Biomechanics Commons^™

Head Stabilization And Cortical Activation In Contact Sport Athletes During Walking Under Different Visual Task Constraints, Sam Zeff

Doctoral Dissertations

Contact sport participation exposes athletes to repetitive sub-concussive head impacts, which have been shown to elicit cortical neurophysiologic, cognitive, and motor performance alterations that have the potential to disrupt visual perception. Despite the growing concern regarding sub-concussive impacts, our understanding of their implications on motor performance and risk for further injury is limited. A stable head provides a consistent perceptual platform for the visual and vestibular sensory systems, but the effects of contact sport participation on head stability and visual perception remain poorly understood. The goal of this dissertation was to understand whether contact sport participation modifies athletes’ ability to …

Age-Related Changes In Corticospinal Drive During Locomotor Adaptation, Sumire D. Sato

Doctoral Dissertations

During activities of daily living, locomotor patterns must be continuously adapted according to changes in our body (e.g., bodily injuries, fatigue) and to the changing environment (e.g., walking surface). Plasticity of spinal networks and supraspinal centers, including the cerebellum and cerebral cortex, have been shown to play important roles in human locomotor adaptation. However, the neural control of locomotion and the ability to adapt locomotor patterns are altered in older adults, which may limit activities of daily living and increase fall-related injuries in the elderly population. My dissertation project is focused on understanding the role of corticospinal drive during split-belt …

The Effects Of Maturation On Acl Loading, Muscle Coordination, And Metabolic Cost In Adolescent Female Soccer Players, Lauren E. Schroeder

Doctoral Dissertations

Anterior cruciate ligament (ACL) injuries remain a significant, season-ending injury in youth soccer, with young female athletes exhibiting higher incidence rates compared to young male athletes. ACL injury rates increase with older ages, with female soccer players 15 years or older being at an almost twofold increased rate of injury compared to young female soccer players. Several biomechanical and neuromuscular changes occur during the maturation process, becoming more prevalent in young females, that can place them at an increased risk for ACL injury. These biomechanical and neuromuscular changes can affect how efficient young females are when completing high-risk, dynamic tasks …

Musculoskeletal Modeling Analysis Of Knee Joint Loading During Uphill And Downhill Waling In Patients With Total Knee Replacement, Tanner A. Thorsen

Doctoral Dissertations

The purposes of these studies were to determine differences in total (TCF), medial (MCF) and lateral (LCF) tibiofemoral compartment compressive forces and related muscle forces between limbs (replaced, non-replaced, and control), and different slopes during uphill [0° (level), 5°, 10°], and downhill [0° (level), 5° 10°] using statistical parametric mapping (SPM). Static optimization was used to determine muscle and compressive forces for 9 patients with total knee arthroplasty (TKA) and 9 control participants during walking trials. Total , loading-response, and push-off TCF impulse were calculated. A 3×3 [Limb (replaced, non-replaced, control] × Slope (0°, 10°, 15°)] SPM[F] repeated measures ANOVA …

An Emg Optimization Model Of The Kinetic Demands On The Lower Back During Asymmetrical Gait And Load Carriage, Jacob J. Banks

Doctoral Dissertations

Gait asymmetries are associated with a high incidence of lower back pain (LBP). Although there are several causes of gait asymmetry (i.e. amputation, injury, or deformities), lower back kinetic demands have not been quantified and suitably compared due to experimental limitations in these clinical populations. Further, the impact of gait asymmetry on lower back demands during carrying tasks has not been established. This dissertation addressed these issues by artificially and safely inducing gait asymmetry in healthy able-bodied participants during walking and carrying tasks. LBP risk was assessed by L5/S1 vertebral joint force levels estimated with an OpenSim musculoskeletal model of …

Efficacy Of A Cycling Intervention With Pedal Reaction Force Augmented Feedback On Reducing Inter-Limb Asymmetries In Patients With Unilateral Total Knee Arthroplasty, Erik T. Hummer

Doctoral Dissertations

Fifteen patients with unilateral total knee arthroplasty (TKA) performed cycling at two workates (80 W and 100 W) and two walking conditions (preferred and fast speeds). Ten of these patients of TKA also participated in a short-term cycling intervention paired with visual augmented feedback of vertical pedal reaction forces for six sessions over two-three weeks. These ten patients of TKA participated in a 2^nd post-training testing session. Study One compared the knee joint biomechanics for all fifteen participants during stationary cycling to ascertain if any biomechanical asymmetries may be present. The replaced limbs displayed significantly lower peak knee extension …

Lower Extremity Muscle Contributions To Acl Loading In Healthy And Acl-Reconstructed Females, Shelby Peel

Doctoral Dissertations

Females are 16 times greater to sustain a second ACL injury compared to their healthy female counterparts. Many of these females return to play their respective sport after an ACL-reconstruction (ACLR). However, little is known about the influence fatigue in sport has on lower extremity mechanics of ACLR females. The purpose of this study was to investigate the influence muscular fatigue may have on lower extremity mechanics in healthy and ACLR females. It was hypothesized that 1) healthy control and ACLR females would demonstrate different hip, knee, and ankle mechanics, regardless of fatigue, 2) fatigue would influence hip, knee, and …

Metabolic Cost Of Asymmetrical Walking: Preferred Step Time Asymmetry Optimizes Metabolic Cost Of Walking, Jan Stenum

Doctoral Dissertations

Hemiparetic and amputee walking often has asymmetrical step lengths and step times, and it is metabolically costlier than symmetrical able-bodied walking. Consequently, asymmetry has been suggested to account for the greater energy expenditure, but the metabolic cost of asymmetrical walking is poorly understood. Conversely, even though symmetry is metabolically optimal in able-bodied walking, it is also possible that asymmetrical gait parameters may be selected if they are optimal under imposed constraints. First, to understand the metabolic cost of asymmetry, we performed experiment 1 in which we recruited 10 able-bodied subjects to walk with a range of different combinations of asymmetrical …

The Roles Of Morphology And Posture On Gait Mechanics, Russell T. Johnson

Doctoral Dissertations

Humans walk with an upright posture, extended limbs during stance, and a double-peaked vertical ground reaction force. Our closest living relatives, chimpanzees, sometimes walk bipedally but do so with a flexed, abducted hind limb. Previous researchers have studied humans walking with a crouched, chimpanzee-like gait pattern to try to infer how extinct human ancestors walked. However, it is not clear if the way humans perform this crouched posture gait would be similar to the way a species that is adapted to walk with a crouched posture would walk. The purpose of this dissertation was to investigate the impact of morphology …

Walking For Object Transport: An Examination Of The Coordinative Adaptations To Locomotor, Perceptual, And Manual Task Constraints, Avelino Amado

Doctoral Dissertations

The goal of this dissertation was to understand how the intrinsic dynamics of gait adapt to support the performance of an ecologically relevant object transport task. A common object transport task is walking with a cup of water. Because the water can move relatively independent of the cup, the cup and water system is classified as a complex object. To model this task participants carried a cup with a wooden lid placed on top. On the lid there was a circular region with the same circumference as the cup and a ball. The object of the task was to keep …

Metabolic Cost And Stability Of Locomotion In People With Lower Limb Amputation, Ryan Wedge

Doctoral Dissertations

It is generally accepted that metabolic energy expenditure and gait stability are key factors that influence the selection of able-bodied locomotor patterns. It is unclear how energy expenditure and gait stability are prioritized during walking in people with lower limb amputation. People with lower limb amputation generally have greater metabolic energy expenditure during walking and increased incidence of falls. People with unilateral lower limb amputation spend more time on the intact limb compared with the prosthetic limb, while able-bodied individuals generally walk with symmetrical timing between limbs. Restoring symmetry is often a goal of rehabilitation and assistive devices, yet the …

Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park

Doctoral Dissertations

Learning many daily life motor skills is critical for survival and the quality of living in humans. As children, we develop walking and running patterns to move the body from point A to B without falling, and we learn to grasp a wide variety of objects during activities of daily living. Motor skills can be properly performed by appropriate muscle activations which are controlled by the central nervous system. How does the central nervous system develop and fine-tune its control strategy to learn a new motor skill? The aim of this dissertation was to better understand how human participants alter …

Physical Activity And Age-Related Mechanical Risk Factors For Knee Osteoarthritis, Jocelyn F. Hafer

Doctoral Dissertations

Knee osteoarthritis is an age-related disease which will affect nearly 50% of individuals in their lifetime. Because there are currently no treatments to substantially slow the progression of this disease, it is important to identify mechanisms to reduce the risk of osteoarthritis initiation. Osteoarthritis is a disease which is at least partially mediated by mechanical factors which may result from age-related changes in gait. The extent to which habitual physical activity can modify the impact of age on gait, knee mechanics, and thus cartilage loading is unknown. The aim of this dissertation was to examine the effects of age and …

Quantifying Gait Adaptability: Fractality, Complexity, And Stability During Asymmetric Walking, Scott W. Ducharme

Doctoral Dissertations

Successful walking necessitates modifying locomotor patterns when encountering organism, task, or environmental constraints. The structure of stride-to-stride variance (fractal dynamics) may represent the adaptive capacity of the locomotor system. To date, however, fractal dynamics have been assessed during unperturbed walking. Quantifying gait adaptability requires tasks that compel locomotor patterns to adapt. The purpose of this dissertation was to determine the potential relationship between fractal dynamics and gait adaptability. The studies presented herein represent a necessary endeavor to incorporate both an analysis of gait fractal dynamics and a task requiring adaptation of locomotor patterns. The adaptation task involved walking asymmetrically on …

Burrowing And Walking Mechanisms Of North American Moles, Yi-Fen Lin

Doctoral Dissertations

Moles (Family Talpidae) are a classic example of extreme specialization, in their case highly derived forelimb morphologies associated with burrowing. Despite many observations of mole burrows and behaviors gathered in the field, we know very little about how and how well moles use their forelimbs to dig tunnels and to walk within the built tunnels to collect and transport food. The first chapter investigates the effect of soil compactness on two sympatric mole species under controlled laboratory conditions. My results demonstrate that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter …

The Consequences Of Speed: Studies Of Cavitation During The Mantis Shrimp Strike And The Control Of Rapid Deceleration During Toad Landing, Suzanne M. Cox

Doctoral Dissertations

There are consequences of moving quickly in this world. Here we investigate how two very different species, mantis shrimp (Odontodactylus scyllarus) and cane toads (Bufo marinus), negotiate forces that result from moving rapidly in different environments. To study the mechanical principles and fluid dynamics of ultrafast power-amplified systems, we built Ninjabot, a physical model of the extremely fast mantis shrimp. While mantis shrimp produce damaging cavitation upon impact with their prey, they do not cavitate during the forward portion of their strike despite extreme speeds. In order to study cavitation onset in non-linear flows common during …

Static Frontal Plane Tibiofemoral Alignments And Their Effects On Knee Biomechanics During Level Walking And Stair Ascent Tasks, Hunter Jared Bennett

Doctoral Dissertations

Knee osteoarthritis is a degenerative joint disease that can onset due to abnormal knee adduction moments (KAMs), which are related to frontal plane knee joint alignment. Gait modifications including toe-in (TI) and wider step widths have been proposed as individual intervention strategies, but have not been previously combined, to reduce abnormal frontal plane loading in healthy and osteoarthritic populations. Study One investigated clinical based measurements to predict radiographic frontal plane knee joint alignment, measured as the mechanical axis angle (MA). Study Two compared three different hip joint center estimation methods on MA predictions using three-dimensional motion capture. Study Three and …

The Influence Of Musculoskeletal Geometry On The Metabolic Cost Of Pedaling, Lex Gidley

Doctoral Dissertations

The human musculoskeletal system consists of several muscles crossing each joint. In the human lower limb, most major muscles cross either one or two joints; labeled as uniarticular or biarticular muscles, respectively. The major biarticular muscles of the leg are the rectus femoris, hamstrings, and gastrocnemius. Several suggestions have been proposed as to how biarticular muscles may reduce the metabolic cost of human movement. Using experimental protocols, it is difficult to address the energetic effects of biarticular muscles, as individual muscle contributions to human movement cannot be measured and there is no way to determine what the effect might be …

Plantar Pressure, Cutaneous Sensation And Stochastic Resonance: An Examination Of Factors Influencing The Control And Perception Of Posture, Michael A. Busa

Doctoral Dissertations

The goal of this dissertation was to understand how people control posture in the context of sensory loss. To do so we explored three potential influences on the detection of external information and how they relate to the control of posture and perception of body orientation: 1) does changing posture alter the forces under the foot, and do these changes impact the ability to detect external vibrations? 2) Does decreasing the temperature of the foot influence the ability to detect external vibrations, the perception of body orientation, and the control of posture? And 3) does stochastic resonance (SR) improve the …

Effects Of Foot Type On Multi-Segment Foot Motion In High- And Low-Arched Female Recreational Athletes, Douglas W. Powell

Doctoral Dissertations

Introduction: Mal-alignment and dysfunction of the foot have been shown to result in an increased rate of injury and unique injury patterns. Aberrant foot function has been shown to contribute to repetitive stress and acute injuries. High-arched athletes have been shown to experience a greater rate of bony injury to the lateral aspect of the lower extremity while low-arched athletes experience greater rates of soft-tissue injury to the medial aspect of the lower extremity. Though foot type has been linked to these injury patterns, the mechanism by which these injury patterns occur remains unknown. Multi-segment foot models have been developed …

A Description Of The Movement Of The Canine Pelvic Limb In Three Dimensions Using An Inverse Dynamics Method, And A Comparison Of Two Techniques To Surgically Repair A Cranial Cruciate Ligament Deficient Stifle, Jason Headrick

Doctoral Dissertations

The purposes of the dissertation were: 1) to describe three-dimensional (3D) motion of the canine pelvic limb using an inverse dynamics method, and 2) to compare these motion patterns between normal, healthy dogs and those that have had their stifles stabilized by one of two surgical methods approximately five years earlier.

Twenty-five dogs were allocated to three groups; healthy control dogs, dogs that had received the tibial plateau leveling osteotomy (TPLO), and dogs that had received the lateral fabellar suture (LFS) stabilization technique. Both surgical techniques were performed approximately five years prior on stifles with surgically induced cranial cruciate ligament …

Effects Of Increased Step Width On Knee Joint Biomechanics In Healthy And Knee Osteoarthritis Older Adults During Stair Descent, Maxime Robert Paquette

Doctoral Dissertations

Stair negotiation is one of the most challenging tasks for older adults especially for those suffering from knee osteoarthritis (OA). To date, no studies have investigated the effects of increased step width (SW) on knee joint biomechanics. The purpose of Study One was to investigate the effects of increased SW on peak internal knee abduction moment and other lower extremity variables during stair descent in healthy older adults. The purpose of Study Two was to investigate the effects of increased SW on peak internal knee abduction moment, knee pain and other lower extremity variables during stair descent in medial compartment …

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: …