• Agreement
• Anticipatory postural adjustments
• Connected insoles
• Device validation
• Step initiation

• Humans
• Male
• Young Adult
• Female
• Adult
• Gait/physiology
• Algorithms
• Wearable Electronic Devices
• Shoes
• Biomechanical Phenomena
• Walking/physiology

• go-before-you-know
• margin of stability
• postural stability
• sensorimotor control

• Humans
• Male
• Adult
• Female
• Young Adult
• Postural Balance/physiology
• Psychomotor Performance/physiology
• Probability
• Motor Activity/physiology
• Posture/physiology
• Biomechanical Phenomena

• 21J10930 MEXT | Japan Society for the Promotion of Science (JSPS)
• 24KJ1843 MEXT | Japan Society for the Promotion of Science (JSPS)

• eyes close (EC)
• foot height
• motor image
• motor planning
• step length
• walking

• Balance
• adaptation
• anticipatory postural adjustments
• biomechanics
• centre of pressure
• step

• Humans
• Gymnastics/physiology
• Walking/physiology
• Biomechanical Phenomena
• Male
• Female
• Young Adult
• Weight-Bearing/physiology
• Adolescent
• Postural Balance/physiology
• Posture/physiology
• Adaptation, Physiological
• Adult
• Anticipation, Psychological

• Humans
• Postural Balance/physiology
• Female
• Male
• Adult
• Vision, Ocular/physiology
• Standing Position
• Young Adult
• Posture/physiology
• Biomechanical Phenomena

• Bayes factor 01
• Bland–Altman
• Parkinson’s disease
• biomechanics
• force plate
• gait initiation
• healthy adults
• margin of stability
• markerless motion capture

• Humans
• Parkinson Disease/physiopathology
• Gait/physiology
• Aged
• Postural Balance/physiology
• Male
• Female
• Adult
• Middle Aged
• Young Adult
• Biomechanical Phenomena/physiology
• Motion Capture

• CIFRE N◦2020/1053 Agence national de la recherche et technologie

• Humans
• Parkinson Disease/complications
• Gait Disorders, Neurologic/complications
• Gait
• Walking Speed
• Postural Balance

• Jacques und Gloria Gossweiler-Stiftung

• ankle injury
• anticipatory postural adjustments
• center of pressure
• gait
• locomotion
• muscle activity

• Anticipatory postural adjustments
• Cerebral palsy
• Dynamic balance
• Measurement
• Next Step test
• Reliability

• Humans
• Child
• Cerebral Palsy
• Exercise Test
• Reproducibility of Results
• Postural Balance/physiology
• Movement/physiology

• ICA-CDRF-2017-03-041 Department of Health

• Adult
• Humans
• Male
• Foot
• Lower Extremity
• Motion
• Movement

• anticipatory postural adjustment
• cervical myelopathy
• cervical spondylotic myelopathy
• gait analysis
• ossification of the posterior longitudinal ligament

• motor control
• learning and memory

• Humans
• Walking/physiology
• Adaptation, Physiological/physiology
• Acclimatization
• Motivation
• Biomechanical Phenomena/physiology

• T32 EB009406 NIBIB NIH HHS
• National Institutes of Health
• McCormick School of Engineering, Northwestern University
• U.S. Department of Veterans Affairs

• Anticipatory postural adjustment
• Balance
• Cerebral palsy
• Stepping

• Age-related macular degeneration
• Human locomotion
• Mobility
• Postural control
• Time pressure
• Visual impairment

• anticipatory action planning
• go-before-you-know
• postural stability
• sensorimotor control
• stepping

• Japan Society for the Promotion of Science

• Developmental neurology & neurodisability
• Paediatric neurology
• REHABILITATION MEDICINE

• Adult
• Cerebral Palsy
• Child
• Exercise
• Feasibility Studies
• Humans
• Multicenter Studies as Topic
• Physical Therapy Modalities
• Randomized Controlled Trials as Topic
• Walking

Postural control precedes the goal-directed movement to maintain body equilibrium during the action. Because the environment continuously changes due to one’s activity, postural control requires a higher-order brain function that predicts the interaction between the body and the environment. Here, we tried to elucidate to what extent such a preceding postural control (PPC) predictively offered a posture that ensured the entire process of the goal-directed movement before starting the action. For this purpose, we employed three cats, which we trained to maintain a four-leg standing posture on force transducers to reach the target by either forelimb. Each cat performed the task under nine target locations in front with different directions and distances. As an index of posture, we employed the center of pressure (CVP) and examined CVP positions when the cat started postural alteration, began to lift its paw, and reached the target. After gazing at the target, each cat started PPC where postural alteration was accompanied by a 20–35 mm CVP shift to the opposite side of the forelimb to be lifted. Then, the cat lifted its paw at the predicted CVP position and reached the forelimb to the target with a CVP shift of only several mm. Moreover, each cat had an optimal target location where the relationship between the cat and target minimized the difference in the CVP positions between the predicted and the final. In this condition, more than 80% of the predicted CVP positions matched the final CVP positions, and the time requiring the reaching movement was the shortest. By contrast, the forelimb reaching movement required a greater CVP shift and longer time when the target was far from the cat. In addition, the time during forelimb reaching showed a negative correlation with the speed of the CVP shift during the PPC. These results suggest that the visuospatial information, such as the body-environment interaction, contributes to the motor programming of the PPC. We conclude that the PPC ensures postural stability throughout the action to optimize the subsequent goal-directed movements. Impairments in these processes may disturb postural stability during movements, resulting in falling.

• Japan Society for the Promotion of Science

Lateral stepping is a motor task that is widely used in everyday life to modify the base of support, change direction, and avoid obstacles. Anticipatory Postural Adjustments (APAs) are often analyzed to describe postural preparation prior to forward stepping, however, little is known about lateral stepping. The aim of the study is to characterize APAs preceding lateral steps and to investigate how these are affected by footwear and lower limb preference. Twenty-two healthy young participants performed a lateral step using both their preferred and non-preferred leg in both barefoot and shod conditions. APA spatiotemporal parameters (size, duration, and speed) along both the anteroposterior and mediolateral axes were obtained through force plate data. APAs preceding lateral stepping showed typical patterns both along the anteroposterior and mediolateral axis. RM-ANOVA highlighted a significant effect of footwear only on medio-lateral APAs amplitude (p = 0.008) and velocity (p = 0.037). No differences were found for the limb preference. APAs in lateral stepping presented consistent features in the sagittal component, regardless of limb/shoe factors. Interestingly, the study observed that footwear induced an increase in the medio-lateral APAs size and velocity, highlighting the importance of including this factor when studying lateral stepping.

• APA
• biomechanics
• footwear
• force plate
• laterality
• piezo-resistive sensors
• posture
• shoe
• step

• Parkinsonian disorders
• electromyography
• kinematic
• locomotion
• postural adjustments
• stiffness

This study aims to improve our understanding of gait initiation mechanisms and the lower-limb joint mechanical energy contributions. Healthy subjects were instructed to initiate gait on an instrumented track to reach three self-selected target velocities: slow, normal and fast. Lower-limb joint kinematics and kinetics of the first five strides were analyzed. The results show that the initial lateral weight shift is achieved by hip abduction torque on the lifting leg (leading limb). Before the take-off of the leading limb, the forward body movement is initiated by decreasing ankle plantarflexion torque, which results in an inverted pendulum-like passive forward fall. The hip flexion/extension joint has the greatest positive mechanical energy output in the first stride of the leading limb, while the ankle joint contributes the most positive mechanical energy in the first stride of the trailing limb (stance leg). Our results indicate a strong correlation between control of the frontal plane and the sagittal plane joints during gait initiation. The identified mechanisms and the related data can be used as a guideline for improving gait initiation with wearable robots such as exoskeletons and prostheses.

• anticipatory postural adjustment
• center of pressure
• motor control
• postural control
• speed-accuracy tradeoff

• cautious gait
• conscious movement processing
• inhibition
• older people
• reinvestment

• Anticipatory postural adjustments
• Balance
• Biomechanics
• Centre of pressure
• Gymnastics

• APA
• Forceplate
• Gait initiation
• Postural control
• Posture preparation

• Brain networks
• EEG
• Resting state

Older adults deemed to be at a high risk of falling will often display visual search behaviors likely to impair movement planning when negotiating environmental hazards. It has been proposed that these behaviors may be underpinned by fall-related anxiety. Thus, the aim of this study was to explore the effects of fall-related anxiety on visual search and stepping behaviors during adaptive gait.

Forty-four community-dwelling older adults (mean age = 74.61; standard deviation = 6.83) walked along a path and stepped into two raised targets. All participants completed walks at ground level, whereas participants deemed to be at a low risk of falling (n = 24) also completed walks under conditions designed to induce fall-related anxiety (walkway elevated 0.6 m). Participants’ movement kinematics and gaze behavior were measured.

During ground trials, “high-risk” participants visually prioritized the immediate walkway areas 1–2 steps ahead, at the expense of previewing future stepping constraints. This reduced planning appeared to negatively affect safety, with greater stepping errors observed for future constraints. When completing walks on the elevated walkway, “low-risk” participants similarly prioritized immediate walkway areas, at the expense of planning future stepping actions. These behaviors were associated with greater attention directed toward consciously processing walking movements.

These findings provide evidence of a link between heightened fall-related anxiety and “high-risk” visual search behaviors associated with greater stepping errors. This information enhances our understanding of why high-risk older adults are less able to safely navigate environmental constraints.

• Attention
• Eye tracking
• Falls
• Fear of falling
• Gait

• Early ambulation
• Gait-initiation
• Rehabilitation research
• Sit-to-stand
• Sit-to-walk
• Systematic review

• Balance
• Margin of stability
• Motor performance
• Obese
• Postural stability

• Biomechanical Phenomena
• Foot
• Gait
• Humans
• Obesity
• Postural Balance

An age-related decline in anticipatory postural mechanisms has been reported during gait initiation; however, it is unclear whether such decline may jeopardize whole-body stability following unexpected balance perturbations. This study aimed to compare young and older individuals’ ability to generate postural responses and preserve stability in response to external waist perturbations delivered within gait initiation.

Ten young and ten older participants performed 10 gait initiation trials followed by 48 unperturbed and 12 perturbed trials in a random order. A stereophotogrammetric system and three force platforms were used to quantify mechanical parameters from the preparatory phase (e.g., timing and amplitude of postural adjustments) and from the stepping phase (e.g., step characteristics and dynamic stability). Activation patterns of lower leg muscles were determined by surface electromyography.

Older participants responded to perturbation with lower increase in both magnitude (p < 0.001; η²_p = 0.62) and duration (p = 0.001; η²_p = 0.39) of preparatory parameters and soleus muscle activity (p < 0.001; η²_p = 0.55), causing shorter (p < 0.001; η²_p = 0.59) and lower (p < 0.001; η²_p = 0.43) stepping, compared to young participants. Interestingly, young participants showed greater correlations between preparatory phase parameters and dynamic stability of the first step than older participants (average r of − 0.40 and − 0.06, respectively).

The results suggest that young participants took more time than older to adjust the anticipatory biomechanical response to perturbation attempting to preserve balance during stepping. In contrast, older adults were unable to modify their anticipatory adjustments in response to perturbation and mainly relied on compensatory mechanisms attempting to preserve stability via a more cautious stepping strategy.

• Elderly
• Electromyography
• Fall risk
• Locomotion
• Posture
• Spatiotemporal analysis

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.

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.

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.

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.

• Correction
• Elderly
• Force
• Leg adjustments
• Target jump

• anticipatory postural adjustment (APA)
• center of mass (COM)
• center of pressure (COP)
• electromyography (EMG)
• gait initiation
• multidirectional steps

• Lissajous method
• Motor Control
• Simultaneous postural adjustments
• Single step

• balance
• ballet
• center of mass
• center of pressure
• inclination angle
• posture

• Angular momentum
• Balance
• Biomechanics
• Elderly
• Step initiation

• Adolescent
• Adult
• Aged
• Aging/physiology
• Biomechanical Phenomena/physiology
• Gait/physiology
• Healthy Volunteers
• Humans
• Middle Aged
• Postural Balance/physiology
• Walking/physiology
• Young Adult

• anticipatory postural adjustment (APA)
• elderly
• gait initiation
• whole-body vibration (WBV)
• young adults

• Adaptation
• Gait
• Internal model
• Motor control

Previous studies have reported that anticipatory postural adjustments (APAs) associated with gait initiation are affected by emotion-eliciting images. This study examined the effect of the duration of exposure to emotional images on the APAs along the progression axis. From a standing posture, 39 young adults had to reach a table by walking (several steps) toward pleasant or unpleasant images, under two sets of conditions. In the short condition, the word “go” appeared on the image 500 ms after image onset and participants were instructed to initiate gait as soon as possible after the word go appeared. In the long condition, the same procedure was used but the word “go” appeared 3000 ms after image onset. Results demonstrated that the APAs were longer and larger for pleasant images than unpleasant ones, regardless of the condition (i.e., the duration of exposure to the images). In the same way, the peak of forward velocity of the centre of body mass (reached at the end of the first step) followed the same tendency. These results emphasized that APAs depended on image valence but not on the duration of images exposure and were consistent with those of previous studies and the motivational direction hypothesis.

• anticipatory postural adjustments
• duration of images exposure
• emotion
• gait initiation

• balance
• coordination
• cortical
• gait initiation
• predictive control
• step adjustments
• stepping
• subcortical
• visual control

• ataxia
• balance
• cerebellar
• gait
• posture
• tremor

• balance stability
• external perturbations
• health and disease
• internal perturbations
• postural orientation
• sensorimotor control

• Anticipatory postural adjustments
• Balance control
• Biomechanics
• Dynamic stability
• Foot placement
• Foot strike pattern
• Gait initiation
• Lateral ankle strategy
• Leg stiffness
• Vertical center of mass braking

Rigid ankle-foot orthoses (AFO) are commonly used for impeding foot drop during the swing phase of gait. They also reduce pain and improve gait kinematics in patients with weakness or loss of integrity of ankle-foot complex structures due to various pathological conditions. However, this comes at the price of constraining ankle joint mobility, which might affect propulsive force generation and balance control. The present study examined the effects of wearing an AFO on biomechanical variables and electromyographic activity of tibialis anterior (TA) and soleus muscles during gait initiation (GI). Nineteen healthy adults participated in the study. They initiated gait at a self-paced speed with no ankle constraint as well as wearing an AFO on the stance leg, or bilaterally. Constraining the stance leg ankle decreased TA activity ipsilaterally during the anticipatory postural adjustment (APA) of GI, and ipsilateral soleus activity during step execution. In the sagittal plane, the decrease in the stance leg TA activity reduced the backward displacement of the center of pressure (CoP) resulting in a reduction of the forward velocity of the center of mass (CoM) measured at foot contact (FC). In the frontal plane, wearing the AFO reduced the displacement of the CoP in the direction of the swing leg during the APA phase. The mediolateral velocity of the CoM increased during single-stance prompting a larger step width to recover balance. During step execution, the CoM vertical downward velocity is normally reduced in order to lessen the impact of the swing leg with the floor and facilitates the rise of the CoM that occurs during the subsequent double-support phase. The reduction in stance leg soleus activity caused by constraining the ankle weakened the vertical braking of the CoM during step execution. This caused the absolute instantaneous vertical velocity of the CoM at FC to be greater in the constrained conditions with respect to the control condition. From a rehabilitation perspective, passively- or actively-powered assistive AFOs could correct for the reduction in muscle activity and enhance balance control during GI of patients.

• ankle rigidity
• ankle-foot orthosis
• balance control
• gait initiation
• vertical braking

• anticipatory postural adjustments
• balance
• external load
• gait initiation
• margin of stability
• postural stability
• weight bearing asymmetry

• Energy
• Gait
• Maneuver
• Margin of stability
• Work

• Adult
• Biomechanical Phenomena
• Foot/physiology
• Gait
• Humans
• Male
• Patient Positioning
• Postural Balance
• Reference Values
• Walking

• IK2 RX000717 RRD VA

• central pattern generation
• feed-forward control
• spinal automaticity
• spinal cord injury
• spinal learning

• Gait
• Movement patterns
• Segmental angular momentum