Life Sciences Commons^™

Probing Evidence Of Cerebral White Matter Microstructural Disruptions In Ischemic Heart Disease Before And Following Cardiac Rehabilitation: A Diffusion Tensor Mr Imaging Study., Stefan E Poirier, Neville G Suskin, Alexander V Khaw, Jonathan D Thiessen, Joel K Shoemaker, Udunna C Anazodo

Kinesiology Publications

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BACKGROUND: Ischemic heart disease (IHD) is linked to brain white matter (WM) breakdown but how age or disease effects WM integrity, and whether it is reversible using cardiac rehabilitation (CR), remains unclear.

PURPOSE: To assess the effects of brain aging, cardiovascular disease, and CR on WM microstructure in brains of IHD patients following a cardiac event.

STUDY TYPE: Retrospective.

POPULATION: Thirty-five IHD patients (9 females; mean age = 59 ± 8 years), 21 age-matched healthy controls (10 females; mean age = 59 ± 8 years), and 25 younger controls (14 females; mean age = 26 ± 4 years).

FIELD STRENGTH/SEQUENCE: …

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Combining Exercise With Cognitive Training And Vitamin D, Nick W Bray, Frederico Pieruccini-Faria, Suzanne T Witt, Robert Bartha, Timothy J Doherty, Lindsay S Nagamatsu, Quincy J Almeida, Teresa Liu-Ambrose, Laura E Middleton, Louis Bherer, Manuel Montero-Odasso

Kinesiology Publications

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Changes in functional brain connectivity (FBC) may indicate how lifestyle modifications can prevent the progression to dementia; FBC identifies areas that are spatially separate but temporally synchronized in their activation and is altered in those with mild cognitive impairment (MCI), a prodromal state between healthy cognitive aging and dementia. Participants with MCI were randomly assigned to one of five study arms. Three times per week for 20-weeks, participants performed 30-min of (control) cognitive training, followed by 60-min of (control) physical exercise. Additionally, a vitamin D

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Changes In Cognition And Brain Function Following 26 Weeks Of Progressive Resistance Training In Older Adults At Risk For Diabetes: A Pilot Randomized Controlled Trial, Joyla Furlano, Becky Horst, Robert Petrella, Kevin Shoemaker, Lindsay Nagamatsu

Kinesiology Publications

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Introduction

Type 2 diabetes is associated with deficits in cognition and brain health. Individuals with 1 or more risk factors for diabetes (i.e., obesity, prediabetes) already experience some neurocognitive impairment and are at risk for further decline. One way to combat these deficits is through exercise; however, whether resistance exercise can improve these functions in this at-risk group is unknown.

Methods

This study was a pilot randomized controlled trial. Participants were aged 60-80 and had prediabetes (fasting capillary glucose 6.1-6.9 mmol/L) and/or were overweight or obese (body mass index of 25 or above). Participants completed resistance training or balance and …

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Assessment Of Physical Fitness During Pregnancy: Validity And Reliability Of Fitness Tests, And Relationship With Maternal And Neonatal Health - A Systematic Review., Lidia Romero-Gallardo, Olga Roldan Reoyo, Jose Castro-Piñero, Linda E May, Olga Ocón-Hernández, Michelle F Mottola, Virginia A Aparicio, Alberto Soriano-Maldonado

Kinesiology Publications

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Objectives: To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design: A systematic review.

Data sources: PubMed and Web of Science.

Eligibility criteria: Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results: A total of 149 articles containing …

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Differential Behaviour Of Distinct Motoneuron Pools That Innervate The Triceps Surae, Josh W. Cohen, Taian M. Vieira, Tanya D. Ivanova, Jayne Garland

Kinesiology Publications

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It has been shown that when humans lean in various directions, the central nervous system (CNS) recruits different motoneuron pools for task completion; common units that are active during different leaning directions, and unique units that are active in only one leaning direction. We used high-density surface electromyography (HD-sEMG) to examine if motor unit (MU) firing behaviour was dependent on leaning direction, muscle (medial and lateral gastrocnemius; soleus), limits of stability, or whether a MU is considered common or unique. Fourteen healthy participants stood on a force platform and maintained their center of pressure in five different leaning directions. HD-sEMG …

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Influence Of Sex And Age On Muscle Sympathetic Nerve Activity Of Healthy Normotensive Adults, Daniel A. Keir, Mark B. Badrov, George Tomlinson, Catherine F. Notarius, Derek S. Kimmerly, Philip J. Millar, J Kevin Shoemaker, John S. Floras

Kinesiology Publications

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As with blood pressure, age-related changes in muscle sympathetic nerve activity (MSNA) may differ nonlinearly between sexes. Data acquired from 398 male (age: 39±17; range: 18-78 years [mean±SD]) and 260 female (age: 37±18; range: 18-81 years) normotensive healthy nonmedicated volunteers were analyzed using linear regression models with resting MSNA burst frequency as the outcome and the predictors sex, age, MSNA, blood pressure, and body mass index modelled with natural cubic splines. Age and body mass index contributed 41% and 11%, respectively, of MSNA variance in females and 23% and 1% in males. Overall, changes in MSNA with age were sigmoidal. …

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Fifty Years Of Microneurography: Learning The Language Of The Peripheral Sympathetic Nervous System In Humans, J Kevin Shoemaker, Stephen A. Klassen, Mark B. Badrov, Paul J. Fadel

Kinesiology Publications

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As a primary component of homeostasis, the sympathetic nervous system enables rapid adjustments to stress through its ability to communicate messages among organs and cause targeted and graded end organ responses. Key in this communication model is the pattern of neural signals emanating from the central to peripheral components of the sympathetic nervous system. But what is the communication strategy employed in peripheral sympathetic nerve activity (SNA)? Can we develop and interpret the system of coding in SNA that improves our understanding of the neural control of the circulation? In 1968, Hagbarth and Vallbo (Hagbarth KE, Vallbo AB. Acta Physiol …

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Protocol-Dependence Of Middle Cerebral Artery Dilation To Modest Hypercapnia., Baraa K Al-Khazraji, Sagar Buch, Mason Kadem, Brad J Matushewski, Kambiz Norozi, Ravi S Menon, J Kevin Shoemaker

Kinesiology Publications

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There is a need for improved understanding of how different cerebrovascular reactivity (CVR) protocols affect vascular cross-sectional area (CSA) to reduce error in CVR calculations when measures of vascular CSA are not feasible. In human participants, we delivered ∼±4 mm Hg end-tidal partial pressure of CO2 (PETCO2) relative to baseline through controlled delivery, and measured changes in middle cerebral artery (MCA) CSA (7 Tesla magnetic resonance imaging (MRI)), blood velocity (transcranial Doppler and Phase contrast MRI), and calculated CVR based on a 3-minute steady-state (+4 mm Hg PETCO2) and a ramp (-3 to +4 mm Hg of PETCO2). We observed …

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Impact Of Age On Cerebrovascular Dilation Versus Reactivity To Hypercapnia., Nicole S Coverdale, Mark B Badrov, J Kevin Shoemaker

Kinesiology Publications

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This study quantified the effect of age on cerebrovascular reactivity and cerebrovascular conductance while accounting for differences in grey matter volume in younger (YA: n = 12; 24 ± 4 years, six females) and older adults (OA: n = 10; 66 ± 7 years; five females). Cerebral blood flow velocity (CBFV; transcranial Doppler) in the middle cerebral artery (MCA), MCA cross-sectional area (CSA), intracranial volumes (magnetic resonance imaging), and mean arterial pressure (MAP; Finometer), were measured under normocapnic and hypercapnic (6% carbon dioxide) conditions. Cerebral blood flow (CBF) was quantified from CBFV and MCA CSA and normalized to grey matter …

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Effects Of Aging And Coronary Artery Disease On Sympathetic Neural Recruitment Strategies During End-Inspiratory And End-Expiratory Apnea, Mark B. Badrov, Sophie Lalande, T Dylan Olver, Neville Suskin, J Kevin Shoemaker

Kinesiology Publications

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In response to acute physiological stress, the sympathetic nervous system modifies neural outflow through increased firing frequency of lower-threshold axons, recruitment of latent subpopulations of higher-threshold axons, and/or acute modifications of synaptic delays. Aging and coronary artery disease (CAD) often modify efferent muscle sympathetic nerve activity (MSNA). Therefore, we investigated whether CAD (n = 14; 61 ± 10 yr) and/or healthy aging without CAD (OH; n = 14; 59 ± 9 yr) modified these recruitment strategies that normally are observed in young healthy (YH; n = 14; 25 ± 3 yr) individuals. MSNA (microneurography) was measured at baseline and during …

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Increasing Nonsedentary Behaviors In University Students Using Text Messages: Randomized Controlled Trial, Emma Cotten, Harry Prapavessis

Kinesiology Publications

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BACKGROUND: Sedentary behavior (SB) has been linked to many health problems such as type 2 diabetes and heart disease. Increasing the length and frequency of breaks from sitting and increasing the time spent standing and engaged in light and moderate physical activity are ways to decrease SB. Text message-based interventions have succeeded in aiding smoking cessation and increase both physical activity and healthy eating, but they have not been shown to reduce SB.

OBJECTIVE: The primary purpose of this pilot study was to determine the effectiveness of a text message-based intervention in increasing nonsedentary behaviors in university students. A secondary …

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Effects Of Acute And Chronic Interval Sprint Exercise Performed On A Manually Propelled Treadmill On Upper Limb Vascular Mechanics In Healthy Young Men., T Dylan Olver, Steph M Reid, Alan R Smith, Mair Zamir, Peter W R Lemon, M Harold Laughlin, J Kevin Shoemaker

Kinesiology Publications

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Interval sprint exercise performed on a manually propelled treadmill, where the hands grip the handle bars, engages lower and upper limb skeletal muscle, but little is known regarding the effects of this exercise modality on the upper limb vasculature. We tested the hypotheses that an acute bout of sprint exercise and 6 weeks of training induces brachial artery (BA) and forearm vascular remodeling, favoring a more compliant system. Before and following a single bout of exercise as well as 6 weeks of training three types of vascular properties/methodologies were examined in healthy men: (1) stiffness of the entire upper limb …

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Impact Of Long-Term Endurance Training Vs. Guideline-Based Physical Activity On Brain Structure In Healthy Aging, Katelyn N. Wood, Robert Nikolov, J Kevin Shoemaker

Kinesiology Publications

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Brain structure is a fundamental determinant of brain function, both of which decline with age in the adult. Whereas short-term exercise improves brain size in older adults, the impact of endurance training on brain structure when initiated early and sustained throughout life, remains unknown. We tested the hypothesis that long-term competitive aerobic training enhances cortical and subcortical mass compared to middle to older-aged healthy adults who adhere to the minimum physical activity guidelines. Observations were made in 16 masters athletes (MA; 53 ± 6 years, VO2max = 55 ± 10 ml/kg/min, training > 15 years), and 16 active, healthy, and cognitively …

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The Utility Of A Protection Motivation Theory Framework For Understanding Sedentary Behavior, Tiffany S. Wong, Anca Gaston, Stefanie Dejesus, Harry Prapavessis

Kinesiology Publications

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Multilevel determinants of sedentary behavior (SB), including constructs couched within evidence-based psychological frameworks, can contribute to more efficacious interventions designed to decrease sitting time. This study aimed to: (1) examine the factor structure and composition of sedentary-derived protection motivation theory (PMT) constructs and (2) determine the utility of these constructs in predicting general and leisure sedentary goal intention (GI), implementation intention (II), and self-reported SB. Sedentary-derived PMT (perceived severity, PS; perceived vulnerability, PV; response efficacy, RE; self-efficacy, SE), GI, and II constructs, and a modified SB questionnaire were completed by undergraduate students (n = 596). SE was broken into …

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Methods And Considerations For The Analysis And Standardization Of Assessing Muscle Sympathetic Nerve Activity In Humans., Daniel W White, J Kevin Shoemaker, Peter B Raven

Kinesiology Publications

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The technique of microneurography and the assessment of muscle sympathetic nerve activity (MSNA) are used in laboratories throughout the world. The variables used to describe MSNA, and the criteria by which these variables are quantified from the integrated neurogram, vary among studies and laboratories and, therefore, can become confusing to those starting to learn the technique. Therefore, the purpose of this educational review is to discuss guidelines and standards for the assessment of sympathetic nervous activity through the collection and analysis of MSNA. This review will reiterate common practices in the collection of MSNA, but will also introduce considerations for …

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Blood Flow And Muscle Oxygenation During Low, Moderate, And Maximal Sustained Isometric Contractions, Chris Mcneil, Matti D. Allen, Eric Olympico, J Kevin Shoemaker, Charles L. Rice

Kinesiology Publications

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Blood flow and muscle oxygenation during low, moderate, and maximal sustained isometric contractions. Am J Physiol Regul Integr Comp Physiol 309: R475–R481, 2015. First published June 17, 2015; doi:10.1152/ajpregu.00387.2014.—A reduction of blood flow to active muscle will precipitate fatigue, and sustained isometric contractions produce intramuscular and compartmental pressures that can limit flow. The present study explored how blood flow and muscle oxygenation respond to isometric contractions at low, moderate, and maximal intensities. Over two visits, 10 males (26 2 yr; means SD) performed 1-min dorsiflexion contractions at 30, 60, and 100% of maximal voluntary contraction (MVC) torque. Doppler ultrasound of …

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Forebrain Neurocircuitry Associated With Human Reflex Cardiovascular Control., J Kevin Shoemaker, Ruma Goswami

Kinesiology Publications

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Physiological homeostasis depends upon adequate integration and responsiveness of sensory information with the autonomic nervous system to affect rapid and effective adjustments in end organ control. Dysregulation of the autonomic nervous system leads to cardiovascular disability with consequences as severe as sudden death. The neural pathways involved in reflexive autonomic control are dependent upon brainstem nuclei but these receive modulatory inputs from higher centers in the midbrain and cortex. Neuroimaging technologies have allowed closer study of the cortical circuitry related to autonomic cardiovascular adjustments to many stressors in awake humans and have exposed many forebrain sites that associate strongly with …

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Positional Differences In Reactive Hyperemia Provide Insight Into Initial Phase Of Exercise Hyperemia., Jeffrey L Jasperse, J Kevin Shoemaker, Eric J Gray, Philip S Clifford

Kinesiology Publications

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Studies have reported a greater blood flow response to muscle contractions when the limb is below the heart compared with above the heart, and these results have been interpreted as evidence for a skeletal muscle pump contribution to exercise hyperemia. If limb position affects the blood flow response to other vascular challenges such as reactive hyperemia, this interpretation may not be correct. We hypothesized that the magnitude of reactive hyperemia would be greater with the limb below the heart. Brachial artery blood flow (Doppler ultrasound) and blood pressure (finger-cuff plethysmography) were measured in 10 healthy volunteers. Subjects lay supine with …

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Sympathetic Neural Recruitment Strategies: Responses To Severe Chemoreflex And Baroreflex Stress, Mark B. Badrov, Charlotte W. Usselman, J Kevin Shoemaker

Kinesiology Publications

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This study tested the hypothesis that neural coding patterns exist within the autonomic nervous system. We investigated sympathetic axonal recruitment strategies in humans during chemoreflex- and baroreflex-mediated sympathoexcitation using a novel action potential (AP) analysis technique. Muscle sympathetic nerve activity (microneurography) was collected in 11 young individuals (6 females) during baseline and two subsequent protocols: 1) severe chemoreflex stimulation (maximal end-inspiratory apnea following rebreathe), and 2) severe baroreceptor unloading (−80 mmHg lower body negative pressure; LBNP). When compared with each respective baseline, apnea and LBNP increased AP frequency and mean AP content per sympathetic burst (all P < 0.01). When APs were binned according to peak-to-peak amplitude (i.e., into “clusters”), total clusters detected increased during both apnea (Δ7 ± 5; P …

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