A 7-day activity diary for assessment of daily energy expenditure validated by the doubly labelled water method in adolescents

Physical activity, cardiorespiratory fitness, and metabolic syndrome in adolescents: a cross-sectional study

Background

In adults, there is a substantial body of evidence that physical inactivity or low cardiorespiratory fitness levels are strongly associated with the development of metabolic syndrome. Although this association has been studied extensively in adults, little is known regarding this association in adolescents. The aim of this study was to analyze the association between physical activity and cardiorespiratory fitness levels with metabolic syndrome in Brazilian adolescents.

Methods

A random sample of 223 girls (mean age, 14.4 ± 1.6 years) and 233 boys (mean age, 14.6 ± 1.6 years) was selected for the study. The level of physical activity was determined by the Bouchard three-day physical activity record. Cardiorespiratory fitness was estimated by the Leger 20-meter shuttle run test. The metabolic syndrome components assessed included waist circumference, blood pressure, HDL-cholesterol, triglycerides, and fasting plasma glucose levels. Independent Student t-tests were used to assess gender differences. The associations between physical activity and cardiorespiratory fitness with the presence of metabolic syndrome were calculated using logistic regression models adjusted for age and gender.

Results

A high prevalence of metabolic syndrome was observed in inactive adolescents (males, 11.4%; females, 7.2%) and adolescents with low cardiorespiratory fitness levels (males, 13.9%; females, 8.6%). A significant relationship existed between metabolic syndrome and low cardiorespiratory fitness (OR, 3.0 [1.13-7.94]).

Conclusion

The prevalence of metabolic syndrome is high among adolescents who are inactive and those with low cardiorespiratory fitness. Prevention strategies for metabolic syndrome should concentrate on enhancing fitness levels early in life.

[Validity and reliability of self-report instruments for measuring physical activity in adolescents: a systematic review]

This was a systematic review of studies on the reliability and validity of self-report instruments for measuring physical activity, or subjective measurements, in adolescents (10-18 years). Searches were conducted in databases (MEDLINE, PsycInfo, SportsDiscus, Scopus, Web of Science, SciELO, Lilacs) and in the references of the retrieved articles. Sixty-six studies met the inclusion criteria. The majority were from North America, with only 5 from Brazil. Fifty-two different instruments were identified: 42 questionnaires, 6 diaries or logs, and 4 interviews. "Test-retest" reliability varied from 0.20 to 0.98; the majority (28/50) of the coefficients showed values < 0.70. Validity coefficients showed wide variation (-0.13 to 0.88), with the majority (64/84) < or = 0.50. Only 3 instruments displayed correlations > or = 0.70. Various instruments were tested in adolescents, especially questionnaires. These instruments generally showed better "test-retest" reliability than validity.

Physical activity energy expenditure of adolescents in India

Physical activity (PA) has rarely been quantified in adolescent populations undergoing economic transition; therefore relationships with disease still remain uncertain. This study assessed whether absolute PA energy expenditure (PAEE), PAEE/kg, and PAEE/kg(FFM) could be accurately estimated using accelerometry and a questionnaire in Indian adolescents and how these values compared to those of other populations. PAEE was assessed using doubly labeled water (DLW) in 30 adolescents from Chennai, India, over seven consecutive days, simultaneous with the measurement of PA using accelerometry and a previous-week recall questionnaire. Accelerometry counts (regression analysis) and questionnaire data were used to estimate PAEE; estimates were cross-validated using the Bland-Altman method. Accelerometry data and DLW-derived PAEE were visually compared to values from four North American and European populations. For boys, 49% of the variance in DLW-derived PAEE was explained with an equation including accelerometry counts and fat-free mass (FFM). Questionnaire-derived estimates did not contribute to the explained variance in DLW derived PAEE. The group-level PA of these Indian adolescents was successfully assessed using accelerometry, but not questionnaire. DLW-derived PAEE/kg(FFM) (mean (s.d.): 53.0 (27.5) kJ/kg(FFM)/day) was lower in this group than other adolescent populations in Europe and similar to those in North America. Additionally, four boys and none of the girls accumulated ≥60 min/day of accelerometry-derived moderate intensity activity, indicating low levels of PAEE and PA in these adolescents. Further research is necessary to investigate the association between PA and health outcomes in Indian adolescents.

Adiposity and age explain most of the association between physical activity and fitness in physically active men

BACKGROUND

To determine if there is an association between physical activity assessed by the short version of the International Physical Activity Questionnaire (IPAQ) and cardiorespiratory and muscular fitness.

METHODOLOGY/PRINCIPAL FINDINGS

One hundred and eighty-two young males (age range: 20-55 years) completed the short form of the IPAQ to assess physical activity. Body composition (dual-energy X-Ray absorptiometry), muscular fitness (static and dynamic muscle force and power, vertical jump height, running speed [30 m sprint], anaerobic capacity [300 m running test]) and cardiorespiratory fitness (estimated VO(2)max: 20 m shuttle run test) were also determined in all subjects. Activity-related energy expenditure of moderate and vigorous intensity (EEPA(moderate) and EEPA(vigorous), respectively) was inversely associated with indices of adiposity (r = -0.21 to -0.37, P<0.05). Cardiorespiratory fitness (VO(2)max) was positively associated with LogEEPA(moderate) (r = 0.26, P<0.05) and LogEEPA(vigorous) (r = 0.27). However, no association between VO(2)max with LogEEPA(moderate), LogEPPA(vigorous) and LogEEPA(total) was observed after adjusting for the percentage of body fat. Multiple stepwise regression analysis to predict VO(2)max from LogEEPA(walking), LogEEPA(moderate), LogEEPA(vigorous), LogEEPA(total), age and percentage of body fat (%fat) showed that the %fat alone explained 62% of the variance in VO(2)max and that the age added another 10%, while the other variables did not add predictive value to the model [VO(2)max  = 129.6-(25.1× Log %fat) - (34.0× Log age); SEE: 4.3 ml.kg(-1). min(-1); R(2) = 0.72 (P<0.05)]. No positive association between muscular fitness-related variables and physical activity was observed, even after adjusting for body fat or body fat and age.

CONCLUSIONS/SIGNIFICANCE

Adiposity and age are the strongest predictors of VO(2)max in healthy men. The energy expended in moderate and vigorous physical activities is inversely associated with adiposity. Muscular fitness does not appear to be associated with physical activity as assessed by the IPAQ.

[Determining factors of physical activity level in school children and adolescents: the OPACA study]

INTRODUCTION

Physical activity is a key factor for human health. This study attempts to measure the level of physical activity in children and to find out what are the factors that determine it.

METHOD

In a sample of the 11 and 14 year-old population of the centre-south area of Palencia, physical activity was measured using a three day diary, and anthropometric and socioeconomic variables were collected. Three variables were analysed: fat-free mass adjusted activity energy expenditure (AEE/FFM), physical activity level (PAL), and categorical physical activity (active/inactive).

RESULTS

A total of 179 children were included, of whom 71.5% were active or very active. Males were more active than females, and activity was also higher in summer. Physical activity declined between 11 and 14 years, and was lower during the weekends than in working days. There were no differences related to obesity, overweight or percent body fat. More active children had lower blood pressure. Physical activity was directly related to weekly hours spent in sport activities, and inversely related to time spent on sedentary activities. Multivariate analysis showed that children from families with low educational levels had a higher activity level not related to sport activities.

CONCLUSIONS

The level of physical activity in this population is acceptable, although there are sex differences and there is a declining trend through the adolescence.

Promoting physical activity in children with juvenile idiopathic arthritis through an internet-based program: results of a pilot randomized controlled trial

OBJECTIVE

Patients with juvenile idiopathic arthritis (JIA) are less physically active than healthy peers. Therefore, we developed an Internet-based intervention to improve physical activity (PA). The aim of this study was to examine the effectiveness of the program in improving PA.

METHODS

PA was determined by activity-related energy expenditure, PA level, time spent on moderate to vigorous PA, and the number of days with > or =1 hour of moderate to vigorous activity, and was assessed with a 7-day activity diary. Aerobic exercise capacity was assessed by means of a Bruce treadmill test and was recorded as maximum endurance time. Disease activity was assessed by using the JIA core set. Adherence was electronically monitored.

RESULTS

Of 59 patients, 33 eligible patients were included and randomized in an intervention (n = 17, mean +/- SD age 10.6 +/- 1.5 years) or control waiting-list group (n = 16, mean +/- SD age 10.8 +/- 1.4 years). All patients completed baseline and T1 testing. PA significantly improved in both groups. Maximum endurance time significantly improved in the intervention group but not in the control group. In a subgroup analysis for patients with low PA (intervention: n = 7, control: n = 5), PA improved in the intervention group but not in the control group. The intervention was safe, feasible, and showed a good adherence.

CONCLUSION

An Internet-based program for children with JIA ages 8-12 years directed at promoting PA in daily life effectively improves PA in those patients with low PA levels. It is also able to improve endurance and it is safe, feasible, and has good adherence.

Is the International Physical Activity Questionnaire-short form (IPAQ-SF) valid for assessing physical activity in Chronic Fatigue Syndrome?

PURPOSE

To evaluate the criterion validity and internal consistency of the International Physical Activity Questionnaire-short form (IPAQ-sf) in Chronic Fatigue Syndrome (CFS) patients.

METHOD

Fifty-six CFS patients completed the IPAQ-sf after they wore a tri-axial accelerometer and filled out activity diaries during 1 week. Spearman rank correlation coefficients and Cronbach's Alpha were calculated.

RESULTS

The IPAQ-sf correlated significantly with the energy expenditure and Metabolic Equivalents (METs) minutes spent moderately to vigorously active following the activity diary and accelerometer. These correlation coefficients were however low (r varying between 0.282 and 0.426) and rather irrelevant, since CFS patients hardly reach moderate or vigorous activity levels. Internal consistency between the three subitems used for the total score of the IPAQ-sf was 0.337.

CONCLUSION

The observed associations between the IPAQ-sf data and the data obtained from the accelerometer (gold standard) and the diaries were too low to be in support of the use of the IPAQ-sf in patients with CFS. The IPAQ-sf does not seem an appropriate tool to assess physical activity in CFS patients. Further study is required to seek for a valid, practical and affordable tool.

Using activity diaries to measure children's and adolescents' compliance with activity restrictions after mild traumatic brain injury

PURPOSE

To examine the extent to which children and adolescents with a mild traumatic brain injury (MTBI) comply with the activity restrictions received upon discharge from a pediatric trauma center.

PARTICIPANTS

Thirty-four children with MTBI (aged 8-16 years) and 34 control children matched for age, sex, and premorbid level of physical activity.

MAIN MEASURE

Activity diary documenting the exact level of activity during 3 consecutive days during the 1st, 4th, and 12th week post-MTBI (corresponding time intervals for controls) and the Physical Activity Questionnaire.

RESULTS

Fifteen pairs of children (MTBI + control) completed the diaries for all 3 assessment times (77% participation rate among consecutive admissions and 44% compliance rate with diary completion). Although some children engaged in activities before the end of the 4-week restriction period, the majority of the children followed the recommendations they received. Children with MTBI maintained a lower level of energy expenditure at the 1- and 4-week evaluations than did the noninjured children, but not at the 12-week evaluation.

CONCLUSION

Children with MTBI usually comply with the activity restrictions they receive upon discharge from the hospital.

Year-round high physical activity levels in agropastoralists of Bolivian Andes: results from repeated measurements of DLW method in peak and slack seasons of agricultural activities

By the repeated use of the doubly labeled water method (DLW), this study aimed to investigate (1) the extent of changes in energy expenditure and physical activity level (PAL) in response to increased agricultural work demands, and (2) whether the seasonal work demands induce the changes in the fairly equitable division of work and similarity of energy needs between men and women observed in our previous study (Phase 1 study; Kashiwazaki et al., 1995: Am J Clin Nutr 62: 901-910). In a rural small agropastoral community of the Bolivian Andes, we made the follow-up study (Phase 2, 14 adults; a time of high agricultural activity) of the Phase 1 study (12 adults; a time of low agricultural activity). In the Phase 2 study, both men and women showed very high PAL (mean+/-SD), but there was no significant difference by sex (men; 2.18 +/- 0.23 (age; 64 +/- 11 years, n = 7), women; 2.26 +/- 0.25 (63 +/- 10 years, n = 7)). The increase of PAL by 11% (P = 0.023) in the Phase 2 was equally occurred in both men and women. The factorial approach underestimated PAL significantly by approximately 15% (P < 0.05). High PAL throughout the year ranging on average 2.0 and 2.2 was attributable to everyday tasks for subsistence and domestic works undertaking over 9-11 h (men spent 2.7 h on agricultural work and 4.7 h on animal herding, whereas women spent 7.3 h almost exclusively on animal herding). The seasonal increase in PAL was statistically significant, but it was smaller than those anticipated from published reports. A flexible division of labor played an important role in the equitable energetic increase in both men and women.

Physical activity in women: effects of a self-regulation intervention

BACKGROUND

A physically active lifestyle during midlife is critical to the maintenance of high physical functioning. This study tested whether an intervention that combined information with cognitive-behavioral strategies had a better effect on women's physical activity than an information-only intervention.

DESIGN

A 4-month longitudinal RCT comparing two brief interventions was conducted between July 2003 and September 2004. Analyses were completed in June 2008.

SETTING AND PARTICIPANTS

256 women aged 30-50 years in a large metropolitan area in Germany.

INTERVENTION

The study compared a health information intervention with an information + self-regulation intervention. All participants received the same information intervention; participants in the information + self-regulation group additionally learned a technique that integrates mental contrasting with implementation intentions.

MAIN OUTCOME MEASURES

Self-reported minutes of moderate-to-vigorous physical activity per week.

RESULTS

Participants in the information + self-regulation group were twice as physically active (i.e., nearly 1 hour more per week) as participants in the information group. This difference appeared as early as the first week after intervention and was maintained over the course of the 4 months. Participants in the information group slightly increased their baseline physical activity after intervention.

CONCLUSIONS

Women who learned a self-regulation technique during an information session were substantially more active than women who participated in only the information session. The self-regulation technique should be tested further as a tool for increasing the impact of interventions on behavioral change.

Validation of a 7-day physical activity diary against doubly-labelled water

BACKGROUND

The assessment of physical activity intensity and duration is essential for understanding group activity patterns.

METHODS

The present study evaluated the validity of measurement of total energy expenditure (TEE) and physical activity level (PAL) using a categorized physical activity diary. In 29 young healthy men, aged 18-27 years, with body mass index range 21-43 kg m(-2), TEE using doubly-labelled water (DLW), resting metabolic rate (RMR) by indirect calorimetry, physical activity level (PAL defined as TEE/RMR) and activity pattern, timing and level from 7-day physical activity diaries were determined.

RESULTS

TEE by DLW and estimated by activity diary were correlated (r = 0.61, p = 0.005). The mean underestimation of TEE by the activity diary compared with the DLW method was 2.50 +/- 0.72 MJ day(-1). Sedentary (lying, sitting and standing) time averaged 18 h day(-1) and was negatively correlated with PAL (r = -0.44, p = 0.018) whilst time spent in light intensity activity (5 h day(-1)) was positively correlated (r = 0.51, p = 0.005).

CONCLUSIONS

It is concluded that the categorized physical activity diary measured TEE with limited accuracy but presents an inexpensive, convenient method of discriminating individual and group physical activity patterns.

Assessment of physical activity in youth

Despite much progress with physical activity assessment, the limitations concerning the accurate measurement of physical activity are often amplified in young people due to the cognitive, physiological, and biomechanical changes that occur during natural growth as well as a more intermittent pattern of habitual physical activity in youth compared with adults. This mini-review describes and compares methods to assess habitual physical activity in youth and discusses main issues regarding the use and interpretation of data collected with these techniques. Self-report instruments and movement sensing are currently the most frequently used methods for the assessment of physical activity in epidemiological research; others include heart rate monitoring and multisensor systems. Habitual energy expenditure can be estimated from these input measures with varying degree of uncertainty. Nonlinear modeling techniques, using accelerometry perhaps in combination with physiological parameters like heart rate or temperature, have the greatest potential for increasing the prediction accuracy of habitual physical activity energy expenditure. Although multisensor systems may be more accurate, this must be balanced against feasibility, a balance that shifts with technological and scientific advances and should be considered at the beginning of every new study.

Reliability and validity of the habitual activity estimation scale (HAES) in patients with cystic fibrosis

PURPOSE

To understand potential benefits of exercise in the cystic fibrosis (CF) population, there needs to be accurate methods to quantify it. The Habitual Activity Estimation Scale (HAES) questionnaire has been shown to be a feasible tool to measure physical activity however the reliability and validity have yet to be determined in the CF population.

METHODS

Fourteen (seven male, seven female) patients aged 16.2 +/- 4.2 years with CF participated in this study. Participants were clinically stable at the time of the study and participating in their habitual physical activity. To assess reliability, patients completed the HAES and a validated 3-day activity diary, and wore an ActiGraph Accelerometer for two consecutive weeks. Validity was assessed by comparing the activity results of each of the three instruments over a single week time period.

RESULTS

ICC estimates of reliability for the HAES, diary, and accelerometer were 0.72 (P < 0.0001), 0.76 (P < 0.0001), 0.63 (P < 0.0001), respectively. Validity analysis indicated that there were significant relationships between the participants' activity results as estimated by the HAES, diary and accelerometer. Further, significant relationships were detected between activity measures when broken into morning, afternoon, or evening periods, and between measures from weekday or weekend days. There were also significant relationships among the three instruments when recording different activity levels (somewhat inactive, somewhat active, and very active).

CONCLUSION

The findings of this study suggest that the HAES questionnaire is a reliable and valid instrument that can be used to assess activities of varying intensity in patients with CF.

Defining the Volume and Intensity of Sport Participation in Adolescent Rugby Union Players

Purpose:

Investigating adolescent training loads might help us understand optimal training adaptations. GPS tracking devices and training diaries were used to quantify weekly sport and other physical activity demands placed on adolescent rugby union players and profile typical rugby training sessions.

Methods:

Participants were 75 males age 14 to 18 y who were recruited from rugby teams representing 3 levels of participation: schoolboy, national representative, and a selective sports school talent squad.

Results:

Schoolboy players covered a distance of (mean ± SD) 3511 ± 836 m, representative-squad players 3576 ± 956 m, and talent-squad players 2208 ± 637 m per rugby training session. The representative squad recorded the highest weekly duration of sport and physical activity (515 ± 222 min/wk), followed by the talent squad (421 ± 211 min/week) and schoolboy group (370 ± 135 min/wk). Profiles of individual players identified as group outliers showed participation in up to 3 games and up to 11 training sessions per week, with twice the weekly load of the team averages.

Conclusion:

Optimal participation and performance of adolescent rugby union players might be compromised by many high-load, high-impact training sessions and games and commitments to other sports and physical activities. An improved understanding of monitoring and quantifying load in adolescent athletes is needed to facilitate best-practice advice for player management and training prescription.

Injury risk from popular childhood physical activities: results from an Australian primary school cohort

BACKGROUND

Children engage in various physical activities that pose different injury risks. However, the lack of adequate data on exposure has meant that these risks have not been quantified or compared in young children aged 5-12 years.

OBJECTIVES

To measure exposure to popular activities among Australian primary school children and to quantify the associated injury risks.

METHOD

The Childhood Injury Prevention Study prospectively followed up a cohort of randomly selected Australian primary and preschool children aged 5-12 years. Time (min) engaged in various physical activities was measured using a parent-completed 7-day diary. All injuries over 12 months were reported to the study. All data on exposure and injuries were coded using the International classification of external causes of injury. Injury rates per 1000 h of exposure were calculated for the most popular activities.

RESULTS

Complete diaries and data on injuries were available for 744 children. Over 12 months, 314 injuries relating to physical activity outside of school were reported. The highest injury risks per exposure time occurred for tackle-style football (2.18/1000 h), wheeled activities (1.72/1000 h) and tennis (1.19/1000 h). Overall, boys were injured more often than girls; however, the differences were non-significant or reversed for some activities including soccer, trampolining and team ball sports.

CONCLUSION

Although the overall injury rate was low in this prospective cohort, the safety of some popular childhood activities can be improved so that the benefits may be enjoyed with fewer negative consequences.

No differences in physical activity in (un)diagnosed asthma and healthy controls

To establish whether asthma affects physical activity levels in children (aged 7-10 years) we evaluated physical activity levels in children with undiagnosed asthma (UDA), diagnosed asthma (DA), and healthy controls (HCs). A cross-sectional community-based study was performed which included a parental questionnaire on their child's respiratory health, and testing of airway reversibility and bronchial hyperresponsiveness (BHR). DA was defined as the parents' confirmation of a physician's diagnosis of asthma in the past 12 months. UDA was defined by asthma symptoms combined with airway reversibility or BHR in children without a physician's diagnosis of asthma. Physical activity was measured during 5 days with an accelerometer and a diary, and with the habitual activity estimation scale which reviews the physical activity during the past 2 weeks. The final study population comprised 1,614 children of whom 81 (5%) had DA, 130 (8%) UDA, and 202 HCs. Baseline FEV(1) % was lowest in children with UDA (UDA FEV(1) 94% predicted, DA FEV(1) 98% predicted, HCs FEV(1) 100% predicted). Using the three methods, no differences were found in the physical activity between children with UDA, DA, and HCs. Childhood asthma does not appear to be associated with a decreased level of daily physical activity in our study population.

Estimating under-reporting of energy intake in dietary surveys using an individualised method

Under-reporting (UR) of energy intake (EI) by self-reported dietary methods is well-documented but the methods used to estimate UR in population-based studies commonly assume a sedentary lifestyle. We compared estimated UR using individualised estimates of energy requirements with a population cut-off based on minimum energy needs. UR was estimated for 1551 adults aged 19-64 years enrolled in the National Diet and Nutrition Survey. Physical activity diaries and 7 d weighed dietary records were completed concurrently. Mean daily EI (kJ/d) was calculated from the dietary records. Reported physical activity was used to assign each subject's activity level, and then to calculate estimated energy requirements (EER) from published equations. UR was calculated both as EER - EI with an adjustment for daily EER and EI variation, and also by a population method. By the individual method UR was approximately 27 % of energy needs in men and 29 % in women, with 75 % of men and 77 % of women classified as under-reporters; by the population method 80 and 88 % were classified as under-reporters respectively. When subjects who reported their eating being affected by dieting or illness during dietary recording were excluded, UR was 25 % of energy needs in both sexes. UR was higher in overweight and obese men and women compared with their lean counterparts (P < 0.001). UR of EI must be considered in dietary surveys. The EER method allows UR to be quantified and takes into account an individual's activity level. Measures of physical activity and questions to identify under-eating during dietary recording may help to evaluate secular trends in UR.

Dispêndio energético diário e níveis de lipídeos-lipoproteínas plasmáticos em adolescentes

O objetivo do estudo foi analisar o impacto da prática habitual de atividade física, mediante estimativas do dispêndio energético diário (DEdiário), no perfil lipídico-lipoprotéico plasmático em amostra representativa de adolescentes. A amostra foi constituída por 452 sujeitos (246 moças e 206 rapazes) com idade entre 15 e 18 anos. As concentrações de lipídeos-lipoproteínas plasmáticas foram estabelecidas por procedimentos laboratoriais. As informações acerca da prática habitual de atividade física foram obtidas por intermédio de instrumento retrospectivo de auto-recordação. Estabeleceram-se estimativas quanto ao DE Diário com base no custo calórico associado ao tipo e à duração das atividades registradas pelos adolescentes. A amostra foi estratificada em três grupos de prática habitual de atividade física: os menos ativos, < 25º percentil do DE Diário; os moderadamente ativos, 25-75º percentil do DEdiário; e os mais ativos, > 75º percentil do DEdiário, e também pontos de corte para um perfil lipídico-lipoprotéico de risco aterogênico. Os resultados da análise de co-variância, controlando a participação do índice de massa corporal, mostraram que as concentrações de HDL-C foram significativamente diferentes de acordo com os grupos crescentes de DEdiário em moças (p = 0,009) e em rapazes (p = 0,010), porém, o comportamento de variação dos valores observados foi diferente nos dois sexos. A análise de regressão logística indicou que o risco relativo para menores valores de HDL-C foi duas vezes maior entre os adolescentes menos ativos em comparação com os mais ativos. Em ambos os sexos, as concentrações de colesterol total, LDL-C e triglicerídeos não apresentaram diferenças significativas entre os grupos de DEdiário. Em conclusão, a prática habitual de atividade física mais intensa e o maior DEdiário estão associados com mais elevadas concentrações de HDL-C em adolescentes de ambos os sexos, independentemente das variações do peso corporal. As associações entre DEdiário e os outros componentes plasmáticos de lipídeos-lipoproteínas tratados no presente estudo foram fracas e inconsistentes.

Comparing different measures of energy expenditure in human subjects resident in a metabolic facility

OBJECTIVE

To compare energy expenditure (EE) measured by doubly labeled water (DLW) with other measures, both physical and based on subjective questionnaires.

DESIGN

A comparison of methods in a stratified sample of adult volunteers.

SETTING

The feeding behaviour suite (FBS) at the Rowett Research Institute, Aberdeen.

SUBJECTS

A total of 59 subjects, stratified for age, sex and body mass index (BMI).

INTERVENTIONS

EE was assessed by DLW (validated using measurements of energy balance), heart rate monitor (HRM), activity monitor (Caltrac), 24-h physical activity diary (PAD) and 7-day physical activity recall. Energy intake was assessed using covert (investigator-weighed) food intake (EI). Data were collected over a 12-day period of residence in the Rowett's FBS.

RESULTS

No methods correlated highly with physical activity assessed by DLW. Physical methods correlated more closely than did subjective recording. All methods (except EI) significantly underestimated EE, estimated by DLW. There were no significant differences in association between methods and sex, age, BMI or fat-free mass.

CONCLUSION

EE is difficult to measure precisely or accurately with current approaches but physical methods are slightly better than subjective accounts.

Comparison of the TriTrac-R3D accelerometer and a self-report activity diary with heart-rate monitoring for the assessment of energy expenditure in children

Determining total energy expenditure (EE) in children under free-living conditions has become of increasingly clinical interest. The aim of this study was to compare three different methods to assess EE triaxial accelerometry (TriTrac-R3D; Professional Products, Division of Reining International, Madison, WI, USA), activity diary and heart-rate (HR) monitoring combined with indirect calorimetry (IC). Twenty non-obese children and adolescents, aged 5.5 to 16.0 years, participated in this study. Results from the three methods were collected simultaneously under free-living conditions during the same 24 h schoolday period. Neither activity diary (5904 (SD 1756) KJ) NOR THE TRITRAC-R3D (6389 (sd 979) kJ) showed statistical differences in 24 h total EE compared with HR monitoring (5965 (sd 1911) kJ). When considering different physical activity (PA) periods, compared with HR monitoring, activity diary underestimates total EE during sedentary periods (P<0·001) and overestimates total EE and PA-EE during PA periods (P<0·001) because of the high energy cost equivalence of activity levels. The TriTrac-R3D, compared with HR monitoring, shows good agreement for assessing PA-EE during PA periods (mean difference +0·25 (sd 1·9) kJ/min; 95 % CI for the bias -0·08, 0·58), but underestimates PA-EE and it does not show good precision during sedentary periods (-0·87 (sd 1·4) kJ/min, P<0·001). Correlation between the vector magnitude generated by the TriTrac-R3D accelerometer and EE of activities derived from HR monitoring is high. When compared with the HR method, the TriTrac-R3D and activity diary are not systematically accurate and must be carefully used for the assessment of children's EE depending on the purpose of each study.

Protein requirements in male adolescent soccer players

Few investigations have studied protein metabolism in children and adolescent athletes which makes difficult the assessment of daily recommended dietary protein allowances in this population. The problematic in paediatric competitors is the determination of additional protein needs resulting from intensive physical training. The aim of this investigation was to determine protein requirement in 14-year-old male adolescent soccer players. Healthy male adolescent soccer players (N = 11, 13.8 +/- 0.1 year) participated in a short term repeated nitrogen balance study. Diets were designed to provide proteins at three levels: 1.4, 1.2 and 1.0 g protein per kg body weight (BW). Nutrient and energy intakes were assessed from 4 day food records corresponding to 4 day training periods during 3 weeks. Urine was collected during four consecutive days and analysed for nitrogen. The nitrogen balances were calculated from mean daily protein intake, mean urinary nitrogen excretion and estimated faecal and integumental nitrogen losses. Nitrogen balance increased with both protein intake and energy balance. At energy equilibrium, the daily protein intake needed to balance nitrogen losses was 1.04 g kg(-1) day(-1). This corresponds to an estimated average requirement (EAR) for protein of 1.20 g kg(-1) day(-1) and a recommended daily allowance (RDA) of 1.40 g kg(-1) day(-1) assuming a daily nitrogen deposition of 11 mg kg(-1). The results of the present study suggest that the protein requirements of 14-year-old male athletes are above the RDA for non-active male adolescents.

Energy requirements of children and adolescents

Total energy expenditure (TEE) was calculated at 1–18 years of age from measurements with doubly labelled water (DLW) in 483 boys and 646 girls, and heart rate monitoring (HRM) in 318 boys and 162 girls. Studies on obese, underweight and stunted groups were not included. TEE of populations with different lifestyles was estimated by factorial calculations in 42 studies on time allocation involving 1982 boys and 1969 girls in developed industrialised countries, and 1236 boys and 1116 girls in developing countries. Quadratic polynomial models were best to predict TEE in boys (TEE(MJ day−1) = 1.298 + 0.265 kg − 0.0011 kg2, r = 0.982, SEE = 0.518) and girls (TEE(MJ day−1) = 1.102 + 0.273 kg − 0.0019 kg2, r = 0.955, SEE = 0.650). TEE at 1–2 years was reduced by 7% based on DLW measurements and TEE estimates of infants. Energy requirements (ER) were calculated adding 8.6 kJ (2 kcal) for each gram of weight gained during growth. Compared with the 1985 FAO/WHO/UNU values1, ER were 18–20% lower from 1 to 7 years of age, 12% lower for boys and 5% lower for girls at 7–10 years, and 12% higher for either gender from 12 years onwards. Differences between industrialised and developing countries, the variance in DLW and HRM studies, and the standard error of the estimate (SEE) of the quadratic predictive equations, suggested that ER should be adjusted after 5 years of age by ±15% in populations with more or less physical activity than an average lifestyle. Physical activity recommendations must accompany dietary recommendations in order to maintain optimal health and reduce the risk of diseases associated with sedentary lifestyles.

Determinants of sufficient daily activity in Australian primary school children

AIMS

Australian guidelines recommend that children participate in at least one hour of physical activity every day. We aimed to measure physical activity participation in a random sample of Australian primary school children and to determine the biological, behavioural, environmental and social influences associated with insufficient daily activity.

METHOD

We analysed the following cross-section data from a randomly selected sample of children (N=518) aged 5 to 12 years: age, gender, socioeconmic status (SES) indicators, family size, home play equipment availability, transport method to school, and estimated time per week in physical and sedentary activity. Logistic regression analysis was performed to determine variables that were associated with insufficient (<60 minutes) daily activity.

RESULTS

Seventy-six children (15% of the cohort) failed to meet the minimum activity recommendations of 60 minutes of daily activity. These children were significantly less likely to walk or cycle to school (adjusted odds ratio (OR) 0.43; 95% CI=0.24-0.77) or participate in organised sports or activity (OR 0.42; 95% CI=0.28-0.64) and were more likely to spend in excess of 2 hours a day watching television of using a computer for entertainment (OR 2.10 (1.16-3.78). Age, gender, SES and family size were not significantly associated with insufficient activity.

CONCLUSION

There exists a significant proportion of the paediatric population who are insufficiently active. Interventions to encourage increased activity in this sub-group may be successful if they seek to alter sedentary behaviour (namely television use) and method of transportation to and from school.

Concurrent validation of the Bouchard Diary with an accelerometry-based monitor

PURPOSE

This study was conducted to examine the relationships between the Bouchard activity diary and a temporally matched objective measure: the Tritrac-R3D (Professional Products, Reining International, Madison, WI) accelerometer. A secondary purpose was to examine the intraindividual variability in correlation coefficients between the two temporally matched measures.

METHODS

A total of 70 participants (ages 18-23 yr) wore a Tritrac monitor and completed the Bouchard activity diary during a 24-h period. Estimates of activity energy expenditure (AEE) and total energy expenditure (TEE) were compared using correlations, t-tests, and Bland-Altman graphical procedures.

RESULTS

A strong linear relationship was found between the Tritrac and the Bouchard measure for both AEE (r = 0.72) and TEE (r = 0.86). Large and significant differences were seen in the estimates of AEE (576 +/- 381 kcal) and TEE (645 +/- 494) from the two instruments. The Bouchard diary yielded higher estimates of TEE than the Tritrac for nearly all participants (97%) and the Bland-Altman plots revealed a systematic bias in the relationships (smaller bias for lower energy expenditure levels and higher bias for higher energy expenditure estimates). Intraindividual correlations between estimated TEE from the Tritrac and Bouchard diary ranged from 0.34 to 0.93 (mean r = 0.74).

CONCLUSION

The overall response indicates that individuals are able to provide reasonable self-reported estimates of their activity levels across a day.

Factorial estimation of daily energy expenditure using a simplified method was improved by adjustment for excess post-exercise oxygen consumption and thermic effect of food

This study validated a simplified factorial method for measuring energy expenditure (EE) against EE measured by doubly labelled water (DEE), and investigated whether adjustment for excess post-exercise oxygen consumption (EPOC) and thermic effect of food (TEF) as described by Institute of Medicine (2002) improved the factorial measure. Seventeen normal weight subjects (10 females, seven males) were recruited from among university staff and students. Factorial EE was measured using a 16-activity-category method, published energy costs of activities and measured basal metabolic rate, before (FEE) and after (FEE(adj)) adjustment for EPOC and TEF, and by DEE. FEE underestimated daily EE by 14.6% relative to DEE (P = 0.000), but this underestimate was improved to 5.1% (P = 0.071) when FEE was adjusted for EPOC and TEF. Individual differences between DEE and FEE(adj) ranged from -20.2 to 17.6%, with 88% of subjects showing differences of less than +/-12%.

Within- and between-individual variability in estimated energy expenditure and habitual physical activity among young adults

OBJECTIVE

To examine the within- and between-individual variability in the estimated total energy expenditure (TEE) and habitual physical activity (PA) in free-living young adults. We were specifically interested in the day-to-day variation.

DESIGN

Cross-sectional.

SETTING

University.

SUBJECTS

A total of 277 (125 males, 152 females) participants aged 18-24 years.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Subjects recorded their daily PA with the Bouchard 3-day diary. Descriptive statistics for TEE, moderate-to-vigorous physical activity (MVPA), inactivity (IA), and activity energy expenditure (AEE) were calculated and presented as a frequency distribution. Within- and between-individual variability were tested by RMANOVA and also presented as the coefficient of variation (CV).

RESULTS

Mean values for TEE, MVPA, AEE, and IA were comparable between males and females; however, considerable between-individual variability existed. Only MVPA showed a significant difference between sexes (P<0.05), due to slightly greater vigorous PA in males compared to females (8.0 and 6.8 kcal/kg/day, respectively; P=0.12). Results from the RMANOVA revealed no significant day-to-day variability in any TEE or PA variable and the CVs were not significantly different between males and females. TEE and IA displayed mean CVs of approximately 12% while mean CVs for AEE and MVPA approximated 32 and 84%, respectively.

CONCLUSIONS

Results from this study suggest (1) a limited day-to-day variability in TEE and (2) a large degree of between-individual variation for TEE and PA exist. This study highlights the importance of understanding the variability associated with TEE, which is important for PA measurement and proper PA and nutritional recommendations.

SPONSORSHIP

None.

Physical activity, energy expenditure and their correlates in two cohorts of Swedish subjects between adolescence and early adulthood

OBJECTIVE

To assess physical activity and energy expenditure and to identify their correlates during adolescence and early adulthood.

DESIGN

In a cohort study, total energy expenditure (TEE) and physical activity level (PAL) were assessed at 15 and 21 y from a 7-day activity diary and predicted BMR. The influences on TEE and PAL of body size, gender, sexual maturity, physical activity habits, sitting time, region, social conditions, employment, food habits, smoking and alcohol intake were examined in multivariate analyses.

SUBJECTS

71 male and 89 female subjects, living in two socioeconomically different regions of Sweden, a university region and an industrial region.

SETTING

The university city of Uppsala and the industrial town of Trollhättan.

RESULTS

At both 15 and 21 y, PAL and TEE were high, with gender, sitting time and physical activity habits as main correlates. At age 21 y, employment and the mother's educational level also appeared as significant correlates. The relations between the main variables and their correlates were more complex than at age 15 y, and the sitting time was reduced and the activity habits were changed.

CONCLUSIONS

A reduction of daily sitting appears to be a major reason why high levels of physical activity and energy expenditure were maintained from 15 to 21 y of age in spite of changed and less frequent activity habits during this interval.

Sex differences in habitual physical activity and lung function decline in children with cystic fibrosis

OBJECTIVES

To evaluate the feasibility of measuring habitual physical activity (HPA) in children with cystic fibrosis (CF) and to assess the relation between HPA and the rate of decline in FEV1 over a period of 2 years.

STUDY DESIGN

At regular clinic visits, 109 patients (7 to 17 years; 56 girls) performed pulmonary function testing and completed the Habitual Activity Estimation Scale (HAES). Patients were divided into quartiles, based on activity levels derived from the HAES.

RESULTS

Girls in the two lowest activity quartiles had a more rapid rate of decline FEV1 (-3.40% and -3.05% predicted, respectively) than girls in the two highest activity quartiles (-0.93% and +1.17% predicted, respectively) (P = .02). In boys, the rate of decline of FEV1 was similar in all activity quartiles (-1.95% predicted). Patients reported significantly more activity in summer compared with spring, winter, and fall (P < .0001), and boys reported greater activity than girls (6.5 +/- 2.9 vs 5.4 +/- 2.5 h/d, P < .05).

CONCLUSIONS

The annual rate of change of FEV1 was related to activity quartile in girls but not in boys. This research suggests that an inactive lifestyle may partially explain the poorer survival of female patients with CF. The HAES is a feasible tool for routine follow-up of HPA in our CF clinic.

Relação entre diferentes índices de atividade física e preditores de adiposidade em adolescentes de ambos os sexos

OBJETIVO: Determinar a relação entre diferentes índices de atividade física e preditores de adiposidade em adolescentes de ambos os sexos. MÉTODOS: Foram avaliadas 111 crianças (57 meninos e 54 meninas), com idade média de 11,62 ± 0,72. Como preditores de adiposidade foram determinados o IMC, percentagem de gordura corporal e a relação cintura/quadril (RCQ). Quanto aos indicadores de atividade física, calcularam-se o gasto energético total (GET), nível de atividade física habitual (NAFH), nível de atividade física (NAF) e gasto energético com atividade física (GEat) através do questionário de Bouchard e, para a taxa metabólica basal (TMB), a equação de Schofield-HW. RESULTADOS: A amostra apresentou diferenças significativas entre os sexos para idade, % de gordura corporal, RCQ, NAFH, NAF, TMB com p < 0,05. Para os meninos o GET, NAF, TMB e GEat apresentaram correlação significativa com o IMC (r = 0,86; r = 0,70; r = 0,91; r = 0,78) e % de gordura (r = 0,78; r = 0,61; r = 0,90; r = 0,70) com p < 0,01, respectivamente, e o GET, TMB, GEat apresentaram correlação significativa com o RCQ (r = 0,28; r = 0,45 e r = 0,28) com p < 0,05. Para as meninas o GET, NAF, TMB, GEat apresentaram valores significativos com o IMC (r = 0,86; r = 0,82; r = 0,78; r = 0,85); em % de gordura todos os indicadores GET, NAFH, NAF, TMB e GEat foram significativos (r = 0,73; r = -0,29; r = 0,66; r = 0,74; r = 0,70) com p < 0,05. CONCLUSÃO: Os diferentes indicadores de nível de atividade física apresentaram significativa correlação com os preditores de adiposidade com exceção do RCQ para as meninas. O aumento da massa corporal demonstrou relação significância com o aumento do dispêndio energético em função da maior necessidade de energia para movimentar o corpo.

Gender differences in habitual activity in children with cystic fibrosis

AIMS

(1) To compare habitual activity levels in prepubescent and pubescent boys and girls with different degrees of CF lung disease severity and healthy controls. (2) To assess the relation between habitual activity levels and measures of fitness, lung function, nutrition, pancreatic status, and quality of life.

METHODS AND RESULTS

A total of 148 children (75 girls and 73 boys) with CF and matched controls were studied. Regardless of disease severity, there were no differences in habitual activity between prepubescent boys and girls with CF. Pubescent boys with CF were significantly more active than girls with the same degree of disease severity. There were no significant differences in habitual activity between prepubescent children with CF and controls. Pubescent children with mild CF were significantly more active than controls, but those with moderate to severe disease were less active than controls. The best correlates with habitual activity levels were anaerobic power, aerobic capacity, and quality of life. In children with moderate to severe disease, nutrition status correlated significantly with activity levels. The impact of pancreatic status on activity levels and other measures of fitness was most apparent in pubescent girls.

CONCLUSION

Gender differences in habitual activity were evident only after the onset of puberty. The impact of pancreatic insufficiency on measures of fitness and habitual activity was greatest in pubescent females. The reason for this gender difference may be an interplay of genetic, hormonal, and societal factors and is the focus of a longitudinal study.

Physical activity and levels of inactivity in adolescent females ages 11-16 years in the United Arab Emirates

The purpose of this study was to investigate patterns of physical activity and levels of inactivity in adolescent females in the United Arab Emirates (UAE). A total of 58 adolescent females, age 11-16 years, were recruited from two female-only governmental schools in Abu-Dhabi. Subjects were divided into two groups: 11-13 years (n = 22) and 14-16 years (n = 36). Physical activity patterns were determined from a 3-day activity diary. Total energy expenditure (TEE) was estimated using a factorial approach. The amount of physical activity was expressed as the physical activity level (PAL) and the activity-related energy expenditure (AEE). The number of hours spent watching television was estimated from the activity diaries. There were no significant differences in the energy expenditure parameters between age groups or between schooldays and weekends. PAL was low in both age groups. Television was the predominant leisure time pursuit. The number of hours per day spent watching television (median and interquartile range) was 2.5 (2.3-3.1) in 11-13 years and 2.5 (2.3-2.8) in 14-16 years. Television-watching was significantly higher during the weekend than schooldays: 11-13 years (P = 0.006) and 14-16 years (P < 0.001). In conclusion, the amount of physical activity undertaken by adolescent females in the UAE was very low. Cultural and weather restrictions and social change of the community in the UAE are not conducive to physical activity and play a major role in levels of physical inactivity. This may explain, in part, the rise in the incidence of obesity in this population.

Minnesota leisure time activity questionnaire and doubly labeled water in adolescents

PURPOSES

To validate the energy expenditure estimated from The Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ) with total energy expenditure (TEE) measured by doubly labeled water (DLW), and to present and examine the validity of an extended version of the MLTPAQ with additional questions about inactivity during leisure time (eMLTPAQ), in a sample of Swedish 15-yr-old adolescents.

METHODS

Thirty-five 15-yr-old adolescents were interviewed using the eMLTPAQ. In addition to anthropometry, indirect calorimetry was measured to assess basal metabolic rate, and TEE was assessed by the DLW method over a 14-d period.

RESULTS

Energy expenditure calculated from MLTPAQ correlated well with TEEDLW (r=0.49, P<0.01), and the correlation increased when including questions about inactivity (r=0.73, P<0.01). However, eMLTPAQ underestimated TEE in 34 of the 35 students, with a mean difference between the methods of 2.8 MJ.d(-1) (95% limits of agreement: -0.1 to 5.6 MJ.d(-1)), which mainly was explained by a relative high intensity in the time which remained unreported.

CONCLUSION

eMLTPAQ is valid in ranking adolescents energy expenditure and in describing patterns of leisure time physical activities.

Muscle Function and Resting Energy Expenditure in Female Athletes with Cystic Fibrosis

The pathophysiology of impaired exercise tolerance in patients with cystic fibrosis (CF) is not completely understood. The objective of this study was to compare exercise ability (at clinical and cellular levels) and resting energy expenditure in female athletes with CF compared with matched control subjects. Sixteen subjects and matched control subjects participated in the study. The girls with CF not only had a significantly greater resting energy expenditure (7.6% higher; p<0.05), their habitual daily activity was also significantly greater than that of control subjects (15% greater; p<0.01). Peak aerobic capacity was similar in both groups. However, peak anaerobic power was 20% less (p<0.05) in girls with CF. The 31P magnetic resonance spectroscopy studies demonstrated that there were no differences between the groups at rest, but at 25% total work output the girls with CF were less acidotic (CF, pH 6.99 [0.06]; control subjects, 6.90 [0.05]) and had a significantly lower inorganic phosphorus-to-phosphocreatine ratio (CF, 0.34 [0.07]; control subjects, 0.41 [0.08]). These differences continued to increase to maximal exercise. This study demonstrates that in spite of normal lung function and good nutritional status, females athletes with CF still had significant deficiencies in some measures of fitness and muscle metabolism compared with healthy athletes.

Estimating human energy expenditure: a review of techniques with particular reference to doubly labelled water

This review includes an historical overview of the techniques for measuring energy expenditure (EE). Following this overview, the "gold standard" method of measuring EE, the doubly labelled water (DLW) method, is emphasised. Other methods, such as direct calorimetry, indirect calorimetry systems, heart rate and EE relationships, questionnaires and activity recall, motion sensors, combined heart rate and motion sensors for the estimation of EE are then highlighted in relation to their validation against the DLW method. The major advantages and disadvantages for each method are then considered. The preferred method to determine EE is likely to depend principally on factors such as the number of study participants to be monitored, the time period of measurements and the finances available. Small study participant numbers over a short period may be measured accurately by means of indirect calorimetric methods (stationary and portable systems). For periods over 3-4 days, EE should ideally be measured using the DLW method. However, the use of motion sensors is very promising in the measurement of EE, and has a number of advantages over the DLW method. Furthermore, if used correctly, both heart rate and questionnaire methods may provide valuable estimates of EE. Additional studies are needed to examine the possibility of improving the accuracy of measurement by combining two or more techniques. Such information, if confirmed by scientific rigour, may lead to an improvement in the estimation of EE and population-based physical activity levels. The accurate measurement of physical activity and EE is critical from both a research and health prospective. A consideration of the relevant techniques used for the estimation of EE may also help improve the quality of these frequently reported measurements.

Influence of body composition on physical activity validation studies using doubly labeled water

This study investigated the influence of two approaches (mathematical transformation and statistical procedures), used to account for body composition [body mass or fat-free mass (FFM)], on associations between two measures of physical activity and energy expenditure determined by doubly labeled water (DLW). Complete data for these analyses were available for 136 African American (44.1%) and Hispanic (55.9%) women (mean age 50 +/- 7.3 yr). Total energy expenditure (TEE) by DLW was measured over 14 days. Physical activity energy expenditure (PAEE) was computed as 0.90 x TEE - resting metabolic rate. During week 2, participants wore an accelerometer for 7 consecutive days and completed a 7-day diary. Pearson's product-moment correlations and three statistical procedures (multiple regressions, partial correlations, and allometric scaling) were used to assess the effect of body composition on associations. The methods-comparison analysis was used to study the effect of body composition on agreement. The statistical procedures demonstrated that associations improved when body composition was included in the model. The accelerometer explained a small but meaningful portion of the variance in TEE and PAEE after body mass was accounted for. The methods-comparison analysis confirmed that agreement with DLW was affected by the transformation. Agreement between the diary (transformed with body mass) and TEE reflected the association that exists between body mass and TEE. These results suggest that the accelerometer and diary accounted for a small portion of TEE and PAEE. Most of the variance in DLW-measured energy expenditure was explained by body mass or FFM.

Estimated daily energy expenditure and blood lipids in adolescents: the Québec Family Study

PURPOSE

To examine the association between estimated daily energy expenditure and blood lipids in a sample of adolescents.

METHODS

The sample consisted of 415 males and 356 females aged 10-19 years, mainly French Canadian, recruited from the greater Quebec City area through the media as part of Phase I of the Quebec Family Study. Estimates of daily energy expenditure (DEE) were obtained with a 3-day physical activity record. Blood lipids were measured by standard procedures. The sample was stratified into three activity groups (least active, less than 25th percentile of DEE; moderately active, 25-74th percentile of DEE; and most active, 75th percentile or greater of DEE), and also by clinical cutpoints for blood lipids. Analysis of covariance, controlling for age and fatness, was conducted to compare blood lipids within gender across activity groups. Logistic regression analysis, controlling for age and fatness, was used to estimate the relative risk of being classified with an undesirable level of a blood lipid parameter on the basis of the DEE.

RESULTS

Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels were not significantly different across activity groups in males or females. High-density lipoprotein cholesterol (HDL-C) was significantly different across activity groups in males (p <.05) and females (p <.05), but the pattern of variation was different between genders. In males, the TC/HDL-C and LDL-C/HDL-C ratios decreased between the moderately active and most active groups (p <.05). Significant differences remained when subcutaneous fatness was considered as a covariate. The results from logistic regression analysis indicated that the odds ratios for low HDL-C levels was significant only in low DEE girls (odds ratio 2.83) compared with high DEE girls.

CONCLUSIONS

The results suggest that increased energy expenditure and physical activity are associated with higher levels of HDL-C in adolescents of both sexes.

Measuring energy expenditure in habitually active and sedentary pregnant women

PURPOSE

To describe patterns of energy expenditure (EE) during pregnancy and to assess the convergent validity of three methods of estimating EE.

METHODS

We administered heart rate (HR) telemetry, accelerometry, and a physical activity record (PAR) over two consecutive days at weeks 20 and 32 of pregnancy and 12 wk postpartum to 28 habitually active and 28 habitually sedentary women.

RESULTS

Mean daily waking-time EE at 20 wk by HR telemetry was 1814 (SD 443) kcal in active women and 1738 (448) kcal in sedentary women (P > 0.50), and did not change over the period of study (for active women P > 0.40; for sedentary women P > 0.70). Compared with HR telemetry, accelerometry underestimated EE by approximately 400 kcal x d-1, and the PAR overestimated EE by a similar amount, at all time periods in both active and sedentary women. EE, expressed per unit body weight, was consistently higher for active than for sedentary women during pregnancy. Pairwise correlations between methods ranged from 0.37 to 0.90 across time periods in both active and sedentary women. Correlations were lower (range 0.07-0.81) when adjusted for the length of the recording day.

CONCLUSIONS

All methods were sensitive to variation in both the rate of EE and the duration over which activity was monitored. Accelerometry and PAR are useful methods for categorizing EE in epidemiologic studies among pregnant women but absolute estimates are biased relative to HR.

No association of sleep with total daily physical activity in normal sleepers

The aim of two studies was to examine both between-subjects and within-subjects associations between daily amounts of physical activity and sleep in the home environment. Study 1 examined self-reported exercise durations and sleep diaries for 105 consecutive days in 31 college students who were normal sleepers. Between-subjects associations of mean exercise with mean sleep were assessed with Spearman rank-order correlations. Within-subjects correlations were determined across 105 days, and by comparing sleep on the 11 most active vs. the 11 least active days. Study 2 examined 71 physically active adults (n=38 ages 18-30 years, and n=33 ages 60-75 years), the majority of whom were normal sleepers. Over seven consecutive days, physical activity was assessed via actigraphy and a diary-derived estimate of energy expenditure, and sleep was assessed via actigraphy and sleep diaries. Between-subjects associations of mean physical activity with mean sleep were assessed with partial correlations, controlling for age. Within-subjects associations were assessed with ANCOVAs, with daily physical activity serving as the covariate, and by comparing sleep on the most active vs. the least active day. No significant within-subjects associations between physical activity and sleep were found in the main analyses of either study. Two small, but significant, between-subjects correlations between different physical activity measures and subjective sleep were found in Study 2. These results fail to support epidemiologic data on the value of exercise for sleep, but are consistent with experimental evidence showing only modest effects of exercise on sleep.

The reliability and validity of the Adolescent Physical Activity Recall Questionnaire

PURPOSE

This study assessed the test-retest reliability and validity of the Adolescent Physical Activity Recall Questionnaire (APARQ) among 13- and 15-yr-old Australians.

METHODS

Two studies were conducted using the same instrument. Self-reported participation in organized and nonorganized physical activity was summarized into four measures: a three-category measure of activity, a two-category measure, and estimated energy expenditure expressed as a continuous variable and as quintiles. The reliability study (N = 226) assessed strength of agreement for all measures between responses to two administrations of the questionnaire. The validity study (N = 2026) assessed the relationship between the APARQ and performance on the Multistage Fitness Test (MFT).

RESULTS

Reliability study: for the three-category measure, percent agreement ranged 67-83% and weighted kappa ranged 0.33-0.71. For the two-category measure, percent agreement ranged 76-90% and kappa ranged 0.25-0.74. For energy expenditure expressed as a continuous variable, the intraclass correlations coefficients were generally greater than 0.6 for grade 10 students, but most were below 0.5 for grade 8 students. Validity study: for the three-category measure, mean laps were higher in the adequately and vigorously active categories than the inactive category for girls, but only the mean laps in the vigorously active and inactive categories were significantly different for boys. For the two-category measure, mean laps were higher in the active category than the inactive category for all groups. Correlations between energy expenditure and MFT laps were 0.15, 0.21, 0.14, and 0.39 for grade 8 boys, grade 8 girls, grade 10 boys, and grade 10 girls, respectively.

CONCLUSION

The APARQ has acceptable to good reliability and acceptable validity, but further validation using other methods and in other population groups is required.

Daily energy expenditure, activity patterns, and energy costs of the various activities in French 12-16-y-old adolescents in free living conditions

BACKGROUND

Changes in lifestyle and increases in sedentary activities during recent decades have been shown to contribute to the prevalence of overweight in adolescents.

OBJECTIVES

To determine the inter-individual variability and the day-to-day variations in daily energy expenditure (DEE) and activity pattern, and the energy costs and EE of the various activities of adolescents in free-living conditions.

DESIGN

Sixty adolescents (four groups of 14-16 boys or girls aged 12-16 y) participated in this cross-sectional study during spring or autumn. Activity patterns and EE were determined during five consecutive days, using both a diary and the heart rate recording method validated by whole-body calorimetry and laboratory tests.

RESULTS

Mean DEE increased significantly with age in boys, but not in girls. However, the physical activity level did not vary significantly with sex and age. Mean DEE was significantly higher in spring than in autumn in the 12.6-y-old subjects. It was also 21% higher during the free days than during the schooldays in the active subjects, but 7% lower in the sedentary subjects. The energy cost of 22 activities was determined. Time and energy devoted to moderate and sport activities exhibited great inter-individual variability. They were lower in girls than in boys and decreased with age. The increase in EE resulting from moderate and sport activities instead of sedentary activities ranged from 0.2 to 2.7 MJ/day over the week.

CONCLUSION

The great variability in DEE of adolescents resulted mainly from differences in the nature, duration and intensity of physical activities during the free days.

Familial aggregation of physical activity levels in the Québec Family Study

PURPOSE

Familial aggregation of physical activity phenotypes was investigated in 696 subjects from 200 families of the Quebec Family Study. The mean age of offspring and parents was 27 and 53 yr, respectively.

METHODS

The levels of physical activity were estimated using a 3-d diary and a questionnaire dealing with physical activity during the past year.

RESULTS

An ANOVA performed on the age and sex adjusted physical activity phenotypes revealed that there were 1.40-1.52 times more variation in physical activity levels between families than within families (0.001 < P < 0.0001), suggesting that physical activity levels aggregate in families. Maximal heritabilities (SEGPATH), adjusted for the degree of spouse resemblance, reached 25%, 16%, 19%, and 17% for the degree of inactivity, time spent in moderate to strenuous physical activities, total level of daily activity, and weekly time spent in the main activity during the previous year, respectively.

CONCLUSION

These results suggest that physical activity level is characterized by a significant degree of familial resemblance, and that inactivity has a slightly higher heritability level than moderate to strenuous physical activity or total physical activity phenotypes. The pattern of familial correlations suggests that shared familial environmental factors along with genetic factors are also important in accounting for the familial resemblance in physical activity level.

Trace element levels in whole blood and serum from Swedish adolescents

Blood and serum samples from 372 15-year-old adolescents were collected in two cities in Sweden and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The objective was to (1) determine the levels of 13 elements in blood and serum from the teenagers; and (2) for each element, investigate the correlation between the concentrations in blood and serum. The concentrations in blood and serum were generally in line with that usually reported for the essential elements Co, Cu, Zn and Se, and generally low for the 'non-essential' elements Cd, Hg, Pb. The median concentrations were in blood and serum, respectively: of Co 0.31 and 0.48 microg/l, Cu 0.92 and 1.0 mg/l, Zn 6.1 and 0.99 mg/l, Se 110 and 100 microg/l, Rb 2.8 and 0.24 mg/l, Hg 1.1 and 0.44 microg/l, Pb 16 and 0.33 microg/l. The median concentration of W in blood was <0.2 microg/l (below the detection limit) and in serum 0.087 microg/l. The median concentrations of Cd, Rh, Pd, Pt and Tl were below the detection limits. Statistically significant correlations were found between the concentrations in blood and serum for Co, Cu, Zn, Se, Rb, W, Hg and Pb. The levels presented in this study constitute baseline levels or levels generally not exceeded in adolescents for 13 elements, including essential, ubiquitous toxic, and rare elements.

Randomized controlled study of in-hospital exercise training programs in children with cystic fibrosis

The aim of this study was to compare aerobic and resistance training in children with cystic fibrosis (CF) admitted to hospital with an intercurrent pulmonary infection with a control group. The subjects were randomized into three groups on the first day of admission. The fat-free mass (FFM) was calculated, using the skin fold thickness from four sites (biceps, triceps, subscapular, and iliac crest). Pulmonary function tests were performed within 36 hr of admission and repeated on discharge from the hospital, and again at 1 month after discharge. All subjects performed an incremental treadmill exercise test, using a modified Bruce protocol. Lower limb strength was measured using a Cybex dynamometer. An assessment of quality of life was made using the Quality of Well Being Scale, as previously reported. Activity levels were measured using a 7-day activity diary, and subjects also wore an accelerometer on their hips. There were no significant differences between the three groups in terms of disease severity, and length of stay in hospital. Subjects in all three groups received intravenous antibiotics and nutritional supplementation as determined by the physician. Children randomized to the aerobic training group participated in aerobic activities for five sessions, each of 30-min duration, a week. The children randomized to the resistance training group exercised both upper and lower limbs against a graded resistance machine. Subjects in the control group received standard chest physiotherapy. Our study demonstrated that children who received aerobic training had significantly better peak aerobic capacity, activity levels, and quality of life than children who received the resistance training program. Children who received resistance training had better weight gain (total mass, as well as fat-free mass), lung function, and leg strength than children who received aerobic training. A combination of aerobic and resistance training may be the best training program, and future studies to assess optimal training programs for CF patients are indicated.