Cardiovascular fitness in obese versus nonobese 8-11-year-old boys and girls

The Effect of Body Mass Index on Acute Cardiometabolic Responses to Graded Exercise Testing in Children: A Narrative Review

Although the beneficial role of exercise for health is widely recognized, it is not clear to what extent the acute physiological responses (e.g., heart rate (HR) and oxygen uptake (VO₂)) to a graded exercise test are influenced by nutritional status (i.e., overweight vs. normal-weight). Therefore, the main objectives of the present narrative review were to examine the effect of nutritional status on acute HR, and VO₂ responses of children to exercise testing. For this purpose, we examined existing literature using PubMed, ISI, Scopus, and Google Scholar search engines. Compared with their normal-body mass index (BMI) peers, a trend of higher HRrest, higher HR during submaximal exercise testing, and lower HRmax was observed among overweight and obese children (according to BMI). Independent from exercise mode (walking, running, cycling, or stepping), exercise testing was metabolically more demanding (i.e., higher VO₂) for obese and overweight children than for their normal-weight peers. Considering these cardiometabolic differences according to BMI in children might help exercise specialists to evaluate the outcome of a graded exercise test (GXT) (e.g., VO2max, HRmax) and to prescribe optimal exercise intensity in the context of development of exercise programs for the management of body mass.

Gait Pattern, Impact to the Skeleton and Postural Balance in Overweight and Obese Children: A Review

The article reviews the biomechanical factors that may cause overweight/obese children to reduce their level of physical activity, while increasing their risk of overuse injuries and exercise-related pain. Recommendations would be to screen those children for any gait or postural impairments before they join any exercise program, and to provide them with specific gait treatments and/or physical exercise programs, in order to decrease their risk for future musculoskeletal injuries and pain.

A cross-sectional study to examine the association between dietary patterns and risk of overweight and obesity in Hong Kong Chinese adolescents aged 10-12 years

OBJECTIVE

To describe the dietary patterns and examine the associations of these patterns with risk of overweight and obesity in Chinese adolescents.

METHODS

Baseline data collected between November 2003 and October 2004 from 171 boys and 180 girls aged 10-12 years who participated in the Hong Kong Adolescent Bone Health Cohort Study were analyzed. Dietary intake was assessed using a food frequency questionnaire and dietary pattern calculated using factor analysis. Data on demographic characteristics, weight, height, and Tanner stage were collected. Overweight and obesity were defined using The International Obesity Task Force cutoff values. Cardiovascular fitness expressed as peak oxygen consumption was predicted using the postexercise heart rate by the 3-minute step test and was used as an objective measure of physical activity. Association between dietary patterns and risk of overweight and obesity was examined using multivariate logistic regression with adjustment for demographics, puberty, and physical activity.

RESULTS

The mean (SD) age of the study sample was 11.2 (0.6) years and there were 57 (16.2%) participants who were overweight/obese. Three dietary patterns were identified, namely, vegetables-fruits, snacks-beverages, and animal foods, fats, and condiments dominated. There was no significant linear association between each dietary pattern and the risk of overweight and obesity in this sample. Instead, the risk of overweight and obesity in this sample was positively associated with pubertal stage and inversely associated with physical activity.

CONCLUSIONS

Pubertal stage and physical activity, but not dietary patterns, were important factors contributing to the risk of overweight and obesity in this population.

Weight status, physical activity, and fitness among third-grade rural children

BACKGROUND

Rural children are at a particular high risk for obesity. Given the importance of exercise in obesity and chronic disease prevention, this study evaluated the level and relationship between physical activity and fitness in a sample of rural third graders. The second purpose of the study was to determine potential differences in physical activity and fitness level by weight status in this sample.

METHODS

Twelve schools participating in a multidisciplinary research project were randomly selected for the study. Body mass index-for-age percentile, the modified Self-administered Physical Activity Checklist, and the FITNESSGRAM battery tests were utilized to determine children's weight status, physical activity, and fitness level, respectively.

RESULTS

Thirty-eight percent of the 237 participating children (9.2 ± 0.4 years) were overweight or obese. Nearly 15% were extremely obese. Children spent 91.8 ± 83.8 and 32.2 ± 47.7 minutes in moderate- and vigorous-intensity activities. Obese children spent less time in moderate-intensity activity (p < .01) and combined moderate- and vigorous-intensity activity more than other children (p < .05). Forty-three percent of all children failed to meet the fitness standard for muscular strength and 36% failed to meet it for flexibility.

CONCLUSIONS

Rural children in this sample had higher rates of obesity compared to the national average; they had poor fitness and 30% failed to meet the minimum physical activity recommendations on the previous day. Future interventions should focus on increasing physical activity, especially of moderate-intensity, and improving physical fitness in order to reduce obesity and decrease the risk of future chronic diseases in this high-risk population.

Physical activity and obesity: biomechanical and physiological key concepts

Overweight (OW) and obesity (OB) are often associated with low levels of physical activity. Physical activity is recommended to reduce excess body weight, prevent body weight regain, and decrease the subsequent risks of developing metabolic and orthopedic conditions. However, the impact of OW and OB on motor function and daily living activities must be taken into account. OW and OB are associated with musculoskeletal structure changes, decreased mobility, modification of the gait pattern, and changes in the absolute and relative energy expenditures for a given activity. While changes in the gait pattern have been reported at the ankle, knee, and hip, modifications at the knee level might be the most challenging for articular integrity. This review of the literature combines concepts and aims to provide insights into the prescription of physical activity for this population. Topics covered include the repercussions of OW and OB on biomechanical and physiological responses associated with the musculoskeletal system and daily physical activity. Special attention is given to the effect of OW and OB in youth during postural (standing) and various locomotor (walking, running, and cycling) activities.