Characterisation of the Mechanical Loads and Metabolic Intensity of the CAPO Kids Exercise Intervention for Healthy Primary School Children

Sedentarism is associated with obesity and other chronic diseases at all ages. Increasing physical activity with in-school interventions, focusing on energy expenditure and bone loading reduces risk of a number of costly chronic diseases. The aim of the current study was to characterise the metabolic and musculoskeletal load intensity of the recent successful CAPO Kids exercise intervention. Pre and early pubertal children (10.4 ± 0.5 years old) from the CAPO Kids trial wore an armband sensor to estimate energy expenditure during a 10-minute CAPO Kids session. Eleven participants performed manoeuvres from the session on a force platform to determine vertical ground reaction forces. In total, 28 boys and 20 girls had armband measures and 11 boys and girls undertook GRF testing. The energy expenditure associated with the 10-minute session was 39.7 ± 9.3 kcal, with an average of 4 kcal·min-1. The intensity of physical activity was ‘vigorous’ to ‘very vigorous’ for 34% of the session. Vertical ground reaction forces of the CAPO Kids manoeuvres ranged from 1.3 ± 0.2 BW (cartwheels) to 5.4 ± 2.3 BW (360° jump). CAPO Kids generates adequate load intensity to stimulate positive health adaptations in both metabolic and musculoskeletal systems of pre and early pubertal children.

Key points

• Energy expenditure of a single bout of CAPO Kids yields 39.7±9.3 kcal and includes activities performed at a vigorous and very vigorous intensity.
• Mechanical loads associated with CAPO Kids surpass five times bodyweight and more than 140 bodyweights per second.
• CAPO Kids intervention represents a viable approach to stimulate musculoskeletal and metabolic adaptation in children.

Key words: Pediatrics, energy expenditure, ground reaction forces, physical activity     

Physical activity patterns and estimated daily energy expenditures in normal and overweight tunisian schoolchildren

Our aim was to test the normality of physical activity patterns and energy expenditures in normal weight and overweight primary school students. Heart rate estimates of total daily energy expenditure (TEE), active energy expenditure (AEE), and activity patterns were made over 3 consecutive school days in healthy middle-class Tunisian children (46 boys, 44 girls, median age (25^th-75^th) percentile, 9.2 (8.8-9.9) years. Our cross-section included 52 students with a normal body mass index (BMI) and 38 who exceeded age-specific BMI limits. TEE, AEE and overall physical activity level (PAL) were not different between overweight children and those with a normal BMI [median values (25^th-75^th) 9.20 (8.20-9.84) vs. 8.88 (7.42-9.76) MJ/d; 3.56 (2.59-4.22) vs. 3.85 (2.77-4.78) MJ/d and 1.74 (1.54-2.04) vs. 1.89 (1.66-2.15) respectively]. Physical activity intensities (PAI) were expressed as percentages of the individual’s heart rate reserve (%HRR). The median PAI for the entire day (PAI₂₄) and for the waking part of day (PAI_w) were lower in overweight than in normal weight individuals [16.3 (14.2-18.9) vs. 20.6 (17.9-22.3) %HRR, p < 0.001) and 24.8 (21.6-28.9) vs.26.2 (24.5-30.8) %HRR, p < 0.01], respectively. Overweight children allocated more of their day to sedentary pursuits [385 (336-468) vs 297 (235-468) min/d, p < 0.001], and less time to moderate physical activity [381(321-457) vs. 460 (380-534) min/d, p < 0.01]. Nevertheless, because of the greater energy cost of a given task, total and active daily energy expenditure did not differ from those with a normal BMI.

Key points

• The physical activity intensity for the entire day (PAI₂₄) and for the waking part of day (PAI_w) were lower in overweight than in normal weight individuals.
• However, because the energy cost of activity is greater in those who are overweight, they do not differ in total energy expenditure or in active energy expenditure.
• Normal children spend more time in moderate activity and less time in sedentary pursuits than overweight children.

Key words: Heart rate monitoring, activity patterns, energy expenditure, excess weight, obesity.     

The Measurement and Interpretation of Children’s Physical Activity

The accurate and reliable assessment of physical activity is necessary for any research study where physical activity is either an outcome measure or an intervention. The aim of this review is to examine the use of objective measurement techniques for the assessment and interpretation of children’s physical activity. Accurate measurement of children’s activity is challenging, as the activity is characteristically sporadic and intermittent, consisting of frequent, short bouts. Objective measures of physical activity include heart rate telemetry, pedometry and accelerometry, and each of these methods has strengths and limitations. Heart rate is suited to the measurement of sustained periods of moderate and vigorous activity, pedometry provides a valid measure of total activity, and accelerometry provides a valid measure of total activity as well as the pattern and intensity of activity. As the weaknesses of heart rate and accelerometry for the assessment of activity are not inter-correlated, a combination of the two methods may be more accurate than either method alone. Recent evidence suggests that the Actiheart, an integrated accelerometer and heart rate unit, provides a more accurate prediction of children’s energy expenditure than either heart rate or accelerometry alone. However, the cost of the Actiheart is prohibitive for large-scale studies. The pedometer is recommended when only the total amount of physical activity is of interest. When the intensity or the pattern of activity is of interest, accelerometry is the recommended measurement tool.

Key points

• The use of objective measures to assess physical activity in children is recommended.
• Pedometers provide an inexpensive objective measure of total activity that is highly correlated with more sophisticated techniques, e.g. accelerometry, and has been used to identify relationships between health and activity in children.
• Accelerometry allows examination of the temporal pattern and intensity of children’s activity, including sporadic physical activity and bouts of physical activity.

Key words: Activity pattern, heart rate, pedometry, accelerometry     

Effects of A School-Based Intervention on BMI and Motor Abilities in Childhood

Obesity in childhood is increasing worldwide. To combat overweight and obesity in childhood, the school-based Children’s Health InterventionaL Trial (CHILT) project combines health education and physical activity. This paper examines the effect of intervention on the body mass index (BMI) and motor abilities after 20.8 ± 1.0 months in 12 randomly selected primary schools compared with 5 randomly selected control schools. The anthropometric data were assessed, BMI was calculated. Coordination was determined by lateral jumping and endurance performance by a 6-minute run. No difference in the prevalence of overweight and obesity was found between the intervention (IS) and control schools (CS) either at baseline or following intervention (each p > 0.05). The increase in the number of lateral jumps was significantly higher in the IS than in the CS (p < 0.001). For the 6-minute run the increase in distance run was significantly improved in IS (p = 0.020). All variables were controlled for gender and age. Overweight and obese children in both IS and CS produced significantly lower scores in coordination and endurance tasks than normal and underweight children during both examinations (each p ≤ 0.001), adjusted for gender and age. Preventive intervention in primary schools offers an effective means to improve motor skills in childhood and to break through the vicious circle of physical inactivity - motor deficits - frustration - increasing inactivity possibly combined with an excess energy intake and weight gain. To prevent overweight and obesity these measures have to be intensified.

Key Points

• School-based prevention improves motor abilities in primary school children.
• The incidence of obesity is not influenced by school-based intervention.
• To prevent obesity in early childhood the measures have to be intensified and parents should be included.

Key Words: Health education, children, obesity, inactivity, physical performance     

Parental Activity as Influence on Childrenˋs BMI Percentiles and Physical Activity

Parents play a crucial role in the development of their children’s lifestyle and health behaviour. This study aims to examine associations between parental physical activity (PA) and children’s BMI percentiles (BMIPCT), moderate to vigorous PA (MVPA) as well as participation in organised sports. Height and body weight was measured in 1615 in German children (7.1 ± 0.6 years, 50.3% male) and converted to BMIPCT. Parental BMI was calculated based on self-reported height and body weight. Children’s MVPA and sports participation as well as parental PA were assessed via parental questionnaire. Analysis of covariance (ANCOVA), controlling for age and family income was used to examine the association between parental and children’s PA levels as well as BMIPCT. 39.7% of the parents classified themselves as physically active and 8.3% of children were classified as overweight or obese. Lower BMIPCT were observed with both parents being physically active (44.5 ± 26.3 vs. 50.2 ± 26.9 and 52.0 ± 28.4, respectively). There was no association between parental and children’s PA levels but children with at least one active parent displayed a higher participation in organised sports (102.0 ± 96.6 and 117.7 ± 123.6 vs. 73.7 ± 100.0, respectively). Children of active parents were less likely to be overweight and obese. The lack of association between subjectively assessed parental PA and child MVPA suggests that parental support for PA in children is more important than parents being a role model. More active parents, however, may be more likely to facilitate participation in organised sports. These results underline the importance of the inclusion of parents in health promotion and obesity prevention programmes in children.

Key points

• A higher prevalence of overweight or obese children was found with inactive parents.
• Children’s BMI percentiles were lower if both parents were physically active compared to children whose parents were both inactive or only had one physically active parent.
• Parental activity had no influence on daily time spent at MVPA and time spent in non-organised sports.
• There was a significant association between parental physical activity and the number of minutes per week boys and girls participated in organised sports.
• On average, children who had at least one physically active parent spent significantly more time participating in organised sports than children with inactive parents.

Key words: Health and exercise, effects on body weight, health promotion     

Energy Expenditure and Intensity of Physical Activity in Soccer Referees During Match-Play

The aim of this study was to determine the caloric expenditure and the intensity of physical activities performed by official soccer referees during a match expressed in Metabolic Equivalent (METs). The physical activity of referees accredited by CBF (Brazilian Confederation of Soccer) was video-recorded during twenty-nine official games of Paraná Championship (Brasil), Series A and B of the 2005/2006. Computerized video analysis was used to determine the time spent in 6 locomotor activities (standing still, walking, jogging, backwards running, running and sprint). The frequency and duration of each activity were recorded and these data were utilized to calculate the distance covered by the referee. Energy expenditure values were estimated, utilizing specific equations, from the time players spent in each motor activity. The referees observed in this study had a mean age of 38.9 ± 3.8 years, body mass of 86.1 ± 7.1 kg, stature of 1.80 ± 0.07 m and a body mass index of 26.5 ± 0.6 kg·m^-2. During match-play, referees covered an average distance of 9155.4 ± 70.3 meters (8411 - 9765), with a mean energy expenditure of 734.7 ± 65 kcal. This energy expenditure was significantly reduced in the second half: 359.9 ± 6.3 vs 374.7 ± 6.6 kcal (p = 0.006), and averaged to be moderate energy intensity (5 METs) with predominant utilization of the aerobic energy system. In total, during 67% of match-play the intensity was equal or lower than 3.8 METs and in 33% it was higher than 9.8 METs. The pattern of movement observed in the present study confirms that soccer refereeing may be considered as a highly intermittent exercise mode. The high to low-intensity activity ratio may be defined as 1:7.1. In conclusion, referees officiating in professional soccer matches in Brazil should perform a physical conditioning regime that provides the stamina required at this level and consume appropriate and adequate nutrition to meet the energetic demands for match-play.

Key points

• In order to elaborate a diet that sufficiently restores the athlete’s energy expenditure during training and/or competition, the first step would be to measure energy expenditure during activity.
• We observed that during officials matches soccer referees perform physical aerobic activities of low and moderate intensity, and present a significant decline in energy expenditure between the first and second half.
• The pattern of movement observed in the present report confirms that soccer referees, like players undertake intermittent type exercise.
• Nutritional habits of soccer referees must be adapted to their daily physical activities, short training periods and moderate energy intensity physical activity, on average, during match refereeing.

Key words: Motion-analysis, referee, football, METs, oxygen consumption     

Energy Regulation in Young People

Obesity in young people is now realised as a worldwide crisis of epidemic proportion. The aetiology of this disease suggests a disruption in regulation of energy at the population level, leading to a positive energy balance and excess adiposity. The relative contribution of food intake and physical inactivity remains to be elucidated. Treatment interventions have aimed to create a deficit in energy balance through manipulation of physical activity, behavioural components or, to a lesser extent, dietary modification. Whether such intervention is maintained in the long-term is as yet unclear, however it seems a combination of therapies is optimal. Mindful of a mismatch between energy intake and expenditure, recent work has begun to examine the acute relationship between physical activity and food intake in children. Initial findings suggest a short-term delay in compensation through energy intake for exercise- induced energy expenditure. The overarching study of energy regulation in children and adolescents is clearly multifaceted in nature and variables to be assessed or manipulated require careful consideration. The collection of paediatric physical activity, energy expenditure and food intake data is a time-consuming process, fraught with potential sources of error. Investigators should consider the validity and reliability of these and other issues, alongside the logistics of any proposed study. Despite these areas of concern, recent advances in the field should provide exciting opportunities for future research in paediatric energy regulation on a variety of levels.

Key points

• Physical activity appears to be an effective intervention in paediatric weight-management, however future studies need to be extended over the longer-term employing consistent protocols to aid comparison.
• In the short-term, exercise-induced energy expenditure and subsequent energy intake do not appear to be tightly regulated in young people; this acute imbalance is similar to the ‘loose coupling’ of energy described for adults.
• The relationship between energy expenditure and food intake in young people requires further examination in longer-term interventions. A rigorous protocol is necessary to study parameters under free-living conditions.

Key words: Obesity, children, diet, energy expenditure     

Validity and Reliability of Physical Activity Measures in Greek High School Age Children

The aim of this study was to determine the validity and reliability of 3 physical activity questionnaires in Greek high school children. Forty children participated in the study aged M = 13.73 (SD 0.8 years). The validation study was conducted by comparing an accelerometer (MTI/CSA Model 7164) to 3 questionnaires: a) Three-day Physical Activity Record (3DPAR), b) Four by One-Day Recall Physical Activity Questionnaire (4BY1RPAQ) and c) Physical Activity and Life Style Questionnaire (PALQ). Validity of the 3 self-report questionnaires was assessed against the MTI/CSA accelerometer by comparing the scores obtained by each instrument on the first week of measurement. Reliability was assessed with two consecutive measurements performed two weeks apart. The measures of reliability were assessed by Intra Class Correlation, Typical Error and Limits of Agreement. A two-way ANOVA for repeated measures was performed. Repeated measures were week and day; in order to determine differences between the two scores obtained with the two measurements for MTI/CSA, 3DPAR and 4BY1RPAQ. A paired Student’s t-test was performed for the two scores obtained with the PALQ. Post-hoc multiple comparisons were performed using the Bonferroni test. Significance for all parts of the analysis was determined at an alpha level of p < 0.05. A paired Student’s t-test was performed for the two scores obtained with the PALQ. Results of this study indicated that reliability measured by intra class correlations (ICC) were for MTI/CSA (ICC = 0.52, p < 0.05), 3DPAR (ICC = 0.97, p < 0.01), 4BY1RPAQ (ICC = 0.70, p < 0.01), and PALQ (ICC = 0.52, p < 0.01). Significant Pearson product moment correlation coefficients (r) were observed between MTI/CSA and the other instruments, as a measure of validity: 3DPAR (r = 0.63, p < 0.01), 4BY1RPAQ (r = 0.62, p < 0.01), and PALQ (r = 0.53, p < 0.01). The reliability of the four instruments used in this study was acceptable. Validity correlations were also significant for the three self-report instruments used in this study.

Key Points

• The PALQ demonstrated a moderate reliability (0.52) and validity (0.53) in recording physical activity.
• A relatively high correlation was observed between the MTI/CSA and 3DPAR and a moderate correlation was observed between MTI/CSA and the 4BY1RPAQ tested in this study.
• Only a combination of the available instruments would be able to respond to the interpersonal and intrapersonal variability when assessing physical activity in children and adolescents. Self-report instruments and accelerometers are probably able to quantify only gross fluctuations in physical activity.
• All 4 instruments used in this study were valid and reliable in recording physical activity when used with children, since the instruments were able to detect changes in physical activity and the respective energy cost.

Key Words: Physical activity, activity monitors, energy expenditure, children, validity, reliability     

Seasonal Differences in Physical Activity and Sedentary Patterns: The Relevance of the PA Context

The aim of this pilot study was to characterize seasonal variation in the moderate to vigorous physical activity (MVPA) and sedentary behavior of Portuguese school youth, and understand the influence of activity choices and settings. The participants in this study were 24 students, aged 10-13 years. Accelerometers measured daily PA over 7 consecutive days, in different seasons May - June and January - February. In summer, boys accumulated more minutes in MVPA (928 minutes/week) than girls (793 minutes/week). In winter the pattern was reversed with girls accumulating more activity than boys (736 minutes/week vs. 598 minutes/week). The repeated measures ANOVA revealed significant effects for season (F = 5.98, p = 0.023) and in- school vs. out-of-school (F = 6.53, p = 0.018). Youth were more active in the summer and activity levels were higher after school than in school. Summer season provided relevant contexts for youth physical activity accumulation. Winter season may have been a significant barrier to boy’s preferred PA context. Differences in choices of outdoor or indoor PA, after school, explained the gender differences in seasonal activity patterns.

Key points

• Detailed temporal profiling of the accelerometer data.
• Information provided about the context of PA.
• Boys had different activity patterns with considerably less MVPA and more sedentary behavior during the winter time.
• Girls had more consistent PA patterns across seasons.

Key words: Season, accelerometer, physical activity context     

Analysis of the physical activity patterns of a rural Afrikaner population in the south-western Cape

To determine whether low levels of energy expenditure at work or in leisure-time might contribute to the high prevalence of coronary heart disease among white rural Afrikaners, 7188 whites of both sexes in three rural communities were questioned about their physical activities. From these data, the percentage of the population at different ages participating in sedentary, moderate or vigorous activity at work or light, moderate or vigorous leisure-time activity was calculated. Total energy expenditure at work or in leisure-time was also calculated. At all ages, less than 1% of both men and women performed workday activities requiring high energy output. Beginning after the age of 24 years, there was a dramatic fall in the percentage of both men and women participating in either moderate or vigorous leisure-time physical activity. After the age of 44 years, less than 26% of men and 16% of women exceeded the coronary 'protective threshold' of 8400 kJ leisure-time energy expenditure per week. Thus the population studied is characterized by very low levels of energy expenditure particularly at work, but also during leisure-time.     

Changes in daily physical activity before and after total hip arthroplasty. A pilot study using accelerometry

The present single-centre prospective follow-up study assessed the objective changes in physical activity undertaken before and after total hip arthroplasty (THA) using accelerometry. We enrolled 12 female patients who underwent home-based accelerometry assessment one month before and six months after the THA procedure. We assessed the daily amount of physical activity and energy expenditure related to physical activities. We also recorded the intensity of the physical activity, and pre- and post-operative clinical evaluation with the Harris Hip Score (HHS). At 6 months after surgery, we found a statistically significant increase of the total energy cost of physical activity (DA) (P = 0.02), without significant increase of activity time (P > 0.05). The energy cost of moderate/vigorous activity was statistically significant increased after surgery (P = 0.008). Finally, HHS improved form 53.9 ± 15.3 pre-operatively to 78.1 ± 12.2 post-operatively (P = 0.03). In our patients, the improvement was significant only for the total energy cost of daily activity. Thus, although patients did not exhibit a more active lifestyle, as shown by the slight increase of the activity time, they significantly increased the amount of moderate or vigorous activities performed after surgery.     

The Effects of Exercise on Food Intake and Hunger: Relationship with Acylated Ghrelin and Leptin

This study investigated the effects of a long bout of aerobic exercise on hunger and energy intake and circulating levels of leptin and acylated ghrelin. Ten healthy male subjects undertook two, 4 h trials in a randomized crossover design. In the exercise trial subjects ran for 105 min at 50% of maximal oxygen uptake and the last 15 min at 70% of maximal oxygen uptake followed by a 120 min rest period. In the control trial, subjects rested for 4 h. Subjects consumed a buffet test meal at 180 min during each trial. Hunger ratings, acylated ghrelin, leptin, glucose and insulin concentrations were measured at 0, 1, 2, 3 and 4 h. No differences were found at baseline values for hunger, acylated ghrelin, leptin, insulin and glucose for both trials (p > 0.05). The estimated energy expenditure of the exercise trial was 1550 ± 136 kcal. Exercise did not change subsequent absolute energy intake, but produced a significant decrease (p < 0.05) in relative energy intake. A two-way ANOVA revealed a significant (p < 0. 05) interaction effect for hunger and acylated ghrelin. In conclusion, this exercise regimen had a positive effect on reducing appetite which is related to reduced acylated ghrelin responses over time. This finding lends support for a role of exercise in weight management.

Key points

• Physical exercise is a strategy used to counteract obesity, since it lowers the energetic balance by increasing energy expenditure. However, because any energy expended in exercise elevates the intensity of hunger and drives food consumption, it is pertinent to ask how effective exercise could be in helping people to lose weight or to prevent weight gain.
• The effects of exercise on hunger sensations and food intake are fairly controversial and depend on the intensity and duration of exercise.
• 120 min prolonged treadmill exercise with mix intensity, temporarily decreased hunger sensations, acylated ghrelin and relative energy intake.
• Variations in exercise intensity should theoretically be a useful means of weight loss.

Key words: Energy intake, energy expenditure, exercise, hunger, acylated ghrelin, weight loss, appetite     

Intensity and Timing in Life of Recreational Physical Activity in Relation to Breast Cancer Risk Among Pre- and Postmenopausal Women

Regular recreational physical activity has been found to be associated with a decrease in breast cancer risk in women in the majority of epidemiologic studies, but research findings are inconsistent regarding the intensity of activity and timing in life. To address these issues the relations of moderate and vigorous intensity recreational physical activity during ages 14-20, 21-34, 35-50, and over age 50 years to pre- and postmenopausal breast cancer risk were examined. A case-control study of 858 women, with histological confirmation of invasive breast cancer, and 1085 controls, free of any cancer diagnosis, all subjects aged 28-79 years was conducted in the Region of Western Pomerania (Poland). Physical activity was assessed using a self-administered questionnaire with questions on type of activity, duration, frequency, and intensity for each type of activity. Odds ratios (OR) and 95% confidence intervals (CI) of breast cancer associated with physical activity were calculated using unconditional logistic regression. Vigorous physical activity at ages 14-20 and 21-34 years lowered breast cancer risk by at least 35% in premenopausal women and by at least 51% in postmenopausal women for the highest versus lowest quartiles of the activity. The risk was also reduced in postmenopausal women who reported on average more than 1.74 hours per week of vigorous intensity recreational activity in ages >50 years (OR = 0.58; 95%CI = 0.27-0.97; P for trend = 0.013). For moderate activity the relationships remained statistically significant only in postmenopausal women active during ages 14- 20 years. The results indicate also a plausible risk reduction among premeno-pausal women. These results support the hypothesis that recrea-tional activity, particularly done early in life, is associated with a decrease in the invasive breast cancer risk in postmenopausal women. Among premenopausal women, only vigorous forms of activity may significantly decrease the risk.

Key points

• Recreational physical activity of vigorous intensity during ages 14-20 and 21-34 years protect against breast cancer regardless of menopausal status.
• Vigorous recreational physical activity at ages >50 years was also associated with reduced postmeno-pausal breast cancer risk.
• The risk reduction was also observed among post-menopausal women engaged in recreational physical activity of moderate intensity at ages 14-20 years.

Key words: Exercise, breast cancer, case-control study, prevention     

PRIDE for PLAY: Personal Responsibility in Daily Effort for Participation in Lifelong Activity for Youths. A Singaporean Context

Singapore, a developed city state of four million people is experiencing the pitfalls that come with rapid modernisation and economic progress- elevated disease risk factors among adults and young people. Weekly compulsory physical education classes of 70 minutes in schools and the associated sports activities after classes are inadequate to meet emergent physical activity guidelines of a daily accumulation of at least 90 minutes of physical activity of at least moderate intensity. Daily play sessions that are exclusive of an active daily recess, physical education classes taught by trained specialists and after-school sport sessions, can provide many developmental and holistic health benefits that may carry over into adulthood. A school environment that is play-encouraging, play-enabling and play-inviting can be a useful, innovative and natural way of inculcating a love for movement and help redress a serious trend of physical activity insufficiency while youngsters engage electronic gaming activities. Pilot initiatives for the PRIDE (personal responsibility in daily effort) for PLAY (participation in lifelong activity for youths) programme is a radicalised approach in a number of primary schools in Singapore to infuse daily physical play of between 20 to 45 minutes during curriculum hours. The hope is that PRIDE for PLAY will reap benefits of improved holistic health of youngsters- better physical, social, emotional and mental attributes. While PRIDE for PLAY is no panacea to all of the ills of modernisation, it will go some way in helping the students of tomorrow to be physically healthy, socially more engaged and tolerant of others, mentally more apt to problem-solve and emotionally more proficient to embrace working life in adulthood.

Key points

• Physical play is natural among young people and a daily dose of play can help young people meet daily requirements for accumulated physical activity of at least 90 minutes and at least of a moderate intensity.
• Play is critical for child development and provides a healthy balance for many sedentary lifestyle activities.
• Parents, care-givers and teachers should emphasise and partake in daily play with young people.

Key words: Daily play, physical activity, children, Singapore     

Energy Expenditure and Habitual Physical Activities in Adolescent Sprint Athletes

This study aimed to assess total energy expenditure (TEE) and specific habitual physical activities in adolescent sprint athletes. Two methods used to estimate TEE, an activity diary (AD) and SenseWear armband (SWA), were compared. Sixteen athletes (6 girls, 10 boys, mean age 16.5 ± 1.6 yr) simultaneously wore a SWA and completed an AD and food diary during one week. Basal energy expenditure as given by the SWA when taken off was corrected for the appropriate MET value using the AD. TEE as estimated by the AD and SWA was comparable (3196 ± 590 kcal and 3012 ± 518 kcal, p = 0.113) without day-to-day variations in TEE and energy expended in activities of high intensity. Daily energy intake (2569 ± 508 kcal) did not match TEE according to both the AD and SWA (respectively p < 0.001 and p = 0.007). Athletes were in a supine position for a longer time on weekend days than on week days and slept longer on Sundays. Athletes reported a longer time of high-intensive physical activities in the AD than registered by the SWA on 4 out of 7 days. In addition to specific sprint activities on 3 to 7 days per week, 11 out of 16 athletes actively commuted to school where they participated in sports once or twice per week. The AD and the SWA are comparable in the estimation of TEE, which appears realistic and sustainable. The SWA offers an appropriate and objective method in the assessment of TEE, sleeping and resting in adolescent athletes on the condition that detailed information is given for the times the armband is not worn. The AD offers activity specific information but relies on the motivation, compliance and subjectivity of the individual, especially considering high-intensive intermittent training.

Key points

• The activity diary and Sensewear armband provide comparable estimates of TEE in adolescent sprint athletes.
• A high inter-individual variation was observed in time spent in high-intensity physical activities, advocating an individual based assessment when coaching athletes.
• The activity diary is useful when detailed information on specific physical activities is desired. The Sensewear armband offers objective information on sleeping, resting, and physical activity duration.
• Wearing the Sensewear combined with reporting on activities when the Sensewear is not worn and when doing specific activities of interest results in more complete information.

Key words: Indirect calorimetry, armband, exercise, sleep     

Daily Physical Activity and Physical Fitness in 11-to 15-year-old Trained and Untrained Turkish Boys

The aims of this study were to assess levels and patterns of physical activity (PA) in relation to age and regular sport activity, and to examine its relationship to physical fitness in trained and untrained boys. One hundred forty-seven 11-to 15- year-old boys (73 trained and 74 untrained) participated in this study. Trained boys, comprised of 26 soccer, 25 handball and 22 volleyball players, had been training regularly for at least one year. The intensity, duration and frequency of PA were assessed from four complete days of heart rate monitoring with 15-seconds sampling intervals. Aerobic fitness was assessed by determining peakVO₂ with a portable breath-by-breath gas analyzer (Cosmed K4b²) and the running speeds at fixed lactate concentrations during an incremental running test. Anaerobic fitness was evalu-ated with the Wingate Anaerobic Test. Skinfold thicknesses from eight sites and Tanner stages of pubic hair were also obtained. Based on 15-s heart rate data, instead of continuous activity, multiple short bouts of moderate and vigorous PA, lasting up to one minute, were characteristic of daily PA patterns of both trained and untrained boys. PA levels of trained boys were higher than untrained boys (p < 0.01) and the levels of PA decreased with age and maturation in both groups (p < 0.05). Daily PA variables were related to body fatness in both groups (p < 0.05), but the relationships were not consistent in the trained group. Daily PA variables were also related to aerobic fitness in the untrained group (p < 0.05) and these relationships were somewhat better with vigorous PA, whereas in the trained group, none of the PA variables were related to any of the aerobic fitness indices (p > 0.05). No relationship was observed between PA variables and anaerobic fitness in either group (p> 0.05). It seems that such relationships may somewhat depend on the fitness level of the subjects.

Key points

• PA levels of trained boys were higher than untrained boys and the levels of PA decreased with age and maturation in both groups.
• Based on the 15-s HR data, instead of continuous activity, multiple short bouts of moderate and vigorous PA, lasting up to one minute, were characteristic of daily PA patterns of both trained and untrained boys.
• Daily PA variables were related to aerobic fitness in the untrained group and these relationships were somewhat better with vigorous PA (>70% HRR), whereas in the trained group, none of the PA variables were related to any of the aerobic fitness indices.
• Neither peak nor mean power values were related to any of the daily PA variables in both trained and untrained groups.

Key words: Physical activity, training, aerobic and anaerobic fitness, body fatness, children     

Physical activity, calcium intake and childhood bone mineral: a population-based cross-sectional study

Summary

In a free-living cohort of 4-year old children, mean daily time in moderate?Cvigorous physical activity and daily calcium intake at 3?years, were positively related to hip bone size and density. Relationships between physical activity and bone indices were stronger when calcium intake was above compared with below median (966?mg/day).

Introduction

We examined the cross-sectional relationships between childhood physical activity, dietary calcium intake and bone size and density.

Methods

Children aged 4?years were recruited from the Southampton Women's Survey. They underwent measurement of bone mass by DXA (Hologic Discovery). Physical activity was assessed by accelerometry (Actiheart, Cambridge Neurotechnology Ltd, Cambridge, UK) for seven continuous days.

Results

Four hundred twenty-two children (212 boys) participated. In a cross-sectional analysis, after adjusting for gender, daily mean time(minutes per day) spent in moderate to very vigorous activity (MVPA) was positively related to hip BA (R ²?=?3%, p?<?0.001), BMC (R ²?=?4%, p?<?0.001), aBMD (R ²?=?3%, p?=?0.001) and estimated vBMD (R ²?=?2%, p?=?0.01), but not height (r _s?=?0.04, p?=?0.42) or weight (r _s?=?0.01, p?=?0.76). Mean daily calcium intake (assessed at 3?years old) positively predicted bone indices in those with a calcium intake below the median (966?mg/day), but there was a much attenuated relationship in those above this. These associations persisted after inclusion of total energy, protein and phosphorus in multivariate models. The relationships between MVPA and bone indices were stronger in children with calcium intakes above the median. Thus, for aBMD, the variance explained by MVPA when daily calcium intake was below the median was 2% (p?=?0.1) and above median was 6% (p?=?0.001).

Conclusions

These results support the notion that adequate calcium intake may be required for optimal action of physical activity on bone development and that improving levels of physical activity and calcium intake in childhood may help to optimise accrual of bone mass.     

Physical Activity and Suicide Attempt of South Korean Adolescents - Evidence from the Eight Korea Youth Risk Behaviors Web-based Survey

Suicide is the leading cause of death among South Korean adolescents. The purpose of this study was to examine the relationship between suicidal thoughts (ST) and suicidal attempts (SA) with the level of physical activity (PA) among South Korean adolescents. Based on data from the eighth Korea Youth Risk Behaviors Web-Based Survey, 74,186 South Korean adolescents were evaluated in terms of their relationship between meeting guidelines for vigorous PA (VPA), moderate PA (MPA), and low PA (LPA) and in respect of ST and SA status. The adjusted odds ratio in adolescents who thought about suicide increased significantly with PA levels (1.02 in males, 1.21 in females with VPA, 1.10 in males, 1.18 in females with MPA, and 1.16 in males, 1.20 in females with LPA) compared to participants who did not think about suicide. In addition, the AOR in adolescents who attempted suicide increased significantly with PA levels (1.16 in males, 1.36 in females with VPA, 1.13 in males, 1.15 in females with MPA, and 1.26 in males, 1.15 in females with LPA) compared to participants who did not attempt suicide. These results show that VPA, MPA, and LPA are positively associated with ST and SA prevention in South Korean adolescents. Therefore, to prevent suicide of South Korean adolescents, we support public health program including PA participation.

Key Points

• South Korean male adolescents, compared to female adolescents, showed relatively high values for physical activity-related variables such as vigorous, moderate, and low PA.
• Regardless of gender, more physical activity participation is positively associated with prevention of suicidal thought and attempts of South Korean adolescents.
• To prevent suicide of South Korean adolescents, we support public health program including meeting guidelines for vigorous, moderate, and low physical activity.

Key words: Suicide, physical activity, odds ratio, KYRBWS