Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry

Essential tremor (ET) is a common movement disorder that causes motor deficits similar to those seen in cerebellar disorders. These include kinetic tremor, gait ataxia, and impaired motor adaptation. Previous studies of motor adaptation in ET have focused on reaching while the effects of ET on gait adaptation are currently unknown. The purpose of this study was to contrast locomotor adaptation in persons with and without ET. We hypothesized that persons with ET would show impaired gait adaptation. In a cross-sectional study, persons with ET ( n = 14) and healthy matched controls ( n = 12) walked on a split-belt treadmill. Participants walked with the belts moving at a 2:1 ratio, followed by overground walking to test transfer, followed by a readaptation period and finally a deadaptation period. Step length asymmetry was measured to assess the rate of adaptation, amount of transfer, and rates of readaptation and deadaptation. Spatial, temporal, and velocity contributions to step length asymmetry were analyzed during adaptation. There were no group by condition interactions in step length asymmetry or contributions to step length asymmetry. Regardless of condition, persons with ET walked slower and exhibited lower temporal ( P < 0.001) and velocity ( P = 0.001) contributions to step length asymmetry than controls. Persons with ET demonstrated a preserved ability to adapt to, store, and transfer a new walking pattern. Despite probable cerebellar involvement in ET, locomotor adaptation is an available mechanism to teach persons with ET new gait patterns. NEW & NOTEWORTHY This study is the first to investigate walking adaptation abilities of people with essential tremor. Despite evidence of cerebellar impairment in this population, people with essential tremor can adapt their walking patterns. However, people with essential tremor do not modulate the timing of their footsteps to meet walking demands. Therefore, this study is the first to report impairments in the temporal aspects of walking in people with essential tremor during both typical and locomotor learning.

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Contributions of spatial and temporal control of step length symmetry in the transfer of locomotor adaptation from a motorized to a non-motorized split-belt treadmill

10.1101/699736 ◽

2019 ◽

Author(s):

Daniel L. Gregory ◽

Frank C. Sup ◽

Julia T. Choi

Keyword(s):

Repeated Measures ◽

Step Length ◽

Treadmill Walking ◽

The Body ◽

Speed Ratio ◽

Temporal Control ◽

After Effects ◽

Locomotor Adaptation ◽

Length Difference ◽

Motor Outputs

AbstractBackgroundLocomotor adaptation during motorized split-belt walking depends on independent processes for spatial and temporal control of step length symmetry. The unique mechanics of motorized split-belt walking that constrains two limbs to move at different speeds during double support may limit transfer of step length adaptations to new walking contexts.Research questionHow do spatial and temporal locomotor outputs contribute to transfer of step length adaptation from constrained motorized split-belt walking to unconstrained non-motorized split-belt walking?MethodsWe built a non-motorized split-belt treadmill that allows the user to walk at their own pace while simultaneously allowing the two belts to be self-propelled at different speeds. 10 healthy young participants walked on the non-motorized split-belt treadmill after an initial 10-minute adaptation on the motorized split-belt with a 2:1 speed ratio. Foot placement relative to the body and timing between heel strikes were calculated to determine spatial and temporal motor outputs, respectively. Separate repeated measures ANOVAs were used for step length difference and its spatial and temporal components to assess for transfer to the non-motorized treadmill.ResultsWe found robust after-effects in step length difference during transfer to non-motorized split-belt treadmill walking that were primarily driven by changes in temporal motor outputs. Conversely, residual after-effects observed during motorized tied-belt treadmill walking (post-transfer) were driven by changes in spatial motor outputs.SignificanceOur data showed decoupling of adapted spatial and temporal locomotor outputs during the transfer to non-motorized split-belt walking, raising the new possibility of using a non-motorized split-belt treadmill to target specific spatial or temporal gait deficits.

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Incremental Visual Occlusion During Split-Belt Treadmill Walking Has No Gradient Effect on Adaptation or Retention

Perceptual and Motor Skills ◽

10.1177/00315125211050322 ◽

2021 ◽

pp. 003151252110503

Author(s):

Amanda E. Stone ◽

Adam C. Hockman ◽

Jaimie A. Roper ◽

Chris J. Hass

Keyword(s):

Visual Field ◽

Repeated Measures ◽

Visual Information ◽

Step Length ◽

Group Differences ◽

Lower Visual Field ◽

Normal Vision ◽

Locomotor Adaptation ◽

Visual Occlusion ◽

Length Standard

Split-belt treadmills have become an increasingly popular means of quantifying ambulation adaptability. Multiple sensory feedback mechanisms, including vision, contribute to task execution and adaptation success. No studies have yet explored visual feedback effects on locomotor adaptability across a spectrum of available visual information. In this study, we sought to better understand the effects of visual information on locomotor adaptation and retention by directly comparing incremental levels of visual occlusion. Sixty healthy young adults completed a split-belt adaptation protocol, including a baseline, asymmetric walking condition (adapt), a symmetric walking condition (de-adapt), and another asymmetric walking condition (re-adapt). We randomly assigned participants into conditions with varied visual occlusion (i.e., complete and lower visual field occlusion, or normal vision). We captured kinematic data, and outcome measures included magnitude of asymmetry, spatial and temporal contributions to step length asymmetry, variability of the final adapted pattern, and magnitude of adaptation. We used repeated measures and four-way MANOVAs to examine the influence of visual occlusion and walking condition. Participants with complete, compared to lower visual field visual occlusion displayed less consistency in their walking pattern, evident via increased step length standard deviation ( p = .007, d = 0.89), and compared to normal vision groups ( p = .003 d = 0.81). We found no other group differences, indicating that varying levels of visual occlusion did not significantly affect locomotor adaptation or retention. This study offers insight into the role vision plays in locomotor adaptation and retention with clinical utility for improving variability in step control.

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Blocking trial-by-trial error correction does not interfere with motor learning in human walking

Journal of Neurophysiology ◽

10.1152/jn.00941.2015 ◽

2016 ◽

Vol 115 (5) ◽

pp. 2341-2348 ◽

Cited By ~ 19

Author(s):

Andrew W. Long ◽

Ryan T. Roemmich ◽

Amy J. Bastian

Keyword(s):

Error Correction ◽

Motor Pattern ◽

Step Length ◽

The Other ◽

Human Walking ◽

Not Given ◽

Foot Placement ◽

Locomotor Adaptation ◽

Walking Pattern ◽

Environmental Demands

Movements can be learned implicitly in response to new environmental demands or explicitly through instruction and strategy. The former is often studied in an environment that perturbs movement so that people learn to correct the errors and store a new motor pattern. Here, we demonstrate in human walking that implicit learning of foot placement occurs even when an explicit strategy is used to block changes in foot placement during the learning process. We studied people learning a new walking pattern on a split-belt treadmill with and without an explicit strategy through instruction on where to step. When there is no instruction, subjects implicitly learn to place one foot in front of the other to minimize step-length asymmetry during split-belt walking, and the learned pattern is maintained when the belts are returned to the same speed, i.e., postlearning. When instruction is provided, we block expression of the new foot-placement pattern that would otherwise naturally develop from adaptation. Despite this appearance of no learning in foot placement, subjects show similar postlearning effects as those who were not given any instruction. Thus locomotor adaptation is not dependent on a change in action during learning but instead can be driven entirely by an unexpressed internal recalibration of the desired movement.

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Contributions of spatial and temporal control of step length symmetry in the transfer of locomotor adaptation from a motorized to a non-motorized split-belt treadmill

Royal Society Open Science ◽

10.1098/rsos.202084 ◽

2021 ◽

Vol 8 (2) ◽

Author(s):

Daniel L. Gregory ◽

Frank C. Sup ◽

Julia T. Choi

Keyword(s):

Step Length ◽

Treadmill Walking ◽

Speed Ratio ◽

Foot Placement ◽

After Effects ◽

Locomotor Adaptation ◽

Locomotor Control ◽

Length Difference ◽

Limb Coordination ◽

Healthy Participants

Walking requires control of where and when to step for stable interlimb coordination. Motorized split-belt treadmills which constrain each leg to move at different speeds lead to adaptive changes to limb coordination that result in after-effects (e.g. gait asymmetry) on return to normal treadmill walking. These after-effects indicate an underlying neural adaptation. Here, we assessed the transfer of motorized split-belt treadmill adaptations with a custom non-motorized split-belt treadmill where each belt can be self-propelled at different speeds. Transfer was indicated by the presence of after-effects in step length, foot placement and step timing differences. Ten healthy participants adapted on a motorized split-belt treadmill (2 : 1 speed ratio) and were then assessed for after-effects during subsequent non-motorized treadmill and motorized tied-belt treadmill walking. We found that after-effects in step length difference during transfer to non-motorized split-belt walking were primarily associated with step time differences. Conversely, residual after-effects during motorized tied-belt walking following transfer were associated with foot placement differences. Our data demonstrate decoupling of adapted spatial and temporal locomotor control during transfer to a novel context, suggesting that foot placement and step timing control can be independently modulated during walking.

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Different Error Size During Locomotor Adaptation Affects Transfer to Overground Walking Poststroke

Neurorehabilitation and Neural Repair ◽

10.1177/1545968318809921 ◽

2018 ◽

Vol 32 (12) ◽

pp. 1020-1030 ◽

Cited By ~ 7

Author(s):

Carolina C. Alcântara ◽

Charalambos C. Charalambous ◽

Susanne M. Morton ◽

Thiago L. Russo ◽

Darcy S. Reisman

Keyword(s):

Catch Trial ◽

Step Length ◽

Similar Amount ◽

Adaptation Period ◽

Overground Walking ◽

Locomotor Adaptation ◽

Walking Pattern ◽

Gradual Group ◽

Adaptation Response ◽

Group A

Background. Studies in neurologically intact subjects suggest that the gradual presentation of small perturbations (errors) during learning results in better transfer of a newly learned walking pattern to overground walking. Whether the same result would be true after stroke is not known. Objective. To determine whether introducing gradual perturbations, during locomotor learning using a split-belt treadmill influences learning the novel walking pattern or transfer to overground walking poststroke. Methods. Twenty-six chronic stroke survivors participated and completed the following walking testing paradigm: baseline overground walking; baseline treadmill walking; split-belt treadmill/adaptation period (belts moving at different speeds); catch trial (belts at same speed); post overground walking. Subjects were randomly assigned to the Gradual group (gradual changes in treadmill belts speed during adaptation) or the Abrupt group (a single, large, abrupt change during adaptation). Step length asymmetry adaptation response on the treadmill and transfer of learning to overground walking was assessed. Results. Step length asymmetry during the catch trial was the same between groups ( P = .195) confirming that both groups learned a similar amount. The magnitude of transfer to overground walking was greater in the Gradual than in the Abrupt group ( P = .041). Conclusions. The introduction of gradual perturbations (small errors), compared with abrupt (larger errors), during a locomotor adaptation task seems to improve transfer of the newly learned walking pattern to overground walking poststroke. However, given the limited magnitude of transfer, future studies should examine other factors that could impact locomotor learning and transfer poststroke.

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Augmenting propulsion demands during split-belt walking increases locomotor adaptation in the asymmetric motor system

10.1101/734749 ◽

2019 ◽

Author(s):

Carly J. Sombric ◽

Gelsy Torres-Oviedo

Keyword(s):

Neurological Disorders ◽

Motor System ◽

Motor Behavior ◽

Motor Adaptation ◽

Chronic Phase ◽

Step Length ◽

After Effects ◽

Post Stroke ◽

Locomotor Adaptation ◽

Rehabilitation Strategy

AbstractBackgroundPromising studies have shown that the mobility of individuals with hemiparesis due to brain lesions, such as stroke, can improve through motor adaptation protocols forcing patients to use their affected limb more. However, little is known about how to facilitate this process. Here we asked if increasing propulsion demands during split-belt walking (i.e., legs moving at different speeds) leads to more motor adaptation and more symmetric gait in survivors of a stroke, as we previously observed in subjects without neurological disorders.MethodsWe investigated the effect of propulsion forces on locomotor adaptation during and after split-belt walking in the asymmetric motor system post-stroke. To test this, 12 subjects in the chronic phase post-stroke experienced a split-belt protocol in a flat and incline session so as to contrast the effects of two different propulsion demands. Step length asymmetry and propulsion forces were used to compare the motor behavior between the two sessions because these are clinically relevant measures that are altered by split-belt walking.ResultsThe incline session resulted in more symmetric step lengths during late split-belt walking and larger after-effects following split-belt walking. In both testing sessions, subjects who have had a stroke adapted to regain speed and slope-specific leg orientations similarly to young, intact adults. Importantly, leg orientations during baseline walking were predictive of those achieved during split-belt walking, which in turn predicted each individual’s post-adaptation behavior.ConclusionThese results indicated that survivors of a stroke can adapt their movements to meet leg-specific kinetic demands. This promising finding suggests that augmenting propulsion demands during split-belt walking could favor symmetric walking in individuals who had a stroke, possibly making split-belt interventions a more effective gait rehabilitation strategy.

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Sensory-Motor Mechanisms Increasing Falls Risk in Diabetic Peripheral Neuropathy

Medicina ◽

10.3390/medicina57050457 ◽

2021 ◽

Vol 57 (5) ◽

pp. 457

Author(s):

Neil D. Reeves ◽

Giorgio Orlando ◽

Steven J. Brown

Keyword(s):

Peripheral Neuropathy ◽

Diabetic Peripheral Neuropathy ◽

Motor Nerve ◽

Step Length ◽

Falls Prevention ◽

Motor Deficits ◽

Falls Risk ◽

Walking Gait ◽

Risk Of Falls ◽

Diabetes Patients

Diabetic peripheral neuropathy (DPN) is associated with peripheral sensory and motor nerve damage that affects up to half of diabetes patients and is an independent risk factor for falls. Clinical implications of DPN-related falls include injury, psychological distress and physical activity curtailment. This review describes how the sensory and motor deficits associated with DPN underpin biomechanical alterations to the pattern of walking (gait), which contribute to balance impairments underpinning falls. Changes to gait with diabetes occur even before the onset of measurable DPN, but changes become much more marked with DPN. Gait impairments with diabetes and DPN include alterations to walking speed, step length, step width and joint ranges of motion. These alterations also impact the rotational forces around joints known as joint moments, which are reduced as part of a natural strategy to lower the muscular demands of gait to compensate for lower strength capacities due to diabetes and DPN. Muscle weakness and atrophy are most striking in patients with DPN, but also present in non-neuropathic diabetes patients, affecting not only distal muscles of the foot and ankle, but also proximal thigh muscles. Insensate feet with DPN cause a delayed neuromuscular response immediately following foot–ground contact during gait and this is a major factor contributing to increased falls risk. Pronounced balance impairments measured in the gait laboratory are only seen in DPN patients and not non-neuropathic diabetes patients. Self-perception of unsteadiness matches gait laboratory measures and can distinguish between patients with and without DPN. Diabetic foot ulcers and their associated risk factors including insensate feet with DPN and offloading devices further increase falls risk. Falls prevention strategies based on sensory and motor mechanisms should target those most at risk of falls with DPN, with further research needed to optimise interventions.

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Acute Effects on Impact Accelerations Running with Objects in the Hand

Life ◽

10.3390/life11060550 ◽

2021 ◽

Vol 11 (6) ◽

pp. 550

Author(s):

Roberto Sanchis-Sanchis ◽

Alberto Encarnación-Martínez ◽

Jose I. Priego-Quesada ◽

Inmaculada Aparicio ◽

Irene Jimenez-Perez ◽

...

Keyword(s):

Mobile Phone ◽

Step Length ◽

Stride Frequency ◽

Acute Effects ◽

Shock Attenuation ◽

Acceleration Rate ◽

Recreational Runners ◽

Impact Acceleration ◽

Spatio Temporal ◽

Extra Weight

Amateur runners usually run carrying implements in their hands (keys, a mobile phone, or a bottle of water). However, there is a lack of literature about the effects of different handloads on impact accelerations. Thus, this study aimed to analyse the effects of carrying different objects in the hand on impact accelerations during running. Nineteen male recreational runners (age 24.3 ± 6.8 years, training volume of 25 ± 7.38 km/week) performed twenty minutes of running on a treadmill at 2.78 m/s with four different conditions: no extra weight, with keys, with a mobile phone, and with a bottle of water. Impact acceleration and spatio-temporal parameters were analysed through a wireless triaxial accelerometry system composed of three accelerometers: two placed in each tibia and one placed on the forehead. A higher tibia acceleration rate in the dominant leg was observed when participants ran holding both a mobile phone (p = 0.027; ES = 0.359) and a bottle of water (p = 0.027; ES = 0.359), compared to no extra weight. No changes were observed in peak acceleration, acceleration magnitude, and shock attenuation in any other conditions. Likewise, neither stride frequency nor step length was modified. Our results suggest that recreational runners should not worry about carrying objects in their hands, like a mobile phone or a bottle of water, in short races because their effect seems minimal.

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Optimized stable gait planning of biped robot using multi-objective evolutionary JAYA algorithm

International Journal of Advanced Robotic Systems ◽

10.1177/1729881420976344 ◽

2020 ◽

Vol 17 (6) ◽

pp. 172988142097634

Author(s):

Huan Tran Thien ◽

Cao Van Kien ◽

Ho Pham Huy Anh

Keyword(s):

Inverse Kinematics ◽

Biped Robot ◽

Step Length ◽

Jaya Algorithm ◽

Kinetic Chain ◽

Biped Walking ◽

Gait Planning ◽

Multi Objective ◽

Simulation And Experiment ◽

Stable Gait

This article proposes a new stable biped walking pattern generator with preset step-length value, optimized by multi-objective JAYA algorithm. The biped robot is modeled as a kinetic chain of 11 links connected by 10 joints. The inverse kinematics of the biped is applied to derive the specified biped hip and feet positions. The two objectives related to the biped walking stability and the biped to follow the preset step-length magnitude have been fully investigated and Pareto optimal front of solutions has been acquired. To demonstrate the effectiveness and superiority of proposed multi-objective JAYA, the results are compared to those of MO-PSO and MO-NSGA-2 optimization approaches. The simulation and experiment results investigated over the real small-scaled biped HUBOT-4 assert that the multi-objective JAYA technique ensures an outperforming effective and stable gait planning and walking for biped with accurate preset step-length value.

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