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Full-Text Articles in Physiology

Microglial Response To Glucocorticoids During Chronic Sleep Fragmentation, Christian Chelson Aug 2023

Microglial Response To Glucocorticoids During Chronic Sleep Fragmentation, Christian Chelson

Masters Theses & Specialist Projects

Sleep is one of the body’s greatest and most basic needs. Chronic sleep loss (<6 hours a day) is linked to many cardiovascular issues, diabetes, and inflammatory conditions and has been shown to lower life expectancy. Obstructive sleep apnea (OSA) is a complication that causes sleep fragmentation in >8% of adults from developed countries, and many with OSA may be unaware of their condition. Having long-term OSA is linked to neuroinflammation caused by activated microglia in the brain, but the mechanics of this inflammation are not well understood. It is known that glucocorticoids, steroid hormones produced and released from the adrenal glands, have a suppressive effect on microglia. The purpose of this study is to explore the role that glucocorticoids have upon microglia activation induced by chronic sleep fragmentation (SF). C57BL/6J mice were …


Effects Of Glucocorticoids Upon Pro-Inflammatory Responses To Acute Sleep Fragmentation, Hunter Weaver May 2022

Effects Of Glucocorticoids Upon Pro-Inflammatory Responses To Acute Sleep Fragmentation, Hunter Weaver

Masters Theses & Specialist Projects

Sleep loss is a common problem in humans who suffer from obstructive sleep apnea. Sleep aids in the regulation of immune responses, some of which induce inflammatory responses. Cytokines regulate the inflammatory process and are released in response to sleep fragmentation (SF) in mice. Glucocorticoids are hormones that are released from the adrenal cortices during a stress response and are considered to be anti-inflammatory and immunosuppressive at high doses but may stimulate immune function on an acute level. The first hypothesis tested was that normal physiological expression of glucocorticoids (Sham) will display increased IL-1β and TNFα expression levels, while high …


The Effect Of Freeze-Thaw Events On Dna Integrity In The Gray Treefrog (Hyla Versicolor), Georgia Ficarra Jul 2021

The Effect Of Freeze-Thaw Events On Dna Integrity In The Gray Treefrog (Hyla Versicolor), Georgia Ficarra

Masters Theses & Specialist Projects

Freeze-tolerant gray treefrogs survive winter by producing natural cryoprotectants and accommodating ice formation within extracellular spaces. While frozen, gray treefrogs endure hyperglycemia, dehydration, and anoxia due to the halt of all bodily functions. Upon thawing, the frogs’ anoxic cells receive a rapid influx of oxygen, which can cause oxidative damage to vital macromolecules including DNA. Previous studies have suggested freeze-tolerant frogs avoid oxidative damage after freeze-thaw events by elevating antioxidant activity, but recent work has shown upregulated DNA repair encoding genes in post-freeze frogs. The objective of this thesis is to assess the cellular costs of freezing by measuring oxidative …


Does Infant Temperament And Parental Involvement Influence Infant Cardiac Physiological Regulation?, Mary Richter Apr 2020

Does Infant Temperament And Parental Involvement Influence Infant Cardiac Physiological Regulation?, Mary Richter

Masters Theses & Specialist Projects

The ability to self-regulate allows infants to stay at a baseline level during periods of stress (Porges, 1995). Baseline respiratory sinus arrhythmia (RSA) may be used as an indicator of self-regulation and how well an individual can respond to changes in the environment (Stifter & Corey, 2001). Differences in infant temperament can influence a child’s ability to self-regulate (Dale et al., 2011), but moderators of this relationship have not been thoroughly examined in the literature. Parents who are more involved might have more opportunities to teach children important regulatory strategies (Blandon et al., 2010). The current study examined the association …


Effects Of Pharmacologically-Induced Sleep Loss On Parental Care In Arctic-Breeding Songbirds, Wesley Payette Apr 2020

Effects Of Pharmacologically-Induced Sleep Loss On Parental Care In Arctic-Breeding Songbirds, Wesley Payette

Masters Theses & Specialist Projects

Sleep loss is well known to impair cognitive function, immunological responses, and general well-being in humans. However, sleep requirements in mammals and birds may vary dramatically, especially with changes in environment. In circumpolar regions with continuous light, sleep requirements may be little, particularly in breeding birds. The effects of sleep loss on several fitness parameters were examined in two species of Arctic-breeding passerine birds: Lapland longspurs (Calcarius lapponicus) and snow buntings (Plectrophenax nivalis). Adult males were implanted during the nestling phase (4 days post-hatch) with osmotic pumps containing an anti-narcolepsy drug, modafinil, to extend the active period for 72 h. …


Validation Of A Novel Vo2max Protocol, Griffin Green Apr 2020

Validation Of A Novel Vo2max Protocol, Griffin Green

Masters Theses & Specialist Projects

Though there are several to choose from, the Bruce protocol is the most commonly utilized treadmill protocol when assessing maximal oxygen consumption (VO2max). Originally developed for cardiac patients, the Bruce protocol may not be an appropriate treadmill protocol for young or trained individuals with higher levels of cardiorespiratory fitness. The steep grade used often leads localized muscular fatigue, which may cause participants to end the test prior to reaching their true VO2max. Another popular protocol, the Astrand, also utilizes a steep grade, but the speed remains constant. Similar to the Bruce, the Astrand protocol may not prompt a maximal cardiovascular …


Effects Of Evidence-Based Materials And Access To Local Resources On Physical Activity During Pregnancy, Kolbi Edens Apr 2019

Effects Of Evidence-Based Materials And Access To Local Resources On Physical Activity During Pregnancy, Kolbi Edens

Masters Theses & Specialist Projects

Physical activity (PA) during pregnancy has been shown to be safe and effective for improving maternal and infant health; however, only 23% of pregnant women exercise in accordance with guidelines. PURPOSE: To determine if the distribution of evidence-based educational resources as well as access to community resources will increase PA levels as well as knowledge/beliefs about PA during pregnancy. METHODS: Participants (8-12 weeks) completed assessments concerning their activity levels, as well as knowledge/beliefs regarding PA, during pregnancy. Next, participants were randomly assigned to either an intervention (IG) or control group (CG). The IG received educational information regarding PA during pregnancy, …


Interactions Between Aerobic Exercise Volume, Academic Stress, And Immune Function, Teresa Wiczynski Apr 2018

Interactions Between Aerobic Exercise Volume, Academic Stress, And Immune Function, Teresa Wiczynski

Masters Theses & Specialist Projects

Many college students exercise individually or participate in collegiate and intramural sports in addition to fulfilling their stressful academic requirements. The combination of accumulated stress and vigorous exercise could result in an impaired immune system, prompting the onset of disease and absences in class and sports practice.

Twenty-six male and female participants aged 18 to 23 were recruited for this study. Over the course of an academic semester, participants completed weekly electronic surveys documenting stress levels, aerobic exercise, and symptoms related to upper respiratory tract infections. Participants were evaluated at four different time points (Baseline, Post-Midterm Exam, Baseline Reassessment, and …


The Impact Of Invasive Lionfish On The Feeding Performance Of Endemic Spotted Scorpionfish, Nathaniel Zbasnik Apr 2018

The Impact Of Invasive Lionfish On The Feeding Performance Of Endemic Spotted Scorpionfish, Nathaniel Zbasnik

Masters Theses & Specialist Projects

Invasive species, such as the red lionfish, Pterois volitans, are damaging many ecosystems around the world by out-competing native species. However, little work has been done to determine if P. volitans have a direct influence on the feeding performance of native species with which they compete. This study examines the feeding performance in terms of suction pressure, kinematic timing, and excursion distances of spotted scorpionfish, Scorpaena plumieri. Through multiple trials it was examined how S. plumieri modulate their kinematic behavior in response to P. volitans and a conspecific. The creation of a smaller buccal cavity and a decrease in time …


The Mechanism Of Biotremor Production In The Veiled Chameleon (Chamaeleo Calyptratus), Samuel Tegge Apr 2018

The Mechanism Of Biotremor Production In The Veiled Chameleon (Chamaeleo Calyptratus), Samuel Tegge

Masters Theses & Specialist Projects

Vibratory communication has evolved in numerous animal groups, including insects, spiders, fishes, mammals, and was recently discovered in veiled chameleons (Chamaeleo calyptratus). I examined the mechanism by which C. calyptratus produce these biotremors. Muscle activity data were gathered during simulated anti-predator responses via electromyography (EMG) with simultaneous recordings of biotremor production using an accelerometer. I correlated EMG data with the accelerometer data to implicate the muscles responsible for the production of the biotremors. Mixed-effect linear regression models described the mechanism, and a model selection framework determined which model fit the data best. I then used an analysis of variance to …


The Relationship Between The Metabolic Responsiveness To A High-Fat Meal And An Acute Bout Of Moderateintensity Exercise Among Postpartum Women, Apoorva Tadakaluru Apr 2018

The Relationship Between The Metabolic Responsiveness To A High-Fat Meal And An Acute Bout Of Moderateintensity Exercise Among Postpartum Women, Apoorva Tadakaluru

Masters Theses & Specialist Projects

Background: There has been very little research regarding the metabolic health of women during the postpartum period. Metabolic flexibility is the physiological ability to alter substrate oxidation in response to substrate availability and is a good indicator of overall metabolic health. Metabolic flexibility can be assessed by placing metabolic demands on the body and observing metabolic responsiveness- two examples of such metabolic stressors are lipid oxidation rates in response to a high-fat meal and as well as exercise. However, it is unknown whether postpartum women will respond similarly to these two different types of metabolic stressors. This information will allow …


Metabolic Flexibility Among Women After A Single High Fat Meal, Alyssa Olenick Apr 2017

Metabolic Flexibility Among Women After A Single High Fat Meal, Alyssa Olenick

Masters Theses & Specialist Projects

PURPOSE: Obese women have increased rates of metabolic diseases compared to those of healthy weight status. Additionally, African-American (AA) women have higher rates of metabolic disease compared to Caucasian (CA) women. Metabolic inflexibility is the inability to adjust substrate oxidation in response to dietary intake; potentially leading to weight gain and the development of metabolic disease. Few studies have investigated the impact of weight status and/or ethnicity on the metabolic response of women to a single high fat meal. An acute unfavorable metabolic response may contribute to the higher incidence of metabolic disease among not only obese, but also AA …


Effects Of Sleep Fragmentation On The Immune System Of Zebra Finches Using Cytokine Gene Expression, Laken N. Cooper Jul 2016

Effects Of Sleep Fragmentation On The Immune System Of Zebra Finches Using Cytokine Gene Expression, Laken N. Cooper

Masters Theses & Specialist Projects

Sleep loss is known to trigger an inflammatory response and increase serum corticosterone in both human and murine models. However, very little evidence is available on the potential effects of sleep loss in avian models. This study aims to construct a profile using cytokine gene expression data to determine how birds respond to sleep loss in a controlled environment. I investigated changes in pro-inflammatory (IL-1β and IL-6) and anti-inflammatory (IL-10) cytokine gene expression in the periphery (fat, liver, spleen, and heart) and brain (hypothalamus, hippocampus, and apical hyperpallium) in zebra finches exposed to a novel sleep fragmentation method. Serum corticosterone, …


Melanin As An Oto-Protective Pigment In Two Fish Species: Poecilia Latipinna And Cyprinus Carpio , Bethany N. Coffey Aug 2014

Melanin As An Oto-Protective Pigment In Two Fish Species: Poecilia Latipinna And Cyprinus Carpio , Bethany N. Coffey

Masters Theses & Specialist Projects

Melanin is the dark pigment found in most organisms that gives color to the skin, hair, feathers, and eyes of vertebrates. While melanin is known to also be present in the stria vascularis of the mammalian cochlea, its function in the inner ear is still unknown. Some previous studies have indicated that melanin may serve to protect the mammalian ear from hearing loss. Minimal previous research on melanin within the inner ears of fishes has been conducted. In this study, the melanin levels in the inner ears of different color morphs of two fish species (Poecilia latipinna and Cyprinus …


Single Nucleotide Polymorphisms Linked To Essential Hypertension In Kasigau, Kenya, Julia Carol Freeman Dec 2013

Single Nucleotide Polymorphisms Linked To Essential Hypertension In Kasigau, Kenya, Julia Carol Freeman

Masters Theses & Specialist Projects

Hypertension, or high blood pressure (BP), is an ever-growing epidemic in the developing world. Understanding the genetics behind essential hypertension (EH), or hypertension with no known cause, is especially important. In this study, three single nucleotide polymorphisms (SNPs) known to be linked to an increase in susceptibility to EH were quantified from a cohort of Kenyans living in the Kasigau region. The SNPs are located in three genes that are part of the renin angiotensin system, the primary regulatory pathway in humans controlling BP. They include: AGT (rs699), AGTR1 (rs5186), and HSD11β2 (rs5479). Overall, by using a fluorescent-based RT-PCR technique, …


The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration, Yajie Wang May 2012

The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration, Yajie Wang

Masters Theses & Specialist Projects

Growth hormone (GH) was upregulated in the zebrafish inner ear following sound exposure in a previous study. To identify the specific role of GH in hair cell regeneration and the possible cellular mechanisms of this regeneration, groups of zebrafish were divided into baseline (no sound exposure, no injection), buffer-injected and GH-injected groups. Buffer- and GH-injected fish were exposed to a 150 Hz tone at a source level of 179 dB re 1 μPa root mean squared (RMS) for 36 h. Phalloidin-staining was used to assess the effects of GH on hair cell bundle density; BrdU-labeling was used to assess the …


Regulation Of Endothelial Nitric Oxide Synthase In Pulmonary Myofibroblasts, Jonathan David Faughn Aug 2011

Regulation Of Endothelial Nitric Oxide Synthase In Pulmonary Myofibroblasts, Jonathan David Faughn

Masters Theses & Specialist Projects

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease leading to decreased lung volume and eventual respiratory failure. At present, the median post-diagnosis lifespan is between three and six years. Myofibroblasts are collagen-secreting cells essential for wound healing, but also implicated in the fibroproliferation and extra cellular matrix deposition commonly seen in IPF. The nitric oxide (NO) signaling pathway is implicated in protomyofibroblast to myofibroblast transition and regulation. Previous work has shown that in pulmonary myofibroblasts, endothelial nitric oxide synthase (eNOS) is the primary NOS isoform expressed. The current study used cultured rat pulmonary myofibroblasts between passages two and five …


Cloning Of A Chlamydomonas Reinhardtii Marker Into A Rna Interference Construct To Test Whether The Photoreceptor Chlamyrhodopsin Is Involved In Circadian Clock Resetting, Shravya Reddy Maddi Dec 2010

Cloning Of A Chlamydomonas Reinhardtii Marker Into A Rna Interference Construct To Test Whether The Photoreceptor Chlamyrhodopsin Is Involved In Circadian Clock Resetting, Shravya Reddy Maddi

Masters Theses & Specialist Projects

Chlamydomonas reinhardtii, a unicellular eukaryotic green alga, serves as a model organism to study the circadian clock in plants and animals. Rhodopsins are blue/green-light photoreceptors also found in C. reinhardtii. Chlamyrhodopsin (COP), the most abundant eyespot protein, was reported to have no role in the phototactic and photophobic responses in C. reinhardtii. Its function is yet unknown.
In the present study, we hypothesized that the function of COP is to mediate entrainment of the circadian clock by light. In order to test this hypothesis, a C. reinhardtii selection marker conferring resistance to the antibiotic paromomycin was cloned …


Computational Prediction Of The Agregated Structure Of Denatured Lysozyme, Pongsathorn Chotikasemsri Dec 2009

Computational Prediction Of The Agregated Structure Of Denatured Lysozyme, Pongsathorn Chotikasemsri

Masters Theses & Specialist Projects

Mis-folded proteins and their associated aggregates are a contributing factor in some human diseases. In this study we used the protein lysozyme as a model to define aggregation structures under denaturing conditions. Sasahara et al. (2007), Frare et al. (2009, 2006), and Rubin et al. (2008) observed conditions where heat denatured lysozyme formed fibril structures that were observed to be 8-17 nanometers in diameter under the electron microscope. Even though the crystal structure of lysozyme is known, the denatured form of this protein is still unknown. Therefore, we used Rosetta++ protein folding and blind docking software to create in silico …


Effects Of A Topical Analgesic Using Massage On Delayed Onset Muscle Soreness, Carrie E. Varvil Dec 2009

Effects Of A Topical Analgesic Using Massage On Delayed Onset Muscle Soreness, Carrie E. Varvil

Masters Theses & Specialist Projects

No abstract provided.


Adding Upstream Sequence And A Downstream Reporter To The Bile Acid Inducible Promoter Of Clostridium Scindens Vpi 12708, Bryan Patrick Mason Aug 2009

Adding Upstream Sequence And A Downstream Reporter To The Bile Acid Inducible Promoter Of Clostridium Scindens Vpi 12708, Bryan Patrick Mason

Masters Theses & Specialist Projects

Bile acids in the small intestines of animals serve to breakdown fats and fatsoluble vitamins. Most of the bile acids are reabsorbed into the enterohepatic circulation, but approximately five percent of these bile acids pass into the large intestine. These bile acids are swiftly deconjugated by the bacterial population, and then subjected to further intestinal bacterial chemical modifications. The most significant of these modifications are 7α-dehydroxylations which form secondary bile acids (deoxycholate and lithocholate). Much research has illuminated the 7α-dehydroxylation pathway: of particular interest is the bile acid inducible operon, for which Clostridium scindens VPI 12708 serves as the model …


The Effects Of Repeated Anaerobic Bouts On Immune Parameters, James C. Sivley Aug 2009

The Effects Of Repeated Anaerobic Bouts On Immune Parameters, James C. Sivley

Masters Theses & Specialist Projects

To date, the exercise-induced immune response in has only been evaluated in subjects performing aerobic exercise. The primary purpose of this study is to determine if repeated bouts of anaerobic exercise will induce a similar immune response in human subjects as exhibited by aerobic exercise. Secondary to immune function, an analysis of performance from trial to trial will be made. Nine males between the ages of 18-25 were selected on a volunteer basis to participate in this study. Subjects performed Wingate tests set in 3 series with 120 seconds between trials within series and 405 seconds between series for an …


Effects Of Exercise Induced Fatigue On Postural Balance: A Comparison Of Treadmill Versus Cycle Fatiguing Protocols, Katherine Wright May 2008

Effects Of Exercise Induced Fatigue On Postural Balance: A Comparison Of Treadmill Versus Cycle Fatiguing Protocols, Katherine Wright

Masters Theses & Specialist Projects

The purpose of this study was to examine the effects of muscle fatigue after a treadmill versus cycle ergometer incremental test on postural balance indices and recovery time recreationally trained individuals. The Bruce Treadmill Test and the Incremental Cycle Ergometer test were used to induce fatigue. Each subject (N=16) performed both exercises, but the order of the exercises was randomized. The subjects performed balance measures on a Biodex Balance System via the Dynamic Balance Test at level 5 and indices were recorded as given. Balance was measured a total of nine times (pre-exercise, immediately post, and at 3, 6, 9, …


Similarities Between Etiological Models Of Eating Disorder Symptomatology And Muscle Dysmorphia Symptomatology, Jennifer Jonda May 2007

Similarities Between Etiological Models Of Eating Disorder Symptomatology And Muscle Dysmorphia Symptomatology, Jennifer Jonda

Masters Theses & Specialist Projects

Muscle Dysmorphia (MD) has recently been conceptualized as the male form of Eating Disorders (ED), although it is not currently classified as an ED. The current study compares etiological models of MD symptomatology (based on Grieve's [2007] conceptual model of MD) and ED symptomatology (based on Stice's [1994] conceptual model of Bulimia Nervosa). In both models, it was hypothesized that sociocultural influences on appearance (SIA) would predict body dissatisfaction (BD), and that this relationship would be mediated by self-esteem (SE) and perfectionism (P); that BD would predict negative affect (NA); and that NA would predict MD and ED symptomatology. Two-hundred-forty-seven …


The Effect Of Varying Cadence In Cycle Ergometry On Submaximal Predictions Of Peak Oxygen Uptake, Zachary Callahan Aug 2006

The Effect Of Varying Cadence In Cycle Ergometry On Submaximal Predictions Of Peak Oxygen Uptake, Zachary Callahan

Masters Theses & Specialist Projects

The purpose of this study was to investigate the effect that varying cadence had on the ability of a submaximal cycle ergometry test to accurately predict peak oxygen uptake (VO2) using the standard YMCA protocol workloads. There has been limited scholarship investigating the effect that varying cadence has on trained cyclists and almost none on untrained participants. For this study twelve moderately healthy participants (age: 20.75 ± 1.87, body fat: 15.8 ± 4.91 %) who did not use cycling as part of their workout regime performed a peak VO2 cycle test and three randomized submaximal tests. The three submaximal tests …


Improving The Accuracy Of The Vo2 Max Prediction Obtained From Submaxial Ymca Testing, Lindsay Parson Dec 2004

Improving The Accuracy Of The Vo2 Max Prediction Obtained From Submaxial Ymca Testing, Lindsay Parson

Masters Theses & Specialist Projects

Maximal oxygen uptake (VO2 max) is the best criterion measure for aerobic fitness and the prescription of exercise intensity for programs designed to enhance cardiorespiratory fitness. There are two ways of obtaining VO2 max: maximal tests, which require subjects to exercise to the point of volitional exhaustion and provide the most accurate measure; and submaximal tests, which are less physically strenuous but have lower accuracy. A popular submaximal protocol is the YMCA bike test. Steady state heart rate (HR) is measured at multiple submaximal workloads and extrapolated to the subject's estimated maximal HR (220-age). The VO2 corresponding to the estimated …


The Influence Of Music On Preferred Intensity And Associated Physiological Responses, David Nuckols Nov 2003

The Influence Of Music On Preferred Intensity And Associated Physiological Responses, David Nuckols

Masters Theses & Specialist Projects

Music is a part of everyday life and has an effect on people in many different ways. Music can be as individual as the person who listens to it, and thus there are many genres for many different tastes. Music has accompanied exercise and sport for quite some time. It has been shown to have varying psychophysical effects including decreasing ratings of perceived exertion (RPE) at a given sub-max intensity, enhancing arousal control, and affective states at high and medium intensities. Also the improved synchronization of sub-maximal exercise with music may result in increased work output. The proposed ability of …


Acute Cardiovascular Response And Perception Of Effort Between The Super Slow And Gold Standard Resistance Training Protocols, Phillip Wickwire Jul 2003

Acute Cardiovascular Response And Perception Of Effort Between The Super Slow And Gold Standard Resistance Training Protocols, Phillip Wickwire

Masters Theses & Specialist Projects

Super Slow training was proposed by Ken Hutchins in a book entitled Super Slow: The Ultimate Exercise Protocol (1992). Since then Super Slow training has been proposed to improve strength more effectively than traditional resistance training and improve cardiovascular measures above aerobic exercise. However, whether this type of training is safe for the older, possibly hypertensive population to which it is being targeted is questionable. To help provide an answer to this question the purpose of this study was to measure blood pressure, heart rate (HR), and ratings of perceived exertion (RPE) while performing the Super Slow resistance training protocol …


Rpe "Drift" In Fit And Unfit Males Cycling In A Hot And Cool Environment, Robert Pritchett May 2003

Rpe "Drift" In Fit And Unfit Males Cycling In A Hot And Cool Environment, Robert Pritchett

Masters Theses & Specialist Projects

The potential influence of aerobic fitness on RPE estimations during extended exercise bouts is not well understood. The current study compared RPE-Overall, RPE-Legs and RPE-Chest between fit (n=7) and unfit (n=6) males. Subjects completed a graded cycling test and then, in a counterbalanced order, on two separate days cycled for 60min (intensity~90% of the Onset of Blood Lactate Accumulation (OBLA) - determined via gas exchange indices) at 30}1 degrees Wet Bulb Globe Temperature (WBGT) and 18}1 degrees WBGT. Heart rate (HR), rectal temperature (Tree) and overall and differentiated RPE estimations were collected every 5 minutes. Repeated measures analyses of variance …


Effects Of Two Backpack Weight Distributions On Perceptual And Physiological Measures During Walking, Katelyn Wells-Fahling Jul 2002

Effects Of Two Backpack Weight Distributions On Perceptual And Physiological Measures During Walking, Katelyn Wells-Fahling

Masters Theses & Specialist Projects

Backpack weight distribution may affect economy by conserving energy and thus potentially prolonging fatigue. Research has not however examined effects of backpack weight distribution on subjective measures of intensity and comfort. Heart rate (HR) and overall and differentiated Ratings of Perceived Exertion (RPE) were examined during simulated backpacking with differentially weighted backpacks. Volunteers (n=27) completed two simulated hiking trials on a treadmill. Trials consisted of 15 minutes walking at 0% grade followed by 15 minutes walking at 10% grade at 2.5 mph (males) or 2.0 mph (females). Subjects wore an internal frame backpack packed to contain 25% of their individual …