Biomechanics Commons^™

Peripheral Arterial Disease Affects The Frequency Response Of Ground Reaction Forces During Walking, Denise Mcgrath, Timothy N. Judkins, Iraklis Pipinos, Jason Johanning

Journal Articles

Background—Walking is problematic for patients with Peripheral Arterial Disease. The purpose of this study was to investigate the frequency domain of the ground reaction forces during walking to further elucidate the ambulatory impairment of these patients.

Methods—Nineteen bilateral peripheral arterial disease patients and nineteen controls were included in this study. Subjects were matched for age and gait speed. Participants walked over a force plate sampling at 600Hz. PAD patients were tested before (pain-free condition) after the onset of claudication symptoms (pain). We calculated median frequency, frequency bandwidth, and frequency containing 99.5% of the signal for the vertical and …

Path Integration: Effect Of Curved Path Complexity And Sensory System On Blindfolded Walking, Panagiotis Koutakis, Mukul Mukherjee, Srikant Vallabhajosula, David J. Blanke, Nikolaos Stergiou

Journal Articles

Path integration refers to the ability to integrate continuous information of the direction and distance traveled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately …

Patients With Peripheral Arterial Disease Exhibit Reduced Joint Powers Compared To Velocity-Matched Controls, Shane R. Wurdeman, Panagiotis Koutakis, Sara A. Myers, Jason Johanning, Iraklis Pipinos, Nikolaos Stergiou

Journal Articles

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance ( …

Patients With Peripheral Arterial Disease Exhibit Reduced Joint Powers Compared To Velocity-Matched Controls, Shane Wurdeman, Panagiotis Koutakis, Sara Myers, Jason Johanning, Iraklis Pipinos, Nicholas Stergiou

Journal Articles

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance ( …

Wearing A Safety Harness During Treadmill Walking Influences Lower Extremity Kinematics Mainly Through Changes In Ankle Regularity And Local Stability, Leslie M. Decker, Fabien Cignetti, Nikolaos Stergiou

Journal Articles

Background: Wearing a harness during treadmill walking ensures the subject’s safety and is common practice in biomedical engineering research. However, the extent to which such practice influences gait is unknown. This study investigated harness-related changes in gait patterns, as evaluated from lower extremity kinematics during treadmill walking.

Findings: Healthy subjects (n = 10) walked on a treadmill at their preferred speed for 3 minutes with and without wearing a harness (LiteGait®, Mobility Research, Inc.). In the former condition, no weight support was provided to the subjects. Lower extremity kinematics was assessed in the sagittal plane from the mean (meanRoM), standard …

Variability Of Gait Is Dependent On Direction Of Progression: Implications For Active Control, Shane R. Wurdeman, Neil B. Huben

Journal Articles

Typical healthy walking displays greater variability in the mediolateral direction compared to the anteroposterior direction. This greater variability is thought to represent increased uncertainty in movement. As a result, it has been postulated that the mediolateral direction of gait requires more active control by the central nervous system while the anteroposterior direction is controlled through passive actions. However, this theory has only been tested on gait where progression occurs in the anteroposterior direction. Therefore, the purpose of this study was to investigate how the amount of variability is affected if progression occurs in the mediolateral direction using a lateral stepping …

Walk-Run Transition Speed And The Relevance Of Loading, Muscular Fatigue, And Human Kinematics: A Comparison Of Human Gait Patterns, Callie Elizabeth Gunderson

Boise State University Theses and Dissertations

INTRODUCTION: The walk-to-run transition (WRT) typically occurs at a preferred transition speed (PTS) of 1.9-2.1ms^-1. Previous research has focused on potential triggers for this transition such as leg length, muscular fatigue, loading rates (LR), and vertical ground reaction forces (VGRFs). Rather than focus on mechanisms responsible for the transition, the purpose of the current study was to determine if basic anthropometrics or gait characteristics are predictive of the WRT. METHODS: Thirty participants were recruited for the current study (n = 13 male, 17 female; n = 11 normal weight, n = 10 overweight, n = …

The Influence Of Visual Perception Of Self-Motion On Locomotor Adaptation To Unilateral Limb Loading, Mukul Mukherjee, K.-C. Siu, Dimitrios Kastavelis, Pierre B. Fayad, Nikolaos Stergiou

Journal Articles

Self-perception of motion through visual stimulation may be important for adapting to locomotor conditions. Unilateral limb loading is a locomotor condition that can improve stability and reduce abnormal limb movement. In the present study, the authors investigated the effect of self-perception of motion through virtual reality (VR) on adaptation to unilateral limb loading. Healthy young adults, assigned to either a VR or a non-VR group, walked on a treadmill in the following 3 locomotor task periods—no load, loaded, and load removed. Subjects in the VR group viewed a virtual corridor during treadmill walking. Exposure to VR reduced cadence and muscle …

Multiple Sclerosis Affects The Frequency Content In The Vertical Ground Reaction Forces During Walking, Shane R. Wurdeman, Jessie M. Huisinga, Mary Filipi, Nikolaos Stergiou

Journal Articles

Background: Multiple sclerosis is a progressive neurological disease that results in a high incident of gait disturbance. Exploring the frequency content of the ground reaction forces generated during walking may provide additional insights to gait in patients with multiple sclerosis that could lead to specific tools for differential diagnosis. The purpose of this study was to investigate differences in the frequency content of these forces in an effort to contribute to improved clinical management of this disease.

Methods: Eighteen patients and eighteen healthy controls walked across a 10 meter long walkway. The anterior–posterior and vertical ground reaction forces generated …

Walking Abnormalities Are Associated With Copd: An Investigation Of The Nhanes Iii Dataset, Jenna M. Yentes, Harlan Sayles, Jane Meza, David M. Mannino, Stephen I. Rennard, Nikolaos Stergiou

Journal Articles

Research on the peripheral effects of COPD has focused on physiological and structural changes. However, different from muscular weakness or decreased physical activity, mechanical abnormalities of the muscular system, e.g. walking, have yet to be investigated. Our purpose was to utilize the National Health and Nutritional Examination Survey (NHANES) dataset to determine whether walking abnormalities are associated with COPD severity. To determine if walking abnormalities were independently associated with COPD severity, our analysis aimed to investigate the association of physical activity levels with COPD severity and with walking abnormalities. The NHANES III dataset that contains data for 31,000 persons that …

Impact Of Resistance Training On Balance And Gait In Multiple Sclerosis, Mary Filipi, M. Patricia Leuschen, Jessie M. Huisinga, Lorene Schmaderer, Jeanna Vogel, Daryl Kucera, Nikolaos Stergiou

Journal Articles

Multiple sclerosis (MS) is an incurable neurodegenerative disease whose symptoms are only partially relieved by pharmaceutical intervention. Disability due to this disease process can impede activities of daily living and decrease quality of life, both for MS patients and for their care partners and families. A nonrandomized, nonblinded prospective cohort study of 45 patients with MS was undertaken to investigate the impact of an exercise program emphasizing resistance training on balance and gait. This article presents data for the first 33 participants to complete the study protocol. The exercise program consisted of twice-weekly 50-minute sessions for 6 months. At 3 …

Attractor Divergence As A Metric For Assessing Walking Balance, Max J. Kurz, Katerina Markopoulou, Nikolaos Stergiou

Journal Articles

: Individuals with Parkinson's disease and the aged have a high prevalence of falls. Since an increase in the number of falls is associated with physical and psychological harm, it is prudent that biomechanical metrics be established that will accurately assess an individual's walking balance. In this investigation, we initially used a simple bipedal walking computer model to theoretically establish the relationship between attractor divergence and walking balance. The Lyapunov exponent was used to quantify the amount of divergence present in the walking attractor. Simulations from our model indicated that attractors that have a greater amount of divergence are more …

Joint Torques And Powers Are Reduced During Ambulation For Both Limbs In Patients With Unilateral Claudication, Panagiotis Koutakis, Iraklis Pipinos, Sara A. Myers, Nikolaos Stergiou, Thomas G. Lynch, Jason Johanning

Journal Articles

Objectives: Symptomatic peripheral arterial disease (PAD) results in significant gait impairment. In an attempt to fully delineate and quantify these gait alterations, we analyzed joint kinematics, torques (rotational forces), and powers (rotational forces times angular velocity) in patients with PAD with unilateral claudication for both the affected and nonaffected legs.

Methods: Twelve patients with unilateral PAD (age, 61.69 ± 10.53 years, ankle-brachial index [ABI]: affected limb 0.59 ± 0.25; nonaffected limb 0.93 ± 0.12) and 10 healthy controls (age, 67.23 ± 12.67 years, ABI >1.0 all subjects) walked over a force platform to acquire gait kinetics, while joint kinematics were …

Complexity And Human Gait, Leslie M. Decker, Fabien Cignetti, Nikolaos Stergiou

Journal Articles

Recently, the complexity of the human gait has become a topic of major interest within the field of human movement sciences. Indeed, while the complex fluctuations of the gait patterns were, for a long time, considered as resulting from random processes, the development of new techniques of analysis, so-called nonlinear techniques, has open new vistas for the understanding of such fluctuations. In particular, by connecting the notion of complexity to the one of chaos, new insights about gait adaptability, unhealthy states in gait and neural control of locomotion were provided. Through methods of evaluation of the complexity, experimental results obtained …

Anterior Cruciate Ligament Reconstruction Results In Alterations In Gait Variability, Constantina O. Moraiti, Nikolaos Stergiou, Haris S. Vasiliadis, Eustathios Motsis, Anastasios D. Georgoulis

Journal Articles

Introduction: The temporal structure of gait variability has shown that healthy human gait exhibits long- range correlations and deterministic properties which allow the neuromuscular system to be flexible and adaptable to stresses. Pathology results in deterioration of these properties. We examined structure of gait variability after ACL reconstruction with either BPTB or quadrupled ST/G tendon autografts.

Methods: Six patients with BPTB reconstruction, six with ST/G reconstruction and six healthy controls walked on a treadmill at their self-selected pace. Two minutes of continuous kinematic data were recorded with a 6-camera optoelectronic system. The nonlinear measure of the largest Lyapunov …

Lyapunov Exponent And Surrogation Analysis Of Patterns Of Variability: Profiles In New Walkers With And Without Down Syndrome, Beth A. Smith, Nikolaos Stergiou, Beverly D. Ulrich

Journal Articles

In previous studies we found that preadolescents with Down syndrome (DS) produce higher amounts of variability (Smith et al., 2007) and larger Lyapunov exponent (LyE) values (indicating more instability) during walking than their peers with typical development (TD) (Buzzi & Ulrich, 2004). Here we use nonlinear methods to examine the patterns that characterize gait variability as it emerges, in toddlers with TD and with DS, rather than after years of practice. We calculated Lyapunov exponent (LyE) values to assess stability of leg trajectories. We also tested the use of 3 algorithms for surrogation analysis to investigate mathematical periodicity of toddlers’ …

Peripheral Arterial Disease Affects Kinematics During Walking, Ronaldo Celis, Iraklis Pipinos, Melissa Scott-Pandorf, Sara A. Myers, Nikolaos Stergiou, Jason Johanning

Journal Articles

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD) producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical analysis to characterize the kinematic ambulatory pattern of claudicating patients. We hypothesized that compared with control subjects, claudicating patients have altered kinematic gait patterns that can be fully characterized utilizing advanced biomechanical analysis.

Methods: The study examined fourteen PAD patients (age: 58 ± 3.4 years; weight: 80.99 ± 15.64 kg) with clinically diagnosed femoro-popliteal occlusive disease (Ankle Brachial Index (ABI): 0.56 ± 0.03, range 0.45 to 0.65) and five healthy controls (age: 53 ± …

Aging And Partial Body Weight Support Affects Gait Variability, Anastasia Kyvelidou, Max J. Kurz, Julie L. Ehlers, Nikolaos Stergiou

Journal Articles

Background: Aging leads to increases in gait variability which may explain the large incidence of falls in the elderly. Body weight support training may be utilized to improve gait in the elderly and minimize falls. However, before initiating rehabilitation protocols, baseline studies are needed to identify the effect of body weight support on elderly gait variability. Our purpose was to determine the kinematic variability of the lower extremities in young and elderly healthy females at changing levels of body weight support during walking.

Methods: Ten young and ten elderly females walked on a treadmill for two minutes with a body …

Peripheral Arterial Disease Affects Ground Reaction Forces During Walking, Melissa Scott-Pandorf, Nikolaos Stergiou, Jason Johanning, Leon Robinson, Thomas G. Lynch, Iraklis Pipinos

Journal Articles

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The gait of claudicating patients has been evaluated using primarily temporal and spatial parameters. With the present study, we used advanced biomechanical measures to further delineate the ambulatory impairment of claudicating patients. We hypothesized that the claudicating legs of PAD patients have an altered kinetic gait pattern compared with normal legs from control subjects.

Methods: Ambulation kinetics (ground reaction forces) were evaluated in claudicating patients and compared with age-matched healthy controls. Forces were analyzed in the vertical, anterior–posterior, and medial–lateral directions. Time from heel …

Original Investigation Correlated Joint Fluctuations Can Influence The Selection Of Steady State Gait Patterns In The Elderly, Max J. Kurz, Nikolaos Stergiou

Journal Articles

This investigation utilized a Markov model to investigate the relationship of correlated lower extremity joint fluctuations and the selection of a steady state gait pattern in the young and elderly. Our model simulated the neuromuscular system by predicting the behavior of the joints for the next gait cycle based on the behavior exhibited in the preceding gait cycles. Such dependencies in the joint fluctuations have been noted previously in the literature. We speculated that compared to the young model, the characteristics of the correlated fluctuations in the elderly model would result in the selection of a different steady state gait …

The Locomotor Kinematics Of Asian And African Elephants: Changes With Speed And Size, John R. Hutchinson, Delf Schwerda, Daniel J. Famini, Robert H.I. Dale, Martin S. Fischer, Rodger Kram

Scholarship and Professional Work - LAS

For centuries, elephant locomotion has been a contentious and confusing challenge for locomotion scientists to understand, not only because of technical difficulties but also because elephant locomotion is in some ways atypical of more familiar quadrupedal gaits. We analyzed the locomotor kinematics of over 2400 strides from 14 African and 48 Asian elephant individuals (body mass 116-4632 kg) freely moving over ground at a 17-fold range of speeds, from slow walking at 0.40 m s^-1 to the fastest reliably recorded speed for elephants, 6.8 m s^-1. These data reveal that African and Asian elephants have some subtle …

An Improved Surrogate Method For Detecting The Presence Of Chaos In Gait, David J. Miller, Nikolaos Stergiou, Max J. Kurz

Journal Articles

It has been suggested that the intercycle variability present in the time series of biomechanical gait data is of chaotic nature. However, the proper methodology for the correct determination of whether intercycle fluctuations in the data are deterministic chaos or random noise has not been identified. Our goal was to evaluate the pseudoperiodic surrogation (PPS) [Small et al., 2001. Surrogate test for pseudoperiodic time series data. Physical Review Letters 87(18), 188,101–188,104], and the surrogation algorithms of Theiler et al. [1992. Testing for nonlinearity in time series: the method of surrogate data. Physica D 58(1–4), 77–94] and of Theiler and Rapp …

An Artificial Neural Network That Utilizes Hip Joint Actuations To Control Bifurcations And Chaos In A Passive Dynamic Bipedal Walking Model, Max J. Kurz, Nikolaos Stergiou

Journal Articles

Chaos is a central feature of human locomotion and has been suggested to be a window to the control mechanisms of locomotion. In this investigation, we explored how the principles of chaos can be used to control locomotion with a passive dynamic bipedal walking model that has a chaotic gait pattern. Our control scheme was based on the scientific evidence that slight perturbations to the unstable manifolds of points in a chaotic system will promote the transition to new stable behaviors embedded in the rich chaotic attractor. Here we demonstrate that hip joint actuations during the swing phase can provide …

The Effect Of Anterior Cruciate Ligament Recontruction On Lower Extremity Relative Phase Dynamics During Walking And Running, Max J. Kurz, Nikolaos Stergiou, Ugo H. Buzzi, Anastasios D. Georgoulis

Journal Articles

The purpose of this investigation was to use relative phase dynamics to evaluate gait in individuals with a reconstructed anterior cruciate ligament (ACL) during walking and running. Relative phase dynamics can describe the coordination strategies between the interacting segments at the lower extremity. Ten subjects who had undergone ACL reconstruction using the central third of their patellar tendon and ten healthy controls walked and ran on a treadmill at a self-selected pace. Relative phase dynamics were calculated for the foot–shank and shank–thigh coordinative relation- ships. Statistical differences between the groups were noted for the foot– shank relationship (p<0.05) during both walking and running and for the shank–thigh relationship (p<0.05) during walking. Our results indicate that current ACL reconstructive techniques may result in altered relative phase dynamics. These changes in relative phase dynamics could be related to a loss of sensory information about joint position and velocity that is typically provided by the intact ACL. Additionally, relative phase adaptations could be a learned response from the early stages of postsurgical rehabilitation. Relative phase dynamics provide quantitative information about the dynamic status of the ACL-reconstructed knee that cannot be gained from the conventional time-series evaluation of gait analysis data. Relative phase dynamics measures should supplement the conventional gait analysis measures that are used today for the clinical evaluation of the functional dynamic stability of the reconstructed knee. The examination of relative phase dynamics could be clinically important for the quantification of new ACL surgical interventions and of patient performance at various stages of rehabilitation. Further research should incorporate relative phase dynamics to understand the influence of ACL reconstruction on coordination and functional patient outcomes.

A Template For The Exploration Of Chaotic Locomotive Patterns, Max J. Kurz, Nikolaos Stergiou, Jack Heidel, E. Terry Foster

Journal Articles

Inverted pendulum and spring-mass models have been successfully used to explore the dynamics of the lower extremity for animal and human locomotion. These models have been classified as templates that describe the biomechanics of locomotion. A template is a simple model with all the joint complexities, muscles and neurons of the locomotor system removed. Such templates relate well to the observed locomotive patterns and provide reference points for the development of more elaborate dynamical systems. In this investigation, we explored if a passive dynamic double pendulum walking model, that walks down a slightly sloped surface (γγ was increased, …

Walking And Running In The Red-Legged Running Frog, Kassina Maculata, Anna N. Ahn, E Furrow, Andrew A. Biewener

All HMC Faculty Publications and Research

Although most frog species are specialized for jumping or swimming, Kassina maculata (red-legged running frog) primarily uses a third type of locomotion during which the hindlimbs alternate. In the present study, we examined Kassina's distinct locomotory mode to determine whether these frogs walk or run and how their gait may change with speed. We used multiple methods to distinguish between terrestrial gaits: the existence or absence of an aerial phase, duty factor, relative footfall patterns and the mechanics of the animal's center of mass (COM). To measure kinematic and kinetic variables, we recorded digital video as the animals moved …

The Aging Human Neuromuscular System Expresses Less Certainty For Selecting Joint Kinematics During Gait, Max J. Kurz, Nikolaos Stergiou

Journal Articles

This investigation quantitatively characterized the certainty of the aging neuromuscular system in selecting a joint range of motion during gait based on the statistical concept of entropy. Elderly and young control groups walked on a treadmill at a self-selected pace. Joint angles were calculated for the ankle, knee and hip. We hypothesized that the aging group would exhibit less certainty in selecting a joint range of motion during gait. Our results supported this hypothesis, and indicated that aged individuals demonstrated statistically less certainty for the knee (16.8%) and hip (24.6%). We suggest that neurophysiological changes associated with aging may result …

The Relationship Of Foot Types To Pressure Distribution Patterns Of The Forefoot During Gait, Hui-Ji Fan

Rehabilitation Sciences Theses & Dissertations

Pressure distribution under the foot has been considered a useful indicator in the treatment of foot problems. The purpose of this study was to determine the relationship between foot types and pressure patterns under the forefoot. Fifty-four healthy subjects (19 males, 35 females, mean age=27 years, S0=4, range=21-39) participated in this study. A BTE pedobarograph was used to record pressure distribution under the foot during barefoot walking. Foot types were classified as neutral, pronated, and supinated. Pressure distribution under the forefoot was classified as medial, central, and lateral patterns. The medial pattern had the highest peak pressure under the first …

Data On Gait Characteristics Of Four, Five, And Six Year Old Children Using Three Dimensional Video Motion Analysis, Donna Soave Nichols

Rehabilitation Sciences Theses & Dissertations

The purpose of this study resulted from a need to gather and analyze data on gait characteristics of normal children using the Peak Performance Technologies, Incorporated system, initiate a data base for the Motion Analysis Center at Old Dominion University and compare a computerized motion analysis system to studies using different methods. Fifteen children, aged four to six, were evaluated during gait using a video-based computerized motion analysis system manufactured by Peak Performance Technologies, Incorporated. The gait characteristics studied were stride length, cadence, angular displacements and angular velocities of the pelvis, hips, knees and ankles. The results showed that methods …