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1.  Arterial Compliance in Obese Children: Implications for Cardiovascular Health 
Recent work showed that arterial compliance may be unexpectedly elevated in obese children, attributable to accelerated growth and maturation. We hypothesize that children with obesity or type 2 diabetes may reach peak arterial maturation earlier in life and then experience an earlier, and potentially more rapid decline in arterial compliance, leading toward earlier cardiovascular disease development.
PMCID: PMC4169716  PMID: 25062003
arterial compliance; arterial stiffness; vascular health; adolescents; maturation
2.  Skeletal Muscle Hypertrophy after Aerobic Exercise Training 
Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss.
PMCID: PMC4523889  PMID: 24508740
protein metabolism; endurance exercise; sarcopenia; anabolic resistance; ubiquitin proteasome pathway; myostatin; mitochondria
3.  Dynamic Ultrasound Imaging Applications to Quantify Musculoskeletal Function 
Advances in imaging methods have led to new capability to study muscle and tendon motion in vivo. Direct measurements of muscle and tendon kinematics using imaging may lead to improved understanding of musculoskeletal function. This review presents quantitative ultrasound methods for muscle dynamics that can be used to assess in vivo musculoskeletal function when integrated with other conventional biomechanical measurements.
PMCID: PMC4066199  PMID: 24949846
muscle elastography; muscle kinematics; contraction velocity; strain rate; vector Doppler Imaging
4.  Electron Paramagnetic Resonance: A High-Resolution Tool for Muscle Physiology 
Skeletal muscle function can be altered by changes in protein structure and motion. Electron paramagnetic resonance (EPR) paired with site-directed spin labeling has been used to study the relationships between (a) muscle force and myosin structure and (b) muscle relaxation and Ca-ATPase motion and structure.
PMCID: PMC4404760  PMID: 11210444
skeletal muscle; aging; myosin; Ca-ATPase; protein structure; aggregation
5.  The Simplest Motor Skill: Mechanisms and Applications of Reflex Operant Conditioning 
Operant conditioning protocols can gradually change spinal reflexes, which are the simplest behaviors. This article summarizes the evidence supporting two propositions: that these protocols provide excellent models for defining the substrates of learning; and that they can induce and guide plasticity to help restore skills such as locomotion that have been impaired by spinal cord injury or other disorders.
PMCID: PMC4051236  PMID: 24508738
Skill acquisition; H-reflex; spinal cord plasticity; learning; locomotion; spinal cord injury
6.  The Emerging Biomolecular Role of Vitamin D in Skeletal Muscle 
In this review, we summarize current evidence for a direct effect of vitamin D on skeletal muscle. A number of studies identify the receptor for 1,25-dihydroxyvitamin-D3 (vitamin D receptor (VDR)) and the enzyme CYP27B1 (1-α-hydroxylase) in muscle. We hypothesize that vitamin D acts on myocytes via the VDR, and we examine proposed effects on myocyte proliferation, differentiation, growth, and inflammation.
PMCID: PMC4369924  PMID: 24508736
skeletal muscle; vitamin D; vitamin D receptor; aging; 25-hydroxyvitamin D
7.  Exercise Physiology versus Inactivity Physiology: An Essential Concept for Understanding Lipoprotein Lipase Regulation 
Some health-related proteins such as lipoprotein lipase may be regulated by qualitatively different processes over the physical activity continuum, sometimes with very high sensitivity to inactivity. The most powerful process known to regulate lipoprotein lipase protein and activity in muscle capillaries may be initiated by inhibitory signals during physical inactivity, independent of changes in lipoprotein lipase messenger RNA.
PMCID: PMC4312662  PMID: 15604935
dose response; coronary heart disease (CHD); transcription; posttranslational; signaling; sedentary; aging
8.  Exercise, Stress Resistance, and Central Serotonergic Systems 
Voluntary exercise reduces the incidence of stress-related psychiatric disorders in humans and prevents serotonin-dependent behavioral consequences of stress in rodents. Evidence reviewed herein is consistent with the hypothesis that exercise increases stress resistance by producing neuroplasticity at multiple sites of the central serotonergic system, which all help to limit the behavioral impact of acute increases in serotonin during stressor exposure.
PMCID: PMC4303035  PMID: 21508844
wheel running; learned helplessness; anxiety; depression; prefrontal cortex; dorsal raphe nucleus
9.  Electron Paramagnetic Resonance Resolves Effects of Oxidative Stress on Muscle Proteins 
We have used site-directed spin labeling and electron paramagnetic resonance (EPR) to explore the effects of oxidation on muscle function, with particular focus on the actin-myosin interaction. EPR measurements show that aging or oxidative modification cause a decrease in the fraction of myosins in the strong-binding state, which can be traced to the actin-binding cleft of the myosin catalytic domain.
PMCID: PMC3934098  PMID: 24188980
myosin; actin; muscle; Reactive Oxygen Species (ROS); methionine; aging
10.  MRI reveals brain abnormalities in drug-naïve Parkinson’s disease 
Exercise and sport sciences reviews  2014;42(1):10.1249/JES.0000000000000003.
Most brain studies of Parkinson’s disease (PD) focus on patients who are already taking anti-parkinsonian medication. This makes it difficult to isolate the effects of disease from those of treatment. We review MRI evidence supporting the hypothesis that early-stage, untreated PD patients have structural and functional abnormalities in the brain, some of which are related to motor symptoms.
PMCID: PMC3885158  PMID: 24188978
diffusion tensor imaging (DTI); functional magnetic resonance imaging (fMRI); parkinsonism; grip force; subtype; de novo; movement
11.  The Effects of Practice on Coordination 
We review practice-induced changes in two variance components defined based on the uncontrolled manifold hypothesis: One of them affects task performance while the other one does not. Practice leads to a drop in the former component (higher accuracy), while the latter can drop, stay unchanged, or even increase. The last scenario can be achieved with practice that challenges performance stability.
PMCID: PMC3897239  PMID: 24188981
Synergy; practice; variability; redundancy; abundance
12.  Exercise and nutrition to target protein synthesis impairments in aging skeletal muscle 
The loss of skeletal muscle size and function with aging, sarcopenia, may be related, in part, to an age-related muscle protein synthesis impairment. In this review, we discuss to what extent aging affects skeletal muscle protein synthesis and how nutrition and exercise can be strategically employed to overcome age-related protein synthesis impairments and slow the progression of sarcopenia.
PMCID: PMC3790587  PMID: 23873131
Aging; Sarcopenia; Exercise; Protein; Insulin; Muscle Protein Synthesis; mTORC1
13.  How tendons buffer energy dissipation by muscle 
Exercise and sport sciences reviews  2013;41(4):10.1097/JES.0b013e3182a4e6d5.
To decelerate the body and limbs, muscles actively lengthen to dissipate energy. During rapid energy-dissipating events, tendons buffer the work done on muscle by temporarily storing elastic energy, then releasing this energy to do work on the muscle. This elastic mechanism may reduce the risk of muscle damage by reducing peak forces and lengthening rates of active muscle.
PMCID: PMC3836820  PMID: 23873133
Muscle; tendon; elastic energy; energy dissipation; deceleration
14.  Early Exercise Rehabilitation of Muscle Weakness in Acute Respiratory Failure Patients 
Acute Respiratory Failure patients experience significant muscle weakness which contributes to prolonged hospitalization and functional impairments post-hospital discharge. Based on our previous work, we hypothesize that an exercise intervention initiated early in the intensive care unit aimed at improving skeletal muscle strength could decrease hospital stay and attenuate the deconditioning and skeletal muscle weakness experienced by these patients.
Early exercise has the potential to decrease hospital length of stay and improve function in Acute Respiratory Failure patients.
PMCID: PMC3792856  PMID: 23873130
Length of Stay; Physical Function; Mobility; Intensive Care Unit; Strength Training
15.  Circadian Rhythms, skeletal muscle molecular clocks and exercise 
Exercise and sport sciences reviews  2013;41(4):10.1097/JES.0b013e3182a58a70.
Skeletal muscle comprises approximately 40 % of total body mass and, as such, contributes to maintenance of human health. In this review we will discuss the current state of knowledge regarding the role of molecular clocks in skeletal muscle. In addition we discuss a new function for exercise as a time setting cue for muscle and other peripheral tissues.
PMCID: PMC3866019  PMID: 23917214
circadian; skeletal muscle; exercise; peripheral tissues; zeitgeber
16.  Myofilament Protein Alterations Promote Physical Disability in Aging and Disease 
Skeletal muscle contractile function declines with age and age-associated diseases. Although muscle atrophy undoubtedly contributes to this decrease, recent findings suggest that reduced myofilament protein content and function also may participate. Based on these data, we propose that age- and disease-related alterations in myofilament proteins represent one molecular mechanism contributing to the development of physical disability.
PMCID: PMC4171103  PMID: 23392279
myosin; actin; muscle; human; fiber; molecular
17.  The Mechanistic Connection Between the Trunk, Knee, and Anterior Cruciate Ligament Injury 
Neuromuscular control of the trunk and knee predicts anterior cruciate ligament injury risk with high sensitivity and specificity. These predictors are linked, as lateral trunk positioning creates high knee abduction torque (load). The hypotheses explored are that lateral trunk motion increases load and that neuromuscular training that increases trunk control will decrease load.
PMCID: PMC4168968  PMID: 21799427
knee injury; high risk biomechanics; ACL injury prevention; neuromuscular control; female sports injuries; identification of knee injury risk factors
18.  Unraveling the complexities of SIRT1-mediated mitochondrial regulation in skeletal muscle 
SIRT1 is a purported central regulator of skeletal muscle mitochondrial biogenesis. Herein we discuss our recent work utilizing conditional mouse models, which highlight the complexities of SIRT1 biology in vivo, and question its role in regulating mitochondrial function and mitochondrial adaptions to endurance exercise. Further, we discuss the possible contribution of proposed SIRT1 substrates to muscle mitochondrial biogenesis.
PMCID: PMC3707796  PMID: 23792490
Exercise; sirtuins; acetylation; transcription; adaptation
19.  Insulin and Contraction-induced GLUT4 Traffic in Muscle: Insights from a Novel Imaging Approach 
Insulin and contraction-mediated glucose transporter 4 (GLUT4) trafficking have different kinetics in mature skeletal muscle. Intravital imaging indicates that insulin-stimulated GLUT4 trafficking differs between t-tubules and sarcolemma. In contrast, contraction-induced GLUT4 trafficking does not differ between membrane surfaces. This distinction is likely due to differences in the underlying signaling pathways regulating GLUT4 vesicle depletion, GLUT4 membrane fusion and GLUT4 re-internalization.
PMCID: PMC3602324  PMID: 23072821
Living mice; Intravital; In-Vivo; PI3-Kinase; AMP-Kinase; LKB1
20.  Task-Dependent Postural Control Throughout The Lifespan 
Routine activities performed while standing and walking require the ability to appropriately and continuously modulate postural movements as a function of a concurrent task. Changes in task-dependent postural control contribute to the emergence, maturation, and decline of complex motor skills and stability throughout the lifespan.
PMCID: PMC3608710  PMID: 23364347
Postural Control; Stability; Lifespan Development; Multi-task behavior; Mobility; Load Handling; Adaptive Locomotion
21.  Slowed Reaction Time During Exercise: What is the Mechanism? 
PMCID: PMC3661292  PMID: 23392281
22.  Measuring protein synthesis with SUnSET: a valid alternative to traditional techniques? 
Protein synthesis rates are commonly measured by using isotopic tracers to quantify the incorporation of a labelled amino acid into muscle proteins. Here we provide evidence supporting our hypothesis that the non-isotopic SUnSET technique is a valid and accurate method for the measurement of in vivo changes in protein synthesis at the whole muscle and single muscle fiber levels.
PMCID: PMC3951011  PMID: 23089927
skeletal muscle; translation; hypertrophy; atrophy; puromycin; muscle fiber type; myosin heavy chain
23.  The Importance of Pre and Postoperative Physical Activity Counseling in Bariatric Surgery 
There is increasing evidence that physical activity (PA) can enhance weight loss and other outcomes after bariatric surgery. However, most preoperative patients are insufficiently active, and without support, fail to make substantial increases in their PA postoperatively. This review provides the rationale for PA counseling in bariatric surgery and describes how to appropriately tailor strategies to pre- and postoperative patients.
PMCID: PMC3529741  PMID: 22710705
exercise; severe obesity; treatment; clinical care; gastric bypass; laparoscopic adjustable gastric band
24.  Exercise Ventilatory Limitation: The Role Of Expiratory Flow Limitation 
Ventilatory limitation to exercise remains an important unresolved clinical issue; as a result, many individuals misinterpret the effects of expiratory flow limitation as an all-or-nothing phenomenon. Expiratory flow limitation is not all-or-none; approaching maximal expiratory flow can have important effects not only on ventilatory capacity but also on breathing mechanics, ventilatory control, and possibly exertional dyspnea and exercise intolerance.
PMCID: PMC3529766  PMID: 23038244
dynamic compression of the airways; maximal expiratory flow; breathing mechanics; ventilatory limitations to exercise; ventilatory limitations; ventilatory constraints; cardiopulmonary exercise testing
25.  Mobility decline in old age: A time to intervene 
PMCID: PMC3530168  PMID: 23262463

Results 1-25 (76)