Biology subjects

van Dieen, J. H.

Publications and source records attributed to van Dieen, J. H..

At least 19 recordsLinked to original sources

bioRxiv2026

Cortico-muscular control of postural balance in older adults - effects of training on functional connectivity

BackgroundBalance training in older adults can lead to reduced centre of mass accelerations and reduced angular momenta after perturbations of unipedal stance, reflecting an enhanced ability to recover balance. It has been suggested that the co-occurring changes in muscle synergies indicated strategy-specific adaptations in feedback control. MethodsWe investigated the cortical involvement in such adaptations by focusing on the interaction between muscle synergies and cortical activity after perturbations. Twenty older adults (>65 years) underwent short-term and three-week long-term balance training, and we assessed their recovery from unpredictable mediolateral perturbations during unipedal stance. We measured high-density EEG and activation of leg and trunk muscles. The representations of the balance-related muscle synergies were localised in the cortex using coherence-based beamformers in the {beta}-frequency band. ResultsBalance performance was accompanied by task-specific {beta}-band activation in the somatotopic representation of the lower extremities in the primary motor cortex. The {beta}-power significantly dropped during the response to perturbations, while the coherence with the activation of muscle synergies significantly increased, especially for synergies active in the early stage of balance recovery. The task-related changes in cortico-synergy coherence, especially during the later phase of balance recovery, were significantly affected by short-term training. ConclusionRefinements of feedback control seem to underlie balance improvements in older adults. The significant changes in the cortico-synergy interaction after balance training suggest cortical involvement in these refinements.

neuroscience↗

bioRxiv2025

Shared feedback control principles across standing and walking

Intrinsic mechanisms and feedback control act together to stabilize the body in upright tasks. In unperturbed standing and walking, their combined effects can be captured by lumped stabilization models, relating delayed center of mass position and velocity information to current ground reaction forces. If and how lumped stabilization parameters change across these tasks is unclear. We applied a stabilization model to estimate and compare stabilization between unperturbed standing and walking. Fifteen healthy young participants (21+/- 4 yrs, 63 +/- 9 kg, 1.70 +/-0.10 m, 13 females, 2 males) walked at 1.25 m/s for 5 minutes, and performed 3 different standing tasks: normal standing, unipedal standing, and step posture for 1 minute, repeated 5 times. Whole-body kinematics and ground reaction forces were collected and used to fit the stabilization model and estimate the effective delay and lumped gains. Only small differences were found between standing tasks. Model fits were significantly higher in standing than in walking. ML effective delays were significantly longer in walking than in standing, whereas AP delays were comparable. The stabilization gains varied significantly across tasks and directions. The lumped position gains in most tasks exceeded critical stiffness, except for the mean values in walking, which were lower than the critical stiffness. Lumped velocity gains were all at under-damped level. The ratio of lumped position to velocity gains in standing were consistently close to human body's eigenfrequency (sqrt(g/l)) as predicted by the extrapolated center of mass concept. In walking, the ratio was close to the eigenfrequency during phases in which stabilization was significant. Our findings suggest that stabilization is organized at the task level, with lumped effects of all stabilizing mechanisms acting to preserve a consistent weighting between position and velocity contributions across tasks, effectively regulating the CoM motion to follow a pendulum-like trajectory.

neuroscience↗

bioRxiv2025

How do we tread? Differences in stability-related foot placement control between overground and treadmill walking in young adults

Step-by-step foot placement control, accommodating for natural variations in center-of-mass state, ensures stability during steady-state gait. Current understanding of this foot placement mechanisms is primarily based on findings during treadmill walking. However, contextual differences might hamper generalization of these findings towards overground walking, and ultimately daily life gait. This study investigated whether foot placement control manifests itself differently during overground as compared to treadmill walking in healthy young adults. 14 young adults walked at comfortable walking speed, both on the treadmill and overground in a figure-8 path. During overground walking we found a significant relationship between the step width/step length and the center-of-mass state during the swing phase of walking, capturing foot placement control with the same linear model as during treadmill walking. Contrary to what was hypothesized, we found a significant lower foot placement precision during overground walking for the step width model with center-of-mass state at the start of the swing phase as predictor, complemented by a wider average step width. Moreover, during overground walking participants responded less strongly to a deviation in center-of-mass position, yet significantly stronger to deviations in center-of-mass velocity at the end of the step for both the step width/step length models. Exploratory analysis showed a larger relative contribution of velocity feedback during over ground walking as compared to treadmill walking. These differences warrant caution in generalizing foot placement findings during treadmill walking to overground walking and might be promising for the estimation of foot placement control in daily life gait.

physiology↗

bioRxiv2025

Foot placement coordination is impaired in people with Parkinson's Disease

BackgroundGait instability is a common and disabling symptom of Parkinsons disease (PD), contributing to frequent falls and reduced quality of life. While clinical balance tests and spatiotemporal gait measures can predict fall risk, they do not fully explain the underlying control mechanisms. In healthy individuals, foot placement is actively adjusted based on an internal estimate of the center of mass state to maintain gait stability, known as foot placement control. This estimation relies on the integration of multisensory information, which has been shown to be impaired in PD, potentially disrupting the control of gait stability through foot placement. ObjectiveTo investigate whether foot placement coordination during overground walking is impaired in people with PD. MethodsFifty people with PD and 51 healthy older adults walked overground for ten minutes at self-selected, comfortable walking speed. Foot placement errors were quantified as the deviation between the actual foot placement and the predicted placement derived from the center of mass kinematic state during the preceding swing phase. ResultsFoot placement errors were significantly higher in people with PD than in healthy older adults in both mediolateral (p < .05) and anteroposterior directions (p < .0001), at both mid-swing and terminal swing. Relative explained variance in mediolateral direction was significantly higher in people with PD compared to healthy older adults (p < .005). ConclusionWe provide first evidence of impaired coordination between the center of mass and foot placement in PD. Future work should investigate a causal relationship between impaired foot placement control, sensorimotor integration and gait instability.

pathology↗

bioRxiv2025

The contribution of vestibular and proprioceptive signals to trunk stabilization varies between postural tasks and between walking speeds.

Stabilizing the upright posture of the trunk relies on vestibular and proprioceptive afference. Previous studies found that the feedback responses to sensory afference vary between postures and tasks. We investigated whether and how vestibular and proprioceptive afference contribute to trunk stabilization during different postural tasks, and during walking at different speeds. Twelve healthy adults performed tasks in a random order: sitting, standing on the right foot or both feet, and treadmill walking at five speeds: 0.8, 2.0, 3.2, 4.3 and 5.5 km/h, while exposed to unilateral muscle vibration on the right paraspinal muscles at the level of the second lumbar vertebra, or to a step-like electrical vestibular stimulation (EVS) with the anode behind the left ear. The mediolateral displacements of markers at the sixth thoracic level and sacrum in the global coordinate system were used to evaluate the responses to sensory stimulation. No significant responses to EVS at T6 and sacrum level were found in sitting and standing. Responses to muscle vibration were significant and differed between unipedal standing compared to sitting and bipedal standing. The latter suggests a different interpretation of the sensation of muscle lengthening in these postures. During walking, the magnitude of the responses to both stimuli increased from very slow speeds to moderate speeds. From moderate to higher speeds, responses to muscle vibration decreased, whereas responses to EVS plateaued. These findings suggest speed-dependent modulation of vestibular and proprioceptive contributions in trunk stabilization during walking. Summary statementBy applying electrical vestibular stimulation and muscle vibration, we found that how vestibular and proprioceptive signals are used for trunk stabilization differs between postural tasks and walking speeds.

neuroscience↗

bioRxiv2025

The Impact of Visual Perturbations on Balance Control during Walking

Visual perturbations may lead to an illusory self-motion and affect balance control. We studied effects of different visual perturbations in 16 healthy young participants walking on a treadmill, by assessing foot placement and center of mass (CoM) states. Three different visual perturbations were applied: fixating on a stationary target while the background moved to the right (MB), tracking the target moving rightward over a stationary background with head rotation (MT-HR), and tracking the moving target with eye movement only (MT-EM). Deviations of foot placement, CoM and trunk orientation due to the visual perturbation were assessed. Linear models were fit to the kinematic data to predict foot placement from CoM state at mid-swing. Over the whole trial, MT-HR and MT-EM caused an increase in step width variability, CoM position variability and RMS of foot placement errors simultaneously. During visual perturbation epochs specifically, in MB, a left deviation of foot and CoM trajectories was observed from the start of the background movement. In MT-HR and MT-EM, a right deviation of foot and CoM trajectories was observed only after the target had stopped moving. Contrary to our expectations, foot placement errors did not coincide with subsequent CoM deviations in the opposite direction. An obvious change in frontal plane trunk orientation was found only in MT-HR. While all visual perturbations affected control of the CoM trajectory in the frontal plane, these effects appeared caused by effects on control of heading as well. Head rotation appears to additionally disturb balance through a coupling with trunk orientation. Summary statementVisual perturbations during walking alter foot placement and body motion in humans, revealing how eye and head movements influence walking balance.

neuroscience↗

bioRxiv2025

Simultaneous stabilizing feedback control of linear and angular momentum in human walking

Stabilizing bipedal gait is mechanically challenging. To analyze how gait is stabilized, previous studies have focused on the control of the body center of mass (CoM). These studies often linked deviations in linear momentum of the CoM to subsequent shifts in position of the center of pressure (CoP), or of the foot, relative to the COM, and interpreted these as stabilizing responses to correct linear CoM momentum. Mechanically, however, CoP shifts do not cause changes of linear CoM momentum, whereas they do cause changes in whole-body angular momentum. We hypothesized that experimentally observed correlations between CoP to CoM distance and horizontal ground reaction forces are related to the need to control both linear and whole-body angular momentum. We show that, in human walking, linear and angular momentum follow quasi-periodic functions with similar periodicity and phase. Combining the equations of linear and rotational motion for a system of linked rigid segments shows that, in this case, the horizontal distance between CoP and CoM should be correlated to horizontal force in the corresponding direction. This suggests that linear and angular momentum are simultaneously controlled and may explain the success of preceding studies that correlated CoM states to CoP or foot locations. Regression models fitted to experimental data of participants walking at normal and slow speeds showed that deviations in horizontal ground reaction forces and in moments of the ground reaction force about the sagittal and transverse axes could be predicted from deviations in the preceding linear and angular momentum respectively. Our analyses support that linear and angular momentum are indeed controlled simultaneously in human walking.

biophysics↗

bioRxiv2024

The effect of head orientation on vestibular signal-based modulation of paraspinal muscle activity during walking

Vestibulospinal reflexes play a role in maintaining the upright posture of the trunk. Head orientation has been shown to modify the vestibulospinal reflexes during standing. This study investigated how vestibular signals affect paraspinal muscle activity during walking, and whether head orientation changes these effects. Sixteen participants were instructed to walk on a treadmill for 8 min at 78 steps/min and 2.8 km/h in four conditions defined by the presence of electrical vestibular stimulation (EVS) and by head orientation (facing forward and facing leftward), while bipolar electromyography (EMG) was recorded bilaterally from the paraspinal muscles from cervical to lumbar levels. In both head orientations, significant phasic EVS-EMG coherence (p < 0.01) in the paraspinal muscles was observed at ipsilateral and/or contralateral heel strikes. Compared to walking with the head forward, a significant decrease (p < 0.05) was found in EVS evoked responses (i.e., EVS-EMG coherence and gain) when participants walked with the leftward head orientation, with which EVS induced disturbance in the sagittal plane. This overall decrease may be explained by less need of feedback control for walking stabilization in the sagittal plane compared to in the frontal plane. The decrease in coherence was only significant at the left lower vertebral levels and at the right upper vertebral levels around left heel strikes (p < 0.05). Together, these findings confirm the contribution of the vestibular afferent signals to the control of paraspinal muscle activity during walking and indicate that this control is changed in response to different head orientations. Key Point SummaryO_LIVestibulospinal reflexes simultaneously contribute to stabilizing the centre of mass trajectory and to maintaining an upright posture of the trunk. C_LIO_LIHead orientation, which challenges stability via altered visual, vestibular and proprioceptive signals, modifies vestibulospinal reflexes during standing. C_LIO_LITo explore the impact of head orientation during walking, we recorded bilateral surface EMG of cervical to lumbar paraspinal muscles, and characterized coherence, gain and delay between EMG and electrical vestibular stimulation, during walking with head facing forward and leftward. C_LIO_LIWhen walking with head facing leftward, vestibular stimulation caused disturbance in sagittal plane. Phasic response in paraspinal muscles with a significant smaller magnitude was found compared to facing forward. C_LIO_LIOur results agree with the idea that less feedback control is required for walking stabilization in the sagittal plane and confirm that vestibular afference modulates paraspinal muscle activity for trunk control during walking, and this modulation is changed in response to head orientation. C_LI

physiology↗

bioRxiv2023

Vertebral level specific modulation of paraspinal muscle activity based on vestibular signals during walking.

Evoking muscle responses by electrical vestibular stimulation (EVS) may help to understand the contribution of the vestibular system to postural control. Although paraspinal muscles play a role in postural stability, the vestibulo-muscular coupling of these muscles during walking has rarely been studied. This study aimed to investigate how vestibular signals affect paraspinal muscle activity at different vertebral levels during walking with preferred and narrow step width. Sixteen healthy participants were recruited. Participants walked on a treadmill for 8 minutes at 78 steps/min and 2.8 km/h, at two different step width, either with or without EVS. Bipolar electromyography was recorded bilaterally from the paraspinal muscles at eight vertebral levels from cervical to lumbar. Coherence, gain, and delay of EVS and EMG responses were determined. Significant EVS-EMG coupling (p<0.01) was found at ipsilateral and/or contralateral heel strikes. This coupling was mirrored between left and right relative to the midline of the trunk and between the higher and lower vertebral levels, i.e., a peak occurred at ipsilateral heel strike at lower levels, whereas it occurred at contralateral heel strike at higher levels. EVS-EMG coupling only partially coincided with peak muscle activity. EVS-EMG coherence slightly, but not significantly, increased when walking with narrow steps. No significant differences were found in gain and phase between the vertebral levels or step width conditions. In summary, vertebral level specific modulation of paraspinal muscle activity based on vestibular signals might allow a fast, synchronized, and spatially co-ordinated response along the trunk during walking. Key Points SummaryO_LIMediolateral stabilization of gait requires an estimate of the state of the body, which is affected by vestibular afference. C_LIO_LIDuring gait, the heavy trunk segment is controlled by phasic paraspinal muscle activity and in rodents the medial and lateral vestibulospinal tracts activate these muscles. C_LIO_LITo gain insight in vestibulospinal connections in humans and their role in gait, we recorded paraspinal surface EMG of cervical to lumbar paraspinal muscles, and characterized coherence, gain and delay between EMG and electrical vestibular stimulation, during slow walking. C_LIO_LIVestibular stimulation caused phasic, vertebral level specific modulation of paraspinal muscle activity at delays of around 40 milliseconds, which was mirrored between left, lower and right, upper vertebral levels. C_LIO_LIOur results indicate that vestibular afference causes fast, synchronized, and spatially co-ordinated responses of the paraspinal muscles along the trunk, that simultaneously contribute to stabilizing the centre of mass trajectory and to keeping the head upright. C_LI

physiology↗

bioRxiv2023

ASSESSMENT OF STABILIZING FEEDBACK CONTROL OF WALKING, A TUTORIAL

Walking without falling requires stabilization of the trajectory of the body center of mass relative to the base of support. Model studies suggest that this requires active, feedback control, i.e., the nervous system must process sensory information on the state of the body to generate descending motor commands to the muscles to stabilize walking, especially in the mediolateral direction. Stabilization of bipedal gait is challenging and can be impaired in older and diseased individuals. In this tutorial, we illustrate how gait analysis can be used to assess the stabilizing feedback control of gait. We present methods ranging from those that require limited input data (e.g. position data of markers placed on the feet and pelvis only) to those that require full-body kinematics and electromyography. Analyses range from simple kinematics analyses to inverse dynamics. These methods assess stabilizing feedback control of human walking at three levels: 1) the level of center of mass movement and horizontal ground reaction forces, 2) the level of center of mass movement and foot placement and 3) the level of center of mass movement and the joint moments or muscle activity. We show how these can be calculated and provide a GitHub repository (https://github.com/VU-HMS/Tutorial-stabilizing-walking) which contains open access Matlab and Python code to calculate these. Finally, we discuss what information on feedback control can be learned from each of these.

neuroscience↗

bioRxiv2023

Foot placement control can be trained: Older adults learn to walk more stable, when ankle moments are constrained

Falls are a problem, especially for older adults. Placing our feet accurately relative to the center-of-mass helps us to prevent falling during gait. The degree of foot placement control with respect to the center-of mass kinematic state is decreased in older as compared to young adults. Here, we attempted to train mediolateral foot placement control in healthy older adults. Ten older adults trained by walking on shoes with a narrow ridge underneath (LesSchuh), restricting mediolateral center-of-pressure shifts. As a training effect, we expected improved foot placement control during normal walking. A training session consisted of a normal walking condition, followed by a training condition on LesSchuh and finally an after-effect condition. Participants performed six of such training sessions, spread across three weeks. As a control, before the first training session, we included two similar sessions, but on normal shoes only. We evaluated whether a training effect was observed across sessions and weeks in a repeated-measures design. Whilst walking with LesSchuh, the magnitude of foot placement error reduced half-a-millimeter between sessions within a week (cohens d=0.394). As a training effect in normal walking, the magnitude of foot placement errors was significantly lower compared to the control week, by one millimeter in weeks 2 (cohens d=0.686) and 3 (cohens d=0.780) and by two millimeters in week 4 (cohens d=0.875). Local dynamic stability of normal walking also improved significantly. More precise foot placement may thus have led to improved stability. It remains to be determined whether the training effects were the result of walking on LesSchuh or from repeated treadmill walking itself. Moreover, enhancement of mechanisms beyond the scope of our outcome measures may have improved stability. At the retention test, gait stability returned to similar levels as in the control week. Yet, a reduction in foot placement error persisted.

biophysics↗

bioRxiv2022

Is phase-dependent stability related to phase-dependent gait robustness?

Predicting gait robustness is paramount for targeting interventions to prevent falls. Our analysis of a compass walker model revealed that phase-dependent stability measures have limited capacity to predict overall gait robustness. Interestingly, these measures vary substantially over the gait cycle which seemingly aligns with the robustness of both humans and walking models that likewise depends on the phase at which perturbations occur. To explore this in depth, we again used a compass walker model that can walk stably and periodically and applied forward and backward perturbations (instantaneous changes in angular velocities) to the stance or swing leg at multiple instants during the single-stance phase. We then estimated the degree to which phase-dependent stability measures correlate with phase-dependent gait robustness, quantified as the maximal perturbation-induced change in mechanical energy that the walker could tolerate without falling within 50 steps. We found that these phase-dependent stability measures did not adequately predict phase-dependent gait robustness in the compass walker model. We therefore conclude that these measures are unlikely to provide reliable predictions of gait robustness or fall risk in humans.

physiology↗

bioRxiv2022

The energetic effect of hip flexion and retraction in walking at different speeds: a modeling study

In human walking, power for propulsion is generated primarily via ankle and hip muscles. The addition of a passive hip spring to simple bipedal models appears more efficient than using only push-off impulse, at least, when hip spring associated energetic costs are not considered. Hip flexion and retraction torques, however, are not free, as they are produced by muscles demanding metabolic energy. Studies evaluating the inclusion of hip actuation costs, especially during the swing phase, and the hip actuations energetic benefits are few and far between. It is also unknown whether these possible benefits/effects may depend on speed. We simulated a planar flat-feet model walking stably over a range of speeds. We asked whether the addition of independent hip flexion and retraction remains energetically beneficial when considering work-based metabolic cost of transport (MCOT) with different efficiencies of doing positive and negative work. We found asymmetric hip actuation can reduce the estimated MCOT relative to ankle actuation by up to 6%, but only at medium speeds. The corresponding optimal strategy is zero hip flexion and some hip retraction actuation. The reason for this reduced MCOT is a reduction in collision loss being larger than the associated increase in hip negative work. Both terms require positive mechanical work to compensate, yielding a larger reduction in metabolic work per step than the reduction in step length. Our study shows how ankle actuation, hip flexion, and retraction actuation can be coordinated to reduce MCOT.

physiology↗

bioRxiv2022

The effect of external lateral stabilization on ankle moment control during steady-state walking

External lateral stabilization can help identify stability control mechanisms during steady-state walking. The degree of step-by-step foot placement control and step width are known to decrease when walking with external lateral stabilization. Here, we investigated the effect of external lateral stabilization on ankle moment control in healthy participants. Ankle moment control complements foot placement, by allowing a corrective center-of-pressure shift once the foot has been placed. This is reflected by a model predicting this center-of-pressure shift based on the preceding foot placement error. Here, the absolute explained variance accounted for by this model decreased when walking with external lateral stabilization. In other words, we found a reduction in the contribution of step-by-step ankle moment control to mediolateral gait stability when externally stabilized. Concurrently, foot placement error and the average center-of-pressure shift remained unchanged.

biophysics↗

bioRxiv2022

Does ankle push-off correct for errors in anterior-posterior foot placement relative to center-of-mass state?

I.Understanding the mechanisms humans use to stabilize walking is vital for predicting falls in elderly. Modeling studies identified two potential mechanisms to stabilize gait in the anterior-posterior direction: foot placement control and ankle push-off control: Foot placement depends on position and velocity of the center-of-mass (CoM) and push-off modulates with deviations between actual and predicted CoM trajectories. While both control mechanisms have been reported in humans, it is unknown whether especially the latter one is employed in unperturbed steady-state walking. On the one hand, the covariance between CoM states and anterior-posterior foot placement served as a measure of foot placement control. On the other hand, we determined variations in ankle push-off as a function of differences between the actual foot placement and the one predicted from CoM states. We estimated the corresponding correlations and consider them indictors for push-off control based on foot placement errors. We found ankle push-off torque to be correlated to the foot placement error in 30 participants when walking at normal and slow speed, with mean correlation values of up to 0.45. Our study suggests that humans use a push-off strategy for correcting foot placement errors in steady-state walking.

physiology↗

bioRxiv2021

Effects of vestibular stimulation on gait stability and variability

Vestibular information modulates muscle activity during gait, presumably to contribute to stability. If this is the case, stronger effects of perturbing vestibular information on local dynamic stability of gait, a measure of the locomotor systems response to small, naturally occurring perturbations, can be expected for narrow-base walking (which needs more control) than for normal walking and smaller effects for wide-base walking (which needs less control). An important mechanism to stabilize gait is to coordinate foot placement to center of mass (CoM) state. Vestibular information most likely contributes to sensing this CoM state. We, therefore, expected that stochastic electrical vestibular stimulation (EVS) would decrease the correlation between foot placement and CoM state during the preceding swing phase. In fourteen healthy participants, we measured the kinematics of the trunk (as a proxy of the CoM), and feet, while they walked on a treadmill in six conditions: control (usual step width), narrow-base, and wide-base, each with and without stochastic EVS (peak amplitude of 5 mA; RMS of ~ 1.2 mA; frequency band from 0 to 25 Hz). Stochastic EVS decreased local dynamic stability irrespective of step width. Foot placement correlated stronger with trunk motion during walking with EVS than without in the control condition. However, residual variance in foot placement was increased when walking with EVS, indicating less precise foot placement. Thus, a vestibular error signal leads to a decrease in gait stability and precision of foot placement but these effects are not consistently modulated by step width.

neuroscience↗

bioRxiv2021

The effect of external lateral stabilization on energy cost of walking - A systematic review and meta-analysis

Previous studies have estimated the energy cost required for the control of medio-lateral stability in human walking by means of external lateral stabilization. Results were inconsistent, possibly due to differences in task constraints or stabilization devices. To better understand the effects of lateral stabilization on energy cost, we conducted a systematic review with meta-analysis of studies, which directly assessed effects of lateral stabilization on energy cost in healthy young adult participants (18-41 years old). We obtained individual participant data on net energy cost (J kg-1 m-1) from previously published studies. Across all studies reviewed, the net energy cost reduction during stabilized walking at preferred and zero step widths equaled to 0.05 {+/-} 0.35 (~2-3% reduction) and 0.25 {+/-} 0.29 J kg-1 m-1 (mean {+/-} s.d.) (~8-9% reduction), respectively. The effect of external lateral stabilization was significant only for walking at zero step width and without arm swing. Lateral stabilization devices with short rope length increased energy cost reduction. However, spring stiffness and habituation time did not influence energy cost reduction. We provide recommendations for improvement of lateral stabilization devices to avoid some of the confounding effects. External lateral stabilization reduces energy cost during walking by a small amount. It can be concluded that a small proportion of total energy cost is required to control medio-lateral stability; this proportion is larger when walking with narrow steps and without arm swing.

physiology↗

bioRxiv2021

Can foot placement during gait be trained? Adaptations in stability control when ankle moments are constrained

Accurate coordination of mediolateral foot placement, relative to the center of mass kinematic state, is one of the mechanisms which ensures mediolateral stability during human walking. Previously, we found that shoes constraining ankle moments decreased the degree of foot placement control with respect to the center of mass kinematic state. As such, ankle moment constraints can be seen as a perturbation of foot placement. Direct mechanical perturbations of the swing leg trajectory can improve the degree of foot placement control as an after-effect. Here, we asked whether constrained ankle moments could have a similar effect. If confirmed, this would offer a simple training tool for individuals with impaired foot placement control. Participants walked in three conditions; normal (baseline) while wearing shoes constraining ankle moments (training) and normal again (after-effects). The degree of foot placement control was calculated as the percentage of variance in foot placement that could be predicted based on the center of mass kinematic state in the preceding swing phase. During training, the degree of foot placement control decreased initially compared to baseline, but it gradually improved over time. In the after-effect condition, it was higher than during baseline, yet not significantly so. During training, we observed increased step width, decreased stride time and reduced local dynamic stability. In conclusion, constraining ankle moment control deteriorates the degree of foot placement control. A non-significant trend towards an improved degree of foot placement control after prolonged exposure to constrained ankle moments, allows for speculation on a training potential.

biophysics↗