Biomechanics Commons^™

Step Activity And 6-Minute Walk Test Outcomes When Wearing Low-Activity Or High-Activity Prosthetic Feet, Shane Wurdeman, Kendra K. Schmid, Sara A. Myers, Adam L. Jacobsen, Nicholas Stergiou

Journal Articles

Objective

To determine changes in average daily step count (ADSC) and 6-minute walk test (6MWT) due to use of low-activity feet (LA) and high-activity energy-storage-and-return (ESAR) feet, and examine the sensitivity of these measures to properly classify different prosthetic feet.

Design

Individuals with transtibial amputations (n = 28) participated in a 6-week, randomized crossover study. During separate 3-week periods, participants wore either a LA foot (eg, solid-ankle-cushioned-heel) or an ESAR foot. Differences in 6MWT and ADSC at the end of the 3-week period were recorded.

Results

Subjects performed similarly in the 6MWT with the LA and ESAR foot (P …

Reducing The Metabolic Cost Of Walking With An Ankle Exoskeleton: Interaction Between Actuation Timing And Power, Samuel Galle, Philippe Malcolm, Steven Hartley Collins, Dirk De Clercq

Journal Articles

Background

Powered ankle-foot exoskeletons can reduce the metabolic cost of human walking to below normal levels, but optimal assistance properties remain unclear. The purpose of this study was to test the effects of different assistance timing and power characteristics in an experiment with a tethered ankle-foot exoskeleton.

Methods

Ten healthy female subjects walked on a treadmill with bilateral ankle-foot exoskeletons in 10 different assistance conditions. Artificial pneumatic muscles assisted plantarflexion during ankle push-off using one of four actuation onset timings (36, 42, 48 and 54% of the stride) and three power levels (average positive exoskeleton power over a stride, summed …

Children With Moderate To Severe Cerebral Palsy May Not Benefit From Stochastic Vibration When Developing Independent Sitting, Anastasia Kyvelidou, Regina T. Harbourne, Joshua L. Haworth, Kendra K. Schmid, Nicholas Stergiou

Journal Articles

Purpose: Determine sitting postural control changes for children with cerebral palsy (CP), using a perceptual-motor intervention and the same intervention plus stochastic vibration through the sitting surface. Methods: Two groups of children with moderate or severe CP participated in the 12 week interventions. The primary outcome measure was center of pressure data from which linear and nonlinear variables were extracted and the gross motor function measure (GMFM). Results: There were no significant main effects of intervention or time or an interaction. Both treatment groups increased the Lyapunov exponent values in the medial–lateral direction three months after the …

Walking To A Multisensory Beat, Charlotte Roy, Julien Lagarde, Dobromir Dotov, Simone Dalla Bella

Journal Articles

Living in a complex and multisensory environment demands constant interaction between perception and action. In everyday life it is common to combine efficiently simultaneous signals coming from different modalities. There is evidence of a multisensory benefit in a variety of laboratory tasks (temporal judgement, reaction time tasks). It is less clear if this effect extends to ecological tasks, such as walking. Furthermore, benefits of multimodal stimulation are linked to temporal properties such as the temporal window of integration and temporal recalibration. These properties have been examined in tasks involving single, non-repeating stimulus presentations. Here we investigate the same temporal properties …

Mastoid Vibration Affects Dynamic Postural Control During Gait In Healthy Older Adults, Jung Hung Chien, Mukul Mukherjee, Jenny Kent, Nick Stergiou

Journal Articles

Vestibular disorders are difficult to diagnose early due to the lack of a systematic assessment. Our previous work has developed a reliable experimental design and the result shows promising results that vestibular sensory input while walking could be affected through mastoid vibration (MV) and changes are in the direction of motion. In the present paper, we wanted to extend this work to older adults and investigate how manipulating sensory input through mastoid vibration (MV) could affect dynamic postural control during walking. Three levels of MV (none, unilateral, and bilateral) applied via vibrating elements placed on the mastoid processes were combined …

Cognitive And Movement Measures Reflect The Transition To Presence-At-Hand, Dobromir Dotov, Lin Nie, Kevin Wojcik, Anastasia Jinks, Xiaoyu Yu, Anthony Chemero

Journal Articles

The phenomenological philosopher Martin Heidegger's proposed transition from readiness-to-hand to presence-at-hand and the hypothesis of extended cognition were addressed empirically in an experiment on tool use. It involved a video game of steering erratically moving objects to a target while performing a secondary cognitive task. A strong perturbation of the hand-pointer linkage in the video game induced the transition from ready-to-hand to present-at-hand. In Experiment 1, this perturbation resulted in decreased motor performance and improved recall of task-irrelevant features. Experiment 2 replicated these results and addressed additional questions. Measures of movement variability based on the multifractal formalism confirmed the …

Continuous Sweep Versus Discrete Step Protocols For Studying Effects Of Wearable Robot Assistance Magnitude, Philippe Malcolm, Denise Martineli Rossi, Christopher Siviy, Sangjun Lee, Brendan Thomas Quinlivan, Martin Grimmer, Conor J. Walsh

Journal Articles

Background: Different groups developed wearable robots for walking assistance, but there is still a need for methods to quickly tune actuation parameters for each robot and population or sometimes even for individual users. Protocols where parameters are held constant for multiple minutes have traditionally been used for evaluating responses to parameter changes such as metabolic rate or walking symmetry. However, these discrete protocols are time-consuming. Recently, protocols have been proposed where a parameter is changed in a continuous way. The aim of the present study was to compare effects of continuously varying assistance magnitude with a soft exosuit against …

The Rim And The Ancient Mariner: The Nautical Horizon Affects Postural Sway In Older Adults, Justin Munafo, Michael G. Wade, Nick Stergiou, Thomas A. Stoffregen

Journal Articles

On land, the spatial magnitude of postural sway (i.e., the amount of sway) tends to be greater when participants look at the horizon than when they look at nearby targets. By contrast, on ships at sea, the spatial magnitude of postural sway in young adults has been greater when looking at nearby targets and less when looking at the horizon. Healthy aging is associated with changes in the movement patterns of the standing body sway, and these changes typically are interpreted in terms of age-related declines in the ability to control posture. To further elucidate the mechanisms associated with these …

Chapter 9: Biomechanics, Nicholas Stergiou, Daniel Blanke, Sara A. Myers, Ka-Chun Siu

Journal Articles

Biomechanics is a discipline. A discipline deals with understanding, predicting, and explaining phenomena within a content domain, and biomechanics is the study of the human body in motion. By applying

principles from mechanics and engineering, biomechanists are able to study the forces that act on the body and the effects they produce (Bates, 1991). Hay (1973) describes biomechanics as the science that examines forces acting on and within a biological structure and the effects produced by such forces, whereas Alt (1967) describes biomechanics as the science that investigates the effect of internal and external forces on human and animal bodies …

Time-Series Analysis Of Embodied Interaction: Movement Variability And Complexity Matching As Dyadic Properties, Leonardo Zapata-Fonseca, Dobromir Dotov, Ruben Fossion, Tom Froese

Journal Articles

There is a growing consensus that a fuller understanding of social cognition depends on more systematic studies of real-time social interaction. Such studies require methods that can deal with the complex dynamics taking place at multiple interdependent temporal and spatial scales, spanning sub-personal, personal, and dyadic levels of analysis. We demonstrate the value of adopting an extended multi-scale approach by re-analyzing movement time-series generated in a study of embodied dyadic interaction in a minimal virtual reality environment (a perceptual crossing experiment). Reduced movement variability revealed an interdependence between social awareness and social coordination that cannot be accounted for by either …

Indifference To Chaotic Motion May Be Related To Social Disinterest In Children With Autism, Joshua L. Haworth, Anastasia Kyvelidou, Wayne Fisher, Nicholas Stergiou

Journal Articles

Children with autism spectrum disorder tend to have little interest in the presence, actions, and motives of other persons. In addition, these children tend to present with a limited and overly redundant movement repertoire, often expressing hyperfixation and aversion to novelty. We explore whether this is related to a more fundamental lack of appreciation for various temporal dynamics, including periodic, chaotic, and aperiodic motion structures. Seven children with ASD (age, gender, and height matched with children without ASD) were asked to stand and watch the motion of a visual stimulus displayed on a large (55") video monitor. Gaze and posture …

Dynamic Perception Of Dynamic Affordances: Walking On A Ship At Sea, Hannah Walter, Jeffrey B. Wagman, Nicholas Stergiou, Nurtekin Erkmen, Thomas A. Stoffregen

Journal Articles

Motion of the surface of the sea (waves, and swell) causes oscillatory motion of ships at sea. Generally, ships are longer than they are wide. One consequence of this structural difference is that oscillatory ship motion typically will be greater in roll (i.e., the ship rolling from side to side) than in pitch (i.e., the bow and stern rising and falling). For persons on ships at sea, affordances for walking on the open deck should be differentially influenced by ship motion in roll and pitch. Specifically, the minimum width of a walkable path should be greater when walking along the …

Hallux Valgus Surgery Affects Kinematic Parameters During Gait, Jitka Klugarova, Miroslav Janura, Zdenek Svoboda, Zdenek Sos, Nicholas Stergiou, Miloslav Klugar

Journal Articles

Background

The aim of our study was to compare spatiotemporal parameters and lower limb and pelvis kinematics during the walking in patients with hallux valgus before and after surgery and in relation to a control group.

Methods

Seventeen females with hallux valgus, who underwent first metatarsal osteotomy, constituted our experimental group. The control group consisted of thirteen females. Kinematic data during walking were obtained using the Vicon MX system.

Findings

Our results showed that hallux valgus before surgery affects spatiotemporal parameters and lower limb and pelvis kinematics during walking. Hallux valgus surgery further increased the differences that were present before …

Speed And Rhythm Affect Temporal Structure Of Variability In Reaching Poststroke: A Pilot Study, Amit Sethi, Nicholas Stergiou, Tara Patterson, Carolynn Patten, Lorie G. Richards

Journal Articles

Temporal structure reveals the potential adaptive strategies employed during upper extremity movements. The authors compared the temporal structure of upper extremity joints under 3 different reaching conditions: preferred speed, fast speed, and reaching with rhythmic auditory cues in 10 individuals poststroke. They also investigated the temporal structure of these 3 reaching conditions in 8 healthy controls to aid in the interpretation of the observed patterns in the poststroke cohort. Approximate entropy (ApEn) was used to measure the temporal structure of the upper extremity joints. ApEn was similar between conditions in controls. After stroke, ApEn was significantly higher for shoulder, elbow, …

Biologically-Variable Rhythmic Auditory Cues Are Superior To Isochronous Cues In Fostering Natural Gait Variability In Parkinson’S Disease, Dobromir Dotov, S. Bayard, Valérie Cochen De Cock, Christian Geny, Valérie Driss, G. Garrigue, Benoit G. Bardy, Simone Dalla Bella

Journal Articles

Introduction

Method

Effect Of Timing Of Hip Extension Assistance During Loaded Walking With A Soft Exosuit, Ye Ding, Fausto A. Panizzolo, Christopher Siviy, Philippe Malcolm, Ignacio Galiana, Kenneth G. Holt, Conor J. Walsh

Journal Articles

Background

Recent advances in wearable robotic devices have demonstrated the ability to reduce the metabolic cost of walking by assisting the ankle joint. To achieve greater gains in the future it will be important to determine optimal actuation parameters and explore the effect of assisting other joints. The aim of the present work is to investigate how the timing of hip extension assistance affects the positive mechanical power delivered by an exosuit and its effect on biological joint power and metabolic cost during loaded walking. In this study, we evaluated 4 different hip assistive profiles with different actuation timings: early-start-early-peak …

The Effect Of Skinfold On The Assessment Of The Mean Power Frequency At The Fatigue Threshold, Alyssandra N. Baniqued, Jorge M. Zuniga, Thomas C. Strunc, Katie M. Keenan, Agrini K. Boken, Jeffrey J. Anderson

Journal Articles

The purpose of this study was to determine if the amount of subcutaneous tissue over the quadriceps affects the assessment of mean power frequency at the fatigue threshold (MPFFT). It was hypothesized that greater skinfold values will result in lower power outputs associated to the MPFFT. Fourteen adults (Mean ± SD age = 20.7 ± 0.99; body weight = 72.8 ± 12.6 kg) performed an incremental cycle ergometry test to exhaustion while surface electromyographic (EMG) signals were measured from the vastus lateralis. The skinfold thickness of each leg was taken prior to the test, and skinfold thicknesses were separated into …

Effects Of Aging On The Relationship Between Cognitive Demand And Step Variability During Dual-Task Walking, Leslie M. Decker, Fabien Cignetti, Nathaniel Hunt, Jane F. Potter, Nicholas Stergiou, Stephanie A. Studenski

Journal Articles

A U-shaped relationship between cognitive demand and gait control may exist in dual-task situations, reflecting opposing effects of external focus of attention and attentional resource competition. The purpose of the study was twofold: to examine whether gait control, as evaluated from step-to-step variability, is related to cognitive task difficulty in a U-shaped manner and to determine whether age modifies this relationship. Young and older adults walked on a treadmill without attentional requirement and while performing a dichotic listening task under three attention conditions: non-forced (NF), forced-right (FR), and forced-left (FL). The conditions increased in their attentional demand and requirement for …

Adding Stiffness To The Foot Modulates Soleus Force-Velocity Behaviour During Human Walking, Kota Z. Takahashi, Michael T. Gross, Herman Van Werkhoven, Stephen J. Piazza, Gregory S. Sawicki

Journal Articles

Previous studies of human locomotion indicate that foot and ankle structures can interact in complex ways. The structure of the foot defines the input and output lever arms that influences the force-generating capacity of the ankle plantar flexors during push-off. At the same time, deformation of the foot may dissipate some of the mechanical energy generated by the plantar flexors during push-off. We investigated this foot-ankle interplay during walking by adding stiffness to the foot through shoes and insoles, and characterized the resulting changes in in vivo soleus muscle-tendon mechanics using ultrasonography. Added stiffness decreased energy dissipation at the foot …

The Role Of Environmental Constraints In Walking: Effects Of Steering And Sharp Turns On Gait Dynamics, Dobromir Dotov, Benoit G. Bardy, Simone Dalla Bella

Journal Articles

Stride durations in gait exhibit long-range correlation (LRC) which tends to disappear with certain movement disorders. The loss of LRC has been hypothesized to result from a reduction of functional degrees of freedom of the neuromuscular apparatus. A consequence of this theory is that environmental constraints such as the ones induced during constant steering may also reduce LRC. Furthermore, obstacles may perturb control of the gait cycle and also reduce LRC. To test these predictions, seven healthy participants walked freely overground in three conditions: unconstrained, constrained (constant steering), and perturbed (frequent 90° turns). Both steering and sharp turning reduced LRC …

Division Of Labour: A Democratic Approach Towards Understanding Manual Asymmetries In Non-Human Primates, Madhur Mangalam, Nisarg Desai, Mewa Singh

Journal Articles

A consequence of the 'gold rush'-like hunch for human-like handedness in non-human primates has been that researchers have been continually analysing observations at the level of the population, ignoring the analysis at the level of an individual and, consequently, have potentially missed revelations on the forms and functions of manual asymmetries. Recently, consecutive studies on manual asymmetries in bonnet macaques, Macaca radiata revealed both the functional and adaptive significance of manual asymmetries respectively, and pointed towards the division of labour as being the general principle underlying the observed hand-usage patterns. We review the studies on manual asymmetries in capuchin monkeys, …

Aging Affects Postural Tracking Of Complex Visual Motion Cues, Haralampos Sotirakis, Anastasia Kyvelidou, L. Mademli, Nicholas Stergiou, Vassilia Hatzitaki

Journal Articles

Postural tracking of visual motion cues improves perception–action coupling in aging, yet the nature of the visual cues to be tracked is critical for the efficacy of such a paradigm. We investigated how well healthy older (72.45 ± 4.72 years) and young (22.98 ± 2.9 years) adults can follow with their gaze and posture horizontally moving visual target cues of different degree of complexity. Participants tracked continuously for 120 s the motion of a visual target (dot) that oscillated in three different patterns: a simple periodic (simulated by a sine), a more complex (simulated by the Lorenz attractor that is …

A Perceptual Motor Intervention Improves Play Behavior In Children With Moderate To Severe Cerebral Palsy, Bridget O. Ryalls, Regina T. Harbourne, Lisa Kelly-Vance, Jordan Wickstrom, Nikolaos Stergiou, Anastasia Kyvelidou

Journal Articles

For children with moderate or severe cerebral palsy (CP), a foundational early goal is independent sitting. Sitting offers additional opportunities for object exploration, play and social engagement. The achievement of sitting coincides with important milestones in other developmental areas, such as social engagement with others, understanding of spatial relationships, and the use of both hands to explore objects. These milestones are essential skills necessary for play behavior. However, little is known about how sitting and play behavior might be affected by a physical therapy intervention in children with moderate or severe CP. Therefore, our overall purpose in this study was …

Fission–Fusion Species Under Restricted Living Conditions: A Comparative Study Of Dyadic Interactions And Physical Proximity In Captive Bonobos And Bornean Orangutans, Dorothee Classen, Stefanie Kiessling, Madhur Mangalam, Werner Kaumanns, Mewa Singh

Journal Articles

The present study investigates how the 'fission–fusion-adapted' bonobos and Bornean orangutans manage social relationships when kept under permanent group-living conditions. Our results showed that the bonobos and orangutans did not differ in the overall frequency of dyadic interactions. The orangutans evidently realized a potential to interact with partners, which on a surface did not differ from what was found in the bonobos. However, the bonobos spent more time on sociopositive interactions, especially on grooming and sit in contact, whereas the orangutans agonistically interacted with each other more often. Though frequencies of approaching were similar between the two species, orangutans actively …

Associations Between Mobility, Cognition And Callosal Integrity In People With Parkinsonism, Brett W. Fling, Marian L. Dale, Carolin Curtze, Katrijn Smulders, John G. Nutt, Fay B. Horak

Journal Articles

Falls in people with parkinsonism are likely related to both motor and cognitive impairments. In addition to idiopathic Parkinson's disease (PD), some older adults have lower body parkinsonism (a frontal gait disorder), characterized by impaired lower extremity balance and gait as well as cognition, but without tremor or rigidity. Neuroimaging during virtual gait suggests that interhemispheric, prefrontal cortex communication may be involved in locomotion, but contributions of neuroanatomy connecting these regions to objective measures of gait in people with parkinsonism remains unknown. Our objectives were to compare the integrity of fiber tracts connecting prefrontal and sensorimotor cortical regions …

Perception-Action Mutuality Does Not Obviate Emergence Or The Animal’S Active Role In The Perceptual Act, Dobromir Dotov

Journal Articles

Open peer commentary on the article “Perception-Action Mutuality Obviates Mental Construction” by Martin Flament Fultot, Lin Nie & Claudia Carello. Upshot: The main goal of this commentary is to make more discriminative the comparison between enactive and ecological theories of perception. Emergence at the level of the animal-environment system might be playing the role attributed to mental construction in basic perceptual processes. If correct, this would render some forms of enactivism compatible with the theoretical tenets of the target article.

Mastoid Vibration Affects Dynamic Postural Control During Gait, Jung Chien, Mukul Mukherjee, Nicholas Stergiou

Journal Articles

Our objective was to investigate how manipulating sensory input through mastoid vibration (MV) could affect dynamic postural control during walking, with and without simultaneous manipulation of the visual and the somatosensory systems. We used three levels of MV (none, unilateral, and bilateral) via vibrating elements placed on the mastoid processes. We combined this with the six conditions of the Locomotor Sensory Organization Test (LSOT) paradigm to challenge the visual and somatosensory systems. We hypothesized that MV would affect both amount and temporal structure measures of sway variability during walking and that, in combination with manipulations of the visual and the …

Chapter 8: Autocorrelation Function, Mutual Information, And Correlation Dimension, Nathaniel Hunt

Journal Articles

In this chapter, we will discuss in greater detail the autocorrelation function and the mutual information we mentioned in Chapter 3 on the reconstruction of the state space. We will also cover a new measure called the correlation dimension, which quantifies the dimensionality of an attractor.

Chapter 5: Surrogation, Sara A. Myers

Journal Articles

One of the goals of time series analysis is to understand the underlying mechanisms that generate different dynamics for different time series. If a time series is not a product of random process, then we can assume that some kind of dynamics govern the time series. The question is what kinds of dynamics are controlling the time series. For nonlinear time series analysis, our focus is on nonlinear dynamics, and one of the goals is to characterize those dynamics by applying nonlinear tools. However, it is important to establish evidence of nonlinearity in a time series first in order to …

Chapter 2: Time Series, Sara A. Myers

Journal Articles

Time series is “simply a list of numbers assumed to measure some process sequentially in time” (Stergiou et al. 2004). Mathematicians have a more formal definition, that is, a set or a sequence of observations, with each one recorded at specific times, or at least sequentially (Brockwell and Davis 2002; Box et al. 2008). Time series are created from multiple sources for research purposes to understand various behaviors. For example, social scientists could collect graduation rates, physiologists record heart rates, economists study consumer spending, and climatologists examine weather patterns. Basically, any time observations are taken repeatedly over time, from any …