glycogen and Athletic-Injuries

Traditionally, ultrasound has been used to evaluate musculoskeletal injuries in athletes; however, ultrasound applications extend well beyond musculoskeletal conditions, many of which are pertinent to athletes.. Articles were identified in PubMed using the search terms ultrasound, echocardiogram, preparticipation physical examination, glycogen, focused assessment with sonography of trauma, optic nerve, and vocal cord dysfunction. No date restrictions were placed on the literature search.. Clinical review.. Level 4.. Several potential applications of nonmusculoskeletal ultrasound in sports medicine are presented, including extended Focused Assessment with Sonography for Trauma (eFAST), limited echocardiographic screening during preparticipation physical examinations, assessment of muscle glycogen stores, optic nerve sheath diameter measurements in athletes with increased intracranial pressure, and assessment of vocal cord dysfunction in athletes.. Ultrasound can potentially be used to assist athletes with monitoring their muscle glycogen stores and the diagnosis of multiple nonmusculoskeletal conditions within sports medicine.

Topics: Athletic Injuries; Echocardiography; Glycogen; Heart Defects, Congenital; Humans; Intracranial Hypertension; Muscle, Skeletal; Optic Nerve; Physical Examination; Sports Medicine; Ultrasonography; Vocal Cord Dysfunction

The use of alcohol is often intimately associated with sport. As well as providing a source of energy, alcohol (ethanol) has metabolic, cardiovascular, thermoregulatory, and neuromuscular actions that may affect exercise performance. Strength is minimally affected, and performance impairments depend on the dose of alcohol and subject habituation to alcohol intake, exercise duration, environmental conditions, and other factors. Central nervous system function is impaired at high doses, resulting in decrements in cognitive function and motor skill, as well as behavioral changes that may have adverse effects on performance. Effects may persist for hours after intoxication.

Topics: Alcohol Drinking; Athletic Injuries; Body Temperature Regulation; Central Nervous System Depressants; Cognition; Ethanol; Exercise; Glycogen; Humans; Motor Skills; Sports; Task Performance and Analysis; Water-Electrolyte Balance

Topics: Adolescent; Adrenal Glands; Adult; Age Factors; Animals; Athletic Injuries; Blood Glucose; Cardiovascular Physiological Phenomena; Child; Dogs; Environmental Exposure; Enzymes; Exercise Test; Fatty Acids; Female; Glycogen; Gymnastics; Humans; Lactates; Male; Methods; Physical Exertion; Proteins; Pyruvates; Rats; Rats, Inbred Strains; Research; Respiratory Physiological Phenomena; Sports; Thyroid Gland; Time Factors

In untrained subjects, strenuous exercise provokes the appearance of oxidant stress markers in blood and muscle. On the other hand, trained muscle is resistant to oxidant stress unless exercise challenges the muscle glycogen supply. It is not known whether chronic high-intensity exercise alters the susceptibility of skeletal muscle to oxidant stress, whether there are gender-related differences in markers of oxidant stress, or whether elevating muscle glycogen stores by increasing dietary carbohydrate can minimize any exercise-related oxidant stress. To address these issues, collegiate rowers (12 men, 11 women) were randomly assigned to a moderate-(MOD, 5 g/kg body wt) or high-carbohydrate (HI, 10 g/kg) diet in a double-blind design and underwent strenuous training for 4 wk. Training in the A.M. was 40 min at 70% maximal O2 consumption (VO2); in the P.M. it was either three 2,500-m time trials (to assess power output) or aerobic and lactate tolerance training. Total daily training time was 65 min at 70% maximal VO2 and 38 min at > or = 90% maximal VO2. Thrice-weekly morning blood samples were assayed for serum creatine kinase (CK), plasma thiobarbituric acid-reactive substances (TBARS), and serum beta-glucuronidase (beta-Gluc). Weekly muscle biopsies were obtained for analysis of glycogen and, when tissue sample quantity allowed, TBARS. HI rowers produced more power and improved power more (10.7 +/- 1.0 vs. 1.6 +/- 1.6%) over the 4 wk than did the MOD rowers. Preexercise muscle glycogen concentration was maintained at 119 mmol/kg in MOD but increased 65% in HI rowers (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Athletic Injuries; Biomarkers; Cell Membrane Permeability; Creatine Kinase; Dietary Carbohydrates; Double-Blind Method; Female; Glycogen; Humans; Male; Muscles; Oxidants; Oxygen Consumption; Physical Education and Training; Sex Characteristics; Stress, Physiological; Thiobarbituric Acid Reactive Substances

We examined the effect of early-onset of muscle damage and low muscle glycogen on cardiorespiratory and metabolic responses to low-intensity exercise.. Twelve men cycled for 10 min at 50% maximal oxygen uptake before, and 12 h after a morning downhill run (five, 8 min bouts at -12% gradient, with 2 min rests) under normal (NORM) and lowered glycogen (LOW) conditions, following a cross-over design with conditions separated by six weeks. Cardiorespiratory responses were recorded, with oxidation measures derived from stoichiometry equations.. Muscle damage symptoms post-downhill (0 h) were similar between conditions. Carbon dioxide ventilatory equivalent increased 12 h post-downhill for LOW (P<0.05), but not NORM (P=0.7). A trend towards decreased respiratory exchange ratio (RER) was shown 12 h post-downhill for LOW (1.00±0.07 to 0.89±0.12, P=0.06), but not NORM (0.94±0.11 to 0.94±0.08; P=0.6). Twelve hours after LOW downhill running fat oxidation increased (0.21±0.18 g·min-1 to 0.36±0.27 g·min-1; P<0.05) and carbohydrate oxidation decreased (2.68±0.52 g·min-1 to 1.98±0.75 g·min-1; P<0.05); NORM oxidation rates were unchanged (fat: 0.26±0.18 g·min-1 to 0.33±0.18 g·min-1; P=0.5; carbohydrate: 2.51±0.49 g·min-1 to 2.29±0.47 g·min-1; P=0.3).. Cycling at low-intensity 12 h post-downhill running with lowered muscle glycogen increased fat oxidation, decreased carbohydrate oxidation and elevated carbon dioxide ventilation. Damaging exercise with reduced glycogen availability increases fat utilization during subsequent low-intensity exercise as little as 12 h later.

Topics: Adult; Athletes; Athletic Injuries; Blood Glucose; Cardiorespiratory Fitness; Exercise; Fats; Glycogen; Humans; Male; Muscle, Skeletal; Oxygen Consumption; Running; Young Adult

Low muscle glycogen levels due to consecutive days of extensive exercise have been shown to cause fatigue and thus decrements in performance. Low muscle glycogen levels could also lead to oxidation of the branched chain amino acids and central fatigue. Therefore, the questions become, can low muscle glycogen not only lead to peripheral and central fatigue but also to overtraining, and if so can overtraining be avoided by consuming sufficient quantities of carbohydrates? Research on swimmers has shown that those who were nonresponsive to an increase in their training load had low levels of muscle glycogen and consumed insufficient energy and carbohydrates. However, cyclists who increased their training load for 2 wk but also increased carbohydrate intake to maintain muscle glycogen levels still met the criteria of over-reaching (short-term overtraining) and might have met the criteria for overtraining had the subjects been followed for a longer period of time. Thus, some other mechanism than reduced muscle glycogen levels must be responsible for the development and occurrence of overtraining.

Topics: Athletic Injuries; Bicycling; Dietary Carbohydrates; Energy Metabolism; Fatigue; Glycogen; Humans; Hydrocortisone; Lactic Acid; Male; Muscle, Skeletal; Physical Education and Training; Stress, Psychological; Syndrome

Topics: Athletic Injuries; Glycogen; Humans; Knee Injuries; Muscles; Physical Exertion; Skiing

Topics: Athletic Injuries; Dietary Carbohydrates; Glycogen; Humans; Muscles; Nutritional Requirements; Skiing

In the past three decades, wheelchair sports have become an international reality. Disabled athletes are exercising their right to accept the challenges and risks taken by able-bodied athletes. Marathon racing over a 26-mile, 385-yard course is the latest and most strenuous of the wheelchair athletic events. The small amount of available research data on wheelchair sports has been summarized, as well as some relevant data from exercise physiology studies on able-bodied subjects. Physicians and other health professionals who work with disabled people should be knowledgeable about the risks and benefits of wheelchair sports. Much more basic research is needed to improve the safety, training techniques, and performance of wheelchair athletes.

Topics: Athletic Injuries; Body Weight; Capillaries; Dehydration; Energy Metabolism; Female; Glycogen; Humans; Hypothermia; Male; Muscles; Oxygen Consumption; Paraplegia; Sports; Sports Medicine; Wheelchairs

Topics: Adult; Athletic Injuries; Braces; Endoscopy; Glycogen; Humans; Knee Injuries; Ligaments, Articular; Male; Methods; Muscles; Rupture; Skiing; Soccer