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Athlete paradox

Julien Vincent Brugniaux, Geoff B Coombs, Otto F Barak, Zeljko Dujic, Mypinder S Sekhon, Philip N Ainslie
Molecular oxygen (O2 ) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content (CaO2 ), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e...
February 28, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Massimo Negro, Natale Marzullo, Francesca Caso, Luca Calanni, Giuseppe D'Antona
The term doping is generally used to indicate practices based on the use of performance-enhancing drugs (PEDs) or the abuse of medical therapies. Mostly analysed by doctors and officials, doping nevertheless also requires a philosophical consideration to avoid being simplistically portrayed as an isolated practice. To do this, we need to pay attention to the contradictions and paradoxes in the modern approach to doping in sport. In this context, doping is not only relevant to the health of an individual involved in the violation of World Anti-Doping Agency (WADA) criteria, but it actually represents a double-edged phenomenon containing ethical and legal points of view...
February 9, 2018: European Journal of Applied Physiology
Daniel J Owens, Richard Allison, Graeme L Close
The last decade has seen a dramatic increase in general interest in and research into vitamin D, with many athletes now taking vitamin D supplements as part of their everyday dietary regimen. The most recognized role of vitamin D is its regulation of calcium homeostasis; there is a strong relationship between vitamin D and bone health in non-athletic individuals. In contrast, data have consistently failed to demonstrate any relationship between serum 25[OH]D and bone health, which may in part be due to the osteogenic stimulus of exercise...
January 24, 2018: Sports Medicine
Evelyn Zacharewicz, Matthijs K C Hesselink, Patrick Schrauwen
The incidence of obesity and metabolic disease, such as type 2 diabetes mellitus (T2D), are rising globally. Dietary lipid over-supply leads to lipid accumulation at ectopic sites, such as skeletal muscle. Ectopic lipid storage is highly correlated with insulin resistance and T2D, likely due to a loss of metabolic flexibility - the capacity to switch between fat and glucose oxidation upon insulin stimulation - and cellular dysfunction because of lipotoxicity. However, muscle lipid levels are also elevated in endurance trained athletes, presenting a paradoxical phenotype of increased intramuscular lipids along with high insulin sensitivity - the "athletes' paradox"...
January 13, 2018: Journal of Internal Medicine
Michelle S Dotzert, Matthew W McDonald, Michael R Murray, J Zachary Nickels, Earl G Noble, C W James Melling
OBJECTIVES: Abnormal skeletal muscle lipid metabolism is associated with insulin resistance in people with type 1 diabetes. Although lipid metabolism is restored with aerobic exercise training, the risk for postexercise hypoglycemia is increased with this modality. Integrating resistance and aerobic exercise is associated with reduced hypoglycemic risk; however, the effects of this exercise modality on lipid metabolism and insulin resistance remain unknown. We compared the effects of combined (aerobic + resistance) versus aerobic exercise training on oxidative capacity and muscle lipid metabolism in a rat model of type 1 diabetes...
December 4, 2017: Canadian Journal of Diabetes
Yasukazu Yonetani, Yoshio Matsui, Yoshinari Tanaka, Shuji Horibe
Background: The posterior cruciate ligament (PCL) is a primary stabilizer of the knee in the posterior direction. However, PCL deficiency presents a clinical paradox because the outcome of PCL deficiency ranges from total disability to uninterrupted participation in competitive athletics. Purpose: To investigate whether posterior laxity (PL) and the flexion gap (FG) influence the results of the conservative treatment of isolated PCL injuries. Study Design: Case-control study; Level of evidence, 3...
November 2017: Orthopaedic Journal of Sports Medicine
Anne Gemmink, Sabine Daemen, Bram Brouwers, Peter R Huntjens, Gert Schaart, Esther Moonen-Kornips, Johanna Jörgensen, Joris Hoeks, Patrick Schrauwen, Matthijs K C Hesselink
Intramyocellular lipids (IMCL) hamper insulin sensitivity albeit not in endurance-trained athletes (Trained). Compared to type 2 diabetes patients (T2DM), Trained subjects have high levels of Perilipin 5 (PLIN5). Here, we tested if the fraction of PLIN5 coated LDs is a determinant of skeletal muscle insulin sensitivity and contributes to the athlete's paradox. Muscle biopsies were taken from 8 Trained, Lean sedentary, Obese and T2DM subjects. Trained, Obese and T2DM subjects were matched for total IMCL content...
November 7, 2017: Journal of Physiology
Kristina L Johnston, Hannah Bradford, Heather Hodges, Camille M Moore, Emily Nauman, J Tod Olin
INTRODUCTION: Exercise-induced laryngeal obstruction (EILO), the condition previously known as paradoxical vocal fold motion and vocal cord dysfunction, is characterized by inappropriate glottic or supraglottic obstruction during high-intensity exercise, causing exertional dyspnea, frequently with stridor. EILO is definitively diagnosed through upper-airway visualization during a characteristic episode. Although respiratory retraining is a primary therapy for EILO, many patients report symptom persistence despite adequate performance of traditional techniques...
October 11, 2017: Journal of Voice: Official Journal of the Voice Foundation
Sarah Graham, Emily Deardorff, Kristina Johnston, J Tod Olin
Exercise-induced laryngeal obstruction (EILO) is the term for the condition previously named vocal cord dysfunction and paradoxical vocal fold motion. It is defined by glottic or supraglottic obstruction during periods of intense exercise. Not all patients respond to conventional therapy with speech-language pathology, behavioral health interventions, and treatment of contributing conditions. In this edition of Journal of Voice, the authors describe a novel series of respiratory retraining techniques, now called Olin EILOBI (EILO biphasic inspiratory) breathing techniques, specifically designed for athletes with EILO...
October 11, 2017: Journal of Voice: Official Journal of the Voice Foundation
Bryan C Bergman, Leigh Perreault, Allison Strauss, Samantha Bacon, Anna Kerege, Kathleen Harrison, Joseph T Brozinick, Devon M Hunerdosse, Mary C Playdon, William Holmes, Hai Hoang Bui, Phil Sanders, Parker Siddall, Tao Wei, Melissa K Thomas, Ming Shang Kuo, Robert H Eckel
Intramuscular triglyceride (IMTG) concentration is elevated in insulin-resistant individuals and was once thought to promote insulin resistance. However, endurance-trained athletes have equivalent concentration of IMTG compared with individuals with type 2 diabetes, and have very low risk of diabetes, termed the "athlete's paradox." We now know that IMTG synthesis is positively related to insulin sensitivity, but the exact mechanisms for this are unclear. To understand the relationship between IMTG synthesis and insulin sensitivity, we measured IMTG synthesis in obese control subjects, endurance-trained athletes, and individuals with type 2 diabetes during rest, exercise, and recovery...
February 1, 2018: American Journal of Physiology. Endocrinology and Metabolism
Logan K Townsend, Greg L McKie
No abstract text is available yet for this article.
November 15, 2017: Journal of Physiology
Patrick T Gleason, Jonathan H Kim
The benefits of regular and moderate exercise training on cardiovascular outcomes have been well established. In addition, strenuous exercise training leads to corollary cardiac structural and functional adaptations that are sport-specific and facilitate athletic performance. In this review, the normal physiologic and hemodynamic changes that occur during exercise and the subsequent differential exercise-induced cardiac remodeling patterns that develop will be discussed. Paradoxically, recent data have raised concern about the long-term impact of higher doses of physical activity and exercise on mortality and cardiovascular health outcomes...
September 14, 2017: Current Treatment Options in Cardiovascular Medicine
Jan Haut, Christian Gaum
There is a widespread belief that success at the elite level leads to increasing mass participation in sports. However, this assumption is merely supported by empirical evidence and is analyzed here for the case of table tennis. Therefore long-term data (1964-2014) on participation in Germany, France and Austria is statistically tested for effects of success by the countries' athletes at international competitions. Results indicate that no general trickle-down effect can be confirmed for table tennis in the countries observed...
August 2, 2017: Journal of Sports Sciences
Jobert Richie Nansseu, Vicky Jocelyne Ama Moor, Ruth Danielle M Takam, Bertrand Zing-Awona, Marcel Azabji-Kenfack, Francine Tankeu, Corinne M Tchoula, Bruno M Moukette, Jeanne Y Ngogang
BACKGROUND: Elevated titers of antibodies against oxidized low-density lipoproteins-cholesterol (ox-LDL-Ab) have been reported among professional athletes, paradoxically reflecting an increased risk of developing atherogenic and/or cardiovascular events. This study aimed to determine titers of ox-LDL-Ab in a group of Cameroonian professional soccer players, and evaluate their evolution during part of a competition season as well as the plasmatic antioxidant status to find out if this latter correlates with ox-LDL-Ab ...
June 2, 2017: BMC Research Notes
Austin Cole, John L Hiatt, Christopher Arnold, Terry Sites, Ramon Ylanon
BACKGROUND: Chronic exertional compartment syndrome (CECS) is a recognized condition in the lower limb, with many reports in the literature. However, very few instances include CECS of the upper limb. This article presents the case of a collegiate softball pitcher presenting with CECS in her right forearm. To our knowledge, this is the first case report of a softball player with CECS, with only one similar incident in a major league baseball player. PURPOSE: The rarity of this condition normally places it low on the differential diagnosis...
December 2017: Sports Medicine—Open
Kershena S Liao, Paul E Kwak, Hazel Hewitt, Sarah Hollas, Julina Ongkasuwan
OBJECTIVES: Paradoxical vocal fold motion (PVFM) consists of intermittent adduction of the vocal folds during inspiration, resulting in stridor and worsened by anxiety and stress. The purpose of this study was to assess the impact of PVFM on quality of life in our pediatric patient population. STUDY DESIGN: This is a prospective, descriptive survey study. METHODS: Thirty-nine consecutive patients (ages 12-17 years) presenting with a PVFM diagnosis for respiratory retraining sessions with speech-language pathology were recruited...
July 2017: Journal of Voice: Official Journal of the Voice Foundation
Blake Smith, Claudio Milstein, Bryan Rolfes, Samantha Anne
INTRODUCTION: Paradoxical vocal fold motion (PVFM) is a condition in which the vocal cords exhibit inappropriate inspiratory adduction, and it has been poorly studied in the pediatric population. METHODS: Pediatric patients diagnosed with PVCM by a pediatric otolaryngologist and doctor of speech pathology from 2008 to 2012 were reviewed. Patients in whom another cause for their respiratory disturbance was eventually identified were excluded. Patient demographics, characteristics, treatment, and outcomes were reviewed...
March 2017: American Journal of Otolaryngology
Mayra de A Marques, Jose Renato Pinto, Adolfo H Moraes, Anwar Iqbal, Mariana T Q de Magalhães, Jamila Monteiro, Murilo M Pedrote, Martha M Sorenson, Jerson L Silva, Guilherme A P de Oliveira
Hypertrophic cardiomyopathy (HCM) is one of the most common cardiomyopathies and a major cause of sudden death in young athletes. The Ca(2+) sensor of the sarcomere, cardiac troponin C (cTnC), plays an important role in regulating muscle contraction. Although several cardiomyopathy-causing mutations have been identified in cTnC, the limited information about their structural defects has been mapped to the HCM phenotype. Here, we used high-resolution electron-spray ionization mass spectrometry (ESI-MS), Carr-Purcell-Meiboom-Gill relaxation dispersion (CPMG-RD), and affinity measurements of cTnC for the thin filament in reconstituted papillary muscles to provide evidence of an allosteric mechanism in mutant cTnC that may play a role to the HCM phenotype...
February 10, 2017: Journal of Biological Chemistry
Emmanuelle Varlet-Marie, Jean-Frédéric Brun, Eric Raynaud de Mauverger, Christine Fédou
We investigated whether the concept of hematocrit/viscosity (h/η) ratio explains the "paradox of hematocrit in athletes", by calculating a "theoretical optimal hematocrit" (i.e., associated with the higher h/η value predicted with Quemada's equation from plasma viscosity, and erythrocyte rigidity index) before and after exercise. 14 rugby players (19-31 yr; weight 65.8-109.2 kg; height 1.7-1.96 m; BMI 21.7-33.1 kg/m2) underwent a standardized submaximal exercise session on cycloergometer corresponding to 225 kjoules over 30 min...
2016: Clinical Hemorheology and Microcirculation
Nirit Geva, Jens Pruessner, Ruth Defrin
INTRODUCTION: Triathletes, who constantly engage in intensely stressful sport, were recently found to exhibit greater pain tolerance and more efficient pain inhibition capabilities than nonathletes. However, pain inhibition correlated negatively with retrospective reports of mental stress during training and competition. The aim of the current study was to test pain inhibition capabilities of triathletes under acute, controlled psychological stress manipulation. METHODS: Participants were 25 triathletes and ironman triathletes who underwent the measurement of pain threshold, pain intolerance, tonic suprathreshold pain, and conditioned pain modulation before and during exposure to the Montreal Imaging Stress Task (MIST)...
February 2017: Medicine and Science in Sports and Exercise
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