Browsing by Subject "Sports Sciences"
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Item Androgens and Cardiovascular Disease(1998-05-01) Dickerman, Rob D.; Walter J. McConathy; Thomas Yorio; Robert GracyDickerman, Rob D., Androgens and Cardiovascular Disease Doctor of Philosophy (Biomedical Sciences), May 1998; 111 pp; 10 tables, bibliography, 197 titles. Anabolic steroids are commonly used by many muscle and strength dependent athletes due to their ability to enhance the hypertrophic effects of resistance training. The use of anabolic steroids by bodybuilders appears to carry significant health risks, most commonly reported are sudden death, myocardial infarction and cardiomyopathy. To investigate the effects of anabolic steroids on cardiovascular risks, a study was designed to analyze the effects of androgens on lipoprotein levels and structure/function of the heart. For the study on lipid-related risk, twelve competitive bodybuilders were recruited for a comprehensive analysis of serum apolipoprotein A-I, B, total cholesterol, HDL-cholesterol, LDL-cholesterol, and testosterone. Serum total cholesterol, HDL- and LDL-cholesterol, apolipoproteins A-I and Be were significantly lower in androgen-users. Consistent with previous reports, androgens were associated with decreases in HDL-cholesterol and apolipoprotein A-I. However, androgens were also associated with reduced serum total cholesterol, LDL-cholesterol and apolipoprotein B. Despite the significantly higher total cholesterol/HDL-cholesterol ratio, the low levels of serum total cholesterol levels (percentile) in the androgen-users raises questions as to whether there is increased risk for cardiovascular disease and the exact role of androgens in cardiovascular risk. To investigate the effects of anabolic steroids in pathologic concentric left ventricular hypertrophy, the effects of androgens on left ventricular size and function were analyzed. Previous investigations conducted on left ventricular size and function have yielded inconclusive results. Problems existing in each of the previous investigations were small body mass, short length of myocardial exposure time to resistance training (years of training), significantly different body mass between steroid-users and steroid-free subjects and monitoring/reporting of steroid use. These problems may have contributed to the discrepancies between studies. Therefore, we selectively recruited eight competitive heavy weight drug-free bodybuilders and eight matched competitive weight bodybuilders on self-directed regimens of anabolic steroids for examination of left ventricular size and function via echocardiography. Increases in left ventricular posterior wall (LVPW) and ventricular septal thickness (VST) were apparent in the steroid-user group (p [less than] 0.05). Ratio of echocardiographic findings to body mass index (BMI) revealed a significantly smaller left ventricular and diastolic dimension (LVDEd/BMI, p [less than] 0.05) in the steroid-user. The smaller LVDEd in steroid-users is coupled with a significantly disproportionate septal and posterior wall thickness in steroid-users. There was no direct evidence of diastolic dysfunction. Thus it appears from these studies that androgens alter lipoproteins leading to a questionable increased risk for cardiovascular disease and may potentiate concentric left ventricular hypertrophy without affecting cardiac function.Item Elimination of Post-Exercise Hypotension Impairs Plasma Volume Recovery(1996-12-01) Hayes, Patrick M.; Peter B. RavenHayes, Patrick M., Elimination of Post-Exercise Hypotension Impairs Plasma Volume Recovery. Master of Science (Biomedical Sciences), December, 1996, 18 pp., 2 tables, 5 figures, bibliography, 20 titles. The aim of this study was to test the hypothesis that plasma volume (PV) recovery following exercise was facilitated by post-exercise hypotension. Seven volunteers performed 2 bouts of cycling exercise for 60 minutes followed by 90 minutes of seated recovery without intervention (trial 1) or with phenylephrine infusion (PE) started at 10 minutes of recovery (trial 2). Blood samples were taken throughout the protocol at specific times, and were analyzed to measure hematocrit (Hct), hemoglobin (Hb), protein content and electrolyte levels. Plasma volume was measured using the Evans Blue Dye dilution technique and estimates of changes from resting values were then calculated from Hct and Hb values. While PV approached baseline levels at 30 minutes into recovery in trial 1, the change in PV remained significantly below control values with PE. We concluded that the diminished gain in the change in total proteins (significant increase without PE, no difference from control with PE) contributed to the impaired recovery of PV observed in trial 2, and that this difference in protein shift is attributable to the elimination of post-exercise hypotension.Item Endurox R4® & Gatorade®: Effects of Recovery Drinks After Prolonged Glycogen-Depleting Exercise(1999-06-01) Williams, Michael Brandon; Raven, Peter B.; Smith, Michael; Shi, XiangrongWilliams, Michael B., Endurox R4® & Gatorade®: Effects of Recovery Drinks After Prolonged Glycogen-Depletion Exercise. Master of Science (Biomedical Sciences, Integrative Physiology), June, 1999, 73 pp., 2 tables, 18 figures, references. Purpose: Eight high-fit (bicycle Vo2max=62.4 ± 1.10 ml·kg-1·min-1) male cyclists, aged 28.4±1.65 yrs, performed a two-hour endurance bicycle exercise to achieve depletion of skeletal muscle and liver glycogen. During recovery, Endurox R4 Recovery Drink®, or Gatorade®, was ingested to investigate their relative restorative capacities to enable further exercise. Methods: Each subject performed two days of testing: one for each drink presented in random order. On each testing day, the twelve-hour fasted subject performed a two-hour cycling exercise bout at 75% VO2max followed by one to three five-minute sprints at 85% VO2max. At the end of the exercise blood glucose concentrations were 3.98±0.138 mmol/L. A four hour recovery period ensued in which the subject was given 24-ounces of the recovery drink. A performance test at 85% VO2max to exhaustion was then conducted. Ventilatory responses were collected breath-to-breath, while venous blood samples were measured for oxidation products, glucose and insulin concentrations. Results: The recovery phase showed significant increases in both plasma glucose and serum insulin following Endurox R4 Recovery Drink® ingestion as compared to Gatorade®. There was a significant increase in time to exhaustion (+55%) following Endurox R4 Recovery Drink® during the performance ride compared to Gatorade®. Final oxidation products following Endurox R4 Recovery Drink® ingestion were significantly decreased as compared to Gatorade® ingestion, in that Thiobarbituric Acid Reactive Substrates (T-BARS) were significantly decreased. Conclusions: These data indicate that the Endurox R4 Recovery Drink®, when compared to Gatorade®, significantly enhanced recovery from glycogen-depleting exercise. In addition, Endurox R4 Recovery® Drink decreased the formation of final oxidation products, when compared to Gatorade®.Item Establishing the Effects of Exercise Schema and Self-Schema on Emotional Distress(2003-08-01) Rodriguez, Leslie R.; Claudia Coggin; Joseph Doster; Daisha CipherRodriguez, Leslie R., BSN, RN, Establishing the Effects of Exercise Schema and Self-Schema on Emotional Distress. Masters of Public Health (Health Behavior), August 2003, 78 pp., 4 tables, references, 81 titles. Chronic diseases’ resulting from anger and depression represents a significant problem. Vast amounts of resources and dollars are expended and utilized. Their link to the development of cardiovascular disease, hypertension, and diabetes is recognized. Physical activity produces improvements in self-esteem, increased alertness, and decreased anxiety. The purpose of this study was determining the effect exercise and exercise schema has on mood states. College age students (N=198) of a large North Texas University were recruited. Data collection included States of change, the Exerciser self-schema questionnaire, Clinical Analysis Questionnaire, and the State Trait Anger Expression Inventory. Significance in some mood states of those who were exercising and exercise schematic were found.Item Examining Coronary Heart Disease Risk Factors and Its Relationship with Physical Activity in a Self-Reported Survey(2004-05-01) Fernandes, Alroy H.; Frederick Fridinger; Daisha Cipher; Claudia CogginFernandes, Alroy H., Examining Coronary Heart Disease Risk Factors and its Relationship with Physical Activity in a Self-Reported Survey. Masters of Public Health (Community Health), May 2004, 49pp., 3 illustrations, references, 38 titles. This study uses ‘Healthstyles,’ a self reported survey of 3,719 respondents above the age of 18, to look at exercise behavior in people at risk for CHD. Married or higher earning individuals were more likely to show sufficient exercise levels. Individuals with high blood pressure, high blood cholesterol, diabetes, obesity or family history of heart disease reported lesser levels of sufficient exercise than those without these conditions. People with CHD risk factor reported lower scores on questions that dealt with attitude and opinions about exercise behavior, and this was significantly correlated with lower levels of sufficient exercise. This supports the ‘positive attributes of the behavior’ aspect of the social cognitive theory of exercise. The attitude questions used, although not specific, could be included in a self-reported survey for the purpose of qualitatively and quantitatively assessing exercise intervention; albeit more studies are required to validate this claim.Item The Effect of Fitness on Cardiac Work with and without Metoprolol(2008-07-01) Hawkins, Megan Nicole; Peter Raven; Michael Smith; Robert MalletHawkins, Megan Nicole, The Effect of Fitness on Cardiac Work with and without Metoprolol. Doctor of Philosophy (Biomedical Science), July 2008; 128 pp; 3 tables; 17 figures; bibliography. Chronic endurance exercise adaptations of the cardiovascular and skeletal muscle systems. The mechanisms by which these adaptations occur, and their effect on the physiological response to exercise, have not been fully elucated. In addition, the classic concept of the role of maximal oxygen consumption (Vo2max) as a parametric index of cardiorespiratory capacity has been questioned. Therefore the purpose of the investigations presented within this dissertation was to: i)retrospectively analyze 156 incremental exercise stress tests and supramaximal exercise tests to verify that VO2 does indeed attain a maximal value; ii)evaluate the effects of cardioselective beta-adrenergic blockade on the ability to maintain cardiac work in average trained and endurance exercise trained subjects during moderate (45% VO2max) and heavy (70% Vo2max) intensity cycling exercise; and iii) determine the effect of aerobic fitness on resting and peak leg vascular conductance and the change in central blood volume observed during the onset of cycling exercise. In the first investigation we demonstrated that highly trained runners capable of maintaining supramaximal workloads achieved a VO2 that rarely exceeded the VO2max value obtained during an incremental exercise stress test. In the second investigation we demonstrated that acute β1-adrenergic receptor (βAR) inhibition reduced cardiac output, cardiac work and cardiac efficiency in endurance trained athletes during moderate and heavy intensity exercise. However, in average trained individuals these same variables were not affected during moderate exercise intensity, but were reduced at heavy intensity exercise. We concluded that βAR blockade impaired the more efficient Frank-Starling mechanism in endurance trained athletes but remained functional in average trained subjects during moderate exercise intensities. In the third investigation we demonstrated that endurance athletes responded to the onset of exercise with a larger increase in central blood volume than average trained individuals. In addition, resting and post-ischemic leg blood glow and leg vascular conductance were greater in the exercise training-induced adaptations of the skeletal muscle vasculature resulted in larger conductance capacity of the working muscle in response to increases in oxygen demand and enabled a greater increase in muscle blood flow from rest to exercise.Item The Prevalence of Behaviors Used to Make & Maintain Weight Among Male Horse Jockeys(2001-05-01) Dodson, Martha A.; Gonzalez, AdelaObjective: Determine the prevalence of weight loss behaviors used by male jockeys to make and maintain weight. Design: An original survey instrument was developed. The pilot study was distributed in a random, anonymous manner. Setting: Lone Star Park, Grand Prairie, Texas and Sunland Park, Sunland Park, New Mexico in December 2000 and January 2001 meetings respectively. Subjects: Twenty-nine male jockeys with a mean age of 34 years and mean racing career of 14 years. Mean weight was 116 pounds, mean height was 66 inches and mean body mass index was 19.6 kg/m2. Twelve jockeys were from Lone Star Park and 17 were from Sunland Park. No female jockeys participated. Results: SPSS Version 10.0 was used for data analysis. The prevalence of current usage of methods to make and maintain weight among the jockeys was 62%. The hot box was used by 85%, diuretics and semi-starvation were each used by 60%, excessive exercise 45% and flipping by 15%. The average number of methods used was 3. The hot box was the primary method used. Two of 20 jockeys felt they had an eating disorder. Conclusion: The prevalence of disordered eating behaviors among male horse jockeys is greater than that for the general male population. Their low mean body mass index may reflect a malnourished state. Pathological eating behaviors can result in a myriad of clinical abnormalities that can be deleterious to a jockey’s health and athletic performance. A national study of jockeys’ methods to make and maintain weight is recommended. Key Words: Eating disorder – disordered eating – weight-loss – athlete – jockeyItem Wearing a Football Helmet Exacerbates Thermal Load During Exercise in Thermoneutral and Hyperthermic Exercise(2004-12-01) Brothers, Robert Matthew; Smith, Michael; Raven, Peter B.; Shi, XiangrongBrothers, Robert Matthew, Wearing a Football Helmet Exacerbates Thermal Load During Exercise in Thermoneutral and Hyperthermic Conditions. Masters of Science (Integrative Physiology), December, 2004, 42 pp., 1 table, 4 illustrations, 55 titles in References. This investigation tested the hypothesis that wearing a football helmet during intense exercise leads to a significant increase in core temperature as indicated by esophageal temperature (Tes), head skin temperature (Th) and heart rate (HR) when compared to a similar bout of exercise performed while no helmet was worn. It was found that in both the helmet and no helmet exercise protocol there was a significant increase in the above variables when compared to baseline. The helmet condition, however, resulted in a significantly greater increase in these variables when compared to the no helmet condition. Furthermore, this effect of the helmet was further increased in a hyperthermic environment when compared to the thermoneutral environment.