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Biomedical subjects

V L Katch

Publications and source records attributed to V L Katch.

At least 19 recordsLinked to original sources
PubMed1995

Validity of a new portable indirect calorimeter: the AeroSport TEEM 100.

The purpose of this study was to compare oxygen uptake (VO2) values collected with a new portable indirect calorimeter (AeroSport TEEM 100 Metabolic Analysis System) against a more traditional large calorimeter system that has been reported to be valid and reliable (SensorMedics 2900 Metabolic Measurement Cart). Minute ventilations ranging from rest up to heavy exercise were compared with simultaneous measurements from a 120-1 Tissot gasometer. Each of the three TEEM 100 pneumotachs were tested. Three hundred and sixty-one separate ventilation tests were performed using the low-flow, medium-flow, and high-flow heads of the portable calorimeter. For each of the pneumotachs, the correlation between the portable calorimeter values and the gasometer values exceeded r = 0.94. The standard error of estimate for the low-medium- and high-flow pneumotach were 5.96, 4.89 and 9.0%, respectively, expressed relative to the mean gasometer value. Simultaneous measurements of VO2 using the portable calorimeter and the SensorMedics 2900 unit were compared during rest and at work rates starting at zero watts, increasing by 25 W to 150 W. Each work rate was of 4 min duration. The average of data from minutes 3 and 4 were used in all analyses. There was very close agreement between the two metabolic measurement systems. Except at the 100-W work rate, where the VO2 difference was small (3.9%), yet statistically significant, all of the other differences in VO2 were small and non-significant. The scatter plot of VO2 for the SensorMedics versus the portable Aero-Sport calorimeter revealed close agreement; the correlation was r = 0.96, (SEE = 3.95%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Individuals with amyotrophic lateral sclerosis are in caloric balance despite losses in mass.

The purpose of this study was to quantify body composition changes during amyotrophic lateral sclerosis (ALS) progression and to determine whether these subjects were losing or maintaining the energy stored in their bodies. The body composition of 12 males in the early stages of ALS and 6 age-matched controls was measured twice over a 6-month period using dual X-ray absorptiometry. During the study period the control group did not change. The ALS group lost an average of 2 kg of lean mass while gaining 0.55 kg of fat mass, resulting in a 1.45 kg loss in total body mass. When the changes in mass were converted to their energy equivalents, the ALS subjects lost an average of 1800 kcal of energy stored in lean mass but gained 4900 kcal in fat mass, resulting in a net increase of 3100 kcal stored. In conclusion, a small increase in fat mass can successfully compensate for the energy lost in lean mass from disease progression. Therefore, it is possible to preserve the amount of energy stored in the body of ALS patients, even when there are significant losses in lean and overall body mass. Consequently, a moderate loss of body mass should be expected and even encouraged among this patient population.

Absorptiometry, Photon↗
PubMed1992

Reduced short-term thermic effects of a meal in obese adolescent girls.

Post-meal energy expenditure (TEM) was compared for 14 healthy obese (body fat = 45.3%, body mass index, BMI = 35.9 kg m-2) and 9 healthy nonobese (body fat = 20.7%, BMI = 17.8 kg m-2) adolescent girls. The test meal for both groups was a standard 3348.8-kJ, 0.473-1 chocolate milkshake of 15% protein (casein), 40% fat (polyunsaturated/saturated ratio = 0.05; 75 mg cholesterol) and 45% carbohydrate (lactose and sucrose). Glucose, insulin and resting energy expenditure (RMR) were measured at rest prior to meal consumption and 20, 40, 60, 90, and 120 min after the meal. Cumulative net TEM was calculated as the integrated area under the TEM curve with RMR as baseline. Reliability was assessed by retesting 4 subjects, and a placebo effect was tested by administering a flavored energy-free drink. Results indicated high reliability and no placebo effect. The meal resulted in a greater rise in insulin and glucose for the obese compared to the nonobese subjects (P < or = 0.05), and a significant TEM for both groups (P < or = 0.05). The cumulative TEM (W kg-1) was 61.9% greater for the nonobese (P < 0.01) when expressed relative to body mass, and 33.2% greater for the nonobese (P < or = 0.01) when expressed relative to the fat-free body mass. Expressed relative to the meal, the TEM was 25.5% less for the obese (P < 0.01). The data support an energy conservation hypothesis for obese female adolescents.

Adolescent↗
PubMed1990

Proprioceptive facilitation of muscle tension during unilateral and bilateral knee extension.

The effects of double neuromuscular facilitation (DNF) in unilateral movements and of quadruple neuromuscular facilitation (QNF) in bilateral movements were studied in 42 physically active college-age male subjects. Results showed a 10.4% significant increase of maximal knee extension torque output when unilateral extension was preceded by a knee flexion on an isokinetic exerciser and a 16.7% increase of maximal torque in the bilateral condition of simultaneous alternating flexion-extension when compared to the simultaneous extension movement. Consequently, the increased peak torque observed in the unilateral and bilateral experimental conditions in which knee extension was preceded by a knee flexion appears to be the result of a combination of neuromuscular influences and stored elastic energy.

Adult↗
PubMed1990

Relationships of body size, segmental dimensions, and ponderal equivalents to muscular strength in high-strength and low-strength subjects.

There are conflicting results in prior studies concerning the relationships among body size, muscle size, and muscular strength. The purpose of the present study was to evaluate how body size, body shape, and segmental dimensions related to individual differences in muscular strength. Subjects were tested on four dynamic measures of strength and then classified into one of two groups as high strength (HS; N = 21) and low strength (LS; N = 21). Individual differences in strength were then related to body composition and segmental anthropometry. Strength was assessed during high-resistance, low-velocity standing squat and supine bench press with an isokinetic dynamometer, and during seated bench press and knee extension with a hydraulic resistance dynamometer. Anthropometry and body composition included 11 girths, six fatfolds, predicted fat-free mass (FFM), thigh and upper arm volume, muscle + bone cross-sectional area (CSA), and the Behnke Ponderal Somatogram (PSom) body profiling system. There was a 21.3% difference in strength between HS and LS (p less than 0.05), but no significant differences in age, stature, and fatfolds. MANOVA revealed that seven of 11 girth components of PSom were larger for HS (p less than 0.05). The correlations between strength vs body mass, FFM, thigh and upper arm volume, and CSA and fatfolds in HS and LS ranged from r = -0.52 to 0.56 (r = -0.70 to 0.70 when corrected for restriction of range). We conclude that individual differences in muscular strength are poorly related to various measures of body size and segmental body dimensions.

Adult↗
PubMed1989

Strength gains in obese females are unaffected by moderate dietary restriction.

This study examined the effects of dietary restriction on strength gains from whole body resistance training. Comparisons were made between diet-restricted (n = 12) and non-diet-restricted (n = 10) obese women (mean +/- SD, 36.7 +/- 7.0% fat) undergoing identical 8-week resistance training regimens. Diet-restricted subjects reduced their dietary intake by 4200 kJ/day and reduced body mass by 3.9 kg over 8 weeks. Ten-repetition maximum masses were compared between the groups on biweekly intervals. Results indicated no differences between the groups with respect to the rate or magnitude of strength gains for any of the eight exercises. Significant pre- to post-test increases in strength (p less than 0.05) were found for all eight exercises. The rate or magnitude of strength gains induced by resistance training does not appear to be affected by moderate dietary restrictions in obese females.

Adult↗
PubMed1989

Reliability and validity of the Omnitron hydraulic resistance exercise and testing device.

This study assessed the measurement reliability and validity of the Hydra-Fitness Omnitron, a microprocessor-controlled isokinetic ergometer that provides concentric resistance for dynamic extension and flexion movements as well as resistance for isometric contractions. Maximal peak torque output measured by the Omnitron and strain gauge devices connected to the apparatus were compared in 26 physically active males who were tested over 3 days for isometric knee extension and isokinetic knee flexion/extension at two resistance levels. Maximal torque outputs remained stable on days 2 and 3 (p less than 0.05), and intraclass reliability yielded r = 0.94 to 0.98. There was no difference between the slopes of the regression lines for the different experimental conditions (p less than 0.05). There was significant improvement between day 1 and days 2 and 3 that corresponded to a combination of a training and learning effect. Thus, one practice session was necessary to obtain reliable individual differences. The validity correlations between peak torque output measured from the Omnitron and strain gauges were greater than r = 0.94. There was a small discrepancy (0.44 to 0.88 Nm) between the two measuring devices that can be explained by the difference in shank pad positioning that accommodates for different segment lengths. We conclude that reliability and validity were excellent over a wide range of torque outputs measured during maximal isometric and maximal dynamic double concentric flexion and extension movements.

Adult↗
PubMed1989

Physiological responses to nine different exercise:rest protocols.

This study determined the metabolic responses to different exercise:rest protocols during circuit exercise using hydraulic resistance. In experiment 1, nine subjects underwent nine different 27 min exercise circuits. There were three variations of three exercise:rest protocols (2:1, 1:1, 1:2). The VO2 for the nine circuits averaged (mean +/- SEM) 1.94 +/- 0.03 l.min-1 (43% of treadmill VO2max), with the largest difference between the protocols being 13%. Heart rate averaged 152.2 +/- 3.1 beats.min-1, with the largest difference between the protocols being 8%. Increasing the exercise duration per minute or the number of exercise bouts per minute had minimal effects on the mean VO2 and heart rate response to hydraulic resistive exercise. In experiment 2, nine subjects underwent three different 9 min exercise circuits using exercise:rest protocols of 2:1, 1:1, and 1:2 while work and VO2 were simultaneously measured. Surprisingly, increases in work were not necessarily accompanied by corresponding increases in VO2.

Adult↗
PubMed1988

Resistance weight training during caloric restriction enhances lean body weight maintenance.

To assess the individual and combined effects of weight loss and weight training on body weight and body composition, 40 obese women were randomly assigned to one of four groups for an 8 wk weight-loss study. These groups were control (C); diet without exercise (DO); diet plus weight training (DPE); and weight training without diet (EO). Body weight decreased for DO (-4.47 kg) and DPE (-3.89 kg) compared with C (-0.38 kg) and EO (0.45 kg). Lean body weight (LBW) increased for EO (1.07 kg) compared with DO (-0.91 kg) and C (-0.31 kg) and for DPE (0.43 kg) compared with DO. Upper-arm muscle areas (determined by radiograph) increased for DPE (11.2 cm2) and EO (10.4 cm2) compared with C (2.7 cm2) and DO (2.1 cm2). It was concluded that weight training results in comparable gains in muscle area and strength for DPE and EO. Adding weight training exercise to a caloric restriction program results in maintenance of LBW compared with DO.

Adult↗
PubMed1988

Coronary risk incidence of obese adolescents: reduction by exercise plus diet intervention.

The incidence of coronary heart disease risk factors and the effects of 20 weeks of diet and exercise were studied in 36 obese adolescents. Values for the following risk factors were determined: serum triglyceride level, high-density lipoprotein-cholesterol level, total cholesterol level, systolic and diastolic BP, maximum work capacity, obesity, and presence of coronary heart disease in the family history. Of the subjects, 97% had four or more risk factors. Two subjects possessed all eight risk factors. The adolescents were randomly assigned to either a control, diet therapy and behavior change, or exercise, diet therapy, and behavior change group. From pre- to posttreatment, a 14.8% and 41.4% reduction in multiple risk was noted for the latter two groups, respectively. No significant difference between the control group and the diet and behavior change group was found. In contrast, the exercise-diet-behavior change group reduced multiple risk (P less than .01) more than either of the other groups. It was concluded that obese adolescents are at high risk for the development of coronary heart disease and that exercise in addition to moderate dietary restriction can result in the reduction of multiple coronary heart disease risk.

Adolescent↗
PubMed1987

Metabolic responses during hydraulic resistance exercise.

Thirteen college-age men under-went a treadmill (TM)-graded VO2max exercise test on 1 d and a 24.5-min hydraulic resistive exercise circuit on a following day. Seven exercises were performed in the following order: leg extension, bent-over row, bicep curl, squat, upright row, bench press, and behind-neck press. Each exercise was performed three times with the following work-to-rest timing: 30 s exercise, 30 s rest; 30 s exercise; 30 s rest; and 30 s exercise, 60 s rest (to allow for machine switch-over to the next exercise). Thus, each exercise took a total of 120 s, of which work was for 90 s and rest 120 s. During the circuit, heart rate averaged 153.8 b X min-1 (81.2% of TM max) and VO2 averaged 1.93 l X min-1 (41.4% of TM max). Oxygen uptake for the individual exercises ranged from 1.52 l X min-1 (32.6% of TM max) for the behind-neck-press exercise to 2.43 l X min-1 (52.1% of TM max) for the squat exercise. Heart rate ranged from 135.9 b X min-1 (71.8% of TM max) for the leg extension exercise to 163.4 b X min-1 (86.3% of TM max) for the squat exercise. Hydraulic circuit resistance exercise results in an average caloric expenditure of 40.8 kJ X min-1 (9.75 kcal X min-1).

Adult↗
PubMed1986

Role for aldosterone in blood pressure regulation of obese adolescents.

To determine the role of aldosterone in the regulation of blood pressure (BP) in obese adolescents, supine and 2-hour upright plasma renin activity (PRA), and aldosterone and cortisol were measured in 10 nonobese and 30 obese adolescents before and after a 20-week weight loss program. The obese adolescents had significantly higher supine and 2-hour upright plasma aldosterone concentrations (17 +/- 8 vs 6 +/- 2 ng/dl [p less than 0.01 supine obese vs nonobese] and 30 +/- 11 vs 14 +/- 8 ng/dl [p less than 0.01 2-hour upright]). Although PRA was not significantly different between the 2 groups of children, a given increment in PRA produced a greater increment in aldosterone in the obese adolescents. In addition, obese subjects had a significantly increased mean BP (93 +/- 12 vs 74 +/- 8, p less than 0.005) and a weak correlation between BP and plasma aldosterone concentration. Compared with an obese control group, weight loss resulted in a significant decrease in plasma aldosterone (p less than 0.01) without an associated decrease in PRA. After weight loss there was also a significant decrease in the slope of the posture-induced relation between PRA and aldosterone. In addition to weight loss being associated with a significant decrease in BP (p less than 0.01), there was a significant correlation between the change in plasma aldosterone and the change in mean BP (r = 0.538; p less than 0.002 change in upright aldosterone vs change in mean BP). Obese adolescents have an increased plasma aldosterone concentration that may be important in the regulation of their BP.

Adolescent↗
PubMed1986

Relationship of fat patterning to coronary artery disease risk in obese adolescents.

Fatness and fat patterning of 27 male and 33 female obese adolescents were identified by principal-components analysis of five skinfolds (triceps, subscapular, iliac, abdominal, and thigh). Correlations were computed between the component scores, based on the eigen vectors, and anthropometric and physiological variables. Overall fatness, component I, was highly correlated with all anthropometric and body composition variables. Also, component I significantly correlated with fasting insulin and VO2 max for both sexes and with basal metabolism and HDL-cholesterol for females and males, respectively. Extremity fat patterning, component II, was poorly correlated with all the anthropometric and physiological variables except diastolic blood pressure for the females. Upper-lower body fat patterning, component III, was correlated with the fewest physiological variables.

Adipose Tissue↗
PubMed1986

Breast volume and anthropomorphic measurements: normal values.

Fifty-five consecutive female volunteers were evaluated. Linear measurements of the breast and nipple position were determined to fixed points on the chest wall. Volume determination was done by a standard chest-wall casting technique. A highly significant difference was found between left and right breasts in the axilla-to-nipple distance and nipple-to-midline measurements. A significant difference was also found in the distance from the lowest point of the breast (patient upright) to the nipple. Analysis of the volumetric difference between right and left breasts did not achieve statistical significance.

Adolescent↗
PubMed1984

The antihypertensive effect of calorie restriction in obese adolescents: dissociation of effects on erythrocyte countertransport and cotransport.

Measures of maximal rates of lithium-sodium countertransport and frusemide-sensitive sodium and potassium cotransport have been proposed as biochemical markers for human essential hypertension. The stability of these functions over time within the same individuals has led to the suggestion that maximal transport capacities are genetically determined. The present study confirms the reproducibility of functional assays of countertransport and cotransport in human erythrocytes after overnight storage and over a six-month period in normal volunteers and provides estimates of the magnitude of technical error for each assay. A long-term dietary intervention study in a group of obese adolescents demonstrated marked increases in erythrocyte sodium levels and maximal frusemide-sensitive sodium and potassium fluxes but no changes in cell potassium or water and no effect on lithium-sodium countertransport. A correlation between the decrease in percentage of body fat and the increase in cell sodium content suggests a link between the metabolic effects of dieting and control of erythrocyte cation handling. Although the mechanism linking dietary calorie restriction and changes in erythrocyte cation metabolism is unknown, evaluation of body weight, and especially recent weight loss, is important in studies of erythrocyte transport. Conclusions regarding genetic contributions to the activities of lithium-sodium countertransport and sodium-potassium cotransport systems will be strengthened by clarification of environmental regulators.

Adolescent↗