steps. We prove that there cannot be longer cycles for a four-state quantum walk. Stationary states and revivals result from interference, which has no counterpart in classical random walks.

  13. Quantum walks public key cryptographic system

    OpenAIRE

    Vlachou, C; Rodrigues, J.; Mateus, P.; Paunković, N.; Souto, A.

    2016-01-01

    Quantum Cryptography is a rapidly developing field of research that benefits from the properties of Quantum Mechanics in performing cryptographic tasks. Quantum walks are a powerful model for quantum computation and very promising for quantum information processing. In this paper, we present a quantum public-key cryptographic system based on quantum walks. In particular, in the proposed protocol the public key is given by a quantum state generated by performing a quantum walk. We show that th...

  14. Quantum random walks - an introductory overview

    CERN Document Server

    Kempe, J

    2003-01-01

    This article aims to provide an introductory survey on quantum random walks. Starting from a physical effect to illustrate the main ideas we will introduce quantum random walks, review some of their properties and outline their striking differences to classical walks. We will touch upon both physical effects and computer science applications, introducing some of the main concepts and language of present day quantum information science in this context. We will mention recent developments in this new area and outline some open questions.

  15. Random Walk Smooth Transition Autoregressive Models

    OpenAIRE

    2004-01-01

    This paper extends the family of smooth transition autoregressive (STAR) models by proposing a specification in which the autoregressive parameters follow random walks. The random walks in the parameters can capture structural change within a regime switching framework, but in contrast to the time varying STAR (TV-STAR) speciifcation recently introduced by Lundbergh et al (2003), structural change in our random walk STAR (RW-STAR) setting follows a stochastic process rather than a determinist...

  16. Gaitography applied to prosthetic walking.

    Science.gov (United States)

    Roerdink, Melvyn; Cutti, Andrea G; Summa, Aurora; Monari, Davide; Veronesi, Davide; van Ooijen, Mariëlle W; Beek, Peter J

    2014-11-01

    During walking on an instrumented treadmill with an embedded force platform or grid of pressure sensors, center-of-pressure (COP) trajectories exhibit a characteristic butterfly-like shape, reflecting the medio-lateral and anterior-posterior weight shifts associated with alternating steps. We define "gaitography" as the analysis of such COP trajectories during walking (the "gaitograms"). It is currently unknown, however, if gaitography can be employed to characterize pathological gait, such as lateralized gait impairments. We therefore registered gaitograms for a heterogeneous sample of persons with a trans-femoral and trans-tibial amputation during treadmill walking at a self-selected comfortable speed. We found that gaitograms directly visualize between-person differences in prosthetic gait in terms of step width and the relative duration of prosthetic and non-prosthetic single-support stance phases. We further demonstrated that one should not only focus on the gaitogram's shape but also on the time evolution along that shape, given that the COP evolves much slower in the single-support phase than in the double-support phase. Finally, commonly used temporal and spatial prosthetic gait characteristics were derived, revealing both individual and systematic differences in prosthetic and non-prosthetic step lengths, step times, swing times, and double-support durations. Because gaitograms can be rapidly collected in an unobtrusive and markerless manner over multiple gait cycles without constraining foot placement, clinical application of gaitography seems both expedient and appealing. Studies examining the repeatability of gaitograms and evaluating gaitography-based gait characteristics against a gold standard with known validity and reliability are required before gaitography can be clinically applied.

  17. Kinematic and ground reaction force accommodation during weighted walking.

    Science.gov (United States)

    James, C Roger; Atkins, Lee T; Yang, Hyung Suk; Dufek, Janet S; Bates, Barry T

    2015-12-01

    Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability.

  18. Random Walks Estimate Land Value

    CERN Document Server

    Blanchard, Ph

    2010-01-01

    Expected urban population doubling calls for a compelling theory of the city. Random walks and diffusions defined on spatial city graphs spot hidden areas of geographical isolation in the urban landscape going downhill. First--passage time to a place correlates with assessed value of land in that. The method accounting the average number of random turns at junctions on the way to reach any particular place in the city from various starting points could be used to identify isolated neighborhoods in big cities with a complex web of roads, walkways and public transport systems.

  19. Quantum Walks for Computer Scientists

    CERN Document Server

    Venegas-Andraca, Salvador

    2008-01-01

    Quantum computation, one of the latest joint ventures between physics and the theory of computation, is a scientific field whose main goals include the development of hardware and algorithms based on the quantum mechanical properties of those physical systems used to implement such algorithms. Solving difficult tasks (for example, the Satisfiability Problem and other NP-complete problems) requires the development of sophisticated algorithms, many of which employ stochastic processes as their mathematical basis. Discrete random walks are a popular choice among those stochastic processes. Inspir

  20. Motor modules in robot-aided walking

    Directory of Open Access Journals (Sweden)

    Gizzi Leonardo

    2012-10-01

    Full Text Available Abstract Background It is hypothesized that locomotion is achieved by means of rhythm generating networks (central pattern generators and muscle activation generating networks. This modular organization can be partly identified from the analysis of the muscular activity by means of factorization algorithms. The activity of rhythm generating networks is described by activation signals whilst the muscle intervention generating network is represented by motor modules (muscle synergies. In this study, we extend the analysis of modular organization of walking to the case of robot-aided locomotion, at varying speed and body weight support level. Methods Non Negative Matrix Factorization was applied on surface electromyographic signals of 8 lower limb muscles of healthy subjects walking in gait robotic trainer at different walking velocities (1 to 3km/h and levels of body weight support (0 to 30%. Results The muscular activity of volunteers could be described by low dimensionality (4 modules, as for overground walking. Moreover, the activation signals during robot-aided walking were bursts of activation timed at specific phases of the gait cycle, underlying an impulsive controller, as also observed in overground walking. This modular organization was consistent across the investigated speeds, body weight support level, and subjects. Conclusions These results indicate that walking in a Lokomat robotic trainer is achieved by similar motor modules and activation signals as overground walking and thus supports the use of robotic training for re-establishing natural walking patterns.

  1. Excited random walks: results, methods, open problems

    CERN Document Server

    Kosygina, Elena

    2012-01-01

    We consider a class of self-interacting random walks in deterministic or random environments, known as excited random walks or cookie walks, on the d-dimensional integer lattice. The main purpose of this paper is two-fold: to give a survey of known results and some of the methods and to present several new results. The latter include functional limit theorems for transient one-dimensional excited random walks in bounded i.i.d. cookie environments as well as some zero-one laws. Several open problems are stated.

  2. Quantum walk with one variable absorbing boundary

    Science.gov (United States)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks.

  3. Walking in Place Through Virtual Worlds

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    Immersive virtual reality (IVR) is seemingly on the verge of entering the homes of consumers. Enabling users to walk through virtual worlds in a limited physical space presents a challenge. With an outset in a taxonomy of virtual travel techniques, we argue that Walking-in-Place (WIP) techniques...... constitute a promising approach to virtual walking in relation to consumer IVR. Subsequently we review existing approaches to WIP locomotion and highlight the need for a more explicit focus on the perceived naturalness of WIP techniques; i.e., the degree to which WIP locomotion feels like real walking...

  4. Random walks on coset spaces with applications to Furstenberg entropy

    CERN Document Server

    Bowen, Lewis

    2010-01-01

    We study the Poisson boundary of a random walk on the coset space of a random subgroup of a locally compact group whose law is conjugation-invariant. Then we construct a path of ergodic stationary actions of the free group on which the Furstenberg entropy varies continuously, thereby solving the Furstenberg entropy realization problem for free groups. This result is motivated by the general problem of understanding the structure of stationary actions and more specifically by works of Nevo and Zimmer which proved the Furstenberg entropies of stationary actions of a higher rank semisimple Lie group satisfying a certain mixing condition are restricted to a finite set.

  5. Characteristics associated with US Walk to School programs

    Directory of Open Access Journals (Sweden)

    Neelon Brian

    2007-12-01

    Full Text Available Abstract Participation in Walk to School (WTS programs has grown substantially in the US since its inception; however, no attempt has been made to systematically describe program use or factors associated with implementation of environment/policy changes. Objective Describe the characteristics of schools' WTS programs by level of implementation. Methods Representatives from 450 schools from 42 states completed a survey about their WTS program's infrastructure and activities, and perceived impact on walking to school. Level of implementation was determined from a single question to which respondents reported participation in WTS Day only (low, WTS Day and additional programs (medium, or making policy/environmental change (high. Results The final model showed number of community groups involved was positively associated with higher level of implementation (OR = 1.78, 95%CI = 1.44, 2.18, as was funding (OR = 1.56, 95%CI = 1.26, 1.92, years of participation (OR = 1.44, 95% CI = 1.23, 1.70, and use of a walkability assessment (OR = 3.22, 95%CI = 1.84, 5.64. Implementation level was modestly associated with increased walking (r = 0.18. Conclusion Strong community involvement, some funding, repeat participation, and environmental audits are associated with progms that adopt environmental/policy change, and seem to facilitate walking to school.

  6. [Familiarization to treadmill walking in unimpaired Parkinson's disease patients].

    Science.gov (United States)

    Pérez-Sanpablo, Alberto Isaac; Hernández-Arenas, Claudia; Rodríguez-Reyes, Gerardo; Quiñones-Uriostegui, Ivett; Alessi Montero, Aldo; Núñez-Carrera, Lidia; Boll-Woehrlen, Marie Catherine; Galván Duque-Gastélum, Carlos

    2014-07-01

    Familiarization to treadmill walking in unimpaired Parkinson's disease (PD) patients is assessed, across multiple treadmill walking sessions. Thirteen PD subjects were enrolled into the study (Eight were in a moderate stage of the disease, and 5 in an advanced stage). PD subjects attended a progressive program consisting of 12 sessions of 20 min. Walking speed, cadence, step length and coefficient of variation were assessed. ANOVA test were used to evaluate progression of disease and time influence over familiarization. PD Subjects baseline characteristics did not differ significantly between both groups and typical dependencies over progression of disease and velocity were found for cadence, step length and coefficient of variation. However, we showed that some PD subjects may require longer familiarization times and that familiarization is an adaptation process which involves parameters as velocity, cadence and gait stability. A better definition of familiarization to treadmill is needed since some parameters such as step length does not change significantly while others such as cadence, coefficient of variation and intraclass correlation coefficient does. Therefore familiarization to treadmill walking should remain on measures of velocity, cadence, reliability and variability. However, a bigger sample size is needed in order to improve the results of the present study.

  7. Walk the line: station context, corridor type and bus rapid transit walk access in Jinan, China

    OpenAIRE

    Jiang, Yang; Mehndiratta, Shomik; Zegras, P. Christopher

    2011-01-01

    This paper examines BRT station walk access patterns in rapidly urbanizing China and the relationship between bus rapid transit (BRT) station context and corridor type and the distance people will walk to access the system (i.e., catchment area). We hypothesize that certain contextual built environment features and station and right-of-way configurations will increase the walk-access catchment area; that is, that urban design influences users’ willingness to walk to BRT. We base our analysis ...

  8. Walking execution is not affected by divided attention in patients with multiple sclerosis with no disability, but there is a motor planning impairment

    Directory of Open Access Journals (Sweden)

    Leandro Alberto Calazans Nogueira

    2013-08-01

    Full Text Available Purpose: We analysed the cognitive influence on walking in multiple sclerosis (MS patients, in the absence of clinical disability. Method: A case-control study was conducted with 12 MS patients with no disability and 12 matched healthy controls. Subjects were referred for completion a timed walk test of 10 m and a 3D-kinematic analysis. Participants were instructed to walk at a comfortable speed in a dual-task (arithmetic task condition, and motor planning was measured by mental chronometry. Results: Scores of walking speed and cadence showed no statistically significant differences between the groups in the three conditions. The dual-task condition showed an increase in the double support duration in both groups. Motor imagery analysis showed statistically significant differences between real and imagined walking in patients. Conclusion: MS patients with no disability did not show any influence of divided attention on walking execution. However, motor planning was overestimated as compared with real walking.

  9. Overground vs. treadmill walking on biomechanical energy harvesting: An energetics and EMG study.

    Science.gov (United States)

    Martin, Jean-Paul; Li, Qingguo

    2017-02-01

    A biomechanical energy harvester is a wearable device that generates electricity from human motion. Walking on a treadmill has been used almost exclusively by researchers for studying the energetic effects of biomechanical energy harvesters and wearable robotics. A treadmill provides the advantage of having long duration trials within a stationary motion capture volume. However, no consensus exists on whether the results from treadmill walking accurately represent overground walking. We aim to investigate how a biomechanical energy harvester performs overground compared to on a treadmill by measuring energy expenditure and muscle activity. Participants (n=15) walked both overground and on a treadmill with and without a lower limb-driven biomechanical energy harvester. Energy expenditure was measured using indirect calorimetry and muscle activity was collected with surface electromyograms on seven superficial lower limb muscles. We observed a similar increase in metabolic cost of transport (Δoverground: 0.28±0.24J/kgm, Δtreadmill: 0.30±0.24J/kgm) from normal walking (overground: 2.56±0.33J/kgm, treadmill: 3.39±0.31J/kgm) to harvester walking (overground: 2.83±0.35J/kgm, treadmill: 3.69±0.32J/kgm) in both walking modes (p>0.05). This was accompanied a significant increase in muscle activity of select muscle groups (penergy harvester, treadmill will give similar net increases when compared to a controlled walking condition, such as normal walking, on the same walking surface.

  10. IMU-based ambulatory walking speed estimation in constrained treadmill and overground walking.

    Science.gov (United States)

    Yang, Shuozhi; Li, Qingguo

    2012-01-01

    This study evaluated the performance of a walking speed estimation system based on using an inertial measurement unit (IMU), a combination of accelerometers and gyroscopes. The walking speed estimation algorithm segments the walking sequence into individual stride cycles (two steps) based on the inverted pendulum-like behaviour of the stance leg during walking and it integrates the angular velocity and linear accelerations of the shank to determine the displacement of each stride. The evaluation was performed in both treadmill and overground walking experiments with various constraints on walking speed, step length and step frequency to provide a relatively comprehensive assessment of the system. Promising results were obtained in providing accurate and consistent walking speed/step length estimation in different walking conditions. An overall percentage root mean squared error (%RMSE) of 4.2 and 4.0% was achieved in treadmill and overground walking experiments, respectively. With an increasing interest in understanding human walking biomechanics, the IMU-based ambulatory system could provide a useful walking speed/step length measurement/control tool for constrained walking studies.

  11. Study of human walking patterns based on the parameter optimization of a passive dynamic walking robot.

    Science.gov (United States)

    Zang, Xizhe; Liu, Xinyu; Zhu, Yanhe; Zhao, Jie

    2016-04-29

    The study of human walking patterns mainly focuses on how control affects walking because control schemes are considered to be dominant in human walking. This study proposes that not only fine control schemes but also optimized body segment parameters are responsible for humans' low-energy walking. A passive dynamic walker provides the possibility of analyzing the effect of parameters on walking efficiency because of its ability to walk without any control. Thus, a passive dynamic walking model with a relatively human-like structure was built, and a parameter optimization process based on the gait sensitivity norm was implemented to determine the optimal mechanical parameters by numerical simulation. The results were close to human body parameters, thus indicating that humans can walk under a passive pattern based on their body segment parameters. A quasi-passive walking prototype was built on the basis of the optimization results. Experiments showed that a passive robot with optimized parameters could walk on level ground with only a simple hip actuation. This result implies that humans can walk under a passive pattern based on their body segment parameters with only simple control strategy implying that humans can opt to walk instinctively under a passive pattern.

  12. Interlimb coordination during forward walking is largely preserved in backward walking in children with cerebral palsy

    NARCIS (Netherlands)

    Meyns, P.; Molenaers, G.; Desloovere, K.; Duysens, J.E.J.

    2014-01-01

    OBJECTIVE: Limb kinematics in backward walking (BW) are essentially those of forward walking (FW) in reverse. It has been argued that subcortical mechanisms could underlie both walking modes. METHODS: Therefore, we tested whether participants with supraspinal/cortical deficits (i.e. cerebral palsy)

  13. Spatial search by quantum walk

    CERN Document Server

    Childs, A M; Childs, Andrew M.; Goldstone, Jeffrey

    2003-01-01

    Grover's quantum search algorithm provides a way to speed up combinatorial search, but is not directly applicable to searching a physical database. Nevertheless, Aaronson and Ambainis showed that a database of N items laid out in d spatial dimensions can be searched in time of order sqrt(N) for d>2, and in time of order sqrt(N) poly(log N) for d=2. We consider an alternative search algorithm based on a continuous time quantum walk on a graph. The case of the complete graph gives the continuous time search algorithm of Farhi and Gutmann, and other previously known results can be used to show that sqrt(N) speedup can also be achieved on the hypercube. We show that full sqrt(N) speedup can be achieved on a d-dimensional periodic lattice for d>4. In d=4, the quantum walk search algorithm takes time of order sqrt(N) poly(log N), and in d<4, the algorithm provides no speedup.

  14. Association between neighborhood walkability and GPS-measured walking, bicycling and vehicle time in adolescents

    DEFF Research Database (Denmark)

    Carlson, Jordan A.; Saelens, Brian E.; Kerr, Jacqueline

    2015-01-01

    Objectives: To investigate relations of walking, bicycling and vehicle time to neighborhood walkability and total physical activity in youth. Methods: Participants (N=690) were from 380 census block groups of high/low walkability and income in two US regions. Home neighborhood residential density......, intersection density, retail density, entertainment density and walkability were derived using GIS. Minutes/day of walking, bicycling and vehicle time were derived from processing algorithms applied to GPS. Accelerometers estimated total daily moderate-to-vigorous physical activity (MVPA). Models were adjusted...... for nesting of days (N=2987) within participants within block groups. Results: Walking occurred on 33%, active travel on 43%, and vehicle time on 91% of the days observed. Intersection density and neighborhood walkability were positively related to walking and bicycling and negatively related to vehicle time...

  15. Association between neighborhood walkability and GPS-measured walking, bicycling and vehicle time in adolescents

    DEFF Research Database (Denmark)

    Carlson, Jordan A.; Saelens, Brian E.; Kerr, Jacqueline;

    2015-01-01

    Objectives: To investigate relations of walking, bicycling and vehicle time to neighborhood walkability and total physical activity in youth. Methods: Participants (N=690) were from 380 census block groups of high/low walkability and income in two US regions. Home neighborhood residential density......, intersection density, retail density, entertainment density and walkability were derived using GIS. Minutes/day of walking, bicycling and vehicle time were derived from processing algorithms applied to GPS. Accelerometers estimated total daily moderate-to-vigorous physical activity (MVPA). Models were adjusted...... for nesting of days (N=2987) within participants within block groups. Results: Walking occurred on 33%, active travel on 43%, and vehicle time on 91% of the days observed. Intersection density and neighborhood walkability were positively related to walking and bicycling and negatively related to vehicle time...

  16. Treadmill walking is not equivalent to overground walking for the study of walking smoothness and rhythmicity in older adults.

    Science.gov (United States)

    Row Lazzarini, Brandi S; Kataras, Theodore J

    2016-05-01

    Treadmills are appealing for gait studies, but some gait mechanics are disrupted during treadmill walking. The purpose of this study was to examine the effects of speed and treadmill walking on walking smoothness and rhythmicity of 40 men and women between the ages of 70-96 years. Gait smoothness was examined during overground (OG) and treadmill (TM) walking by calculating the harmonic ratio from linear accelerations measured at the level of the lumbar spine. Rhythmicity was quantified as the stride time standard deviation. TM walking was performed at two speeds: a speed matching the natural OG walk speed (TM-OG), and a preferred TM speed (PTM). A dual-task OG condition (OG-DT) was evaluated to determine if TM walking posed a similar cognitive challenge. Statistical analysis included a one-way Analysis of Variance with Bonferroni corrected post hoc comparisons and the Wilcoxon signed rank test for non-normally distributed variables. Average PTM speed was slower than OG. Compared to OG, those who could reach the TM-OG speed (74.3% of sample) exhibited improved ML smoothness and rhythmicity, and the slower PTM caused worsened vertical and AP smoothness, but did not affect rhythmicity. PTM disrupted smoothness and rhythmicity differently than the OG-DT condition, likely due to reduced speed. The use of treadmills for gait smoothness and rhythmicity studies in older adults is problematic; some participants will not achieve OG speed during TM walking, walking at the TM-OG speed artificially improves rhythmicity and ML smoothness, and walking at the slower PTM speed worsens vertical and AP gait smoothness.

  17. [Recovery of walk in persons with stroke and heart disease].

    Science.gov (United States)

    Kapidzić-Duraković, Suada; Karabegović, Azra; Zonić-Imamović, Majda

    2006-01-01

    The goal of this research is to analyze the differences in recovery of walk of two groups of patients who have suffered the stroke--those who have and have not suffered from heart disease prior to the stroke. Test group consisted of patients who have suffered the stroke, and have been rehabilitated in the Clinic for physical medicine and rehabilitation in Tuzla, in 2003. Patients who have had a heart disease before suffering the stroke and have been treated by a cardiologist comprised the first test group (Group I, N=48), while patients without previous heart disease comprised the second test group (Group II, N=69). In relation to their ability to walk, patients have been divided into three groups: those who are able to walk without help, those who are not able to walk and those who are able to walk with a walking aid. Therapies used include kinesiotherapy, paraffin, criotherapy, and electro procedures. Total number of those rehabilitated in the hospital after the stroke is 117, out of which 45 (38.5 %) were women and 72 (61.5 %) men, with average of 68 +/- 9,2 years of age. According to the kind of stroke suffered, 105 patients have had ischemia (89.7 %) and 12 have had hemorrhagia (10.3 %). The highest number of patients have had paralysis of the left side of the body--48 (41.0 %), then paralysis of the right side--43 (36.8 %) and both sides--15 (12.8 %). In relation to the localization of the changes in the brain detected in the CT, the highest number of patients have had multiply lacunar changes--41 (35,0 %), then changes in parietal area--33 (28.2 %) and temporoparietal area--22 (18.8 %), and a bit less had changes in capsula interna--15 (12.8 %), occipital--3 (2.6 %) and cerebellum--3 (2.6 %). In relation to the heart diseases, most of the patients have had compensated weakness of the heart--20 (41.7 %), suffered infarctus myocardii--8 (16.7 %) and atrial fibrillation--8 (16.7 %), with angina pectoris 6 (12,5 %), with arrhitmia--3 (6.3 %) and heart surgery--3

  18. A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index

    Science.gov (United States)

    Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

    2009-12-01

    The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

  19. Downhill walking to improve lower limb strength in healthy young adults.

    Science.gov (United States)

    Rodio, Angelo; Fattorini, Luigi

    2014-01-01

    Walking is the most natural physical activity to maintain and improve fitness and health. Walking downhill is usefully adopted to plan training programmes to improve the strength, particularly in older adults. The present research was aimed to evaluate the influence of downhill walking on leg strength in young adult. A total of 32 females (age 26 ± 4 years; height 1.64 ± 0.05 m; body mass 57.6 ± 5.6 kg) were divided into four groups and they carried out an exercise intervention consisting of three sessions per week for 6 weeks, each lasting 30 minutes. Groups were defined at several workloads characterised by treadmill inclination (%) and walking speed (m · s(-1)): Level Walking at treadmill inclination 0% and walking speed 1.0; Uphill Walking at +20%, 0.75; Downhill Walking (DW) at -20%, 1.36; and Mixed Walking at +20%, 0.75 and -20%, 1.36 each lasting 15 minutes. Maximum voluntary contraction (MVC) developed by the Quadriceps Femoris and Endurance Time at 60% MVC were evaluated before and after experimental period. At the end of each session, Borg's scale and Visual Analogue Scale (VAS) were adopted in order to evaluate perception of rate exertion and pain. Statistical analysis showed significant only in MVC for DW in both right and left legs. Borg's scale and VAS described light activity free of pain. Present findings showed how an eccentric exercise, short lasting and at a low workload, can be useful in inducing improvements in leg strength.

  20. Walking on high heels changes muscle activity and the dynamics of human walking significantly

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Svendsen, Morten Bo Søndergaard; Nørreslet, Andreas;

    2012-01-01

    The aim of the study was to investigate the distribution of net joint moments in the lower extremities during walking on high-heeled shoes compared with barefooted walking at identical speed. Fourteen female subjects walked at 4 km/h across three force platforms while they were filmed by five...... digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...

  1. Walking (Gait), Balance, and Coordination Problems

    Science.gov (United States)

    ... Seeking Services: Questions to Ask d Employment Disclosure Decisions Career Options Accommodations d Resources for Specific Populations Pediatric ... MS Navigator Program Patient Resources Contact Us d Careers in MS ... MS Symptoms Walking (Gait) Difficulties Share this page Facebook Twitter Email Walking (Gait) ...

  2. Quantum random walks and decision making.

    Science.gov (United States)

    Shankar, Karthik H

    2014-01-01

    How realistic is it to adopt a quantum random walk model to account for decisions involving two choices? Here, we discuss the neural plausibility and the effect of initial state and boundary thresholds on such a model and contrast it with various features of the classical random walk model of decision making.

  3. Nordic walking improves mobility in Parkinson's disease.

    NARCIS (Netherlands)

    Eijkeren, FJ van; Reijmers, R.S.; Kleinveld, M.J.; Minten, A.; Bruggen, J.P.; Bloem, B.R.

    2008-01-01

    Nordic walking may improve mobility in Parkinson's disease (PD). Here, we examined whether the beneficial effects persist after the training period. We included 19 PD patients [14 men; mean age 67.0 years (range 58-76); Hoehn and Yahr stage range 1-3] who received a 6-week Nordic walking exercise pr

  4. Nordic walking improves mobility in Parkinson's disease.

    NARCIS (Netherlands)

    Eijkeren, FJ van; Reijmers, R.S.; Kleinveld, M.J.; Minten, A.; Bruggen, J.P.; Bloem, B.R.

    2008-01-01

    Nordic walking may improve mobility in Parkinson's disease (PD). Here, we examined whether the beneficial effects persist after the training period. We included 19 PD patients [14 men; mean age 67.0 years (range 58-76); Hoehn and Yahr stage range 1-3] who received a 6-week Nordic walking exercise

  5. Locomotor sequence learning in visually guided walking.

    Science.gov (United States)

    Choi, Julia T; Jensen, Peter; Nielsen, Jens Bo

    2016-04-01

    Voluntary limb modifications must be integrated with basic walking patterns during visually guided walking. In this study we tested whether voluntary gait modifications can become more automatic with practice. We challenged walking control by presenting visual stepping targets that instructed subjects to modify step length from one trial to the next. Our sequence learning paradigm is derived from the serial reaction-time (SRT) task that has been used in upper limb studies. Both random and ordered sequences of step lengths were used to measure sequence-specific and sequence-nonspecific learning during walking. In addition, we determined how age (i.e., healthy young adults vs. children) and biomechanical factors (i.e., walking speed) affected the rate and magnitude of locomotor sequence learning. The results showed that healthy young adults (age 24 ± 5 yr,n= 20) could learn a specific sequence of step lengths over 300 training steps. Younger children (age 6-10 yr,n= 8) had lower baseline performance, but their magnitude and rate of sequence learning were the same compared with those of older children (11-16 yr,n= 10) and healthy adults. In addition, learning capacity may be more limited at faster walking speeds. To our knowledge, this is the first study to demonstrate that spatial sequence learning can be integrated with a highly automatic task such as walking. These findings suggest that adults and children use implicit knowledge about the sequence to plan and execute leg movement during visually guided walking.

  6. The QWalk simulator of quantum walks

    Science.gov (United States)

    Marquezino, F. L.; Portugal, R.

    2008-09-01

    Several research groups are giving special attention to quantum walks recently, because this research area have been used with success in the development of new efficient quantum algorithms. A general simulator of quantum walks is very important for the development of this area, since it allows the researchers to focus on the mathematical and physical aspects of the research instead of deviating the efforts to the implementation of specific numerical simulations. In this paper we present QWalk, a quantum walk simulator for one- and two-dimensional lattices. Finite two-dimensional lattices with generic topologies can be used. Decoherence can be simulated by performing measurements or by breaking links of the lattice. We use examples to explain the usage of the software and to show some recent results of the literature that are easily reproduced by the simulator. Program summaryProgram title: QWalk Catalogue identifier: AEAX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAX_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 10 010 No. of bytes in distributed program, including test data, etc.: 172 064 Distribution format: tar.gz Programming language: C Computer: Any computer with a C compiler that accepts ISO C99 complex arithmetic (recent versions of GCC, for instance). Pre-compiled Windows versions are also provided Operating system: The software should run in any operating system with a recent C compiler. Successful tests were performed in Linux and Windows RAM: Less than 10 MB were required for a two-dimensional lattice of size 201×201. About 400 MB, for a two-dimensional lattice of size 1601×1601 Classification: 16.5 Nature of problem: Classical simulation of discrete quantum walks in one- and two-dimensional lattices. Solution method: Iterative approach without explicit representation of

  7. Do walking strategies to increase physical activity reduce reported sitting in workplaces: a randomized control trial

    Directory of Open Access Journals (Sweden)

    Burton Nicola W

    2009-07-01

    Full Text Available Abstract Background Interventions designed to increase workplace physical activity may not automatically reduce high volumes of sitting, a behaviour independently linked to chronic diseases such as obesity and type II diabetes. This study compared the impact two different walking strategies had on step counts and reported sitting times. Methods Participants were white-collar university employees (n = 179; age 41.3 ± 10.1 years; 141 women, who volunteered and undertook a standardised ten-week intervention at three sites. Pre-intervention step counts (Yamax SW-200 and self-reported sitting times were measured over five consecutive workdays. Using pre-intervention step counts, employees at each site were randomly allocated to a control group (n = 60; maintain normal behaviour, a route-based walking group (n = 60; at least 10 minutes sustained walking each workday or an incidental walking group (n = 59; walking in workday tasks. Workday step counts and reported sitting times were re-assessed at the beginning, mid- and endpoint of intervention and group mean± SD steps/day and reported sitting times for pre-intervention and intervention measurement points compared using a mixed factorial ANOVA; paired sample-t-tests were used for follow-up, simple effect analyses. Results A significant interactive effect (F = 3.5; p t = 3.9, p t = 2.5, p Conclusion Compared to controls, both route and incidental walking increased physical activity in white-collar employees. Our data suggests that workplace walking, particularly through incidental movement, also has the potential to decrease employee sitting times, but there is a need for on-going research using concurrent and objective measures of sitting, standing and walking.

  8. Design Issues for Hexapod Walking Robots

    Directory of Open Access Journals (Sweden)

    Franco Tedeschi

    2014-06-01

    Full Text Available Hexapod walking robots have attracted considerable attention for several decades. Many studies have been carried out in research centers, universities and industries. However, only in the recent past have efficient walking machines been conceived, designed and built with performances that can be suitable for practical applications. This paper gives an overview of the state of the art on hexapod walking robots by referring both to the early design solutions and the most recent achievements. Careful attention is given to the main design issues and constraints that influence the technical feasibility and operation performance. A design procedure is outlined in order to systematically design a hexapod walking robot. In particular, the proposed design procedure takes into account the main features, such as mechanical structure and leg configuration, actuating and driving systems, payload, motion conditions, and walking gait. A case study is described in order to show the effectiveness and feasibility of the proposed design procedure.

  9. Efficient quantum walk on a quantum processor

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.

    2016-05-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  10. Efficient quantum walk on a quantum processor.

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L; Wang, Jingbo B; Matthews, Jonathan C F

    2016-05-05

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  11. Getting mobile with a walking-help

    DEFF Research Database (Denmark)

    Krummheuer, Antonia Lina; Raudaskoski, Pirkko Liisa

    Ethnomethodology has been one of the few fields were mundane experiences and social ordering such as walking have been a focus of interest (e.g. Ryave and Schenkein 1974). In the present paper we want to discuss how this mundane practice sometimes needs to be achieved through the help of technology...... people with acquired brain injury were introduced to a new walking help that should enable them to walk (better). Our multimodal interaction analysis (Goodwin 2000) of the data will show how the practice of walking with this specific technology is dependent on the interplay of the material affordances...... of the technology (e.g. Gaver 1996), the bodily affordances (e.g. Sheller 2011) of the user and, furthermore, the scaffolding by an accompanying helper. The paper will discuss how movement as an enabled experience can be analysed as an entanglement of these three aspects. To do that, the situations of walk...

  12. Walk modularity and community structure in networks

    CERN Document Server

    Mehrle, David; Harkin, Anthony

    2014-01-01

    Modularity maximization has been one of the most widely used approaches in the last decade for discovering community structure in networks of practical interest in biology, computing, social science, statistical mechanics, and more. Modularity is a quality function that measures the difference between the number of edges found within clusters minus the number of edges one would statistically expect to find based on random chance. We present a natural generalization of modularity based on the difference between the actual and expected number of walks within clusters, which we call walk-modularity. Walk-modularity can be expressed in matrix form, and community detection can be performed by finding leading eigenvectors of the walk-modularity matrix. We demonstrate community detection on both synthetic and real-world networks and find that walk-modularity maximization returns significantly improved results compared to traditional modularity maximization.

  13. Active and passive contributions to joint kinetics during walking in older adults.

    Science.gov (United States)

    Silder, Amy; Heiderscheit, Bryan; Thelen, Darryl G

    2008-01-01

    The objectives of this study were to characterize the active and passive contributions to joint kinetics during walking in healthy young and older adults, and assess whether isokinetic ankle strength is associated with ankle power output during walking. Twenty healthy young (18-35 years) and 20 healthy older (65-85 years) adults participated in this study. We measured subject-specific passive-elastic joint moment-angle relationships in the lower extremity and tested maximum isokinetic ankle strength at 30 deg/s. Passive moment-angle relationships were used to estimate active and passive joint moment, power, and work quantities during walking at 80%, 100% and 120% of preferred walking speed. There were no significant differences in walking speed, step length, or cadence between the older and young adults. However, the older adults produced significantly more net positive work at the hip but less net positive work at the ankle at all walking speeds. Passive contributions to hip and ankle work did not significantly differ between groups, inferring that the older adults generated the additional hip work actively. Maximum isokinetic ankle strength was significantly less in the older adults, and correlated with peak positive plantar-flexor power at both the preferred and fast walking speeds. The results of this study suggest that age-related shifts in joint kinetics do not arise as a result of increased passive hip joint stiffness, but seem to be reflected in plantar-flexor weakness.

  14. Acute effects of walking on inflammatory and cardiovascular risk in sedentary post-menopausal women.

    Science.gov (United States)

    Davis, Jillian; Murphy, Marie; Trinick, Tom; Duly, Ellie; Nevill, Alan; Davison, Gareth

    2008-02-01

    Biochemical markers of inflammation are emerging as new predictors of risk of cardiovascular disease (CVD) and may alter acutely with exercise. Few studies have been conducted on the effects of walking on these markers or whether different walking intensities elicit varied effects. As there is growing interest in modifiable lifestyle factors such as walking to reduce CVD risk, these inflammatory responses warrant investigation. The aim of this study was to compare the effects of walking at 50% versus 70% of predicted maximal heart rate on C-reactive protein (CRP), plasma fibrinogen, and triglycerides in sedentary post-menopausal women. Twelve post-menopausal women (mean age 58 years, s +/-6; stature 1.62 m, s+/-0.06; body mass 66.8 kg, s +/-6.2) completed two 30-min treadmill walks in a randomized cross-over design. Fasted blood samples were taken (for the determination of plasma fibrinogen, CRP, and lipids) before, immediately after, and 1 and 24 h after exercise. Triglyceride concentrations decreased from pre-exercise to 24 h post exercise at both walking intensities (time x group interaction, P 0.05). The results of this study suggest that fasting plasma triglycerides are decreased on the morning after 30 min of brisk walking at either 50% or 70% of maximal heart rate (moderate and vigorous intensity).

  15. Differences in foot kinematics between young and older adults during walking.

    Science.gov (United States)

    Arnold, John B; Mackintosh, Shylie; Jones, Sara; Thewlis, Dominic

    2014-02-01

    Our understanding of age-related changes to foot function during walking has mainly been based on plantar pressure measurements, with little information on differences in foot kinematics between young and older adults. The purpose of this study was to investigate the differences in foot kinematics between young and older adults during walking using a multi-segment foot model. Joint kinematics of the foot and ankle for 20 young (mean age 23.2 years, standard deviation (SD) 3.0) and 20 older adults (mean age 73.2 years, SD 5.1) were quantified during walking with a 12 camera Vicon motion analysis system using a five segment kinematic model. Differences in kinematics were compared between older adults and young adults (preferred and slow walking speeds) using Student's t-tests or if indicated, Mann-Whitney U tests. Effect sizes (Cohen's d) for the differences were also computed. The older adults had a less plantarflexed calcaneus at toe-off (-9.6° vs. -16.1°, d = 1.0, p = Walking speed did not influence these differences, as they remained present when groups walked at comparable speeds. The findings of this study indicate that independent of walking speed, older adults exhibit significant differences in foot kinematics compared to younger adults, characterised by less propulsion and reduced mobility of multiple foot segments.

  16. Snell's law and walking droplets

    Science.gov (United States)

    Bush, John; Pucci, Giuseppe; Aubin, Benjamin; Brun, Pierre-Thomas; Faria, Luiz

    2016-11-01

    Droplets walking on the surface of a vibrating bath have been shown to exhibit a number of quantum-like features. We here present the results of a combined experimental and theoretical investigation of such droplets crossing a linear step corresponding to a reduction in bath depth. When the step is sufficiently large, the walker reflects off the step; otherwise, it is refracted as it crosses the step. Particular attention is given to an examination of the regime in which the droplet obeys a form of Snell's Law, a behavior captured in accompanying simulations. Attempts to provide theoretical rationale for the dependence of the effective refractive index on the system parameters are described. Supported by NSF through CMMI-1333242.

  17. Quantum walks and gravitational waves

    Science.gov (United States)

    Arnault, Pablo; Debbasch, Fabrice

    2017-08-01

    A new family of discrete-time quantum walks (DTQWs) propagating on a regular (1 + 2)D spacetime lattice is introduced. The continuum limit of these DTQWs is shown to coincide with the dynamics of a Dirac fermion coupled to an arbitrary relativistic gravitational field. This family is used to model the influence of arbitrary linear gravitational waves (GWs) on DTQWs. Pure shear GWs are studied in detail. We show that on large spatial scales, the spatial deformation generated by the wave induces a rescaling of the eigen-energies by a certain anisotropic factor which can be computed exactly. The effect of pure shear GWs on fermion interference patterns is also investigated, both on large scales and on scales comparable to the lattice spacing.

  18. Walking droplets in confined geometries

    Science.gov (United States)

    Filoux, Boris; Mathieu, Olivier; Vandewalle, Nicolas

    2014-11-01

    When gently placing a droplet onto a vertically vibrated bath, coalescence may be avoided: the drop bounces permanently. Upon increasing forcing acceleration, a drop interacts with the wave it generates, and becomes a ``walker'' with a well defined velocity. In this work, we investigate the confinement of a walker in a mono-dimensional geometry. The system consists of linear submarine channels used as waveguides for a walker. By studying the dynamics of walkers in those channels, we discover some 1D-2D transition. We also propose a model based on an analogy with ``Quantum Wires.'' Finally, we consider the situation of a walker in a circular submarine channel, and examine the behavior of several walking droplets in this system. We show the quantization of the drop distances, and correlate it to their bouncing modes.

  19. Recurrence in coined quantum walks

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, T; Kecskes, L [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Konkoly-Thege M. u. 29-33, H-1121 Budapest (Hungary); Stefanak, M; Jex, I [Department of Physics, FJFI CVUT v Praze, Brehova 7, 115 19 Praha 1-Stare Mesto (Czech Republic)], E-mail: tkiss@szfki.hu

    2009-07-15

    Recurrence of quantum walks on lattices can be characterized by the generalized Polya number. Its value reflects the difference between a classical and a quantum system. The dimension of the lattice is not a unique parameter in the quantum case; both the coin operator and the initial quantum state of the coin influence the recurrence in a nontrivial way. In addition, the definition of the Polya number involves measurement of the system. Depending on how measurement is included in the definition, the recurrence properties vary. We show that in the limiting case of frequent, strong measurements, one can approach the classical dynamics. Comparing various cases, we have found numerical indication that our previous definition of the Polya number provides an upper limit.

  20. Symbolic walk in regular networks

    Science.gov (United States)

    Ermann, Leonardo; Carlo, Gabriel G.

    2015-01-01

    We find that a symbolic walk (SW)—performed by a walker with memory given by a Bernoulli shift—is able to distinguish between the random or chaotic topology of a given network. We show this result by means of studying the undirected baker network, which is defined by following the Ulam approach for the baker transformation in order to introduce the effect of deterministic chaos into its structure. The chaotic topology is revealed through the central role played by the nodes associated with the positions corresponding to the shortest periodic orbits of the generating map. They are the overwhelmingly most visited nodes in the limit cycles at which the SW asymptotically arrives. Our findings contribute to linking deterministic chaotic dynamics with the properties of networks constructed using the Ulam approach.

  1. Blindman-Walking Optimization Method

    Directory of Open Access Journals (Sweden)

    Chunming Li

    2010-12-01

    Full Text Available Optimization methods are all implemented with the hypothesis of unknowing the mathematic express of objective objection. Using the human analogy innovative method, the one-dimension blind-walking optimal method is proposed in this paper. The theory and the algorithm of this method includes halving, doubling, reversing probing step and verifying the applicability condition. Double-step is available to make current point moving to the extremum point. Half-step is available to accelerate convergence. In order to improve the optimization, the applicability condition decides whether update current point or not. The operation process, algorithmic flow chart and characteristic analysis of the method were given. Two optimization problems with unimodal or multimodal objective function were solved by the proposed method respectively. The simulation result shows that the proposed method is better than the ordinary method. The proposed method has the merit of rapid convergence, little calculation capacity, wide applicable range, etc. Taking the method as innovative kernel, the random research method, feasible direction method and complex shape method were improved. Taking the innovative content of this paper as innovative kernel, a monograph was published. The other innovations of the monograph are listed, such as applied algorithm of Karush-Kuhn-Tucker (KKT qualifications on judging the restriction extremum point, the design step of computing software, the complementarity and derivation of Powell criterion, the method of keeping the complex shape not to deduce dimension and the analysis of gradual optimization characteristic, the reinforced wall of inner point punish function method, the analysis of problem with constrained monstrosity extremum point, the improvement of Newton method and the validation of optimization idea of blind walking repeatedly, the explanation of later-day optimization method, the conformity of seeking algorithm needing the

  2. Uphill and Downhill Walking in Multiple Sclerosis: A Randomized Controlled Trial.

    Science.gov (United States)

    Samaei, Afshin; Bakhtiary, Amir Hoshang; Hajihasani, Abdolhamid; Fatemi, Elham; Motaharinezhad, Fatemeh

    2016-01-01

    Various exercise protocols have been recommended for patients with multiple sclerosis (MS). We investigated the effects of uphill and downhill walking exercise on mobility, functional activities, and muscle strength in MS patients. Thirty-four MS patients were randomly allocated to either the downhill or uphill treadmill walking group for 12 sessions (3 times/wk) of 30 minutes' walking on a 10% negative slope (n = 17) or a 10% positive slope (n = 17), respectively. Measurements were taken before and after the intervention and after 4-week follow-up and included fatigue by Modified Fatigue Impact Scale; mobility by Modified Rivermead Mobility Index; disability by Guy's Neurological Disability Scale; functional activities by 2-Minute Walk Test, Timed 25-Foot Walk test, and Timed Up and Go test; balance indices by Biodex Balance System; and quadriceps and hamstring isometric muscles by torque of left and right knee joints. Analysis of variance with repeated measures was used to investigate the intervention effects on the measurements. After the intervention, significant improvement was found in the downhill group versus the uphill group in terms of fatigue, mobility, and disability indices; functional activities; balance indices; and quadriceps isometric torque (P < .05). The results were stable at 4-week follow-up. Downhill walking on a treadmill may improve muscle performance, functional activity, and balance control in MS patients. These findings support the idea of using eccentric exercise training in MS rehabilitation protocols.

  3. Differences in muscle activity and temporal step parameters between Lokomat guided walking and treadmill walking in post-stroke hemiparetic patients and healthy walkers.

    Science.gov (United States)

    van Kammen, Klaske; Boonstra, Anne M; van der Woude, Lucas H V; Reinders-Messelink, Heleen A; den Otter, Rob

    2017-04-20

    The Lokomat is a robotic exoskeleton that can be used to train gait function in hemiparetic stroke. To purposefully employ the Lokomat for training, it is important to understand (1) how Lokomat guided walking affects muscle activity following stroke and how these effects differ between patients and healthy walkers, (2) how abnormalities in the muscle activity of patients are modulated through Lokomat guided gait, and (3) how temporal step characteristics of patients were modulated during Lokomat guided walking. Ten hemiparetic stroke patients (>3 months post-stroke) and ten healthy age-matched controls walked on the treadmill and in the Lokomat (guidance force 50%, no bodyweight support) at matched speeds (0.56 m/s). Electromyography was used to record the activity of Gluteus Medius, Biceps Femoris, Vastus Lateralis, Medial Gastrocnemius and Tibialis Anterior, bilaterally in patients and of the dominant leg in healthy walkers. Pressure sensors placed in the footwear were used to determine relative durations of the first double support and the single support phases. Overall, Lokomat guided walking was associated with a general lowering of muscle activity compared to treadmill walking, in patients as well as healthy walkers. The nature of these effects differed between groups for specific muscles, in that reductions in patients were larger if muscles were overly active during treadmill walking (unaffected Biceps Femoris and Gluteus Medius, affected Biceps Femoris and Vastus Lateralis), and smaller if activity was already abnormally low (affected Medial Gastrocnemius). Also, Lokomat guided walking was associated with a decrease in asymmetry in the relative duration of the single support phase. In stroke patients, Lokomat guided walking results in a general reduction of muscle activity, that affects epochs of overactivity and epochs of reduced activity in a similar fashion. These findings should be taken into account when considering the clinical potential of the

  4. Preliminary study of novel, timed walking tests for children with spina bifida or cerebral palsy

    Science.gov (United States)

    Kane, Kyra J; Lanovaz, Joel; Bisaro, Derek; Oates, Alison; Musselman, Kristin E

    2016-01-01

    Objective: Walking assessment is an important aspect of rehabilitation practice; yet, clinicians have few psychometrically sound options for evaluating walking in highly ambulatory children. The purpose of this study was to evaluate the validity and reliability of two new measures of walking function—the Obstacles and Curb tests—relative to the 10-Meter Walk test and Timed Up and Go test in children with spina bifida or cerebral palsy. Methods: A total of 16 ambulatory children with spina bifida (n=9) or cerebral palsy (n=7) (9 boys; mean age 7years, 7months; standard deviation 3years, 4months) and 16 age- and gender-matched typically developing children participated. Children completed the walking tests, at both self-selected and fast speeds, twice. To evaluate discriminative validity, scores were compared between typically developing and spina bifida/cerebral palsy groups. Within the spina bifida/cerebral palsy group, inter-test correlations evaluated convergent validity and intraclass correlation coefficients evaluated within-session test–retest reliability. Results: At fast speeds, all tests showed discriminative validity (p<0.006 for typically developing and spina bifida/cerebral palsy comparisons) and convergent validity (rho=0.81–0.90, p⩽0.001, for inter-test correlations). At self-selected speeds, only the Obstacles test discriminated between groups (p=0.001). Moderately strong correlations (rho=0.73–0.78, p⩽0.001) were seen between the 10-Meter Walk test, Curb test, and Timed Up and Go test. Intraclass correlation coefficients ranged from 0.81 to 0.97, with higher test–retest reliability for tests performed at fast speeds rather than self-selected speeds. Conclusion: The Obstacles and Curb tests are promising measures for assessing walking in this population. Performing tests at fast walking speeds may improve their validity and test–retest reliability for children with spina bifida/cerebral palsy. PMID:27493754

  5. IMPACT OF BODY WEIGHT SUPPORTED BACKWARD TREADMILL TRAINING ON WALKING SPEED IN CHILDREN WITH SPASTIC DIPLEGIA

    Directory of Open Access Journals (Sweden)

    Hamada El Sayed Abd Allah Ayoub

    2016-10-01

    Full Text Available Background: A lot of the ambulating children with spastic diplegia were able to walk with flexed hips, knees and ankles this gait pattern is known as crouch gait. The most needed functional achievement of diplegic children habilitation is to be able to walk appropriately. The development of an independent and efficient walking is one of the main objectives for children with cerebral palsy especially those with spastic diplegia. Method: Twenty children with spastic diplegia enrolled in this study, they were classified into two groups of equal number, eligibility to our study were ages ranged from seven to ten years, were able to ambulate, They had gait problems and abnormal gait kinematics. The control group (A received selected physical therapy program based on neurodevelopmental approach for such cases, while the study group (B received partial body weight supported backward treadmill training in addition to regular exercise program. Gait pattern was assessed using the Biodex Gait Trainer II for each group pre and post three months of the treatment program. Results: There was statistically significant improvement in walking speed in the study group (P<0.05 with significant difference when comparing post treatment results between groups (p<0.05. Conclusion: These findings suggested that partial body weight supported backward treadmill training can be included as a supplementary therapeutic modality to improve walking speed and functional abilities of children with diplegic cerebral palsy.

  6. A STUDY TO COMPARE THE EFFECTIVENESS OF TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION WITH RETRO - WALKING VERSUS ULTRASOUND THERAPY WITH RETRO - WALKING IN CHRONIC OSTEOARTHRITIS OF KNEE

    Directory of Open Access Journals (Sweden)

    Somashekar

    2015-07-01

    Full Text Available BACKGROUND AND OBJECTIVES: Knee osteoarthritis (OA is a painful and degenerative joint diseases, the pain, joint stiffness associated with this condition have a dramatic impact on physical mobility and function. This study was done to assess the effectiveness of TENS and retro walking versus ultrasound therapy with retro walking in patients suffering from chronic knee osteoarthritis. METHODS: All the subjects were clinically diagnosed by orthopaedician with chronic knee osteoarthritis were screen ed after finding their suitability as per the inclusion criteria and were requested to participate in the study. Participants in the study were briefed about the nature of the study and their intervention. After briefing them about the study, their informe d written consent was taken. 60 chronic knee osteoarthritis patient were randomly divided into two groups with n=30 in each group, Group A - received TENS transcutaneous electrical nerve stimulation and retro walking, where group B - received ultrasound therap y with retro walking. The treatment was given 5 days a week. The total duration of treatment was 3 weeks. OUTCOMES MEASURES: The patie n ts were evaluated at the beginning of the intervention program, Day 1st, end of 1st week, end of 2nd week and end of 3rd week. All the Patients were requested to come for a follow up measurement after 3rd week of treatment program. All the patients were assessed for pain, functional outcome and range of motion by taking their VAS scale, WOMAC scale and universal goniometer. RESULTS: Both the groups showed statistically significant improvement in all three parameters (VAS, WOMAC and Range of motion by repeated test ANOVA. Independent t - test analysis of outcome measures when compared between the two groups showed that Group B outcome measures were significantly far better than the outcome measures of Group A. CONCLUSION: Transcutaneous electrical nerve stimulation TENS with retro walking and therapeutic

  7. Walking dreams in congenital and acquired paraplegia.

    Science.gov (United States)

    Saurat, Marie-Thérèse; Agbakou, Maité; Attigui, Patricia; Golmard, Jean-Louis; Arnulf, Isabelle

    2011-12-01

    To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4-64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep.

  8. The work of walking: a calorimetric study.

    Science.gov (United States)

    Webb, P; Saris, W H; Schoffelen, P F; Van Ingen Schenau, G J; Ten Hoor, F

    1988-08-01

    Experiments were designed to test the traditional assumption that during level walking all of the energy from oxidation of fuel appears as heat and no work is done. Work is force expressed through distance, or energy transferred from a man to the environment, but not as heat. While wearing a suit calorimeter in a respiration chamber, five women and five men walked for 70 to 90 min on a level treadmill at 2.5, 4.6, and 6.7 km.h-1 and pedalled a cycle ergometer for 70 to 90 min against 53 and 92 W loads. They also walked with a weighted backpack and against a horizontal load. During cycling, energy from fuel matched heat loss plus the power measured by the ergometer. During walking, however, energy from fuel exceeded that which appeared as heat, meaning that work was done. The power increased with walking speed; values were 14, 29, and 63 W, which represented 11, 12, and 13% of the incremental cost of fuel above the resting level. Vertical and horizontal loads increased the fuel cost and heat loss of walking but did not alter the power output. This work energy did not re-appear as thermal energy during 18 h of recovery. The most likely explanation of the work done is in the inter-action between the foot and the ground, such as compressing the heel of the shoe and bending the sole. We conclude that work is done in level walking.

  9. The Walking Renaissance: A Longitudinal Analysis of Walking Travel in the Greater Los Angeles Area, USA

    Directory of Open Access Journals (Sweden)

    Kenneth Joh

    2015-07-01

    Full Text Available Promoting walking travel is considered important for reducing automobile use and improving public health. Recent U.S. transportation policy has incentivized investments in alternative, more sustainable transportation modes such as walking, bicycling and transit in auto-oriented cities such as Los Angeles. Although many past studies have analyzed changes in walking travel across the U.S., there is little clarity on the drivers of change. We address this gap by conducting a longitudinal analysis of walking travel in the greater Los Angeles area from 2001 to 2009. We use travel diary and household data from regional and national surveys to analyze changes in walking trip shares and rates across our study area. Results show that walking has significantly increased across most of Los Angeles, and that increases in walking trips generally correspond with increases in population, employment, and transit service densities. Estimates from fixed-effects regression analysis generally suggest a positive association between population density and walking, and that higher increases in transit stop density are correlated with increased walking trips to and from transit stops. These findings illustrate how regional planning efforts to pursue a coordinated land use-transit planning strategy can help promote walking in auto-oriented or vehicle adopting cities.

  10. Effects of proprioceptive sense-based Kinesio taping on walking imbalance.

    Science.gov (United States)

    Park, Young-Han; Lee, Jung-Ho

    2016-11-01

    [Purpose] The aim of this study was to determine how application of Kinesio tape to the upper and lower limbs affects walking through stimulation of the proprioceptive sense. [Subjects and Methods] Twelve patients diagnosed with hemiplegia due to stroke were selected as the subjects of the study. To ascertain the effects of Kinesio taping on walking, all subjects performed a straight line walking test three times while barefoot. In terms of the actual taping application, elastic Kinesio tape was used on the hemiplegic side in all subjects. [Results] The results of testing showed a significant difference in the values between before and after taping. In terms of left and right deviation according to the site of the taping application, there were statistically significant differences among the groups. [Conclusion] In conclusion, application of Kinesio taping for central nerve injury was confirmed to be effective in reducing walking deviation.

  11. Quantum walk public-key cryptographic system

    Science.gov (United States)

    Vlachou, C.; Rodrigues, J.; Mateus, P.; Paunković, N.; Souto, A.

    2015-12-01

    Quantum Cryptography is a rapidly developing field of research that benefits from the properties of Quantum Mechanics in performing cryptographic tasks. Quantum walks are a powerful model for quantum computation and very promising for quantum information processing. In this paper, we present a quantum public-key cryptographic system based on quantum walks. In particular, in the proposed protocol the public-key is given by a quantum state generated by performing a quantum walk. We show that the protocol is secure and analyze the complexity of public key generation and encryption/decryption procedures.

  12. An experimental analysis of human straight walking

    Science.gov (United States)

    Li, Tao; Ceccarelli, Marco

    2013-03-01

    In this paper, an experimental analysis of human straight walking has been presented. Experiments on human walking were carried out by using Cassino tracking system which is a passive cable-based measuring system. This system is adopted because it is capable of both pose and wrench measurements with fairly simple monitoring of operation. By using experimental results, trajectories of a human limb extremity and its posture have been analyzed; forces that are exerted against cables by the limb of a person under test have been measured by force sensors as well. Furthermore, by using experimental tests, modeling and characterization of the human straight walking gait have been proposed.

  13. Elements of random walk and diffusion processes

    CERN Document Server

    Ibe, Oliver C

    2013-01-01

    Presents an important and unique introduction to random walk theory Random walk is a stochastic process that has proven to be a useful model in understanding discrete-state discrete-time processes across a wide spectrum of scientific disciplines. Elements of Random Walk and Diffusion Processes provides an interdisciplinary approach by including numerous practical examples and exercises with real-world applications in operations research, economics, engineering, and physics. Featuring an introduction to powerful and general techniques that are used in the application of physical and dynamic

  14. Limit cycle walking on a regularized ground

    CERN Document Server

    Jacobs, Henry O

    2012-01-01

    The singular nature of contact problems, such as walking, makes them difficult to analyze mathematically. In this paper we will "regularize" the contact problem of walking by approximating the ground with a smooth repulsive potential energy and a smooth dissipative friction force. Using this model we are able to prove the existence of a limit cycle for a periodically perturbed system which consists of three masses connected by springs. In particular, this limit cycle exists in a symmetry reduced phase. In the unreduced phase space, the motion of the masses resembles walking.

  15. [Walking assist robot and its clinical application].

    Science.gov (United States)

    Kakou, Hiroaki; Shitama, Hideo; Kimura, Yoshiko; Nakamoto, Yoko; Furuta, Nami; Honda, Kanae; Wada, Futoshi; Hachisuka, Kenji

    2009-06-01

    The walking assist robot was developed to improve gait disturbance in patients with severe disabilities. The robot had a trunk supporter, power generator and operating arms which held patient's lower extremities and simulated walking, a control unit, biofeedback system, and a treadmill. We applied the robot-aided gait training to three patients with severe gait disturbance induced by stroke, axonal Guillan-Barré syndrome or spinal cord injury, and the walking assist robot turned out to be effective in improving the gait disturbance.

  16. Scaling of random walk betweenness in networks

    CERN Document Server

    Narayan, O

    2016-01-01

    The betweenness centrality of graphs using random walk paths instead of geodesics is studied. A scaling collapse with no adjustable parameters is obtained as the graph size $N$ is varied; the scaling curve depends on the graph model. A normalized random betweenness, that counts each walk passing through a node only once, is also defined. It is argued to be more useful and seen to have simpler scaling behavior. In particular, the probability for a random walk on a preferential attachment graph to pass through the root node is found to tend to unity as $N\\rightarrow\\infty.$

  17. Exponential algorithmic speedup by quantum walk

    CERN Document Server

    Childs, A M; Deotto, E; Farhi, E; Gutmann, S; Spielman, D A; Childs, Andrew M.; Cleve, Richard; Deotto, Enrico; Farhi, Edward; Gutmann, Sam; Spielman, Daniel A.

    2002-01-01

    We construct an oracular problem that can be solved exponentially faster on a quantum computer than on a classical computer. The quantum algorithm is based on a continuous time quantum walk, and thus employs a different technique from previous quantum algorithms based on quantum Fourier transforms. We show how to implement the quantum walk efficiently in our oracular setting. We then show how this quantum walk can be used to solve our problem by rapidly traversing a graph. Finally, we prove that no classical algorithm can solve this problem with high probability in subexponential time.

  18. Effect of Backward Walking Training on Improves Postural Stability in Children with Down syndrome

    Directory of Open Access Journals (Sweden)

    Hojat Allah Amini

    2016-07-01

    Full Text Available Background Motor intervention plays an important role in reducing the disabilities of Down syndrome (DS. A lack of balance and postural control has created motor problems in DS patients. Therefore, the aim of this study was to examine the effect of backward walking on postural stability of DS patients. Materials and Methods Sixteen DS children with 8-10 age range were selected by convenience sampling method and assigned to control and experimental groups. The experimental group performed backward walking training for 8 weeks (2 sessions per week, each session for 25 min. The dynamic postural stability of both groups was examined by Biodex stability system (general balance, medial collateral and anterior-posterior balance indexes before, during and after the training (pretest, 4th week, 8th week and 18th week. To analyze the data and test the hypotheses, independent t test was used. Results The results of this study showed that the three balance indexes in the experimental group was drastically lower than the control group after 8 weeks of backward walking training (P˂0.01. In addition, significant differences could be observed in balance indexes even 10 weeks after the last session of the backward walking training (P˂0.05. Conclusion It seems that the findings of this study have confirmed the effect of backward walking training on the improvement of postural stability and Syndrome children with 8-10 age range can benefit from this method.

  19. Nordic Walking and chronic low back pain: design of a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Hartvigsen Jan

    2006-10-01

    Full Text Available Abstract Background Low Back Pain is a major public health problem all over the western world. Active approaches including exercise in the treatment of low back pain results in better outcomes for patients, but it is not known exactly which types of back exercises are most beneficial or whether general physical activity provide similar benefits. Nordic Walking is a popular and fast growing type of exercise in Northern Europe. Initial studies have demonstrated that persons performing Nordic Walking are able to exercise longer and harder compared to normal walking thereby increasing their cardiovascular metabolism. Until now no studies have been performed to investigate whether Nordic Walking has beneficial effects in relation to low back pain. The primary aim of this study is to investigate whether supervised Nordic Walking can reduce pain and improve function in a population of chronic low back pain patients when compared to unsupervised Nordic Walking and advice to stay active. In addition we investigate whether there is an increase in the cardiovascular metabolism in persons performing supervised Nordic Walking compared to persons who are advised to stay active. Finally, we investigate whether there is a difference in compliance between persons receiving supervised Nordic Walking and persons doing unsupervised Nordic Walking. Methods One hundred and fifty patients with low back pain for at least eight weeks and referred to a specialized secondary sector outpatient back pain clinic are included in the study. After completion of the standard back centre treatment patients are randomized into one of three groups: A Nordic Walking twice a week for eight weeks under supervision of a specially trained instructor; B Unsupervised Nordic Walking for eight weeks after one training session with an instructor; C A one hour motivational talk including advice to stay active. Outcome measures are pain, function, overall health, cardiovascular ability and

  20. Stakeholder perceptions of a nurse led walk-in centre

    Directory of Open Access Journals (Sweden)

    Parker Rhian M

    2012-11-01

    Full Text Available Abstract Background As many countries face primary care medical workforce shortages and find it difficult to provide timely and affordable care they seek to find new ways of delivering first point of contact health care through developing new service models. In common with other areas of rural and regional Australia, the Australian Capital Territory (ACT is currently experiencing a general practitioner (GP workforce shortage which impacts significantly on the ability of patients to access GP led primary care services. The introduction of a nurse led primary care Walk-in Centre in the ACT aimed to fulfill an unmet health care need in the community and meet projected demand for health care services as well as relieve pressure on the hospital system. Stakeholders have the potential to influence health service planning and policy, to advise on the potential of services to meet population health needs and to assess how acceptable health service innovation is to key stakeholder groups. This study aimed to ascertain the views of key stakeholders about the Walk-in Centre. Methods Stakeholders were purposively selected through the identification of individuals and organisations which had organisational or professional contact with the Walk-in Centre. Semi structured interviews around key themes were conducted with seventeen stakeholders. Results Stakeholders were generally supportive of the Walk-in Centre but identified key areas which they considered needed to be addressed. These included the service's systems, full utilisation of the nurse practitioner role and adequate education and training. It was also suggested that a doctor could be available to the Centre as a source of referral for patients who fall outside the nurses' scope of practice. The location of the Centre was seen to impact on patient flows to the Emergency Department. Conclusion Nurse led Walk-in Centres are one response to addressing primary health care medical workforce shortages

  1. Design of a walking robot

    Science.gov (United States)

    Whittaker, William; Dowling, Kevin

    1994-01-01

    Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

  2. Holographic walking from tachyon DBI

    Energy Technology Data Exchange (ETDEWEB)

    Kutasov, David [EFI and Department of Physics, University of Chicago, 5640 S. Ellis Av., Chicago, IL 60637 (United States); Lin, Jennifer, E-mail: jenlin@uchicago.edu [EFI and Department of Physics, University of Chicago, 5640 S. Ellis Av., Chicago, IL 60637 (United States); Parnachev, Andrei [Institute Lorentz for Theoretical Physics, Leiden University, PO Box 9506, Leiden 2300RA (Netherlands)

    2012-10-11

    We use holography to study conformal phase transitions, which are believed to be realized in four dimensional QCD and play an important role in walking technicolor models of electroweak symmetry breaking. At strong coupling they can be modeled by the non-linear dynamics of a tachyonic scalar field with mass close to the Breitenlohner-Freedman bound in anti-de Sitter spacetime. Taking the action for this field to have a tachyon-Dirac-Born-Infeld form gives rise to models that resemble hard and soft wall AdS/QCD, with a dynamically generated wall. For hard wall models, the highly excited spectrum has the KK form m{sub n}{approx}n; in the soft wall case we exhibit potentials with m{sub n}{approx}n{sup {alpha}}, 0<{alpha} Less-Than-Or-Slanted-Equal-To 1/2. We investigate the finite temperature phase structure and find first or second order symmetry restoration transitions, depending on the behavior of the potential near the origin of field space.

  3. Locomotor sequence learning in visually guided walking

    DEFF Research Database (Denmark)

    Choi, Julia T; Jensen, Peter; Nielsen, Jens Bo

    2016-01-01

    walking. In addition, we determined how age (i.e., healthy young adults vs. children) and biomechanical factors (i.e., walking speed) affected the rate and magnitude of locomotor sequence learning. The results showed that healthy young adults (age 24 ± 5 years, N = 20) could learn a specific sequence...... of step lengths over 300 training steps. Younger children (age 6-10 years, N = 8) have lower baseline performance, but their magnitude and rate of sequence learning was the same compared to older children (11-16 years, N = 10) and healthy adults. In addition, learning capacity may be more limited...... at faster walking speeds. To our knowledge, this is the first study to demonstrate that spatial sequence learning can be integrated with a highly automatic task like walking. These findings suggest that adults and children use implicit knowledge about the sequence to plan and execute leg movement during...

  4. Database of Standardized Questionnaires About Walking & Bicycling

    Science.gov (United States)

    This database contains questionnaire items and a list of validation studies for standardized items related to walking and biking. The items come from multiple national and international physical activity questionnaires.

  5. Second syzygies of monomial submodules from walks

    CERN Document Server

    Craw, Alastair

    2011-01-01

    We present an explicit and especially simple filtration on the module of syzygies of a monomial submodule. Our main tool is the description of generators of the module of second syzygies in terms of walks in a complete graph.

  6. Levy random walks on multiplex networks

    CERN Document Server

    Guo, Quantong; Zheng, Zhiming; Moreno, Yamir

    2016-01-01

    Random walks constitute a fundamental mechanism for many dynamics taking place on complex networks. Besides, as a more realistic description of our society, multiplex networks have been receiving a growing interest, as well as the dynamical processes that occur on top of them. Here, inspired by one specific model of random walks that seems to be ubiquitous across many scientific fields, the Levy flight, we study a new navigation strategy on top of multiplex networks. Capitalizing on spectral graph and stochastic matrix theories, we derive analytical expressions for the mean first passage time and the average time to reach a node on these networks. Moreover, we also explore the efficiency of Levy random walks, which we found to be very different as compared to the single layer scenario, accounting for the structure and dynamics inherent to the multiplex network. Finally, by comparing with some other important random walk processes defined on multiplex networks, we find that in some region of the parameters, a ...

  7. Simple expressions for the long walk distance

    CERN Document Server

    Chebotarev, Pavel; Balaji, R

    2011-01-01

    The walk distances in graphs are defined as the result of appropriate transformations of the $\\sum_{k=0}^\\infty(tA)^k$ proximity measures, where $A$ is the weighted adjacency matrix of a connected weighted graph and $t$ is a sufficiently small positive parameter. The walk distances are graph-geodetic, moreover, they converge to the shortest path distance and to the so-called long walk distance as the parameter $t$ approaches its limiting values. In this paper, simple expressions for the long walk distance are obtained. They involve the generalized inverse, minors, and inverses of submatrices of the symmetric irreducible singular M-matrix ${\\cal L}=\\rho I-A,$ where $\\rho$ is the Perron root of $A.$

  8. Sensitivity Study of Stochastic Walking Load Models

    DEFF Research Database (Denmark)

    Pedersen, Lars; Frier, Christian

    2010-01-01

    On flexible structures such as footbridges and long-span floors, walking loads may generate excessive structural vibrations and serviceability problems. The problem is increasing because of the growing tendency to employ long spans in structural design. In many design codes, the vibration...... serviceability limit state is assessed using a walking load model in which the walking parameters are modelled deterministically. However, the walking parameters are stochastic (for instance the weight of the pedestrian is not likely to be the same for every footbridge crossing), and a natural way forward...... investigates whether statistical distributions of bridge response are sensitive to some of the decisions made by the engineer doing the analyses. For the paper a selected part of potential influences are examined and footbridge responses are extracted using Monte-Carlo simulations and focus is on estimating...

  9. Symmetricity of Distribution for One-Dimensional Hadamard Walk

    CERN Document Server

    Konno, N; Soshi, T; Konno, Norio; Namiki, Takao; Soshi, Takahiro

    2002-01-01

    In this paper we study a one-dimensional quantum random walk with the Hadamard transformation which is often called the Hadamard walk. We construct the Hadamard walk using a transition matrix on probability amplitude and give some results on symmetricity of probability distributions for the Hadamard walk.

  10. Variability and stability analysis of walking of transfemoral amputees

    NARCIS (Netherlands)

    Lamoth, Claudine C.; Ainsworth, Erik; Polomski, Wojtek; Houdijk, Han

    2010-01-01

    Variability and stability of walking of eight transfemoral amputees and eight healthy controls was studied under four conditions walking inside on a smooth terrain walking while performing a dual-task and walking outside on (ir)regular surfaces Trunk accelerations were recorded with a tri-axial acce

  11. Urban Walking and the Pedagogies of the Street

    Science.gov (United States)

    Bairner, Alan

    2011-01-01

    Drawing upon the extensive literature on urban walking and also on almost 60 years' experience of walking the streets, this article argues that there is a pressing need to re-assert the educational value of going for a walk. After a brief discussion of the social significance of the "flaneur," the historic pioneer of urban walking, the article…

  12. Does getting a dog increase recreational walking?

    Directory of Open Access Journals (Sweden)

    Knuiman Matthew W

    2008-03-01

    Full Text Available Abstract Background This study examines changes in socio-demographic, environmental and intrapersonal factors associated with dog acquisition in non-dog owners at baseline to 12-months follow-up and the effect of dog acquisition on minutes per week of recreational walking. Methods RESIDE study participants completed self-administered questionnaires (baseline and 12-months follow-up measuring physical activity, dog ownership, dog walking behavior as well as environmental, intrapersonal and socio-demographic factors. Analysis was restricted to 'Continuing non-owners' (i.e., non-owners at both baseline and follow-up; n = 681 and 'New dog owners' (i.e., non-owners who acquired a dog by follow-up; n = 92. Results Overall, 12% of baseline non-owners had acquired a dog at follow-up. Dog acquisition was associated with working and having children at home. Those who changed from single to couple marital status were also more likely to acquire a dog. The increase in minutes of walking for recreation within the neighborhood from baseline to follow-up was 48 minutes/week for new dog owners compared with 12 minutes/week for continuing non-owners (p p p > 0.05 after further adjustment for change in baseline to follow-up variables. Increase in intention to walk was the main factor contributing to attenuation of the effect of dog acquisition on recreational walking. Conclusion This study used a large representative sample of non-owners to examine the relationship between dog acquisition and recreational walking and provides evidence to suggest that dog acquisition leads to an increase in walking. The most likely mechanism through which dog acquisition facilitates increased physical activity is through behavioral intention via the dog's positive effect on owner's cognitive beliefs about walking, and through the provision of motivation and social support for walking. The results suggest that behavioral intention mediates the relationship between dog acquisition

  13. Walking as a social practice: dispersed walking and the organisation of everyday practices.

    Science.gov (United States)

    Harries, Tim; Rettie, Ruth

    2016-07-01

    This paper uses social practice theory to study the interweaving of walking into everyday practices and considers how greater awareness of everyday walking can influence its position within the organisation and scheduling of everyday life. Walking is of policy interest because of its perceived benefits for health. This paper asserts that increased awareness of everyday walking allows users to become more active without having to reschedule existing activities. Using Schatzki's distinction between dispersed and integrative practices, it argues that increasing awareness of dispersed walking can enlist walking into the teleoaffective organisation of some social practices and prompt the performance of new 'health practices' within everyday domains of life such as shopping and employment. While this analysis offers useful insights for the design of behaviour change strategies, it also points to some unintended consequences of using digital feedback to increase walking awareness. In directing the gaze of participants at one particular element of their daily practices, the paper suggests, digital walking feedback provides a 'partial' view of practices: by highlighting the exercise value of walking at the expense of other values it can prompt feedback recipients to pass moral judgements on themselves based on this partial view. A Virtual Abstract of this paper can be found at: https://youtu.be/WV7DUnKD5Mw. © 2016 Foundation for the Sociology of Health & Illness.

  14. Walking on high heels changes muscle activity and the dynamics of human walking significantly

    DEFF Research Database (Denmark)

    Simonsen, Erik Bruun; Svendsen, Morten B; Nørreslet, Andreas

    2012-01-01

    digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...... joint abductor moment. Several EMG parameters increased significantly when walking on high-heels. The results indicate a large increase in bone-on-bone forces in the knee joint directly caused by the increased knee joint extensor moment during high-heeled walking, which may explain the observed higher...

  15. The Snail Takes a Walk with Me

    Institute of Scientific and Technical Information of China (English)

    王宜鸣; 乐伟国

    2008-01-01

    @@ 一、故事内容 I'm a snake. Today God gives me a job-I should take a walk with the snail. The snail moves too slowly. I have to scare him. He looks at me, full of shame. I am very angry. I pull him, and even kick.The snail cries, so he stops walking. I feel quite helpless.

  16. On a directionally reinforced random walk

    CERN Document Server

    Ghosh, Arka; Roitershtein, Alexander

    2011-01-01

    We consider a generalized version of a directionally reinforced random walk, which was originally introduced by Mauldin, Monticino, and von Weizs\\"{a}cker in \\cite{drw}. Our main result is a stable limit theorem for the position of the random walk in higher dimensions. This extends a result of Horv\\'{a}th and Shao \\cite{limits} that was previously obtained in dimension one only (however, in a more stringent functional form).

  17. Feedback control system for walking in man.

    Science.gov (United States)

    Petrofsky, J S; Phillips, C A; Heaton, H H

    1984-01-01

    A computer control stimulation system is described which has been successfully tested by allowing a paraplegic subject to stand and walk through closed loop control. This system is a Z80 microprocessor system with eight channels of analog to digital and 16 channels of digital to analog control. Programming is written in CPM and works quite successfully for maintaining lower body postural control in paraplegics. Further expansion of this system would enable a feedback control system for multidirectional walking in man.

  18. Strongly Correlated Quantum Walks in Optical Lattices

    OpenAIRE

    Preiss, Philipp M.; Ma, Ruichao; Tai, M. Eric; Lukin, Alexander; Rispoli, Matthew; Zupancic, Philip; Lahini, Yoav; Islam, Rajibul; Greiner, Markus

    2014-01-01

    Full control over the dynamics of interacting, indistinguishable quantum particles is an important prerequisite for the experimental study of strongly correlated quantum matter and the implementation of high-fidelity quantum information processing. Here we demonstrate such control over the quantum walk - the quantum mechanical analogue of the classical random walk - in the strong interaction regime. Using interacting bosonic atoms in an optical lattice, we directly observe fundamental effects...

  19. More Adults Are Walking PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2012-07-31

    This 60 second PSA is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.  Created: 7/31/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/7/2012.

  20. Go Naked: Diapers Affect Infant Walking

    OpenAIRE

    Cole, Whitney G.; Lingeman, Jesse M.; Adolph, Karen E.

    2012-01-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants’ poor balance and wide stance. We show that walking is adversely affected by old-fashioned cloth diapers, and that even modern disposable diapers—habitually worn by most infants in the sample—incur...

  1. Balancing of the anthropomorphous robot walking

    Science.gov (United States)

    Devaev, V. M.; Nikitina, D. V.; Fadeev, A. Y.

    2016-06-01

    Anthropomorphic robots are designed a human environment operates: buildings and structures, cabs and etc. The movement of these robots is carried out by walking which provides high throughput to overcome natural and manmade obstacles. The article presents some algorithm results for dynamic walking on the anthropomorphic robot AR601 example. The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University.

  2. Factors associated with daily walking of dogs

    OpenAIRE

    Westgarth, Carri; Christian, Hayley E; Christley, Robert M

    2015-01-01

    Background Regular physical activity is beneficial to the health of both people and animals. The role of regular exercise undertaken together, such as dog walking, is a public health interest of mutual benefit. Exploration of barriers and incentives to regular dog walking by owners is now required so that effective interventions to promote it can be designed. This study explored a well-characterised cross-sectional dataset of 276 dogs and owners from Cheshire, UK, for evidence of factors asso...

  3. Walking Out of the Family Towards Rights

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    WALKING in any city or ruralarea in China today, one will seewomen with confidence andpride, with their own work and lives.There is not much difference between theurban and rural women in dress. Theirfaces portray contentment and happiness.These are significant changes which havebeen brought about by women walking outof the family over the past near 50 years,and getting involved in society, alteringtheir dependence on men and making thempeople of dignity. The government knew clearly that to

  4. A Walk in the Semantic Park

    DEFF Research Database (Denmark)

    Danvy, Olivier; Johannsen, Jacob; Zerny, Ian

    2011-01-01

    To celebrate the 20th anniversary of PEPM, we are inviting you to a walk in the semantic park and to inter-derive reduction-based and reduction-free negational normalization functions.......To celebrate the 20th anniversary of PEPM, we are inviting you to a walk in the semantic park and to inter-derive reduction-based and reduction-free negational normalization functions....

  5. Design with the feet: walking methods and participatory design

    DEFF Research Database (Denmark)

    Kanstrup, Anne Marie; Bertelsen, Pernille; Madsen, Jacob Østergaard

    2014-01-01

    This paper presents an analysis of walking methods and their relation to participatory design (PD). The paper includes a study of walking methods found in the literature and an empirical study of transect walks in a PD project. From this analysis, we identify central attributes of, and challenges...... to, PD walks. Walking with people in the context of design is a natural activity for the participatory designer, who acknowledges the importance of immersion and relationships in design. However, the various intentions of walking approaches indicate an underacknowledged awareness of walking methods....... With this study, we take a step towards a methodological framework for "design with the feet" in PD....

  6. Determining asymmetry of roll-over shapes in prosthetic walking

    Directory of Open Access Journals (Sweden)

    Carolin Curtze, MSc

    2011-12-01

    Full Text Available How does the inherent asymmetry of the locomotor system in people with lower-limb amputation affect the ankle-foot roll-over shape of prosthetic walking? In a single-case design, we evaluated the walking patterns of six people with lower-limb amputation (3 transtibial and 3 transfemoral and three matched nondisabled controls. We analyzed the walking patterns in terms of roll-over characteristics and spatial and temporal factors. We determined the level of asymmetry by roll-over shape comparison (root-mean-square distance as well as differences in radius of curvature. In addition, we calculated ratios to determine spatial and temporal asymmetries and described different aspects of asymmetry of roll-over shapes. All participants showed some level of asymmetry in roll-over shape, even the nondisabled controls. Furthermore, we found good intralimb reproducibility for the group as a whole. With respect to spatial and temporal factors, the participants with transtibial amputation had a quite symmetrical gait pattern, while the gait in the participants with transfemoral amputation was more asymmetrical. The individual ankle-foot roll-over shapes provide additional insight into the marked individual adjustments occurring during the stance phase of the nondisabled limb. The two methods we present are suitable for determining asymmetry of roll-over shapes; both methods should be used complementarily.

  7. Ant-inspired density estimation via random walks.

    Science.gov (United States)

    Musco, Cameron; Su, Hsin-Hao; Lynch, Nancy A

    2017-09-19

    Many ant species use distributed population density estimation in applications ranging from quorum sensing, to task allocation, to appraisal of enemy colony strength. It has been shown that ants estimate local population density by tracking encounter rates: The higher the density, the more often the ants bump into each other. We study distributed density estimation from a theoretical perspective. We prove that a group of anonymous agents randomly walking on a grid are able to estimate their density within a small multiplicative error in few steps by measuring their rates of encounter with other agents. Despite dependencies inherent in the fact that nearby agents may collide repeatedly (and, worse, cannot recognize when this happens), our bound nearly matches what would be required to estimate density by independently sampling grid locations. From a biological perspective, our work helps shed light on how ants and other social insects can obtain relatively accurate density estimates via encounter rates. From a technical perspective, our analysis provides tools for understanding complex dependencies in the collision probabilities of multiple random walks. We bound the strength of these dependencies using local mixing properties of the underlying graph. Our results extend beyond the grid to more general graphs, and we discuss applications to size estimation for social networks, density estimation for robot swarms, and random walk-based sampling for sensor networks.

  8. Level walking in adults with and without Developmental Coordination Disorder: An analysis of movement variability.

    Science.gov (United States)

    Du, Wenchong; Wilmut, Kate; Barnett, Anna L

    2015-10-01

    Several studies have shown that Developmental Coordination Disorder (DCD) is a condition that continues beyond childhood. Although adults with DCD report difficulties with dynamic balance, as well as frequent tripping and bumping into objects, there have been no specific studies on walking in this population. Some previous work has focused on walking in children with DCD but variation in the tasks and measures used has led to inconsistent findings. The aim of the current study therefore was to examine the characteristics of level walking in adults with and without DCD. Fifteen adults with DCD and 15 typically developing (TD) controls walked barefoot at a natural pace up and down an 11 m walkway for one minute. Foot placement measures and velocity and acceleration of the body were recorded, as well as measures of movement variability. The adults with DCD showed similar gait patterns to the TD group in terms of step length, step width, double support time and stride time. The DCD group also showed similar velocity and acceleration to the TD group in the medio-lateral, anterior-posterior and vertical direction. However, the DCD group exhibited greater variability in all foot placement and some body movement measures. The finding that adults with DCD have a reduced ability to produce consistent movement patterns is discussed in relation to postural control limitations and compared to variability of walking measures found in elderly populations.

  9. Adaptations to walking on an uneven terrain for individuals with and without Developmental Coordination Disorder.

    Science.gov (United States)

    Gentle, J; Barnett, A L; Wilmut, K

    2016-10-01

    Given the importance of walking in everyday life, understanding why this is challenging for some populations is particularly important. Studies focusing on gait patterns of individuals with Developmental Coordination Disorder (DCD) have shown that whilst increased variability is characteristic of walking patterns for this group, differences in spatio-temporal gait variables seem only to arise when task demands increase. However, these differences occur under rather artificial conditions, for example using a treadmill. The aim of this study, therefore was to examine the step characteristics of individuals with and without DCD whilst walking along an irregular terrain. Thirty-five individuals with DCD aged 8-32years and 35 age and gender-matched controls participated in this study. Participants were divided into 3 age groups; 8-12years (n=12), 13-17years (n=12) and 18-32years (n=11). Participants walked up and down a 6m walkway for two minutes on two terrains: level and irregular. VICON 3D motion analysis was used to extract measures of foot placement, velocity and angle of the head and trunk. Results showed that both groups adapted their gait to negotiate the irregular terrain, but the DCD group was more affected than their TD peers; walking significantly slower with shorter, wider steps and inclining their head more towards the ground. This suggests an adaptive approach used by individuals with DCD to preserve stability and increase visual sampling whilst negotiating an irregular terrain.

  10. Does unilateral transtibial amputation lead to greater metabolic demand during walking?

    Directory of Open Access Journals (Sweden)

    Elizabeth Russell Esposito, PhD

    2015-01-01

    Full Text Available Previous literature reports greater metabolic demand of walking following transtibial amputation. However, most research focuses on relatively older, less active, and often dysvascular amputees. Servicemembers with traumatic amputation are typically young, fit, and highly active before and often following surgical amputation of their lower limb. This study compared the metabolic demand of walking in young, active individuals with traumatic unilateral transtibial amputation (TTA and nondisabled controls. Heart rate (HR, rate of oxygen consumption, and rating of perceived exertion (RPE were calculated as subjects walked at a self-selected velocity and at five standardized velocities based on leg length. The TTA group completed a Prosthetics Evaluation Questionnaire. Oxygen consumption (p = 0.89, net oxygen consumption (p = 0.32, and RPE (p = 0.14 did not differ between groups. Compared with controls, HR was greater in the TTA group and increased to a greater extent with velocity (p < 0.001. Overall, the TTA group rated their walking abilities as high (mean: 93% out of 100%. This is the first study to report equivalent metabolic demand between persons with amputation and controls walking at the same velocity. These results may reflect the physical fitness of the young servicemembers with traumatic amputations and may serve to guide outcome expectations in the future.

  11. Calcaneal loading during walking and running

    Science.gov (United States)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  12. Levy Walks Suboptimal under Predation Risk.

    Directory of Open Access Journals (Sweden)

    Masato S Abe

    2015-11-01

    Full Text Available A key challenge in movement ecology is to understand how animals move in nature. Previous studies have predicted that animals should perform a special class of random walks, called Lévy walk, to obtain more targets. However, some empirical studies did not support this hypothesis, and the relationship between search strategy and ecological factors is still unclear. We focused on ecological factors, such as predation risk, and analyzed whether Lévy walk may not be favored. It was remarkable that the ecological factors often altered an optimal search strategy from Lévy walk to Brownian walk, depending on the speed of the predator's movement, density of predators, etc. This occurred because higher target encounter rates simultaneously led searchers to higher predation risks. Our findings indicate that animals may not perform Lévy walks often, and we suggest that it is crucial to consider the ecological context for evaluating the search strategy performed by animals in the field.

  13. Coined quantum walks on percolation graphs

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Godfrey; Knott, Paul; Bailey, Joe; Kendon, Viv, E-mail: V.Kendon@leeds.ac.uk [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-12-15

    Quantum walks, both discrete (coined) and continuous time, form the basis of several quantum algorithms and have been used to model processes such as transport in spin chains and quantum chemistry. The enhanced spreading and mixing properties of quantum walks compared with their classical counterparts have been well studied on regular structures and also shown to be sensitive to defects and imperfections in the lattice. As a simple example of a disordered system, we consider percolation lattices, in which edges or sites are randomly missing, interrupting the progress of the quantum walk. We use numerical simulation to study the properties of coined quantum walks on these percolation lattices in one and two dimensions. In one dimension (the line), we introduce a simple notion of quantum tunnelling and determine how this affects the properties of the quantum walk as it spreads. On two-dimensional percolation lattices, we show how the spreading rate varies from linear in the number of steps down to zero as the percolation probability decreases towards the critical point. This provides an example of fractional scaling in quantum-walk dynamics.

  14. Winding angles of long lattice walks

    Science.gov (United States)

    Hammer, Yosi; Kantor, Yacov

    2016-07-01

    We study the winding angles of random and self-avoiding walks (SAWs) on square and cubic lattices with number of steps N ranging up to 107. We show that the mean square winding angle of random walks converges to the theoretical form when N → ∞. For self-avoiding walks on the square lattice, we show that the ratio /2 converges slowly to the Gaussian value 3. For self-avoiding walks on the cubic lattice, we find that the ratio /2 exhibits non-monotonic dependence on N and reaches a maximum of 3.73(1) for N ≈ 104. We show that to a good approximation, the square winding angle of a self-avoiding walk on the cubic lattice can be obtained from the summation of the square change in the winding angles of lnN independent segments of the walk, where the ith segment contains 2i steps. We find that the square winding angle of the ith segment increases approximately as i0.5, which leads to an increase of the total square winding angle proportional to (lnN)1.5.

  15. In-home walking speeds and variability trajectories associated with mild cognitive impairment.

    Science.gov (United States)

    Dodge, H H; Mattek, N C; Austin, D; Hayes, T L; Kaye, J A

    2012-06-12

    To determine whether unobtrusive long-term in-home assessment of walking speed and its variability can distinguish those with mild cognitive impairment (MCI) from those with intact cognition. Walking speed was assessed using passive infrared sensors fixed in series on the ceiling of the homes of elderly individuals participating in the Intelligent Systems for Assessing Aging Change (ISAAC) cohort study. Latent trajectory models were used to analyze weekly mean speed and walking speed variability (coefficient of variation [COV]). ISAAC participants living alone included 54 participants with intact cognition, 31 participants with nonamnestic MCI (naMCI), and 8 participants with amnestic MCI at baseline, with a mean follow-up of 2.6 ± 1.0 years. Trajectory models identified 3 distinct trajectories (fast, moderate, and slow) of mean weekly walking speed. Participants with naMCI were more likely to be in the slow speed group than in the fast (p = 0.01) or moderate (p = 0.04) speed groups. For COV, 4 distinct trajectories were identified: group 1, the highest baseline and increasing COV followed by a sharply declining COV; groups 2 and 3, relatively stable COV; and group 4, the lowest baseline and decreasing COV. Participants with naMCI were more likely to be members of either highest or lowest baseline COV groups (groups 1 or 4), possibly representing the trajectory of walking speed variability for early- and late-stage MCI, respectively. Walking speed and its daily variability may be an early marker of the development of MCI. These and other real-time measures of function may offer novel ways of detecting transition phases leading to dementia.

  16. Walking in postpoliomyelitis syndrome: The relationships between time-scored tests, walking in daily life and perceived mobility problems

    NARCIS (Netherlands)

    H.L.D. Horemans (Herwin); J.B.J. Bussmann (Hans); A. Beelen (Anita); H.J. Stam (Henk); F. Nollet (Frans)

    2005-01-01

    textabstractObjective: To compare walking test results with walking in daily life, and to investigate the relationships between walking tests, walking activity in daily life, and perceived mobility problems in patients with post-poliomyelitis syndrome. Subjects: Twenty-four ambulant patients with po

  17. Head stabilization in children of both genders during level walking.

    Science.gov (United States)

    Mazzà, Claudia; Zok, Mounir; Cappozzo, Aurelio

    2010-04-01

    Young healthy adults adopt a "head stabilization in space" strategy during walking by attenuating the acceleration going up from pelvis-to-head level. A gender difference exists in this control strategy, particularly evident in the control of medio-lateral dynamic equilibrium. This study aims at assessing whether this difference is already present at pre-pubertal age. Two groups of children (15 females and 15 males, age range: 8-11 years) were involved in the study. They were asked to walk at self-selected speed and movement data were collected using three inertial sensors firmly attached at pelvis (P), shoulder (S), and head (H) levels. The RMS of the accelerations of P, S, and H were computed along the antero-posterior (AP), medio-lateral (ML), and vertical (V) directions and used to compare the two groups. No differences were found between the two groups in the pelvis and shoulder acceleration RMS values. Conversely, lower head acceleration RMS values were found for the females in both the AP and ML directions. Both groups managed to attenuate the upper body AP and ML accelerations going from pelvis-to-head level, with higher attenuations found for the females. The results of this study suggest that the gender differences in the ability to control the head accelerations during gait, found in a previous study, are due neither to different mass distribution nor to a compensation of the greater pelvic motions, nor are they the result of gender related walking habits (e.g. use of high heels).

  18. WALK Community Grants Scheme: lessons learned in developing and administering a health promotion microgrants program.

    Science.gov (United States)

    Caperchione, Cristina; Mummery, W Kerry; Joyner, Kelly

    2010-09-01

    The Women's Active Living Kits (WALK) Community Grant Scheme was a key component of a federally funded Australian initiative aimed at increasing local capacity to promote and engage priority women's groups in health-related physical activity. Under the program, community groups and organizations were provided with the opportunity to apply and receive small grants to support the development of women's walking groups with the aim of increasing physical activity participation levels in women, supporting innovative community ideas for increasing women's physical activity by improving social structures and environments, or both. This article describes the development and administration of the WALK Community Grant Scheme, outlines challenges and barriers encountered throughout the grant program process, and provides practical insights for replicating this initiative.

  19. Interval-walking training for the treatment of type 2 diabetes: a randomized, controlled trial

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Winding, Kamilla; Knudsen, Sine H.

    .05) and maximum (Ptraining is feasible in type 2 diabetes patients. CWT offsets the deterioration in glycemia seen in the control group, and IWT is superior to energy......Formål: To evaluate the feasibility of free-living walking training in type 2 diabetes patients, and to investigate the effects of interval-walking training (IWT) versus continuous-walking training (CWT) upon self reported health, physical fitness, body composition and glycemic control. Metoder......: Subjects with type 2 diabetes were randomized to a control (n = 8), CWT (n = 12), or IWT group (n = 12). Training groups were prescribed five sessions per week (60 min/session) and were controlled with an accelerometer and a heart-rate monitor. CWT performed all training at moderate intensity, whereas IWT...

  20. Angular momentum in human walking.

    Science.gov (United States)

    Herr, Hugh; Popovic, Marko

    2008-02-01

    Angular momentum is a conserved physical quantity for isolated systems where no external moments act about a body's center of mass (CM). However, in the case of legged locomotion, where the body interacts with the environment (ground reaction forces), there is no a priori reason for this relationship to hold. A key hypothesis in this paper is that angular momentum is highly regulated throughout the walking cycle about all three spatial directions [|Lt| approximately 0], and therefore horizontal ground reaction forces and the center of pressure trajectory can be explained predominantly through an analysis that assumes zero net moment about the body's CM. Using a 16-segment human model and gait data for 10 study participants, we found that calculated zero-moment forces closely match experimental values (Rx2=0.91; Ry2=0.90). Additionally, the centroidal moment pivot (point where a line parallel to the ground reaction force, passing through the CM, intersects the ground) never leaves the ground support base, highlighting how closely the body regulates angular momentum. Principal component analysis was used to examine segmental contributions to whole-body angular momentum. We found that whole-body angular momentum is small, despite substantial segmental momenta, indicating large segment-to-segment cancellations ( approximately 95% medio-lateral, approximately 70% anterior-posterior and approximately 80% vertical). Specifically, we show that adjacent leg-segment momenta are balanced in the medio-lateral direction (left foot momentum cancels right foot momentum, etc.). Further, pelvis and abdomen momenta are balanced by leg, chest and head momenta in the anterior-posterior direction, and leg momentum is balanced by upper-body momentum in the vertical direction. Finally, we discuss the determinants of gait in the context of these segment-to-segment cancellations of angular momentum.

  1. Body weight supported treadmill training versus traditional training in patients dependent on walking assistance after stroke: a randomized controlled trial.

    Science.gov (United States)

    Høyer, Ellen; Jahnsen, Reidun; Stanghelle, Johan Kvalvik; Strand, Liv Inger

    2012-01-01

    Treadmill training with body weight support (TTBWS) for relearning walking ability after brain damage is an approach under current investigation. Efficiency of this method beyond traditional training is lacking evidence, especially in patients needing walking assistance after stroke. The objective of this study was to investigate change in walking and transfer abilities, comparing TTBWS with traditional walking training. A single-blinded, randomized controlled trial was conducted. Sixty patients referred for multi-disciplinary primary rehabilitation were assigned into one of two intervention groups, one received 30 sessions of TTBWS plus traditional training, the other traditional training alone. Daily training was 1 hr. Outcome measures were Functional Ambulation Categories (FAC), Walking, Functional Independence Measure (FIM); shorter transfer and stairs, 10 m and 6-min walk tests. Substantial improvements in walking and transfer were shown within both groups after 5 and 11 weeks of intervention. Overall no statistical significant differences were found between the groups, but 12 of 17 physical measures tended to show improvements in favour of the treadmill approach. Both training strategies provided significant improvements in the tested activities, suggesting that similar outcomes can be obtained in the two modalities by systematic, intensive and goal directed training.

  2. The effects of a motor and a cognitive concurrent task on walking in children with developmental coordination disorder.

    Science.gov (United States)

    Cherng, Rong-Ju; Liang, Ling-Yin; Chen, Yung-Jung; Chen, Jenn-Yeu

    2009-02-01

    The effects of type (cognitive vs. motor) and difficulty level (easy vs. hard) of a concurrent task on walking were examined in 10 boys and 4 girls (age 4-6 years) with developmental coordination disorder (DCD) and 28 age- and gender-matched unaffected children. Each child performed free walking (single task), walking while carrying an empty tray (dual task, the concurrent task being motor and easy), walking while carrying a tray with 7 marbles (the concurrent task being motor and hard), walking while repeating a series of digits forward (the concurrent task being cognitive and easy), and walking while repeating the digits backward (the concurrent task being cognitive and hard). Walking was affected by the concurrent task (i.e., dual-task cost) in the children with DCD more so than in the comparison children. Greater task difficulty also increased the dual-task cost in the children with DCD more so than in the comparison children. These patterns were only noted for the motor concurrent task. The cognitive concurrent task also affected walking, but the dual-task costs did not differ between difficulty levels, nor between the groups.

  3. Synchronous EMG activity in the piper frequency band reveals the corticospinal demand of walking tasks.

    Science.gov (United States)

    Clark, David J; Kautz, Steven A; Bauer, Andrew R; Chen, Yen-Ting; Christou, Evangelos A

    2013-08-01

    Evidence indicates that the frequency-domain characteristics of surface electromyogram (EMG) signals are modulated according to the contributing sources of neural drive. Modulation of inter-muscular EMG synchrony within the Piper frequency band (30-60 Hz) during movement tasks has been linked to drive from the corticospinal tract. However, it is not known whether EMG synchrony is sufficiently sensitive to detect task-dependent differences in the corticospinal contribution to leg muscle activation during walking. We investigated this question in seventeen healthy older men and women. It was hypothesized that, relative to typical steady state walking, Piper band EMG synchrony of the triceps surae muscle group would be reduced for dual-task walking (because of competition for cortical resources), similar for fast walking (because walking speed is directed by an indirect locomotor pathway rather than by the corticospinal tract), and increased when taking a long step (because voluntary gait pattern modifications are directed by the corticospinal tract). Each of these hypotheses was confirmed. These findings support the use of frequency-domain analysis of EMG in future investigations into the corticospinal contribution to control of healthy and disordered human walking.

  4. Synchronous EMG activity in the Piper frequency band reveals the corticospinal demand of walking tasks

    Science.gov (United States)

    Clark, David J.; Kautz, Steven A.; Bauer, Andrew R.; Chen, Yen-Ting; Christou, Evangelos A.

    2013-01-01

    Evidence indicates that the frequency-domain characteristics of surface electromyogram (EMG) signals are modulated according to the contributing sources of neural drive. Modulation of inter-muscular EMG synchrony within the Piper frequency band (30–60Hz) during movement tasks has been linked to drive from the corticospinal tract. However, it is not known whether EMG synchrony is sufficiently sensitive to detect task-dependent differences in the corticospinal contribution to leg muscle activation during walking. We investigated this question in seventeen healthy older men and women. It was hypothesized that, relative to typical steady state walking, Piper band EMG synchrony of the triceps surae muscle group would be reduced for dual-task walking (because of competition for cortical resources), similar for fast walking (because walking speed is directed by an intermediate locomotor pathway rather than by the corticospinal tract), and increased when taking a long step (because voluntary gait pattern modifications are directed by the corticospinal tract). Each of these hypotheses was confirmed. These findings support the use of frequency-domain analysis of EMG in future investigations into the corticospinal contribution to control of healthy and disordered human walking. PMID:23740367

  5. A Simple Exoskeleton That Assists Plantarflexion Can Reduce the Metabolic Cost of Human Walking

    Science.gov (United States)

    Malcolm, Philippe; Derave, Wim; Galle, Samuel; De Clercq, Dirk

    2013-01-01

    Background Even though walking can be sustained for great distances, considerable energy is required for plantarflexion around the instant of opposite leg heel contact. Different groups attempted to reduce metabolic cost with exoskeletons but none could achieve a reduction beyond the level of walking without exoskeleton, possibly because there is no consensus on the optimal actuation timing. The main research question of our study was whether it is possible to obtain a higher reduction in metabolic cost by tuning the actuation timing. Methodology/Principal Findings We measured metabolic cost by means of respiratory gas analysis. Test subjects walked with a simple pneumatic exoskeleton that assists plantarflexion with different actuation timings. We found that the exoskeleton can reduce metabolic cost by 0.18±0.06 W kg−1 or 6±2% (standard error of the mean) (p = 0.019) below the cost of walking without exoskeleton if actuation starts just before opposite leg heel contact. Conclusions/Significance The optimum timing that we found concurs with the prediction from a mathematical model of walking. While the present exoskeleton was not ambulant, measurements of joint kinetics reveal that the required power could be recycled from knee extension deceleration work that occurs naturally during walking. This demonstrates that it is theoretically possible to build future ambulant exoskeletons that reduce metabolic cost, without power supply restrictions. PMID:23418524

  6. A simple exoskeleton that assists plantarflexion can reduce the metabolic cost of human walking.

    Directory of Open Access Journals (Sweden)

    Philippe Malcolm

    Full Text Available BACKGROUND: Even though walking can be sustained for great distances, considerable energy is required for plantarflexion around the instant of opposite leg heel contact. Different groups attempted to reduce metabolic cost with exoskeletons but none could achieve a reduction beyond the level of walking without exoskeleton, possibly because there is no consensus on the optimal actuation timing. The main research question of our study was whether it is possible to obtain a higher reduction in metabolic cost by tuning the actuation timing. METHODOLOGY/PRINCIPAL FINDINGS: We measured metabolic cost by means of respiratory gas analysis. Test subjects walked with a simple pneumatic exoskeleton that assists plantarflexion with different actuation timings. We found that the exoskeleton can reduce metabolic cost by 0.18±0.06 W kg(-1 or 6±2% (standard error of the mean (p = 0.019 below the cost of walking without exoskeleton if actuation starts just before opposite leg heel contact. CONCLUSIONS/SIGNIFICANCE: The optimum timing that we found concurs with the prediction from a mathematical model of walking. While the present exoskeleton was not ambulant, measurements of joint kinetics reveal that the required power could be recycled from knee extension deceleration work that occurs naturally during walking. This demonstrates that it is theoretically possible to build future ambulant exoskeletons that reduce metabolic cost, without power supply restrictions.

  7. Strategy adoption and locomotor adjustment in obstacle clearance of newly walking toddlers with Down syndrome after different treadmill interventions.

    Science.gov (United States)

    Wu, Jianhua; Ulrich, Dale A; Looper, Julia; Tiernan, Chad W; Angulo-Barroso, Rosa M

    2008-03-01

    This study investigated how newly walking toddlers with Down syndrome (DS), after different treadmill interventions, adopted clearance strategies and modified anticipatory locomotor adjustment patterns to negotiate an obstacle in their travel path. Thirty infants with DS (about 10 months of age) were recruited and randomly assigned to either a lower-intensity, generalized (LG) treadmill training group, or a higher-intensity, individualized (HI) treadmill training group. Thirteen in each group completed a one-year-gait follow-up after the treadmill intervention. Initially, both groups chose to either crawl or walk over an obstacle. However, walking over the obstacle became their preferred clearance strategy over the course of the gait follow-up even though the height of the obstacle increased from visit to visit. The HI group used the strategy of walking over the obstacle at a considerably higher percentage than the LG group within 6 months after the training. When approaching the obstacle, both groups started to show consistent anticipatory locomotor adjustments about 6 months after the training. Both groups decreased velocity, cadence and step length, and increased step width at the last three pre-obstacle steps. It was concluded that the retention of the HI training effects led the HI group to predominantly walk over an obstacle earlier than the LG group within 6 months after treadmill intervention, and the two groups produced similar anticipatory locomotor adjustments in the last three steps before negotiating the obstacle.

  8. Accelerometric assessment of different dimensions of natural walking during the first year after stroke : Recovery of amount, distribution, quality and speed of walking

    NARCIS (Netherlands)

    M.C. Sánchez (Marina Castel); J.B.J. Bussmann (Hans); W.G.M. Janssen (Wim); H.L.D. Horemans (Herwin); S. Chastin (Sebastian); M. Heijenbrok (Majanka); H.J. Stam (Henk)

    2015-01-01

    textabstractObjectives: To describe the course of walking behaviour over a period of 1 year after stroke, using accelerometry, and to compare 1-year data with those from a healthy group. Design: One-year follow-up cohort study. Subjects: Twenty-three stroke patients and 20 age-matched healthy subjec

  9. Can the Cardiopulmonary 6-Minute Walk Test Reproduce the Usual Activities of Patients with Heart Failure?

    Directory of Open Access Journals (Sweden)

    Guimarães Guilherme Veiga

    2002-01-01

    Full Text Available OBJECTIVE: The 6-minute walk test is an way of assessing exercise capacity and predicting survival in heart failure. The 6-minute walk test was suggested to be similar to that of daily activities. We investigated the effect of motivation during the 6-minute walk test in heart failure. METHODS: We studied 12 males, age 45±12 years, ejection fraction 23±7%, and functional class III. Patients underwent the following tests: maximal cardiopulmonary exercise test on the treadmill (max, cardiopulmonary 6-minute walk test with the walking rhythm maintained between relatively easy and slightly tiring (levels 11 and 13 on the Borg scale (6EB, and cardiopulmonary 6-minute walk test using the usual recommendations (6RU. The 6EB and 6RU tests were performed on a treadmill with zero inclination and control of the velocity by the patient. RESULTS: The values obtained in the max, 6EB, and 6RU tests were, respectively, as follows: O2 consumption (ml.kg-1.min-1 15.4±1.8, 9.8±1.9 (60±10%, and 13.3±2.2 (90±10%; heart rate (bpm 142±12, 110±13 (77±9%, and 126±11 (89±7%; distance walked (m 733±147, 332±66, and 470±48; and respiratory exchange ratio (R 1.13±0.06, 0.9±0.06, and 1.06±0.12. Significant differences were observed in the values of the variables cited between the max and 6EB tests, the max and 6RU tests, and the 6EB and 6RU tests (p<0.05. CONCLUSION: Patients, who undergo the cardiopulmonary 6-minute walk test and are motivated to walk as much as they possibly can, usually walk almost to their maximum capacity, which may not correspond to that of their daily activities. The use of the Borg scale during the cardiopulmonary 6-minute walk test seems to better correspond to the metabolic demand of the usual activities in this group of patients.

  10. Dynamic stability during level walking and obstacle crossing in persons with facioscapulohumeral muscular dystrophy.

    Science.gov (United States)

    Rijken, N H M; van Engelen, B G M; Geurts, A C H; Weerdesteyn, V

    2015-09-01

    Patients with FSHD suffer from progressive skeletal muscle weakness, which is associated with an elevated fall risk. To obtain insight into fall mechanisms in this patient group, we aimed to assess dynamic stability during level walking and obstacle crossing in patients at different disease stages. Ten patients with at least some lower extremity weakness were included, of whom six were classified as moderately affected and four as mildly affected. Ten healthy controls were also included. Level walking at comfortable speed was assessed, as well as crossing a 10 cm high wooden obstacle. We assessed forward and lateral dynamic stability, as well as spatiotemporal and kinematics variables. During level walking, the moderately affected group demonstrated a lower walking speed, which was accompanied by longer step times and smaller step lengths, yet dynamic stability was unaffected. When crossing the obstacle, however, the moderately affected patients demonstrated reduced forward stability margins during the trailing step, which was accompanied by an increased toe clearance and greater trunk and hip flexion. This suggests that during level walking, the patients effectively utilized compensatory strategies for maintaining dynamic stability, but that the moderately affected group lacked the capacity to fully compensate for the greater stability demands imposed by obstacle crossing, rendering them unable to maintain optimal stability levels. The present results highlight the difficulties that FSHD patients experience in performing this common activity of daily living and may help explain their propensity to fall in the forward direction.

  11. Toe clearance and velocity profiles of young and elderly during walking on sloped surfaces

    Directory of Open Access Journals (Sweden)

    Begg Rezaul K

    2010-04-01

    Full Text Available Abstract Background Most falls in older adults are reported during locomotion and tripping has been identified as a major cause of falls. Challenging environments (e.g., walking on slopes are potential interventions for maintaining balance and gait skills. The aims of this study were: 1 to investigate whether or not distributions of two important gait variables [minimum toe clearance (MTC and foot velocity at MTC (VelMTC] and locomotor control strategies are altered during walking on sloped surfaces, and 2 if altered, are they maintained at two groups (young and elderly female groups. Methods MTC and VelMTC data during walking on a treadmill at sloped surfaces (+3°, 0° and -3° were analysed for 9 young (Y and 8 elderly (E female subjects. Results MTC distributions were found to be positively skewed whereas VelMTC distributions were negatively skewed for both groups on all slopes. Median MTC values increased (Y = 33%, E = 7% at negative slope but decreased (Y = 25%, E = 15% while walking on the positive slope surface compared to their MTC values at the flat surface (0°. Analysis of VelMTC distributions also indicated significantly (p th percentile (Q1 values in the elderly at all slopes. Conclusion The young displayed a strong positive correlation between MTC median changes and IQR (interquartile range changes due to walking on both slopes; however, such correlation was weak in the older adults suggesting differences in control strategies being employed to minimize the risk of tripping.

  12. Assessing walking behaviors of selected subpopulations.

    Science.gov (United States)

    Le Masurier, Guy C; Bauman, Adrian E; Corbin, Charles B; Konopack, James F; Umstattd, Renee M; VAN Emmerik, Richard E A

    2008-07-01

    Recent innovations in physical activity (PA) assessment have made it possible to assess the walking behaviors of a wide variety of populations. Objective measurement methods (e.g., pedometers, accelerometers) have been widely used to assess walking and other prevalent types of PA. Questionnaires suitable for international populations (e.g., the International Physical Activity Questionnaire and the Global Physical Activity Questionnaire) and measurement techniques for the assessment of gait patterns in disabled populations allow for the study of walking and its health benefits among many populations. Results of studies using the aforementioned techniques indicate that children are more active than adolescents and adolescents are more active than adults. Males, particularly young males, are typically more active than females. The benefits associated with regular participation in PA for youth and walking for older adults have been well documented, although improvements in the assessments of physical, cognitive, and psychosocial parameters must be made if we are to fully understand the benefits of walking for people of all ages. Most youth meet appropriate age-related PA activity recommendations, but adults, particularly older adults and adults with disabilities, are less likely to meet PA levels necessary for the accrual of health benefits. International studies indicate variation in walking by culture. It is clear, however, that walking is a prevalent form of PA across countries and a movement form that has great potential in global PA promotion. Continued development of measurement techniques that allow for the study of individualized gait patterns will help us add to the already rich body of knowledge on chronically disabled populations and allow for individual prescriptions for these populations.

  13. Kinematic evaluation of virtual walking trajectories.

    Science.gov (United States)

    Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

    2013-04-01

    Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

  14. Energy efficient walking with central pattern generators: from passive dynamic walking to biologically inspired control

    NARCIS (Netherlands)

    Verdaasdonk, B.W.; Koopman, H.F.J.M.; Van der Helm, F.C.T.

    2009-01-01

    Like human walking, passive dynamic walking—i.e. walking down a slope with no actuation except gravity—is energy efficient by exploiting the natural dynamics. In the animal world, neural oscillators termed central pattern generators (CPGs) provide the basic rhythm for muscular activity in

  15. Does walking strategy in older people change as a function of walking distance?

    NARCIS (Netherlands)

    Najafi, Bijan; Helbostad, Jorunn L.; Moe-Nilssen, Rolf; Zijlstra, Wiebren; Aminian, Kamiar

    2009-01-01

    This study investigates whether the spatio-temporal parameters of gait in the elderly vary as a function of walking distance. The gait pattern of older subjects (n = 27) over both short (SWD <10 m) and long (LWD > 20 in) walking was evaluated using an ambulatory device consisting of body-worn sensor

  16. The associated random walk and martingales in random walks with stationary increments

    CERN Document Server

    Grey, D R

    2010-01-01

    We extend the notion of the associated random walk and the Wald martingale in random walks where the increments are independent and identically distributed to the more general case of stationary ergodic increments. Examples are given where the increments are Markovian or Gaussian, and an application in queueing is considered.

  17. The effect of walking aids on muscle activation patterns during walking in stroke patients

    NARCIS (Netherlands)

    Buurke, Jaap; Hermens, Hermanus J.; Erren-Wolters, C.V.; Nene, A.V.

    2005-01-01

    The purpose of this study was to investigate changes in muscle activation patterns with respect to timing and amplitude that occur when subjects with stroke walk with and without a walking aid. This knowledge could help therapists in deciding whether or not patients should use a cane or quad stick w

  18. Walking and child pedestrian injury: a systematic review of built environment correlates of safe walking.

    Science.gov (United States)

    Rothman, Linda; Buliung, Ron; Macarthur, Colin; To, Teresa; Howard, Andrew

    2014-02-01

    The child active transportation literature has focused on walking, with little attention to risk associated with increased traffic exposure. This paper reviews the literature related to built environment correlates of walking and pedestrian injury in children together, to broaden the current conceptualization of walkability to include injury prevention. Two independent searches were conducted focused on walking in children and child pedestrian injury within nine electronic databases until March, 2012. Studies were included which: 1) were quantitative 2) set in motorized countries 3) were either urban or suburban 4) investigated specific built environment risk factors 5) had outcomes of either walking in children and/or child pedestrian roadway collisions (ages 0-12). Built environment features were categorized according to those related to density, land use diversity or roadway design. Results were cross-tabulated to identify how built environment features associate with walking and injury. Fifty walking and 35 child pedestrian injury studies were identified. Only traffic calming and presence of playgrounds/recreation areas were consistently associated with more walking and less pedestrian injury. Several built environment features were associated with more walking, but with increased injury. Many features had inconsistent results or had not been investigated for either outcome. The findings emphasise the importance of incorporating safety into the conversation about creating more walkable cities.

  19. Energy efficient walking with central pattern generators: from passive dynamic walking to biologically inspired control

    NARCIS (Netherlands)

    Verdaasdonk, B.W.; Koopman, H.F.J.M.; Van der Helm, F.C.T.

    2009-01-01

    Like human walking, passive dynamic walking—i.e. walking down a slope with no actuation except gravity—is energy efficient by exploiting the natural dynamics. In the animal world, neural oscillators termed central pattern generators (CPGs) provide the basic rhythm for muscular activity in locomotion

  20. Sensor-driven four-channel stimulation of paretic leg: functional electrical walking therapy.

    Science.gov (United States)

    Kojović, Jovana; Djurić-Jovicić, Milica; Dosen, Strahinja; Popović, Mirjana B; Popović, Dejan B

    2009-06-30

    This study introduces a Functional Electrical Therapy (FET) system based on sensor-driven electrical stimulation for the augmentation of walking. The automatic control relates to the timing of stimulation of four muscles. The sensor system comprises accelerometers and force-sensing resistors. The automatic control implements IF-THEN rules designed by mapping of sensors and muscle activation patterns. The new system was tested in 13 acute stroke patients assigned to a FET group or a control (CON) group. Both groups were treated with a standard rehabilitation program and 45min of walking daily for 5 days over the course of 4 weeks. The FET group received electrical stimulation during walking. The Fugl-Meyer (FM) test for the lower extremities, Barthel Index (BI), mean walking velocity (v(mean)) over a 6-m distance, and Physiological Cost Index (PCI) were assessed at the entry point and at the end of the treatment. Subjects within the FET and CON groups had comparable baseline outcome measures. In the FET group, we determined significant differences in the mean values of all outcomes between the entry and end points of treatment (p0.05). We also found significant differences in the changes of FM, BI, v(mean) and PCI which occurred during the 4 weeks of treatment between the FET and CON groups (p<0.05). The statistical strength of the clinical study was low (<70%), suggesting the need for a larger, randomized clinical trial.

  1. Walking economy during cued versus non-cued self-selected treadmill walking in persons with Parkinson's disease.

    Science.gov (United States)

    Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

    2014-01-01

    Gait impairments related to Parkinson's disease (PD) include variable step length and decreased walking velocity, which may result in poorer walking economy. Auditory cueing is a common method used to improve gait mechanics in PD that has been shown to worsen walking economy at set treadmill walking speeds. It is unknown if auditory cueing has the same effects on walking economy at self-selected treadmill walking speeds. To determine if auditory cueing will affect walking economy at self-selected treadmill walking speeds and at speeds slightly faster and slower than self-selected. Twenty-two participants with moderate PD performed three, 6-minute bouts of treadmill walking at three speeds (self-selected and ± 0.22 m·sec-1). One session used cueing and the other without cueing. Energy expenditure was measured and walking economy was calculated (energy expenditure/power). Poorer walking economy and higher energy expenditure occurred during cued walking at a self-selected and a slightly faster walking speed, but there was no apparent difference at the slightly slower speed. These results suggest that potential gait benefits of auditory cueing may come at an energy cost and poorer walking economy for persons with PD at least at some treadmill walking speeds.

  2. Evaluation of the walking pattern in clubfoot patients who received early intensive treatment

    DEFF Research Database (Denmark)

    Alkjaer, T; Pedersen, E N; Simonsen, E B

    2000-01-01

    joint in the clubfeet could possibly be owing to weaker plantar flexors. In conclusion, gait analysis can be an important tool when evaluating treatment for clubfoot. However, further investigation is needed to determine whether the higher hip and knee joint moments observed in subjects with clubfoot......The walking pattern in a group of nine adult male subjects who had received early intensive treatment for congenital clubfoot was evaluated and compared to the walking pattern in a control group of 15 adult healthy male subjects. All subjects were filmed with a five-camera video system...

  3. How to analyse a Big Bang of data: the mammoth project at the Cern physics laboratory in Geneva to recreate the conditions immediately after the universe began requires computing power on an unprecedented scale

    CERN Multimedia

    Thomas, Kim

    2005-01-01

    How to analyse a Big Bang of data: the mammoth project at the Cern physics laboratory in Geneva to recreate the conditions immediately after the universe began requires computing power on an unprecedented scale

  4. Psychometric performance of a generic walking scale (Walk-12G) in multiple sclerosis and Parkinson's disease.

    Science.gov (United States)

    Bladh, Stina; Nilsson, Maria H; Hariz, Gun-Marie; Westergren, Albert; Hobart, Jeremy; Hagell, Peter

    2012-04-01

    Walking difficulties are common in neurological and other disorders, as well as among the elderly. There is a need for reliable and valid instruments for measuring walking difficulties in everyday life since existing gait tests are clinician rated and focus on situation specific capacity. The Walk-12G was adapted from the 12-item multiple sclerosis walking scale as a generic patient-reported rating scale for walking difficulties in everyday life. The aim of this study is to examine the psychometric properties of the Walk-12G in people with multiple sclerosis (MS) and Parkinson's disease (PD). The Walk-12G was translated into Swedish and evaluated qualitatively among 25 people with and without various neurological and other conditions. Postal survey (MS, n = 199; PD, n = 189) and clinical (PD, n = 36) data were used to test its psychometric properties. Respondents considered the Walk-12G relevant and easy to use. Mean completion time was 3.5 min. Data completeness was good (0.6). Coefficient alpha and test-retest reliabilities were >0.9, and standard errors of measurement were 2.3-2.8. Construct validity was supported by correlations in accordance with a priori expectations. Results are similar to those with previous Walk-12G versions, indicating that scale adaptation was successful. Data suggest that the Walk-12G meets rating scale criteria for clinical trials, making it a valuable complement to available gait tests. Further studies involving other samples and application of modern psychometric methods are warranted to examine the scale in more detail.

  5. Early application of tail nerve electrical stimulation-induced walking training promotes locomotor recovery in rats with spinal cord injury.

    Science.gov (United States)

    Zhang, S-X; Huang, F; Gates, M; Shen, X; Holmberg, E G

    2016-11-01

    This is a randomized controlled prospective trial with two parallel groups. The objective of this study was to determine whether early application of tail nerve electrical stimulation (TANES)-induced walking training can improve the locomotor function. This study was conducted in SCS Research Center in Colorado, USA. A contusion injury to spinal cord T10 was produced using the New York University impactor device with a 25 -mm height setting in female, adult Long-Evans rats. Injured rats were randomly divided into two groups (n=12 per group). One group was subjected to TANES-induced walking training 2 weeks post injury, and the other group, as control, received no TANES-induced walking training. Restorations of behavior and conduction were assessed using the Basso, Beattie and Bresnahan open-field rating scale, horizontal ladder rung walking test and electrophysiological test (Hoffmann reflex). Early application of TANES-induced walking training significantly improved the recovery of locomotor function and benefited the restoration of Hoffmann reflex. TANES-induced walking training is a useful method to promote locomotor recovery in rats with spinal cord injury.

  6. Torque-stiffness-controlled dynamic walking with central pattern generators.

    Science.gov (United States)

    Huang, Yan; Vanderborght, Bram; Van Ham, Ronald; Wang, Qining

    2014-12-01

    Walking behavior is modulated by controlling joint torques in most existing passivity-based bipeds. Controlled Passive Walking with adaptable stiffness exhibits controllable natural motions and energy efficient gaits. In this paper, we propose torque-stiffness-controlled dynamic bipedal walking, which extends the concept of Controlled Passive Walking by introducing structured control parameters and a bio-inspired control method with central pattern generators. The proposed walking paradigm is beneficial in clarifying the respective effects of the external actuation and the internal natural dynamics. We present a seven-link biped model to validate the presented walking. Effects of joint torque and joint stiffness on gait selection, walking performance and walking pattern transitions are studied in simulations. The work in this paper develops a new solution of motion control of bipedal robots with adaptable stiffness and provides insights of efficient and sophisticated walking gaits of humans.

  7. Vection in depth during treadmill walking.

    Science.gov (United States)

    Ash, April; Palmisano, Stephen; Apthorp, Deborah; Allison, Robert S

    2013-01-01

    Vection has typically been induced in stationary observers (ie conditions providing visual-only information about self-motion). Two recent studies have examined vection during active treadmill walking--one reported that treadmill walking in the same direction as the visually simulated self-motion impaired vection (Onimaru et al, 2010 Journal of Vision 10(7):860), the other reported that it enhanced vection (Seno et al, 2011 Perception 40 747-750; Seno et al, 2011 Attention, Perception, & Psychophysics 73 1467-1476). Our study expands on these earlier investigations of vection during observer active movement. In experiment 1 we presented radially expanding optic flow and compared the vection produced in stationary observers with that produced during walking forward on a treadmill at a 'matched' speed. Experiment 2 compared the vection induced by forward treadmill walking while viewing expanding or contracting optic flow with that induced by viewing playbacks of these same displays while stationary. In both experiments subjects' tracked head movements were either incorporated into the self-motion displays (as simulated viewpoint jitter) or simply ignored. We found that treadmill walking always reduced vection (compared with stationary viewing conditions) and that simulated viewpoint jitter always increased vection (compared with constant velocity displays). These findings suggest that while consistent visual-vestibular information about self-acceleration increases vection, biomechanical self-motion information reduces this experience (irrespective of whether it is consistent or not with the visual input).

  8. Scaling Argument of Anisotropic Random Walk

    Institute of Scientific and Technical Information of China (English)

    XU Bing-Zhen; JIN Guo-Jun; WANG Fei-Feng

    2005-01-01

    In this paper, we analytically discuss the scaling properties of the average square end-to-end distance for anisotropic random walk in D-dimensional space ( D ≥ 2), and the returning probability Pn(ro) for the walker into a certain neighborhood of the origin. We will not only give the calculating formula for and Pn (ro), but also point out that if there is a symmetric axis for the distribution of the probability density of a single step displacement, we always obtain ~ n, where ⊥ refers to the projections of the displacement perpendicular to each symmetric axes of the walk; in D-dimensional space with D symmetric axes perpendicular to each other, we always have ~ n and the random walk will be like a purely random motion; if the number of inter-perpendicular symmetric axis is smaller than the dimensions of the space, we must have ~ n2 for very large n and the walk will be like a ballistic motion. It is worth while to point out that unlike the isotropic random walk in one and two dimensions, which is certain to return into the neighborhood of the origin, generally there is only a nonzero probability for the anisotropic random walker in two dimensions to return to the neighborhood.

  9. Coined quantum walks on percolation graphs

    CERN Document Server

    Leung, Godfrey; Bailey, Joe; Kendon, Viv

    2010-01-01

    Quantum walks, both discrete (coined) and continuous time, form the basis of several quantum algorithms and have been used to model processes such as transport in spin chains and quantum chemistry. The enhanced spreading and mixing properties of quantum walks compared with their classical counterparts have been well-studied on regular structures and also shown to be sensitive to defects and imperfections in the lattice. As a simple example of a disordered system, we consider percolation lattices, in which edges or sites are randomly missing, interrupting the progress of the quantum walk. We use numerical simulation to study the properties of coined quantum walks on these percolation lattices in one and two dimensions. In one dimension (the line) we introduce a simple notion of quantum tunneling and determine how this affects the properties of the quantum walk as it spreads. On two-dimensional percolation lattices, we show how the spreading rate varies from linear to square root in the number of steps, as the ...

  10. Effects of obesity on lower extremity muscle function during walking at two speeds.

    Science.gov (United States)

    Lerner, Zachary F; Board, Wayne J; Browning, Raymond C

    2014-03-01

    Walking is a recommended form of physical activity for obese adults, yet the effects of obesity and walking speed on the biomechanics of walking are not well understood. The purpose of this study was to examine joint kinematics, muscle force requirements and individual muscle contributions to the walking ground reaction forces (GRFs) at two speeds (1.25 ms(-1) and 1.50 ms(-1)) in obese and nonobese adults. Vasti (VAS), gluteus medius (GMED), gastrocnemius (GAST), and soleus (SOL) forces and their contributions to the GRFs were estimated using three-dimensional musculoskeletal models scaled to the anthropometrics of nine obese (35.0 (3.78 kg m(-2))); body mass index mean (SD)) and 10 nonobese (22.1 (1.02 kg m(-2))) subjects. The obese individuals walked with a straighter knee in early stance at the faster speed and greater pelvic obliquity during single limb support at both speeds. Absolute force requirements were generally greater in obese vs. nonobese adults, the main exception being VAS, which was similar between groups. At both speeds, lean mass (LM) normalized force output for GMED was greater in the obese group. Obese individuals appear to adopt a gait pattern that reduces VAS force output, especially at speeds greater than their preferred walking velocity. Greater relative GMED force requirements in obese individuals may contribute to altered kinematics and increased risk of musculoskeletal injury/pathology. Our results suggest that obese individuals may have relative weakness of the VAS and hip abductor muscles, specifically GMED, which may act to increase their risk of musculoskeletal injury/pathology during walking, and therefore may benefit from targeted muscle strengthening. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Intersegmental coordination while walking up inclined surfaces: age and ramp angle effects.

    Science.gov (United States)

    Noble, Jeremy W; Prentice, Stephen D

    2008-08-01

    The lower-limb segment elevation angles during human locomotion have been shown to co-vary in a manner such that they approximate a plane when plotted against each other over a gait cycle. This relationship has been described as the Planar Co-Variation Law and has been shown to be consistent across various modes of locomotion on level ground. The goal of this study is to determine whether the Planar Co-Variation Law will hold in situations where the orientation of the walking surface is altered and if aging will have an effect on this intersegmental coordination during these locomotor tasks. Nine healthy young females (mean age = 21.4), and nine older adult females (mean age = 73.3) were asked to complete walking trials on level ground, and walking up ramps with inclines of 3 degrees , 6 degrees , 9 degrees and 12 degrees while the kinematics of their lower limbs were measured. It was found that the Planar Co-Variation Law was held across all ramp incline conditions by both the young adult and older adult groups. It was found that the changes in intersegmental coordination required to walk up the ramp resulted in a unique orientation of the co-variation plane for both groups when walking up a particular incline. The results of this study indicate that the Planar Co-Variation Law will include situations where the walking surface is not level and provides further support to models of motor control that have been proposed where walking patterns for different modes of gait can be predicted based on the orientation of the co-variation plane.

  12. Walking and health care expenditures among adult users of the Brazilian public healthcare system: retrospective cross-sectional study.

    Science.gov (United States)

    Turi, Bruna Camilo; Codogno, Jamile Sanches; Fernandes, Rômulo Araújo; Monteiro, Henrique Luiz

    2015-11-01

    Physical inactivity is a major public health challenge due to its association with chronic diseases and the resulting economic impact on the public healthcare system. However, walking can help alleviate these problems. Aim To verify associations between walking during leisure-time, risk factors and health care expenditure among users of the Brazilian public health care system. Methods The sample consisted of 963 adults. Walking was evaluated using the Baecke questionnaire. The total expenditure per year was evaluated through the demand for health care services, verified in the medical records of each participant. Results Walking was reported as a physical activity during leisure-time by 64.4% of the participants. The group with the highest engagement in walking was younger and presented lower values for BMI, WC and expenditure on medication. Participants inserted in the category of higher involvement in walking were 41% less likely to be inserted into the group with higher total expenditure (OR = 0:59; 95% CI 0.39-0.89). Conclusion It was found that walking was the most frequent leisure-time physical activity reported by users of the Brazilian health care system and was associated with lower total and medication expenditure.

  13. 30 min of treadmill walking at self-selected speed does not increase gait variability in independent elderly.

    Science.gov (United States)

    Da Rocha, Emmanuel S; Kunzler, Marcos R; Bobbert, Maarten F; Duysens, Jacques; Carpes, Felipe P

    2017-09-04

    Walking is one of the preferred exercises among elderly, but could a prolonged walking increase gait variability, a risk factor for a fall in the elderly? Here we determine whether 30 min of treadmill walking increases coefficient of variation of gait in elderly. Because gait responses to exercise depend on fitness level, we included 15 sedentary and 15 active elderly. Sedentary participants preferred a lower gait speed and made smaller steps than the actives. Step length coefficient of variation decreased ~16.9% by the end of the exercise in both the groups. Stride length coefficient of variation decreased ~9% after 10 minutes of walking, and sedentary elderly showed a slightly larger step width coefficient of variation (~2%) at 10 min than active elderly. Active elderly showed higher walk ratio (step length/cadence) than sedentary in all times of walking, but the times did not differ in both the groups. In conclusion, treadmill gait kinematics differ between sedentary and active elderly, but changes over time are similar in sedentary and active elderly. As a practical implication, 30 min of walking might be a good strategy of exercise for elderly, independently of the fitness level, because it did not increase variability in step and stride kinematics, which is considered a risk of fall in this population.

  14. Do you remember proposing marriage to the Pepsi machine? False recollections from a campus walk.

    Science.gov (United States)

    Seamon, John G; Philbin, Morgan M; Harrison, Liza G

    2006-10-01

    During a campus walk, participants were given familiar or bizarre action statements (e.g., "Check the Pepsi machine for change" vs. "Propose marriage to the Pepsi machine") with instructions either to perform the actions or imagine performing the actions (Group 1) or to watch the experimenter perform the actions or imagine the experimenter performing the actions (Group 2). One day later, some actions were repeated, along with new actions, on a second walk. Two weeks later, the participants took a recognition test for actions presented during the first walk, and they specified whether a recognized action was imagined or performed. Imagining themselves or the experimenter performing familiar or bizarre actions just once led to false recollections of performance for both types of actions. This study extends previous research on imagination inflation by demonstrating that these false performance recollections can occur in a natural, real-life setting following just one imagining.

  15. Fast Scramblers, Democratic Walks and Information Fields

    CERN Document Server

    Magan, Javier M

    2015-01-01

    We study a family of weighted random walks on complete graphs. These `democratic walks' turn out to be explicitly solvable, and we find the hierarchy window for which the characteristic time scale saturates the so-called fast scrambling conjecture. We show that these democratic walks describe well the properties of information spreading in systems in which every degree of freedom interacts with every other degree of freedom, such as Matrix or infinite range models. The argument is based on the analysis of suitably defined `Information fields' ($\\mathcal{I}$), which are shown to evolve stochastically towards stationarity due to unitarity of the microscopic model. The model implies that in democratic systems, stabilization of one subsystem is equivalent to global scrambling. We use these results to study scrambling of infalling perturbations in black hole backgrounds, and argue that the near horizon running coupling constants are connected to entanglement evolution of single particle perturbations in democratic...

  16. Photonics walking up a human hair

    Science.gov (United States)

    Zeng, Hao; Parmeggiani, Camilla; Martella, Daniele; Wasylczyk, Piotr; Burresi, Matteo; Wiersma, Diederik S.

    2016-03-01

    While animals have access to sugars as energy source, this option is generally not available to artificial machines and robots. Energy delivery is thus the bottleneck for creating independent robots and machines, especially on micro- and nano- meter length scales. We have found a way to produce polymeric nano-structures with local control over the molecular alignment, which allowed us to solve the above issue. By using a combination of polymers, of which part is optically sensitive, we can create complex functional structures with nanometer accuracy, responsive to light. In particular, this allowed us to realize a structure that can move autonomously over surfaces (it can "walk") using the environmental light as its energy source. The robot is only 60 μm in total length, thereby smaller than any known terrestrial walking species, and it is capable of random, directional walking and rotating on different dry surfaces.

  17. Humanoid robot Lola: design and walking control.

    Science.gov (United States)

    Buschmann, Thomas; Lohmeier, Sebastian; Ulbrich, Heinz

    2009-01-01

    In this paper we present the humanoid robot LOLA, its mechatronic hardware design, simulation and real-time walking control. The goal of the LOLA-project is to build a machine capable of stable, autonomous, fast and human-like walking. LOLA is characterized by a redundant kinematic configuration with 7-DoF legs, an extremely lightweight design, joint actuators with brushless motors and an electronics architecture using decentralized joint control. Special emphasis was put on an improved mass distribution of the legs to achieve good dynamic performance. Trajectory generation and control aim at faster, more flexible and robust walking. Center of mass trajectories are calculated in real-time from footstep locations using quadratic programming and spline collocation methods. Stabilizing control uses hybrid position/force control in task space with an inner joint position control loop. Inertial stabilization is achieved by modifying the contact force trajectories.

  18. Getting mobile with a walking-help

    DEFF Research Database (Denmark)

    Krummheuer, Antonia Lina; Raudaskoski, Pirkko Liisa

    . People suffering from severe acquired brain injury often have to find new ways to carry out mundane embodied practices such as walking, eating etc., because their muscles cannot or have “forgotten” how to conduct the movement or parts of it. Our study is based on video-recordings of situations in which...... of the technology (e.g. Gaver 1996), the bodily affordances (e.g. Sheller 2011) of the user and, furthermore, the scaffolding by an accompanying helper. The paper will discuss how movement as an enabled experience can be analysed as an entanglement of these three aspects. To do that, the situations of walk...... are understood as a Latourian socio-material networks or assemblages that perform an action, rather than depicting the walking help as an object of human actions (Latour 2005). From that constellation a publicly observable ‘mobile with’ (Goffman 1971) can sometimes emerge (when the support is mostly linguistic...

  19. Gaussian Networks Generated by Random Walks

    CERN Document Server

    Javarone, Marco Alberto

    2014-01-01

    We propose a random walks based model to generate complex networks. Many authors studied and developed different methods and tools to analyze complex networks by random walk processes. Just to cite a few, random walks have been adopted to perform community detection, exploration tasks and to study temporal networks. Moreover, they have been used also to generate scale-free networks. In this work, we define a random walker that plays the role of "edges-generator". In particular, the random walker generates new connections and uses these ones to visit each node of a network. As result, the proposed model allows to achieve networks provided with a Gaussian degree distribution, and moreover, some features as the clustering coefficient and the assortativity show a critical behavior. Finally, we performed numerical simulations to study the behavior and the properties of the cited model.

  20. Modeling, simulation and optimization of bipedal walking

    CERN Document Server

    Berns, Karsten

    2013-01-01

    The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are Modeling techniques for anthropomorphic bipedal walking systems Optimized walking motions for different objective functions Identification of objective functions from measurements Simulation and optimization approaches for humanoid robots Biologically inspired con...

  1. Quantum walk search through potential barriers

    Science.gov (United States)

    Wong, Thomas G.

    2016-12-01

    An ideal quantum walk transitions from one vertex to another with perfect fidelity, but in physical systems, the particle may be hindered by potential energy barriers. Then the particle has some amplitude of tunneling through the barriers, and some amplitude of staying put. We investigate the algorithmic consequence of such barriers for the quantum walk formulation of Grover’s algorithm. We prove that the failure amplitude must scale as O(1/\\sqrt{N}) for search to retain its quantum O(\\sqrt{N}) runtime; otherwise, it searches in classical O(N) time. Thus searching larger ‘databases’ requires increasingly reliable hop operations or error correction. This condition holds for both discrete- and continuous-time quantum walks.

  2. Diffraction and interference of walking drops

    Science.gov (United States)

    Pucci, Giuseppe; Harris, Daniel M.; Bush, John W. M.

    2016-11-01

    A decade ago, Yves Couder and Emmanuel Fort discovered a wave-particle association on the macroscopic scale: a drop can bounce indefinitely on a vibrating bath of the same liquid and can be piloted by the waves that it generates. These walking droplets have been shown to exhibit several quantum-like features, including single-particle diffraction and interference. Recently, the original diffraction and interference experiments of Couder and Fort have been revisited and contested. We have revisited this system using an improved experimental set-up, and observed a strong dependence of the behavior on system parameters, including drop size and vibrational forcing. In both the single- and the double-slit geometries, the diffraction pattern is dominated by the interaction of the walking droplet with a planar boundary. Critically, in the double-slit geometry, the walking droplet is influenced by both slits by virtue of its spatially extended wave field. NSF support via CMMI-1333242.

  3. Effect of prolonged free-walking fatigue on gait and physiological rhythm.

    Science.gov (United States)

    Yoshino, Kohzoh; Motoshige, Tomoko; Araki, Tsutomu; Matsuoka, Katsunori

    2004-08-01

    This study examined the ways in which gait patterns and physiological rhythms such as those of muscle activity (tibialis anterior (TA) and biceps femoris (BF)) and cardiac activity are affected by the fatigue induced by prolonged free walking. Twelve normal subjects who walked for 3 h at their preferred pace were divided into two groups according to whether their mean gait cycle time (reciprocal of stride rate) during the second 90 min was higher (Group A: n=8) or lower (Group B: n=4) than that during the first 90 min. For Group A, the level of subjective fatigue during the walking task was significantly higher and the heart rate at rest was significantly lower than Group B. In Group A, prolonged walking significantly decreased the mean power frequency of the electromyography from TA, increased the variability of gait rhythm, decreased the largest Lyapunov exponent of the vertical component of back-waist acceleration, and decreased the amplitude of the vertical component of back-waist acceleration. Taking the onset timings of these changes into account, we propose that subjects who tire easily during prolonged walking first show local muscle fatigue at TA followed by instability of gait rhythm and then they slow their gait rhythm to enhance local dynamic stability. For both groups we constructed a physical fatigue index described by linear regression of gait and physiological variables. When we compared the subjective fatigue level with the fatigue level predicted using the index, we obtained a relatively high correlation coefficient for both groups (r=0.77).

  4. Stride Counting in Human Walking and Walking Distance Estimation Using Insole Sensors

    Science.gov (United States)

    Truong, Phuc Huu; Lee, Jinwook; Kwon, Ae-Ran; Jeong, Gu-Min

    2016-01-01

    This paper proposes a novel method of estimating walking distance based on a precise counting of walking strides using insole sensors. We use an inertial triaxial accelerometer and eight pressure sensors installed in the insole of a shoe to record walkers’ movement data. The data is then transmitted to a smartphone to filter out noise and determine stance and swing phases. Based on phase information, we count the number of strides traveled and estimate the movement distance. To evaluate the accuracy of the proposed method, we created two walking databases on seven healthy participants and tested the proposed method. The first database, which is called the short distance database, consists of collected data from all seven healthy subjects walking on a 16 m distance. The second one, named the long distance database, is constructed from walking data of three healthy subjects who have participated in the short database for an 89 m distance. The experimental results show that the proposed method performs walking distance estimation accurately with the mean error rates of 4.8% and 3.1% for the short and long distance databases, respectively. Moreover, the maximum difference of the swing phase determination with respect to time is 0.08 s and 0.06 s for starting and stopping points of swing phases, respectively. Therefore, the stride counting method provides a highly precise result when subjects walk. PMID:27271634

  5. Stride Counting in Human Walking and Walking Distance Estimation Using Insole Sensors

    Directory of Open Access Journals (Sweden)

    Phuc Huu Truong

    2016-06-01

    Full Text Available This paper proposes a novel method of estimating walking distance based on a precise counting of walking strides using insole sensors. We use an inertial triaxial accelerometer and eight pressure sensors installed in the insole of a shoe to record walkers’ movement data. The data is then transmitted to a smartphone to filter out noise and determine stance and swing phases. Based on phase information, we count the number of strides traveled and estimate the movement distance. To evaluate the accuracy of the proposed method, we created two walking databases on seven healthy participants and tested the proposed method. The first database, which is called the short distance database, consists of collected data from all seven healthy subjects walking on a 16 m distance. The second one, named the long distance database, is constructed from walking data of three healthy subjects who have participated in the short database for an 89 m distance. The experimental results show that the proposed method performs walking distance estimation accurately with the mean error rates of 4.8% and 3.1% for the short and long distance databases, respectively. Moreover, the maximum difference of the swing phase determination with respect to time is 0.08 s and 0.06 s for starting and stopping points of swing phases, respectively. Therefore, the stride counting method provides a highly precise result when subjects walk.

  6. Nordic walking and chronic low back pain

    DEFF Research Database (Denmark)

    Morsø, Lars; Hartvigsen, Jan; Puggaard, Lis

    2006-01-01

    Low Back Pain is a major public health problem all over the western world. Active approaches including exercise in the treatment of low back pain results in better outcomes for patients, but it is not known exactly which types of back exercises are most beneficial or whether general physical....... Until now no studies have been performed to investigate whether Nordic Walking has beneficial effects in relation to low back pain. The primary aim of this study is to investigate whether supervised Nordic Walking can reduce pain and improve function in a population of chronic low back pain patients...

  7. Movement Behavior of High-Heeled Walking

    DEFF Research Database (Denmark)

    Alkjær, Tine; Raffalt, Peter Christian; Petersen, Nicolas Caesar

    2012-01-01

    The human locomotor system is flexible and enables humans to move without falling even under less than optimal conditions. Walking with high-heeled shoes constitutes an unstable condition and here we ask how the nervous system controls the ankle joint in this situation? We investigated the movement...... behavior of high-heeled and barefooted walking in eleven female subjects. The movement variability was quantified by calculation of approximate entropy (ApEn) in the ankle joint angle and the standard deviation (SD) of the stride time intervals. Electromyography (EMG) of the soleus (SO) and tibialis...

  8. On d-Walk Regular Graphs

    OpenAIRE

    Estrada, Ernesto; de la Pena, Jose A.

    2013-01-01

    Let G be a graph with set of vertices 1,...,n and adjacency matrix A of size nxn. Let d(i,j)=d, we say that f_d:N->N is a d-function on G if for every pair of vertices i,j and k>=d, we have a_ij^(k)=f_d(k). If this function f_d exists on G we say that G is d-walk regular. We prove that G is d-walk regular if and only if for every pair of vertices i,j at distance

  9. Random walk term weighting for information retrieval

    DEFF Research Database (Denmark)

    Blanco, R.; Lioma, Christina

    2007-01-01

    We present a way of estimating term weights for Information Retrieval (IR), using term co-occurrence as a measure of dependency between terms.We use the random walk graph-based ranking algorithm on a graph that encodes terms and co-occurrence dependencies in text, from which we derive term weights...... that represent a quantification of how a term contributes to its context. Evaluation on two TREC collections and 350 topics shows that the random walk-based term weights perform at least comparably to the traditional tf-idf term weighting, while they outperform it when the distance between co-occurring terms...

  10. Effect of body awareness training on balance and walking ability in chronic stroke patients: a randomized controlled trial.

    Science.gov (United States)

    Bang, Dae-Hyouk; Cho, Hyuk-Shin

    2016-01-01

    [Purpose] To investigate the effects of body awareness training on balance and walking ability in chronic stroke patients. [Subjects] The subjects were randomly assigned to a body awareness training group (n=6) and a control group (n=6). [Methods] Patients in the body awareness training group received body awareness training for 20 minutes, followed by walking training for 30 minutes a day, 5 days a week for 4 weeks. The control group received walking training for 30 minutes a day, 5 days a week for 4 weeks. [Results] After the intervention, both groups showed significant improvements in the Berg Balance Scale, Timed Up and Go Test, and 10 m walk test compared with baseline results. The body awareness training group showed more significant improvements in the Berg Balance Scale and Timed Up and Go Test than the control group. There was no significant difference in the 10 m walk test between the groups. [Conclusion] The results of this study suggest that body awareness training has a positive effect on balance in patients with chronic stroke.

  11. Environmental factors influencing older adults’ walking for transportation: a study using walk-along interviews

    Directory of Open Access Journals (Sweden)

    Van Cauwenberg Jelle

    2012-07-01

    Full Text Available Abstract Background Current knowledge on the relationship between the physical environment and walking for transportation among older adults (≥ 65 years is limited. Qualitative research can provide valuable information and inform further research. However, qualitative studies are scarce and fail to include neighborhood outings necessary to study participants’ experiences and perceptions while interacting with and interpreting the local social and physical environment. The current study sought to uncover the perceived environmental influences on Flemish older adults’ walking for transportation. To get detailed and context-sensitive environmental information, it used walk-along interviews. Methods Purposeful convenience sampling was used to recruit 57 older adults residing in urban or semi-urban areas. Walk-along interviews to and from a destination (e.g. a shop located within a 15 minutes’ walk from the participants’ home were conducted. Content analysis was performed using NVivo 9 software (QSR International. An inductive approach was used to derive categories and subcategories from the data. Results Data were categorized in the following categories and subcategories: access to facilities (shops & services, public transit, connectivity, walking facilities (sidewalk quality, crossings, legibility, benches, traffic safety (busy traffic, behavior of other road users, familiarity, safety from crime (physical factors, other persons, social contacts, aesthetics (buildings, natural elements, noise & smell, openness, decay and weather. Conclusions The findings indicate that to promote walking for transportation a neighborhood should provide good access to shops and services, well-maintained walking facilities, aesthetically appealing places, streets with little traffic and places for social interaction. In addition, the neighborhood environment should evoke feelings of familiarity and safety from crime. Future quantitative studies should

  12. Knee Muscle Forces during Walking and Running in Patellofemoral Pain Patients and Pain-Free Controls

    Science.gov (United States)

    Besier, Thor F.; Fredericson, Michael; Gold, Garry E.; Beaupré, Gary S.; Delp, Scott L.

    2009-01-01

    One proposed mechanism of patellofemoral pain, increased stress in the joint, is dependent on forces generated by the quadriceps muscles. Describing causal relationships between muscle forces, tissue stresses, and pain is difficult due to the inability to directly measure these variables in vivo. The purpose of this study was to estimate quadriceps forces during walking and running in a group of male and female patients with patellofemoral pain (n=27, 16 female; 11 male) and compare these to pain-free controls (n=16, 8 female; 8 male). Subjects walked and ran at self-selected speeds in a gait laboratory. Lower limb kinematics and electromyography (EMG) data were input to an EMG-driven musculoskeletal model of the knee, which was scaled and calibrated to each individual to estimate forces in 10 muscles surrounding the joint. Compared to controls, the patellofemoral pain group had greater co-contraction of quadriceps and hamstrings (p=0.025) and greater normalized muscle forces during walking, even though the net knee moment was similar between groups. Muscle forces during running were similar between groups, but the net knee extension moment was less in the patellofemoral pain group compared to controls. Females displayed 30-50% greater normalized hamstring and gastrocnemius muscle forces during both walking and running compared to males (pjoint contact forces and joint stresses than pain-free subjects. PMID:19268945

  13. Musical motor feedback (MMF) in walking hemiparetic stroke patients: randomized trials of gait improvement.

    Science.gov (United States)

    Schauer, Michael; Mauritz, Karl-Heinz

    2003-11-01

    To demonstrate the effect of rhythmical auditory stimulation in a musical context for gait therapy in hemiparetic stroke patients, when the stimulation is played back measure by measure initiated by the patient's heel-strikes (musical motor feedback). Does this type of musical feedback improve walking more than a less specific gait therapy? The randomized controlled trial considered 23 registered stroke patients. Two groups were created by randomization: the control group received 15 sessions of conventional gait therapy and the test group received 15 therapy sessions with musical motor feedback. Inpatient rehabilitation hospital. Median post-stroke interval was 44 days and the patients were able to walk without technical aids with a speed of approximately 0.71 m/s. Gait velocity, step duration, gait symmetry, stride length and foot rollover path length (heel-on-toe-off distance). The test group showed more mean improvement than the control group: stride length increased by 18% versus 0%, symmetry deviation decreased by 58% versus 20%, walking speed increased by 27% versus 4% and rollover path length increased by 28% versus 11%. Musical motor feedback improves the stroke patient's walk in selected parameters more than conventional gait therapy. A fixed memory in the patient's mind about the song and its timing may stimulate the improvement of gait even without the presence of an external pacemaker.

  14. Comparison of walking overground and in a Computer Assisted Rehabilitation Environment (CAREN in individuals with and without transtibial amputation

    Directory of Open Access Journals (Sweden)

    Gates Deanna H

    2012-11-01

    Full Text Available Abstract Background Due to increased interest in treadmill gait training, recent research has focused on the similarities and differences between treadmill and overground walking. Most of these studies have tested healthy, young subjects rather than impaired populations that might benefit from such training. These studies also do not include optic flow, which may change how the individuals integrate sensory information when walking on a treadmill. This study compared overground walking to treadmill walking in a computer assisted virtual reality environment (CAREN in individuals with and without transtibial amputations (TTA. Methods Seven individuals with traumatic TTA and 27 unimpaired controls participated. Subjects walked overground and on a treadmill in a CAREN at a normalized speed. The CAREN applied optic flow at the same speed that the subject walked. Temporal-spatial parameters, full body kinematics, and kinematic variability were collected during all trials. Results Both subject groups decreased step time and control subjects decreased step length when walking in the CAREN. Differences in lower extremity kinematics were small (○ and did not exceed the minimal detectable change values for these measures. Control subjects exhibited decreased transverse and frontal plane range of motion of the pelvis and trunk when walking in the CAREN, while patients with TTA did not. Both groups exhibited increased step width variability during treadmill walking in the CAREN, but only minor changes in kinematic variability. Conclusions The results of this study suggest that treadmill training in a virtual environment should be similar enough to overground that changes should carry over. Caution should be made when comparing step width variability and step time results from studies utilizing a treadmill to those overground.

  15. The energy expenditure of people with spinal cord injury whilst walking compared to an able-bodied population

    Directory of Open Access Journals (Sweden)

    Jana Vosloo

    2016-02-01

    Full Text Available Background: In the field of spinal cord injury (SCI research there is an emphasis on the ability to ambulate.Purpose: To determine the ambulation energy expenditure (EE and factors that affect ambulation EE in SCI participants compared to able-bodied participants.Methods: This was a cross-sectional study. Participants were recruited from seven SCI rehabilitation units within the Johannesburg area. The following were used: demographic questionnaire to capture participants’ characteristics, modified Ashworth scale for spasticity; goniometer for range of movement (ROM; American Spinal Injury Association (ASIA scale for patient classification; accelerometer for EE and the six-minute walk test (6MWT for endurance. Characteristics of the study participants were summarised using descriptive statistics. Data were analysed as follows: two-sample t-test for comparison between the able-bodied and SCI sample and Pearson product moment correlations for relationship between identified factors and EE.Results: Participants comprised 45 in the SCI group and 21 in the able-bodied group. The mean energy expenditure per metre (EE/m for the SCI participants was 0.33 (± 0.29 calories compared to 0.08 (± 0.02 calories for the able-bodied participants. A decrease in walking velocity resulted in an increase in EE. For SCI participants, every decrease in degree of hip flexion ROM resulted in a 0.003 increase in EE/m walked. A unit decrease in velocity resulted in an increase of 0.41 in EE/m walked. Energy expenditure per metre decreased from ASIA A to ASIA D. Crutch walking utilised 0.34 calories per metre less energy than walking frames (p = 0.03.Conclusion: Based on this study’s findings, factors to consider in order to maximise energy efficiency whilst walking are maintaining hip flexion ROM and optimising velocity of walking.Keywords: Energy expenditure; Factors affecting energy expenditure; Range of motion; Walking Velocity

  16. Influence of the swing ankle angle on walking stability for a passive dynamic walking robot with flat feet

    OpenAIRE

    Xizhe Zang; Xinyu Liu; Yixiang Liu; Sajid Iqbal; Jie Zhao

    2016-01-01

    To achieve high walking stability for a passive dynamic walking robot is not easy. In this article, we aim to investigate whether the walking performance for a passive dynamic walking robot can be improved by just simply changing the swing ankle angle before impact. To validate this idea, a passive bipedal walking model with two straight legs, two flat feet, a hip joint, and two ankle joints was built in this study. The walking dynamics that contains double stance phase was derived. By numeri...

  17. COMPARISON OF THE CONCENTRIC TORQUE OF KNEE MUSCLES AND TIMED-WALKING TEST IN HEALTHY AND LOW GRADE TIBIOFEMORAL OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    H. Bagheri

    2007-07-01

    Full Text Available The aim of study was to investigate and compare the concentric torque of Quadriceps and Hamstring muscles and Timed-Walking test in two groups. Thus, one group of healthy subjects and one group of patients with low grade of tibiofemoral osteoarthritis (OA were selected. Concentric torque of Quadriceps and Hamstring were measured in both groups. Besides, pain measurement, Timed-Walking test, range of motion and the muscle bulk of thigh were assessed in both groups. The independent t-test revealed significant differences between the two groups with regard to concentric torques and Timed-Walking test. However, no significant difference in range of motion and the muscle bulk was seen. In conclusion, patients with low grade of osteoarthritis and minimum clinical signs had weaker muscles and functional limitation in comparison with the matched healthy individuals.

  18. Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

    Directory of Open Access Journals (Sweden)

    Ronny Geva

    Full Text Available Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9 for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p < .005, along with increases, counter to the general reduction trend, in skills that serve recruitment of external resources [socio-communication bids before speech (r = -.696, p < .01, and speech bids before walking; r = .729, p < .01]. Integration of these proactive changes using a computational approach yielded an even stronger link, underscoring internal resource reallocation as a facilitator of walking initiation (r = .901, p<0

  19. Pilates exercise training vs. physical therapy for improving walking and balance in people with multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Kalron, Alon; Rosenblum, Uri; Frid, Lior; Achiron, Anat

    2017-03-01

    Evaluate the effects of a Pilates exercise programme on walking and balance in people with multiple sclerosis and compare this exercise approach to conventional physical therapy sessions. Randomized controlled trial. Multiple Sclerosis Center, Sheba Medical Center, Tel-Hashomer, Israel. Forty-five people with multiple sclerosis, 29 females, mean age (SD) was 43.2 (11.6) years; mean Expanded Disability Status Scale (S.D) was 4.3 (1.3). Participants received 12 weekly training sessions of either Pilates ( n=22) or standardized physical therapy ( n=23) in an outpatient basis. Spatio-temporal parameters of walking and posturography parameters during static stance. Functional tests included the Time Up and Go Test, 2 and 6-minute walk test, Functional Reach Test, Berg Balance Scale and the Four Square Step Test. In addition, the following self-report forms included the Multiple Sclerosis Walking Scale and Modified Fatigue Impact Scale. At the termination, both groups had significantly increased their walking speed ( P=0.021) and mean step length ( P=0.023). According to the 2-minute and 6-minute walking tests, both groups at the end of the intervention program had increased their walking speed. Mean (SD) increase in the Pilates and physical therapy groups were 39.1 (78.3) and 25.3 (67.2) meters, respectively. There was no effect of group X time in all instrumented and clinical balance and gait measures. Pilates is a possible treatment option for people with multiple sclerosis in order to improve their walking and balance capabilities. However, this approach does not have any significant advantage over standardized physical therapy.

  20. The role of the built environment in explaining educational inequalities in walking and cycling among adults in the Netherlands.

    Science.gov (United States)

    van Wijk, Daniël C; Groeniger, Joost Oude; van Lenthe, Frank J; Kamphuis, Carlijn B M

    2017-03-31

    This study examined whether characteristics of the residential built environment (i.e. population density, level of mixed land use, connectivity, accessibility of facilities, accessibility of green) contributed to educational inequalities in walking and cycling among adults. Data from participants (32-82 years) of the 2011 survey of the Dutch population-based GLOBE study were used (N = 2375). Highest attained educational level (independent variable) and walking for transport, cycling for transport, walking in leisure time and cycling in leisure time (dependent variables) were self-reported in the survey. GIS-systems were used to obtain spatial data on residential built environment characteristics. A four-step mediation-based analysis with log-linear regression models was used to examine to contribution of the residential built environment to educational inequalities in walking and cycling. As compared to the lowest educational group, the highest educational group was more likely to cycle for transport (RR 1.13, 95% CI 1.04-1.23), walk in leisure time (RR 1.12, 95% CI 1.04-1.21), and cycle in leisure time (RR 1.12, 95% CI 1.03-1.22). Objective built environment characteristics were related to these outcomes, but contributed minimally to educational inequalities in walking and cycling. On the other hand, compared to the lowest educational group, the highest educational group was less likely to walk for transport (RR 0.91, 95% CI 0.82-1.01), which could partly be attributed to differences in the built environment. This study found that objective built environment characteristics contributed minimally to educational inequalities in walking and cycling in the Netherlands.

  1. Obesity does not increase external mechanical work per kilogram body mass during walking.

    Science.gov (United States)

    Browning, Raymond C; McGowan, Craig P; Kram, Rodger

    2009-10-16

    Walking is the most common type of physical activity prescribed for the treatment of obesity. The net metabolic rate during level walking (W/kg) is approximately 10% greater in obese vs. normal weight adults. External mechanical work (W(ext)) is one of the primary determinants of the metabolic cost of walking, but the effects of obesity on W(ext) have not been clearly established. The purpose of this study was to compare W(ext) between obese and normal weight adults across a range of walking speeds. We hypothesized that W(ext) (J/step) would be greater in obese adults but W(ext) normalized to body mass would be similar in obese and normal weight adults. We collected right leg three-dimensional ground reaction forces (GRF) while twenty adults (10 obese, BMI=35.6 kg/m(2) and 10 normal weight, BMI=22.1 kg/m(2)) walked on a level, dual-belt force measuring treadmill at six speeds (0.50-1.75 m/s). We used the individual limb method (ILM) to calculate external work done on the center of mass. Absolute W(ext) (J/step) was greater in obese vs. normal weight adults at each walking speed, but relative W(ext) (J/step/kg) was similar between the groups. Step frequencies were not different. These results suggest that W(ext) is not responsible for the greater metabolic cost of walking (W/kg) in moderately obese adults.

  2. Effects of Synchronization between Cardiac and Locomotor Rhythms on Oxygen Pulse during Walking.

    Science.gov (United States)

    Takeuchi, Shinta; Nishida, Yusuke; Mizushima, Takashi

    2014-12-01

    The oObjective of the study was to investigate whether the occurrence of cardiac-locomotor synchronization (CLS) affects oxygen pulse (O2 pulse, mL/beat) during walking. Twelve healthy men were studied under two treadmill protocols. The CLS protocol involved subjects walking at a frequency of their heart rate (HR) to induce CLS. The free protocol (reference) involved subjects walking at a self-selected cadence. The treadmill load was equal between the two protocols and was adjusted so that the subject's HR was maintained at approximately 120 bpm. Electrocardiographic signals, foot switch signals, and oxygen consumption (VO2) were measured continuously for 10 min after the heart rate reached a steady state. VO2, O2 pulse, and mean HR were calculated. VO2 and O2 pulse were significantly higher in subjects in the CLS protocol compared to those in the free protocol. However, mean HR was not different between the two groups. The synchronization strength was significantly related to the increase in O2 pulse in subjects in the CLS protocol compared with those in the free protocol. These results suggest that the occurrence of CLS enhances O2 pulse by increasing the strength of CLS during walking. Key PointsTwelve healthy men walked at a frequency of their heart rate (CLS protocol) and at a self-selected cadence (free protocol).Walking at the frequency of heart rate would induce the CLS by entrainment.Oxygen pulse was significantly higher in subjects in the CLS protocol compared to those in the free protocol.The occurrence of CLS enhances oxygen pulse by increasing the strength of CLS during walking.

  3. [Home falls in infants before walking acquisition].

    Science.gov (United States)

    Claudet, I; Gurrera, E; Honorat, R; Rekhroukh, H; Casasoprana, A; Grouteau, E

    2013-05-01

    Minor head trauma is frequent among infants and leads to numerous visits to emergency departments for neurological assessment to evaluate the value of cerebral CT scan with the risk for traumatic brain injuries (TBI). To analyze the epidemiological characteristics of nonwalking infants admitted after falling at home and to analyze associated factors for skull fractures and TBI. Between January 2007 and December 2011, all children aged 9 months or younger and admitted after a home fall to the pediatric emergency unit of a tertiary children's hospital were included. The data collected were age, sex, weight and height, body mass index; geographic origin, referral or direct admission, mode of transportation; month, day and time of admission; causes of the fall, alleged fall height, presence of an eyewitness, type of landing surface; Glasgow Coma Scale (GCS) score, application of the head trauma protocol, location and type of injuries, cerebral CT scan results, length of hospital stay, progression, and neglect or abuse situations. DESCRIPTIVE ANALYSIS: within the study period, 1910 infants were included. Fifty-four percent of children were aged less than 6 months with a slight male prevalence (52%). Falls from parental bed and infant carriers accounted for the most frequent fall circumstances. GCS score on admission was equal to 14 or 15 in 99% of cases. A cerebral CT scan was performed in 34% of children and detected 104 skull fractures and 55 TBI. Infants aged less than 1 month had the highest rate of TBI (8.5%). Eleven percent of patients were hospitalized. A situation of abuse was identified in 51 infants (3%). UNIVARIATE ANALYSIS: Male children and infants aged less than 3 months had a higher risk of skull fractures (P = 0.03 and P = 0.0003, respectively). In the TBI group, children were younger (3.8 ± 2.6 months versus 5.4 ± 2.5 months, P walking acquisition, children are particularly vulnerable and have the highest rate of TBI after a vertical fall. In this age

  4. Probability of walking in children with cerebral palsy in Europe

    DEFF Research Database (Denmark)

    Beckung, E.; Hagberg, G.; Uldall, P.

    2008-01-01

    OBJECTIVES: The purpose of this work was to describe walking ability in children with cerebral palsy from the Surveillance of Cerebral Palsy in Europe common database through 21 years and to examine the association between walking ability and predicting factors. PATIENTS AND METHODS: Anonymous data...... on 10042 children with cerebral palsy born between 1976 and 1996 were gathered from 14 European centers; 9012 patients were eligible for the analyses. RESULTS: Unaided walking as the primary way of walking at 5 years of age was reported for 54%, walking with assistive devices was reported for 16......%, and no walking ability was reported for 30%. The proportion of children who were unable to walk was rather stable over time in all of the centers, with a mean proportion of 28%. Walking ability related significantly to cerebral palsy types, that is, spastic unilateral, spastic bilateral, dyskinetic, and ataxic...

  5. Invertebrate neurobiology: sensory processing in reverse for backward walking.

    Science.gov (United States)

    Zill, Sasha N

    2007-06-19

    Humans and many other animals can readily walk forward or backward. In insects, the nervous system changes the effects of sense organs that signal forces on a leg when the direction of walking is reversed.

  6. Effect of inspiratory muscle training on respiratory capacity and walking ability with subacute stroke patients: a randomized controlled pilot trial.

    Science.gov (United States)

    Jung, Kyeong-Man; Bang, Dae-Hyouk

    2017-02-01

    [Purpose] To investigate the effects of inspiratory muscle training on respiratory capacity and walking ability in subacute stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received inspiratory muscle training for 30 minutes (six sets of five-minutes) and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. There were significant between-group differences for the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. No statistically significant differences were observed for measures of saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] These findings gave some indications that inspiratory muscle training may benefit in patients with subacute stroke, and it is feasible to be included in rehabilitation program with this population.

  7. CanWalk: a feasibility study with embedded randomised controlled trial pilot of a walking intervention for people with recurrent or metastatic cancer

    Science.gov (United States)

    Tsianakas, Vicki; Ream, Emma; Van Hemelrijck, Mieke; Purushotham, Arnie; Mucci, Lorelei; Green, James S A; Fewster, Jacquetta; Armes, Jo

    2017-01-01

    Objectives Walking is an adaptable, inexpensive and accessible form of physical activity. However, its impact on quality of life (QoL) and symptom severity in people with advanced cancer is unknown. This study aimed to assess the feasibility and acceptability of a randomised controlled trial (RCT) of a community-based walking intervention to enhance QoL in people with recurrent/metastatic cancer. Design We used a mixed-methods design comprising a 2-centre RCT and nested qualitative interviews. Participants Patients with advanced breast, prostate, gynaecological or haematological cancers randomised 1:1 between intervention and usual care. Intervention The intervention comprised Macmillan's ‘Move More’ information, a short motivational interview with a recommendation to walk for at least 30 min on alternate days and attend a volunteer-led group walk weekly. Outcomes We assessed feasibility and acceptability of the intervention and RCT by evaluating study processes (rates of recruitment, consent, retention, adherence and adverse events), and using end-of-study questionnaires and qualitative interviews. Patient-reported outcome measures (PROMs) assessing QoL, activity, fatigue, mood and self-efficacy were completed at baseline and 6, 12 and 24 weeks. Results We recruited 42 (38%) eligible participants. Recruitment was lower than anticipated (goal n=60), the most commonly reported reason being unable to commit to walking groups (n=19). Randomisation procedures worked well with groups evenly matched for age, sex and activity. By week 24, there was a 45% attrition rate. Most PROMs while acceptable were not sensitive to change and did not capture key benefits. Conclusions The intervention was acceptable, well tolerated and the study design was judged acceptable and feasible. Results are encouraging and demonstrate that exercise was popular and conveyed benefit to participants. Consequently, an effectiveness RCT is warranted, with some modifications to the

  8. Evaluating effects of method of administration on Walking Impairment Questionnaire.

    Science.gov (United States)

    Coyne, Karin S; Margolis, Mary Kay; Gilchrist, Kim A; Grandy, Susan P; Hiatt, William R; Ratchford, Andrea; Revicki, Dennis A; Weintraub, William S; Regensteiner, Judith G

    2003-08-01

    Intermittent claudication resulting from peripheral arterial disease (PAD) can substantially impair walking function. The Walking Impairment Questionnaire (WIQ) assesses patient self-reported difficulty in walking. Currently this questionnaire is validated for interviewer administration only. Since this can be burdensome in a large clinical trial, we examined the effects of alternative methods of administration on patient responses on the WIQ. The WIQ, which consists of four subscales (pain severity, distance, speed, stairs), was modified to be self-administered or interviewer-administered by telephone. Patients with PAD were recruited from two sites and randomized into two groups: in group 1 the WIQ was self-administered, then telephone-administered; in group 2 the WIQ was telephone-administered, then self-administered. The two administrations occurred 4 to 7 days apart. Additional measures (SF-36, EQ-5D, and PAD symptom scale) and clinical data were included to further assess the validity of the WIQ and symptoms in patients with claudication. Telephone interviews were conducted by trained interviewers using standardized scripts. Two-week test-retest reliability was assessed for both the self-administered WIQ (group 1) and the telephone-administered WIQ (group 2). Sixty patients were recruited at two sites (n = 30 per group). Seventy-eight percent were men; mean patient age was 67.1 years; and 83% of patients were white. Mean duration of PAD symptoms was 6.8 years. No significant differences were observed in WIQ subscale scores between self administration and telephone administration. No interaction effects between order and method of administration were detected. Cronbach alpha for distance, speed, and stair-climbing subscales ranged from 0.82 to 0.94. Correlations among WIQ subscales and the symptom scale were good (r = -0.34 to -0.57). Correlations of WIQ subscales with physical health subscales of the SF-36 (r = 0.24-0.59) were higher than for mental health

  9. Mesonic spectroscopy of Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino

    2010-01-01

    We investigate the structure and the novel emerging features of the mesonic non-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD...

  10. Exact Random Walk Distributions using Noncommutative Geometry

    CERN Document Server

    Bellissard, J; Barelli, A; Claro, F; Bellissard, Jean; Camacho, Carlos J; Barelli, Armelle; Claro, Francisco

    1997-01-01

    Using the results obtained by the non commutative geometry techniques applied to the Harper equation, we derive the areas distribution of random walks of length $ N $ on a two-dimensional square lattice for large $ N $, taking into account finite size contributions.

  11. Second annual Dog Walk Against Cancer scheduled

    OpenAIRE

    Douglas, Jeffrey S.

    2005-01-01

    The second annual "Dog Walk Against Cancer" will be held from 10 a.m. to 2 p.m. Saturday, April 9, on the grounds of the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech in Blacksburg. The event is open to the public and will be held in conjunction with the college's annual "Open House."

  12. Influence of moving visual surroundings on walking

    NARCIS (Netherlands)

    Mert, A.; Hak, L.; Bles, W.

    2011-01-01

    Introduction: Balance is negatively influenced by optokinetic stimuli. Fall research with these stimuli has been done with standing subjects. Less is known of the influence these stimuli have on risk of falling while walking. The objective of this study was to qualitatively investigate the influence

  13. Random walk centrality for temporal networks

    CERN Document Server

    Rocha, Luis Enrique Correa

    2014-01-01

    Nodes can be ranked according to their relative importance within the network. Ranking algorithms based on random walks are particularly useful because they connect topological and diffusive properties of the network. Previous methods based on random walks, as for example the PageRank, have focused on static structures. However, several realistic networks are indeed dynamic, meaning that their structure changes in time. In this paper, we propose a centrality measure for temporal networks based on random walks which we call TempoRank. While in a static network, the stationary density of the random walk is proportional to the degree or the strength of a node, we find that in temporal networks, the stationary density is proportional to the in-strength of the so-called effective network. The stationary density also depends on the sojourn probability q which regulates the tendency of the walker to stay in the node. We apply our method to human interaction networks and show that although it is important for a node ...

  14. Autonomous exoskeleton reduces metabolic cost of walking.

    Science.gov (United States)

    Mooney, Luke M; Rouse, Elliott J; Herr, Hugh M

    2014-01-01

    We developed an autonomous powered leg exoskeleton capable of providing large amounts of positive mechanical power to the wearer during powered plantarflexion phase of walking. The autonomous exoskeleton consisted of a winch actuator fasted to the shin which pulled on fiberglass struts attached to a boot. The fiberglass struts formed a rigid extension of the foot when the proximal end of the strut was pulled in forward by the winch actuator. This lightweight, geometric transmission allowed the electric winch actuator to efficiently produce biological levels of power at the ankle joint. The exoskeleton was powered and controlled by lithium polymer batteries and motor controller worn around the waist. Preliminary testing on two subjects walking at 1.4 m/s resulted in the exoskeleton reducing the metabolic cost of walking by 6-11% as compared to not wearing the device. The exoskeleton provided a peak mechanical power of over 180 W at each ankle (mean standard ± deviation) and an average positive mechanical power of 27 ± 1 W total to both ankles, while electrically using 75-89 W of electricity. The batteries (800 g) used in this experiment are estimated to be capable of providing this level of assistance for up to 7 km of walking.

  15. Exploring Space and Place with Walking Interviews

    Science.gov (United States)

    Jones, Phil; Bunce, Griff; Evans, James; Gibbs, Hannah; Hein, Jane Ricketts

    2008-01-01

    This article explores the use of walking interviews as a research method. In spite of a wave of interest in methods which take interviewing out of the "safe," stationary environment, there has been limited work critically examining the techniques for undertaking such work. Curiously for a method which takes an explicitly spatial approach, few…

  16. Floor vibrations due to walking loads

    NARCIS (Netherlands)

    Donkervoort, D.R.; Hoenderkamp, J.C.D.; Oosterhout, G.P.C. van

    1999-01-01

    Traditionally floors are designed for static strength and stiffness. Improved methods of construction and design, using high strength-lightweight materials, have resulted in strong and stiff floors that display unsatisfactory dynamic behaviour when exposed to walking loads. The paper discusses a met

  17. Analysis, Control and Design of Walking Robots

    NARCIS (Netherlands)

    van Oort, Gijs

    2011-01-01

    In this thesis five research questions are discussed that are related to the development of two-legged (bipedal) walking robots. The research questions are categorized in three main topics: analysis, control and actuation and design. The research questions are: - How can we analyze the behavior of a

  18. Go Naked: Diapers Affect Infant Walking

    Science.gov (United States)

    Cole, Whitney G.; Lingeman, Jesse M.; Adolph, Karen E.

    2012-01-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants' poor balance and wide stance. We show that…

  19. The Physics of a Walking Robot

    Science.gov (United States)

    Guemez, J.; Fiolhais, M.

    2013-01-01

    The physics of walking is explored, using a toy as a concrete example and a "toy model" applied to it. Besides using Newton's second law, the problem is also discussed from the thermodynamical perspective. Once the steady state (constant velocity) is achieved, we show that the internal energy of the toy is dissipated as heat in the…

  20. Iterated random walks with shape prior

    DEFF Research Database (Denmark)

    Pujadas, Esmeralda Ruiz; Kjer, Hans Martin; Piella, Gemma;

    2016-01-01

    We propose a new framework for image segmentation using random walks where a distance shape prior is combined with a region term. The shape prior is weighted by a confidence map to reduce the influence of the prior in high gradient areas and the region term is computed with k-means to estimate th...

  1. Random Walk Method for Potential Problems

    Science.gov (United States)

    Krishnamurthy, T.; Raju, I. S.

    2002-01-01

    A local Random Walk Method (RWM) for potential problems governed by Lapalace's and Paragon's equations is developed for two- and three-dimensional problems. The RWM is implemented and demonstrated in a multiprocessor parallel environment on a Beowulf cluster of computers. A speed gain of 16 is achieved as the number of processors is increased from 1 to 23.

  2. Osteogenesis imperfecta in childhood : Prognosis for walking

    NARCIS (Netherlands)

    Engelbert, RHH; Uiterwaal, CSPM; Gulmans, VAM; Pruijs, H; Helders, PJM

    2000-01-01

    Objectives: We studied the predicted value of disease-related characteristics for the ability of children with osteogenesis imperfecta (OI) to walk. Study design: The severity of OI was classified according to Sillence. The parents were asked to report the age at which the child achieved motor miles

  3. Assessment of a Solar System Walk

    Science.gov (United States)

    LoPresto, Michael C.; Murrell, Steven R.; Kirchner, Brian

    2010-01-01

    The idea of sending students and the general public on a walk through a scale model of the solar system in an attempt to instill an appreciation of the relative scales of the sizes of the objects compared to the immense distances between them is certainly not new. A good number of such models exist, including one on the National Mall in…

  4. The Quantum Walk of F. Riesz

    CERN Document Server

    Grunbaum, F A

    2011-01-01

    We exhibit a way to associate a quantum walk (QW) on the non-negative integers to any probability measure on the unit circle. This forces us to consider one step transitions that are not traditionally allowed. We illustrate this in the case of a very interesting measure, originally proposed by F. Riesz for a different purpose.

  5. Osteogenesis imperfecta in childhood : Prognosis for walking

    NARCIS (Netherlands)

    Engelbert, RHH; Uiterwaal, CSPM; Gulmans, VAM; Pruijs, H; Helders, PJM

    Objectives: We studied the predicted value of disease-related characteristics for the ability of children with osteogenesis imperfecta (OI) to walk. Study design: The severity of OI was classified according to Sillence. The parents were asked to report the age at which the child achieved motor

  6. Quantifiying the stability of walking using accelerometers

    NARCIS (Netherlands)

    Waarsing, Jan H.; Mayagoitia, Ruth E.; Veltink, Peter H.

    1996-01-01

    A dynamic analysis method is sought to measure the relative stability of walking, using a triaxial accelerometer. A performance parameter that can be calculated from the data from the accelerometer is defined; it should give a measure of the stability of the subject. It is based on the balancing for

  7. Assessment of a Solar System Walk

    Science.gov (United States)

    LoPresto, Michael C.; Murrell, Steven R.; Kirchner, Brian

    2010-01-01

    The idea of sending students and the general public on a walk through a scale model of the solar system in an attempt to instill an appreciation of the relative scales of the sizes of the objects compared to the immense distances between them is certainly not new. A good number of such models exist, including one on the National Mall in…

  8. Infrared dynamics of Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino;

    2010-01-01

    We study the gauge sector of Minimal Walking Technicolor, which is an SU(2) gauge theory with nf=2 flavors of Wilson fermions in the adjoint representation. Numerical simulations are performed on lattices Nt x Ns^3, with Ns ranging from 8 to 16 and Nt=2Ns, at fixed \\beta=2.25, and varying the fer...

  9. Searching via walking: How to find a marked clique of a complete graph using quantum walks

    Science.gov (United States)

    Hillery, Mark; Reitzner, Daniel; Bužek, Vladimír

    2010-06-01

    We show how a quantum walk can be used to find a marked edge or a marked complete subgraph of a complete graph. We employ a version of a quantum walk, the scattering walk, which lends itself to experimental implementation. The edges are marked by adding elements to them that impart a specific phase shift to the particle as it enters or leaves the edge. If the complete graph has N vertices and the subgraph has K vertices, the particle becomes localized on the subgraph in O(N/K) steps. This leads to a quantum search that is quadratically faster than a corresponding classical search. We show how to implement the quantum walk using a quantum circuit and a quantum oracle, which allows us to specify the resources needed for a quantitative comparison of the efficiency of classical and quantum searches—the number of oracle calls.

  10. Establishing the Range of Perceptually Natural Visual Walking Speeds for Virtual Walking-In-Place Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

    2014-01-01

    from 1.0 to 3.0. Thus, the slowest speed was equal to an estimate of the subjects normal walking speed, while the highest speed was three times greater. The perceived naturalness of the visual speed was assessed using self-reports. The first study compared four different types of movement, namely...... to virtual motion. This paper describes two within-subjects studies performed with the intention of establishing the range of perceptually natural walking speeds for WIP locomotion. In both studies, subjects performed a series of virtual walks while exposed to visual gains (optic flow multipliers) ranging......, no leg movement, walking on a treadmill, and two forms of gestural input for WIP locomotion. The results suggest that WIP locomotion is accompanied by a perceptual distortion of the speed of optic flow. The second study was performed using a 4×2 factorial design and compared four different display field...

  11. Walk1916: Exploring how a mobile walking tour app can provide value for LAMs

    National Research Council Canada - National Science Library

    Cushing, Amber L; Cowan, Benjamin R

    2016-01-01

    ... institutional measures of impact. Understanding the ways in which users value a mobile app that integrates digital collections with a walking tour allows LAMs to develop best practices for use of such tools associated...

  12. Walking Versus Jogging in Stages III and IV of the Bruce Treadmill Test.

    Science.gov (United States)

    Cundiff, D.; Schwane, J.

    Observations during research involving the Bruce Treadmill Test (BTMT) indicating that Stage III for females and Stage IV for males represented speeds which are intermediate between comfortable walking and confortable jogging for many subjects, prompted this study to determine ways to obtain more consistent group results. Twenty-eight subjects…

  13. Do muscle strengthening exercises improve performance in the 6-minute walk test in postmenopausal women?

    Directory of Open Access Journals (Sweden)

    Júlia G. Reis

    Full Text Available BACKGROUND: Walking speed seems to be related to aerobic capacity, lower limb strength, and functional mobility, however it is not clear whether there is a direct relationship between improvement in muscle strength and gait performance in early postmenopausal women. OBJECTIVE: To evaluate the effect of muscle strengthening exercises on the performance of the 6-minute walk test in women within 5 years of menopause. METHODS: The women were randomized into control group (n=31, which performed no exercise, and exercise group (n=27, which performed muscle strengthening exercises. The exercises were performed twice a week for 3 months. The exercise protocol consisted of warm-up, stretching, and strengthening of the quadriceps, hamstring, calf, tibialis anterior, gluteus maximus, and abdominal muscles, followed by relaxation. Muscular strength training started with 60% of 1MR (2 series of 10-15 repetitions, reaching 85% until the end of the 3-month period (4 series of 6 repetitions each. RESULTS: The between-group comparisons pre- and post-intervention did not show any difference in distance walked, heart rate or blood pressure (p>0.05, but showed differences in muscle strength post-intervention, with the exercise group showing greater strength (p CONCLUSION: The results suggest that muscle strengthening of the lower limbs did not improve performance in the 6-minute walk test in this population of postmenopausal women.

  14. Learning about Flood Risk: Comparing the Web-Based and Physical Flood-Walk Learning Environments

    Science.gov (United States)

    Chang Rundgren, Shu-Nu; Nyberg, Lars; Evers, Mariele; Alexandersson, Jan

    2015-01-01

    Numerous of sustainable development related challenges are emerging today, e.g. flooding problems. Our group has developed "the flood walk" project since 2010 to convey flood risk knowledge in an authentic context. Considering the limitation of time and space to educate people the flood risk knowledge, we tried to transform the physical…

  15. Mechanical energy assessment of adult with Down syndrome during walking with obstacle avoidance.

    Science.gov (United States)

    Salami, Firooz; Vimercati, Sara Laura; Rigoldi, Chiara; Taebi, Amirtaha; Albertini, Giorgio; Galli, Manuela

    2014-08-01

    The aim of this study is analyzing the differences between plane walking and stepping over an obstacle for two groups of healthy people and people with Down syndrome and then, evaluating the movement efficiency between the groups by comprising of their mechanical energy exchanges. 39 adults including two groups of 21 people with Down syndrome (age: 21.6 ± 7 years) and 18 healthy people (age: 25.1 ± 2.4 years) participated in this research. The test has been done in two conditions, first in plane walking and second in walking with an obstacle (10% of the subject's height). The gait data were acquired using quantitative movement analysis, composed of an optoelectronic system (Elite2002, BTS) with eight infrared cameras. Mechanical energy exchanges are computed by dedicated software and finally the data including spatiotemporal parameters, mechanical energy parameters and energy recovery of gait cycle are analyzed by statistical software to find significant differences. Regards to spatiotemporal parameters velocity and step length are lower in people with Down syndrome. Mechanical energy parameters particularly energy recovery does not change from healthy people to people with Down syndrome. However, there are some differences in inter-group through plane walking to obstacle avoidance and it means people with Down syndrome probably use their residual abilities in the most efficient way to achieve the main goal of an efficient energy recovery.

  16. Dynamic stability during level walking and obstacle crossing in persons with facioscapulohumeral muscular dystrophy

    NARCIS (Netherlands)

    Rijken, N.H.M.; Engelen, B.G.M. van; Geurts, A.C.H.; Weerdesteyn, V.G.

    2015-01-01

    Patients with FSHD suffer from progressive skeletal muscle weakness, which is associated with an elevated fall risk. To obtain insight into fall mechanisms in this patient group, we aimed to assess dynamic stability during level walking and obstacle crossing in patients at different disease stages.

  17. Crawling versus Walking Infants' Perception of Affordances for Locomotion over Sloping Surfaces.

    Science.gov (United States)

    Adolph, Karen E.; And Others

    1993-01-01

    Examined the behavior of 8.5-month-old crawling infants and 14-month-old walking toddlers in ascending and descending sloping walkways. Both groups overestimated their ability to ascend slopes. Toddlers hesitated most before descending 10 and 20 degree slopes, whereas infants hesitated most before descending 30 and 40 degree slopes. (MDM)

  18. BubbleType : Enabling Text Entry within a Walk-Up Tabletop Installation

    NARCIS (Netherlands)

    Hinrichs, Uta; Schmidt, Holly; Isenberg, Tobias; Hancock, Mark; Carpendale, Sheelagh

    2008-01-01

    We address the issue of enabling text entry for walk-up-and-use interactive tabletop displays located in public spaces. Public tabletop installations are characterized by a diverse target user group, multi-person interaction, and the need for high approachability and intuitiveness. We first define t

  19. Learning about Flood Risk: Comparing the Web-Based and Physical Flood-Walk Learning Environments

    Science.gov (United States)

    Chang Rundgren, Shu-Nu; Nyberg, Lars; Evers, Mariele; Alexandersson, Jan

    2015-01-01

    Numerous of sustainable development related challenges are emerging today, e.g. flooding problems. Our group has developed "the flood walk" project since 2010 to convey flood risk knowledge in an authentic context. Considering the limitation of time and space to educate people the flood risk knowledge, we tried to transform the physical…

  20. A botanical compound, Padma 28, increases walking distance in stable intermittent claudication

    DEFF Research Database (Denmark)

    Drabaek, H; Mehlsen, J; Himmelstrup, H

    1993-01-01

    and by measurements of the pain-free and the maximal walking distance on a treadmill. The ankle pressure index (ankle systolic pressure/arm systolic pressure) was calculated. The group randomized to active treatment received two tablets bid containing 340 mg of a dried herbal mixture composed according to an ancient...

  1. Illness, Injury, and Correlates of Aerobic Exercise and Walking: A Community Study.

    Science.gov (United States)

    Hofstetter, C. Richard; And Others

    1991-01-01

    A sample of Californians was surveyed to explore differences in aerobic exercise and walking behavior among healthy subjects and subjects with illness/injury serious enough to limit physical activity. Results indicate different patterns of determinants of exercise within various illness/injury groups. This implies interventions to increase…

  2. New Spiroplasma in parasitic Leptus mites and their Agathemera walking stick hosts from Argentina.

    Science.gov (United States)

    DiBlasi, Emily; Morse, Solon; Mayberry, Jason R; Avila, Luciano J; Morando, Mariana; Dittmar, Katharina

    2011-07-01

    Here we report the presence of Spiroplasma 16S rRNA in populations of two parasitic Leptus mites (Leptus sayi; Leptus lomani) and their Agathemera walking stick hosts. In walking sticks Spiroplasmas were detected in the gut, as well as muscle-tissues, but not in eggs. Throughout Argentina 15.4% of L. sayi populations and 14.3% of L. lomani populations surveyed screened positive for Spiroplasma. Phylogenetic analyses (ML, BCMC) place all sequences within the Ixodetis group. Most sequences form a well-supported sister subclade to the rest of Ixodetis. We briefly discuss the role of Leptus mites in the natural transmission of Spiroplasma.

  3. Effects of physical guidance on short-term learning of walking on a narrow beam

    OpenAIRE

    Domingo, Antoinette; Ferris, Daniel P.

    2009-01-01

    Physical guidance is often used in rehabilitation when teaching patients to re-learn movements. However, the effects of guidance on motor learning of complex skills, such as walking balance, are not clear. We tested four groups of healthy subjects that practiced walking on a narrow (1.27 cm) or wide (2.5 cm) treadmill-mounted balance beam, with or without physical guidance. Assistance was given by springs attached to a hip belt that applied restoring forces towards beam center. Subjects were ...

  4. Braking and propulsive impulses in individuals with patellofemoral pain syndrome when walking up and down stairs

    Directory of Open Access Journals (Sweden)

    Marcelo Camargo Saad

    2014-12-01

    Full Text Available Patellofemoral pain syndrome (PFPS is a prevalent clinical condition and it affects gait behavior. Braking and propulsive impulses are important biomechanical parameters obtained from ground reaction forces (GRF, which combine the amount of force applied over a period of time. The aim of this study was to evaluate these impulses while walking up and down stairs in healthy controls and PFPS individuals. The results did not reveal significant differences in braking and propulsive impulses between groups during these activities. Thus, the painful condition on a simple functional activity was insufficient to change the motor strategy to walking up or down the stairs.

  5. Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking

    Science.gov (United States)

    Pellegrini, Barbara; Peyré-Tartaruga, Leonardo Alexandre; Zoppirolli, Chiara; Bortolan, Lorenzo; Bacchi, Elisabetta; Figard-Fabre, Hélène; Schena, Federico

    2015-01-01

    Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill. PMID:26418339

  6. How might we increase physical activity through dog walking?: A comprehensive review of dog walking correlates

    OpenAIRE

    Westgarth, Carri; Christley, Robert M; Christian, Hayley E

    2014-01-01

    Background Physical inactivity and sedentary behaviour are major threats to population health. A considerable proportion of people own dogs, and there is good evidence that dog ownership is associated with higher levels of physical activity. However not all owners walk their dogs regularly. This paper comprehensively reviews the evidence for correlates of dog walking so that effective interventions may be designed to increase the physical activity of dog owners. Methods Published findings fro...

  7. Accumulating Brisk Walking for Fitness, Cardiovascular Risk, and Psychological Health.

    Science.gov (United States)

    Murphy, Marie; Nevill, Alan; Neville, Charlotte; Biddle, Stuart; Hardman, Adrianne

    2002-01-01

    Compared the effects of different patterns of regular brisk walking on fitness, cardiovascular disease risk factors, and psychological well-being in previously sedentary adults. Data on adults who completed either short-bout or long-bout walking programs found that three short bouts of brisk walking accumulated throughout the day were as effective…

  8. Modeling Framework and Software Tools for Walking Robots

    NARCIS (Netherlands)

    Duindam, Vincent; Stramigioli, Stefano; Groen, Frank

    2005-01-01

    In research on passive dynamic walking, the aim is to study and design robots that walk naturally, i.e., with little or no control effort. McGeer [1] and others (e.g. [2, 3]) have shown that, indeed, robots can walk down a shallow slope with no actuation, only powered by gravity. In this work, we de

  9. The Walking Classroom: Active Learning Is Just Steps Away!

    Science.gov (United States)

    Becker, Kelly Mancini

    2016-01-01

    Walking is a viable and valuable form of exercise for young children that has both physical and mental health benefits. There is much evidence showing that school-age children are not getting the recommended 60 minutes of daily exercise. A school-wide walking program can be a great way to encourage walking in and out of school, can be aligned with…

  10. Modeling Framework and Software Tools for Walking Robots

    NARCIS (Netherlands)

    Duindam, V.; Stramigioli, Stefano; Groen, F.N.J.

    2005-01-01

    In research on passive dynamic walking, the aim is to study and design robots that walk naturally, i.e., with little or no control effort. McGeer [1] and others (e.g. [2, 3]) have shown that, indeed, robots can walk down a shallow slope with no actuation, only powered by gravity. In this work, we

  11. Walking With’: A Rhythmanalysis of London’s East End

    Directory of Open Access Journals (Sweden)

    Yi Chen

    2013-12-01

    Full Text Available In this paper, I will be looking at the practice of walking through the lens of rhythmanalysis. The method is brought to attention by Lefebvre’s last book Rhythmanalysis (2004 in which he suggests a way of interrelating space and time; a phenomenological inquiry hinged on the concrete experience of lived life. My interest in the nuance of walking was initially evoked by the structural film Fergus Walking which was made by the film maker William Raban in 1978. I will explore the potential of using structural films in sensitising us to the temporal-spatial relationship of things. The main body of the paper centres around two themes: Firstly I address the primacy of movement as a mode of engaging with the world. It is through ‘muscular consciousness’ (Bachelard 1964: 11 that walking becomes a form of experiential knowing, feeling, connecting and protesting. Secondly, I examine the practices of walking in relation to the radical transformations of the Docklands’ landscape since the beginning of the 1980s. I propose that the contesting interests of different groups can be explored by analysing the rhythmic interactions of their activities. The transition and recomposition of an economy from locally based industrial activities to globalised financial services were manifested in the syncopation of regeneration rhythms to the living rhythms of the Docklands. The fast changing urban landscapes were negotiated through alternative ways of navigating the streets, hence engendering a different set of rhythms.

  12. Identification of the Causative Disease of Intermittent Claudication through Walking Motion Analysis: Feature Analysis and Differentiation

    Directory of Open Access Journals (Sweden)

    Tetsuyou Watanabe

    2014-01-01

    Full Text Available Intermittent claudication is a walking symptom. Patients with intermittent claudication experience lower limb pain after walking for a short time. However, rest relieves the pain and allows the patient to walk again. Unfortunately, this symptom predominantly arises from not 1 but 2 different diseases: LSS (lumber spinal canal stenosis and PAD (peripheral arterial disease. Patients with LSS can be subdivided by the affected vertebra into 2 main groups: L4 and L5. It is clinically very important to determine whether patients with intermittent claudication suffer from PAD, L4, or L5. This paper presents a novel SVM- (support vector machine- based methodology for such discrimination/differentiation using minimally required data, simple walking motion data in the sagittal plane. We constructed a simple walking measurement system that is easy to set up and calibrate and suitable for use by nonspecialists in small spaces. We analyzed the obtained gait patterns and derived input parameters for SVM that are also visually detectable and medically meaningful/consistent differentiation features. We present a differentiation methodology utilizing an SVM classifier. Leave-one-out cross-validation of differentiation/classification by this method yielded a total accuracy of 83%.

  13. Short-Term Motor Learning and Retention During Visually Guided Walking in Persons With Multiple Sclerosis.

    Science.gov (United States)

    McGowan, Kayla; Gunn, Shaila M; Vorobeychik, Galina; Marigold, Daniel S

    2017-07-01

    The ability to adapt, a form of short-term motor learning, and retain this adaptation, is essential for rehabilitation and for day-to-day living. Yet little research is available on this topic in persons with multiple sclerosis (PwMS), particularly in relation to complex walking tasks. To determine the ability of PwMS to learn and retain a novel relationship between visual input and motor output-or visuomotor map-during visually guided walking. Nineteen PwMS and 17 healthy controls performed a precision walking task while adapting to prism lenses that altered the normal visuomotor map on 1 day, and again after a 1-week delay. The task required individuals to walk and step onto 2 targets without stopping. To quantify motor performance, we determined foot placement error relative to the targets. PwMS with mild disability and healthy controls attenuated foot placement error over repeated trials when exposed to the novel mapping and demonstrated a similar rate and magnitude of adaptation in the first learning session. Both groups equally retained the adaptation 1 week later, reflected by reduced foot placement error and a faster rate of error reduction in that session. PwMS can learn and retain a novel visuomotor mapping during a precision-based walking task. This suggests that PwMS with mild disability have the capacity for short-term motor learning and retention, indicating that neural plasticity is preserved.

  14. On the pertinence to Physics of random walks induced by random dynamical systems: a survey

    Science.gov (United States)

    Petritis, Dimitri

    2016-08-01

    Let be an abstract space and a denumerable (finite or infinite) alphabet. Suppose that is a family of functions such that for all we have and a family of transformations . The pair ((Sa)a , (pa)a ) is termed an iterated function system with place dependent probabilities. Such systems can be thought as generalisations of random dynamical systems. As a matter of fact, suppose we start from a given ; we pick then randomly, with probability pa (x), the transformation Sa and evolve to Sa (x). We are interested in the behaviour of the system when the iteration continues indefinitely. Random walks of the above type are omnipresent in both classical and quantum Physics. To give a small sample of occurrences we mention: random walks on the affine group, random walks on Penrose lattices, random walks on partially directed lattices, evolution of density matrices induced by repeated quantum measurements, quantum channels, quantum random walks, etc. In this article, we review some basic properties of such systems and provide with a pathfinder in the extensive bibliography (both on mathematical and physical sides) where the main results have been originally published.

  15. EMG modulation in anticipation of a possible trip during walking in young and older adults.

    Science.gov (United States)

    Pijnappels, Mirjam; Bobbert, Maarten F; van Dieën, Jaap H

    2006-04-01

    This study investigated whether changes in lower limb muscle activity occurred in anticipation of a possible perturbation in 11 young (mean age 27 years) and 11 older (mean age 68 years) adults. Altered muscle activity could affect tripping responses and consequently the ecological validity of experimental results of studies on tripping. It was hypothesized that anticipatory muscle activity would be present immediately after a trip, and decrease after several subsequent unperturbed (forewarned) walking trials. Electromyograms of lower limb muscles were measured in 3 conditions: during normal walking, during forewarned walking immediately after a trip, and during forewarned walking several trials after a trip had occurred. Small but statistically significant differences in averaged muscle activity over a stride were found among conditions. Young adults showed slightly increased activity immediately after tripping (co-contraction) in hamstrings, quadriceps and tibialis anterior muscles. This increased activity diminished after several unperturbed trials, although it did not return to the baseline activity levels during normal walking. In older adults, an increased muscle activity among conditions was only discerned in tibialis anterior and soleus muscles. This suggested that older adults prefer to avoid contact with the obstacle over joint stiffening. Yet, for both age-groups, the increases in muscle activity were very small when compared to tripping responses reported in the literature. Therefore, anticipatory effects are not expected to jeopardize the validity of experiments in which subjects are perturbed more than once.

  16. A Passive Dynamic Walking Model Based on Knee-Bend Behaviour: Stability and Adaptability for Walking Down Steep Slopes

    Directory of Open Access Journals (Sweden)

    Kang An

    2013-10-01

    Full Text Available This paper presents a passive dynamic walking model based on knee-bend behaviour, which is inspired by the way human beings walk. The length and mass parameters of human beings are used in the walking model. The knee-bend mechanism of the stance leg is designed in the phase between knee-strike and heel- strike. q* which is the angular difference of the stance leg between the two events, knee-strike and knee-bend, is adjusted in order to find a stable walking motion. The results show that the stable periodic walking motion on a slope of r <0.4 can be found by adjusting q*. Furthermore, with a particular q* in the range of 0.12walk down more steps before falling down on an arbitrary slope. The walking motion is more stable and adaptable than the conventional walking motion, especially for steep slopes.

  17. A Passive Dynamic Walking Model Based on Knee-Bend Behaviour: Stability and Adaptability for Walking down Steep Slopes

    Directory of Open Access Journals (Sweden)

    Kang An

    2013-10-01

    Full Text Available This paper presents a passive dynamic walking model based on knee-bend behaviour, which is inspired by the way human beings walk. The length and mass parameters of human beings are used in the walking model. The knee-bend mechanism of the stance leg is designed in the phase between knee-strike and heel-strike. q* which is the angular difference of the stance leg between the two events, knee-strike and knee-bend, is adjusted in order to find a stable walking motion. The results show that the stable periodic walking motion on a slope of r <0.4 can be found by adjusting q*. Furthermore, with a particular q* in the range of 0.12walk down more steps before falling down on an arbitrary slope. The walking motion is more stable and adaptable than the conventional walking motion, especially for steep slopes.

  18. Using Virtual Reality to Improve Walking Post-Stroke: Translation to Individuals with Diabetes

    Science.gov (United States)

    Deutsch, Judith E

    2011-01-01

    Use of virtual reality (VR) technology to improve walking for people post-stroke has been studied for its clinical application since 2004. The hardware and software used to create these systems has varied but has predominantly been constituted by projected environments with users walking on treadmills. Transfer of training from the virtual environment to real-world walking has modest but positive research support. Translation of the research findings to clinical practice has been hampered by commercial availability and costs of the VR systems. Suggestions for how the work for individuals post-stroke might be applied and adapted for individuals with diabetes and other impaired ambulatory conditions include involvement of the target user groups (both practitioners and clients) early in the design and integration of activity and education into the systems. PMID:21527098

  19. Enumeration of closed random walks in the square lattice according to their areas

    CERN Document Server

    Mohammad-Noori, Morteza

    2010-01-01

    We study the area distribution of closed walks of length $n$, beginning and ending at the origin. The concept of area of a walk in the square lattice is generalized and the usefulness of the new concept is demonstrated through a simple argument. It is concluded that the number of walks of length $n$ and area $s$ equals to the coefficient of $z^s$ in the expression $(x+x^{-1}+y+y^{-1})^n$, where the calculations are performed in a special group ring $R[x,y,z]$. A polynomial time algorithm for calculating these values, is then concluded. Finally, the provided algorithm and the results of implementation are compared with previous works.

  20. Physiological Responses Associated with Nordic-Walking Training in Systolic Hypertensive Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Latosik Ewelina

    2014-12-01

    Full Text Available Loss of physical strength and hypertension are among the most pronounced detrimental factors accompanying aging. The aim of this study was to evaluate the influence of a supervised 8-week Nordic-walking training program on systolic blood pressure in systolic-hypertensive postmenopausal women. This study was a randomized control trial on a sample of 24 subjects who did not take any hypertension medications. There was a statistically significant decrease in systolic blood pressure and an increase in lower and upper-body strength in the group following Nordic-walking training. There was a decrease in serum levels of total cholesterol, triglycerides, and low-density cholesterol. The obtained results indicate that an 8-week Nordic-walking program may be efficiently employed for counteracting systolic hypertension through a direct abatement of systolic blood pressure and an increase of maximal aerobic capacity.

  1. Evolution of Biped Walking Using Neural Oscillators Controller and Harmony Search Algorithm Optimizer

    CERN Document Server

    Yazdi, Ebrahim

    2010-01-01

    In this paper, a simple Neural controller has been used to achieve stable walking in a NAO biped robot, with 22 degrees of freedom that implemented in a virtual physics-based simulation environment of Robocup soccer simulation environment. The algorithm uses a Matsuoka base neural oscillator to generate control signal for the biped robot. To find the best angular trajectory and optimize network parameters, a new population-based search algorithm, called the Harmony Search (HS) algorithm, has been used. The algorithm conceptualized a group of musicians together trying to search for better state of harmony. Simulation results demonstrate that the modification of the step period and the walking motion due to the sensory feedback signals improves the stability of the walking motion.

  2. Using virtual reality to improve walking post-stroke: translation to individuals with diabetes.

    Science.gov (United States)

    Deutsch, Judith E

    2011-03-01

    Use of virtual reality (VR) technology to improve walking for people post-stroke has been studied for its clinical application since 2004. The hardware and software used to create these systems has varied but has predominantly been constituted by projected environments with users walking on treadmills. Transfer of training from the virtual environment to real-world walking has modest but positive research support. Translation of the research findings to clinical practice has been hampered by commercial availability and costs of the VR systems. Suggestions for how the work for individuals post-stroke might be applied and adapted for individuals with diabetes and other impaired ambulatory conditions include involvement of the target user groups (both practitioners and clients) early in the design and integration of activity and education into the systems.

  3. Energy cost of balance control during walking decreases with external stabilizer stiffness independent of walking speed.

    Science.gov (United States)

    Ijmker, Trienke; Houdijk, Han; Lamoth, Claudine J C; Beek, Peter J; van der Woude, Lucas H V

    2013-09-03

    Human walking requires active neuromuscular control to ensure stability in the lateral direction, which inflicts a certain metabolic load. The magnitude of this metabolic load has previously been investigated by means of passive external lateral stabilization via spring-like cords. In the present study, we applied this method to test two hypotheses: (1) the effect of external stabilization on energy cost depends on the stiffness of the stabilizing springs, and (2) the energy cost for balance control, and consequently the effect of external stabilization on energy cost, depends on walking speed. Fourteen healthy young adults walked on a motor driven treadmill without stabilization and with stabilization with four different spring stiffnesses (between 760 and 1820 Nm(-1)) at three walking speeds (70%, 100%, and 130% of preferred speed). Energy cost was calculated from breath-by-breath oxygen consumption. Gait parameters (mean and variability of step width and stride length, and variability of trunk accelerations) were calculated from kinematic data. On average external stabilization led to a decrease in energy cost of 6% (pwalking speed (p=0.111). These results show that active lateral stabilization during walking involves an energetic cost, which is independent of walking speed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Comparison of elliptical training, stationary cycling, treadmill walking and overground walking. Electromyographic patterns.

    Science.gov (United States)

    Prosser, Laura A; Stanley, Christopher J; Norman, Tracy L; Park, Hyung S; Damiano, Diane L

    2011-02-01

    The most common functional motor goal of lower extremity rehabilitation is to improve walking ability. For reasons of feasibility, safety or intensity, devices are frequently used to facilitate or augment gait training. The objective of this study was to compare the muscle activity patterns of the rectus femoris and semitendinosus muscles during four conditions: overground walking, treadmill walking, stationary cycling, and elliptical training. Ten healthy adults (six male, four female; mean age 22.7±2.9 years, range 20-29) participated and surface electromyographic data were recorded. Linear envelope curves were generated and time normalized from 0 to 100% cycle. The mean plus three standard deviations from a static trial was used as the threshold for muscle activity. Repeated measures analysis of variance procedures were used to detect differences between conditions. Elliptical training demonstrated greater rectus femoris activity and greater rectus femoris/semitendinosus coactivation than all other conditions. Consistent with previous work, treadmill walking demonstrated greater rectus femoris activity than overground walking. Minimal differences in semitendinosus activation were observed between conditions, limited to lower peak activity during cycling compared to treadmill walking. These results provide normative values for rectus femoris and semitendinosus activation for different locomotor training methods and may assist in selecting the most appropriate training device for specific patients. Clinicians and researchers should also consider the kinematic and kinetic differences between tasks, which cannot necessarily be inferred from muscle activation patterns.

  5. Alterations in walking knee joint stiffness in individuals with knee osteoarthritis and self-reported knee instability

    Science.gov (United States)

    Gustafson, Jonathan A.; Gorman, Shannon; Fitzgerald, G. Kelley; Farrokhi, Shawn

    2017-01-01

    Increased walking knee joint stiffness has been reported in patients with knee osteoarthritis (OA) as a compensatory strategy to improve knee joint stability. However, presence of episodic self-reported knee instability in a large subgroup of patients with knee OA may be a sign of inadequate walking knee joint stiffness. The objective of this work was to evaluate the differences in walking knee joint stiffness in patients with knee OA with and without self-reported instability and examine the relationship between walking knee joint stiffness with quadriceps strength, knee joint laxity, and varus knee malalignment. Overground biomechanical data at a self-selected gait velocity was collected for 35 individuals with knee OA without self-reported instability (stable group) and 17 individuals with knee OA and episodic self-reported instability (unstable group). Knee joint stiffness was calculated during the weight-acceptance phase of gait as the change in the external knee joint moment divided by the change in the knee flexion angle. The unstable group walked with lower knee joint stiffness (p=0.01), mainly due to smaller heel-contact knee flexion angles (pknee flexion excursions (pknee stable counterparts. No significant relationships were observed between walking knee joint stiffness and quadriceps strength, knee joint laxity or varus knee malalignment. Reduced walking knee joint stiffness appears to be associated with episodic knee instability and independent of quadriceps muscle weakness, knee joint laxity or varus malalignment. Further investigations of the temporal relationship between self-reported knee joint instability and walking knee joint stiffness are warranted. PMID:26481256

  6. Alterations in walking knee joint stiffness in individuals with knee osteoarthritis and self-reported knee instability.

    Science.gov (United States)

    Gustafson, Jonathan A; Gorman, Shannon; Fitzgerald, G Kelley; Farrokhi, Shawn

    2016-01-01

    Increased walking knee joint stiffness has been reported in patients with knee osteoarthritis (OA) as a compensatory strategy to improve knee joint stability. However, presence of episodic self-reported knee instability in a large subgroup of patients with knee OA may be a sign of inadequate walking knee joint stiffness. The objective of this work was to evaluate the differences in walking knee joint stiffness in patients with knee OA with and without self-reported instability and examine the relationship between walking knee joint stiffness with quadriceps strength, knee joint laxity, and varus knee malalignment. Overground biomechanical data at a self-selected gait velocity was collected for 35 individuals with knee OA without self-reported instability (stable group) and 17 individuals with knee OA and episodic self-reported instability (unstable group). Knee joint stiffness was calculated during the weight-acceptance phase of gait as the change in the external knee joint moment divided by the change in the knee flexion angle. The unstable group walked with lower knee joint stiffness (p=0.01), mainly due to smaller heel-contact knee flexion angles (pknee flexion excursions (pknee stable counterparts. No significant relationships were observed between walking knee joint stiffness and quadriceps strength, knee joint laxity or varus knee malalignment. Reduced walking knee joint stiffness appears to be associated with episodic knee instability and independent of quadriceps muscle weakness, knee joint laxity or varus malalignment. Further investigations of the temporal relationship between self-reported knee joint instability and walking knee joint stiffness are warranted.

  7. Walking behaviours from the 1965–2003 American Heritage Time Use Study (AHTUS

    Directory of Open Access Journals (Sweden)

    Merom Dafna

    2007-09-01

    Full Text Available Abstract Background The American Heritage Time Use Study (AHTUS represents a harmonised historical data file of time use by adults, amalgamating surveys collected in 1965–66, 1975–76, 1985, 1992–94, and 2003. The objectives of time-use studies have ranged from evaluating household and other unpaid production of goods and services, to monitoring of media use, to comparing lifestyles of more and less privileged social groups, or to tracking broad shifts in social behaviour. The purpose of this paper is to describe the process and utility of identifying and compiling data from the AHTUS to describe a range of walking behaviours collected using time-use survey methods over almost 40 years in the USA. Methods This is a secondary data analysis of an existing amalgamated data set. Noting source survey-specific limitations in comparability of design, we determined age-standardized participation (and associated durations in any walking, walking for exercise, walking for transport, walking the dog, sports/exercise (excluding walking, and all physical activity for those survey years for which sufficient relevant data details were available. Results Data processing revealed inconsistencies in instrument administration, coding various types of walking and in prompting other sport/exercise across surveys. Thus for the entire period, application of inferential statistics to determine trend for a range of walking behaviours could not be done with confidence. Focusing on the two most comparable survey years, 1985 and 2003, it appears that walking for exercise in America has increased in popularity on any given day (from 2.9 to 5.4% of adults and accumulated duration amongst those who walk for exercise (from 30 to 45 mins/day. Dog walking has decreased in popularity over the same time period (from 9.4 to 2.6%. Associated duration amongst dog walkers was stable at 30 mins/day. Conclusion The noted and sometimes substantial differences in methods between the

  8. Influence of the swing ankle angle on walking stability for a passive dynamic walking robot with flat feet

    Directory of Open Access Journals (Sweden)

    Xizhe Zang

    2016-03-01

    Full Text Available To achieve high walking stability for a passive dynamic walking robot is not easy. In this article, we aim to investigate whether the walking performance for a passive dynamic walking robot can be improved by just simply changing the swing ankle angle before impact. To validate this idea, a passive bipedal walking model with two straight legs, two flat feet, a hip joint, and two ankle joints was built in this study. The walking dynamics that contains double stance phase was derived. By numerical simulation of the walking in MATLAB, we found that the walking performance can be adjusted effectively by only simply changing the swing ankle angle before impact. A bigger swing ankle angle in a reasonable range will lead to a higher walking stability and a lower initial walking speed of the next step. A bigger swing ankle angle before impact leads to a bigger amount of energy lost during impact for the quasi-passive dynamic walking robot which will influence the walking stability of the next step.

  9. 76 FR 33631 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

    Science.gov (United States)

    2011-06-09

    ... regulatory text should read as set forth below: PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL... measure the energy consumption of the components that make up the envelope of a walk-in cooler or walk-in... ``external conditions'' of the shared surface(s) must reflect the internal conditions of the adjacent walk-in...

  10. A comparison of at-home walking and 10-meter walking test parameters of individuals with post-stroke hemiparesis.

    Science.gov (United States)

    Nagano, Katsuhito; Hori, Hideaki; Muramatsu, Ken

    2015-02-01

    [Purpose] The purpose of this study was to clarify the difference in gait parameters of at-home walking and the 10-meter walking test results of individuals with hemiparesis. [Subjects] A total of 14 hemiparetic stroke recovery patients participated in this study. Inclusion criteria were: living at home, the ability to walk independently, and demonstrated low extremity on recovery stages III-V on the Brunnstrom Approach. The average age of the subjects was 66 years. [Methods] We used video surveillance and the inked footprint technique to record usual walking speed and maximum speed patterns both in subjects' homes and during the 10-meter walking test. From these methods, walking speed, stride length, and step rate were calculated. [Results] While both usual and maximum walking speeds of the 10-meter walking test correlated with stride length and step rate, at-home walking speeds only significantly correlated with stride length. [Conclusion] Walking patterns of the 10-meter walking test are quantifiably distinct from those demonstrated in patients' homes, and this difference is mainly characterized by stride length. In order to enhance in-home walking ability, exercises that improve length of stride rather than step rate should be recommended.

  11. Walking in the neighbourhood: Performing social citizenship in dementia.

    Science.gov (United States)

    Phinney, Alison; Kelson, Elizabeth; Baumbusch, Jennifer; O'Connor, Deborah; Purves, Barbara

    2016-05-01

    The proliferation of community-based activity programs for people with dementia suggests an appetite for new approaches to support quality of life and well-being for this population. Such groups also have potential to promote social citizenship, although this remains poorly understood. This article presents findings from a subset of data from an ethnographic study of a community-based program for people with young onset dementia; it focuses on Paul's Club and the experiences of 12-15 members who are physically healthy, with moderate to moderately severe dementia. Analysis suggests how aspects of social citizenship are constructed and revealed through the Club's everyday practice of walking in the neighbourhood. Three major themes emerged: Keeping the focus off dementia; Creating a place of belonging; and Claiming a place in the community How the group balances consideration of members' vulnerability and agency is discussed, and the article concludes with implications for future practice and research initiatives.

  12. Dogs, physical activity, and walking (dogs PAW): acceptability and feasibility of a pilot physical activity intervention.

    Science.gov (United States)

    Richards, Elizabeth A; Ogata, Niwako; Ting, Jeffrey

    2015-05-01

    The aims of this study were to describe the development of and investigate the feasibility and acceptability of a pilot randomized controlled physical activity intervention based on social cognitive theory that used a dog walking strategy. Participants (n = 49) were randomized into an intervention or control group. Overall, participants were middle-aged (M = 45.7 ± 13.4 years), Caucasian, and on average considered obese with a mean body mass index of 30.0 ± 5.5. Descriptive statistics were used to summarize participant characteristics and analyze the feasibility and acceptability data. Regression models were used to (a) examine significant differences between intervention and control groups across time (baseline to post-intervention) and (b) examine if changes in theoretical constructs from baseline to post-intervention resulted in changes in dog walking in both the intervention and control group. Participants agreed that the intervention e-mails were easy to read and understand (M = 4.3 ± 0.7). Participants reported that the frequency of e-mails was adequate (M = 4.3 ± 0.8), but there was lower agreement that the e-mails encouraged an increase in dog walking (M = 3.6 ± 1.2). Post-intervention, the control group increased weekly dog walking to 19.4 ± 4.9 minutes, whereas the intervention group increased it to 79.3 ± 11.2 minutes. Preliminary results suggest that this pilot intervention is an acceptable and feasible strategy for promoting dog walking among dog owners. © 2014 Society for Public Health Education.

  13. Prediction of Independent Walking Ability for Severely Hemiplegic Stroke Patients at Discharge from a Rehabilitation Hospital.

    Science.gov (United States)

    Hirano, Yoshitake; Hayashi, Takeshi; Nitta, Osamu; Takahashi, Hidetoshi; Nishio, Daisuke; Minakawa, Tomoya; Kigawa, Hiroshi

    2016-08-01

    It is important to predict walking ability for stroke patients, because rehabilitation programs are planned on such predictions. We therefore examined predictive factors that are available before discharge from a rehabilitation hospital. Seventy-two consecutive patients with a first attack of stroke with severe hemiplegia were included in this study. We retrospectively evaluated background factors (age, gender, time from stroke onset, paresis side, and stroke type). Other neurological and physical parameters were collected by means of the modified National Institutes of Health Stroke Scale, the Mini-Mental State Examination, the Trunk Control Test (TCT), and the knee extension strength/body weight ratio on the unaffected side (KES/BW-US) at the time of admission. We divided the patients into 2 groups, the independent group (n = 49) and the dependent group (n = 23), on the basis of the Barthel Index of mobility at the time of discharge. We then compared the 2 groups with respect to the aforementioned parameters. We also performed stepwise discriminant analyses to ascertain which parameters are the best predictors of walking ability at the time of discharge. Age, TCT score, and the KES/BW-US ratio were significantly different between the groups. Discriminant analysis revealed that younger age and a higher KES/BW-US ratio were significantly associated with walking ability at discharge, which could be precisely predicted using the following formula: Y = .093 × (age) - 4.316 × (KES/BW-US) - 4.984. At the time of admission, age and the KES/BW-US ratio permit the prediction of independent walking ability at the time of discharge. Our formula predicts walking ability with an accuracy of more than 91%. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  14. Effects of shoe type on lower extremity muscle activity during treadmill walking.

    Science.gov (United States)

    Kim, Mi-Kyoung; Kim, Young-Hwan; Yoo, Kyung-Tae

    2015-12-01

    [Purpose] The purpose of this study was to analyze the effects of different shoe types on lower extremity muscle activity in healthy young women by using electromyography. [Subjects and Methods] Fifteen healthy young women in their 20s were included in this single-group repeated measures study. The subjects were divided into three groups: Converse sneakers, rain boots, and combat boots. The subjects walked on a treadmill at 4 km/h for 30 min, during which six muscles were examined using electromyography: the rectus femoris, vastus medialis, semimembranosus, tibialis anterior, peroneus longus, and medial head of the gastrocnemius. Between switching shoe types, a 24-h rest period was instated to prevent the fatigue effect from treadmill walking. [Results] One-way analysis of variance used to compare electromyography results among the three groups showed that the main effect of group differed significantly for the vastus medialis. Vastus medialis activity was higher in the rain boots group than the Converse sneakers group, and it was higher in the combat boots group than rain boots group. [Conclusion] Shoe type affects lower extremity muscle activity. Our findings may help individuals choose the ideal shoes for daily walking.

  15. Modulation of walking speed by changing optic flow in persons with stroke

    Directory of Open Access Journals (Sweden)

    Lamontagne Anouk

    2007-06-01

    Full Text Available Abstract Background Walking speed, which is often reduced after stroke, can be influenced by the perception of optic flow (OF speed. The present study aims to: 1 compare the modulation of walking speed in response to OF speed changes between persons with stroke and healthy controls and 2 investigate whether virtual environments (VE manipulating OF speed can be used to promote volitional changes in walking speed post stroke. Methods Twelve persons with stroke and 12 healthy individuals walked on a self-paced treadmill while viewing a virtual corridor in a helmet-mounted display. Two experiments were carried out on the same day. In experiment 1, the speed of an expanding OF was varied sinusoidally at 0.017 Hz (sine duration = 60 s, from 0 to 2 times the subject's comfortable walking speed, for a total duration of 5 minutes. In experiment 2, subjects were exposed to expanding OFs at discrete speeds that ranged from 0.25 to 2 times their comfortable speed. Each test trial was paired with a control trial performed at comfortable speed with matching OF. For each of the test trials, subjects were instructed to walk the distance within the same time as during the immediately preceding control trial. VEs were controlled by the CAREN-2 system (Motek. Instantaneous changes in gait speed (experiment 1 and the ratio of speed changes in the test trial over the control trial (experiment 2 were contrasted between the two groups of subjects. Results When OF speed was changing continuously (experiment 1, an out-of-phase modulation was observed in the gait speed of healthy subjects, such that slower OFs induced faster walking speeds, and vice versa. Persons with stroke displayed weaker (p 0.05, T-test. Conclusion Stroke affects the modulation of gait speed in response to changes in the perception of movement through different OF speeds. Nevertheless, the preservation of even a modest modulation enabled the persons with stroke to increase walking speed when

  16. Validating the feedback control of intersegmental coordination by fluctuation analysis of disturbed walking.

    Science.gov (United States)

    Funato, Tetsuro; Aoi, Shinya; Tomita, Nozomi; Tsuchiya, Kazuo

    2015-05-01

    A walking motion is established by feedforward control for rhythmic locomotion and feedback control for adapting to environmental variations. To identify the control variables that underlie feedback control, uncontrolled manifold (UCM) analysis has been proposed and adopted for analyzing various movements. UCM analysis searches the controlled variables by comparing the fluctuation size of segmental groups related and unrelated to the movement of candidate variables, based on the assumption that a small fluctuation size indicates a relationship with the feedback control. The present study was based on UCM analysis and evaluated fluctuation size to determine the control mechanism for walking. While walking, the subjects were subjected to floor disturbances at two different frequencies, and the fluctuation sizes of the segmental groups related to characteristic variables were calculated and compared. The characteristic variables evaluated were the motion of the center of mass, limb axis, and head, and the intersegmental coordination of segmental groups with simultaneous coupled movements. Results showed that the fluctuations in intersegmental coordination were almost equally small for any segment, while fluctuations in the other variables were large in certain segments. Moreover, a comparison of the fluctuation sizes among the evaluated variables showed that the fluctuation size for intersegmental coordination was the smallest. These results indicate a possible relationship between intersegmental coordination and the control of walking.

  17. Concave Majorants of Random Walks and Related Poisson Processes

    CERN Document Server

    Abramson, Josh

    2010-01-01

    We offer a unified approach to the theory of concave majorants of random walks by providing a path transformation for a walk of finite length that leaves the law of the walk unchanged whilst providing complete information about the concave majorant. This leads to a description of a walk of random geometric length as a Poisson point process of excursions away from its concave majorant, which is then used to find a complete description of the concave majorant for a walk of infinite length. In the case where subsets of increments may have the same arithmetic mean, we investigate three nested compositions that naturally arise from our construction of the concave majorant.

  18. Random walk search in unstructured P2P

    Institute of Scientific and Technical Information of China (English)

    Jia Zhaoqing; You Jinyuan; Rao Ruonan; Li Minglu

    2006-01-01

    Unstructured P2P has power-law link distribution, and the random walk in power-law networks is analyzed. The analysis results show that the probability that a random walker walks through the high degree nodes is high in the power-law network, and the information on the high degree nodes can be easily found through random walk. Random walk spread and random walk search method (RWSS) is proposed based on the analysis result. Simulation results show that RWSS achieves high success rates at low cost and is robust to high degree node failure.

  19. About the walking machine motion stability

    Directory of Open Access Journals (Sweden)

    V. V. Lapshin

    2014-01-01

    Full Text Available The use of legs as propulsive devices of the machine will increase its capability to cross rough and deformable terrain as compared with wheeled and trucked machines. Today it is already possible to speak about design of statically stable walking robots to be used in the certain areas of application. The most promising areas of their application are exploration and emergency-rescue operations in extremely complicated situations (e.g. in the zone of destruction after earthquakes, technogenic catastrophe, etc..In such dangerous situations there is a possibility for the walking machine to be overturned either because of loosing a support to one or several legs or due to significant displacement of the leg support points, which are caused by deformation or destruction of the terrain in the points of the legs support. Therefore, it is necessary to design motion control algorithms that enable teaching the motion control system of a walking robot: How to decrease the possibility of the robot overturning? How to stop the robot as quickly as possible keeping its static stability? What must be done if static stability is lost? Note that the loss of static stability does not inevitably result in the robot falling down. How to fall down better (with minimal robot destruction in inevitable case?This work investigates the first abovementioned problems, i.e. preventing a walking machine from overturning in dangerous situations. For this purpose it suggests to use a special cautious (safe gait, which allows the machine to remain statically stable if it suddenly looses support to its any leg. The natural price for the increased safety to prevent from overturning is the reduced capabilities of robot kinematics and, as a consequence, its capability to cross rough terrain. It is also suggested to reconsider the general definition of a walking machine static stability margin in order to obtain an adequate estimation of the robot overturning possibility

  20. Comparison of the effects of Korean mindfulness-based stress reduction, walking, and patient education in diabetes mellitus.

    Science.gov (United States)

    Jung, Hee Young; Lee, Haejung; Park, Jina

    2015-12-01

    The purpose of this study was to compare the effects of Korean mindfulness-based stress reduction (K-MBSR), walking, and patient education regarding diabetes mellitus (DM) on stress response, glycemic control, and vascular inflammation in patients with diabetes mellitus. A cluster randomized trial including 56 adults with diabetes mellitus (K-MBSR group = 21, walking group = 18, patient education group = 17) was conducted between 13 July and 14 September 2012. The questionnaire included the Diabetes Distress Scale and Perceived Stress Response Inventory. Fasting blood samples were used to measure levels of cortisol, blood glucose, plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (t-PA). There were no statistically significant differences between the effects of K-MBSR, walking, and patient education on stress, glycemic control, or vascular inflammation. However, in the K-MBSR and walking groups, significant reductions in the levels of serum cortisol and PAI-1 were observed. A significant reduction in psychological responses to stress was observed in the walking and patient education groups. Longitudinal studies could provide better insight into the impact of K-MBSR, walking, and patient education on health outcomes in adults with diabetes mellitus. © 2015 Wiley Publishing Asia Pty Ltd.