Interlimb Coordination During Slow Walking in the Cockroach: I. Effects of Substrate Alterations

1979 ◽  
Vol 78 (1) ◽  
pp. 233-243 ◽  
Author(s):  
CARL P. SPIRITO ◽  
DANIEL L. MUSHRUSH
Keyword(s):  
Control System ◽  
Walking Speed ◽  
Interlimb Coordination ◽  
Steering Control ◽  
Inclined Plane ◽  
Slow Walking ◽  
Tripod Gait ◽  
Walking Speeds

In this study, interlimb coordination in the cockroach during slow walking (2–7 steps/s) is described for a variety of substrate conditions. During normal free-walking, the animal utilizes an alternating tripod gait (both ipsilateral and contralateral phase close to 0.50). The protraction/retraction ratio varies linearly with walking speed. When tethered on a supported ball, the ipsilateral phase ranges from 0.32 to 0.46 at walking speeds of 2-7 steps/s, and contralateral phase is constant at 0.53. Protraction/retraction ratios are normal in this case. Blind free-walking animals use a gait which is indistinguishable from normal, but the protraction/retraction ratio is constant over speeds of 2-7 steps/s. When walking down an inclined plane (45°), the gait resembles ball-walking, with an average ipsilateral phase of 0.43 and contralateral phase of 0.53. These alterations of gait under different substrate conditions can be related to the animal's responses to loading, gravity, and steering control system.

Nervous Mechanisms Underlying Intersegmental Co-Ordination of Leg Movements During Walking in the Cockroach

1973 ◽  
Vol 58 (3) ◽  
pp. 725-744
Author(s):  
K. G. PEARSON ◽  
J. F. ILES
Keyword(s):  
Sensory Input ◽  
Walking Speed ◽  
Campaniform Sensilla ◽  
Mutual Inhibition ◽  
Leg Muscles ◽  
Slow Walking ◽  
Tripod Gait ◽  
Walking Speeds ◽  
Generating System ◽  
Leg Movements

1. The activity in identical motoneurones innervating leg muscles of the three thoracic segments of the cockroach has been recorded in (a) normal walking animals, (b) walking animals after lesions to the nervous system and/or amputation of the mesothoracic legs, and (c) restrained de-afferented preparations. 2. The phase of levator motoneurone burst activity of the mesothoracic leg in the metathoracic cycle is almost 0·5 for all walking speeds above 2 steps/sec, confirming that a tripod gait is used at all but the slowest speeds. 3. The burst-generating systems in each segment are centrally coupled because in de-afferented preparations there is a tendency for the bursts in the mesothoraci segment to begin near the end of the metathoracic bursts, and vice versa. 4. Sensory input from leg receptors is also important in co-ordinating stepping movements of the different legs since (a) there are some differences in motoneurone activity of de-afferented and walking preparations, and (b) amputation of the mesothoracic legs at the trochanter leads to an immediate change in the co-ordination of the remaining four legs. 5. It is proposed that two mechanisms are important in co-ordinating leg movements in a slow walking cockroach (a) mutual inhibition between levator burst-generating systems in adjacent ipsilateral legs, and (b) an inhibitory reflex pathway from the campaniform sensilla of the trochanter to the burst-generating system of each leg. The second of these two mechanisms may become less important as the walking speed increases.

scholarly journals Drosophila uses a tripod gait across all walking speeds, and the geometry of the tripod is important for speed control

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Chanwoo Chun ◽  
Tirthabir Biswas ◽  
Vikas Bhandawat
Keyword(s):  
Simple Model ◽  
Spatial Resolution ◽  
Inverted Pendulum ◽  
Walking Speed ◽  
High Spatial Resolution ◽  
Center Of Mass ◽  
Mass Movement ◽  
Speed Control ◽  
Tripod Gait ◽  
Walking Speeds

Changes in walking speed are characterized by changes in both the animal’s gait and the mechanics of its interaction with the ground. Here we study these changes in walking Drosophila. We measured the fly’s center of mass movement with high spatial resolution and the position of its footprints. Flies predominantly employ a modified tripod gait that only changes marginally with speed. The mechanics of a tripod gait can be approximated with a simple model – angular and radial spring-loaded inverted pendulum (ARSLIP) – which is characterized by two springs of an effective leg that become stiffer as the speed increases. Surprisingly, the change in the stiffness of the spring is mediated by the change in tripod shape rather than a change in stiffness of individual legs. The effect of tripod shape on mechanics can also explain the large variation in kinematics among insects, and ARSLIP can model these variations.

scholarly journals Optimized hip–knee–ankle exoskeleton assistance at a range of walking speeds

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Gwendolyn M. Bryan ◽  
Patrick W. Franks ◽  
Seungmoon Song ◽  
Alexandra S. Voloshina ◽  
Ricardo Reyes ◽  
...  
Keyword(s):  
Walking Speed ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Positive Power ◽  
Fast Walking ◽  
Slow Walking ◽  
Limited Success ◽  
Ankle Exoskeleton ◽  
Walking Speeds ◽  
The Relationship

Abstract Background Autonomous exoskeletons will need to be useful at a variety of walking speeds, but it is unclear how optimal hip–knee–ankle exoskeleton assistance should change with speed. Biological joint moments tend to increase with speed, and in some cases, optimized ankle exoskeleton torques follow a similar trend. Ideal hip–knee–ankle exoskeleton torque may also increase with speed. The purpose of this study was to characterize the relationship between walking speed, optimal hip–knee–ankle exoskeleton assistance, and the benefits to metabolic energy cost. Methods We optimized hip–knee–ankle exoskeleton assistance to reduce metabolic cost for three able-bodied participants walking at 1.0 m/s, 1.25 m/s and 1.5 m/s. We measured metabolic cost, muscle activity, exoskeleton assistance and kinematics. We performed Friedman’s tests to analyze trends across walking speeds and paired t-tests to determine if changes from the unassisted conditions to the assisted conditions were significant. Results Exoskeleton assistance reduced the metabolic cost of walking compared to wearing the exoskeleton with no torque applied by 26%, 47% and 50% at 1.0, 1.25 and 1.5 m/s, respectively. For all three participants, optimized exoskeleton ankle torque was the smallest for slow walking, while hip and knee torque changed slightly with speed in ways that varied across participants. Total applied positive power increased with speed for all three participants, largely due to increased joint velocities, which consistently increased with speed. Conclusions Exoskeleton assistance is effective at a range of speeds and is most effective at medium and fast walking speeds. Exoskeleton assistance was less effective for slow walking, which may explain the limited success in reducing metabolic cost for patient populations through exoskeleton assistance. Exoskeleton designers may have more success when targeting activities and groups with faster walking speeds. Speed-related changes in optimized exoskeleton assistance varied by participant, indicating either the benefit of participant-specific tuning or that a wide variety of torque profiles are similarly effective.

scholarly journals Influence of walking speed on locomotor time production

2013 ◽  
Author(s):  
Fabrice MEGROT ◽  
Carole MEGROT
Keyword(s):  
Healthy Subjects ◽  
Walking Speed ◽  
The Other ◽  
Temporal Perception ◽  
Time Production ◽  
Fast Walking ◽  
Slow Walking ◽  
Perception Of Time ◽  
Walking Speeds

The aim of the present study was to determine whether or not walking speed affects temporal perception. It was hypothesized that fast walking would reduce the perceived length of time while slow walking increase production estimates. 16 healthy subjects were included. After a first « calibration » phase allowing the determination of different walking speeds, the subjects were instructed to demonstrate periods of time or « target times » of 3s and 7s, by a walking movement. Then, subjects were asked to simulate walking by raising one foot after the other without advancing. Finally, a third condition, Motionless, involved producing the target times while standing without movement. The results of this study suggest that movement does influence the perception of time, causing an overestimation of time. In agreement with the results of Denner et al. (1963) the subjects produced times which were longer than the target times.

The Control of Walking in Orthoptera

1973 ◽  
Vol 58 (1) ◽  
pp. 45-58
Author(s):  
M. D. BURNS
Keyword(s):  
Walking Speed ◽  
Schistocerca Gregaria ◽  
Relative Independence ◽  
Straight Line ◽  
Tripod Gait ◽  
High Level ◽  
Walking Speeds ◽  
Leg Movements

1. The patterns of leg movements during normal straight-line walking of the locust Schistocerca gregaria and the grasshopper Romalea microptera were recorded and analysed. 2. The ratio of protraction to retraction increased with walking speed except in the prothoracic legs. At any one speed both protraction and retraction durations were variable but the variation was greatest for protraction. 3. The locust employed an alternating tripod gait at all walking speeds recorded (2-8 steps/sec.) It displayed a high level of variability in its leg movements which appeared to be held in check by stabilising mechanisms operating on the first and last leg pairs. 4. The movements of individual legs of the grasshopper were very similar to those of the locust but the gait used was not alternating tripod. 5. Comparisons were made with other insects and it was suggested that the specialization of the metathoracic legs in the locust gave rise to most of the variability in leg movements and that the relative independence of the prothoracic legs reflects an exploratory role in walking.

scholarly journals The Association of Vision, Hearing, and Dual Sensory Impairments With Walking Speed and Incident Slow Walking

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 216-216
Author(s):  
Ahmed Shakarchi ◽  
Varshini Varadaraj ◽  
Lama Assi ◽  
Nicholas Reed ◽  
Bonnielin Swenor
Keyword(s):  
Older Adults ◽  
Walking Speed ◽  
Linear Models ◽  
Population Based ◽  
Adverse Outcomes ◽  
Sensory Impairment ◽  
Slow Walking ◽  
Increased Risk ◽  
Sensory Impairments ◽  
Walking Speeds

Abstract Vision (VI), hearing (HI) and dual sensory (DSI, concurrent VI and HI) impairments are increasing in prevalence as populations age. Walking speed is an established health indicator associated with adverse outcomes, including mortality. Using the population-based Health and Retirement Study, we analyzed the longitudinal relationship between sensory impairment and walking speed. In multivariable mixed-effects linear models, we found differences in baseline walking speed (m/s) by sensory impairment: Beta=-0.05 (95%CI=-0.07, -0.04), Beta=-0.02 (95%CI=--0.03, -0.003), and Beta=-0.07 (95%CI=--0.08, -0.05) for VI, HI and DSI, respectively, as compared to those without sensory impairment. However, similar annual declines (0.014 m/s) in walking speeds occurred in all groups. In time-to-event analyses, events were defined as “slow walking” (speed <0.60m/s) and “very slow walking” (<0.40m/s). Incident “slow walking” was 43% (95%CI=25%, 65%), 29% (95%CI=13%, 48%) and 35% (95%CI=13%, 61%) greater in VI, HI and DSI, respectively, than the no sensory impairment group, while incident “very slow walking” was 21% (95%CI=-4%, 54%), 30% (95%CI=3%, 63%) and 89% (95%CI=47%, 143%) greater; the increase was significantly greater in DSI than VI and HI. These results suggest that older adults with vision and hearing impairments walk slower and are at increased risk of slow walking than older adults without these sensory impairments. Additionally, older adults with DSI are at greatest risk of very slow walking.

Identification of Disability Risk in Addition to Slow Walking Speed in Older Adults

Gerontology ◽  
2021 ◽  
pp. 1-10
Author(s):  
Hiroyuki Shimada ◽  
Takehiko Doi ◽  
Sangyoon Lee ◽  
Kota Tsutsumimoto ◽  
Seongryu Bae ◽  
...  
Keyword(s):  
Older Adults ◽  
Regression Models ◽  
Walking Speed ◽  
Word List ◽  
Normal Walking ◽  
Slow Walking ◽  
List Memory ◽  
Walking Speeds ◽  
Walking Group ◽  
Slow Walking Speed

<b><i>Introduction:</i></b> A cutoff speed of 1.0 m/s for walking at a comfortable pace is critical for predicting future functional decline. However, some older adults with walking speeds below the cutoff point maintain an independent living. We aimed to identify specific predictors of disability development in older adults with slow walking speeds in contrast to those with a normal walking speed. <b><i>Methods:</i></b> This prospective cohort study on 12,046 community-dwelling independent Japanese older adults (mean age, 73.6 ± 5.4 years) was conducted between 2011 and 2015. Participants were classified into slow walking speed (comfortable walking speed slower than 1.0 m/s) and normal walking speed (speed of 1.0 m/s or faster) groups and followed up to assess disability incidence for 24 months after baseline assessments. Cox proportional hazards regression models were used to identify predictors of disability development in the slow and normal walking groups. <b><i>Results:</i></b> Overall, 26.8% of participants had a slow walking speed. At follow-up, 17.3% and 5.1% of participants in the slow and normal walking groups, respectively, developed disability (<i>p</i> &#x3c; 0.01). Cox regression models revealed that age (hazard ratio 1.07, 95% confidence interval 1.05–1.09), walking speed (0.12, 0.07–0.22), grip strength (0.97, 0.95–0.99), Parkinson’s disease (4.65, 2.59–8.33), word list memory-immediate recognition score (0.90, 0.85–0.97), word list memory-delayed recall score (0.94, 0.89–1.00), Symbol Digit Substitution Test (SDST) score (0.98, 0.96–0.99), and 15-item Geriatric Depression Scale (GDS) score (1.04, 1.01–1.07) were significantly associated with disability incidence in the slow walking group. In the normal walking group, age, grip strength, depression, diabetes, cognition, GDS score, and reduced participation in outdoor activity were significantly associated with disability incidence; however, there was no significant association with walking speed. <b><i>Conclusions:</i></b> Decreased walking speeds have considerably greater impact on disability development in older adults with a slow walking speed than in those with a normal walking speed. Health-care providers should explore modifiable factors for reducing walking speed; they should also encourage improvement of risk factors such as muscle weakness and depression to reduce disability risk in older adults with slow walking speeds.

scholarly journals “Stepping Up” Activity Poststroke: Ankle-Positioned Accelerometer Can Accurately Record Steps During Slow Walking

2016 ◽  
Vol 96 (3) ◽  
pp. 355-360 ◽  
Author(s):  
Tara D. Klassen ◽  
Lisa A. Simpson ◽  
Shannon B. Lim ◽  
Dennis R. Louie ◽  
Beena Parappilly ◽  
...  
Keyword(s):  
Walking Speed ◽  
Cross Sectional Study ◽  
Community Dwelling ◽  
Cross Sectional ◽  
Rehabilitation Professionals ◽  
Video Recordings ◽  
Slow Walking ◽  
Walking Activity ◽  
All Speeds ◽  
Walking Speeds

Background As physical activity in people poststroke is low, devices that monitor and provide feedback of walking activity provide motivation to engage in exercise and may assist rehabilitation professionals in auditing walking activity. However, most feedback devices are not accurate at slow walking speeds. Objective This study assessed the accuracy of one accelerometer to measure walking steps of community-dwelling individuals poststroke. Design This was a cross-sectional study. Methods Two accelerometers were positioned on the nonparetic waist and ankle of participants (N=43), and walking steps from these devices were recorded at 7 speeds (0.3–0.9 m/s) and compared with video recordings (gold standard). Results When positioned at the waist, the accelerometer had more than 10% error at all speeds, except 0.8 and 0.9 m/s, and numerous participants recorded zero steps at 0.3 to 0.5 m/s. The device had 10% or less error when positioned at the ankle for all speeds between 0.4 and 0.9 m/s. Limitations Some participants were unable to complete the faster walking speeds due to their walking impairments and inability to maintain the requested walking speed. Conclusions Although not recommended by the manufacturer, positioning the accelerometer at the ankle (compared with the waist) may fill a long-standing need for a readily available device that provides accurate feedback for the altered and slow walking patterns that occur with stroke.

scholarly journals Split-Belt Treadmill Adaptation Shows Different Functional Networks for Fast and Slow Human Walking

2010 ◽  
Vol 103 (1) ◽  
pp. 183-191 ◽  
Author(s):  
Erin V. L. Vasudevan ◽  
Amy J. Bastian
Keyword(s):  
Walking Speed ◽  
Healthy Adult ◽  
Motor Pattern ◽  
Specific Pattern ◽  
Functional Networks ◽  
Slow Walking ◽  
Partial Overlap ◽  
Walking Speeds ◽  
Short Time ◽  
Slow Walking Speed

New walking patterns can be learned over short time scales (i.e., adapted in minutes) using a split-belt treadmill that controls the speed of each leg independently. This leads to storage of a modified motor pattern that is expressed as an aftereffect in regular walking conditions and must be de-adapted to return to normal. Here we asked whether the nervous system adapts a general walking pattern that is used across many speeds or a specific pattern affecting only the two speeds experienced during split-belt training. In experiment 1, we tested three groups of healthy adult subjects walking at different split-belt speed combinations and then assessed aftereffects at a range of speeds. We found that aftereffects were largest at the slower speed that was used in split-belt training in all three groups, and it decayed gradually for all other speeds. Thus adaptation appeared to be more strongly linked to the slow walking speed. This result suggests a separation in the functional networks used for fast and slow walking. We tested this in experiment 2 by adapting walking to split belts and then determining how much fast regular walking washed out the slow aftereffect and vice versa. We found that 23–38% of the aftereffect remained regardless of which speed was washed out first. This demonstrates that there is only partial overlap in the functional networks coordinating different walking speeds. Taken together, our results suggest that there are some neural networks for controlling locomotion that are recruited specifically for fast versus slow walking in humans, similar to recent findings in other vertebrates.

A study of the accuracy of the Fitbit Zip in measuring steps both indoors and outdoors in a mixed rehabilitation population

2021 ◽  
pp. 026921552110352
Author(s):  
Craig Farmer ◽  
Maayken EL van den Berg ◽  
Sally Vuu ◽  
Christopher J Barr
Keyword(s):  
Walking Speed ◽  
Random Order ◽  
Step Count ◽  
Outpatient Rehabilitation ◽  
Rehabilitation Hospital ◽  
Slow Walking ◽  
Walking Speeds ◽  
Minute Walk ◽  
Slow Walking Speed ◽  
Indoor And Outdoor

Objective: To assess (1) step count accuracy of the Fitbit Zip, compared to manual step count, in people receiving outpatient rehabilitation, in indoor and outdoor conditions, and (2) impact of slow walking speed on Fitbit accuracy. Design: Observational study. Setting: A metropolitan rehabilitation hospital. Subjects: Adults ( n = 88) attending a subacute rehabilitation outpatient clinic with walking speeds of between 0.4 and 1.0 m/s. Interventions: Two 2-minute walk tests, one indoors and one outdoors, completed in random order. Main measures: Step count recorded manually by observation and by a Fitbit Zip, attached to the shoe on the dominant or non-affected side. Subgroup analysis included assessment accuracy for those considered limited community walkers (slower than 0.8 m/s) and those considered community walkers (faster than 0.8 m/s). Results: The Fitbit significantly ( P < 0.05) undercounted steps compared to manual step count, indoors and outdoors, with percentage agreement slightly higher outdoors (mean 92.4%) than indoors (90.1%). Overall, there was excellent consistent agreement between the Fitbit and manual step count for both indoor (ICC 0.83) and outdoor (ICC 0.88) walks. The accuracy of the Fitbit was significantly ( P < 0.05) reduced in those who walked slower than 0.8 m/s outdoors (ICC 0.80) compared to those who walk faster than 0.8 m/s (ICC 0.90). Conclusions: The Fitbit Zip shows high step count accuracy with manual step count in a mixed subacute rehabilitation population. However, accuracy is affected by walking speed, with decreased accuracy in limited community walkers.

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