Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Physical activity (5)
- Biomechanics (4)
- Kinematics (4)
- Control (3)
- Coordination (3)
-
- Locomotion (3)
- Metabolic cost (3)
- Muscle (3)
- Accelerometer (2)
- Aging (2)
- Children (2)
- Eccentric exercise (2)
- Gait (2)
- Kinetics (2)
- Learning (2)
- Sleep (2)
- Variability (2)
- Walking (2)
- 31P-MRS (1)
- ATP cost (1)
- Abiotic (1)
- Academic performance (1)
- Acidosis (1)
- ActiGraph Activity Monitors (1)
- Activity Tracker (1)
- Activity type classification (1)
- Adaptation (1)
- Aging gait (1)
- Aging muscle function (1)
- Amputee (1)
Articles 1 - 30 of 32
Full-Text Articles in Life Sciences
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 …
Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii
Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii
Doctoral Dissertations
Muscle size does not fully explain variations in muscle strength. Fat content has been implicated in muscle weakness, though this relationship remains unclear. The relationship between fat and strength may vary between scales (e.g., cellular, organ, and organism). The goal of this dissertation was to clarify the role of fat in the structure and function of muscle using in vitro and in vivo techniques across multiple scales in adults 21-45 years old. Study 1 tested the agreement of intramyocellular lipid (IMCL) content between oil red o (ORO) and magnetic resonance spectroscopy (MRS) techniques. These measures of IMCL were also compared …
Controlling Myosin’S Function Via Interactions Between The Substrate And The Active Site, Mike K. Woodward
Controlling Myosin’S Function Via Interactions Between The Substrate And The Active Site, Mike K. Woodward
Doctoral Dissertations
Molecular motors, such as myosin, have evolved to transduce chemical energy from ATP into mechanical work to drive essential cellular processes, from muscle contraction to vesicular transport. Dysfunction in these motors is a root cause of many pathologies necessitating the application of intrinsic control over molecular motor function. We hypothesized that altering the myosin’s energy substrate via minor positional changes to the triphosphate portion of the molecule will allow us to control the protein and affect its in vitro function. We utilized positional isomers of a synthetic non-nucleoside triphosphate, azobenzene triphosphate, and assessed whether myosin’s force- and motion-generating capacity could …
Age-Related Changes In Corticospinal Drive During Locomotor Adaptation, Sumire D. Sato
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 …
An Emg Optimization Model Of The Kinetic Demands On The Lower Back During Asymmetrical Gait And Load Carriage, Jacob J. Banks
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 …
Design And Biomechanical Evaluation Of A Clutch-Based Energy Storage And Release Assistive Knee Brace, Ericber Jimenez Francisco
Design And Biomechanical Evaluation Of A Clutch-Based Energy Storage And Release Assistive Knee Brace, Ericber Jimenez Francisco
Doctoral Dissertations
Knee osteoarthritis (OA) is a serious degenerative disease affecting over 240 million people around the world. The most disabling symptoms are joint pain, joint stiffness, and reduction in joint functionality. Medial compartment knee OA is the most common case of unicompartmental knee OA, and pain and progression have been associated with tibiofemoral alignment in early to moderate knee OA patients, mainly due to its association with knee loading as measured by knee adduction moment (KAM) and tibiofemoral contact forces (KCF). Valgization knee braces have been developed to correct the malalignment at the tibiofemoral joint, but they have no direct effect …
Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald
Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald
Doctoral Dissertations
Muscle fatigue is defined as the reduced capacity to produce torque or power in response to contractile activity. Previous work has observed greater fatigue in older than young adults in response to high-velocity contractions, but similar fatigue with age in response to moderate-velocity contractions. The mechanisms for these age-related differences is not clear. One potential explanation is a greater accumulation of putative agents of fatigue (e.g., Pi, H2PO4-, and H+) in older than young muscle during high- but not moderate-velocity contractions. Older muscle may accumulate these metabolites to greater extent because of deficits …
Metabolic Cost Of Asymmetrical Walking: Preferred Step Time Asymmetry Optimizes Metabolic Cost Of Walking, Jan Stenum
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 …
Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett
Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett
Doctoral Dissertations
Skeletal muscle oxidative capacity plays a critical role in human health and disease. Although current models of oxidative phosphorylation sufficiently describe skeletal muscle energetics during moderate-intensity contractions, much is still unknown about the mechanisms that control and limit oxidative phosphorylation during high-intensity contractions. In particular, the oxygen cost of force generation is augmented during exercise at workloads above the lactate threshold. Presently, it is unclear whether this augmentation in muscle oxygen consumption is driven by increased rates of oxidative ATP synthesis (ATPOX) or by decreases in the efficiency of ATPOX due to mitochondrial uncoupling. To address this …
The Roles Of Morphology And Posture On Gait Mechanics, Russell T. Johnson
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 …
Sleep-Dependent Consolidation Of Locomotor Sequence Learning And Locomotor Adaptation, Gabriela Borin Castillo
Sleep-Dependent Consolidation Of Locomotor Sequence Learning And Locomotor Adaptation, Gabriela Borin Castillo
Doctoral Dissertations
Walking is a complex task that requires precise coordination of many muscles and joints. The nervous system must continually learn how to control gait patterns as changes occur to the body (e.g., injury and fatigue) or environment (e.g., slippery floor). Motor learning refers to processes that improve the spatial and/or temporal accuracy of a movement through motor practice. Although additional hours of practice can improve motor skill performance (online learning), time without additional practice (offline learning) can further enhance motor learning. Consolidation refers to the process by which motor (procedural) memory becomes more robust and stable after the end of …
Walking For Object Transport: An Examination Of The Coordinative Adaptations To Locomotor, Perceptual, And Manual Task Constraints, Avelino Amado
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 …
Feasibility, Acceptability, And Preliminary Efficacy Of An Academically-Integrated Physical Activity Program On Classroom Behavior In Preschoolers, Sarah Burkart
Doctoral Dissertations
Maladaptive classroom behaviors (i.e., hyperactivity, inattention) are common in preschoolers, yet elevated levels may lead to future academic difficulties or attention-deficit/hyperactivity disorder (ADHD). Physical activity (PA) may be one way to alleviate these maladaptive behaviors within the classroom, yet preschoolers are not meeting PA guidelines. Implementing academically-integrated PA may serve a two-fold benefit of enhancing PA and classroom behavior. However, process evaluation data describing academically-integrated PA interventions are sparse. Therefore, the purpose of this study was to examine the feasibility, acceptability, and preliminary efficacy of a 12-week PA intervention integrated into early learning standards on classroom behavior in preschoolers. Two …
Metabolic Cost And Stability Of Locomotion In People With Lower Limb Amputation, Ryan Wedge
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 …
Feasibility And Efficacy Of A Recess-Based Combined Fitness Intervention On Cognition And Academic Performance In Elementary School Children, Christine St Laurent
Feasibility And Efficacy Of A Recess-Based Combined Fitness Intervention On Cognition And Academic Performance In Elementary School Children, Christine St Laurent
Doctoral Dissertations
Youth physical activity and fitness have been reported to influence cognition and academic related outcomes. Despite the potential benefits of muscular fitness, few intervention studies have examined the impact of an intervention that has incorporated both cardiorespiratory and muscular fitness training on cognition and academic performance in children. Previous studies have mainly been implemented either during the school day or immediately after-school. Although recess may be an ideal time to promote physical activity because it does not compete with other academic demands, it has been an understudied setting. Therefore, the purpose of this dissertation project was to examine the feasibility, …
Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park
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 …
Cardiovascular Disease Risk And Menopause: Effects Of Cardiorespiratory Fitness, Exercise, And Follicle Stimulating Hormone, Corinna Serviente
Cardiovascular Disease Risk And Menopause: Effects Of Cardiorespiratory Fitness, Exercise, And Follicle Stimulating Hormone, Corinna Serviente
Doctoral Dissertations
Menopause is associated with adverse changes in cardiovascular disease risk factors. A reduction in estrogens is most commonly associated with changing cardiovascular disease risk; however, recent observations suggest that the increase in follicle stimulating hormone that accompanies menopause may also influence risk, potentially through its influence on lipid levels. The changes in cardiovascular disease risk factors may adversely affect endothelial cell function, a pre-clinical marker for cardiovascular disease. Whether cardiorespiratory fitness is protective of endothelial health in this population, thereby mitigating the changes in risk that accompany menopause, is unclear. This dissertation evaluated differences in endothelial health and endothelial responses …
Feasibiity And Efficacy Of A Movement-Training Program On Physical Fitness, Fundamental Movement Skills, And Physical Activity In Third And Fourth Grade Students, Brittany Masteller
Feasibiity And Efficacy Of A Movement-Training Program On Physical Fitness, Fundamental Movement Skills, And Physical Activity In Third And Fourth Grade Students, Brittany Masteller
Doctoral Dissertations
Recent initiatives have focused on exploring the relationship between fitness, fundamental movement skills, psychosocial mediators, and physical activity in children to help design better interventions to improve these behaviors. FUNdamental Integrative Training (FIT) is an approach to physical education that uses age-appropriate exercises to improve physical fitness in youth, with the longer-term goal to physically prepare children for an active lifestyle beyond childhood. We evaluated the feasibility and efficacy of a 12-week, FIT program on physical fitness, fundamental movement skills, psychosocial mediators (self-efficacy, enjoyment and social support), and physical activity, among third and fourth grade students. Seven classrooms in one …
Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear
Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear
Doctoral Dissertations
Muscle contracts after calcium (Ca++) is released into the muscle cell, resulting from a cascade of events which result in myosin, the molecular motor of muscle, to produce force and motion. Myosin cyclically binds to a regulated thin filament, using the chemical energy of ATP to produce force and motion. Perturbations in muscle, such as a build-up of metabolic by-products or point mutations in key contractile proteins, can inhibit these functions in both skeletal and cardiac muscle either acutely or chronically. Despite the many years we have studied skeletal and cardiac muscle, we still do not have a clear picture …
Physical Activity And Age-Related Mechanical Risk Factors For Knee Osteoarthritis, Jocelyn F. Hafer
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 …
A Comprehensive Validation Of Activity Trackers For Estimating Physical Activity And Sedentary Behavior In Free-Living Settings, Albert R. Mendoza
A Comprehensive Validation Of Activity Trackers For Estimating Physical Activity And Sedentary Behavior In Free-Living Settings, Albert R. Mendoza
Doctoral Dissertations
The aim of study one of this dissertation was to compare consumer activity trackers (ATs) with the research-grade ActiGraph™ GT3X-BT accelerometer (AG) in estimating energy expenditure (EE) and steps during orbital shaking at different frequencies. To address this aim, we utilized an electronic orbital shaking protocol (twenty-four, 3-minute trials; 2-hour trials). For all comparisons, the AG served as the reference measure. In the 3-min protocol, we showed that on average, the NL-1000 pedometer (NL) produced the lowest error (-9 steps/3-min) at 0.9 Hz (corresponding to moderate intensity). The magnitude of the error for the NL was 14 steps/3-min at a …
Quantifying Gait Adaptability: Fractality, Complexity, And Stability During Asymmetric Walking, Scott W. Ducharme
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
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 …
Interfacing Continuous Measurement Of Glucose And Physical Activity To Predict Glycemic Control In Individuals With Type 2 Diabetes, Jennifer Blankenship
Interfacing Continuous Measurement Of Glucose And Physical Activity To Predict Glycemic Control In Individuals With Type 2 Diabetes, Jennifer Blankenship
Doctoral Dissertations
Physical activity is a cornerstone in the management of hyperglycemia and risk of cardiovascular disease in type 2 diabetes (T2D). However, the dose response relationship between physical activity and glucose regulation is not well defined. The overall goal of this dissertation was to assess the magnitude and timing of changes of daily glucose concentrations in response to continuous and intermittent light physical activity in T2D. Through utilizing continuous glucose monitors (CGM) and physical activity monitoring concurrently, we were able to assess the glycemic impact of physical activity and sedentary behavior in the free-living environment. Study 1 aimed to examine the …
The Consequences Of Speed: Studies Of Cavitation During The Mantis Shrimp Strike And The Control Of Rapid Deceleration During Toad Landing, Suzanne M. Cox
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 …
Feasibility Of A Combined Physical Activity And Sleep Education Intervention For Girls Living In A Low Socioeconomic Status Urban Community, Cory J. Greever
Feasibility Of A Combined Physical Activity And Sleep Education Intervention For Girls Living In A Low Socioeconomic Status Urban Community, Cory J. Greever
Doctoral Dissertations
Declining sleep duration and poor sleep quality is a public health epidemic disproportionately effecting elementary age girls living in low socioeconomic status urban communities. The Girls Dancing and Sleeping for Health (Girls DASH) program was designed to test the feasibility, acceptability, and efficacy of a combined physical activity and sleep education program in this population. In combination with baseline data from a previously conducted intervention in elementary age urban girls living in a low SES community in Springfield, MA, results from a cross-sectional analysis indicated that greater screen time was positively associated with parental reports of child’s sleep quality. Additionally, …
The Influence Of Musculoskeletal Geometry On The Metabolic Cost Of Pedaling, Lex Gidley
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 …
Molecular Mechanisms Underlying The Contralateral Repeated Bout Effect (Crbe) In Human Skeletal Muscle, Ling Xin
Doctoral Dissertations
Eccentric (muscle lengthening) exercise induces temporary muscle damage that can lead to long-term muscle adaptation, a process known as the repeated bout effect where subsequent exercise results in less damage. The existence of a contralateral repeated bout effect (CRBE) has been controversial. The primary goals of this study were to: 1) validate the existence of the CRBE; and 2) define the underlying molecular mechanisms. Thirty-six young men performed 100 maximal eccentric actions of the knee extensors using one leg (bout 1) and repeated the exercise with the contralateral leg five weeks later (bout 2). Vastus lateralis muscle biopsies were …
Impact Of A Preschool Workplace Intervention On Classroom Teachers’ Physical Activity Levels And Quality Of Life, Ogechi O. Nwaokelemeh
Impact Of A Preschool Workplace Intervention On Classroom Teachers’ Physical Activity Levels And Quality Of Life, Ogechi O. Nwaokelemeh
Doctoral Dissertations
PURPOSE: To examine the feasibility and efficacy of a three-month, cluster-randomized workplace PA intervention on PA levels and wellbeing measures in preschool classroom teachers. METHODS: Ten preschool centers were randomized into two groups; short-bouts of structured PA (SBS-PA, n=5) or traditional unstructured PA (TRAD-PA, n=5). The SBS-PA intervention consisted of 10-minute structured, teacher-led PA routines implemented within the classroom setting, followed by 20 minutes of unstructured playtime. The TRAD-PA intervention consisted of supervised 30-minute of unstructured free playtime. Both interventions were implemented during the morning and afternoon designated gross-motor playtime for 30 min/session, five days/week for three months. Participants’ …
The Role Of The Extracellular Matrix In Mediating Muscle Soreness, Karen L. Riska
The Role Of The Extracellular Matrix In Mediating Muscle Soreness, Karen L. Riska
Doctoral Dissertations
The goal of this dissertation was to examine the role of the extracellular matrix (ECM) in muscle soreness. Study 1 examined how the disruption of the ECM from a minor surgery (e.g. muscle biopsy) affected muscle soreness. Study 1 showed that soreness levels increased at 24 h post-biopsy compared to baseline and resolved within 96 h. However, the level of muscle soreness at 24 h post-biopsy (20 mm) was lower than that reported for performing a strenuous and naïve exercise (40–80 mm). These results will help review boards at institutions where muscle biopsies are performed understand how a muscle biopsy …