Non-exercise physical activity (NEPA) is an important part of energy expenditure. This study aimed to investigate the prevalence of exercise and NEPA among adolescents. In the HKSOS project 2006-2007, the proportions of Hong Kong Chinese adolescents (N = 32,005) achieving 60-minute exercise and 60-minute NEPA per day were analyzed. Exercise was defined as structured and planned physical activities, and NEPA was defined as unstructured and unplanned physical activities including walking for transportation and climbing stairs. The prevalence of exercise was higher in boys than girls (after school: 63.8% vs 39.6%; holidays: 78.7% vs 60.0%), but the prevalence of NEPA in boys was similar to that in girls (after school: 72.2% vs 68.0%; holidays: 80.3% vs 79.4%). In general, the prevalence of both exercise and NEPA decreased with age in boys and girls, but was more marked for exercise than NEPA. In conclusion, the prevalence of exercise was lower in adolescent girls than boys, and decreased more rapidly with age than NEPA. NEPA seems to be easier to accumulate than exercise among adolescents regardless of sex and age.
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http://dx.doi.org/10.1186/1479-5868-8-3]

Objective. The reliability and validity of Stunkard's Figure Rating Scale (FRS) as a measure of current body size (CBS) was established in Western adolescent girls but not in non-Western population. We examined the validity and test-retest reliability of Stunkard's FRS in assessing CBS among Chinese adolescents. Methods. In a school-based survey in Hong Kong, 5666 adolescents (boys: 45.1%; mean age 14.7 years) provided data on self-reported height and weight, CBS, perceived weight status, and health-related quality of life using the Medical Outcomes Study Short-Form version 2 (SF-12v2). Height and weight were also objectively measured. Spearman's correlation was used to assess construct validity, concurrent validity and test-retest reliability.
Results. Convergent and discriminant validity were good: CBS correlated strongly with weight and self-reported/measured BMI, but only weakly with SF-12v2. CBS correlated strongly with perceived weight status, showing concurrent validity. Spearman's correlation (r) for CBS was 0.78 for girls and 0.72 for boys indicating good test-retest reliability. Validity and reliability results did not differ significantly between senior and junior grade adolescents. Conclusion. Our findings support the use of Stunkard's FRS to measure body size among Chinese adolescents.
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http://dx.doi.org/10.3109/17477166.2011.575146]

Objective. To investigate the association between weight misperception and psychosocial health problems among normal weight Chinese adolescent boys and girls.
Methods. In the Youth Smoking Survey 2003-04, 20 677 normal weight students aged 11-18 years from 85 randomly selected schools throughout Hong Kong were analysed. Students who perceived themselves as very thin, thin, fat or very fat were classified as having weight misperception in contrast to the reference group who correctly perceived themselves as normal weight. Psychosocial health outcomes included headache, feeling stressful, feeling depressed, poorer appetite, sleepless at night, having nightmares and less confidence in getting along with friends. Logistic regression yielded adjusted odds ratios (ORs) for each outcome by weight misperception in boys and girls separately.
Results. In girls, misperceived fatness was associated with all outcomes, while misperceived thinness was associated with poorer appetite and less confidence. Boys who misperceived themselves as very thin or fat had greater odds of all outcomes except having nightmares. In general, greater ORs were observed for misperceived fatness than thinness in girls, but similar ORs were observed in boys. Misperceived thinness and fatness accounted for 0.6% to 45.1% of the psychosocial health problems in adolescents.
Conclusions. Normal weight adolescents with weight misperception were more likely to have psychosocial health problems, and the associations were stronger for extreme misperceptions (i.e., very fat or very thin) in both boys and girls.
[Copyright of International Journal of Pediatric Obesity is the property of Informa Healthcare. Full article may be available at the publisher's website:
http://dx.doi.org/10.3109/17477166.2010.514342]

Background: This study was designed to investigate the relation between health-related physical fitness and weight status in Hong Kong adolescents. Methods: 3,204 students aged 12-18 years participated in the Hong Kong Student Obesity Surveillance (HKSOS) project in 2006-2007. Anthropometric measures (height, weight) and health-related fitness (push-up, sit-up, sit-andreach, 9-minute run) were assessed. Body mass index (BMI) was computed to classify participants into normal weight, underweight (Grade I, II/III), overweight, and obese groups. The associations of health-related physical fitness with BMI and weight status were examined by partial correlation coefficients and analysis of covariance, respectively. Results: More boys than girls were overweight or obese (18.0% vs 8.7%), but more girls than boys were underweight (22.3% vs 16.7%). Boys performed significantly (P < 0.001) better in sit-up (38.8 vs 31.6 times/min) and 9-minute run (1632.1 vs 1353.2 m), but poorer in sit-and-reach (27.4 vs 32.2 cm) than girls. All four physical fitness tests were significantly positively correlated with each other in both sexes, and BMI was only weakly correlated with sit up and sit-and-reach tests in boys. Decreasing performance (P for trend < 0.05) was observed from normal weight to overweight and obese for push-up, sit-up, and 9-minute run in both sexes. From normal weight to Grade I and Grade II/III underweight, decreasing performance (P for trend < 0.05) for sit-up and sit-and-reach in both sexes and for push-up in boys was observed. Conclusions: The relations between BMI and health-related physical fitness in adolescents were non-linear. Overweight/obese and underweight adolescents had poorer performance in push-up and sit-up tests than normal weight adolescents. Different aspects of health-related physical fitness may serve as immediate indicators of potential health risks for underweight and overweight adolescents.
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