60 results on '"Israel RG"'
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2. Absolute fat mass, percent body fat, and body-fat distribution: which is the real determinant of blood pressure and serum glucose?
- Author
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Spiegelman, D, primary, Israel, RG, additional, Bouchard, C, additional, and Willett, WC, additional
- Published
- 1992
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3. Obesity drugs and drugs in the pipeline.
- Author
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Hickey MS and Israel RG
- Abstract
Learn more about a variety of investigational drugs which target appetite, metabolism, and the GI tract that are under investigation as potential obesity treatment options. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
4. American College of Sports Medicine Roundtable. The physiological and health effects of oral creatine supplementation.
- Author
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Terjung RL, Clarkson P, Eichner ER, Greenhaff PL, Hespel PJ, Israel RG, Kraemer WJ, Meyer RA, Spriet LL, Tarnopolsky MA, Wagenmakers AJM, and Williams MH
- Published
- 2000
5. A long-duration (118-day) backpacking trip (2669 km) normalizes lipids without medication: a case study.
- Author
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Devoe D, Israel RG, Lipsey T, and Voyles W
- Subjects
- Appalachian Region, Conservation of Natural Resources, Diet, Humans, Male, Middle Aged, Exercise, Hyperlipidemias, Lipids blood
- Abstract
Objective: To evaluate the effects of a long-distance backpacking trip on body composition, weight, blood lipids, and lipoproteins., Methods: Single-subject (male, aged 49 years) study of an experienced backpacker who hiked 118 days on the Appalachian Trail. Outcome measures that were assessed pre-hike and post-hike included body fat (%) by hydrostatic weighing and skinfold assessment, height and weight, body mass index (BMI), circumference measurements (umbilicus, anterior suprailiac, maximum hip, greater trochanter, minimum waist, umbilicus/anterior suprailiac ratio), and blood pressure (systolic and diastolic at rest and peak). Dietary analyses (total kilocalories, protein, carbohydrate, fat, cholesterol, saturated fat, monounsaturated fat, polyunsaturated fat, dietary fiber) were conducted pre-hike, on days 54 through 56, and on days 98 through 100. Blood lipids and lipoproteins (triglycerides, high-density lipoprotein, low-density lipoprotein) were measured pre-hike, on day 89, and post-hike., Results: Pre-post differences showed decreases in body weight, from 85.3 kg to 73.9 kg (-11.4 [-13.4%]); percent body fat, hydrostatic weighing, from 25.18 to 14.31 (-10.87 [-43.2%]); percent body fat, skinfolds (7-site), from 23.79 to 11.61 (12.18 [-51.2%]); and BMI, from 29.37 to 25.46 (-3.91 [-13.3%]). Pre-post differences in blood lipid changes over the course of 118 days were as follows: triglycerides (mg x dL(-1)) fell from 319 to 79 (-240 [-75%]); total cholesterol (mg x dL(-1)) fell from 276 to 196 (-80 [-29%]); high-density lipoprotein (HDL) (mg x dL(-1)) rose from 46 to 63 (+17 [+37%]); low-density lipoprotein (LDL) (mg.dL(-1)) fell from 167 to 118 (-49 [-29%]); LDL/HDL ratio fell from 3.63 to 1.87 (-1.76 [-48%]); and total cholesterol/HDL ratio fell from 6.00 to 3.11 (-2.89 [-48%])., Conclusion: The physical activity and diet associated with an extended backpacking adventure can considerably reduce and clinically normalize blood lipids and lipoproteins without medication and can very positively affect body composition and weight.
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- 2009
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6. Cardiorespiratory fitness and the metabolic syndrome in firefighters.
- Author
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Donovan R, Nelson T, Peel J, Lipsey T, Voyles W, and Israel RG
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- Adult, Colorado epidemiology, Death, Sudden, Cardiac prevention & control, Exercise Test, Humans, Male, Fires, Metabolic Syndrome epidemiology, Physical Fitness physiology, Rescue Work
- Abstract
Background: The leading cause of mortality in on-duty firefighters is sudden cardiac death. While the reason for this remains unclear, low cardiorespiratory fitness and the metabolic syndrome have been associated with increased risk of cardiovascular disease-related events., Aims: To document the levels of cardiorespiratory fitness and the metabolic syndrome, as well as to determine if there is a relationship between these variables, in firefighters., Methods: Maximal cardiorespiratory fitness was assessed using the Bruce treadmill protocol in 214 male firefighters from Colorado. As part of a comprehensive cardiovascular disease risk evaluation, each firefighter was also screened for the metabolic syndrome using the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) guidelines., Results: At the time of their evaluation, 32 firefighters (15%) met the NCEP/ATP III diagnostic criteria for the metabolic syndrome, and 54 firefighters (25%) failed to achieve a generally accepted minimum cardiorespiratory fitness level of 42.0 ml/kg/min. A significant inverse trend of increasing cardiorespiratory fitness with decreasing metabolic abnormalities was found (P < 0.001)., Conclusions: Increased levels of cardiorespiratory fitness are associated with an improved metabolic profile in male firefighters. Comprehensive cardiovascular disease risk factor management and cardiorespiratory fitness improvement are essential for firefighter health and safety.
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- 2009
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7. A family-based approach to preventing excessive weight gain.
- Author
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Rodearmel SJ, Wyatt HR, Barry MJ, Dong F, Pan D, Israel RG, Cho SS, McBurney MI, and Hill JO
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- Adiposity physiology, Adolescent, Adult, Analysis of Variance, Body Mass Index, Body Weight physiology, Child, Child Nutritional Physiological Phenomena, Energy Intake physiology, Family Health, Female, Humans, Male, Nutrition Assessment, Obesity physiopathology, Time Factors, Treatment Outcome, Diet, Fat-Restricted, Edible Grain, Obesity prevention & control, Weight Gain physiology
- Abstract
Objective: Preventing weight gain in adults and excessive weight gain in children is a high priority. We evaluated the ability of a family-based program aimed at increasing steps and cereal consumption (for breakfast and snacks) to reduce weight gain in children and adults., Research Methods and Procedures: Families (n = 105) with at least one 8- to 12-year-old child who was at-risk-for-overweight or overweight (designated as the target child) were recruited for the study. Eighty-two families were randomly assigned to receive the family-based intervention and 23 families to the control condition. The 13-week intervention consisted of specific increases in daily steps (an additional 2000 steps/d) and consumption of 2 servings/d of ready-to-eat cereal., Results: The intervention was successful in increasing walking (steps) and cereal consumption. The intervention had positive, significant effects on percentage BMI-for-age and percentage body fat for target children and weight, BMI, and percentage body fat for parents. On further analysis, the positive effects of the intervention were seen largely in target girls and moms, rather than in target boys and dads., Discussion: This family-based weight gain prevention program based on small changes holds promise for reducing excessive weight gain in families and especially in growing overweight children.
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- 2006
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8. Influence of moderate chronic wine consumption on insulin sensitivity and other correlates of syndrome X in moderately obese women.
- Author
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Cordain L, Melby CL, Hamamoto AE, O'Neill DS, Cornier MA, Barakat HA, Israel RG, and Hill JO
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- Adult, Blood Glucose analysis, Energy Intake, Female, Humans, Insulin blood, Lipids blood, Middle Aged, Alcohol Drinking, Insulin Resistance, Microvascular Angina physiopathology, Obesity physiopathology, Wine
- Abstract
Epidemiologic studies indicate that alcohol consumption is associated with improved insulin sensitivity; however, scant experimental evidence confirms this observation. To determine the effects of regular moderate wine consumption on insulin sensitivity, 20 overweight women (body mass index [BMI], 29.8 +/- 2.2 kg/m2) participated in a 20-week free-living randomized crossover trial. The subjects, serving as their own controls, consumed wine (190 mL red wine, 13% vol/vol ethanol, 5 days per week) for 10 weeks and abstained for 10 weeks or vice versa. The dependent variables (body weight, BMI, percent body fat, blood pressure, fasting blood glucose and insulin, blood lipids, dietary intake, and insulin sensitivity by intravenous glucose tolerance test [IVGTT]) were measured at the pretest, at the 10-week crossover, and at the 20-week completion of the study. Data were analyzed at the pretest and at completion of the wine drinking and abstention periods of the study using ANOVA by order of treatment. Fasting glucose remained unchanged (mean +/- SD; P > .05) throughout the experiment (pretest, drinking, and abstention, 91.1 +/- 9.2, 91.6 +/- 9.1, and 88.5 +/- 11.2 mg/dL), as did the measures of insulin sensitivity, fasting insulin (pretest, drinking, and abstention, 8.6 +/- 3.3, 8.6 +/- 4.1, and 9.1 +/- 4.7 microU/mg) and the insulin sensitivity index (3.60 +/- 2.96, 3.25 +/- 2.17, and 3.30 +/- 1.84). Body composition and blood lipids also remained unchanged (P > .05) during treatment. Moderate wine consumption at this dose in overweight women did not improve or impair insulin sensitivity, nor did it change any of the known correlates of insulin sensitivity, including body weight and composition, blood lipids, and blood pressure.
- Published
- 2000
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9. Effects of oral combined hormone replacement therapy on plasma lipids and lipoproteins.
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Vadlamudi S, MacLean P, Israel RG, Marks RH, Hickey M, Otvos J, and Barakat H
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- Administration, Oral, Cardiovascular Diseases etiology, Cross-Sectional Studies, Female, Humans, Middle Aged, Risk Factors, Estrogen Replacement Therapy, Lipids blood, Lipoproteins blood
- Abstract
Hormone replacement therapy has been shown to decrease the risk of coronary heart disease (CHD) in menopausal women. In this cross-sectional study, we addressed the following question: What effects would combined oral hormone replacement therapy have on plasma lipid and lipoprotein profiles independent of the other known CHD risk factors? We analyzed the plasma lipoproteins of two groups of menopausal women who were randomly selected from a large database of individuals. One group (n = 10) was not taking any hormone replacement therapy (NO HRT), while the second group (n = 8) was taking a daily dose of 0.625 mg conjugated estrogen and 2.5 mg medroxyprogesterone orally (PremPro, Wyeth-Ayerst, Philadelphia, PA) for at least 6 months (HRT). The two groups were not different in age, body weight, percent body fat, body mass index (BMI), waist to hip ratio, blood pressure, or insulin and glucose levels. High-density lipoprotein (HDL)-cholesterol was significantly higher (P < .05) in the HRT group. The total cholesterol (TC) to HDL-cholesterol ratio was significantly lower for HRT versus NO HRT (P < .05). Apolipoprotein (apo) A-1, the apo A-1/B ratio, and lecithin:cholesterol acyltransferase (LCAT) activity were significantly higher in HRT (P < .05). Lipoprotein subclass profiles measured by nuclear magnetic resonance (NMR) spectroscopy showed an increase in larger HDL subpopulations (H3 and H4) in HRT (P < .05), which are considered antiatherogenic. No differences were seen in the cholesterol concentration or size of low-density lipoprotein (LDL) subpopulations in HRT compared with NO HRT. These results indicate that the combined estrogen and progesterone treatment leads to beneficial effects on plasma lipoproteins. The beneficial effects include (1) increases in HDL-cholesterol and predominance of HDL2, (2) no adverse effects on LDL subpopulation distribution, and (3) increases in apo A-1 levels and LCAT activity, which indicate an improvement in reverse cholesterol transport.
- Published
- 1998
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10. Differential white cell count after two bouts of downhill running.
- Author
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Smith LL, Bond JA, Holbert D, Houmard JA, Israel RG, McCammon MR, and Smith SS
- Subjects
- Adult, Analysis of Variance, Circadian Rhythm, Creatine Kinase blood, Follow-Up Studies, Humans, Hydrocortisone blood, Lymphocyte Count, Male, Monocytes cytology, Muscle Contraction physiology, Muscle, Skeletal pathology, Muscle, Skeletal physiology, Neutrophils cytology, Oxygen Consumption physiology, Pain physiopathology, Plasma Volume, Time Factors, Leukocyte Count, Running physiology
- Abstract
The purpose of this study was to compare blood markers associated with eccentrically biased exercise and muscle damage, after two bouts of downhill running. Nine active, untrained males performed 2 x 45 min bouts of downhill running (-0.16 radians), at a speed that would elicit 70% of each subjects VO2max, on a level grade; runs were spaced 14d apart (RUN1, RUN2). Blood samples were obtained before, after, and every hour for 12 h after exercise, as well as every 24 h for 5 d, to assess numbers of circulating neutrophils, monocytes, and lymphocytes, serum cortisol, creatine kinase (CK); subjective sensations of delayed onset muscle soreness (DOMS) were monitored. To control for diurnal variation, two weeks prior to the RUN1, subjects had blood draws performed at the same time as would occur after exercise, but did no exercise (CONTROL). During the 5 d after exercise, DOMS and CK were significantly greater (p < 0.05) after RUN1 compared to RUN2 and CONTROL. During the 12 h after RUN1 and RUN2, neutrophils showed similar responses compared to CONTROL. However, neutrophils were significantly elevated at 96 h after RUN1 and 24 h after RUN2. Monocytes were significantly elevated during 5-11 h after RUN1 and RUN2, compared to CONTROL. Cortisol showed a similar significant diurnal decrease for all three conditions during the 12 h following exercise. The significantly lower levels of CK and DOMS seen after RUN2, compared with the initial run is consistent with the literature. The similar changes in neutrophils and monocytes during the 12 h following RUN1 and RUN2, followed by disparate responses over the subsequent 5 d, requires further investigation.
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- 1998
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11. A new paradigm for type 2 diabetes mellitus: could it be a disease of the foregut?
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Hickey MS, Pories WJ, MacDonald KG Jr, Cory KA, Dohm GL, Swanson MS, Israel RG, Barakat HA, Considine RV, Caro JF, and Houmard JA
- Subjects
- Adult, Blood Glucose analysis, Body Weight, Diabetes Mellitus, Type 2 complications, Female, Glycated Hemoglobin analysis, Humans, Insulin blood, Leptin, Obesity, Morbid complications, Obesity, Morbid surgery, Proteins analysis, Diabetes Mellitus, Type 2 physiopathology, Diabetes Mellitus, Type 2 prevention & control, Gastric Bypass
- Abstract
Summary Background Data: We previously reported, in a study of 608 patients, that the gastric bypass operation (GB) controls type 2 diabetes mellitus in the morbidly obese patient more effectively than any medical therapy. Further, we showed for the first time that it was possible to reduce the mortality from diabetes; GB reduced the chance of dying from 4.5% per year to 1% per year. This control of diabetes has been ascribed to the weight loss induced by the operation. These studies, in weight-stable women, were designed to determine whether weight loss was really the important factor., Methods: Fasting plasma insulin, fasting plasma glucose, minimal model-derived insulin sensitivity and leptin levels were measured in carefully matched cohorts: six women who had undergone GB and had been stable at their lowered weight 24 to 30 months after surgery versus a control group of six women who did not undergo surgery and were similarly weight-stable. The two groups were matched in age, percentage of fat, body mass index, waist circumference, and aerobic capacity., Results: Even though the two groups of patients were closely matched in weight, age, percentage of fat, and even aerobic capacity, and with both groups maintaining stable weights, the surgical group demonstrated significantly lower levels of serum leptin, fasting plasma insulin, and fasting plasma glucose compared to the control group. Similarly, minimal model-derived insulin sensitivity was significantly higher in the surgical group. Finally, self-reported food intake was significantly lower in the surgical group., Conclusions: Weight loss is not the reason why GB controls diabetes mellitus. Instead, bypassing the foregut and reducing food intake produce the profound long-term alterations in glucose metabolism and insulin action. These findings suggest that our current paradigms of type 2 diabetes mellitus deserve review. The critical lesion may lie in abnormal signals from the gut.
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- 1998
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12. Gender-dependent effects of exercise training on serum leptin levels in humans.
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Hickey MS, Houmard JA, Considine RV, Tyndall GL, Midgette JB, Gavigan KE, Weidner ML, McCammon MR, Israel RG, and Caro JF
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- Adult, Anthropometry, Energy Intake, Exercise, Female, Humans, Insulin blood, Leptin, Male, Middle Aged, Obesity blood, Osmolar Concentration, Oxygen Consumption, Physical Education and Training, Proteins analysis, Sex Characteristics
- Abstract
Leptin, the product of the ob gene, is elevated in obese humans and appears to be closely related to body fat content. The purpose of the present investigation was to determine the effect of aerobic exercise training on systemic leptin levels in humans. Eighteen sedentary middle-aged men (n = 9) and women (n = 9) who did not differ in aerobic capacity (29.4 +/- 1.2 vs. 27.5 +/- 1.2 ml x kg(-1) x min(-1)) or insulin sensitivity index (3.41 +/- 1.12 vs. 4.88 +/- 0.55) were studied. Fat mass was significantly lower in females vs. males (21.83 +/- 2.25 vs. 26.99 +/- 2.37 kg, P < 0.05). Despite this, fasting serum leptin was significantly higher in the females vs. males (18.27 +/- 2.55 vs. 9.88 +/- 1.26 ng/ml, P < 0.05). Serum leptin concentration decreased 17.5% in females (P < 0.05) after 12 wk of aerobic exercise training (4 day/wk, 30-45 min/day) but was not significantly reduced in males. Fat mass was not altered after training in either group. In contrast, both aerobic capacity (+13% males, +9.1% females) and insulin sensitivity (+35% males, +82% females) were significantly improved subsequent to training. These data suggest that 1) women have higher circulating leptin concentrations despite lower fat mass and 2) exercise training appears to have a greater effect on systemic leptin levels in females than in males.
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- 1997
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13. Leptin is related to body fat content in male distance runners.
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Hickey MS, Considine RV, Israel RG, Mahar TL, McCammon MR, Tyndall GL, Houmard JA, and Caro JF
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- Adipose Tissue physiology, Adult, Body Mass Index, Exercise Test, Fasting, Humans, Leptin, Male, Middle Aged, Obesity, Oxygen Consumption, Physical Exertion, Proteins analysis, Adipose Tissue anatomy & histology, Proteins metabolism, Running
- Abstract
Leptin, the product of the ob gene, has been reported to be related to body fat in humans (Considine et al. N. Engl. J. Med. 334: 292, 1996). However, little is known about the physiology of this putative satiety signal in humans. The purpose of the present study was to determine whether leptin is related to body fat content in relatively lean endurance-trained adults. In addition, the effect of acute exercise on circulating leptin concentration was studied. Thirteen male runners, whose mean age, height, weight, %fat, and maximal oxygen consumption (VO2max) were 32.2 +/- 2.5 yr, 176.2 +/- 1.6 cm, 71.9 +/- 6.9 kg, 9.7 +/- 0.9%, and 62.9 +/- 2.2 ml.kg-1.min-1, respectively, were studied. Blood samples were obtained after an overnight fast and again immediately after the completion of a 20-mile run at 70% VO2max under controlled environmental conditions. Serum leptin was closely related to fat mass (r = 0.92) in the runners. Acute exercise had no detectable effect on serum leptin levels (PRE = 2.19 +/- 0.32 ng/ml, POST = 2.14 +/- 0.36 ng/ml). These data indicate that, even at a biological extreme of body fat, circulating leptin concentration is closely related to fat content. Furthermore, the data suggest that, in trained individuals with low leptin concentrations, acute exhaustive exercise has no immediate effect on circulating leptin concentration.
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- 1996
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14. Gender differences in serum leptin levels in humans.
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Hickey MS, Israel RG, Gardiner SN, Considine RV, McCammon MR, Tyndall GL, Houmard JA, Marks RH, and Caro JF
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- Adult, Aged, Body Weight, Cholesterol, HDL blood, Cholesterol, LDL blood, Fasting, Female, Humans, Insulin blood, Leptin, Male, Middle Aged, Proteins analysis, Sex Characteristics
- Abstract
Leptin, the product of the ob gene, is an adipose tissue-derived hormone that appears to regulate both satiety and thermogenesis. In the present report, we have reexamined the relationship between circulating leptin concentration and body fat in humans using a more valid measure of adiposity (hydrodensitometry) and have extended these observations to examine the influence of regional body fat distribution and cardiorespiratory fitness. Fasting serum leptin concentration was 6.9 +/- 0.3 ng.ml-1 in males (N = 333) and 15.2 +/- 1.3 ng.ml-1 in females (N = 63). Interestingly, total fat mass did not differ between groups (males 20.5 +/- 0.5 kg; females 20.4 +/- 1.5 kg), suggesting that females have higher leptin levels per unit fat mass. In a multiple regression model, fat mass was the best predictor of serum leptin concentration in males, accounting for 51% of the variance in leptin concentration. In females, percentage body fat was the best predictor of leptin, accounting for 49% of the variance. In both groups, the relationship between leptin and adiposity remained significant after adjusting for age, maximal treadmill time, waist circumference, and fasting insulin concentration. These observations support previous conclusions that circulating leptin is primarily a function of adiposity and demonstrate for the first time that this relationship is independent of fat distribution or cardiorespiratory fitness. The data also suggest that there is a gender dichotomy in the relationship between leptin and body fat mass in humans.
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- 1996
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15. Adaptive responses to muscle lengthening and shortening in humans.
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Hortobágyi T, Hill JP, Houmard JA, Fraser DD, Lambert NJ, and Israel RG
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- Adult, Electromyography, Humans, Male, Time Factors, Exercise physiology, Knee physiology, Muscle Fatigue physiology, Muscle Fibers, Skeletal physiology
- Abstract
We tested the hypothesis that exercise training with maximal eccentric (lengthening) muscle actions results in greater gains in muscle strength and size than training with concentric (shortening) actions. Changes in muscle strength, muscle fiber size, and surface electromyographic (EMG) activity of the quadriceps muscle were compared after 36 sessions of isokinetic concentric (n = 8) or eccentric (n = 7) exercise training over 12 wk with use of a one-leg model. Eccentric training increased eccentric strength 3.5 times more (pre/post 46%, P < 0.05) than concentric training increased concentric strength (pre/post 13%). Eccentric training increased concentric strength and concentric training increased eccentric strength by about the same magnitude (5 and 10%, respectively, P > 0.05). Eccentric training increased EMG activity seven times more during eccentric testing (pre/post 86%, P < 0.05) than concentric training increased EMG activity during concentric testing (pre/post 12%). Eccentric training increased the EMG activity measured during concentric tests and concentric training increased the EMG activity measured during eccentric tests by about the same magnitude (8 and 11%, respectively, P > 0.05). Type I muscle fiber percentages did not change significantly, but type IIa fibers increased and type IIb fibers decreased significantly (P < 0.05) in both training groups. Type I fiber areas did not change significantly (P > 0.05), but type II fiber area increased approximately 10 times more (P < 0.05) in the eccentric than in the concentric group. It is concluded that adaptations to training with maximal eccentric contractions are specific to eccentric muscle actions that are associated with greater neural adaptation and muscle hypertrophy than concentric exercise.
- Published
- 1996
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16. Skeletal muscle fiber composition is related to adiposity and in vitro glucose transport rate in humans.
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Hickey MS, Carey JO, Azevedo JL, Houmard JA, Pories WJ, Israel RG, and Dohm GL
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- Biological Transport drug effects, Body Mass Index, Diabetes Mellitus metabolism, Diabetes Mellitus pathology, Diabetes Mellitus, Type 2 metabolism, Diabetes Mellitus, Type 2 pathology, Humans, In Vitro Techniques, Insulin pharmacology, Kinetics, Muscle, Skeletal metabolism, Obesity metabolism, Obesity pathology, Adipose Tissue, Body Composition, Glucose metabolism, Muscle, Skeletal pathology
- Abstract
The purpose of this study was to determine if a relationship exists among skeletal muscle fiber composition, adiposity, and in vitro muscle glucose transport rate in humans. Rectus abdominus muscle was obtained during elective abdominal surgery from nonobese control (n = 12), obese (n = 12), and obese non-insulin-dependent diabetes mellitus (NIDDM) patients (n = 10). The obese NIDDM group had a significantly lower percentage of type I muscle fibers (32.2 +/- 1.9%) than the obese group (40.4 +/- 2.7%), and both obese groups were significantly lower than the control group (50.0 +/- 2.6%). Insulin-stimulated glucose transport, determined on 28 subjects, was significantly lower in both the obese (3.83 +/- 0.48 nmol.min-1.mg-1) and NIDDM (3.93 +/- 1.0 nmol.min-1.mg-1) groups vs. the control group (7.35 +/- 1.50 nmol.min-1.mg-1). Body mass index (BMI) was inversely correlated to percent type I fibers (r = -0.50, P < 0.01) and to the insulin-stimulated glucose transport rate (r = -0.53, P < 0.01). The percentage of type I muscle fibers was related to the insulin-stimulated glucose transport rate (r = 0.57, P < 0.01), although this relationship was not significant after adjusting for BMI. Although these data do not support an independent relationship between fiber type and insulin action in obesity, a reduced skeletal muscle type I fiber population may be one component of a multifactorial process involved in the development of insulin resistance.
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- 1995
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17. The impact of a repeated bout of eccentric exercise on muscular strength, muscle soreness and creatine kinase.
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Smith LL, Fulmer MG, Holbert D, McCammon MR, Houmard JA, Frazer DD, Nsien E, and Israel RG
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- Adult, Analysis of Variance, Cholesterol blood, Humans, Male, Muscle, Skeletal enzymology, Time Factors, Creatine Kinase blood, Muscle Contraction physiology, Muscle, Skeletal physiology, Pain physiopathology, Weight Lifting physiology
- Abstract
The purpose of this study was to determine if there were any beneficial or detrimental effects regarding delayed onset muscle soreness (DOMS), serum creatine kinase (CK), and maximum concentric strength at 80% of 1-RMconc, if a bout of eccentric exercise was repeated at 48 h after an initial bout. A secondary purpose was to determine whether unaccustomed eccentrics might affect plasma cholesterol (TC). Twenty-six men were randomly assigned to a control (Group 1) or experimental group (Group 2). Both groups performed three sets (12 repetitions per set) of the eccentric phase of a chest press, at 80% of one repetition maximum (1-RMconc); Group 2 repeated this exercise 48 h later. DOMS and CK were measured before, and every 24 h for 8 days after; TC was measured before, and every 24 h for 4 days. Maximum strength during the concentric phase of a chest press (1-RMconc) was measured before and at 48-h intervals after. A repeated measures analysis of variance revealed a significant time effect (P < 0.05) for DOMS, CK and strength, but no significant difference between groups (P < 0.05). An interesting finding was the significant (P < 0.05) reduction in TC at 24, 48 and 72 h, after exercise in both groups, which we hypothesized was associated with cellular repair. From these results we concluded that when a bout of eccentrics is repeated 48 h after an initial bout, there is no change in the characteristic time-course and/or intensity of DOMS, CK or 1-RMconc.
- Published
- 1994
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18. Sensitivity and specificity of the Quetelet index to assess obesity in men and women.
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Hortobágyi T, Israel RG, and O'Brien KF
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- Adult, Aged, Anthropometry, Body Composition, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Reference Values, Body Mass Index, Obesity classification
- Abstract
Objective and Methods: In a cross-sectional design, the sensitivity and specificity of the Quetelet Index (QI) was determined in relation to percent body fat standards. Subjects were 1280 men and 365 women asymptomatic for coronary heart disease. Contingency tables by QI quartiles were created using two sets of criteria of obesity: body fat > or = 25% and QI > or = 28 kg.m-2 for men and 30% and 27 kg.m-2 for women. Percent body fat was determined with hydrodensitometry in all subjects., Results: In men, sensitivity, positive, and negative predictive value of QI in relation to percent body fat was 54.5%, 91.8%, 82.7% and 73.8%, respectively. The corresponding values for women were 26.9%, 98.2%, 90.7% and 67.1%. Sensitivity of QI was 2.03 times greater for men than for women (P < 0.001). Receiver operator characteristic (ROC) curve analysis suggested that an acceptable trade-off between sensitivity (91%) and specificity (47%) occurred at a QI of 24.5 kg.m-2 for men and at a QI of 22 kg.m-2 for women., Conclusions: The data suggest that in an asymptomatic population, percent body fat-based QI cut-off values may misclassify the obese. A fat mass-based reference system could perhaps lead to an improved classification outcome.
- Published
- 1994
19. Effects of exercise training on absolute and relative measurements of regional adiposity.
- Author
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Houmard JA, McCulley C, Roy LK, Bruner RK, McCammon MR, and Israel RG
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- Adult, Aged, Anthropometry, Cholesterol blood, Cholesterol, HDL blood, Diet, Humans, Insulin pharmacology, Lipoproteins, HDL blood, Male, Middle Aged, Physical Endurance, Skinfold Thickness, Triglycerides blood, Adipose Tissue, Body Composition, Exercise
- Abstract
The purpose of the present study was to determine whether absolute and relative measurements of regional adiposity differ in their responses to exercise intervention and which measures are most predictive of changes in plasma lipids, insulin sensitivity and adiposity. Thirteen middle-aged men (BMI 30.4 +/- 1.5 kg/m2, age 47.2 +/- 1.5 years, mean +/- s.e.) were examined before and after 14 weeks of endurance-oriented physical activity (3-4 days/week, 30-45 min/day). Significant (P < 0.05) decreases in the absolute measures of chest, waist and hip girths and sagittal diameter were evident. The waist-to-hip ratios (WHR) of umbilicus/maximal hip and minimal waist/maximal hip decreased significantly (P < 0.05). However, the WHRs of umbilicus/anterior superior iliac spine and umbilicus/greater trochanters did not change due to parallel decreases in waist and hip girths. Trunk and extremity skinfolds decreased significantly (P < 0.05); however, trunk/extremity skinfold ratios were virtually unaltered. The training programme significantly (P < 0.05) increased insulin sensitivity (60%) and HDL (8%), and reduced triglyceride (25%) and total cholesterol/HDL (8%). Changes in these variables were related to changes in sagittal diameter and waist girth. These data indicate different responses to physical activity between measurements of regional adiposity, and emphasize the need for considering absolute central girths such as waist circumference and sagittal diameter when assessing fat topography and cardiovascular risk.
- Published
- 1994
20. Relationship between cardiorespiratory fitness and lipoprotein(a) in men and women.
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Israel RG, Sullivan MJ, Marks RH, Cayton RS, and Chenier TC
- Subjects
- Adipose Tissue anatomy & histology, Adult, Blood Glucose analysis, Blood Pressure physiology, Body Composition, Body Mass Index, Cholesterol blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Coronary Disease etiology, Coronary Disease genetics, Cross-Sectional Studies, Electrocardiography, Exercise Test, Female, Heart Rate physiology, Humans, Male, Middle Aged, Risk Factors, Triglycerides blood, Lipoprotein(a) blood, Physical Fitness physiology
- Abstract
Lipoprotein(a) [Lp(a)] is a distinct lipoprotein of the low density lipoprotein (LDL) class. Research has shown that elevated Lp(a) is an independent risk factor for coronary heart disease (CHD). The purpose of this cross-sectional study was to determine whether fitness was associated with Lp(a) concentrations. Cardiorespiratory (CR) fitness, assessed by maximal treadmill time, percent body fat (hydrodensitometry), body fat distribution (waist/hip ratio), lipoprotein profile and LDL particle size (2-16% gel electrophoresis) were determined in healthy Caucasian men (N = 100) and women (N = 50). As expected, the frequency distribution of Lp(a) was highly skewed with a mean level of 16.9 +/- 19.1 mg.dl-1 (range 0.10-90 mg.dl-1) for men and women combined. Lp(a) was only significantly (P < 0.05) correlated with cholesterol (r = 0.29) in women and LDL-C (r = 0.22) in men. However, after correcting LDL-C for Lp(a) content, the correlation was not significant (r = 0.06). A MANCOVA, controlling for age, across highest and lowest CR fitness quartiles suggest a typical positive influence of improved CR fitness on lipoproteins, body composition, and fat distribution; however, Lp(a) levels were not affected. These data indicate that there is no direct association between plasma Lp(a) and body composition, fat distribution, or CR fitness in healthy men and women.
- Published
- 1994
21. Effects of exercise training on the chemical composition of plasma LDL.
- Author
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Houmard JA, Bruno NJ, Bruner RK, McCammon MR, Israel RG, and Barakat HA
- Subjects
- Adult, Aged, Blood Glucose analysis, Body Composition, Coronary Disease etiology, Humans, Lipids blood, Lipoproteins, LDL blood, Male, Middle Aged, Oxygen Consumption, Exercise, Lipoproteins, LDL analysis
- Abstract
The purpose of the present study was to determine the effects of exercise training on the chemical composition of plasma low-density lipoprotein (LDL). Thirteen men (mean age +/- SE, 47.2 +/- 1.5 years) were examined before and after 14 weeks of endurance-oriented exercise training (3 to 4 d/wk, 30 to 45 min/d). Although calculated plasma LDL concentrations remained unaltered (3.49 +/- 0.24 versus 3.65 +/- 0.23 mmol/L), changes in the chemical composition of LDL (increased LDL free cholesterol, cholesterol ester, and phospholipid content) were associated with a reduction in adiposity, umbilical girth, and basal plasma insulin and glucose concentration with training intervention. Increases in LDL molecular weight and particle diameter were associated with a reduction in fat mass, plasma triglyceride concentration, and basal plasma glucose concentration with physical activity. The LDL lipid-to-protein ratio also increased (P < .01) with training by 7%, primarily due to an increase in LDL free cholesterol content (P < .01). These findings indicate the formation of LDL particles that are more cholesterol enriched and protein poor with exercise training, which provides additional evidence for the cardioprotective effect of long-term physical activity.
- Published
- 1994
- Full Text
- View/download PDF
22. The effects of athletic massage on delayed onset muscle soreness, creatine kinase, and neutrophil count: a preliminary report.
- Author
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Smith LL, Keating MN, Holbert D, Spratt DJ, McCammon MR, Smith SS, and Israel RG
- Subjects
- Adult, Humans, Hydrocortisone blood, Leukocyte Count, Male, Myositis physiopathology, Creatine Kinase blood, Exercise physiology, Isometric Contraction physiology, Massage, Neutrophils immunology, Pain Measurement
- Abstract
It was hypothesized that athletic massage administered 2 hours after eccentric exercise would disrupt an initial crucial event in acute inflammation, the accumulation of neutrophils. This would result in a diminished inflammatory response and a concomitant reduction in delayed onset muscle soreness (DOMS) and serum creatine kinase (CK). Untrained males were randomly assigned to a massage (N = 7) or control (N = 7) group. All performed five sets of isokinetic eccentric exercise of the elbow flexors and extensors. Two hours after exercise, massage subjects received a 30-minute athletic massage; control subjects rested. Delayed onset muscle soreness and CK were assessed before exercise and at 8, 24, 48, 72, 96, and 120 hours after exercise. Circulating neutrophils were assessed before and immediately after exercise, and at 30-minute intervals for 8 hours; cortisol was assessed before and immediately after exercise, and at 30-minute intervals for 8 hours; cortisol was assessed at similar times. A trend analysis revealed a significant (p < 0.05) treatment by time interaction effect for 1) DOMS, with the massage group reporting reduced levels; 2) CK, with the massage group displaying reduced levels; 3) neutrophils, with the massage group displaying a prolonged elevation; and 4) cortisol, with the massage group showing a diminished diurnal reduction. The results of this study suggest that sports massage will reduce DOMS and CK when administered 2 hours after the termination of eccentric exercise. This may be due to a reduced emigration of neutrophils and/or higher levels of serum cortisol.
- Published
- 1994
- Full Text
- View/download PDF
23. The effects of detraining on power athletes.
- Author
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Hortobágyi T, Houmard JA, Stevenson JR, Fraser DD, Johns RA, and Israel RG
- Subjects
- Adult, Body Height, Body Mass Index, Creatine Kinase blood, Electromyography, Football physiology, Growth Hormone blood, Hormones blood, Humans, Hydrocortisone blood, Isometric Contraction physiology, Knee Joint physiology, Male, Muscle Contraction physiology, Muscles anatomy & histology, Muscles innervation, Myofibrils ultrastructure, Neuromuscular Junction physiology, Testosterone blood, Weight Lifting physiology, Exercise physiology, Muscles physiology, Sports physiology
- Abstract
We investigated the effects of 14 d of resistive exercise detraining on 12 power athletes. In comparing performances pre- to post-detraining, there were no significant (P > 0.05) changes in free weight bench press (-1.7%), parallel squat (-0.9%), isometric (-7%) and isokinetic concentric knee extension force (-2.3%), and vertical jumping (1.2%). In contrast, isokinetic eccentric knee extension force decreased in every subject (-12%, P < 0.05). Post-detraining, the changes in surface EMG activity of the vastus lateralis during isometric, and isokinetic eccentric and concentric knee extension were -8.4%, -10.1%, and -12.7%, respectively (all P > 0.05). No significant changes occurred in knee flexion forces or EMGs (P > 0.05). Percentages of muscle fiber types and the Type I fiber area remained unchanged, but Type II fiber area decreased significantly by -6.4% (P < 0.05). Levels of plasma growth hormone (58.3%), testosterone (19.2%), and the testosterone to cortisol ratio (67.6%) increased, whereas plasma cortisol (-21.5%) and creatine kinase enzyme levels (-82.3%) decreased (all P < 0.05). Short-term resistive exercise detraining may thus specifically affect eccentric strength or the size of the Type II muscle fibers, leaving other aspects of neuromuscular performance uninfluenced. Changes in the hormonal milieu during detraining may be conducive to an enhanced anabolic process, but such changes may not materialize at the tissue level in the absence of the overload training stimulus.
- Published
- 1993
24. Increases in plasma prostaglandin E2 after eccentric exercise. A preliminary report.
- Author
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Smith LL, Wells JM, Houmard JA, Smith ST, Israel RG, Chenier TC, and Pennington SN
- Subjects
- Adult, Creatine Kinase blood, Female, Humans, Male, Muscular Diseases blood, Dinoprostone blood, Exercise physiology
- Published
- 1993
- Full Text
- View/download PDF
25. Exercise training increases GLUT-4 protein concentration in previously sedentary middle-aged men.
- Author
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Houmard JA, Shinebarger MH, Dolan PL, Leggett-Frazier N, Bruner RK, McCammon MR, Israel RG, and Dohm GL
- Subjects
- Body Composition, Energy Intake, Glucose Transporter Type 4, Humans, Insulin pharmacology, Male, Middle Aged, Muscles metabolism, Osmolar Concentration, Physical Endurance, Monosaccharide Transport Proteins metabolism, Muscle Proteins, Physical Education and Training
- Abstract
The purpose of this study was to determine if 14 wk of exercise training would increase insulin-sensitive glucose transporter protein (GLUT-4) concentration in skeletal muscle of previously sedentary middle-aged men (47.2 +/- 1.3 yr; n = 13). Muscle samples (lateral gastrocnemius) and insulin action [insulin sensitivity index (ISI), minimal model] were obtained in the sedentary condition and 48 h after the final training bout. GLUT-4 protein concentration increased (P < 0.001, 2,629 +/- 331 to 4,140 +/- 391 absorbance units/100 micrograms protein) with exercise training by 1.8-fold. ISI increased by twofold (P < 0.05, 2.1 +/- 0.5 to 3.4 +/- 0.7 SI x 10(5) min/pM) with training. The percentage of GLUT-4 rich type IIa muscle fibers increased by approximately 10% (P < 0.01), which may have contributed to the elevation in transporter protein. GLUT-4 concentration and citrate synthase activity (1.7-fold, P < 0.001) also increased by similar increments. These findings indicate that GLUT-4 protein concentration is elevated in middle-aged individuals with exercise training.
- Published
- 1993
- Full Text
- View/download PDF
26. Comparison of four methods to assess body composition in women.
- Author
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Eaton AW, Israel RG, O'Brien KF, Hortobagyi T, and McCammon MR
- Subjects
- Adult, Analysis of Variance, Bias, Evaluation Studies as Topic, Female, Humans, Hydrostatic Pressure, Linear Models, Middle Aged, Reproducibility of Results, Adipose Tissue, Body Composition, Body Weight, Plethysmography, Whole Body, Skinfold Thickness, Spectrophotometry, Infrared
- Abstract
The purpose of this study was to compare the accuracy of four methods to assess body composition of women. Seventy-seven Caucasian women [mean (+/- SD) age: 31.8 +/- 8.6 years; mass: 59.5 +/- 9.1 kg; stature: 162.4 +/- 6.9 cm; Quetelet Index: 22.5 +/- 3.1 kg/m2] were tested for percent body fat (%BF) with hydrostatic weighing (HW), near-infrared spectrophotometry (NIR), bioelectrical impedance analysis (BIA), and seven-site skinfolds (7-SFs). Compared to %BF with HW (24.9 +/- 6.5%), an analysis of variance revealed no mean differences (P > or = 0.05) among %BF with NIR (26.0 +/- 5.5%), BIA (25.7 +/- 5.8%) and 7-SFs (24.0 +/- 6.0%). The correlations between %BF with HW and NIR, BIA and 7-SF were r = 0.47, r = 0.77, and r = 0.79, respectively (P < or = 0.05), and prediction errors (SEE) were 5.8%, 4.2%, and 4.1%. Comparisons of %BF obtained from machine readings versus those computed from the manufacturer's equation indicated significant differences for the BIA (machine 25.7%, equation 27.8%) and NIR (machine 26.0%, equation 21.5%) methods. We concluded that although the mean %BF differences were small among the four methods, the large SEE values may allow the use of BIA and 7-SFs but not NIR. Inaccuracies of machine readings versus equation-computed %BF indicate that BIA and NIR variables and/or constants in the equations supplied are not identical to those used in machine-generated calculations.
- Published
- 1993
27. The effects of static and ballistic stretching on delayed onset muscle soreness and creatine kinase.
- Author
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Smith LL, Brunetz MH, Chenier TC, McCammon MR, Houmard JA, Franklin ME, and Israel RG
- Subjects
- Adult, Creatine Kinase blood, Humans, Male, Pain, Exercise physiology, Muscles physiology
- Abstract
The purpose of this study was to determine if static and ballistic stretching would induce significant amounts of delayed onset muscle soreness (DOMS) and increases in creatine kinase (CK). Twenty males were randomly assigned to a static (STATIC) or ballistic stretching (BALLISTIC) group. All performed three sets of 17 stretches during a 90-min period, the only group difference being that STATIC remained stationary during each 60-s stretch while BALLISTIC performed bouncing movements. Subjective ratings of DOMS (scale: 1-10) and serum CK levels were assessed before and every 24 hours post stretching, for 5 days. A repeated measures ANOVA revealed a significant main effect due to time (p < 0.05), with peak soreness occurring at 24 hours after (M = 2.8 +/- 1.6). Surprisingly, a group effect (p < .05) demonstrated that DOMS was significantly greater for STATIC than for BALLISTIC. At 24 hours there was a 62% (p < .05) increase in CK for combined groups. These findings indicate that similar bouts of static and ballistic stretching induce significant increases in DOMS and CK in subjects unaccustomed to such exercise. Furthermore, static stretching induced significantly more DOMS than did ballistic.
- Published
- 1993
- Full Text
- View/download PDF
28. Training cessation does not alter GLUT-4 protein levels in human skeletal muscle.
- Author
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Houmard JA, Hortobágyi T, Neufer PD, Johns RA, Fraser DD, Israel RG, and Dohm GL
- Subjects
- Adult, Body Composition, Citrate (si)-Synthase metabolism, Female, Glucose Tolerance Test, Glucose Transporter Type 4, Humans, Insulin blood, Insulin pharmacology, Male, Muscles anatomy & histology, Muscles chemistry, Physical Endurance, Physical Exertion, Physical Fitness, Running, Weight Lifting, Monosaccharide Transport Proteins metabolism, Muscle Proteins, Muscles metabolism, Physical Education and Training
- Abstract
The purpose of this study was to determine whether short-term training cessation resulted in reduced GLUT-4 protein levels. Endurance- (n = 12, ET) and strength-trained (n = 12) individuals (ST) were examined before and after 14 days of training withdrawal. GLUT-4 content was determined from muscle biopsy samples of the gastrocnemius in ET and the vastus lateralis in ST. Insulin sensitivity (oral glucose tolerance test) was significantly (P < 0.05) reduced in ET and ST with training cessation. GLUT-4 content was unaltered (P > 0.05) in both groups (92 and 100% of trained values for ET and ST, respectively). In ET, citrate synthase activity decreased significantly (P < 0.05) with training withdrawal (41.0 +/- 3.6 vs. 30.6 +/- 2.8 mumol.g-1.min-1); in ST no change was evident. The decrement in insulin sensitivity with the cessation of endurance- or resistance-oriented activity is therefore not associated with a reduction in GLUT-4 protein content. Muscle oxidative capacity and GLUT-4 content do not coincide with the removal of endurance training.
- Published
- 1993
- Full Text
- View/download PDF
29. Effects of exercise cessation on lipids and lipoproteins in distance runners and power athletes.
- Author
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Hortobágyi T, Houmard JA, Israel RG, Carpenter JW, Heath J, and Barakat HA
- Subjects
- Adolescent, Adult, Humans, Male, Physical Endurance, Running, Weight Lifting, Lipids blood, Lipoproteins blood, Physical Exertion, Rest
- Abstract
The purpose of this study was to determine the effects of short-term exercise cessation on lipid and lipoprotein profile and insulin sensitivity in highly trained runners (n = 12; mean age 19.9 years) and power athletes (n = 12; mean age 24.4 years). Following 14 days of exercise cessation, running time to exhaustion and maximal oxygen uptake decreased by 9.2% and 4.8% (P < 0.05) in the runners, while in the power athletes one repetition maximum squat and bench press did not change (P > 0.05). No changes occurred in body composition. Data from a 2-h oral glucose tolerance test revealed an impairment of the glycemic state in all athletes (P < 0.05). In contrast, exercise cessation did not significantly (P > 0.05) alter plasma levels of cholesterol, triglycerides, and low density (LDL) and high density lipoprotein (HDL). No changes were observed in HDL2, HDL2b, and HDL3 subfractions, LDL diameter, and qualitative LDL pattern (P > 0.05). These data thus suggest that despite a decrease in insulin sensitivity, short-term exercise cessation, independent of exercise mode, was insufficient to alter plasma lipid and lipoprotein profiles in well-trained athletes.
- Published
- 1993
- Full Text
- View/download PDF
30. Comparison of four methods to assess body composition in black and white athletes.
- Author
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Hortobágyi T, Israel RG, Houmard JA, O'Brien KF, Johns RA, and Wells JM
- Subjects
- Adolescent, Adult, Body Height, Body Mass Index, Densitometry, Electric Impedance, Female, Football, Humans, Male, Regression Analysis, Skinfold Thickness, Spectrophotometry, Infrared, Black People, Body Composition, Sports, White People
- Abstract
Four methods of assessing body composition were compared in 55 black and 35 white, Division I, American football players. Percent body fat (%BF) was estimated with hydrostatic weighing at residual volume, corrected for race; seven-site skinfolds (7 SF), corrected for race; bioelectrical impedance analysis (BIA); and near-infrared spectrophotometry (NIR). Percent body fat with HW in blacks (mean = 14.7%) and whites (19.7%) did not differ (P > .05) from %BF with 7 SF (blacks, 14.7%; whites, 19.0%). In relation to HW, BIA significantly (P < .05) overpredicted (blacks: 20.1%, SEE = 3.2%; whites: 22.3%, SEE = 4.3%) and NIR underpredicted %BF (blacks: 12.6%, SEE = 3.9%; whites: 17.7%, SEE = 3.6%). The contribution of BIA variables (resistance, phase angle, conductance) and NIR optical density to predict %BF was trivial compared to body mass index. It appears that race may not substantially influence %BF prediction by NIR and BIA. It was concluded that when considering the cost and expertise required with NIR and BIA, SF measurements appear to be a superior alternative for rapid and accurate body composition assessment of athletes, independent of race.
- Published
- 1992
- Full Text
- View/download PDF
31. Comparison of body composition assessment by hydrodensitometry, skinfolds, and multiple site near-infrared spectrophotometry.
- Author
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Hortobágyi T, Israel RG, Houmard JA, McCammon MR, and O'Brien KF
- Subjects
- Adipose Tissue, Adolescent, Adult, Anthropometry, Humans, Male, Middle Aged, Predictive Value of Tests, Regression Analysis, Body Composition, Densitometry methods, Skinfold Thickness, Spectrophotometry, Infrared methods
- Abstract
Percent body fat (%BF) was assessed in 171 men with underwater weighing (UWW), seven-site skinfolds (7 SF), and near-infrared spectrophotometry (NIR). NIR was determined at eight sites, including biceps, triceps, axilla, chest, abdomen, suprailium, subscapula and thigh. Analysis of variance and Dunnett's post-hoc procedure revealed that NIR significantly (P less than 0.05) underpredicted %BF when using the biceps (12.9%), chest (11.3%), abdomen (10.2%), subscapula (11.3%) and thigh (9.9%) sites compared to the criterion %BF measured with UWW (13.4% +/- SD = 6.49). %BF with 7 SF was only 0.3% higher than %BF with UWW (r = 0.94, standard error of estimate = 2.9%). Correlation coefficients between SF thickness and NIR optical density readings at 940 nm (OD1) and 950 nm (OD2) wavelengths ranged from r = -0.30 (subscapula) to r = -0.67 (biceps) for OD1 and r = -0.39 (axilla) to r = -0.68 (biceps) for OD2. Multiple linear regression showed that the OD readings were not significant predictors of UWW %BF when using body mass, stature, activity level, and frame size as predictors, except for the OD2 reading at the biceps site. Stepwise regression revealed that NIR OD readings did not predict additional variance in %BF beyond mass, stature, activity level, frame size, or 7 SF. It was concluded that 7 SF are better predictors of %BF than NIR, and that NIR at multiple sites is inconsistent in assessing body composition.
- Published
- 1992
32. Elevated skeletal muscle glucose transporter levels in exercise-trained middle-aged men.
- Author
-
Houmard JA, Egan PC, Neufer PD, Friedman JE, Wheeler WS, Israel RG, and Dohm GL
- Subjects
- Adult, Aged, Blood Glucose analysis, Glucose Tolerance Test, Humans, Insulin blood, Insulin physiology, Male, Middle Aged, Physical Education and Training, Time Factors, Monosaccharide Transport Proteins metabolism, Muscles metabolism
- Abstract
Exercise training has been proposed to improve whole body insulin sensitivity through a postreceptor adaptation in skeletal muscle. This study examined if levels of the insulin-responsive muscle glucose transporter protein (GLUT-4) were associated with improved insulin sensitivity in trained vs. sedentary middle-aged individuals. Muscle GLUT-4 levels and oral glucose tolerance test (OGTT) responses were obtained in age-matched trained and sedentary men (n = 11). Plasma insulin levels during the OGTT were significantly lower (P less than 0.01) in the trained men, whereas no differences were seen in plasma glucose responses. GLUT-4 protein content was approximately twofold higher in the trained men (2.41 +/- 0.17 vs. 1.36 +/- 0.11 micrograms standard, P less than 0.001). OGTT responses and GLUT-4 levels were not altered 15-18 h after a standard exercise bout in six representative sedentary subjects. These data suggest that GLUT-4 levels are increased in conjunction with insulin sensitivity in chronically exercise-trained middle-aged men. This finding suggests a possible mechanism for the improved insulin sensitivity observed with exercise training in humans.
- Published
- 1991
- Full Text
- View/download PDF
33. Peak running velocity, submaximal energy expenditure, VO2max, and 8 km distance running performance.
- Author
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Houmard JA, Craib MW, O'Brien KF, Smith LL, Israel RG, and Wheeler WS
- Subjects
- Adult, Heart Rate, Humans, Male, Energy Metabolism, Oxygen Consumption physiology, Physical Endurance physiology, Running
- Abstract
The purposes of this study were to examine (1) if the peak running velocity achieved during maximal treadmill testing is related to 8 km distance running performance (DRP) and (2) if the relationship between selected physiological determinants are consistant for two 8 km races within a competitive season. Seven members of a University cross-country team (mean +/- SE) (age, 19.4 +/- 0.5 years, VO2max 67.0 +/- 1.0 ml/kg/min were tested 2-3 days following a mid-season race (Race M) and the season-ending conference championship (Race C). Despite similar weather and terrain, Race C (29:22 +/- 1:22 min:sec) was significantly (p less than 0.05) slower than Race M (28:31 +/- 0:58 min:sec). However, no significant differences (p greater than 0.05) were observed between testing sessions for calculated energy expenditure heart rate oxygen consumption and RER during submaximal running (248 and 268 m/min), postsubmaximal run lactate, peak running velocity, and VO2max. A significant correlation (p less than 0.05) was observed for Race M with with calculated energy expenditure during submaximal running at both speeds (r = 0.85) and with peak running velocity (r = -0.76). Regression analysis revealed that 92% of the total variance for Race M was accounted for by calculated energy expenditure during submaximal running and VO2max. No significant correlation or regression relationship was observed for any variables with Race C. These results suggest that peak running velocity, calculated energy expenditure during submaximal running, and VO2max can be associated with 8 km running performance. However, the relationship between 8 km DRP and the variables measured can differ for two races over a competitive season.
- Published
- 1991
34. Effects of fitness level and the regional distribution of fat on carbohydrate metabolism and plasma lipids in middle- to older-aged men.
- Author
-
Houmard JA, Wheeler WS, McCammon MR, Holbert D, Israel RG, and Barakat HA
- Subjects
- Abdomen anatomy & histology, Aged, Aging blood, Aging metabolism, Anthropometry, Glucose Tolerance Test, Hip anatomy & histology, Humans, Male, Middle Aged, Oxygen Consumption, Adipose Tissue anatomy & histology, Aging physiology, Carbohydrate Metabolism, Lipids blood, Physical Fitness
- Abstract
Many cross-sectional studies have demonstrated the influences of fitness level or the regional distribution of fat on lipid and carbohydrate metabolism; however, the relative contribution of these two variables in the same subjects has not been extensively examined. The purpose of this study was to determine the impact of regional adiposity on plasma lipids and carbohydrate metabolism in middle- to older-aged men with a wide range of fitness levels. Forty-six sedentary and exercise-trained men (age [mean +/- SE], 52.8 +/- 0.88 years) were included in this study. Fitness level was assessed by (a) time to exhaustion, and (2) maximal oxygen uptake achieved during an incremental treadmill test. Plasma lipid levels were determined in the basal, fasting state. Carbohydrate metabolism was evaluated by the glucose and insulin responses (total glucose and insulin areas under the curve, insulin sensitivity index [ISI]) to a 75-g, 2-hour oral glucose tolerance test (OGTT). Abdomen to hip ratio (AHR) was used as the index of regional adiposity. Multiple regression analysis indicated that fitness level and the percentage of body fat were significant predictors (approximately 56% of total variance) for total insulin area under the curve and the ISI. A comparison between the sedentary and trained subjects showed that training resulted in an improved ISI at an equal AHR. Fitness level was also the only significant multiple regression predictor for high-density lipoprotein (HDL)-cholesterol (25% of total variance) and accounted for the greatest amount of variance in triglyceride levels (34%), although AHR was also a significant predictor (6%).(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1991
- Full Text
- View/download PDF
35. Gastric emptying during 1 h of cycling and running at 75% VO2max.
- Author
-
Houmard JA, Egan PC, Johns RA, Neufer PD, Chenier TC, and Israel RG
- Subjects
- Analysis of Variance, Beverages, Blood Glucose metabolism, Dietary Carbohydrates administration & dosage, Drinking, Humans, Male, Plasma Volume, Sweating, Bicycling, Gastric Emptying, Oxygen Consumption, Physical Endurance physiology, Running
- Abstract
The purpose of this study was to compare gastric emptying (GE) responses during intense, prolonged cycling and running. It is important to discern whether gastric emptying (GE) responses are exercise-mode specific, since the findings of cycling and running studies are often compared and applied to one another. Ten male biathletes cycled (CY) and ran (R) for 1 h at 75% of their mode-specific VO2max or rested (S) and consumed water (SW, CYW, RW) or a 7% carbohydrate solution (SC, CYC, RC) at a rate of 10 ml.kg-1.h-1 (approximately 180 ml at 0, 15, 30, and 45 min). No differences were found between CYW, CYC, RW, RC, and SC for volume of drink emptied (mean +/- SE) (522.8 +/- 47.9 ml) and GE rate (range, 8.2 +/- 0.9 (RC) to 9.3 +/- 0.6 ml.min-1 (SC]. A mean of 72.7 +/- 5.7% of the total consumed volume was emptied. The GE rate during SW was significantly (P less than 0.05) greater than the other conditions (11.3 +/- 0.4 ml.min-1, 94.0 +/- 1.9% of total consumed volume emptied). Substantial volumes of water and a 7% carbohydrate solution are thus emptied from the stomach during prolonged, intense running and cycling, with no differences in GE between these exercise modes. These data suggest that recommendations concerning GE are reciprocal between running and cycling bouts similar to those in the current study.
- Published
- 1991
36. An evaluation of waist to hip ratio measurement methods in relation to lipid and carbohydrate metabolism in men.
- Author
-
Houmard JA, Wheeler WS, McCammon MR, Wells JM, Truitt N, Hamad SF, Holbert D, Israel RG, and Barakat HA
- Subjects
- Body Composition physiology, Body Mass Index, Cholesterol blood, Coronary Disease blood, Diabetes Mellitus, Type 2 blood, Glucose Tolerance Test, Humans, Insulin Resistance physiology, Lipoproteins, HDL blood, Lipoproteins, LDL blood, Male, Middle Aged, Obesity blood, Oxygen blood, Physical Fitness physiology, Risk Factors, Triglycerides blood, Anthropometry methods, Blood Glucose metabolism, Coronary Disease etiology, Diabetes Mellitus, Type 2 etiology, Lipids blood, Obesity etiology
- Abstract
The purpose of this study was to determine which method of measuring waist to hip ratio (WHR) was the most effective in assessing decrements associated with an abdominal fat distribution in 46 non-obese, middle to older aged men (mean +/- s.e., age 52.8 +/- 0.88 years; body fat 19.7 +/- 0.72 percent). Circumferences were obtained at the following sites and WHR calculated (waist circumference/hip circumference): (1) minimal waist/maximal hip; (2) level of umbilicus/maximal hip; (3) level of umbilicus/level of greater trochanters; (4) level of umbilicus/level of superior iliac spine; and (5) level of 1/3 of the distance between the xiphiod process and umbilicus/level 4 cm below the superior iliac spine. Significant (P less than 0.05) associations were observed for measurement methods 1, 2 and 3 with indices of lipid and carbohydrate metabolism, body composition, and fitness level. Measurement method 5 was not related to any metabolic or physiological variables, while measurement method 4 was intermediate in terms of the strength of the associations. These findings suggest that the predictive strength of WHR can vary depending upon the measurement method used.
- Published
- 1991
37. Sensitivity and specificity of current methods for classifying morbid obesity.
- Author
-
Israel RG, Pories WJ, O'Brien KF, and McCammon MR
- Subjects
- Adult, Body Composition physiology, Body Mass Index, Body Weight physiology, Female, Humans, Middle Aged, Obesity, Morbid pathology, Obesity, Morbid physiopathology, Densitometry methods, Obesity, Morbid classification
- Abstract
This study examined the sensitivity and specificity of current methods for classifying morbid obesity in females. Results suggest that current methods for classifying morbid obesity (greater than or equal to 45.5 kg over ideal weight or BMI greater than or equal to 45) do not provide acceptable specificity and sensitivity, respectively. We suggest that additional measurements such as total body fatness determined by hydrodensitometry be used to classify morbid obesity and determine eligibility for aggressive therapeutic interventions for weight loss.
- Published
- 1990
- Full Text
- View/download PDF
38. Comparison between two methods of hydrostatic weighing without head submersion in morbidly obese females.
- Author
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Israel RG, Evans P, Pories WJ, O'Brien KF, and Donnelly JE
- Subjects
- Body Composition physiology, Female, Head anatomy & histology, Humans, Immersion, Obesity, Morbid complications, Obesity, Morbid pathology, Statistics as Topic, Body Weight physiology, Obesity, Morbid physiopathology
- Abstract
This study compared two methods of hydrostatic weighing without head submersion to conventional hydrostatic weighting in morbidly obese females. We concluded that hydrostatic weighing without head submersion is a valid alternative to conventional hydrostatic weighing especially when subjects are apprehensive in the water. The use of anthropometric head measures (HWNS-A) did not significantly improve the accuracy of the body composition assessment; therefore, elimination of these time consuming measurements in favor of the direct correction of head above Db is recommended.
- Published
- 1990
- Full Text
- View/download PDF
39. Criteria to verify attainment of maximal exercise tolerance test with obese females.
- Author
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Donnelly JE, Jakicic J, Roscoe M, Jacobsen DJ, and Israel RG
- Subjects
- Adult, Cardiovascular System physiopathology, Exercise Test standards, Female, Heart Rate physiology, Humans, Middle Aged, Oxygen Consumption physiology, Pulmonary Gas Exchange physiology, Exercise physiology, Obesity physiopathology
- Abstract
This study compared criteria used to determine attainment of maximal ETT used with normal subjects to results shown by obese subjects. Results indicated that obese subjects do not show the values that normal subjects show for plateau in oxygen consumption, respiratory exchange ratio, predicted maximal heart rate, or perceived exertion. Generally, less than 60% of the obese subjects met criteria for maximal ETT. These findings suggest that alternate criteria and/or alternate testing are needed to ascertain that ETT was maximal. Suggestions include longer treadmill stage times and the use of blood lactate.
- Published
- 1990
- Full Text
- View/download PDF
40. Response time comparisons among four base running starting techniques in slow pitch softball.
- Author
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Israel RG and Brown RL
- Subjects
- Adolescent, Adult, Biomechanical Phenomena, Humans, Male, Baseball, Running, Sports
- Published
- 1981
- Full Text
- View/download PDF
41. Validity of a near-infrared spectrophotometry device for estimating human body composition.
- Author
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Israel RG, Houmard JA, O'Brien KF, McCammon MR, Zamora BS, and Eaton AW
- Subjects
- Adolescent, Adult, Analysis of Variance, Humans, Male, Middle Aged, Reproducibility of Results, Skinfold Thickness, Body Composition, Spectrophotometry, Infrared standards
- Published
- 1989
- Full Text
- View/download PDF
42. Exercise effects on fitness, lipids, glucose tolerance and insulin levels in young adults.
- Author
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Israel RG, Davidson PC, Albrink MJ, and Krall JM
- Subjects
- Adolescent, Adult, Blood Glucose, Blood Pressure, Heart Rate, Humans, Insulin blood, Lipids blood, Male, Skinfold Thickness, Physical Education and Training, Physical Fitness
- Abstract
The effect of 3 different physical training programs on cardiorespiratory (cr) fitness, fasting plasma lipids, glucose and insulin levels, and scapular skinfold thickness was assessed in 64 healthy college men. Training sessions were held 4 times a week for 5 weeks. The cr fitness improved significantly and skinfold thickness decreased following the aerobic, the pulse workout (interval training), and the anaerobic training compared to the control group. Skinfold thickness, plasma insulin, and triglyceride concentrations were significantly intercorrelated before and after training. The exercise programs had no significant effect on plasma cholesterol, triglycerides, phospholipids, glucose tolerance, or insulin levels. Change in adipose mass was thus dissociated from change in plasma insulin and triglyceride concentrations. It was concluded that in young men plasma triglycerides, the lipid component mostly readily reduced by exercise, were too low to be reduced further by a physical training program.
- Published
- 1981
43. White blood cell response to uphill walking and downhill jogging at similar metabolic loads.
- Author
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Smith LL, McCammon M, Smith S, Chamness M, Israel RG, and O'Brien KF
- Subjects
- Adolescent, Adult, Exercise Test, Heart Rate, Humans, Hydrocortisone blood, Leukocyte Count, Male, Neutrophils analysis, Oxygen Consumption, Radioimmunoassay, Time Factors, Exercise, Leukocytosis etiology, Muscles physiology
- Abstract
The object of this study was to determine whether leukocytosis would occur in response to eccentric exercise, to concentric exercise, and/or to possible increases in serum cortisol levels. Eight men performed 2 bouts of exercise at 46% VO2max for 40 min. Subjects initially walked up a 10% grade (UW); 2 weeks later they jogged down a 10% grade (DJ), a form of eccentric exercise known to induce delayed onset muscle soreness (DOMS). Venous blood samples were drawn before and after each exercise bout (0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, and 5 h). Total and differential WBCc and serum cortisol levels were assessed. Results were analyzed using repeated measures ANOVA (2 x 11). Subjects experienced severe DOMS after DJ. There was a significant difference in TWBCc (p less than 0.0001) between UW and DJ. Post-hoc testing revealed no significant increase over baseline values for UW; after DJ there was a 46% increase over baseline values (p less than 0.05) initially seen at 1.0 h. These increases in TWBCc were predominantly a reflection of increases in neutrophils which were significant (p less than 0.0001) when compared to baseline values at 1.0, 1.5 and 2.0 h (approximately 60%). No significant neutrophil increases were seen after UW. Cortisol levels were similar for both groups pre-exercise (UW = 367.1 +/- 38.6, DJ = 320.2 +/- 44.16 nmol.L-1 means +/- SE) and decreased similarly for both groups after exercise, and thus were not related to the post-exercise neutrophilia.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1989
- Full Text
- View/download PDF
44. Alterations in low-density lipoproteins in subjects with abdominal adiposity.
- Author
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Peeples LH, Carpenter JW, Israel RG, and Barakat HA
- Subjects
- Adipose Tissue ultrastructure, Adult, Body Mass Index, Coronary Disease etiology, Electrophoresis, Polyacrylamide Gel, Humans, Lipids analysis, Lipoproteins, LDL isolation & purification, Lipoproteins, LDL ultrastructure, Male, Middle Aged, Molecular Weight, Particle Size, Proteins analysis, Risk, Specific Gravity, Ultracentrifugation, Abdomen, Lipoproteins, LDL metabolism, Obesity metabolism
- Abstract
Abdominal adiposity, as indexed by the waist to hip girth ratio (WHR), has been associated with increased risk and incidence of coronary heart disease (CHD). The purpose of this study was to determine if this enhanced risk is related to alterations in the structure of low density lipoproteins (LDL). LDL were isolated from nine nonobese men with an average WHR of 1.046 and nine nonobese men with a WHR of 0.94, who were matched on age (45.6 +/- 2.7 v 47.7 +/- 2.3 mean +/- SEM) percent body fat (26.5 +/- 0.5 v 26.1 +/- 0.9), and body mass index (27.3 +/- 0.6 v 26.3 +/- 0.6). The average molecular weight of LDL from the subjects with a high WHR was lower than that of subjects with low WHR (2.70 v 3.02 x 10(6) d), the average hydrated density higher (1.050 v 1.040 g/mL), and the mobility (Rf) on 2% to 16% polyacrylamide gradient gel electrophoresis higher. Subfractionation by equilibrium density ultracentrifugation showed that the LDL of subjects with a high WHR was predominantly in the heavy density range (1.038 to 1.048 g/mL) compared with the LDL of subjects with low WHR, which was in the lighter density range (1.030 to 1.040 g/mL). Chemical analysis of the subfractions showed that the peak density fractions of LDL of subjects with a high WHR had a lower cholesterol to protein ratio than the peak density fractions of LDL of subjects with low WHR. Electron microscopy of these peak density fractions showed that LDL of subjects with high WHR was smaller than that of subjects with low WHR. These characteristics of LDL of subjects with abdominal adiposity closely resemble the properties of LDL of patients with documented CHD. It is concluded that the increased risk of CHD associated with abdominal adiposity may be due in part to the alterations in LDL characteristics, and that these alterations in LDL are independent of the degree of obesity.
- Published
- 1989
- Full Text
- View/download PDF
45. Body fat distribution, plasma lipoproteins and the risk of coronary heart disease of male subjects.
- Author
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Barakat HA, Burton DS, Carpenter JW, Holbert D, and Israel RG
- Subjects
- Adipose Tissue metabolism, Adult, Aged, Apoproteins blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Exercise Test, Humans, Male, Middle Aged, Risk Factors, Anthropometry, Coronary Disease blood, Lipoproteins blood
- Abstract
Recent studies have related waist to hip ratio (WHR) to the incidence of coronary heart disease (CHD), but the causes underlying this relation are not fully known. The purpose of this study was to determine if waist to hip ratio is associated with the concentration of plasma lipids and apolipoproteins (apoproteins) that predispose individuals to a higher CHD risk. Plasma lipids and apoprotein concentrations were determined in 100 male volunteers, ranging in age from 19-68 yr, and WHR ranging from 0.89-1.09. Significant positive associations were found between WHR, plasma glucose (r = 0.25, P = 0.01), cholesterol (r = 0.21, P = 0.04), LDL cholesterol (r = 0.22, P = 0.03), triglycerides (r = 0.25, P = 0.01) and the ratio of total cholesterol to HDL-cholesterol (r = 0.30, P = 0.002). Negative associations were found between WHR and HDL-cholesterol (r = -0.19, P = 0.05), plasma apoprotein A-I (4 = -0.28, P = 0.005) and the ratio of plasma apoprotein A-I to apoprotein B (r = -0.26, P = 0.01). To determine the extent to which these correlations were independent of age and body fat content, a subsample of 15 pairs matched on age and percent body fat, but differing in WHR was selected from the larger sample. In the group with high WHR (1.06) HDL-cholesterol and apo A-I levels were lower and apo B higher than in the group with low WHR (0.96). Total cholesterol, triglycerides and LDL cholesterol levels in the group with high WHR were also higher but marginally significant statistically. These results show that WHR is associated with plasma lipid and apolipoprotein concentrations that are more predisposing to CHD and that males with male type obesity may be at a higher risk of CHD development than those with female type, regardless of age or degree of obesity.
- Published
- 1988
46. Time comparison between the cross-over and jab-step starts.
- Author
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Israel RG
- Subjects
- Adult, Humans, Male, Task Performance and Analysis, Time Factors, Baseball, Sports
- Published
- 1979
47. Effect of carbohydrate ingestion on exercise endurance and metabolism after a 1-day fast.
- Author
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Riley ML, Israel RG, Holbert D, Tapscott EB, and Dohm GL
- Subjects
- Adult, Fasting, Fatty Acids blood, Humans, Male, Oxygen Consumption, Carbohydrates pharmacology, Physical Endurance
- Abstract
Fasting before an exercise event has been demonstrated to decrease endurance. The purpose of this study was to investigate whether this decrement in performance after fasting could be reversed by ingestion of a carbohydrate solution before and during exercise. Nine fit male subjects ran to exhaustion at approximately 70% VO2max in two counterbalanced trials. The subjects were fasted for 21 h before both trials, and the trials were arranged so that the subjects ingested either a carbohydrate (CHO) or placebo (PL) solution. Although ratings of perceived exertion were significantly lower in the CHO trial, there were no differences in endurance time to exhaustion in the two trials (102 +/- 8 min in the PL trial and 106 +/- 8 min in the CHO trial). There were no differences between trials for the VO2, heart rate, and blood lactate concentrations. As expected, the blood glucose and insulin concentrations were higher in the CHO trial. The respiratory exchange ratio was significantly higher in the CHO trial at 40 min of exercise and tended to be higher at all other times, suggesting a greater reliance on carbohydrate and less on fat as an energy source. This seemed to be confirmed by the significantly lower plasma glycerol concentration, which suggested less fat mobilization in the CHO trial. Ingestion of a glucose polymer solution increased carbohydrate utilization in fasted subjects, but exercise performance was not improved.
- Published
- 1988
- Full Text
- View/download PDF
48. Hydrostatic weighing without head submersion: description of a method.
- Author
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Donnelly JE, Brown TE, Israel RG, Smith-Sintek S, O'Brien KF, and Caslavka B
- Subjects
- Adolescent, Adult, Body Composition, Female, Humans, Hydrostatic Pressure, Male, Methods, Random Allocation, Residual Volume, Total Lung Capacity, Body Weight, Immersion
- Abstract
Hydrostatic weighing (HW) was performed at residual volume (RV) and total lung capacity without head submersion (TLCNS). Ninety-five males (25.6 +/- 4.9 yr) and 87 females (22.6 +/- 5.2 yr) were studied at two laboratory sites using identical protocols. Twenty males and 20 females were separated from the original group and randomly assigned to cross-validation groups. RVs were determined by the oxygen dilution method. Vital capacity was determined with the subject submerged in water to the shoulders. Underwater weight was determined using 10 trials at RV and 5 trials at TLCNS, with the order of methods randomly assigned. Regression analysis provided an equation to predict body density (pDb) at RV from body density (Db) at TLCNS. The equation for males was pDb (HW at RV) = 0.5829 (DbHW at TLCNS) + 0.4059, r = 0.88, SEE = 0.0067. The equation for females was pDb (HW at RV) = 0.4745 (DbHW at TLCNS) + 0.5173, r = 0.85, SEE = 0.0061. Cross-validation showed no significant differences using Db from HW at RV (males = 1.0626 g.ml-1, females = 1.0493 g.ml-1 and pDb from HW at TLCNS (males = 1.0625 g.ml-1, females = 1.0479 g.ml-1). The correlation coefficient SEE and total error for males were r = 0.95, 0.0043, and 0.0041, respectively and for females r = 0.82, 0.0084, and 0.0085, respectively. Mean percent fat for RV and TLCNS was identical for males and differed by 0.7% for females. Test-re-test data indicated the TLCNS procedure was reliable (r = 0.98).(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1988
- Full Text
- View/download PDF
49. Biphasic changes in 3-methylhistidine excretion in humans after exercise.
- Author
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Dohm GL, Israel RG, Breedlove RL, Williams RT, and Askew EW
- Subjects
- Creatinine urine, Female, Humans, Male, Periodicity, Time Factors, Histidine analogs & derivatives, Methylhistidines metabolism, Physical Endurance, Physical Exertion
- Abstract
We previously reported that 3-methylhistidine excretion was increased in human subjects after a strenuous bout of exercise. Because other investigators have not corroborated this finding, we undertook the present study to investigate the conditions that result in decreased and increased 3-methylhistidine excretion in human subjects after exercise. Four experiments were performed: a cross-sectional study comparing 3-methylhistidine excretion in endurance-trained subjects with untrained controls, a longitudinal study of 3-methylhistidine excretion by female basketball players before the start of the season and again during the competitive season, an experiment to determine changes in 3-methylhistidine excretion as a result of 2 h of exercise each day for 7 consecutive days, and a study to determine changes in 3-methylhistidine excretion during 4-h intervals after a strenuous exercise bout. The 3-methylhistidine-to-creatinine ratio was approximately 20% higher for trained than nontrained subjects. In three separate experiments a biphasic change of 3-methylhistidine excretion was observed in response to exercise with an immediate decrease in the 3-methylhistidine-to-creatinine ratio during exercise followed by a prolonged increase. The magnitudes of the negative and positive responses determine whether one observes an increase, no change, or a decrease in the total daily excretion of 3-methylhistidine.
- Published
- 1985
- Full Text
- View/download PDF
50. Relationship between body mass indices and measures of body adiposity.
- Author
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Revicki DA and Israel RG
- Subjects
- Adult, Aged, Body Height, Body Weight, Humans, Male, Middle Aged, Skinfold Thickness, Adipose Tissue, Body Constitution
- Abstract
We examined the relationship between various body mass indices (BMIs), skinfold measures, and laboratory measures of body fat in 474 males aged 20-70 years. Evaluations included height, weight, skinfold thickness, and hydrostatic measurements of adiposity. The weight-height ratio (W/H), Quetelet index (W/H2), Khosla-Lowe index (W/H3), and Benn index (W/HP) were calculated. The correlations among the various BMIs were high, ranging from 0.91 to 0.99, and all were strongly correlated with weight (rs = 0.81 - 0.98), while only W/H2 (r = -.03) and W/HP (r = -.01) were not correlated with height. The W/H2 and W/HP had the strongest correlation with hydrostatic and skinfold measurements, although all the BMIs were significantly correlated with these measurements. Results suggest that the Benn index and the Quetelet index are equally valid estimates of body fat in respect to their relationship with hydrostatic measures.
- Published
- 1986
- Full Text
- View/download PDF
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