Effects of aerobic and resistance training on abdominal fat, apolipoproteins and high-sensitivity C-reactive protein in adolescents with obesity: the HEARTY randomized clinical trial.

OBJECTIVES: To investigate the effects of aerobic training, resistance training, or both on abdominal subcutaneous fat (subcutaneous adipose tissue (SAT)) (deep and superficial), visceral fat (visceral adipose tissue (VAT)), apolipoproteins A-1 and B (ApoA-1, ApoB), ApoB/ApoA-1 ratio and high-sensitivity C-reactive protein (HSCRP) in post-pubertal adolescents with obesity. PARTICIPANTS: After a 4-week supervised moderate-intensity exercise run-in period, 304 postpubertal adolescents with overweight (body mass index (BMI) ⩾85th percentile for age and sex+diabetes risk factor) or obesity (⩾95th BMI percentile) aged 14-18 years were randomized to four groups for 22 weeks (5 months): aerobic training, resistance training, combined training or a non-exercising control. METHODS: This study used a randomized controlled design. All groups received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of 250 kcal. Abdominal fat (SAT and VAT) at the level of the fourth and fifth lumbar vertebrae (L4-L5) was measured by magnetic resonance imaging and ApoA-1, ApoB and HSCRP were measured after a 12-h fast at baseline and after 6 months. RESULTS: Changes in SAT at L4-L5 were -16.2 cm(2) in aerobic (P=0.04 vs control), -22.7 cm(2) in resistance (P=0.009 vs control) and -18.7 cm(2) in combined (P=0.02 vs control). Combined training reduced ApoB levels from 0.81±0.02 to 0.78±0.02 g l(-1) (P=0.04 vs control) and ApoB/ApoA-1 ratio from 0.67±0.02 to 0.64±0.02 (P=0.02 vs control and P=0.04 vs aerobic). There were no significant differences in VAT, ApoA-1 or HSCRP levels between groups. CONCLUSIONS: Aerobic and resistance training and their combination decreased abdominal SAT in adolescents with obesity. Combined training caused greater improvements in ApoB/ApoA-1 ratio compared with aerobic training alone.

Edmonton Obesity Staging System for Pediatrics, quality of life and fitness in adolescents with obesity.

BACKGROUND: Body mass index (BMI) is often used to diagnose obesity in childhood and adolescence but has limitations as an index of obesity-related morbidity. The Edmonton Obesity Staging System for Pediatrics (EOSS-P) is a clinical staging system that uses weight-related comorbidities to determine health risk in paediatric populations. The purpose of this study was to investigate the associations of EOSS-P and BMI percentile with quality of life (QOL), cardiorespiratory fitness (CRF) and muscular strength in adolescents with obesity. METHODS: Participants were enrolled at baseline in the Healthy Eating, Aerobic and Resistance Training in Youth trial (BMI = 34.6 ± 4.5 kg m-2, age = 15.6 ± 1.4 years, N = 299). QOL, CRF (peak oxygen uptake, VO2peak) and muscular strength were assessed by the Pediatric QOL Inventory (PedsQL), indirect calorimetry during a maximal treadmill test and eight-repetition maximum bench and leg press tests, respectively. Participants were staged from 0 to 3 (absent to severe health risk) according to EOSS-P. Associations were assessed using age-adjusted and sex-adjusted general linear models. RESULTS: Quality of life decreased with increasing EOSS-P stages (p < 0.001). QOL was 75.7 ± 11.4 in stage 0/1, 69.1 ± 13.1 in stage 2 and 55.4 ± 13.0 in stage 3. BMI percentile was associated with VO2peak (ß = -0.044 mlO2 kg-1 min-1 per unit increase in BMI percentile, p < 0.001), bench press (ß = 0.832 kg per unit increase in BMI percentile, p = 0.029) and leg press (ß = 3.992 kg, p = 0.003). There were no significant differences in treadmill time or VO2peak between EOSS-P stages (p > 0.05). CONCLUSION: As EOSS-P stages increase, QOL decreases. BMI percentile was negatively associated with CRF and positively associated with muscular strength.

Understanding low adherence to an exercise program for adolescents with obesity: the HEARTY trial.

INTRODUCTION: Despite efforts to improve adherence to physical activity interventions in youth with obesity, low adherence and attrition remain areas of great concern. OBJECTIVE: The study was designed to determine which physiological and/or psychological factors predicted low adherence in adolescents with obesity enrolled in a 6-month exercise intervention study aimed to improve body composition. METHODS: Three hundred four adolescents with obesity aged 14-18 years who volunteered for the HEARTY (Healthy Eating Aerobic and Resistance Training in Youth) randomized controlled trial completed physiological (body mass index, waist circumference, per cent body fat, resting metabolic rate and aerobic fitness) and psychological (body image, mood, self-esteem and self-efficacy) measures. RESULTS: One hundred forty-one out of 228 (62%) randomized to exercise groups had low adherence (completed <70% of the prescribed four exercise sessions per week) to the intervention protocol. Logistic regression revealed that there were no baseline demographic or physiological variables that predicted low adherence in the participants. Appearance concern (a subscale of body image) (odds ratio [OR] 1.46, 95% confidence interval [CI]: 1.01, 2.1, P = 0.04), depressive mood (OR 1.12, 95% CI: 1.01, 1.23, P = 0.03) and confused mood (OR 1.16, 95% CI: 1.05, 1.27, P = 0.003) (two subscales of mood) were significant predictors of low adherence. CONCLUSIONS: Adolescents with obesity who had higher appearance concerns and depressive and confused moods were less likely to adhere to exercise. Body image and mood should be screened to identify adolescents who may be at high risk of poor adherence and who may need concurrent or treatment support to address these psychological issues to derive maximal health benefits from an exercise programme.

Validity of foot-to-foot bioelectrical impedance analysis in overweight and obese children and parents.

AIM: The aim of this study was to evaluate the validity of foot-to-foot bioelectrical impedance analysis (FF-BIA) in the measurement of body composition in overweight and obese children and their parents by comparison to dual-energy X-ray absorptiometry (DXA). METHODS: Seventeen, 7-12 year old overweight and obese children (6 boys, 11 girls) and 17 parents (5 fathers, 12 mothers) were evaluated for body composition with FF-BIA and DXA. Measures of percent body fat (PBF), fat mass (FM) and fat free mass (FFM) derived from FF-BIA and DXA were compared. Measures of validity were determined by Pearson correlations between FF-BIA and DXA, paired t-tests to assess mean differences, as well as biases and limits of agreement using the Bland Altman tests. RESULTS: FF-BIA produced estimates of body composition that were highly correlated with DXA in overweight and obese children and parents. For children, the correlations for PBF, FM, and FFM were 0.85, 0.97, and 0.94, respectively. For parents, the correlations for PBF, FM, and FFM were 0.92, 0.97, and 0.91, respectively. However, mean differences between FF-BIA and DXA were significant in children but not in parents. Bland-Altman tests of agreement showed moderate to large within-subject differences in body composition variables between FF-BIA and DXA. CONCLUSIONS: FF-BIA is strongly related to DXA in the measurement of body composition in both overweight and obese preadolescent children and parents, but the two measures may not be used interchangeably. Although FF-BIA may lack the precision to assess small changes in body composition in overweight and obese individuals, it is appropriate for epidemiological use.

Physical activity in the treatment of childhood overweight and obesity: current evidence and research issues.

PURPOSE: This paper reviews the utility of exercise as a treatment for overweight and obese children and adolescents. METHODS: Computer database searches identified 13 studies that met the following criteria for inclusion: 1) obese children or adolescents were provided either different types of exercise programs or an exercise program compared with a no-exercise control, 2) subjects were randomly assigned to groups or assigned by matching on demographic and anthropometric variables, and 3) the exercise program was at least 2 months in duration. RESULTS: The only area in which there were a sufficient number of studies to make a quantitative analysis was the comparison of diet versus diet plus exercise programs, which suggested that exercise adds to the effect of diet in the short-term treatment of pediatric obesity. There was not enough research to evaluate the effects of exercise alone. The majority of findings indicate fitness changes are greater for subjects provided exercise alone or exercise combined with diet in comparison with subjects provided no exercise (control) or diet alone. CONCLUSIONS: Research on effects of exercise or physical activity in pediatric obesity treatments are encouraging and may be important for improving treatment outcome for obesity and comorbid conditions. Recommendations for future research are presented.

Is energy intake altered by a 10-week aerobic exercise intervention in obese adolescents?

AIM: To examine energy intake adaptations to a 10-week aerobic exercise program in obese adolescents. METHODS: Twenty-six 12-17year old obese adolescents were asked to cycle twice a week for an hour in a research laboratory. Body composition, aerobic fitness (submaximal fitness test) and energy intake (3-day food record) were assessed before and immediately after the 10-week intervention. RESULTS: The average time spent pedaling per session was 55.3±12.1min for a mean energy expenditure of 2196±561kJpersession. The intervention produced significant improvements in percentage of body fat (44.5±10.6% vs. 43.4±9.8%; p<0.05) but no significant weight and fat-free mass change. Peak workload (79.5±20.8W vs. 87.3±17.6W; p<0.05) and peak heart rate (174.6±18.7bpm vs. 166.2±21.0bpm; p<0.01) were improved. The mean total daily energy intake (in kJ/day) showed a tendency to decrease through the intervention (7440±1744 to 6740±2124kJ; p=0.07) but a high inter-individual variability observed in the energy intake response to the intervention may explain the non-significant association between the energy intake response and weight loss. CONCLUSION: A 10-week aerobic exercise program may result in a small decrease in energy intake and an associated decrease in percentage of body fat but no weight loss in obese adolescents. This lack of weight loss could be explained by a decrease in spontaneous energy expenditure outside the intervention sessions.

Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY): study rationale, design and methods.

PURPOSE: The objective of the Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) trial (ClinicalTrials.Gov # NCT00195858) was to examine the effects of resistance training, with and without aerobic training, on percent body fat in sedentary, post-pubertal overweight or obese adolescents aged 14-18 years. This paper describes the HEARTY study rationale, design and methods. METHODS: After a 4-week supervised low-intensity exercise run-in period, 304 overweight or obese adolescents with a body mass index≥85th percentile for age and sex were randomized to 4 groups for 22 weeks (5 months): diet+aerobic exercise, diet+resistance exercise, diet+combined aerobic and resistance exercise, or a diet only waiting-list control. All participants received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of -250 kcal. OUTCOMES: The primary outcome is percent body fat measured by Magnetic Resonance Imaging. Secondary outcomes include changes in anthropometry, regional body composition, resting energy expenditure, cardiorespiratory fitness, musculoskeletal fitness, cardiometabolic risk markers, and psychological health. SUMMARY: To our knowledge, HEARTY is the largest clinical trial examining effects of aerobic training, resistance training, and combined aerobic and resistance training on changes in adiposity and cardiometabolic risk markers in overweight and obese adolescents. The findings will have important clinical implications regarding the role that resistance training should play in the management of adolescent obesity and its co-morbidities.

Body image and steroid use in male bodybuilders.

This study was designed to examine the association between body image and eating-related attitudes among male bodybuilders in relation to two athletic comparison groups, runners and martial artists. It was also of interest to examine whether steroid use may be associated with body image disturbances in athletes. The volunteer sample of 139 male athletes recruited from fitness centers comprised 43 bodybuilders, 48 runners, and 48 martial artists (tae kwon do practitioners). Standardized measures of body dissatisfaction, drive for thinness, drive for bulk, bulimia, self-esteem, depression, maturity fears, and perfectionism as well as questionnaires designed to measure attitudes toward steroids, and rates of steroid use were administered in a manner that encouraged disclosure. Bodybuilders reported significantly greater body dissatisfaction, with a high drive for bulk, high drive for thinness, and increased bulimic tendencies than either of the other athletic groups. In addition bodybuilders reported significant elevations on measures of perfectionism, ineffectiveness, and lower self-esteem. They also reported the greatest use of anabolic steroids and most liberal attitudes towards using steroids. Steroid users reported that the most significant reason for using steroids was to improve looks. Steroid users reported an elevated drive to put on muscle mass in the form of bulk, greater maturity fears, and enhanced bulimic tendencies than nonusers. The results suggest that male bodybuilders are at risk for body image disturbance and the associated psychological characteristics that have been commonly reported among eating disorder patients. These psychological characteristics also appear to predict steroid use in this group of males.

Open-loop feedback to increase physical activity in obese children.

OBJECTIVE: The present study investigated whether making access to sedentary activities contingent on physical activity would increase physical activity. DESIGN: Experimental. PARTICIPANTS: Thirty-four obese children aged 8-12 y were randomized to one of three groups in which children had to accumulate 750 or 1500 pedometer counts to earn 10 min of access to video games or movies, or to a control group in which access to sedentary behaviors was provided noncontingently. MEASUREMENTS: Physical activity in the 20 min experimental session was measured by electronic pedometer and triaxial accelerometer (ie TriTrac(R)). Activity liking was measured by visual analog scales. Anthropometric and demographic characteristics were also assessed. RESULTS: Children in the 750 and 1500 count contingency groups engaged in significantly more physical activity and spent more time in moderate intensity activity or higher compared with controls. Children in the Contingent 1500 group engaged in more activity and spent more time in moderate or greater intensity activity compared to children in the Contingent 750 group. CONCLUSION: Findings suggest that contingent access to sedentary activities can reinforce physical activity in obese children, and changes in physical activity level depend in part on the targeted physical activity goal.

Parental activity as a determinant of activity level and patterns of activity in obese children.

The purposes of this study were to measure the level and pattern of moderate-to-vigorous physical activity (MVPA = > 4.5 METs) and examine predictors of activity in obese children. Fifty-one 8-12-year-old children seeking obesity treatment wore accelerometers for 3 or 4 days. Children averaged 12.2 bouts of MVPA per day that lasted an average of 4.2 min, while parents engaged in 3.9 bouts of MVPA that lasted 4.2 min. Hierarchical regression models showed parent activity improved the prediction of obese children's activity levels and the number of bouts of MVPA but not the duration of MVPA. These results suggest that programs to increase physical activity in obese children should structure the activity in short bouts and attempt to increase parental physical activity.

Cost-effectiveness of group and mixed family-based treatment for childhood obesity.

OBJECTIVE: Family-based, behavioral treatment has been shown to be an effective intervention for the management of pediatric obesity. The goal of this study was to compare the cost-effectiveness of two protocols for the delivery of family-based behavioral treatment. RESEARCH METHODS AND PROCEDURES: Thirty-one families with obese children were randomized to groups in which families were provided mixed treatment incorporating both group and individualized treatment vs group treatment only. Cost-effectiveness of treatment was defined as the magnitude of reduction in standardized BMI and percentage overweight per dollar spent for recruitment and treatment. Anthropometric data were assessed at baseline, 6 months and 12 months post-randomization. RESULTS: Results for the 24 families with complete data showed the group intervention was significantly more cost-effective than the mixed treatment. This was due to the similarity between the two groups in Z-BMI or percentage overweight change for children and their parents, while the mixed treatment was significantly more expensive to deliver than the group treatment. DISCUSSION: These findings suggest that a family-based, behavioral intervention employing group treatment alone is a more cost-effective approach to treating pediatric obesity than a mixed group plus individual format.

How much activity do youth get? A quantitative review of heart-rate measured activity.

OBJECTIVE: Recommendations for adult physical activity have shifted from 20 to 60 minutes of continuous vigorous activity 3 to 5 times a week to accumulation of 30 minutes of moderate to vigorous physical activity most days of the week. Variations of these guidelines also have been suggested for children, based on the idea of accumulating moderate to vigorous physical activity throughout the day, rather than attaining vigorous physical activity in continuous blocks. The goal of this study was to assess accumulated amounts of physical activity at different intensities in children. METHODS: We reviewed 26 studies (n = 1883) in youth aged 3 to 17 years that used heart-rate recording to measure physical activity in children to determine accumulated daily activity. Included were studies that provided time being active for at least 2 heart rate intensities at or above 120 beats/minute. Descriptive characteristics of the study groups were determined, and the influence of age, gender, and hours and days of observation on the slope of activity time as a function of percentage of heart rate reserve (HRR) was determined using hierarchical linear regression. RESULTS: Youth attained 128.0 +/- 45.6, 47.1 +/- 14.9, 29.3 +/- 13.7, and 14.7 +/- 6.0 minutes/day between 20% to 40%, 40% to 50%, 50% to 60%, and greater than 60% HRR, respectively. Age was a significant predictor of the intercept and slope of the physical activity and %HRR relationship. CONCLUSION: Youth of all ages attain >60 minutes/day of low-intensity physical activity and approximately 30 minutes/day of activity at traditional cardiovascular fitness training levels of 50% or more of HRR. Recommendations for youth activity are discussed.