Life Sciences Commons^™

Reliability And Validity Of Knee Moments: 3d Gait Analysis In Subjects With And Without Knee Osteoarthritis, Sara E. Richardson

Electronic Thesis and Dissertation Repository

Quantifying the reliability and validity of gait data in patients with knee osteoarthritis is required to more confidently evaluate effects of interventions and identify potential responders. 109 patients after high tibial osteotomy underwent 3-dimensional gait analysis consisting of four walking trials to calculate the external knee moments in three anatomical planes. The first two trials were compared to the second two trials to evaluate within-session test re-test reliability. 61 patients were matched to 61 healthy controls of similar age, sex and body mass index. Intraclass correlation coefficients were very high, ranging from 0.93 for peak knee adduction moment to 0.84 …

Neuromuscular Function Following Lengthening Contractions, Geoffrey A. Power

Electronic Thesis and Dissertation Repository

Unaccustomed lengthening contractions have been shown to impair muscle function - however little is known regarding this impairment on muscle power - specifically, the velocity component of power during voluntary contractions in humans. The four studies presented in my thesis investigated power-loss following lengthening contractions in healthy young and old women and young men.

The purpose of Study 1 was to determine reliability of velocity-dependent power of the dorsiflexors using the isotonic mode of the Biodex Dynamometer. I determined the isotonic mode is reliable and can be used to track changes in velocity and power following fatigue and lengthening contractions. …

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 …

External Work Is Deficient In Both Limbs Of Patients With Unilateral Pad, Shane R. Wurdeman, Sara A. Myers, Jason Johanning, Iraklis Pipinos, Nikolaos Stergiou

Journal Articles

External work was utilized to measure differences between the unaffected and the affected limb in patients with unilateral peripheral arterial disease compared to healthy controls. Patients with unilateral peripheral arterial disease have shown deficits in peak joint powers during walking in the unaffected and affected legs. However, no research has detailed the amount of work that is being performed by each leg compared to healthy controls even though such an analysis would provide valuable information on the energy output from the affected and the unaffected legs. Two hypotheses were tested: a) the unaffected and affected leg would perform less work …

Sensitivity Of The Wolf’S And Rosenstein’S Algorithms To Evaluate Local Dynamic Stability From Small Gait Data Sets: Response To Commentaries By Bruijn Et Al., Fabien Cignetti, Leslie M. Decker, Nikolaos Stergiou

Journal Articles

Assessing gait stability using the Largest Lyapunov Exponent (λ₁) has become popular, especially because it may be a key measure in evaluating gait abnormalities in patient populations. However, clinical settings usually involve having small gait data sets and accurate determination of λ₁ estimates from such sets is difficult. In an effort to address this issue, Cignetti et al.2 recently identified that λ₁ estimates using the algorithm of Wolf et al.9 (W-algorithm) were more sensitive than those using the algorithm of Rosenstein et al.7 (R-algorithm) in order to capture age-related …

Frictional Forces Of A Fixed, Esthetic Orthodontic Appliance System, Brady Michael Nance

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: The demands of an all esthetic fixed orthodontic appliance system are ever increasing in today's world. Frictional values of an esthetic, fixed orthodontic appliance system are needed to evaluate their clinical effectiveness for orthodontic treatment. The aim of this study is to evaluate the frictional values of various esthetic orthodontic archwires ligated to an esthetic orthodontic bracket.

Methods: Three types of stainless steel and nickel titanium alloy (niti) esthetic orthodontic archwires (epoxy, poly, plastic) in four sizes (.016, .018, .017 x .025, .019 x .025 inches) were ligated to both a stainless steel bracket system and a ceramic (esthetic) …

Shock Attenuation In Landing, Bryon Christopher Applequist

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shock attenuation (SA) has been well studied in activities such as walking and running (Chu, et al. 2004; Derrick, et al. 2004; Mercer, et al. 2003); however, there is a lack of research regarding SA during landing. Furthermore, there is lack of information regarding which structures attenuate shock. The purpose of this study was to examine SA among the leg-hip, hip-head, and leg-head segments during landing. Each subject (n=10, Age 26.3 ± 2.71 years, Height 1.68 ± 0.08 m, Mass 70.49 ± 16.03 kg) was instrumented with accelerometers at the leg, hip and forehead. Subjects then performed landings from three …

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

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 600 Hz. 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 …

Hamstring-Dominant Strategy Of The Bone–Patellar Tendon–Bone Graft Anterior Cruciate Ligament–Reconstructed Leg Versus Quadriceps-Dominant Strategy Of The Contralateral Intact Leg During High-Intensity Exercise In Male Athletes, Kostas Patras, Franceska Zampeli, Stavros Ristanis, Elias Tsepis, Giorgos Ziogas, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Purpose

The purpose of this study was to investigate the effect of anterior cruciate ligament (ACL) reconstruction on the quadriceps-dominant strategy as a parameter associated with the neuromuscular control of the knee joint.

Methods

In this study 14 competitive soccer players who had undergone ACL reconstruction with bone–patellar tendon–bone autograft and 14 healthy competitive soccer players performed two 10-minute treadmill runs, 1 at moderate intensity and 1 at high intensity. Electromyographic recordings were acquired by use of a telemetric system at the third, fifth, seventh, and tenth minute of the runs from the vastus lateralis and the biceps femoris bilaterally. …

Mutations In Dmrt3 Affect Locomotion In Horses And Spinal Circuit Function In Mice, Lisa S. Andersson, Martin Larhammar, Fatima Memic, Hanna Wootz, Doreen Schwochow, Carl-Johan Rubin, Kalicharan Patra, Thorvaldur Arnason, Lisbeth Wellbring, Göran Hjälm, Freyja Imsland, Jessica Lynn Petersen, Molly E. Mccue, James R. Mickelson, Gus Cothran, Nadav Ahituv, Lars Roepstorff, Sofia Mikko, Anna Vallstedt, Gabriella Lindgren, Leif Andersson, Klas Kullander

Department of Animal Science: Faculty Publications

Locomotion in mammals relies on a central pattern-generating circuitry of spinal interneurons established during development that coordinates limb movement. These networks produce left–right alternation of limbs as well as coordinated activation of flexor and extensor muscles. Here we show that a premature stop codon in the DMRT3 gene has a major effect on the pattern of locomotion in horses. The mutation is permissive for the ability to perform alternate gaits and has a favorable effect on harness racing performance. Examination of wild-type and Dmrt3-null mice demonstrates that Dmrt3 is expressed in the dI6 subdivision of spinal cord neurons, takes …

Effect Of Sledge Hockey Configuration On Sledge Hockey Performance, Cliff Worden-Rogers

Electronic Thesis and Dissertation Repository

The purpose of this study was to evaluate the position of a sledge hockey player in their sledge using measurements of knee angle, seat height, and stability. Prior to this study, sledge hockey coaches and athletes used trivial methods to position a player in their seat. Proper positioning can enhance performance and function of the athlete. Nine different positions were evaluated using two on-ice sledge hockey specific tests. Four experienced male sledge hockey players from the London Blizzard who compete in the Ontario Sledge Hockey Association participated in this study. The results suggest a knee angle of 140º with a …

Net Impulse And Net Impulse Characteristics In Vertical Jumping, Satoshi Mizuguchi

Electronic Theses and Dissertations

The purpose of this dissertation was to explore the potential use of net impulse and its characteristics in vertical jumping to monitor athletes' performance status and responses/adaptations to interventions. Five variables were proposed as net impulse characteristics: net impulse height and width, rate of force development, shape factor, and net impulse proportion. The following were then examined: 1) test-retest reliability of a new approach to identify net impulse in a force-time curve and of net impulse characteristics and criterion validity of the new approach; 2) effective measures of net impulse characteristics; 3) relationships between training-induced changes in its characteristics and …

Effects Of Physical Exertion And Alignment Alterations On Trans-Tibial Amputee Gait, And Concurrent Validity Of Prosthesis-Integrated Measurement Of Gait Kinetics, Goeran Fiedler

Theses and Dissertations

This study investigated the effects of slight changes in the alignment of the artificial limb of trans-tibial amputees on the walking pattern on the level of forces and moments, particularly when physical exertion levels increase. Two alignment conditions were assessed in ten trans-tibial amputees while walking with low and with "strong" levels of exertion. Two separate data collection methods were utilized simultaneously: a conventional motion analysis, and continuous recordings from prosthesis-integrated force sensors. While the former was used to compare bilateral leg symmetry across conditions, the latter allowed analyzing unilateral step variability within subjects. This paper presents both analyses in …

Cell-Matrix Adhesion In Muscle Development And Disease, Michelle F. Goody

Electronic Theses and Dissertations

A variety of diseases, both inherited and acquired, affect muscle tissues in humans. The anchoring of muscle fibers to their surrounding environment is critical for muscle homeostasis. Muscle fibers attach to their microenvironment through cell-matrix adhesion complexes. These anchoring complexes are placed under repeated stress during muscle contraction. Genetic mutations in these complexes weaken the attachment between muscle fibers and their microenvironment, making fibers more susceptible to damage and death. This increased fiber degeneration eventually leads to progressive muscle wasting diseases, known as congenital muscular dystrophies. Although clinical trials are ongoing, there is presently no way to cure the loss …

Postural Control Strategy During Standing Is Altered In Patients With Multiple Sclerosis, Jessie M. Huisinga, Jenna M. Yentes, Mary Filipi, Nikolaos Stergiou

Journal Articles

Disturbances in balance are one of the first reported symptoms of Multiple Sclerosis (MS), yet limited research has been performed to classify the postural control deficits in this population. This study investigated the variability present in the sway patterns during quiet standing in patients with MS (PwMS) and healthy controls. Subjects were assessed (eyes open, closed) standing on a force platform. Variability of the sway patterns was quantified using a measure of amount of variability (root mean square; RMS) and two measures of temporal structure of variability (Lyapunov Exponent – LyE; Approximate Entropy – ApEn). RMS results revealed significantly higher …

Kinematics And Muscle Activation Patterns During Simulated Uphill Pedaling On An Indoor Cycle Ergometer, Benjamin Thomas Stein

Boise State University Theses and Dissertations

INTRODUCTION: An indoor cycle ergometer allows for competitive and recreational mountain bike cyclists to simulate uphill conditions with precisely controlled and monitored pedaling. While simulating an uphill condition indoors, with or without a climbing block, the cyclist body may not be in the same position as while pedaling outdoors. This possible difference in body position may have training implications. PURPOSE: The purpose of this study was to determine if there are differences in kinematics and/or muscle activation patterns while pedaling on a level surface compared to an inclined surface while pedaling on a mountain bike on an indoor cycle …

Changes In In Vivo Knee Contact Forces Through Gait Modification, Allison Kinney, Thor F. Besier, Amy Slider, Scott L. Delp, Darryl D. D'Lima, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Gait modification represents a non-invasive method for reducing knee joint loading in patients with knee osteoarthritis. Previous studies have shown that a variety of gait modifications are effective in reducing the external knee adduction moment. The external knee adduction moment is often used as a surrogate measure of medial compartment force. However, a recent study showed that reductions in the external knee adduction moment do not guarantee reductions in medial compartment loads. Therefore, direct measurement of changes in knee contact force is important for determining the effectiveness of gait modifications. A previous study found that medial thrust gait and walking …

Taking Balance Measurement Out Of The Laboratory And Into The Home: Discriminatory Capability Of Novel Centre Of Pressure Measurement In Fallers And Non-Fallers, Denise Mcgrath, Emer P. Doheny, Lorcan Walsh, David Mckeown, Clodagh Cunningham, Lisa Crosby, Rose Anne Kenny, Nikolaos Stergiou, Brian Caulfield, Barry R. Greene

Journal Articles

We investigated three methods for estimating centre of pressure excursions, as measured using a portable pressure sensor matrix, in order to deploy similar technology into the homes of older adults for longitudinal monitoring of postural control and falls risk. We explored the utility of these three methods as markers of falls risk in a cohort of 120 community dwelling older adults with and without a history of falls (65 fallers, 55 non-fallers). A number of standard quantitative balance parameters were derived using each centre of pressure estimation method. Rank sum tests were used to test for significant differences between fallers …

Effects Of Head Position And Head-Supported Mass On Nerve Function Of The Flexor Carpi Radialis Muscle In Healthy Individuals, Bethany Lauren Shivers

Graduate Theses and Dissertations

Long-term exposure to head-supported mass (HSM) has been linked with spinal degeneration including foraminal stenosis and disc deterioration. Anecdotally, HSM has also been linked to neck and arm pain and muscle atrophy, but nerve function has not been tested specifically. The combined effect of various head positions and HSM may be sufficient to compress the nerve root in aviators and Soldiers during job performance, potentially leading to short- and long-term neuromuscular effects. The Hoffmann (H) reflex, a well-established measure of nerve function, has shown to be sensitive to changes in nerve root space which occurs with different head positions. This …

The Use Of Cortisol And Hba1c As Biomarkers Of Stress In University Administrators, Jacilyn Marie Olson

Graduate Theses and Dissertations

PURPOSE: The purpose of this study was to explore the impact of perceived stress and cardiorespiratory fitness on cortisol and HbA1c, biomarkers of stress, in a group of select university administrators. The impact of gender on these relationships was of special concern. METHODS: University administrators with job titles of Chancellor, Provost, Vice Chancellors and Vice Provosts of the university, and Deans and Associate Deans at the college level were recruited. Twenty-five administrators (15 males and 10 females) agreed to participate and completed a battery of assessments that included completion of the University Administrative Concerns Questionnaire, a finger-stick blood test for …

The Effect Of Footwear On The Mechanics Of The Lower Back During Treadmill Running, Jeffrey Ray Mcclellan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Little is known regarding the effect that footwear cushioning can have on the mechanics of the low back. The purpose of this study was to 1) determine the material characteristics of a minimalist running shoe tested with and without a commercially available shoe insole, 2) determine if there are differences in lower back or knee kinematics when minimalist shoes are worn with and without a shoe insole during treadmill running, and 3) determine if there are differences in levels of muscle activation when minimalist shoes are worn with and without a shoe insole during treadmill running. Following the receipt of …

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 …

Use Of Motor Abundance In Young And Older Adults During Dual-Task Treadmill Walking, Leslie M. Decker, Fabien Cignetti, Jane F. Potter, Stephanie A. Studenski, Nikolaos Stergiou

Journal Articles

Motor abundance allows individuals to perform any task reliably while being variable in movement's particulars. The study investigated age-related differences in this feature when young adults (YA) and older adults (OA) performed challenging tasks, namely treadmill walking alone and while performing a cognitive task. A goal function for treadmill walking was first defined, i.e., maintain constant speed at each step, which led to a goal equivalent manifold (GEM) containing all combinations of step time and step length that equally satisfied the function. Given the GEM, amounts of goal-equivalent and non-goal-equivalent variability were afterwards determined and used to define an index …

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 ( …

Persons With Multiple Sclerosis Show Altered Joint Kinetics During Walking After Participating In Elliptical Exercise, Jessie M. Huisinga, Kendra K. Schmid, Mary Filipi, Nikolaos Stergiou

Journal Articles

Patients with multiple sclerosis (MS) experience abnormal gait patterns and reduced physical activity. The purpose of this study was to determine if an elliptical exercise intervention for patients with MS would change joint kinetics during gait toward healthy control values. Gait analysis was performed on patients with MS (n = 24) before and after completion of 15 sessions of supervised exercise. Joint torques and powers were calculated, while also using walking velocity as a covariate, to determine the effects of elliptical exercise on lower extremity joint kinetics during gait. Results show that elliptical exercise significantly altered joint torques at the …

Relative Roughness: An Index For Testing The Suitability Of The Monofractal Model, Vivien Marmelat, Kjerstin Torre, Didier Delignières

Journal Articles

Fractal analyses have become very popular and have been applied on a wide variety of empirical time series. The application of these methods supposes that the monofractal framework can offer a suitable model for the analyzed series. However, this model takes into account a quite specific kind of fluctuations, and we consider that fractal analyses have been often applied to series that were completely outside of its relevance. The problem is that fractal methods can be applied to all types of series, and they always give a result, that one can then erroneously interpret in the context of the monofractal …

Comparing Thigh Muscle Cross-Sectional Area And Squat Strength Among National Class Olympic Weightlifters, Power Lifters, And Bodybuilders, James J. Di Naso, Brian L. Pritschet, John D. Emmett, Jill W. Owen, Jeffrey Willardson, Travis W. Beck, Jason M. Defreitas, Fabio E. Fontana

Jeffrey Willardson

Few studies have compared anthropometric characteristics among national class athletes from different resistance training disciplines, such as Olympic Weightlifting (OL), Power Lifting (PL), and Bodybuilding (BB). Objective: The purpose of the current study was to determine if significant differences exist in the relationship between thigh muscle cross-sectional area and back squat strength among national class athletes from the sports of OL, PL, and BB. Methods: Fifteen national class athletes were assessed for back squat strength, mid-thigh circumference, and mid-thigh skinfold from which total thigh cross-sectional was estimated. A series of One-Way ANOVAs and Pearson Product Moment Correlations were used to …

Comparing Thigh Muscle Cross-Sectional Area And Squat Strength Among National Class Olympic Weightlifters, Power Lifters, And Bodybuilders, James J. Di Naso, Brian L. Pritschet, John D. Emmett, Jill W. Owen, Jeffrey Willardson, Travis W. Beck, Jason M. Defreitas, Fabio E. Fontana

Faculty Research and Creative Activity

Few studies have compared anthropometric characteristics among national class athletes from different resistance training disciplines, such as Olympic Weightlifting (OL), Power Lifting (PL), and Bodybuilding (BB). Objective: The purpose of the current study was to determine if significant differences exist in the relationship between thigh muscle cross-sectional area and back squat strength among national class athletes from the sports of OL, PL, and BB. Methods: Fifteen national class athletes were assessed for back squat strength, mid-thigh circumference, and mid-thigh skinfold from which total thigh cross-sectional was estimated. A series of One-Way ANOVAs and Pearson Product Moment Correlations were used to …

Effects Of Chainring Design On 1km Time Trial Performance Over Six Weeks In Competitive Cyclists And Triathletes (Poster), Christie O'Hara

Christie O'Hara

No abstract provided.