Aging effect on step adjustments and stability control in visually perturbed gait initiation

Sun, Ruopeng; Cui, Chuyi; Shea, John B.

doi:10.1016/j.gaitpost.2017.08.013

Cited by 17 publications

(21 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been already reported that elderly people show an impaired APA control in response to an unexpected perturbation [40], nonetheless they maintain the ability to adjust the ongoing stepping process in response to a visual perturbation [48]. In this study, the unvaried APA duration altogether with the reduction in unloading phase duration would indicate an earlier step initiation in older than young adults.…”

Section: Discussionmentioning

confidence: 49%

Neuromechanical response of the upper body to unexpected perturbations during gait initiation in young and older adults

et al. 2020

View full text Add to dashboard Cite

Background: Control of upper body motion deteriorates with ageing leading to impaired ability to preserve balance during gait, but little is known on the contribution of the upper body to preserve balance in response to unexpected perturbations during locomotor transitions, such as gait initiation.Aim: To investigate differences between young and older adults in the ability to modify the trunk kinematics and muscle activity following unexpected waist lateral perturbations during gait initiation.Methods: Ten young (25±2yrs) and ten older adults (73±5yrs) initiated locomotion from stance while a lateral pull was randomly applied to the pelvis. Two force plates were used to define the feet centreof-pressure displacement. Angular displacement of the trunk in the frontal plane was obtained through motion analysis. Surface electromyography of cervical and thoracic erector spinae muscles was recorded bilaterally.Results: A lower trunk lateral bending towards the stance leg side in the preparatory phase of gait initiation was observed in older participants following perturbation. Right thoracic muscle activity was increased in response to the perturbation during the initial phase of gait initiation in young (+68%) but not in older participants (+7%). Conclusions:The age-related reduction in trunk movement could indicate a more rigid behaviour of the upper body employed by older compared to young individuals in response to unexpected perturbations preceding the initiation of stepping. Older adults' delayed activation of thoracic muscles could suggest impaired reactive mechanisms that may potentially lead to fall in the early stages of the gait initiation.

show abstract

Section: Discussionmentioning

confidence: 49%

Neuromechanical response of the upper body to unexpected perturbations during gait initiation in young and older adults

et al. 2020

View full text Add to dashboard Cite

show abstract

“…A stronger suppression of i-TA in the elderly could contribute to their larger step angle change (Table 1). Sun et al (2017) found similar results of the step angle change: older adults had more exorotation to lateral target shifts and more endorotation to medial target shifts.…”

Section: Medial Versus Lateral Adjustmentssupporting

confidence: 55%

“…Older adults were found to be particularly poor at making corrections for sideways stepping-target shifts when walking (Hoogkamer et al 2015;Mazaheri et al 2015). Another task in which older adults have been found to have later responses (and a lower accuracy) when adjusting their trajectory is when stepping from quiet stance (gait initiation) (Sun et al 2017;Tseng et al 2009). During obstacle avoidance in walking, it was observed that muscle activation took about 10 ms longer in older adults than in young adults (Weerdesteyn et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Effects of ageing on responses to stepping-target displacements during walking

et al. 2020

View full text Add to dashboard Cite

Purpose Human sensory and motor systems deteriorate with age. When walking, older adults may therefore find it more difficult to adjust their steps to new visual information, especially considering that such adjustments require control of balance as well as of foot trajectory. Our study investigates the effects of ageing on lower limb responses to unpredictable target shifts. Methods Participants walked on a treadmill with projected stepping targets that occasionally shifted in the medial or lateral direction. The shifts occurred at a random moment during the early half of the swing phase of either leg. Kinematic, kinetic and muscle activity data were collected. Results Older adults responded later and corrected for a smaller proportion of the shift than young adults. The order in which muscle activation changed was similar in both groups, with responses of gluteus medius and semitendinosus from about 120 to 140 ms after the shift. Most muscles responded slightly later to lateral target shifts in the older adults than in the young adults, but this difference was not observed for medial target shifts. Ageing delayed the behavioural responses more than it did the electromyographic (EMG) responses. Conclusions Our study suggests that older adults can adjust their walking to small target shifts during the swing phase, but not as well as young adults. Furthermore, muscle strength probably plays a substantial role in the changes in online adjustments during ageing.

show abstract

“…During unperturbed human walking, the spatial and temporal characteristics of the steps are relatively fixed and typically show low step-to-step variability ( Den Otter et al, 2005 ). Step modifications often involve rigorous re-parameterization of forces and require a high level of neuromuscular control ( Sun et al, 2017 ). Consequently, stroke survivors with impaired neuromuscular functioning may be more vulnerable to perturbations of the motor task and ongoing stepping pattern ( Den Otter et al, 2005 ).…”

Section: Introductionmentioning

confidence: 99%

Short-Step Adjustment and Proximal Compensatory Strategies Adopted by Stroke Survivors With Knee Extensor Spasticity for Obstacle Crossing

Huang

Wang

et al. 2020

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

Stroke survivors adopt cautious or compensatory strategies for safe and successful obstacle crossing. Although knee extensor spasticity is a common independent secondary sensorimotor disorder post-stroke, few studies have examined the step adjustment and compensatory strategies used by stroke survivors with knee extensor spasticity during obstacle crossing. This study aimed to compare the differences in the kinematics and kinetics during obstacle crossing between stroke survivors with and without knee extensor spasticity, and to identify knee extensor spasticity-related differences in step adjustment and compensatory strategies. Twenty stroke subjects were divided into a spasticity group [ n = 11, modified Ashworth scale (MAS) ≥ 1] and a non-spasticity group ( n = 9, MAS = 0), based on the MAS score of the knee extensor. Subjects were instructed to walk at a self-selected speed on a 10-m walkway and step over a 15 cm obstacle. A ten-camera 3D motion analysis system and two force plates were used to collect the kinematic and kinetic data. During the pre-obstacle phase, stroke survivors with knee extensor spasticity adopted a short-step strategy to approach the obstacle, while the subjects without spasticity used long-step strategy. During the affected limb swing phase, the spasticity group exhibited increased values that were significantly higher than those seen in the non-spasticity group for the following measurements: pelvic lateral tilt angle, trunk lateral tilt angle, medio-lateral distance between the ankle and ipsilateral hip joint, hip work contributions, the inclination angles between center of mass and center of pressure in anterior–posterior and medio-lateral directions. These results indicate that the combined movement of the pelvic, trunk lateral tilt, and hip abduction is an important compensatory strategy for successful obstacle crossing, but it sacrifices some balance in the sideways direction. During the post-obstacle phase, short-step and increase step width strategy were adopted to reestablish the walking pattern and balance control. These results reveal the step adjustment and compensatory strategies for obstacle crossing and also provide insight into the design of rehabilitation interventions for fall prevention in stroke survivors with knee extensor spasticity.

show abstract

Aging effect on step adjustments and stability control in visually perturbed gait initiation

Cited by 17 publications

References 27 publications

Neuromechanical response of the upper body to unexpected perturbations during gait initiation in young and older adults

Neuromechanical response of the upper body to unexpected perturbations during gait initiation in young and older adults

Effects of ageing on responses to stepping-target displacements during walking

Short-Step Adjustment and Proximal Compensatory Strategies Adopted by Stroke Survivors With Knee Extensor Spasticity for Obstacle Crossing

Contact Info

Product

Resources

About