Biomechanics Commons^™

The Effect Of Virtual Reality On Gait Variability, Dimitrios Kastavelis, Mukul Mukherjee, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

Optic Flow (OF) plays an important role in human locomotion and manipulation of OF characteristics can cause changes in locomotion patterns. The purpose of the study was to investigate the effect of the velocity of optic flow on the amount and structure of gait variability. Each subject underwent four conditions of treadmill walking at their self-selected pace. In three conditions the subjects walked in an endless virtual corridor, while a fourth control condition was also included. The three virtual conditions differed in the speed of the optic flow displayed as follows – same speed (OFn), faster (OFf), and slower (OFs) …

Joint Moments And Powers In Healthy Young Adults During Stair Negotiation, Mira M. Momcilovic

Student Work

The primary objective of this study was to determine lower limb joint moments and powers of stair negotiation in healthy young individuals. These results will provide baseline information for future studies with elderly and clinical populations designed to prevent falls that occur during stair negotiation. In previous stair negotiation studies, researchers investigated joint moments and powers initiating stair ascent in front of the stairway. Starting farther away from the stairway allows individuals to stabilize gait velocity and thus, exclude the influence of velocity on joint moments and powers generated during stair ascent. Ten young, healthy individuals underwent gait analysis during …

An Inverse Kinematic Mathematical Model Using Groebner Basis Theory For Arm Swing Movement In The Gait Cycle, Kimberly D. Kendricks, Adam M. Fullenkamp, Robert Mcgrellis, Jonathan Juhl, Ronald F. Tuttle

Faculty Publications

Two important indicators in the gait cycle: arm swing and foot placement, when isolated, provide key information about future behaviors in the gait cycle. Through video captured data, the INSPIRE (Integration of a Sensor Package for Identifying Radical Extremists) project seeks to identify gait characteristics in arm and leg swing movement to recognize threatening individuals. In particular, one approach discussed in this paper uses Groebner Basis Theory to model arm swing movement in the gait cycle. Through inverse kinematics, joint configurations of the shoulder and elbow are found to place the wrist at a specific position and orientation in the …

The Effect Of Pharmacological Treatment On Gait Biomechanics In Peripheral Arterial Disease Patients, Jessie M. Huisinga, Iraklis Pipinos, Jason Johanning, Nikolaos Stergiou

Journal Articles

Background: Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities. Methods: Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free …

Hydrodynamic Fin Function Of Brief Squid, Lolliguncula Brevis, William J. Stewart, Ian K. Bartol, Paul S. Krueger

Biological Sciences Faculty Publications

Although the pulsed jet is often considered the foundation of a squid's locomotive system, the lateral fins also probably play an important role in swimming, potentially providing thrust, lift and dynamic stability as needed. Fin morphology and movement vary greatly among squid species, but the locomotive role of the fins is not well understood. To begin to elucidate the locomotive role of the fins in squids, fin hydrodynamics were studied in the brief squid Lolliguncula brevis, a species that exhibits a wide range of fin movements depending on swimming speed. Individual squid were trained to swim in both the …

Effects Of Varying Amounts Of Pronation On The Mediolateral Ground Reaction Forces During Barefoot Versus Shod Running, Joanna B. Morley, Leslie M. Decker, Tracy Dierks, Daniel Blanke, Jeffrey French, Nikolaos Stergiou

Journal Articles

Despite extensive research on running mechanics, there is still a knowledge gap with respect to the degree of relationship between mediolateral ground reaction forces (ML-GRF) and foot pronation. Our goal was to investigate whether differences exist in ML-GRF among runners that exhibit different degrees of pronation. Seventeen male and 13 female recreational runners ran with and without shoes while ML-GRF and frontal kinematics were collected simultaneously. Subjects were divided into groups based upon their peak eversion (low pronation, middle pronation, high pronation). Discrete parameters from the ML-GRF were peak forces, respective times of occurrence, and impulses. No significant differences were …

Evaluation Of A 3-Dimensional Inertial Tracking System For Quantifying Human Movement, David T. Delion

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to evaluate an inertial tracking unit (ITU) by comparing it to an optical tracking system. The ITU was attached to a bowling ball along with reflective markers for the optical system. Each trial started with the ball at rest on a pedestal the ball was then hung from a steel cable 10 feet long and set in motion in an elliptical pattern for approximately 25 seconds. The ball was then removed from the cable and returned to the pedestal so as to end each trial at rest. This was repeated 10 times with 5 …

Kinetics At Front Foot Contact Of Cricket Bowling During A 10-Over Spell, Jacobus Noël Liebenberg

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine what effect bowling a 10 over spell (60 balls) would have on approach velocity, vertical ground reaction forces and shock attenuation during the front foot contact of a delivery stride in cricket.

Ten Amateur cricket players (age 27±4 years, height 1.78±0.3 m, mass 80.6±8.5 kg) participated in the study. Testing was conducted at University of Nevada, Las Vegas in the Biomechanics laboratory. Participants performed a 10-over bowling spell from a 12 meter run-up. These dependent variables were measured and calculated during the bowling protocol: 1) approach velocity 2) vertical ground reaction force …

Effects Of Obesity On The Biomechanics Of Children’S Gait At Different Speeds, Philana-Lee Gouws

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of the study was to investigate the relationship between body mass index (BMI) and spatio-temporal gait characteristics of overweight/obese and non-obese school-aged children (12-14 years) at two different walking speeds. Eighty-four overweight/obese (n=28; age: 13.96 ± 0.79 yrs; mass: 74.8 ± 18.21 kg; height: 159.2 ± 7.1 cm and BMI: 29.28 ± 5.64 kg/m2) and non-obese students (n=56; age: 13.72 ± 0.79 yrs; mass: 51.7 ± 10.2 kg; height: 157.8 ± 8.3 cm and BMI: 20.69 ± 2.74 kg/m2) with no present injuries were recruited. Participants were instructed to walk across an electronic walkway in each of two …

A Biomechanical Analysis Of The Jete Dessus Using Dartfish Motion Analysis Software, Beatrice Turrubiartes

Undergraduate Research Conference

No abstract provided.

Neuromechanical Analysis Of Anterior Cruciate Ligament Risk Factors In Female Collegiate Soccer Athletes, Nelson Cortes

Human Movement Studies & Special Education Theses & Dissertations

The anterior cruciate ligament (ACL) acts in an essential role to prevent anterior tibial displacement when experiencing jump-landing forces that are applied to the lower extremity; more than 100,000 injuries per year in the United States in sport activities that often require landing, deceleration-acceleration, cutting and pivoting actions have been reported. The aim of this study was to examine the nature of any lower limb coupling differences between a drop-jump and a side-step cutting actions, assess kinematic and kinetic differences between three tasks, and evaluate the effects of two landing techniques in biomechanical risk factors while performing two unanticipated tasks. …

The Effects Of Two Different Fatigue Protocols On Lower Extremity Kinematics And Kinetics During An Unanticipated Running Stop-Jump, David L. Quammen

Human Movement Studies & Special Education Theses & Dissertations

Altered neuromuscular control strategies and biomechanical movement risk factors are most likely to contribute to the increased incidence of non-contact ACL injury for female athletes. Neuromuscular control strategies and movement patterns are further altered when the effects of fatigue are present. The purpose of this study was to determine neuromechanical differences between two fatigue protocols [Slow Linear Oxidative Fatigue Protocol (SLO-FP) and Functional Agility Short-Term Fatigue Protocol (FASTFP)] when performing a running stop-jump task (RS). A sample of convenience of fifteen Division I female soccer players (age= 19.2 ± 0.8 years; height= 1.67 ± 0.05 m; mass= 61.7 ± 8.1 …

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 …

The Ontogeny Of Muscle Structure And Locomotory Function In The Long-Finned Squid Doryteuthis Pealeii, J. T. Thompson, I. K. Bartol, A. E. Baksi, P. S. Krueger

Biological Sciences Faculty Publications

Understanding the extent to which changes in muscle form and function underlie ontogenetic changes in locomotory behaviors and performance is important in understanding the evolution of musculoskeletal systems and also the ecology of different life stages. We explored ontogenetic changes in the structure, myosin heavy chain (MHC) expression and contractile properties of the circular muscles that provide power for jet locomotion in the long-finned squid Doryteuthis pealeii. The circular muscle fibers of newly hatched paralarvae had different sizes, shapes, thick filament lengths, thin: thick filament ratio, myofilament organization and sarcoplasmic reticulum (SR) distribution than those of adults. Viewed in …

The Effects Of Two Types Of Fatigue On An Unanticipated Side-Step Cutting Task As Measured By Kinematic And Kinetic Variables, Shawn E. Lucci

Human Movement Studies & Special Education Theses & Dissertations

Fatigue has been shown to alter the neuromechanics of lower extremity. To date, no study has examined the effects of two types of fatigue on kinetics and kinematics. To determine neuromechanical differences between two fatigue protocols [Slow Linear Oxidative Fatigue Protocol (SLO-FP) and Functional Agility Short-Term Fatigue Protocol (FAST-FP)] when performing an unanticipated sidestep cutting task. Fifteen female collegiate soccer players (age=19.2±0.8 years; height=l.67±0.05m; mass=61.7±8.lkg) participated in this study. Participants were free of lower extremity injury at time of participation, and performed five successful trials of a sidestep cutting (SS) task pre and post fatigue protocols. For the SLO-FP, a …

The Effects Of An Anterior Cruciate Ligament Prevention Program And Retention Period On Lower Extremity Biomechanics, Ryan S. Mccann

Human Movement Studies & Special Education Theses & Dissertations

Researchers have attempted to determine the effects of strength, flexibility, agility, and plyometric training, as well as expert feedback on biomechanical risk factors for anterior cruciate ligament (ACL) injuries. Currently, the literature lacks information regarding athletes' ability to retain adaptations made during programs designed to reduce biomechanical risk factors for ACL injuries. The purpose of this study was to determine the effects of a 10-week strength and agility program on lower extremity kinetics and kinematics of collegiate athletes immediately following training and after a 11-week retention period. Ten NCAA Division I female soccer players free of lower extremity injury, volunteered …

A Remote Markerless Human Gait Tracking For E-Healthcare Based On Content-Aware Wireless Multimedia Communications, Haiyan Luo, Song Ci, Dalei Wu, Nikolaos Stergiou, Ka-Chun Siu

Journal Articles

Remote human motion tracking and gait analysis over wireless networks can be used for various e-healthcare systems for fast medical prognosis and diagnosis. However, most existing gait tracking systems rely on expensive equipment and take lengthy processes to collect gait data in a dedicated biomechanical environment, limiting their accessibility to small clinics located in remote areas. In this work we propose a new accurate and cost-effective e­ healthcare system for fast human gait tracking over wireless networks, where gait data can be collected by using advanced video content analysis techniques with low-cost cameras in a general clinic environment. Furthermore, based …

The Power Of Empowerment: An Icf-Based Model To Improve Self-Efficacy And Upper Extremity Function Of Survivors Of Breast Cancer, Mary Insana Fisher, Dana Howell

Physical Therapy Faculty Publications

Breast cancer is one of the most frequently diagnosed cancers among women. Breast cancer treatments often negatively impact the function of the arm, and quality of life and upper extremity function does not always return to a prediagnosis level. Survivors of breast cancer may also experience feelings of diminished self-efficacy related to functional deficits resulting from their physical limitations. The International Classification of Functioning (ICF) provides a framework for rehabilitation practitioners to address physical and psychological impairments, activity limitations, and participation restrictions. Patient outcomes may be improved by fostering self-efficacy through empowerment. This paper explores how the ICF model and …

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 …

Development Of Lower Extremity Injury Criteria And Biomechanical Surrogate To Evaluate Military Vehicle Occupant Injury During An Explosive Blast Event, Brian J. Mckay

Wayne State University Dissertations

Anti-vehicular (AV) landmines and improvised explosive devices (IED) have accounted for more than half of the United States military hostile casualties and wounded in Operation Iraqi Freedom (OIF). The lower extremity is the predominantly injured body region following an AV mine or IED blast accounting for 26 percent of all combat injuries in OIF (Owens et al., 2007). Detonations occurring under the vehicle transmit high amplitude and short duration axial loads onto the foot-ankle-tibia region of the occupant causing injuries to the lower leg. The current effort was initiated to develop lower extremity injury criteria and biofidelic biomechanical surrogate to …

The Impact Of Environmental Noise On Robot-Assisted Laparoscopic Surgical Performance, Ka-Chun Siu, I. H. Suh, Mukul Mukherjee, D. Oleynikov, Nikolaos Stergiou

Journal Articles

Background. An operating room is a noisy environment. How noise affects performance during robotic surgery remains unknown. We investigated whether noise during training with the da Vinci surgical robot (Intuitive Surgical, Inc., Sunnyvale, CA) would affect the performance of simple operative tasks by the surgeon.

Methods. Twelve medical students performed 3 inanimate operative tasks (bimanual carrying, suture tying, and mesh alignment) on the da Vinci Surgical System with or without the presence of noise. Prerecorded noise from an actual operating room was used. The kinematics of the robotic surgical instrument tips and the muscle activation patterns of the subjects were …

Variability Of Lower Extremity Joint Kinematics During Backward Walking In A Virtual Environment, Dimitrios Kastavelis, Mukul Mukherjee, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

Backward walking (BW) shows significant differences with forward walking (FW) and these differences are potentially useful in rehabilitation. However the lack of visual cues makes BW risky. The purpose of this study was to investigate the effect of visual cues provided by a virtual environment on FW and BW on gait variability. Each subject underwent four conditions of treadmill walking at self-selected pace. The subjects walked backwards in three conditions and forwards in the fourth condition. A virtual corridor was displayed to the subjects in the FW condition (forward optic flow) and two of the backward conditions (forward and backward …

Age-Related Changes In Handgrip Strength Among Healthy Indian Males And Females Aged 6-25 Years, Shyamal Koley, Sheri Melton

Kinesiology Faculty Publications

No abstract provided.

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 …

Electromyographic Analysis Of Trunk Muscle Activation During A Throwing Pattern Following Rotator Cuff Mobilization, Aubrey L. Doede

CMC Senior Theses

Correct muscular activation of the body segments during an overhand throw is achieved when movement originates in the larger and more proximal legs and trunk and moves sequentially to the smaller, distal segments of the shoulder and arm. This sequence permits angular velocity to transfer progressively through the throw as part of an open kinetic chain. The athlete can summate angular velocity and segmental forces only if he is able to create a separation between the body segments during the movement pattern, and this separation is thus essential to effective segmental sequencing for activation of the trunk muscles to occur …

Nebraska Biomechanics Core Facilty 2009 Annual Report, Issue 8, Nebraska Biomechanics Core Facility

Biomechanics Annual Report

April 2009 - March 2010

This issue features Announcements, Featured News, Projects, Collaborations, Visitors, Awards, Publications, and Support.

Nonlinear Analysis Of Ambulatory Activity Patterns In Community-Dwelling Older Adults, James T. Cavanaugh, Naomi Kochi, Nikolaos Stergiou

Journal Articles

Background The natural ambulatory activity patterns of older adults are not well understood. User-worn monitors illuminate patterns of ambulatory activity and generate data suitable for analysis using measures derived from nonlinear dynamics.

MethodsAmbulatory activity data were collected continuously from 157 community-dwelling older adults for 2 weeks. Participants were separated post hoc into groups based on the mean number of steps per day: highly active (steps ≥ 10,000), moderately active (5,000 ≤ steps < 10,000 steps), and inactive (steps

Results All groups displayed patterns of fluctuating step count values containing complex temporal structure. DFA, ER, and ApEn parameter values increased monotonically and significantly with increasing activity …

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’ …