Biomechanics Commons^™

A Low-Cost, Wireless Near-Infrared Spectroscopy Device Detects The Presence Of Lower Extremity Atherosclerosis As Measured By Computed Tomographic Angiography And Characterizes Walking Impairment In Peripheral Artery Disease, Matthew A. Fuglestad, Hernan Hernandez, Yue Gao, Henamari Ybay, Molly Schieber, Katyarina E. Brunette, Sara A. Myers, George P. Casale, Iraklis Pipinos

Journal Articles

Background

Methods

Supervised Walking Exercise Therapy Improves Gait Biomechanics In Patients With Peripheral Artery Diseas, Molly Schieber, Iraklis Pipinos, Jason M. Johanning, George P. Casale, Mark A. Williams, Holly Despiegelaere, Ben Senderling, Sara A. Myers

Journal Articles

Objective

Methods

Locomotor Patterns Change Over Time During Walking On An Uneven Surface, Jenny A. Kent, Joel H. Sommerfeld, Mukul Mukherjee, Kota Z. Takahashi, Nicholas Stergiou

Journal Articles

During walking, uneven surfaces impose new demands for controlling balance and forward progression at each step. It is unknown to what extent walking may be refined given an amount of stride-to-stride unpredictability at the distal level. Here, we explored the effects of an uneven terrain surface on whole-body locomotor dynamics immediately following exposure and after a familiarization period. Eleven young, unimpaired adults walked for 12 min on flat and uneven terrain treadmills. The whole-body center of mass excursion range (COM_exc) and peak velocity (COM_vel), step length and width were estimated. On first exposure to uneven terrain, …

The Foot And Ankle Structures Reveal Emergent Properties Analogous To Passive Springs During Human Walking, Erica Hedrick, Steven J. Stanhope, Kota Z. Takahashi

Journal Articles

An objective understanding of human foot and ankle function can drive innovations of bio-inspired wearable devices. Specifically, knowledge regarding how mechanical force and work are produced within the human foot-ankle structures can help determine what type of materials or components are required to engineer devices. In this study, we characterized the combined functions of the foot and ankle structures during walking by synthesizing the total force, displacement, and work profiles from structures distal to the shank. Eleven healthy adults walked at four scaled speeds. We quantified the ground reaction force and center-of-pressure displacement in the shank’s coordinate system during stance …

Alterations In Cortical Activation Among Individuals With Chronic Ankle Instability During Single-Limb Postural Control, Adam Rosen, Jennifer M. Yentes, Melanie L. Mcgrath, Arthur C. Maerlender, Sara A. Myers, Mukul Mukherjee

Journal Articles

Context

Chronic ankle instability (CAI) is characterized by repetitive ankle sprains and perceived instability. Whereas the underlying cause of CAI is disputed, alterations in cortical motor functioning may contribute to the perceived dysfunction.

Objective

To assess differences in cortical activity during single-limb stance among control, coper, and CAI groups.

Design

Cross-sectional study.

Setting

Biomechanics laboratory.

Patients or Other Participants

A total of 31 individuals (10 men, 21 women; age = 22.3 ± 2.4 years, height = 169.6 ± 9.7 cm, mass = 70.6 ± 11.6 kg), who were classified into control (n = 13), coper (n = 7), and CAI …

Synchronization Dynamics Modulates Stride-To-Stride Fluctuations When Walking To An Invariant But Not To A Fractal-Like Stimulus, Joao R. Vaz, Boman Groff, Douglas Rowen, Brian Knarr, Nicholas Stergiou

Journal Articles

Walking with different types of cueing/stimulus (i.e. auditory, visual) has been shown to alter gait variability, thus emerging as an innovative therapeutical tool to restore abnormal gait variability in clinical populations. However, the majority of the research in this area has focused on auditory stimuli while visual stimuli are an understudied alternative that needs more attention, particularly due to the natural dependence on vision during walking. Furthermore, the time differences between the occurrences of the walking steps and the sensory cues, also known as asynchronies, have also received minimal attention, even though the ability to synchronize with different stimuli is …

The Role Of Interaction And Predictability In The Spontaneous Entrainment Of Movement., Dobromir Dotov, Valérie Cochen De Cock, Christian Geny, Petra Ihalainen, Bart Moens, Marc Leman, Benoît Brady, Simone Dalla Bella

Journal Articles

People walking side by side spontaneously synchronize their steps on some occasions but not on others, which poses a challenge to theories of perception-action based on interactive dynamic systems. How can action be spontaneously entrained by some sources of perceptual information while others are selectively ignored? The predictive processing framework suggests that saliency factors such as stimulus predictability, consistent deviation, and interactivity of the stimulus control the coupling between the motor system and perceptual information. To test this, we compared entrainment of gait cadence by two interactive auditory stimuli and two noninteractive but predictable, faster than preferred stimuli that were …

An Altered Spatiotemporal Gait Adjustment During A Virtual Obstacle Crossing Task In Patients With Diabetic Peripheral Neuropathy, Chun-Kai Huang, Vijay Shivaswamy, Pariwat Thaisetthawatkul, Lynn Mack, Nicholas Stergiou, Ka-Chun Siu

Journal Articles

This study investigates spatiotemporal gait adjustments that occur while stepping over virtual obstacles during treadmill walking in people with/without diabetic peripheral neuropathy (DPN). Eleven adults with Type 2 diabetes mellitus, ten DPN, and 11 age-matched healthy adults (HTY) participated in this study. They stepped over forthcoming virtual obstacles during treadmill walking. Outcomes such as success rate, spatiotemporal gait characteristics during obstacle crossing, and correlations between these variables were evaluated. The results partially supported our hypotheses that when comparing with HTY and DM, people with DPN adopted a crossing strategy which decreased obstacle crossing success rate and maximal toe elevation, …

Uneven Terrain Exacerbates The Deficits Of A Passive Prosthesis In The Regulation Of Whole Body Angular Momentum In Individuals With A Unilateral Transtibial Amputation, Jenny A. Kent, Kota Z. Takahashi, Nicholas Stergiou

Journal Articles

Background

Uneven ground is a frequently encountered, yet little-studied challenge for individuals with amputation. The absence of control at the prosthetic ankle to facilitate correction for surface inconsistencies, and diminished sensory input from the extremity, add unpredictability to an already complex control problem, and leave limited means to produce appropriate corrective responses in a timely manner. Whole body angular momentum, L, and its variability across several strides may provide insight into the extent to which an individual can regulate their movement in such a context. The aim of this study was to explore L in individuals with a transtibial amputation, …

Gait Mechanics Differences Between Healthy Controls And Patients With Peripheral Artery Disease After Adjusting For Gait Velocity, Stride Length, And Step Width, John D. Mccamley, Eric Cutler, Kendra K. Schmid, Shane R. Wurdeman, Jason Johanning, Iraklis Pipinos, Sara A. Myers

Journal Articles

Patients with peripheral artery disease (PAD) experience significant leg dysfunction. The effects of PAD on gait include shortened steps, slower walking velocity, and altered gait kinematics and kinetics, which may confound joint torques and power measurements. Spatiotemporal parameters and joint torques and powers were calculated and compared between 20 patients with PAD and 20 healthy controls using independent t tests. Separate analysis of covariance models were used to evaluate group differences after independently adjusting for gait velocity, stride length, and step width. Compared with healthy controls, patients with PAD exhibited reduced peak extensor and flexor torques at the knee and …

Selection Procedures For The Largest Lyapunov Exponent In Gait Biomechanics, Peter C. Raffalt, Jenny A. Kent, Shane R. Wurdeman, Nicholas Stergiou

Journal Articles

The present study was aimed at investigating the effectiveness of the Wolf et al. (LyE_W) and Rosenstein et al. largest Lyapunov Exponent (LyE_R) algorithms to differentiate data sets with distinctly different temporal structures. The three-dimensional displacement of the sacrum was recorded from healthy subjects during walking and running at two speeds; one low speed close to the preferred walking speed and one high speed close to the preferred running speed. LyE_R and LyE_W were calculated using four different time series normalization procedures. The performance of the algorithms were evaluated based on their ability to return relative low values for slow …

Stride-Time Variability Is Related To Sensorimotor Cortical Activation During Forward And Backward Walking, Boman Groff, Prokopios Antonellis, Kendra K. Schmid, Brian Knarr, Nicholas Stergiou

Journal Articles

Previous research has used functional near-infrared spectroscopy (fNIRS) to show that motor areas of the cortex are activated more while walking backward compared to walking forward. It is also known that head movement creates motion artifacts in fNIRS data. The aim of this study was to investigate cortical activation during forward and backward walking, while also measuring head movement. We hypothesized that greater activation in motor areas while walking backward would be concurrent with increased head movement. Participants performed forward and backward walking on a treadmill. Participants wore motion capture markers on their head to quantify head movement and pressure …

Multi-Scale Coordination Of Distinctive Movement Patterns During Embodied Interaction Between Adults With High-Functioning Autism And Neurotypicals, Leonardo Zapata-Fonseca, Dobromir Dotov, Ruben Fossion, Tom Froese, Leonhard Schilbach, Kai Vogeley, Bert Timmermans

Journal Articles

Autism Spectrum Disorder (ASD) can be understood as a social interaction disorder. This requires researchers to take a “second-person” stance and to use experimental setups based on bidirectional interactions. The present work offers a quantitative description of movement patterns exhibited during computer-mediated real-time sensorimotor interaction in 10 dyads of adult participants, each consisting of one control individual (CTRL) and one individual with high-functioning autism (HFA). We applied time-series analyses to their movements and found two main results. First, multi-scale coordination between participants was present. Second, despite this dyadic alignment and our previous finding that individuals with HFA can be equally …

Walking Speed And Spatiotemporal Step Mean Measures Are Reliable During Feedback-Controlled Treadmill Walking; However, Spatiotemporal Step Variability Is Not Reliable, Casey Wiens, William Denton, Molly Schieber, Vivien Marmelat, Sara A. Myers, Jennifer M. Yentes

Journal Articles

The purpose of the study was to compare the effects of a feedback-controlled treadmill (FeedbackTM) to a traditional fixed-speed treadmill (FixedTM) on spatiotemporal gait means, variability, and dynamics. The study also examined inter-session reliability when using the FeedbackTM. Ten young adults walked on the FeedbackTM for a 5-minute familiarization followed by a 16-minute experimental trial. They returned within one week and completed a 5-minute familiarization followed by a 16-minute experimental trial each for FeedbackTM and FixedTM conditions. Mean walking speed and step time, length, width, and speed means and coefficient of variation were calculated from all experimental conditions. Step time, …

The Effects Of Ankle Stiffness On Mechanics And Energetics Of Walking With Added Loads: A Prosthetic Emulator Study, Erica Hedrick, Philippe Malcolm, Jason M. Wilken, Kota Z. Takahashi

Journal Articles

Background: The human ankle joint has an influential role in the regulation of the mechanics and energetics of gait. The human ankle can modulate its joint ‘quasi-stiffness’ (ratio of plantarflexion moment to dorsiflexion displacement) in response to various locomotor tasks (e.g., load carriage). However, the direct effect of ankle stiffness on metabolic energy cost during various tasks is not fully understood. The purpose of this study was to determine how net metabolic energy cost was affected by ankle stiffness while walking under different force demands (i.e., with and without additional load).
Methods: Individuals simulated an amputation by using …

Visual And Somatosensory Contributions To Infant Sitting Postural Control, Anastasia Kyvelidou, Nicholas Stergiou

Journal Articles

There are a limited number of studies that have investigated sitting posture during infancy and the contribution of the sensory systems. The goal of this study was to examine the effects of altered visual and somatosensory signals on infant sitting postural control. Thirteen infants (mean age ± SD, 259.69 ± 16.88 days) participated in the study. Initially, a single physical therapist performed the Peabody Developmental Motor Scale to determine typical motor development. Then the child was placed onto a force platform under four randomized conditions: (a) Control (C) – sat independently on the force plate, (b) Somatosensory (SS) – Sat …

Lower Limb Joint Angle Variability And Dimensionality Are Different In Stairmill Climbing And Treadmill Walking, Peter C. Raffalt, Srikant Vallabhajosula, Jessica Renz, Mukul Mukherjee, Nicholas Stergiou

Journal Articles

The present study tested if the quadratic relationship which exists between stepping frequency and gait dynamics in walking can be generalized to stairmill climbing. To accomplish this, we investigated the joint angle dynamics and variability during continuous stairmill climbing at stepping frequencies both above and below the preferred stepping frequency (PSF). Nine subjects performed stairmill climbing at 80, 90, 100, 110 and 120% PSF and treadmill walking at preferred walking speed during which sagittal hip, knee and ankle angles were extracted. Joint angle dynamics were quantified by the largest Lyapunov exponent (LyE) and correlation dimension (CoD). Joint angle variability was …

Optimizing Beat Synchronized Running To Music, Jeska Buhmann, Edith Van Dyck, Dobromir Dotov, Marc Leman, Bart Moens

Journal Articles

The use of music and specifically tempo-matched music has been shown to affect running performance. But can we maximize the synchronization of movements to music and does maximum synchronization influence kinematics and motivation? In this study, we explore the effect of different types of music-to-movement alignment strategies on phase coherence, cadence and motivation. These strategies were compared to a control condition where the music tempo was deliberately not aligned to the running cadence. Results show that without relative phase alignment, a negative mean asynchrony (NMA) of footfall timings with respect to the beats is obtained. This means that footfalls occurred …

When Coordinating Finger Tapping To A Variable Beat The Variability Scaling Structure Of The Movement And The Cortical Bold Signal Are Both Entrained To The Auditory Stimuli, Steven Harrison, Michael Hough, Kendra K. Schmid, Boman Groff, Nicholas Stergiou

Journal Articles

Rhythmic actions are characterizable as a repeating invariant pattern of movement together with variability taking the form of cycle-to-cycle fluctuations. Variability in behavioral measures is atypically random, and often exhibits serial temporal dependencies and statistical self-similarity in the scaling of variability magnitudes across timescales. Self-similar (i.e. fractal) variability scaling is evident in measures of both brain and behavior. Variability scaling structure can be quantified via the scaling exponent (α) from detrended fluctuation analysis (DFA). Here we study the task of coordinating thumb-finger tapping to the beats of constructed auditory stimuli. We test the hypothesis that variability scaling evident …

Sampling Frequency Influences Sample Entropy Of Kinematics During Walking, Peter C. Raffalt, John D. Mccamley, William Denton, Jennifer M. Yentes

Journal Articles

Sample entropy (SaEn) has been used to assess the regularity of lower limb joint angles during walking. However, changing sampling frequency and the number of included strides can potentially affect the sample entropy. The present study investigated the effect of sample frequency and the number of included strides on the calculations of SaEn in joint angle signals recorded during treadmill walking. Eleven subjects walked at their preferred walking speed for 10 minutes, and SaEn was calculated on sagittal plane hip, knee and ankle angle signals extracted from 50, 100, 200, 300 and 400 strides at sampling frequencies of 60, 120, …

Optic Flow Improves Step Width And Length In Older Adults While Performing Dual Task, Taylor Leeder, Farah Fallahtafti, Molly Schieber, Sara A. Myers, Julie Blaskewicz Boron, Jennifer M. Yentes

Journal Articles

Background

Dual-task paradigms are used to investigate gait and cognitive declines in older adults (OA). Optic-flow is a virtual reality environment where the scene flows past the subject while walking on a treadmill, mimicking real-life locomotion.

Aims

To investigate cost of environment (no optic-flow v. optic-flow) while completing single- and dual-task walking and dual-task costs (DTC; single- v. dual-task) in optic-flow and no optic-flow environments.

Methods

Twenty OA and seven younger adults (YA) walked on a self-paced treadmill in 3-min segments per task and both environments. Five task conditions included: no task, semantic fluency (category), phonemic fluency (letters), word reading, …

Altering Gait Variability With An Ankle Exoskeleton, Prokopios Antonellis, Samuel Galle, Dirk De Clercq, Philippe Malcolm

Journal Articles

Exoskeletons can influence human gait. A healthy gait is characterized by a certain amount of variability compared to a non-healthy gait that has more inherent variability; however which exoskeleton assistance parameters are necessary to avoid increasing gait variability or to potentially lower gait variability below that of unassisted walking are unknown. This study investigated the interaction effects of exoskeleton timing and power on gait variability. Ten healthy participants walked on a treadmill with bilateral ankle-foot exoskeletons under ten conditions with different timing (varied from 36% to 54% of the stride) and power (varied from 0.2 to 0.5 W∙kg-1) combinations. We …

Orderliness Of Visual Stimulus Motion Mediates Sensorimotor Coordination, Joshua L. Haworth, Nicholas Stergiou

Journal Articles

We explored the coupling of gaze and postural sway to the motion of a visual stimulus, to further understand sensorimotor coordination. Visual stimuli consisted of a horizontally oscillating red dot, moving with periodic (sine), chaotic, or aperiodic (brown noise) temporal structure. Cross Recurrence Quantification Analysis (cRQA) was used to investigate the coupling between each measured signal with the time series of the visual stimulus position. The cRQA parameter of percent determinism indicated similar strength of coupling of gaze with either periodic or chaotic motion structures, yet weaker coupling to aperiodic stimulus motion. The cRQA parameter of Maxline indicated a particular …

On The Choice Of Multiscale Entropy Algorithm For Quantification Of Complexity In Gait Data, Peter C. Raffalt, William Denton, Jennifer M. Yentes

Journal Articles

The present study aimed at identifying a suitable multiscale entropy (MSE) algorithm for assessment of complexity in a stride-to-stride time interval time series. Five different algorithms were included (the original MSE, refine composite multiscale entropy (RCMSE), multiscale fuzzy entropy, generalized multiscale entropy and intrinsic mode entropy) and applied to twenty iterations of white noise, pink noise, or a sine wave with added white noise. Based on their ability to differentiate the level of complexity in the three different generated signal types, and their sensitivity and parameter consistency, MSE and RCMSE were deemed most appropriate. These two algorithms were applied to …

On The Calculation Of Sample Entropy Using Continuous And Discrete Human Gait Data, John D. Mccamley, William Denton, Peter C. Raffalt, Jennifer M. Yentes

Journal Articles

Sample entropy (SE) has relative consistency using biologically-derived, discrete data >500 data points. For certain populations, collecting this quantity is not feasible and continuous data has been used. The effect of using continuous versus discrete data on SE is unknown, nor are the relative effects of sampling rate and input parameters m (comparison vector length) and r(tolerance). Eleven subjects walked for 10-minutes and continuous joint angles (480 Hz) were calculated for each lower-extremity joint. Data were downsampled (240, 120, 60 Hz) and discrete range-of-motion was calculated. SE was quantified for angles and range-of-motion at all sampling rates and multiple combinations …

Stride-To-Stride Fluctuations In Transtibial Amputees Are Not Affected By Changes In Push-Off Mechanics From Using Different Prostheses, Chase G. Rock, Shane R. Wurdeman, Nikolas Stergiou, Kota Z. Takahashi

Journal Articles

Stride-to-stride fluctuations of joint kinematics during walking reflect a highly structured organization that is characteristic of healthy gait. The organization of stride-to-stride fluctuations is disturbed in lower-limb prosthesis users, yet the factors contributing to this difference are unclear. One potential contributor to the changes in stride-to-stride fluctuations is the altered push-off mechanics experienced by passive prosthesis users. The purpose of our study was to determine if changes in push-off mechanics affect stride-to-stride fluctuations in transtibial amputees. Twenty-two unilateral transtibial amputees were enrolled in the 6- week cross-over study, where High and Low Activity (based on the Medicare Functional Classification System) …

Quantification Of Daily Physical Activity And Sedentary Behavior Of Claudicating Patients, Hernan Hernandez, Sara A. Myers, Molly Schieber, Duy M. Ha, Sarah Baker, Panagiotis Koutakis, Kyung-Soo Kim, Constance Mietus, George P. Casale, Iraklis Pipinos

Journal Articles

Background

Methods

A Novel And Safe Approach To Simulate Cutting Movements Using Ground Reaction Forces, Amelia Lanier, Brian Knarr, Nicholas Stergiou, Thomas S. Buchanan

Journal Articles

Control of shear ground reaction forces (sGRF) is important in performing running and cutting tasks as poor sGRF control has implications for those with knee injuries, such as anterior cruciate ligament (ACL) ruptures. The goal of this study was to develop a novel and safe task to evaluate control or accurate modulation of shear ground reaction forces related to those generated during cutting. Our approach utilized a force control task using real-time visual feedback of a subject’s force production and evaluated control capabilities through accuracy and divergence measurements. Ten healthy recreational athletes completed the force control task while force control …

Exoskeleton Assistance Symmetry Matters: Unilateral Assistance Reduces Metabolic Cost, But Relatively Less Than Bilateral Assistance, Philippe Malcolm, Samuel Galle, Pieter Van Den Berghe, Dirk De Clercq

Journal Articles

Background: Many gait impairments are characterized by asymmetry and result in reduced mobility. Exoskeletons could be useful for restoring gait symmetry by assisting only one leg. However, we still have limited understanding of the effects of unilateral exoskeleton assistance. Our aim was to compare the effects of unilateral and bilateral assistance using a within-subject study design.

Methods: Eleven participants walked in different exoskeleton conditions. In the Unilateral conditions, only one leg was assisted. In Bilateral Matched Total Work, half of the assistance from the Unilateral conditions was applied to both legs such that the bilateral sum was equal …

Entraining Chaotic Dynamics: A Novel Movement Sonification Paradigm Could Promote Generalization, Dobromir Dotov, Tom Froese

Journal Articles

Tasks encountered in daily living may have instabilities and more dimensions than are sampled by the senses such as when carrying a cup of coffee and only the surface motion and overall momentum are sensed, not the fluid dynamics. Anticipating non-periodic dynamics is difficult but not impossible because mutual coordination allows for chaotic processes to synchronize to each other and become periodic. A chaotic oscillator with random period and amplitude affords being stabilized onto a periodic trajectory by a weak input if the driver incorporates information about the oscillator. We studied synchronization with predictable and unpredictable stimuli where the unpredictable …