Walking In Place Research Articles

Interventions for varicose veins and leg oedema in pregnancy.

Interventions for varicose veins and leg oedema in pregnancy.

Compliance control for stabilizing the humanoid on the changing slope based on terrain inclination estimation

This paper presents a stabilization framework integrated with the estimation of the terrain inclination to balance a humanoid on the changing slope as an extension to our previous study. In this paper, the estimation of the terrain inclination is improved for walking in place on an inclination-varying slope. A passivity based admittance control utilizes the force/torque sensing in feet to actively regulate the impedance at the center of mass to stabilize the robot. The logic-based inclination estimation algorithm uses the feet to probe the terrain and deals with the under-actuation. The equilibrium set-point in the admittance control is regulated based on the detected inclination. The effectiveness of the control framework is validated on the humanoid robot COMAN and demonstrated by estimating the terrain inclination, coping with the under-actuation phase, adapting to the slope with changing inclination during both standing and walking. Experimental data are analyzed and discussed, and the future work is suggested.

Older adults prioritize postural stability in the anterior–posterior direction to regain balance following volitional lateral step

BackgroundPostural control in the medial–lateral (ML) direction is of particular interest regarding the assessment of changes in postural control, as it is highly related to the risk of falling. ObjectiveTo determine the postural strategies used to regain balance following a voluntary lateral step and compare these strategies between young and older adults. MethodsSixteen older adults (60–90 years) and 14 young adults (20–40 years) were asked to stand quietly for 30s, walk in place and then take a lateral step and stand quietly (30s). Balance Post was divided into 10s intervals. Center of pressure displacement (CoP) and velocity (VCoP) in the anterio-posterior (AP) and ML directions were analyzed. ResultsIn both groups, CoP and VCoP in AP and ML increased in Post1 compared to Pre (P<0.001). Dissimilar to young adults, VCoP-Post2, Post3 ML were larger than Pre (P=0.01) in older adults. Age correlated with all VCoP (Pre and Post) in both ML (P<0.05) and AP directions (P<0.01). ConclusionsDissimilar to young adults, older adults use different postural strategies in ML and AP directions and prioritized postural stability in the AP direction to recover balance after completing a lateral step. In the ML direction, older adults took up to 30s to regain balance. Considering that age was related to larger CoP displacement and velocity, the AP strategy to recover postural balance following a lateral step could become less efficient as older adults age and therefore increasing the risk of falls.

Wireless Communication by an Autonomous Self-Powered Cyborg Insect

A trehalose/oxygen biofuel cell was implanted in Blaberus discoidalis to convert chemical energy stored within the insect hemolymph into electrical energy which was then used to power a custom-designed oscillator mounted on the back of the insect, capable of producing signals in the audible range. The ability of this cyborg to generate and transmit signals wirelessly was demonstrated by placing an external receiver up to a few centimeters away from the insect while it was tethered to a device that enabled it to walk in place on top of a light weight, air-suspended solid sphere. Wireless communication could also be established between the transmitter powered by the same type of biofuel cell implanted in the moth Manduca sexta and the receiver, while the live insect was being restrained with wax in a Petri dish. Possible means of reducing the weight and size of the transmitter so as to allow the moth to carry it in flight are discussed.

Evidence against an ecological explanation of the jitter advantage for vection.

Visual-vestibular conflicts have been traditionally used to explain both perceptions of self-motion and experiences of motion sickness. However, sensory conflict theories have been challenged by findings that adding simulated viewpoint jitter to inducing displays enhances (rather than reduces or destroys) visual illusions of self-motion experienced by stationary observers. One possible explanation of this jitter advantage for vection is that jittering optic flows are more ecological than smooth displays. Despite the intuitive appeal of this idea, it has proven difficult to test. Here we compared subjective experiences generated by jittering and smooth radial flows when observers were exposed to either visual-only or multisensory self-motion stimulations. The display jitter (if present) was generated in real-time by updating the virtual computer-graphics camera position to match the observer’s tracked head motions when treadmill walking or walking in place, or was a playback of these head motions when standing still. As expected, the (more naturalistic) treadmill walking and the (less naturalistic) walking in place were found to generate very different physical head jitters. However, contrary to the ecological account of the phenomenon, playbacks of treadmill walking and walking in place display jitter both enhanced visually induced illusions of self-motion to a similar degree (compared to smooth displays).

Interactive footstep sounds modulate the perceptual-motor aftereffect of treadmill walking.

In this study, we investigated the role of interactive auditory feedback in modulating the inadvertent forward drift experienced while attempting to walk in place with closed eyes following a few minutes of treadmill walking. Simulations of footstep sounds upon surface materials such as concrete and snow were provided by means of a system composed of headphones and shoes augmented with sensors. In a control condition, participants could hear their actual footstep sounds. Results showed an overall enhancement of the forward drift after treadmill walking independent of the sound perceived, while the strength of the aftereffect, measured as the proportional increase (posttest/pretest) in forward drift, was higher under the influence of snow compared to both concrete and actual sound. In addition, a higher knee angle flexion was found during the snow sound condition both before and after treadmill walking. Behavioral results confirmed those of a perceptual questionnaire, which showed that the snow sound was effective in producing strong pseudo-haptic illusions. Our results provide evidence that the walking in place aftereffect results from a recalibration of haptic, visuo-motor but also sound-motor control systems. Self-motion perception is multimodal.

Assisting obese students with intellectual disabilities to actively perform the activity of walking in place using a dance pad to control their preferred environmental stimulation

This study used a standard dance pad with a newly developed foot-pressing position detection program (FPPDP) software program. FPPDP is a new software program which was used to turn a standard dance pad into a foot-pressing position detector to evaluate whether two people with intellectual disabilities would be able to actively perform the activity of walking in place in order to control their preferred environmental stimulation. This study was performed according to a multiple baseline design across participants. The data showed that both participants were more willing to perform the activity of walking activity to activate the environmental stimulation during the intervention phases than in the baseline phase, and retained this effective performance in the maintenance phase. The practical and developmental implications of the findings are discussed.

Data Compression for Dynamic Image Sequences

The temporal modes from Principle Component Analysis (PCA) are an effective tool for compressing pre-segmented information. This paper estimates a dynamic model for these temporal modes based on a sequential set of pre-segmented data. In particular, we analyze the gait of a man walking in place on a tread mill. We then apply it to a system where an occasional frame comes through covered with noise, and in such a situation we use a Kalman-Filter to identify the temporal modes, and it provides estimates with smoother, more realistic, dynamics than those of non-dynamic estimates such as least-squares. Afterward, we break our code by showing that the estimates and models are only as good as the data set with which they were trained.

Establishing the Range of Perceptually Natural Visual Walking Speeds for Virtual Walking-In-Place Locomotion

Walking-In-Place (WIP) techniques make it possible to facilitate relatively natural locomotion within immersive virtual environments that are larger than the physical interaction space. However, in order to facilitate natural walking experiences one needs to know how to map steps in place 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 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, 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-of-views (FOVs) and two types of movement, walking on a treadmill and WIP locomotion. The results revealed significant main effects of both movement type and field of view, but no significant interaction between the two variables. Particularly, they suggest that the size of the display FOV is inversely proportional to the degree of underestimation of the virtual speeds for both treadmill-mediated virtual walking and WIP locomotion. Combined, the results constitute a first attempt at establishing a set of guidelines specifying what virtual walking speeds WIP gestures should produce in order to facilitate a natural walking experience.

THE DEVELOPMENT OF ENGLISH LANGUAGE TEACHING (ELT) COMPETENCY-BASED SYLLABUS IN SENIOR HIGH SCHOOL

Although competency has long been the major concern in ELT either in the EFL or ESL contexts, the rise of competency-based syllabus launched by the Ministry of National Education (2006) brought about significant issue among the English teachers in the country. One of the crucial issues is that how to transfer the concepts of competences into the syllabus design. Since a syllabus does not only contain a list of subject content, but also how curriculum planners (teachers) reflect their understanding and belief about nature of language and of language teaching and learning, the ELT must be carried out to achieve communicative competence. Current investigation on the practices of ELT, however, indicates that English teachers are still walking in place, leaving the CC as a big slogan in their jobs.

The Sweet Smell of … Implicit Helping: Effects of Pleasant Ambient Fragrance on Spontaneous Help in Shopping Malls

ABSTRACT Some studies have shown that pleasant scent encourages the prosocial behavior of people requested for help. However, the effect of pleasant ambient odor on spontaneous helping has never been tested. Male and female confederates accidentally dropped a glove on the floor while walking in places with pleasant ambient odors (e.g., pastries) and in places with no odor. The confederate continued his/her walk, seemingly unaware of his/her loss. It was found that passers-by helped the confederates more favorably in the pleasant-smelling areas. Positive mood induced by ambient smell was used to explain such results.

The Design and Evaluation of a Large-Scale Real-Walking Locomotion Interface

Redirected Free Exploration with Distractors (RFEDs) is a large-scale real-walking locomotion interface developed to enable people to walk freely in Virtual Environments (VEs) that are larger than the tracked space in their facility. This paper describes the RFED system in detail and reports on a user study that evaluated RFED by comparing it to Walking-in-Place (WIP) and Joystick (JS) interfaces. The RFED system is composed of two major components, redirection and distractors. This paper discusses design challenges, implementation details, and lessons learned during the development of two working RFED systems. The evaluation study examined the effect of the locomotion interface on users' cognitive performance on navigation and wayfinding measures. The results suggest that participants using RFED were significantly better at navigating and wayfinding through virtual mazes than participants using walking-in-place and joystick interfaces. Participants traveled shorter distances, made fewer wrong turns, pointed to hidden targets more accurately and more quickly, and were able to place and label targets on maps more accurately, and more accurately estimate the virtual environment size.

Community Walking in People with Parkinson's Disease

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.

Evaluation of walking in place on a Wii balance board to explore a virtual environment

In this work, we present a method of “Walking In Place” (WIP) on the Nintendo Wii Fit Balance Board to explore a virtual environment. We directly compare our method to joystick locomotion and normal walking. The joystick proves inferior to physically walking and to WIP on the Wii Balance Board (WIP--Wii). Interestingly, we find that physically exploring an environment on foot is equivalent in terms of spatial orientation to exploring an environment using our WIP--Wii method. This implies that the WIP--Wii is a good inexpensive alternative to exploring a virtual environment and it may be well--suited for exploring large virtual environments.

Kinematic and behavioral evidence for a distinction between trotting and ambling gaits in the cockroachBlaberus discoidalis

Earlier observations had suggested that cockroaches might show multiple patterns of leg coordination, or gaits, but these were not followed by detailed behavioral or kinematic measurements that would allow a definite conclusion. We measured the walking speeds of cockroaches exploring a large arena and found that the body movements tended to cluster at one of two preferred speeds, either very slow (<10 cm s(-1)) or fairly fast (∼30 cm s(-1)). To highlight the neural control of walking leg movements, we experimentally reduced the mechanical coupling among the various legs by tethering the animals and allowing them to walk in place on a lightly oiled glass plate. Under these conditions, the rate of stepping was bimodal, clustering at fast and slow speeds. We next used high-speed videos to extract three-dimensional limb and joint kinematics for each segment of all six legs. The angular excursions and three-dimensional motions of the leg joints over the course of a stride were variable, but had different distributions in each gait. The change in gait occurs at a Froude number of ∼0.4, a speed scale at which a wide variety of animals show a transition between walking and trotting. We conclude that cockroaches do have multiple gaits, with corresponding implications for the collection and interpretation of data on the neural control of locomotion.

Integration of vestibular and proprioceptive signals for spatial updating

Spatial updating during self-motion typically involves the appropriate integration of both visual and non-visual cues, including vestibular and proprioceptive information. Here, we investigated how human observers combine these two non-visual cues during full-stride curvilinear walking. To obtain a continuous, real-time estimate of perceived position, observers were asked to continuously point toward a previously viewed target in the absence of vision. They did so while moving on a large circular treadmill under various movement conditions. Two conditions were designed to evaluate spatial updating when information was largely limited to either proprioceptive information (walking in place) or vestibular information (passive movement). A third condition evaluated updating when both sources of information were available (walking through space) and were either congruent or in conflict. During both the passive movement condition and while walking through space, the pattern of pointing behavior demonstrated evidence of accurate egocentric updating. In contrast, when walking in place, perceived self-motion was underestimated and participants always adjusted the pointer at a constant rate, irrespective of changes in the rate at which the participant moved relative to the target. The results are discussed in relation to the maximum likelihood estimation model of sensory integration. They show that when the two cues were congruent, estimates were combined, such that the variance of the adjustments was generally reduced. Results also suggest that when conflicts were introduced between the vestibular and proprioceptive cues, spatial updating was based on a weighted average of the two inputs.

A Novel Video Game–Based Device for Measuring Stepping Performance and Fall Risk in Older People

Schoene D, Lord SR, Verhoef P, Smith ST. A novel video game–based device for measuring stepping performance and fall risk in older people. Objective To determine whether a dance mat test of choice stepping reaction time (CSRT) is reliable and can detect differences in fall risk in older adults. Design Randomized order, crossover comparison. Setting Balance laboratory, medical research institute, and retirement village. Participants Older (mean age, 78.87±5.90y; range, 65–90y) independent-living people (N=47) able to walk in place without assistance. Interventions Not applicable. Main Outcome Measures Reaction (RT), movement, and response times of dance pad–based stepping tests, Physiological Profile Assessment (PPA) score, Digit Symbol Substitution Test (DSST) score, time to complete the Trail Making Test (TMT) A+B, Fall Efficacy Scale International (FES-I) score, Activities-specific Balance Confidence (ABC) Scale score, and Incidental and Planned Exercise Questionnaire (IPEQ) incidental IPEQ activity subscore. Results Test-retest reliability of the dance mat CSRT response time was high (intraclass correlation coefficient model 3,k=.90; 95% confidence interval [CI], .82–.94; P<.001) and correlated highly with the existing laboratory-based measure ( r=.86; 95% CI, .75–.92; P<.001). Concurrent validity was shown by significant correlations between response time and measures of fall risk (PPA: r=.42; 95% CI, .15–.63; P<.01; TMT A: r=.61; 95% CI, .39–.77; TMT B: r=.55; 95% CI, .31–.72; DSST: r=−.53; 95% CI, −.71 to −.28; P<.001; FES-I: Spearman ρ=.50; 95% CI, .25–.69; ABC Scale: Spearman ρ=−.58; 95% CI, −.74 to −.35; P<.01). Participants with moderate/high fall-risk scores (PPA score >1) had significantly slower response times than people with low/mild fall-risk scores (PPA score <1) at 1146±182 and 1010±132ms, respectively ( P=.005), and multiple fallers and single/nonfallers showed significant differences in RT (883±137 vs 770±100ms; P=.009) and response time (1180±195 vs 1031±145ms; P=0.017). Conclusions The new dance mat device is a valid and reliable tool for assessing stepping ability and fall risk in older community-dwelling people. Because it is highly portable, it can be used in clinic settings and the homes of older people as both an assessment and training device.

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Studying the neural basis of walking behavior, one often faces the problem that it is hard to separate the neuronally produced stepping output from those leg movements that result from passive forces and interactions with other legs through the common contact with the substrate. If we want to understand, which part of a given movement is produced by nervous system motor output, kinematic analysis of stepping movements, therefore, needs to be complemented with electrophysiological recordings of motor activity. The recording of neuronal or muscular activity in a behaving animal is often limited by the electrophysiological equipment which can constrain the animal in its ability to move with as many degrees of freedom as possible. This can either be avoided by using implantable electrodes and then having the animal move on a long tether (i.e. Clarac et al., 1987; Duch & Pflüger, 1995; Böhm et al., 1997; Gruhn & Rathmayer, 2002) or by transmitting the data using telemetric devices (Kutsch et al, 1993; Fischer et al., 1996; Tsuchida et al. 2004; Hama et al., 2007; Wang et al., 2008). Both of these elegant methods, which are successfully used in larger arthropods, often prove difficult to apply in smaller walking insects which either easily get entangled in the long tether or are hindered by the weight of the telemetric device and its batteries. In addition, in all these cases, it is still impossible to distinguish between the purely neuronal basis of locomotion and the effects exerted by mechanical coupling between the walking legs through the substrate. One solution for this problem is to conduct the experiments in a tethered animal that is free to walk in place and that is locally suspended, for example over a slippery surface, which effectively removes most ground contact mechanics. This has been used to study escape responses (Camhi and Nolen, 1981; Camhi and Levy, 1988), turning (Tryba and Ritzman, 2000a,b; Gruhn et al., 2009a), backward walking (Graham and Epstein, 1985) or changes in velocity (Gruhn et al., 2009b) and it allows the experimenter easily to combine intra- and extracellular physiology with kinematic analyses (Gruhn et al., 2006). We use a slippery surface setup to investigate the timing of leg muscles in the behaving stick insect with respect to touch-down and lift-off under different behavioral paradigms such as straight forward and curved walking in intact and reduced preparations.

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Studying the neural basis of walking behavior, one often faces the problem that it is hard to separate the neuronally produced stepping output from those leg movements that result from passive forces and interactions with other legs through the common contact with the substrate. If we want to understand, which part of a given movement is produced by nervous system motor output, kinematic analysis of stepping movements, therefore, needs to be complemented with electrophysiological recordings of motor activity. The recording of neuronal or muscular activity in a behaving animal is often limited by the electrophysiological equipment which can constrain the animal in its ability to move with as many degrees of freedom as possible. This can either be avoided by using implantable electrodes and then having the animal move on a long tether (i.e. Clarac et al., 1987; Duch & Pflüger, 1995; Böhm et al., 1997; Gruhn & Rathmayer, 2002) or by transmitting the data using telemetric devices (Kutsch et al, 1993; Fischer et al., 1996; Tsuchida et al. 2004; Hama et al., 2007; Wang et al., 2008). Both of these elegant methods, which are successfully used in larger arthropods, often prove difficult to apply in smaller walking insects which either easily get entangled in the long tether or are hindered by the weight of the telemetric device and its batteries. In addition, in all these cases, it is still impossible to distinguish between the purely neuronal basis of locomotion and the effects exerted by mechanical coupling between the walking legs through the substrate. One solution for this problem is to conduct the experiments in a tethered animal that is free to walk in place and that is locally suspended, for example over a slippery surface, which effectively removes most ground contact mechanics. This has been used to study escape responses (Camhi and Nolen, 1981; Camhi and Levy, 1988), turning (Tryba and Ritzman, 2000a,b; Gruhn et al., 2009a), backward walking (Graham and Epstein, 1985) or changes in velocity (Gruhn et al., 2009b) and it allows the experimenter easily to combine intra- and extracellular physiology with kinematic analyses (Gruhn et al., 2006).We use a slippery surface setup to investigate the timing of leg muscles in the behaving stick insect with respect to touch-down and lift-off under different behavioral paradigms such as straight forward and curved walking in intact and reduced preparations.

Computer-Assisted 3D Kinematic Analysis of All Leg Joints in Walking Insects

High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points), our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized.