Effect of resistance training on body composition, self-efficacy, depression, and activity in postpartum women.

This study assessed the effect of resistance training (RT) in 60 healthy postpartum women. Participants were randomized to 18 weeks of RT or an active comparison group (flexibility training). RT and flexibility training (FT) exercises were completed twice-weekly based on the American College of Sports Medicine recommendations. Study outcomes included muscular strength, body composition (dual-energy x-ray absorptiometry), exercise self-efficacy, depressive symptoms [Center for Epidemiological Studies Depression Scale (CES-D)], and physical activity (accelerometery). For completers (n = 44), the RT group showed greater strength gains than the FT group, respectively (bench press: +36% vs +8%, P < 0.001; leg press: +31% vs +7%, P < 0.01; abdominal curl-ups: +228% vs +43%, P < 0.01); however, body composition changes were not different. There was a significant group × time interaction for exercise self-efficacy (F = 5.33, P = 0.026). For CES-D score, the RT group decreased (F = 4.61, P = 0.016), while the FT group did not; however, the group × time interaction in CES-D score was not significant (F = 1.33, P = 0.255). Sedentary time decreased (F = 5.27, P = 0.027) and light-intensity activity time increased (F = 5.55, P = 0.023) more in the RT than FT group. Intent-to-treat analyses did not alter the results. Twice-weekly RT increases strength and may be associated with better exercise self-efficacy and improved physical activity outcomes compared with FT in postpartum women.

Consumption of Nuts and Seeds and Telomere Length in 5,582 Men and Women of the National Health and Nutrition Examination Survey (NHANES).

OBJECTIVES: Consumption of nuts and seeds is associated favorably with all-cause mortality. Nuts and seeds could reduce disease and prolong life by influencing telomeres. Telomere length is a good indicator of the senescence of cells. The purpose of the present study was to determine the relationship between nuts and seeds intake and leukocyte telomere length, a biomarker of biologic aging. DESIGN: Cross-sectional. SETTING AND PARTICIPANTS: A total of 5,582 randomly selected men and women from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, were studied. MEASUREMENTS: DNA was obtained via blood samples. Telomere length was assessed using the quantitative polymerase chain reaction method. A validated, multi-pass, 24-h recall dietary assessment, administered by NHANES, was employed to quantify consumption of nuts and seeds. RESULTS: Nuts and seeds intake was positively and linearly associated with telomere length. For each 1-percent of total energy derived from nuts and seeds, telomere length was 5 base pairs longer (F=8.6, P=0.0065). Given the age-related rate of telomere shortening was 15.4 base pairs per year (F=581.1, P<0.0001), adults of the same age had more than 1.5 years of reduced cell aging if they consumed 5% of their total energy from nuts and seeds. CONCLUSIONS: Consumption of nuts and seeds accounts for meaningful decreases in biologic aging and cell senescence. The findings reinforce the recommendations of the 2015-2020 Dietary Guidelines for Americans, which encourage the consumption of nuts and seeds as part of a healthy diet.

Dietary fat and body fat: a multivariate study of 205 adult females.

This study examined the association between diet composition, particularly dietary fat intake, and body-fat percentage in 205 adult females. Subjects completed a written questionnaire regarding lifestyle factors, such as exercise participation and smoking, demographic data, and the diet section of the National Cancer Institute's Health Habits and History Questionnaire by Block. Skinfold-thickness measures were used to ascertain the body-fat percentage of each subject. Results showed that intake of dietary fat was related significantly with adiposity, without (F = 13.65, R2 = 0.063, P = 0.0003) and with (F = 8.74, R2 = 0.033, P = 0.0035) control for multiple potential confounding factors: age, total energy intake, total exercise time per week, years of regular physical activity, consumption of other macronutrients, and smoking. Unlike dietary fat intake, protein consumption and carbohydrate intake were not significant individual predictors of body-fat percentage when the potential confounding variables were controlled. The findings suggest that dietary fat intake may play a role in obesity beyond dietary energy content.

Attention and oculomotor control: a high-density ERP study of the gap effect.

In a gap paradigm, healthy adult subjects performed visually triggered saccades to peripheral targets either with the fixation stimulus remaining on (overlap trials) or going off before target onset (gap trials). All subjects showed faster reaction times in the gap trials (the gap effect). High density scalp event-related potentials were recorded time-locked to both the target stimuli and the eye movement onset. We observed three neural correlates of the gap effect: (i) a prefrontal positivity that precedes the target presentation which may reflect specific preparatory processes, (ii) an enhancement of the early cortical visual responses (PI) to the peripheral target in the gap trials, and (iii) a prolongation of parietal activity in the overlap trials relative to the gap trials prior to the saccade execution. These results suggest that several factors contribute to the gap effect, each having its own neural basis.

Cortical development and saccade planning: the ontogeny of the spike potential.

The spike potential is a sharply timed positivity which precedes eye movements in adults, and is thought to indicate cortical planning of saccades. While the spike potential is observed under most conditions in adults, it has not been reported in young infants. In the present study we shed light on the ontogeny of the spike potential by demonstrating for the first time its existence in a group of older infants (12 months). This result is consistent with a relatively delayed onset of cortical control over saccades during development.

Recording and analyzing high-density event-related potentials with infants. Using the Geodesic sensor net.

This article provides an overview of the use of the Geodesic sensor net system for high-density event-related potential (ERP) recording in infants. Some advantages and disadvantages of the system, as applied to infants, are discussed. First, we illustrate that high-density data can be recorded from infants at comparable quality to that observed with conventional (low density) ERP methods. Second, we discuss ways to utilize the greater spatial information available by applying source separation and localization procedures. In particular, we focus on the application of one recent source separation method, Independent Component Analysis (ICA). Finally, we show that source localization can be applied to infant high-density data, although this entails adopting a number of assumptions that remain to be verified. In the future, with improved source separation algorithms, we suggest that single-trial or single-subject analyses may become feasible.

Diet composition related to body fat in a multivariate study of 203 men.

OBJECTIVE: To assess whether usual diet (especially intake of dietary fat, carbohydrate, and fiber) was related to body fat percentage in healthy men. DESIGN: A written questionnaire provided data on demographic and lifestyle characteristics. Dietary fat, carbohydrate, protein, and fiber intakes were analyzed using the National Cancer Institute food frequency questionnaire. Percentage of body fat was determined using three-site skinfold measurements, and a submaximal treadmill test was used to estimate aerobic fitness. SUBJECTS: Subjects were 203 healthy men (14.0 +/- 5.3% mean body fat) aged 21 to 71 years. The subjects were chosen from randomly selected districts within Utah County and volunteered for free diet and fitness evaluations. STATISTICAL ANALYSIS: Multiple regression analysis determined the extent to which the individual diet components predicted body composition before and after controlling for energy intake, fitness level, body weight, and age. Multivariate analysis of variance was used to compare relative body fat groups in regard to dietary variables. RESULTS: Reported intakes of carbohydrate (P = .0085, R2 = .022), complex carbohydrate (P = .0127, R2 = .024), and fiber (P = .002, R2 = .03) were inversely associated with body fat after controlling for age, energy intake, and fitness level. Energy intake was positively related to body fat after controlling for age, fitness level, and body weight. When subjects were separated into low-, moderate-, and high-body-fat groups, the fattest subjects reported eating significantly more dietary fat (P = .05) and less carbohydrate (P = .01), complex carbohydrate (P = .01), and fiber (P = .005) than the leanest subjects. No significant difference in reported energy intake was noted across body fat groups. APPLICATIONS: Composition of the diet may play a role in obesity beyond energy intake in men over the long-term. Lifestyle changes for men should probably include modifications in diet composition, especially increased consumption of foods high in complex carbohydrate and fiber.

Body fat percentage of children varies according to their diet composition.

OBJECTIVE: To ascertain the association between diet composition and body fat percentage in 9- and 10-year-old children. Also, to examine the influence of gender, total energy intake, fitness, physical activity, and parental body mass on the relationship between diet composition and adiposity. DESIGN: Diet composition was assessed using the National Cancer Institute food frequency questionnaire, and adiposity was measured using the average of results determined using two skinfold equations. Fitness levels and physical activity were ascertained using the 1-mile run/walk test and a self-report 15-item scale, respectively. SUBJECTS: A sample of 262 children (162 boys and 100 girls, mean age = 9.8 +/- 0.5 years) participated. STATISTICAL ANALYSIS: Regression analysis was used to determine the extent to which diet composition contributed to adiposity without statistical control for any potentially confounding variables. Partial correlations were calculated to assess the relationship between macronutrient intake and adiposity after potential confounders (gender, total energy intake, physical fitness, and parental body mass) were controlled statistically. RESULTS: Energy intake was positively related to adiposity. Fat intake, calculated as a percentage of total energy, was also positively related to adiposity, before and after control for potential confounding variables. Percentage of energy derived from carbohydrate was inversely related to adiposity, before and after controlling for potential confounders. APPLICATIONS: These findings indicate that the macronutrient intake of children, particularly dietary fat and carbohydrate intake, may play a role in adiposity, independent of the influence of total energy intake, gender, physical fitness, and parental body mass index.

Neural correlates of saccade planning in infants: a high-density ERP study.

Neural correlates of saccade planning in 6-month-old infants were investigated by high-density event-related potentials. Subjects made saccades to a target stimulus following a time gap from fixation stimulus offset (gap trials) or with the fixation stimulus still present (overlap trials). Like adults, infants were slower to make a saccade to the target when the fixation stimulus was still present. Strikingly, infants did not show clear evidence of the pre-saccadic components observed in adults which are thought to reflect cortical saccade planning processes. They did, however, show a left frontal positivity, which we suggest reflects cortical disinhibition of the colliculus initiated by fixation stimulus offset, and clear post-saccadic lambda waves. These results indicate that the frontal cortex already plays a role in action control by 6 months of age, while other aspects of cortical action planning may not yet be present in certain task situations.

The relation between aerobic fitness and serum cholesterol levels in a large employed population.

BACKGROUND: The purpose of this epidemiologic study was to determine the extent to which aerobic fitness was associated with total cholesterol/HDL-C ratios greater than 5.0 in 10,455 adults. The confounding effects of age, gender, income, body fat, smoking, and alcohol use were also examined. METHODS: A step test was used to estimate aerobic fitness, and serum cholesterol was measured in a certified lab. Lifestyle information was gathered using written questionnaires, and body fat was assessed using skinfold measurements. RESULTS: High fitness levels were associated with low prevalence of elevated total/HDL-C ratios. After controlling for the potential confounders, adults classified as having excellent, very good, good, or fair aerobic fitness levels were .46, .64, .61, and .85 times as likely to have elevated ratios compared to poorly fit adults, respectively. High-level fitness was also related to high HDL-C levels and low total cholesterol levels. DISCUSSION: Cause-and-effect conclusions are not warranted; however, poorly fit adults appear to be at increased risk of elevated levels of serum cholesterol.

Effects of weight training on the emotional well-being and body image of females: predictors of greatest benefit.

BACKGROUND: This study was conducted to determine the extent to which participation in a weight training intervention was associated with changes in the emotional well-being and body image of females compared to non-weight trainers. An ancillary objective was to study the extent to which psychological, physical, and demographic factors accounted for changes in emotional well-being and body image. METHODS: The experimental group consisted of 60 females, and a comparison group was comprised of 92 females. Experimental subjects participated in a 15-week, two-day-per-week weight training intervention, while subjects in the comparison group did not participate in any weight training activities. Subjects were pre- and posttested on the General Well-Being Schedule and the Body Cathexis Scale. Experimental subjects were also tested in muscular strength and three skinfold measurements. RESULTS: With pretest scores controlled, the weight trainers had significantly higher General Well-Being and Body Cathexis posttest scores than the comparison group. Weight trainers also showed significant increases in muscular strength, and significant decreases in skinfold thickness. Four variables predicted 38.8% of the variance of those who improved most in General Well-Being: lower pretest General Well-Being, lower parental income, greater loss of body weight, and lower posttest skinfold. Five variables predicted 61.5% of the variance of those women who improved most in Body Cathexis: lower pretest Body Cathexis, greater body weight at the outset, shorter in height, less involvement in non-weight training exercise, and lower posttest skinfold. DISCUSSION: (ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between serum cholesterol levels and television viewing in 11,947 employed adults.

PURPOSE: The purpose of this study was to determine the prevalence of hypercholesterolemia among high-, moderate-, and low-duration television viewers. The confounding effects of age, gender, income, body fat percentage, weekly exercise duration, and smoking were also examined. DESIGN: A cross-sectional or correlational design was employed. Cochran-Mantel-Haenszel odds ratios were used to estimate risk of the television viewers regarding hypercholesterolemia. SETTING: Participants were employees of over 55 corporations that had their employees screened as part of the ongoing risk-management program of Health Advancement Services (HAS), Inc. SUBJECTS: Subjects were 11,947 employed adults. About 85% of the subjects eligible for participation completed the screenings and were used in the study. MEASURES: Serum cholesterol was assessed in a certified lab, and lifestyle information, including television viewing habits, was collected via a written questionnaire. Body fat was measured using skinfolds from three body sites. RESULTS: High-duration television viewers were almost two times more likely to suffer from hypercholesterolemia as infrequent viewers, with and without control of multiple confounding factors. Moderate-duration viewers were at 1.5 times the risk of hypercholesterolemia compared to infrequent viewers. Neither television group was at greater risk of moderately elevated cholesterol levels (200-239) compared to the infrequent viewers with all of the potential confounders controlled. CONCLUSIONS: Cause-and-effect conclusions are not warranted; however, this study coupled with other investigations shows that excessive television viewing may be an important lifestyle factor linked to decreased health and functioning.

Strength training and hypercholesterolemia: an epidemiologic study of 8499 employed men.

PURPOSE: This study was conducted to determine the relation between the quantity of strength training and hypercholesterolemia (total cholesterol > or = 240 mg/dl) in men. A secondary objective was to ascertain the effects of age, smoking, alcohol use, body mass, and participation in physical activities other than strength training on the association between strength training and hypercholesterolemia. DESIGN: A cross-sectional research design was used. SETTING: Data were collected at the worksites of subjects throughout the United States. SUBJECTS: The participants were 8499 male employees of more than 50 companies. MEASURES: Blood was drawn while the subjects were in a fasting state, and a questionnaire was used to collect the demographic and lifestyle information, including the data about strength training. The subjects were divided into five groups according to their self-reported duration and frequency (i.e., quantity) of participation in strength training. RESULTS: Subjects who reported regular involvement in strength training had a reduced risk of hypercholesterolemia. However, after controlling for all the potential confounders, only the high-quantity lifters, those who completed 4 to 7 hours of strength training each week, maintained a reduced risk of hypercholesterolemia. CONCLUSIONS: High-quality strength training is strongly associated with a reduced risk of hypercholesterolemia, even after controlling for numerous, potentially confounding factors (odds ratio = .46; 95% confidence interval = .23 to .91).

Comparison of the effects of walking and weight training programs on body image in middle-aged women: an experimental study.

Purpose. This study was conducted to determine the effect of a resistive training intervention on body image in middle-aged women compared to an exercise walking program. Another purpose was to develop two multivariate models to explain improvement in body image among the lifters and walkers. Design. A pretest-posttest experimental design with random assignment of subjects to two exercise groups was employed. Setting. Subjects trained in their own homes and were tested at the university. Subjects. Participants were 60 women recruited from the local community with an average age of 42.5 +/- 4.2 years. Intervention. Subjects were randomly assigned to a resistive training or exercise walking program, both of which were three days per week and 12 weeks in duration. Measures. Body cathexis was assessed using the Body Cathexis Scale; cardiovascular endurance was measured using the one-mile walk test, and muscular strength was assessed using standard weight training procedures. Results. After completion of the exercise interventions, lifters showed greater muscular strength than walkers, and walkers displayed greater cardiorespiratory endurance than lifters, as expected. Lifters also improved significantly more in body image than the walkers. Conclusions. Participation in a three-day-per-week resistive training program seems to improve body image in middle-aged women more than participation in a three-day per week walking program. Further, it appears that hard work and fitness improvements contribute significantly toward positive changes in body image.

Obesity and absenteeism: an epidemiologic study of 10,825 employed adults.

PURPOSE: This study was conducted to determine the extent of the relationship between obesity and absenteeism due to illness. A secondary objective was to ascertain the extent to which age, gender, family income, length of workweek, and cigarette smoking influenced the obesity-absenteeism association. DESIGN: A cross-sectional design was used. Data regarding obesity, absenteeism, and the potential confounding factors were collected during the same time period. SETTING: Data were collected within workplaces throughout the U.S., and at the headquarters of Health Advancement Services, Inc. (HAS). SUBJECTS: Subjects were 10,825 employed men and women who participated in an ongoing wellness screening program administered by HAS. MEASURES: The three-site skinfold technique was used to estimate body fat percentage. Absenteeism due to illness and the potential confounding variables were assessed using a structured paper-pencil questionnaire. RESULTS: Without controlling for any potential confounders, obese employees were more than twice as likely to experience high-level absenteeism (seven or more absences due to illness during the past 6 months), and 1.49 times more likely to suffer from moderate absenteeism (three to six absences due to illness during the last 6 months) than were lean employees. With all of the potential confounders controlled simultaneously, obese employees were 1.74 and 1.61 times more likely to experience high and moderate levels of absenteeism, respectively, than were lean individuals. CONCLUSIONS: Obese employees tend to be absent from work due to illness substantially more than their counterparts.

The effects of a single bout of strength training on ambulatory blood pressure levels in 24 mildly hypertensive men.

Twenty-four mildly hypertensive sedentary men were randomly assigned to one or two control conditions of health education or a treatment of a single bout of strength training. The men were rotated through the conditions until each man had participated in the treatment and both control conditions. Blood pressure was measured every 15 minutes for the 24-hour period following participation in each condition using an ambulatory blood pressure monitoring system. Compared to the control conditions, systolic blood pressure and blood pressure load were reduced for at least 1 hour after exercise, and diastolic blood pressure and blood pressure load were reduced for at least 3 minutes and 1 hour, respectively, after exercise.

Cardiovascular fitness and absenteeism in 8,301 employed adults.

Abstract The purpose of this study was to determine the extent of the relationship between cardiovascular fitness and absenteeism in the workplace. A total of 8,301 adult males and females who were employed by corporations which participated in a health screening program were used in the study. Absenteeism due to illness, demographic variables, and smoking status were assessed using a written questionnaire, while body fat was measured using skinfold calipers and cardiovascular fitness was assessed using a step test. Results indicated that high levels of cardiovascular fitness were associated significantly with low levels of absenteeism. The relationship remained strong after adjusting for differences in age, gender, income, cigarette smoking, and percent body fat. The association was stronger in females than males.

A prediction equation for estimating body fat percentage using readily accessible measures: a multivariate study of 200 adult women.

PURPOSE: This study was conducted to develop a regression equation that accurately estimates body fat percentage using relatively easy and inexpensive methods that do not require women to remove clothing. DESIGN: A cross-sectional design was employed. SETTING: All data were collected at the University. SUBJECTS: Subjects were 200 white women ages 20 to 65 years. The sample was equally distributed across four age groups, 20-29, 30-39, 40-49, and 50-65, and within each age group, one-third of the women were lean, one-third were of average weight, and one-third were obese. MEASURES: Subjects were hydrostatically weighed and participated in a variety of anthropometric and lifestyle assessments, including skinfolds, circumferences, and questionnaire responses. RESULTS: The full regression model included six measures: hip circumference, triceps skinfold (observed and quadratic), age (quadratic), self-reported physical activity, and calf skinfold (quadratic). This equation accounted for 81% of the variance in body weight measured by hydrostatic weighing (SEE = 3.5%). A simpler, five-variable equation was also formed that did not include the calf skinfold assessment (R2 = .800, SEE = 3.6%). CONCLUSIONS: The prediction equations in this study afford accurate and relatively easy and inexpensive means of estimating body fat percentage in a wide range of white women without having them remove their clothing.

Using simple measures to estimate body fat percentage in college men.

OBJECTIVE: To develop a prediction equation to estimate the body fat percentage of young men using simple measurements. METHODS: Subjects were 150 males, age 18 to 26 years. Self-reported lifestyle variables and measured circumferences were used to predict body fat percentage, assessed using hydrostatic weighing. RESULTS: The final model included 7 variables. The equation had a SEE of 2.66% and a PRESS SEE of 2.82%, and accounted for 80% of the variance in the criterion, body fat percentage. CONCLUSIONS: The regression equation developed in this study accurately estimates body fat percentage in young men by using simple, inexpensive measures.

Physical, psychological, social, and lifestyle differences among adolescents classified according to cigarette smoking intention status.

This study was conducted to determine the extent to which multiple physical, psychological, social, and lifestyle measures differ among high school males classified according to cigarette smoking intention status including nonintenders, mild intenders, and strong intenders. The Physical Performance Test for California, to measure six traits of physical fitness and Cattell's 16PF Questionnaire to assess manifold dimensions of personality were administered to 386 high school males. Self-concept was measured by Rosenberg's Self-esteem Scale and body build was assessed using Tucker's Perceived Somatotype Scale and the Body Mass Index. Data relative to marital status of parents, exercise experience, church attendance, participation in athletics, alcohol drinking habits, television viewing behavior, intention to attend college, dating behavior, as well as general demographic information and intention to smoke cigarettes were assessed by a written questionnaire. Results indicated that nonintenders were significantly more self-confident, intelligent, emotionally stable, moralistic, conservative, group oriented, self-controlled, relaxed, and more likely to respond in a socially desirable manner than were strong intenders. Nonintenders reported less dating, less television viewing, less alcohol consumption, and perceived themselves as and were determined to be less obese than strong intenders. Nonintenders also reported greater intentions to attend college, greater varsity athletic participation, were more likely to be residing with their natural mothers, and were more physically fit than were strong intenders. Possible health education and youth smoking prevention strategies are discussed.