Biomechanics Commons^™

Mutual Synchronization And Control Between Artificial Chaotic System And Human, Dobromir Dotov, Tom Froese

Journal Articles

Dexterous assistive devices constitute one of the frontiers for hybrid human-machine systems. Manipulating unstable systems requires task-specific anticipatory dynamics. Learning this dynamics is more difficult when tasks, such as carrying liquid or riding a horse, produce unpredictable, irregular patterns of feedback and have hidden dimensions not projected as sensory feedback. We addressed the issue of coordination with complex systems producing irregular behaviour, with the assumption that mutual coordination allows for non-periodic processes to synchronize and in doing so to become regular. Chaos control gives formal expression to this: chaos can be stabilized onto periodic trajectories provided that the structure of …

Individualization Of Music-Based Rhythmic Auditory Cueing In Parkinson's Disease, Simone Dalla Bella, Dobromir Dotov, Benoît Brady, Valérie Cochen De Cock

Journal Articles

Gait dysfunctions in Parkinson's disease can be partly relieved by rhythmic auditory cueing. This consists in asking patients to walk with a rhythmic auditory stimulus such as a metronome or music. The effect on gait is visible immediately in terms of increased speed and stride length. Moreover, training programs based on rhythmic cueing can have long-term benefits. The effect of rhythmic cueing, however, varies from one patient to the other. Patients’ response to the stimulation may depend on rhythmic abilities, often deteriorating with the disease. Relatively spared abilities to track the beat favor a positive response to rhythmic cueing. On …

Individualization Of Music-Based Rhythmic Auditory Cueing In Parkinson's Disease, Simone Dalla Bella, Dobromir Dotov, Benoit G. Bardy, Valérie Cochen De Cock

Journal Articles

Gait dysfunctions in Parkinson's disease can be partly relieved by rhythmic auditory cueing. This consists in asking patients to walk with a rhythmic auditory stimulus such as a metronome or music. The effect on gait is visible immediately in terms of increased speed and stride length. Moreover, training programs based on rhythmic cueing can have long-term benefits. The effect of rhythmic cueing, however, varies from one patient to the other. Patients’ response to the stimulation may depend on rhythmic abilities, often deteriorating with the disease. Relatively spared abilities to track the beat favor a positive response to rhythmic cueing. On …

Gait Stability Has Phase-Dependent Dual-Task Costs In Parkinson’S Disease, Peter C. Fino, Martina Mancini, Carolin Curtze, John G. Nutt, Fay B. Horak

Journal Articles

Dual-task (DT) paradigms have been used in gait research to assess the automaticity of locomotion, particularly in people with Parkinson’s disease (PD). In people with PD, reliance on cortical control during walking leads to greater interference between cognitive and locomotor tasks. Yet, recent studies have suggested that even healthy gait requires cognitive control, and that these cognitive contributions occur at specific phases of the gait cycle. Here, we examined whether changes in gait stability, elicited by simultaneous cognitive DTs, were specific to certain phases of the gait cycle in people with PD. Phase-dependent local dynamic stability (LDS) was calculated for …

Biomechanical Gait Variable Estimation Using Wearable Sensors After Unilateral Total Knee Arthroplasty, Ik-Hyun Youn, Jong-Hoon Youn, Joseph A. Zeni, Brian A. Knarr

Journal Articles

Total knee arthroplasty is a common surgical treatment for end-stage osteoarthritis of the knee. The majority of existing studies that have explored the relationship between recovery and gait biomechanics have been conducted in laboratory settings. However, seamless gait parameter monitoring in real-world conditions may provide a better understanding of recovery post-surgery. The purpose of this study was to estimate kinematic and kinetic gait variables using two ankle-worn wearable sensors in individuals after unilateral total knee arthroplasty. Eighteen subjects at least six months post-unilateral total knee arthroplasty participated in this study. Four biomechanical gait variables were measured using an instrumented split-belt …

Gait Asymmetry In People With Parkinson’S Disease Is Linked To Reduced Integrity Of Callosal Sensorimotor Regions, Brett W. Fling, Carolin Curtze, Fay B. Horak

Journal Articles

Background: Individuals with Parkinson’s disease (PD) often manifest significant temporal and spatial asymmetries of the lower extremities during gait, which significantly contribute to mobility impairments. While the neural mechanisms underlying mobility asymmetries within this population remain poorly understood, recent evidence points to altered microstructural integrity of white matter fiber tracts within the corpus callosum as potentially playing a substantial role.

Objectives: The purpose of this study was to quantify spatial and temporal gait asymmetries as well as transcallosal microstructural integrity of white matter fiber tracts connecting the primary and secondary sensorimotor cortices in people with PD and age-matched control participants. …

Rhythmic Abilities And Musical Training In Parkinson’S Disease: Do They Help?, Valérie Cochen De Cock, Dobromir Dotov, Petra Ihalainen, V. Bégel, Florence Galtier, Cindy Lebrun, Marie Christine Picot, Valérie Driss, N. Landragin, Christian Geny, Benoit G. Bardy, Simone Dalla Bella

Journal Articles

Rhythmic auditory cues can immediately improve gait in Parkinson’s disease. However, this effect varies considerably across patients. The factors associated with this individual variability are not known to date. Patients’ rhythmic abilities and musicality (e.g., perceptual and singing abilities, emotional response to music, and musical training) may foster a positive response to rhythmic cues. To examine this hypothesis, we measured gait at baseline and with rhythmic cues in 39 non-demented patients with Parkinson’s disease and 39 matched healthy controls. Cognition, rhythmic abilities and general musicality were assessed. A response to cueing was qualified as positive when the stimulation led to …

Bi-Articular Knee-Ankle-Foot Exoskeleton Produces Higher Metabolic Cost Reduction Than Weight-Matched Mono-Articular Exoskeleton, Philippe Malcolm, Samuel Galle, Dirk De Clercq

Journal Articles

The bi-articular m. gastrocnemius and the mono-articular m. soleus have different and complementary functions during walking. Several groups are starting to use these biological functions as inspiration to design prostheses with bi-articular actuation components to replace the function of the m. gastrocnemius. Simulation studies indicate that a bi-articular configuration and spring that mimic the m. gastrocnemius could be beneficial for orthoses or exoskeletons. Our aim was to test the effect of a bi-articular and spring configuration that mimics the m. gastrocnemius and compare this to a no- spring and mono-articular configuration. We tested nine participants during walking with knee-ankle-foot exoskeletons …

Infant Sitting Postural Control Appears Robust Across Changes In Surface Context, Elena Kokkoni, Joshua Haworth, Regina T. Harbourne, Nicholas Stergiou, Anastasia Kyvelidou

Journal Articles

Aim of the study: Independent sitting requires the control of the involved body segments over the base of support using information obtained from the three sensory systems (visual, vestibular, and somatosensory). The contribution of somatosensory information in infant sitting has not been explored. To address this gap, we altered the context of the sitting support surface and examined the infants’ immediate postural responses.

Materials and methods: Ten 7-month-old typically developing infants sat on compliant and firm surfaces in one session. Spatial, frequency, and temporal measures of postural control were obtained using center of pressure data.

Results Our results suggest that …

Prosthetic Energy Return During Walking Increases After 3 Weeks Of Adaptation To A New Device, Samuel F. Ray, Shane R. Wurdeman, Kota Z. Takahashi

Journal Articles

Background: There are many studies that have investigated biomechanical differences among prosthetic feet, but not changes due to adaptation over time. There is a need for objective measures to quantify the process of adaptation for individuals with a transtibial amputation. Mechanical power and work profiles are a primary focus for modern energystorage- and-return type prostheses, which strive to increase energy return from the prosthesis. The amount of energy a prosthesis stores and returns (i.e., negative and positive work) during stance is directly influenced by the user’s loading strategy, which may be sensitive to alterations during the course of an adaptation …

Coactivation Index Of Children With Congenital Upper Limb Reduction Deficiencies Before And After Using A Wristdriven 3d Printed Partial Hand Prosthesis, Jorge Zuniga, Dimitrios Kastavelis, Jean Peck, Rakesh Srivastava, James E. Pierce, Drew R. Dudley, David A. Salazar, Keaton J. Young, Brian A. Knarr

Journal Articles

Background: Co-contraction is the simultaneous activation of agonist and antagonist muscles that produces forces around a joint. It is unknown if the use of a wrist-driven 3D printed transitional prostheses has any influence on the neuromuscular motor control strategies of the affected hand of children with unilateral upper-limb reduction deficiencies. Thus, the purpose of the current investigation was to examine the coactivation index (CI) of children with congenital upper-limb reduction deficiencies before and after 6 months of using a wrist-driven 3D printed partial hand prosthesis.

Methods: Electromyographic activity of wrist flexors and extensors (flexor carpi ulnaris and extensor …

Introducing Statistical Persistence Decay – A Quantification Of Stride-To-Stride Time Interval Dependency In Human Gait, P. C. Raffalt, J. M. Yentes

Journal Articles

Stride-to-stride time intervals during human walking are characterised by predictability and statistical persistence quantified by sample entropy (SaEn) and detrended fluctuation analysis (DFA) which indicates a time dependency in the gait pattern. However, neither analyses quantify time dependency in a physical or physiological interpretable time scale. Recently, entropic half-life (ENT½) has been introduced as a measure of the time dependency on an interpretable time scale. A novel measure of time dependency, based on DFA, statistical persistence decay (SPD), was introduced. The present study applied SaEn, DFA, ENT½, and SPD in known theoretical signals (periodic, chaotic, and random) and stride-to-stride time …

Reduced Vertical Displacement Of The Center Of Mass Is Not Accompanied By Reduced Oxygen Uptake During Walking, Shane R. Wurdeman, Peter C. Raffalt, Nicholas Stergiou

Journal Articles

The six determinants of gait proposed that the goal of gait is to minimize vertical displacement of the body’s center of mass (CoM) with the objective to optimize energy expenditure. On the contrary, recent investigations suggest that reduced vertical displacement leads to an increase in energy expenditure. However, these investigations had the included subjects deliberately changing their gait, which could bias the endpoint measures. The present study investigated the effect of reduced vertical displacement of the CoM on oxygen uptake and walking economy without imposing altered gait patterns. This was accomplished by having subjects walk on a curved treadmill and …

Biomechanics (Chapter 9), Nicholas Stergiou, K.-C. Siu, Sara Myers, Ben Senderling

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. Kinesiology, the parent discipline of biomechanics, is a science that investigates movement. Biomechanical research in human development focuses on evaluating essential movement patterns across the human life span. Biomechanical analysis is specifically important in quantifying the developmental motor skills and movement patterns such as walking, kicking, jumping, throwing, and catching. Biomechanical research also involves studying the movement patterns of injured and disabled people. Forensic biomechanists are invited to analyze evidence, clarify some …

Energy Neutral: The Human Foot And Ankle Subsections Combine To Produce Near Zero Net Mechanical Work During Walking, Kota Z. Takahashi, Kate Worster, Dustin A. Bruening

Journal Articles

The human foot and ankle system is equipped with structures that can produce mechanical work through elastic (e.g., Achilles tendon, plantar fascia) or viscoelastic (e.g., heel pad) mechanisms, or by active muscle contractions. Yet, quantifying the work distribution among various subsections of the foot and ankle can be difficult, in large part due to a lack of objective methods for partitioning the forces acting underneath the stance foot. In this study, we deconstructed the mechanical work production during barefoot walking in a segment-by-segment manner (hallux, forefoot, hindfoot, and shank). This was accomplished by isolating the forces acting within each foot …

Functional Changes Through The Usage Of 3d-Printed Transitional Prostheses In Children, Jorge Zuniga, Jean Peck, Rakesh Srivastava, James E. Pierce, Drew Dudley, Nicholas T. Than, Nicholas Stergiou

Journal Articles

Introduction: There is limited knowledge on the use of 3 D-printed transitional prostheses, as they relate to changes in function and strength. Therefore, the purpose of this study was to identify functional and strength changes after usage of 3 D-printed transitional prostheses for multiple weeks for children with upper-limb differences.

Materials and methods: Gross manual dexterity was assessed using the Box and Block Test and wrist strength was measured using a dynamometer. This testing was conducted before and after a period of 24 ± 2.61 weeks of using a 3 D-printed transitional prosthesis. The 11 children (five girls and six …

Reliability Of A Feedback-Controlled Treadmill Algorithm Dependent On The User's Behavior, Casey Wiens, William Denton, Molly Schieber, Ryan Hartley, Vivien Marmelat, Sara A. Myers, Jennifer M. Yentes

Journal Articles

he reliability of the treadmill belt speed using a feedback-controlled treadmill algorithm was analyzed in this study. Using biomechanical factors of the participant's walking behavior, an estimated walking speed was calculated and used to adjust the speed of the treadmill. Our proposed algorithm expands on the current hypotheses of feedback-controlled treadmill algorithms and is presented below. Nine healthy, young adults walked on a treadmill controlled by the algorithm for three trials over two days. Each participant walked on the feedback-controlled treadmill for one 16-minute and one five-minute trial during day one and one 16-minute trial during day two. Mean, standard …

Multifractality, Interactivity, And The Adaptive Capacity Of The Human Movement System: A Perspective For Advancing The Conceptual Basis Of Neurologic Physical Therapy, Jon Cavanaugh, Damian G. Kelty-Stephen, Nicholas Stergiou

Journal Articles

Background and Purpose:

Physical therapists seek to optimize movement as a means of reducing disability and improving health. The short-term effects of interventions designed to optimize movement ultimately are intended to be adapted for use across various future patterns of behavior, in potentially unpredictable ways, with varying frequency, and in the context of multiple tasks and environmental conditions. In this perspective article, we review and discuss the implications of recent evidence that optimal movement variability, which previously had been associated with adaptable motor behavior, contains a specific complex nonlinear feature known as “multifractality.”

Summary of Key Points:

Multifractal movement fluctuation …

Human-In-The-Loop Bayesian Optimization Of Wearable Device Parameters, Myunghee Kim, Ye Ding, Philippe Malcolm, Jozefien Speeckaert, Christopher Siviy, Conor J. Walsh

Journal Articles

The increasing capabilities of exoskeletons and powered prosthetics for walking assistance have paved the way for more sophisticated and individualized control strategies. In response to this opportunity, recent work on human-in-the-loop optimization has considered the problem of automatically tuning control parameters based on realtime physiological measurements. However, the common use of metabolic cost as a performance metric creates significant experimental challenges due to its long measurement times and low signal-to-noise ratio. We evaluate the use of Bayesian optimization—a family of sample-efficient, noise-tolerant, and global optimization methods—for quickly identifying near-optimal control parameters. To manage experimental complexity and provide comparisons against related …

Dynamics Of Stride Interval Characteristics During Continuous Stairmill Climbing, Peter C. Raffalt, Srikant Vallabhajosula, Jessica J. Renz, Mukul Mukherjee, Nikolaos Stergiou

Journal Articles

It has been shown that statistical persistence in stride intervals characteristics exist during walking, running and cycling and were speed-dependent among healthy young adults. The purpose of this study was to determine if such statistical persistence in stride time interval, stride length and stride speed also exists during self-paced continuous stairmill climbing and if the strength is dependent on stepping rate. Stride time, stride length, and stride speed were collected from nine healthy participants during 3 min of stairmill climbing at 100, 110, and 120% of their preferred stepping rate (PSR) and 5 min of treadmill walking at preferred walking …

Effects Of Adaptive-Tempo Music-Based Ras For Parkinson’S Disease Patients, Bart Moens, Leon Van Noorden, Wim De Wilde, Micheline Lesaffre, Dirk Cambier, Dobromir Dotov, Patrick Santens, Jana Blomme, Heleen Soens, Marc Leman

Journal Articles

The use of Rhythmic Auditory Stimulation (RAS) is a potential method to help Parkinson Patients improve their gait characteristics. By providing auditory stimuli such as a metronome or music, gait impairments, which characterize the illness, tend to improve without pharmacological or surgical intervention. This work evaluates three different RAS approaches: fixed-tempo metronomes, fixed-tempo music and adaptive-tempo music. 29 Parkinson Disease (PD) patients were tested in a repeated measures experiment to compare spatiotemporal gait parameters in different cueing conditions. Baseline measures without RAS were taken, followed by counterbalanced trials of the three RAS methods. Compared to the baseline, beneficial effects were …

Dynamic Balance Changes Within Three Weeks Of Fitting A New Prosthetic Foot Component, Jenny A. Kent, Nicholas Stergiou, Shane R. Wurdeman

Journal Articles

Balance during walking is of high importance to prosthesis users and may affect walking during baseline observation and evaluation. The aim of this study was to determine whether changes in walking balance occurred during an adaptation period following the fitting of a new prosthetic component.

Margin of stability in the medial-lateral direction (MOSML) and an anterior instability margin (AIM) were used to quantify the dynamic balance of 21 unilateral transtibial amputees during overground walking. Participants trialled two prosthetic feet presenting contrasting movement/balance constraints; a Higher Activity foot similar to that of their own prosthesis, and a Lower Activity foot. Participants …

Muscle Strength And Control Characteristics Are Altered By Peripheral Artery Disease, Molly Schieber, Ryan Hasenkamp, Iraklis Pipinos, Jason Johanning, Nicholas Stergiou, Holly Despiegelaere, Jung Chien, Sara A. Myers

Journal Articles

Objective

Methods

Varying Negative Work Assistance At The Ankle With A Soft Exosuit During Loaded Walking, Philippe Malcolm, Sangjun Lee, Simon Crea, Christopher Siviy, Fabricio Saucedo, Ignacio Galiana, Fausto A. Panizzolo, Kenneth G. Holt, Conor J. Walsh

Journal Articles

Background: Only very recently, studies have shown that it is possible to reduce the metabolic rate of unloaded and loaded walking using robotic ankle exoskeletons. Some studies obtained this result by means of high positive work assistance while others combined negative and positive work assistance. There is no consensus about the isolated contribution of negative work assistance. Therefore, the aim of the present study is to examine the effect of varying negative work assistance at the ankle joint while maintaining a fixed level of positive work assistance with a multi-articular soft exosuit.

Methods: We tested eight participants during …

Gait Deficiencies Associated With Peripheral Artery Disease Are Different Than Chronic Obstructive Pulmonary Disease, John D. Mccamley, Eric J. Pisciotta, Jennifer M. Yentes, Shane R. Wurdeman, Stephen I. Rennard, Iraklis I. Pipinos, Jason M. Johanning, Sara A. Myers

Journal Articles

Objective: Previous studies have indicated that patients with peripheral artery disease (PAD), display significant differences in their kinetic and kinematic gait characteristics when compared to healthy, aged-matched controls. The ability of patients with chronic obstructive pulmonary disease (COPD) to ambulate is also limited. These limitations are likely due to pathology-driven muscle morphology and physiology alterations establish in PAD and COP, respectively. Gait changes in PAD were compared to gait changes due to COPD to further understand how altered limb muscle due to disease can alter walking patterns. Both groups were independently compared to healthy controls. It was hypothesized that both …

Muscle Strength And Control Characteristics Are Altered By Peripheral Artery Disease, Molly Schieber, Ryan Hasenkamp, Iraklis Pipinos, Jason Johanning, Nicholas Stergiou, Holly Despiegelaere, Jung Chien, Sara Myers

Journal Articles

Objective

Peripheral artery disease (PAD), a common manifestation of atherosclerosis, is characterized by lower leg ischemia and myopathy in association with leg dysfunction. Patients with PAD have impaired gait from the first step they take with consistent defects in the movement around the ankle joint, especially in plantar flexion. Our goal was to develop muscle strength profiles to better understand the problems in motor control responsible for the walking impairment in patients with PAD.

Methods

Ninety-four claudicating PAD patients performed maximal isometric plantar flexion contractions lasting 10 seconds in two conditions: pain free (patient is well rested and has …

Posture And Gaze Tracking Of A Vertically Moving Target Reveals Age-Related Constraints In Visuo-Motor Coupling, Haralampos Sotirakis, Anastasia Kyvelidou, Nicholas Stergiou, Vassilia Hatzitaki

Journal Articles

Previously we have demonstrated that the effect of aging on posture and gaze active tracking of a visual target moving in the horizontal direction is dependent on target’s complexity. In this study, we asked whether a similar phenomenon is present when tracking a visual target moving with varying complexity in the vertical direction. Ten young (22.98 ± 2.9 years) and 10 older adults (72.45 ± 4.72 years) tracked for 120 s, a visual target moving vertically by shifting their bodyweight in the anterior-posterior direction. Three target motions were tested: a simple periodic (sine wave), a more complex (Lorenz attractor) and …

Patients With Chronic Obstructive Pulmonary Disease Walk With Altered Step Time And Step Width Variability As Compared With Healthy Control Subjects, Jennifer M. Yentes, Stephen I. Rennard, Kendra K. Schmid, Daniel Blanke, Nikolaos Stergiou

Journal Articles

Rationale: Compared with control subjects, patients with chronic obstructive pulmonary disease (COPD) have an increased incidence of falls and demonstrate balance deficits and alterations in mediolateral trunk acceleration while walking. Measures of gait variability have been implicated as indicators of fall risk, fear of falling, and future falls.

Objectives: To investigate whether alterations in gait variability are found in patients with COPD as compared with healthy control subjects.

Methods: Twenty patients with COPD (16 males; mean age, 63.6 ± 9.7 yr; FEV1/FVC, 0.52 ± 0.12) and 20 control subjects (9 males; mean age, 62.5 ± 8.2 yr) walked for 3 …

Patients With Chronic Obstructive Pulmonary Disease Walk With Altered Step Time And Step Width Variability As Compared With Healthy Control Subjects, Jennifer M. Yentes, Stephen I. Rennard, Kendra K. Schmid, Daniel Blanke, Nicholas Stergiou

Journal Articles

Rationale: Compared with control subjects, patients with chronic obstructive pulmonary disease (COPD) have an increased incidence of falls and demonstrate balance deficits and alterations in mediolateral trunk acceleration while walking. Measures of gait variability have been implicated as indicators of fall risk, fear of falling, and future falls.

Objectives: To investigate whether alterations in gait variability are found in patients with COPD as compared with healthy control subjects.

Methods: Twenty patients with COPD (16 males; mean age, 63.6 ± 9.7 yr; FEV1/FVC, 0.52 ± 0.12) and 20 control subjects (9 males; mean age, 62.5 ± 8.2 yr) walked for 3 …

Reliability Of Center Of Pressure Measures For Assessing The Development Of Sitting Postural Control Through The Stages Of Sitting, Jordan Wickstrom, Nicholas Stergiou, Anastasia Kyvelidou

Journal Articles

Cerebral palsy (CP) impairs an individual’s ability to move and control one’s posture. Unfortunately, the signs and symptoms of CP may not be apparent before age two. Evaluating sitting posture is a potential way to assess the developing mechanisms that contribute to CP. The purpose of this project was to determine the reliability of linear and nonlinear measures, including inter- and intrastage reliability, when used to analyze the center of pressure (COP) time series during the stages of sitting development in children with typical development (TD) and with/at-risk for cerebral palsy (CP). We hypothesized that nonlinear tools would be more …