Biomechanics Commons^™

Football Helmet Fitment And Its Effect On Helmet Performance, Ron Jadischke

Wayne State University Theses

A method and system to objectively quantify helmet fitment was designed and developed. It measures the pressure between the energy-absorbing material in the helmet and the athlete's head. This system is also capable of measuring surface pressure during impact events. A volunteer-based field study was conducted to quantify how helmets were fitting athletes in a real-life setting. The helmets fit athletes in varying degrees of tightness and evenness. Most athletes (59%) had the highest pressures in the frontal area and 29% had the highest pressure in the occipital area. A large-sized helmet on the Hybrid III headform represented how most …

Contact Pressure Distribution Of Osteochondral Defects Of The Knee: Effects Of Non-Vertical Walls, Scott Ensminger

Wayne State University Theses

Purpose: To examine the relationship between well-shouldered osteochondral defects and

defects of different geometries by studying their effects on rim stress concentration and

load redistribution in the human knee.

Methods: Ten fresh-frozen cadaveric knees were mounted at 30° of flexion in a materials

testing machine. Digital electronic pressure sensors were placed in the medial and lateral

compartments of the knee. Dynamic pressure readings were recorded throughout the

loading and holding phases as each knee was loaded to 700N and held for 5 seconds.

Artificial defects were created in each knee to simulate well-shouldered defects and

beveled-defects. Loading was repeated for …

Reliability Of Semiautomated Computational Methods For Estimating Tibiofemoral Contact Stress In The Multicenter Osteoarthritis Study, Donald D. Anderson, Neil A. Segal, Andrew M. Kern, Michael C. Nevitt, James C. Torner, John A. Lynch

Journal Articles

Recent findings suggest that contact stress is a potent predictor of subsequent symptomatic osteoarthritis development in the knee. However, much larger numbers of knees (likely on the order of hundreds, if not thousands) need to be reliably analyzed to achieve the statistical power necessary to clarify this relationship. This study assessed the reliability of new semiautomated computational methods for estimating contact stress in knees from large population-based cohorts. Ten knees of subjects from the Multicenter Osteoarthritis Study were included. Bone surfaces were manually segmented from sequential 1.0 Tesla magnetic resonance imaging slices by three individuals on two nonconsecutive days. Four …

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 …

An Unstable Shoe With A Rocker Bottom Redistributes External Work, Shane R. Wurdeman, Jenna M. Yentes, Neil B. Huben, Nikolaos Stergiou

Journal Articles

The purpose of this study was to examine the external work performed by individuals wearing a rocker bottom shoe compared to a standard shoe. It was hypothesized that individuals wearing a rocker bottom shoe would have changes in the amount of work over the course of contact with the ground. External work on the body’s centre of mass (BCOM) was calculated for individuals in both conditions. Comparisons for external work were done for positive and negative work for the entire stance phase as well as the initial double support, single support and terminal double support periods. The results revealed that …

Estimates Of Critical Power And Anaerobic Work Capacity From A Single, All-Out Test Of Less Than 3-Min, H C. Bergstrom, T J. Housh, Jorge M. Zuniga, C L. Camic, D A. Traylor, R W. Lewis, R J. Schmidt, G O. Johnson

Journal Articles

The purpose of this study was to determine if Critical Power (CP) and Anaerobic Work Capacity (AWC) could be estimated from a single, all-out test of less than 3-min. Twenty-eight subjects (mean ± SD: age 23.3 ± 3.3 years, body mass 71.6 ± 16 kg) performed an incremental cycle ergometer test to exhaustion to determine peak oxygen consumption rate and heart rate peak. The 3-min all-out test was used to determine the criterion and six estimated values of CP and AWC. The criterion critical power (CP180) and anaerobic work capacity (AWC180) values were determined from the 3-min all-out test and …

Training Dual-Task Walking In Community-Dwelling Adults Within 1 Year Of Stroke: A Protocol For A Single-Blind Randomized Controlled Trial, Prudence Plummer-D'Amato, Anastasia Kyvelidou, Dagmar Sternad, Bijan Najafi, Raymond M. Villalobos, David Zurakowski

Journal Articles

No abstract provided.

Supervised Resistance Training Results In Changes In Postural Control In Patients With Multiple Sclerosis, Jessie M. Huisinga, Mary Filipi, Nikolaos Stergiou

Journal Articles

Postural disturbances are one of the first reported symptoms in patients with Multiple Sclerosis (MS). The purpose of this study was to investigate the effect of supervised resistance training on postural control in MS patients. Postural control was assessed using amount of sway variability [Root Mean Square (RMS)] and temporal structure of sway variability [Lyapunov Exponent (LyE)] from 15 MS patients. Posture was evaluated before and after completion of three months of resistance training. There were significant differences between MS patients pretraining and healthy controls for both LyE (p = .000) and RMS (p = .002), but no differences between …

The Biomechanics Of Tongue Projection In The Frog _Rana Pipiens_: Dynamics And Temperature Effects, Paula Sandusky

USF Tampa Graduate Theses and Dissertations

Ectotherms such as frogs must either function within environments with temperatures amenable to their physiological needs, or find means to reduce the impact of temperature on their activities. Recent studies on reptile and amphibian feeding have shown convergent use of elastic recoil to drive feeding movements, thereby decoupling temperature's effects on muscle from movement and allowing the animals to feed over broader temperature ranges. Rana pipiens specimens (n=5) were exposed to three ambient temperatures (10°, 15°, and 25° C) at which feeding behavior was imaged at 6000 Hz. The image sequences yielded detailed kinematic and dynamic information for jaw, tongue, …

Endurance Markers Are Related With Local Neuromuscular Response For The Intact But Not For The Acl Reconstructed Leg During High Intensity Running, Kostas Patras, Giorgos Ziogas, Stavros Ristanis, Elias Tsepis, Vasilis Tsiaras, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

AIM: It has been demonstrated that the local neuromuscular response during high intensity exercise has a strong relationship with endurance markers. However, a diminished neuromuscular response has been reported for the operated leg in athletes having undergone anterior cruciate ligament reconstruction (ACLR). The purpose of the present study was to examine the relationships between endurance markers and the EMG response during high intensity running in ACLR athletes. METHODS: Fourteen ACLR soccer players underwent a GXT test to volitional exhaustion and a 10-min bout of high intensity running. During the 10-min bout, EMG data were recorded at the 3rd …

Computational Approaches To Understand Phenotypic Structure And Constitutive Mechanics Relationships Of Single Cells, Scott Wood

All Dissertations

The goal of this work is to better understand the relationship between the structure and function of biological cells by simulating their nonlinear mechanical behavior under static and dynamic loading using image structure-based finite element modeling (FEM). Vascular smooth muscle cells (VSMCs) are chosen for this study due to the strong correlation of the geometric arrangement of their structural components on their mechanical behavior and the implications of that behavior on diseases such as atherosclerosis.
VSMCs are modeled here using a linear elastic material model together with truss elements, which simulate the cytoskeletal fiber network that provides the cells with …

Human Movement Variability, Nonlinear Dynamics, And Pathology: Is There A Connection?, Nikolaos Stergiou, Leslie M. Decker

Journal Articles

Fields studying movement generation, including robotics, psychology, cognitive science, and neuroscience utilize concepts and tools related to the pervasiveness of variability in biological systems. The concept of variability and the measures for nonlinear dynamics used to evaluate this concept open new vistas for research in movement dysfunction of many types. This review describes innovations in the exploration of variability and their potential importance in understanding human movement. Far from being a source of error, evidence supports the presence of an optimal state of variability for healthy and functional movement. This variability has a particular organization and is characterized by a …

Is There A Relationship Between Fatigue Questionnaires And Gait Mechanics In Persons With Multiple Sclerosis?, Jessie M. Huisinga, Mary Filipi, Kendra K. Schmid, Nikolaos Stergiou

Journal Articles

Objective: To evaluate reported fatigue levels and gait deficits in patients with multiple sclerosis (MS) to determine the relationships that may exist between fatigue in patients with MS and alterations in gait mechanics.

Design: Cross-sectional.

Setting: Biomechanics laboratory.

Participants: Subjects with MS (n=32) and age- and sex-matched controls (n=30).

Interventions: None.

Main Outcome Measures: Fatigue Severity Scale (FSS), Modified Fatigue Index Scale (MFIS), and 36-Item Short Form Health Survey (SF-36) to assess fatigue and general health. Biomechanical gait analysis was performed to measure peak joint torques and powers in the sagittal plane at the ankle, knee, and hip. Correlations …

Effectiveness Of Group Kickboxing As A Means To Improve Gait And Balance In Individuals With Ms, Kurt Jackson, Kimberly Edginton Bigelow, Christina Cooper, Harold L. Merriman

Mechanical and Aerospace Engineering Faculty Publications

In recent years, there has been a particular emphasis on identifying and delivering appropriate therapeutic interventions that address the significant balance and gait impairments that affect individuals with multiple sclerosis (MS). Group interventions implemented in community settings have been especially of interest, including tai chi classes. Recently, the authors conducted a preliminary study to examine whether group kick-boxing, which requires more vigorous movements, might be a feasible intervention. Initial findings showed promise and led the authors to pursue a more rigorous follow-up study, with the objective of determining whether a 5-week group kickboxing class improved clinical measures of balance and …

New Insights Into Anterior Cruciate Ligament Deficiency And Reconstruction Through The Assessment Of Knee Kinematic Variability In Terms Of Nonlinear Dynamics, Leslie M. Decker, Constantina O. Moraiti, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Purpose

Injuries to the anterior cruciate ligament (ACL) occur frequently, particularly in young adult athletes, and represent the majority of the lesions of knee ligaments. Recent investigations suggest that the assessment of kinematic variability using measures of nonlinear dynamics can provide with important insights with respect to physiological and pathological states. The purpose of the present article was to critically review and synthesize the literature addressing ACL deficiency and reconstruction from a nonlinear dynamics standpoint.

Methods

A literature search was carried out in the main medical databases for studies published between 1990 and 2010.

Results

Seven studies investigated knee kinematic …

From The W-Method To The Canonical-Dissipative Method For Studying Uni-Manual Rhythmic Behavior, Dobromir Dotov, Till D. Frank

Journal Articles

A novel method for the analysis of repetitive limb behavior oscillation is presented. It is based on a model used to account for self-sustained limit cycles that involve energy pumping compensating for dissipative processes. The experiment involved a uni-manual pendulum swinging task paced at five frequencies. The median frequency corresponded to the resonant one for the chosen pendulum and hand parameters. We applied the model-based analysis to explore the relationship between behavioral observables and model parameters not available from previous methods. Oscillation amplitude and energy, and motor variability were the behavioral observables we focused on while energy pumping, attractor strength, …

Gait Variability Of Patients With Intermittent Claudication Is Similar Before And After The Onset Of Claudication Pain, Sara A. Myers, Iraklis Pipinos, Jason Johanning, Nikolaos Stergiou

Journal Articles

Background

Recent research demonstrated that intermittent claudication patients have increased gait variability prior to the onset of claudication. However, it is unknown if these patients experience additional gait adaptations after the onset of claudication. Thus, we sought to determine how gait variability is affected by claudication in an effort to contribute to improved clinical management.

Methods

Twenty-six intermittent claudication patients and 20 controls walked on a treadmill at self-selected speed; intermittent claudication patients were tested before (pain free) and after (pain) the onset of claudication. Variability of the ankle, knee, and hip joint angles was assessed using the largest Lyapunov …

Knee Braces Can Decrease Tibial Rotation During Pivoting That Occurs In High Demanding Activities, Dimitrios Giotis, Vasilios Tsiaras, Stavros Ristanis, Franceska Zampeli, Grigoris Mitsionis, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Purpose

The purpose of this study was to investigate whether knee braces could effectively decrease tibial rotation during high demanding activities.

Methods

Using an in vivo three-dimensional kinematic analysis, 21 physically active, healthy, male subjects were evaluated. Each subject performed two tasks that were used extensively in the literature because they combine increased rotational and translational loads on the knee, (1) descending from a stair and subsequent pivoting and (2) landing from a platform and subsequent pivoting under three conditions: (A) wearing a prophylactic brace (braced), (B) wearing a patellofemoral brace (sleeved), and (C) unbraced condition.

Results

In the first …

Athletic Training Students' Ability To Identify Scapular Dyskinesis, Priscilla M. Dwelly

Graduate Theses and Dissertations

Scapular dyskinesis refers to abnormal movement patterns of the scapula, which have been associated with injury. Previous investigations have validated the scapular dyskinesis test as a visual assessment method using physicians, physical therapists, and certified athletic trainers. Through educational programs, athletic training students should be taught what scapular dyskinesis is and how to identify it. Therefore, the purpose of this investigation was to (a) evaluate entry-level graduate athletic training students' ability to identify scapular dyskinesis, (b) assess their reliability, and (c) determine if they were able to correctly identify the muscles involved in rehabilitating an individual with scapular dyskinesis. Follow-up …

An Exploratory Biomechanical Analysis Of The Side-To-Side Swing Patterns Of Three Skilled Switch Hitters, Francesca Marie Castellucci

Master's Theses

The ability to successfully switch hit, or hit a baseball from both sides of the plate, requires a great amount of practice and coordination bilaterally. This study used three-dimensional kinematic and kinetic data to examine the swing patterns of skilled switch hitters in baseball. Three male minor league and division I collegiate switch hitters participated. Subjects stood on force plates and hit baseballs off a tee while their swings were recorded with a three-dimensional optical motion capture system. Each subject performed twenty total swings, ten from the right and ten from the left. The swings were digitally analyzed and the …