Biomechanics Commons^™

Relationships Between Decorin And Biglycan, Structure And Tendon Mechanics Using Mutant Mouse Models, Leann Dourte

Publicly Accessible Penn Dissertations

Tendons have a complex mechanical behavior that depends on their composition and structure. Understanding structure-function relationships may elucidate important differences in the functional behaviors of specific tendons and guide targeted treatment modalities and tissue engineered constructs. Specifically, the interactions of small leucine-rich proteoglycans (SLRPs) with collagen fibrils, association with water and role in fibrillogenesis suggest that SLRPs may play an important role in tendon mechanics. Some studies have assessed the role of SLRPs in the mechanical response of tendon, but the relationships between sophisticated mechanics, assembly of collagen and SLRPs have not been well characterized. Therefore, the aim of this …

Locomotor Loading Mechanics In The Hindlimbs Of Tegu Lizards (Tupinambis Merianae): Comparative And Evolutionary Implications, K. Megan Sheffield, Michael T. Butcher, S. Katharine Shugart, Jennifer C. Gander, Richard W. Blob

Megan Sheffield

Skeletal elements are usually able to withstand several times their usual load before they yield, and this ratio is known as the bone’s safety factor. Limited studies on amphibians and non-avian reptiles have shown that they have much higher limb bone safety factors than birds and mammals. It has been hypothesized that this difference is related to the difference in posture between upright birds and mammals and sprawling ectotherms; however, limb bone loading data from a wider range of sprawling species are needed in order to determine whether the higher safety factors seen in amphibians and non-avian reptiles are ancestral …

Loading Mechanics Of The Femur In Tiger Salamanders (Ambystoma Tigrinum) During Terrestrial Locomotion, K. Megan Sheffield, Richard W. Blob

Megan Sheffield

Salamanders are often used as representatives of the basal tetrapod body plan in functional studies, but little is known about the loads experienced by their limb bones during locomotion. Although salamanders’ slow walking speeds might lead to low locomotor forces and limb bone stresses similar to those of non-avian reptiles, their highly sprawled posture combined with relatively small limb bones could produce elevated limb bone stresses closer to those of avian and mammalian species. This study evaluates the loads on the femur of the tiger salamander (Ambystoma tigrinum) during terrestrial locomotion using three- dimensional measurements of the ground reaction force …

Biomechanical Risk Factors For Knee Osteoarthritis In Young Adults: The Influence Of Obesity And Gait Instruction, Julia Ann Freedman

Doctoral Dissertations

With increasing rates of obesity, research has begun to focus of co-morbidities of obesity such as osteoarthritis. The majority of existing research has focused on older adults as the group most likely to suffer from osteoarthritis. The purpose of this study was to determine if overweight and obese young adults exhibit biomechanical risk factors for knee osteoarthritis, and to determine if young adults with biomechanical risk factors of osteoarthritis can modify these with instruction. This purpose was divided into two separate studies.

Study 1: Thirty adults between 18-35 years old were recruited into three groups according to body mass index: …

Development Of Software To Estimate Pressures On The Residual Limbs Of Amputees By Means Of A Pylon Mounted Transducer, Malli K. Yalamanchili

UNLV Theses, Dissertations, Professional Papers, and Capstones

The alignment of prosthesis has been recognized as one of the main factors that determine successful prosthetic outcomes for trans-tibial amputees. Alignment is defined as the relative position and orientation of the prosthetic components. Misalignment can result in changes in the position and orientation of the joints of the leg and moments experienced by them during gait, increases in energy use, and discomfort or even tissue breakdown at the socket/stump interface. Hence it is very important to align the prosthesis in correct manner. Gait analysis can be used to examine the effects of incorrect alignment of the prosthesis during gait. …

Stride-To-Stride Variability Is Altered During Backward Walking In Anterior Cruciate Ligament Deficient Patients, Franceska Zampeli, Constantina Moraiti Moraiti, Sofia Xergia, Vasilios Tsiaras, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Background: Recently backward walking is used by physical therapists to strengthen the hamstring muscles and thus improve the function of the knee joint of anterior cruciate ligament deficient patients. The aim of this study was to examine the stride-to-stride variability of anterior cruciate ligament deficient patients during backward walking. The variation of how a motor behavior emerges in time is best captured by tools derived from nonlinear dynamics, for which the temporal sequence in a series of values is the facet of interest.

Methods: Fifteen patients with unilateral anterior cruciate ligament deficiency and eleven healthy controls walked backwards …

A Comparison Of Interventions For Children With Cerebral Palsy To Improve Sitting Postural Control: A Clinical Trial, Regina T. Harbourne, Sandra L. Willett, Anastasia Kyvelidou, Joan E. Deffeyes, Nikolaos Stergiou

Journal Articles

Background The ability to sit independently is fundamental for function but delayed in infants with cerebral palsy (CP). Studies of interventions directed specifically toward sitting in infants with CP have not been reported.

Objective The purpose of this study was to compare 2 interventions for improving sitting postural control in infants with CP.

Design For this randomized longitudinal study, infants under 2 years of age and at risk for CP were recruited for intervention directed toward sitting independence.

Setting The intervention was conducted at home or at an outpatient facility.

Patients and Intervention Fifteen infants with typical development (mean age …

Femoral Loading Mechanics In Virginia Opossums (Didelphis Virginiana): Torsion And Mediolateral Bending In Mammalian Parasagittal Locomotion, William Gosnell

All Theses

Studies of limb bone loading in terrestrial mammals have typically found anteroposterior bending to be the primary loading regime, with torsion contributing minimally. However, previous studies have focused on large, cursorial eutherian species in which the limbs are held essentially upright. Recent in vivo strain data from the Virginia opossum Didelphis virginiana, a marsupial that uses a crouched rather than upright limb posture, have indicated that its femur experiences moderate torsion during locomotion as well as strong mediolateral bending. The elevated femoral torsion and strong mediolateral bending observed in opossums (compared to other mammals) might result from external forces such …

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

Journal Articles

Music is often played in the operating room to increase the surgeon’s concentration and to mask noise. It could have a beneficial effect on surgical performance. Ten participants with limited experience with the da Vinci robotic surgical system were recruited to perform two surgical tasks: suture tying and mesh alignment when classical, jazz, hip-hop, and Jamaican music were presented. Kinematics of the instrument tips of the surgical robot and surface electromyography of the subjects were recorded. Results revealed that a significant music effect was found for both tasks with decreased time to task completion (P = .005) and total …

Gait Variability Patterns Are Altered In Healthy Young Individuals During The Acute Reperfusion Phase Of Ischemia-Reperfusion, Sara A. Myers, Nikolaos Stergiou, Iraklis Pipinos, Jason Johanning

Journal Articles

Background

The role of ischemia reperfusion contributing to functional impairment in lower extremity peripheral arterial disease (PAD) patients has not previously been elucidated. The evaluation of gait variability patterns has proven useful in many pathologic populations. Therefore, the purpose of this study is to isolate and determine the specific effect of the acute reperfusion phase of ischemia-reperfusion on gait variability in young individuals with no vascular disease.

Materials and Methods

Thirty healthy young individuals walked on a treadmill during baseline and the acute reperfusion phase of ischemia-reperfusion conditions while lower extremity joint kinematics were captured. Stride to stride variability was …

Acl Reconstructed Patients With A Bptb Graft Present An Impaired Vastus Lateralis Neuromuscular Response During High Intensity Running, Kostas Patras, Giorgos Ziogas, Stavros Ristanis, Elias Tsepis, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

The purpose of the present study was to investigate whether the electromyographic response of the vastus lateralis (VL) muscle in the anterior cruciate ligament (ACL) reconstructed leg is similar to that of the intact contralateral leg and healthy controls, during moderate and high intensity running. Fourteen bone–patellar tendon–bone (BPTB) ACL reconstructed amateur soccer players and fourteen healthy control amateur soccer players volunteered to participate in the study. Electromyographic (EMG) traces from the vastus lateralis (VL) muscle were collected bilaterally, as athletes ran on a treadmill for 10 min on separate occasions, at moderate and high intensity. The dependent variable examined …

Severity And Characteristics Of Developmental Delay Can Be Assessed Using Variability Measures Of Sitting Posture, Anastasia Kyvelidou, Regina T. Harbourne, Nikolaos Stergiou

Journal Articles

Purpose: We sought to identify measures of variability from sitting postural sway that are significantly different among infants who were developing typically, those who were developmentally delayed or hypotonic, and those who later on had a diagnosis of spastic or athetoid cerebral palsy.

Methods: Sixty-five infants were evaluated when they were just developing the ability to sit upright by assessing center of pressure (COP) data, using measures of both amount and temporal organization of COP variability.

Results: The results indicated that measures of variability of COP could discriminate between infants with developmental delay and infants with cerebral palsy and add …

Reliability Of Center Of Pressure Measures For Assessing The Development Of Sitting Postural Control In Infants With Or At Risk Of Cerebral Palsy, Anastasia Kyvelidou, Regina T. Harbourne, Valerie K. Shostrom, Nikolaos Stergiou

Journal Articles

Objective

To establish the test-retest reliability of linear and nonlinear measures, including intra- and intersession reliability, when used to analyze the center of pressure (COP) time series during the development of infant sitting postural control in infants with or at risk for cerebral palsy (CP).

Design

Longitudinal study.

Setting

University hospital laboratory.

Participants

Infants with or at risk for CP (N=18; mean age ± SD at entry into the study, 13.7±3.6mo).

Interventions

Not applicable.

Main Outcome Measures

Infant sitting COP data were recorded for 3 trials at each session (2 sessions for each month within 1 week) for 4 consecutive …

Response To Chastin Et Al.: Analysis Of Nonlinear Patterns Of Activity, James T. Cavanaugh, Nicholas Stergiou

Journal Articles

We appreciate the thoughtful commentary by Chastin and colleagues regarding our recent article entitled “Nonlinear Analysis of Ambulatory Activity Patterns in Community-dwelling Older Adults.” (1) We fully agree with their observation that the application of nonlinear analytical tools to accelerometry data is an emerging area of research that shows potential for illuminating the complex nature of physical activity profiles. We also welcome the opportunity to discuss their concerns regarding (a) our application of detrended fluctuation analysis (DFA), entropy rate, and approximate entropy to natural activity data and (b) our narrow focus on stepping activity.

Kinematic Evidence For Superfast Locomotory Muscle In Two Species Of Teneriffiid Mites, Grace C. Wu, Jonathan C. Wright, Dwight L. Whitaker, Anna N. Ahn

All HMC Faculty Publications and Research

Locomotory muscles typically operate over a narrow range of contraction frequencies, characterized by the predominant fiber types and functional roles. The highest documented frequencies in the synchronous sound-producing muscles of insects (550 Hz) and toadfish (200 Hz) far exceed the contraction frequencies observed in weight-bearing locomotory muscles, which have maximum documented frequencies below 15-30 Hz. Laws of scaling, however, predict that smaller arthropods may employ stride frequencies exceeding this range. In this study we measured running speed and stride frequency in two undescribed species of teneriffiid mites from the coastal sage scrub of southern California. Relative speeds of both species …

Differences In Muscle Activation In The Lower Extremities While Performing Traditional Squats And Non-Traditional Squats, Christopher M. Scotten

Boise State University Theses and Dissertations

Purpose: To determine if muscle activation in the lower back and lower extremities differ when performing traditional squats compared to non-traditional (forward center of pressure on foot) squats. The erector spinae, hamstrings, quadriceps, adductor longus, gastrocnemius, and gluteus maximus muscles were monitored for differences in this study. There are several variations of the back squat and each variation may possibly target muscles differently. Determining if non-traditional squats leads to larger erector spinae muscle activation, which in turn may lead to more lower back fatigue and possible lower back injury is a major aim of this study. Participants: Thirteen healthy males …

Abnormal Joint Powers Before And After The Onset Of Claudication Symptoms, Panagiotis Koutakis, Jason Johanning, Sara A. Myers, Nikolaos Stergiou, G. Matthew Longo, Iraklis Pipinos

Journal Articles

Objective: Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers.

Methods: Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated …

Relationships Between Muscle Contributions To Walking Subtasks And Functional Walking Status In Persons With Post-Stroke Hemiparesis, Allison Kinney, Carrie L. Peterson, Steven A. Kautz, Richard R. Neptune

Mechanical and Aerospace Engineering Faculty Publications

Walking speed is commonly used to predict stroke severity and assess functional walking status (i.e., household, limited community and community walking status) post-stroke. The underlying mechanisms that limit walking speed (and functional walking status by extension) need to be understood to improve post-stroke rehabilitation. Previous experimental studies have shown correlations between paretic plantarflexor output during the pre-swing phase and walking speed and suggest that the paretic hip flexors can compensate in some hemiparetic subjects. Modeling and simulation studies of healthy walking have shown that the ankle plantarflexors, soleus (SOL) and gastrocnemius (GAS), and uniarticular hip flexors (IL) are essential contributors …

Pre-Swing Deficits In Forward Propulsion, Swing Initiation And Power Generation By Individual Muscles In Hemiparetic Walking, Carrie L. Peterson, Allison Kinney, Steven A. Kautz, Richard R. Neptune

Mechanical and Aerospace Engineering Faculty Publications

Clinical studies of hemiparetic walking have shown pre-swing abnormalities in the paretic leg suggesting that paretic muscle contributions to important biomechanical walking subtasks are different than those of non-disabled individuals. Three-dimensional forward dynamics simulations of two representative hemiparetic subjects with different levels of walking function classified by self-selected walking speed (i.e., limited community=0.4–0.8 m/s and community walkers=>0.8 m/s) and a speed-matched control were generated to quantify individual muscle contributions to forward propulsion, swing initiation and power generation during the pre-swing phase (i.e., double support phase proceeding toe-off). Simulation analyses identified decreased paretic soleus and gastrocnemius contributions to forward propulsion …

Hip Power Asymmetry In Older Adult Fallers And Non-Fallers, Lauren Grace Mcdonald

Boise State University Theses and Dissertations

The purpose of this study was to determine if a difference exists in hip power asymmetry between community-dwelling older adult fallers and non-fallers. Hypothesis: fallers would be more asymmetrical than non-fallers. Participants: 21 non-fallers (10 females, 11 males) and 18 fallers (14 females, 4 males) over the age of 65 (76.5 ± 6.9yrs). Method: Isokinetic peak torque during flexion, extension, abduction, and adduction at four velocities was recorded as measures of leg power. Asymmetry equaled the percent of power difference between each leg. Data analysis: Differences in age, physical activity, height, weight, and BMI were assessed …