Intracranial Vascular Responses to High-Intensity Interval Exercise and Moderate-Intensity Steady-State Exercise in Children.

PURPOSE: To understand the extent different types of acute exercise influence cerebral blood flow during and following exercise in children. METHODS: Eight children (7-11 y; 4 girls) completed 2 conditions: high-intensity interval exercise (HIIE; 6 × 1-min sprints at 90% watt maximum) and moderate-intensity steady-state exercise (MISS; 15 min at 44% watt maximum). Blood velocity in the middle cerebral artery (MCAV) and heart rate were assessed continuously. The partial pressure of end-tidal carbon dioxide and mean arterial pressure were assessed at baseline and following exercise. RESULTS: Percentage of maximum heart rate during HIIE was 82% (4%), compared with 69% (4%) during MISS. MCAV was increased above baseline in MISS after 75 seconds (5.8% [3.9%], P × .004) but was unchanged during HIIE. MCAV was reduced below baseline (-10.7% [4.1%], P × .004) during the sixth sprint of HIIE. In both conditions, MCAV remained below baseline postexercise, but returned to baseline values 30-minute postexercise (P < .001). A postexercise increase in mean arterial pressure was apparent following HIIE and MISS, and persisted 30-minute postexercise. Partial pressure of end-tidal carbon dioxide declined post HIIE (-3.4 mm Hg, P < .05), but not following MISS. CONCLUSION: These preliminary findings show HIIE and MISS elicit differing intracranial vascular responses; however, research is needed to elucidate the implications and underlying regulatory mechanisms of these responses.

Mediating effects of body composition between physical activity and body esteem in Hong Kong adolescents: a structural equation modeling approach.

This study investigated the mediating role of body mass index (BMI) in the relationship between physical activity and body esteem in adolescents. Nine hundred and five Hong Kong Chinese students aged 12-18 years participated in a cross-sectional study in 2007. Students' BMI was computed as an indicator of their body composition. Their physical activity level and body esteem were examined using the Physical Activity Rating for Children and Youth (PARCY) and Body Esteem Scale (BES), respectively. Structural equation modelling was used to investigate the mediating effects of BMI and physical activity in predicting body esteem, with stratification by sex. The overall fit of the hypothesized models was satisfactory in boys (NFI = 0.94; NNFI = 0.88; CFI = 0.95; RMSEA = 0.07) and girls (NFI = 0.89; NNFI = 0.77; CFI = 0.91; RMSEA = 0.11). When BMI was considered as a mediator, higher physical activity had a significant negative total effect on body esteem in boys, but not in girls. The indirect effect of higher physical activity on body esteem via BMI was positive in boys, but negative in girls. CONCLUSIONS: Regular physical activity may help overweight adolescents, especially boys, improve their body esteem. Kinesiologists and health professionals could explore the use of physical activity prescriptions for weight management, aiming at body esteem improvement in community health programs for adolescents. WHAT IS KNOWN: Among Western adolescents, negative body esteem is more pervasive in girls than in boys. There are consistent findings of the association between higher body mass index and lower body esteem in adolescents, but the association between physical activity and body esteem are equivocal. WHAT IS NEW: A negative association between body mass index and body esteem was found in both Hong Kong adolescent boys and girls. The indirect effect of physical activity on body esteem via body mass index was positive in Hong Kong adolescent boys, but negative in girls.

Body size dissatisfaction among young Chinese children in Hong Kong: a cross-sectional study.

OBJECTIVE: To determine the potential predictors of body size dissatisfaction in Chinese children. DESIGN: The Child's Body Image Scale was used to assess body size perception and dissatisfaction. BMI was calculated from objectively measured height and weight. Predictors of body size dissatisfaction were examined by logistic regression analysis. SETTING: Hong Kong, China. SUBJECTS: Six hundred and twenty children (53 % boys, aged 6·1-12·9 years) from a state-run primary school. RESULTS: Female sex (adjusted OR (AOR)=1·91; 95 % CI 1·32, 2·76), age (AOR=2·62; 95 % CI 1·65, 4·16 for 8-10 years; AOR=2·16; 95 % CI 1·38, 3·38 for >10 years), overweight (AOR=6·23; 95 % CI 3·66, 10·60) and obesity (AOR=19·04; 95 % CI 5·64, 64·32) were positively associated with desire to be thinner. Size misperception was a strong predictor of body size dissatisfaction, irrespective of actual weight status (AOR=1·90; 95 % CI 1·02, 3·54 for overestimation; AOR=0·43; 95 % CI 0·27, 0·67 for underestimation). CONCLUSIONS: Body size dissatisfaction is prevalent among Chinese children as young as 6 years. Female sex, age, overweight, obesity and overestimation of size were associated with increased desire to be thinner. These findings emphasise the importance of preventing body image issues from an early age.

Muscle metabolism changes with age and maturation: How do they relate to youth sport performance?

AIM: To provide an evidence-based review of muscle metabolism changes with sex-, age- and maturation with reference to the development of youth sport performance. METHODS: A narrative review of data from both invasive and non-invasive studies, from 1970 to 2015, founded on personal databases supported with computer searches of PubMed and Google Scholar. RESULTS: Youth sport performance is underpinned by sex-, age- and maturation-related changes in muscle metabolism. Investigations of muscle size, structure and metabolism; substrate utilisation; pulmonary oxygen uptake kinetics; muscle phosphocreatine kinetics; peak anaerobic and aerobic performance; and fatigue resistance; determined using a range of conventional and emerging techniques present a consistent picture. Age-related changes have been consistently documented but specific and independent maturation-related effects on muscle metabolism during exercise have proved elusive to establish. Children are better equipped for exercise supported primarily by oxidative metabolism than by anaerobic metabolism. Sexual dimorphism is apparent in several physiological variables underpinning youth sport performance. As young people mature there is a progressive but asynchronous transition into an adult metabolic profile. CONCLUSIONS: The application of recent developments in technology to the laboratory study of the exercising child and adolescent has both supplemented existing knowledge and provided novel insights into developmental exercise physiology. A sound foundation of laboratory-based knowledge has been established but the lack of rigorously designed child-specific and sport-specific testing environments has clouded the interpretation of the data in real life situations. The primary challenge remains the translation of laboratory research into the optimisation of youth sports participation and performance.

Orlistat improves endothelial function in obese adolescents: a randomised trial.

AIM: To investigate the effect of orlistat on endothelial function in obese adolescents. METHODS: Single-blind 10-week controlled trial of 67 normolipidaemic obese adolescents randomised into three groups. Group 1 (diet alone), Group 2 (diet and orlistat), Group 3 (diet, orlistat and exercise). Endothelial function measured by flow-mediated dilatation (FMD) of the brachial artery, anthropometric parameters, blood pressure, fasting blood lipids, insulin and glucose levels were recorded at baseline and at 10 weeks. RESULTS: Sixty four subjects completed the study. Groups were comparable at baseline. FMD increased significantly with orlistat (Groups 2 and 3) but not in Group 1. Orlistat treatment resulted in significantly reduced bodyweight, body mass index (BMI), waist circumference, total and low-density lipoprotein (LDL) cholesterol levels. High-density lipoprotein cholesterol levels were unchanged. Triglyceride and insulin levels were significantly reduced in all three groups. The reduction in cholesterols did not correlate with reductions in weight and BMI. A slight reduction of body fat, both with and without orlistat treatment, correlated with reduction in BMI after adjustment for baseline values. Blood pressure was unaltered by orlistat. Calorie intake was reduced with orlistat, and the decrease noted in % fat and increase in % carbohydrate was significant only in those taking orlistat. The addition of exercise (Group 3 compared with Group 2) altered no parameter. CONCLUSIONS: Orlistat improves endothelial function and reduces bodyweight, BMI, fasting total and LDL-cholesterol in obese adolescents when combined with dietary control. Improvement in endothelial function if maintained could reflect long-term cardiovascular benefit.

Validity of self-estimated adiposity assessment against general and central adiposity in Hong Kong adolescents.

BACKGROUND AND AIM: The relationships between self-estimated adiposity using Stunkard's body silhouette scale with general and central adiposity in adolescents are unclear. This study examines the criterion validity of Stunkard's body silhouette scale as a self-estimated rating of adiposity against anthropometric measures of adiposity and percentage body fat in Hong Kong adolescents. SUBJECTS AND METHODS: The body composition of 903 adolescents (55.7% boys) was assessed by measured waist circumference (WC), waist-to-stature ratio (WSR), body mass index (BMI) and percentage body fat (%BF). Self-estimated adiposity was subjectively assessed using Stunkard's body silhouette scale. The association between self-estimated adiposity and body composition was examined by Spearman correlation coefficients and hierarchical multiple regression analyses. RESULTS: Self-estimated adiposity correlated significantly and positively with BMI (boys: r = 0.65; girls: r = 0.59), WC (boys: r = 0.62; girls: r = 0.51), WSR (boys: r = 0.55; girls: r = 0.42) and %BF (boys: r = 0.47; girls: r = 0.55). CONCLUSION: Self-estimated adiposity using the Stunkard's body silhouette scale was positively associated with actual measures of adiposity; however, the association was modest at best. It is unlikely that the Stunkard's body silhouette scale provides a suitably accurate substitute for actual body composition measures in Chinese adolescents.

Percentage body fat and anthropometric measures in Hong Kong adolescents.

This study investigates the associations between percentage body fat (%BF) and anthropometric parameters in adolescents of mixed weight status. Anthropometric parameters including height, weight, and waist circumference (WC), and %BF were assessed in 903 Hong Kong Chinese students (mean age 14.7 years). The calculated body mass index (BMI) and waist-to-stature ratio (WSR) were used to classify students into different weight status groups and central obesity groups, respectively. The %BF/BMI and %BF/WC relationships were examined by partial correlation coefficients and linear regression models. The %BF correlated significantly with BMI, except in underweight boys. BMI predicted %BF better (adjusted R (2): 0.40 in boys; 0.85 in girls) than WC (adjusted R (2): 0.34 in boys; 0.63 in girls) or WSR (adjusted R (2): 0.33 in boys; 0.60 in girls). In general, BMI predicts %BF better than WC or WSR in Hong Kong adolescents, but these relationships are sex and weight status specific.

Follow up of aerobic capacity in children affected by severe acute respiratory syndrome.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the aerobic capacity of children 3 years after they were diagnosed with severe acute respiratory syndrome (SARS). METHODS: Twenty-seven patients who completed both pulmonary function and maximal aerobic capacity tests at 6 and 15 months after the acute illness were invited to return for reassessment. RESULTS: Twenty-one patients (median age 18.2 years, interquartile range (IQR) 16.5-19.7) completed all investigations at 36 months. Pulmonary function was normal in all patients. Maximal aerobic capacity, peak oxygen pulse (peak VO(2) ) and ventilatory anaerobic threshold showed significant improvements compared with values measured at 6 months in both boys and girls. In girls, ventilatory efficiency (ventilatory equivalents for oxygen and carbon dioxide) and perfusion of the lungs (end-tidal partial carbon dioxide pressure) had not increased further compared with the values measured at 15 months. Although peak VO(2) improved further at 36 months in patients with or without persistent radiological abnormalities, the values were 68% (IQR 50-84) and 74% (IQR 60-99), respectively, of those for normal control subjects. CONCLUSIONS: There were improvements in aerobic capacity at 36 months in children affected by SARS; however, the measured values remained suboptimal.

Prevalence of exercise and non-exercise physical activity in Chinese adolescents.

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.

Rehearsal and pedometer reactivity in children.

The main purpose of this study was to investigate whether rehearsal, defined as the tendency to recurrently ruminate over upsetting aversive experiences, had an effect on pedometry reactivity. A total of 156 Hong Kong Chinese children aged 9-12 years were recruited. Participants completed the Rehearsal Scale for Children-Chinese (RSC-C; Ling, Maxwell, Masters, & McManus, 2010) and wore the pedometers for 3 consecutive weeks. The mean number of steps was significantly higher in Week 1 than in Week 3. High rehearsers showed a larger decrease in mean number of steps from Week 1 to Week 3 than low rehearsers. Future physical activity intervention studies should adjust for reactivity in their baseline measurements and should further examine the relationship between habitual PA and individual propensities for rehearsal.

Mobile Health Biometrics to Enhance Exercise and Physical Activity Adherence in Type 2 Diabetes (MOTIVATE-T2D): protocol for a feasibility randomised controlled trial.

INTRODUCTION: Exercise and physical activity (PA) are fundamental to the treatment of type 2 diabetes. Current exercise and PA strategies for newly diagnosed individuals with type 2 diabetes are either clinically effective but unsuitable in routine practice (supervised exercise) or suitable in routine practice but clinically ineffective (PA advice). Mobile health (mHealth) technologies, offering biometric data to patients and healthcare professionals, may bridge the gap between supervised exercise and PA advice, enabling patients to engage in regular long-term physically active lifestyles. This feasibility randomised controlled trial (RCT) will evaluate the use of mHealth technology when incorporated into a structured home-based exercise and PA intervention, in those recently diagnosed with type 2 diabetes. METHODS AND ANALYSIS: This feasibility multicentre, parallel group RCT will recruit 120 individuals with type 2 diabetes (diagnosis within 5-24 months, aged 40-75 years) in the UK (n=60) and Canada (n=60). Participants will undertake a 6-month structured exercise and PA intervention and be supported by an exercise specialist (active control). The intervention group will receive additional support from a smartwatch and phone app, providing real-time feedback and enabling improved communication between the exercise specialist and participant. Primary outcomes are recruitment rate, adherence to exercise and loss to follow-up. Secondary outcomes include a qualitative process evaluation and piloting of potential clinical outcome measures for a future RCT. ETHICS AND DISSEMINATION: The trial was approved in the UK by the South East Scotland Research Ethics Committee 01 (20/SS/0101) and in Canada by the Clinical Research Ethics Board of the University of British Columbia (H20-01936), and is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Results will be published in peer-reviewed journals and presented at national and international scientific meetings. TRIAL REGISTRATION NUMBERS: ISRCTN14335124; ClinicalTrials.gov: NCT04653532.

Health-related physical fitness and weight status in Hong Kong adolescents.

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-and-reach, 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.

Energy intake during activity enhanced video game play.

The purpose of this study was to examine whether the addition of a motor component to video gaming alters energy consumption. To address this problem we used an experimental manipulation design with 9-13 year olds incorporating 'seated video game' and 'activity enhanced video game' conditions, whilst allowing snacks ad libitum. No difference in snacking between the two video gaming conditions was apparent. The children consumed 374 and 383kcalh(-1) during seated and activity enhanced video gaming, respectively. A secondary purpose was to examine consistency of energy intake during free choice video game play. We found no difference in energy intake between four 1h free choice video gaming sessions. Snacking energy intake whilst video gaming was 166% more than the calories required during resting conditions. This study has shown that the addition of a motor component to the video game environment does not alter snack energy intake. However, the high calorific consumption during both seated and activity enhanced video game play highlights the need for an active attempt to restrict snacking whilst playing video games.

Trunk muscle endurance tests: effect of trunk posture on test outcome.

The objective of this study was to investigate the effect of different trunk postures during the abdominal flexor test on isometric endurance holding times and surface electromyographic (EMG) activity of contributing trunk flexor and extensor muscles in 16 healthy college-age male rowers (age, 22.0 ± 1.55 years; height, 179.1 ± 5.47 cm; weight, 68.0 ± 4.18 kg) with a minimum of 12 months rowing experience. Subjects performed 2 maximal effort abdominal flexor tests, 1 held with correct posture and the other with a slightly flexed incorrect trunk posture. Maximum holding time was assessed for each posture while EMG muscle activity was recorded for the external oblique, rectus abdominis, internal oblique, rectus femoris, and lumbar erector spinae muscles. Mean maximal holding time for the incorrectly positioned abdominal flexor test was significantly longer than for the correct position (p < 0.05). EMG activity during the first and last 20% of a time normalized comparison showed significantly lower muscle activity during the incorrect trunk posture in all muscles investigated (p < 0.05). There were no significant differences (p > 0.05) in muscle activity when comparing an equivalent time period at the actual termination of each of the 2 abdominal flexor tests. Although minor variations in trunk posture seem to be acceptable in practice of this isometric abdominal flexor test, the present data indicate that minor lumbar kyphosis deviating away from the correct abdominal flexor test posture can significantly skew test reliability, resulting in longer endurance holding times and relatively lower muscle activity of the trunk muscles.

Development and validation of the Chinese Rehearsal Scale for preadolescent Chinese children.

Roger (1997) defined rehearsal as "the tendency to rehearse or ruminate on emotionally upsetting events" (p. 71). The Rehearsal Scale for Children-Chinese (RSC-C) was developed from the original 14-item Rehearsal Scale of the Emotion Control Questionnaire (Roger & Nesshoever, 1987) after translation and modification for Hong Kong Chinese preadolescents (aged 6-12 years). Confirmatory factor analysis using structural equation modeling revealed that with 1 item deleted from the original scale, the RSC-C possessed good internal validity and satisfactory test-retest reliability within a 1-year period. The new 13-item RSC-C also showed good external validity and internal reliability (alpha=.76). Convergent and discriminant validity was evidenced against the Emotional Problem and the Prosocial Behavior Subscales of the Strengths and Difficulties Questionnaire (Goodman, 1997), respectively. No gender differences in rehearsal scores were found. It was concluded that the 13-item RSC-C could be useful for measuring rehearsal in Chinese preadolescents.

Using heart-rate feedback to increase physical activity in children.

OBJECTIVE: The objective of this study was to test whether heart-rate feedback prompts increased physical activity (PA) in primary school students. METHODS: A controlled trial with 210 9-11 year olds from subsidized Hong Kong Government primary schools was completed in December 2006. Schools were randomly assigned to one of three groups: Control (CG); Educational program (EG); No-educational program (NEG). INTERVENTION: In a short-term school-based intervention, heart-rate feedback was given either in combination with an educational program (EG) or in isolation (NEG). Long-term retention was assessed in comparison to the control group after 6 months follow-up. MAIN OUTCOME MEASURES: Physical activity and changes in attraction to PA. RESULTS: In the short-term, heart-rate monitor feedback increased total daily PA by an average of 24% (p<0.001) and vigorous PA by 0.6% (p<0.05). No change was found for moderate PA. Increases occurred regardless of involvement in the educational program, and in the absence of any change in attitudes towards PA. No long-term retention was apparent. CONCLUSIONS: The findings from the study suggest that feedback from heart-rate monitors encourages low intensity PA, but when removed increases do not persist.

Calibration of the RT3 accelerometer for ambulation and nonambulation in children.

PURPOSE: The purpose of this study was to provide RT3 accelerometer thresholds to distinguish nonambulation from ambulation, as well as distinguish between low, moderate, and vigorous intensity ambulation in Chinese children. METHODS: Thirty-five 8- to 12-yr-olds completed a laboratory-based experiment to calibrate the RT3 device across a range of intensities. Oxygen uptake during sedentary tasks and ambulation was aligned, with corresponding RT3 output, to one of four intensity categories (sedentary, < 2 METs; low, > or = 2 but < 3 METs; moderate, > or = 3 but < 6; and vigorous, > or = 6). Threshold values were derived using receiver operator curves to distinguish the sedentary from low intensity, low from moderate intensity, and moderate from vigorous intensity. These were confirmed in an independent sample of 46 similarly aged children. RESULTS: RT3 movement counts increased in a linear manner with scaled oxygen uptake from stationary to vigorous movement (r(2) = 0.83). The ROC-derived thresholds showed a good ability to discriminate between nonambulatory and ambulatory tasks, as well as distinguish between low, moderate, and vigorous ambulation (sensitivity values of 87-100% and specificity values of 97-100%). ROC analyses in the independent sample showed sensitivity and specificity values ranging from 72 to 98%, indicating that the thresholds provided an accurate distinction between the four intensity categories. A Cohen's kappa of kappa = 0.92 confirmed that the lower threshold had near-perfect agreement with the independent sample, whereas the moderate-intensity and vigorous-intensity thresholds showed good agreement with the independent sample (kappa = 0.63 and 0.65, respectively). CONCLUSION: The RT3 accelerometer provides an acceptable marker of both sedentary and ambulatory behavior in Chinese children.

Physical activity - a neat solution to an impending crisis.

Childhood obesity is arguably the most significant global public health threat, yet effective strategies to contain or prevent the disease are not available. This review examines the physical activity patterns of children and the role physical activity plays in daily energy expenditure. The prevailing focus on moderate to vigorous activity in childhood means there is limited objective information on either sedentary behaviour or non-exercise activity thermogenesis (NEAT), the energy expended during the activities of daily living. Most strategies targeting the prevention of childhood obesity have focused upon adding moderate to vigorous activity and have not been particularly successful. The low efficacy of more purposeful activity is perhaps not surprising because of the small variance in children's physical activity levels explained by moderate to vigorous activity. Subtle changes in NEAT have in contrast been shown to account for differences in fat-mass gain or resistance in adults. Theoretically, manipulating a child's living environment to enhance NEAT would create a positive gain in TDEE, a gain that could lead to the prevention of excess fat-mass. More careful consideration of the specific aspects of physical activity that are most influential in the maintenance of body weight in childhood is a priority. Appreciating the role NEAT may play in the variation of total daily energy expenditure in children is a future challenge for physical activity research. Key pointsExcessive weight gain affects children in both developed and developing countries alike, and results initially from small energy imbalances. Increasing the energy expended in daily living has the potential to re-adjust energy balance and prevent initial excess weight gain.Sedentary behaviour and light intensity movement, as opposed to moderate or vigorous movement, dominate a child's day. We need to understand more about which aspects of activity account for variance in total daily energy expenditure in children.Finding innovative and creative ways to increase the daily energy children expend should be a priority.

Do children emotionally rehearse about their body image?

This study examined the association between propensity for emotional rehearsal, body image self-perception and weight status in Chinese Hong Kong pre-adolescents. Children 8-12 years of age (n = 278) completed measurement of body mass index, body image and emotional rehearsal. Multinomial regression analyses revealed that body mass index was positively associated with body image dissatisfaction and a significant predictor of body size estimation. However, only body size underestimation was associated with lower rehearsal tendencies. The prevalence of body image dissatisfaction and body size estimation was also reported for this population. Future research is suggested for greater understanding of emotional coping in body image dissatisfaction in young children.

Association Between Leisure Time Physical Activity, Cardiopulmonary Fitness, Cardiovascular Risk Factors, and Cardiovascular Workload at Work in Firefighters.

BACKGROUND: Overweight, obesity, and cardiovascular disease risk factors are prevalent among firefighters in some developed countries. It is unclear whether physical activity and cardiopulmonary fitness reduce cardiovascular disease risk and the cardiovascular workload at work in firefighters. The present study investigated the relationship between leisure-time physical activity, cardiopulmonary fitness, cardiovascular disease risk factors, and cardiovascular workload at work in firefighters in Hong Kong. METHODS: Male firefighters (n = 387) were randomly selected from serving firefighters in Hong Kong (n = 5,370) for the assessment of cardiovascular disease risk factors (obesity, hypertension, diabetes mellitus, dyslipidemia, smoking, known cardiovascular diseases). One-third (Target Group) were randomly selected for the assessment of off-duty leisure-time physical activity using the short version of the International Physical Activity Questionnaire. Maximal oxygen uptake was assessed, as well as cardiovascular workload using heart rate monitoring for each firefighter for four "normal" 24-hour working shifts and during real-situation simulated scenarios. RESULTS: Overall, 33.9% of the firefighters had at least two cardiovascular disease risk factors. In the Target Group, firefighters who had higher leisure-time physical activity had a lower resting heart rate and a lower average working heart rate, and spent a smaller proportion of time working at a moderate-intensity cardiovascular workload. Firefighters who had moderate aerobic fitness and high leisure-time physical activity had a lower peak working heart rate during the mountain rescue scenario compared with firefighters who had low leisure-time physical activities. CONCLUSION: Leisure-time physical activity conferred significant benefits during job tasks of moderate cardiovascular workload in firefighters in Hong Kong.