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Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval: 1.9 ± 2.9 y) to assess repeatability of TEE, and to examine if TEE adjusted for age, sex, fat-free mass, and fat mass is associated with changes in weight or body composition. Here, we report that repeatability of TEE is high for adults, but not children. Bivariate Bayesian mixed models show no among or within-individual correlation between body composition (fat mass or percentage) and unadjusted TEE in adults. For adults aged 20-60 y (N = 267; time interval: 7.4 ± 12.2 weeks), increases in adjusted TEE are associated with weight gain but not with changes in body composition; results are similar for subjects with intervals >4 weeks (N = 53; 29.1 ± 12.8 weeks). This suggests low TEE is not a risk factor for, and high TEE is not protective against, weight or body fat gain over the time intervals tested., (© 2022. The Author(s).)

To assess total daily energy expenditure (TDEE) under daily living conditions, the doubly labelled water (DLW) technique is considered the gold standard. This technique is accurate but also costly and requires specific lab equipment and expertise. It also provides an average measure of TDEE over a period of one to two weeks and hence no information on physical activity (PA) patterns is available. To overcome these shortcomings, activity monitors can be used to assess activity patterns and an estimate of TDEE can be made, provided the activity monitor has been previously validated in daily life using DLW. Most activity monitors contain accelerometers, that measure the acceleration of the body and hence represent body movement. By definition, body movement leads to energy expenditure (EE) and hence the two always need to be related. Activity monitors that provide an estimate of EE need to be validated so that the contribution of the sensor output to the prediction of EE is known. Subject characteristics such as body mass, height, gender and age already explain most of the variation of TDEE; the accelerometer should then represent the physical activity component of TDEE and improve the explained variation. Many activity monitors also contain additional sensors measuring other (physiological) output parameters such as heart rate, skin temperature, galvanic skin response or gps positioning. Although promising, so far there is no compelling evidence that these additional sensors improve the prediction of EE, so careful consideration is needed whether or not these are worth the extra cost, and the extra battery power and storage capacity needed. Again, it is important to know the individual contribution of each outcome parameter to the prediction of TDEE. In conclusion, activity monitors are valuable tools in PA research but also in nutritional research when energy balance is studied.

Background: Physical activity may be a way to increase and maintain fat-free mass (FFM) in later life, similar to the prevention of fractures by increasing peak bone mass., Objectives: A study is presented of the association between FFM and physical activity in relation to age., Methods: In a cross-sectional study, FFM was analyzed in relation to physical activity in a large participant group as compiled in the International Atomic Energy Agency Doubly Labeled Water database. The database included 2000 participants, age 3-96 y, with measurements of total energy expenditure (TEE) and resting energy expenditure (REE) to allow calculation of physical activity level (PAL = TEE/REE), and calculation of FFM from isotope dilution., Results: PAL was a main determinant of body composition at all ages. Models with age, fat mass (FM), and PAL explained 76% and 85% of the variation in FFM in females and males < 18 y old, and 32% and 47% of the variation in FFM in females and males ≥ 18 y old, respectively. In participants < 18 y old, mean FM-adjusted FFM was 1.7 kg (95% CI: 0.1, 3.2 kg) and 3.4 kg (95% CI: 1.0, 5.6 kg) higher in a very active participant with PAL = 2.0 than in a sedentary participant with PAL = 1.5, for females and males, respectively. At age 18 y, height and FM-adjusted FFM was 3.6 kg (95% CI: 2.8, 4.4 kg) and 4.4 kg (95% CI: 3.2, 5.7 kg) higher, and at age 80 y 0.7 kg (95% CI: -0.2, 1.7 kg) and 1.0 kg (95% CI: -0.1, 2.1 kg) higher, in a participant with PAL = 2.0 than in a participant with PAL = 1.5, for females and males, respectively., Conclusions: If these associations are causal, they suggest physical activity is a major determinant of body composition as reflected in peak FFM, and that a physically active lifestyle can only partly protect against loss of FFM in aging adults., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

The prevalence of overweight and obesity is on the rise around the world, not only in the West, but also in Asian countries. South Asian countries in particular are experiencing a rapid increase in overweight and obesity, that coexists with the rapid increase in non-communicable diseases linked to obesity such as diabetes and cardiovascular disease than any other country in Asia. The phenomena observed in South Asian countries are due to the size of the population, the ageing of the population, the high degree of urbanization and the lifestyle changes in favor of increased energy consumption and reduced physical activity. The imbalance between energy consumption and energy expenditure results in the development of a positive energy balance that, over time, accumulates in higher body fat. South Asians were reported to have a more unfavorable body composition with a higher percentage of body fat than Caucasians with an equivalent BMI. Body composition is a major determinant of resting energy expenditure. It has been reported that South Asians have a lower resting energy expenditure than Caucasians with the same BMI. Resting energy expenditure accounts for the majority of total daily energy expenditure and, therefore, plays a crucial role in achieving the balance between energy intake and expenditure.

Understanding the impacts of activity on energy balance is crucial. Increasing levels of activity may bring diminishing returns in energy expenditure because of compensatory responses in non-activity energy expenditures. 1-3 This suggestion has profound implications for both the evolution of metabolism and human health. It implies that a long-term increase in activity does not directly translate into an increase in total energy expenditure (TEE) because other components of TEE may decrease in response-energy compensation. We used the largest dataset compiled on adult TEE and basal energy expenditure (BEE) (n = 1,754) of people living normal lives to find that energy compensation by a typical human averages 28% due to reduced BEE; this suggests that only 72% of the extra calories we burn from additional activity translates into extra calories burned that day. Moreover, the degree of energy compensation varied considerably between people of different body compositions. This association between compensation and adiposity could be due to among-individual differences in compensation: people who compensate more may be more likely to accumulate body fat. Alternatively, the process might occur within individuals: as we get fatter, our body might compensate more strongly for the calories burned during activity, making losing fat progressively more difficult. Determining the causality of the relationship between energy compensation and adiposity will be key to improving public health strategies regarding obesity., Competing Interests: Declaration of interests The authors have no conflicts of interest to declare., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Physical activity (PA) plays an important role in the prevention of cardiovascular diseases, especially in children. Previous studies which investigated the role of PA and sedentary time (ST) in cardiovascular disease used different measurements and found inconsistent results. The current study used recommended standardized measures and provides an overview of PA and ST among Dutch primary school children and their associations with cardiovascular risk factors., Methods: 503 children (55% girls, mean age (± SD) 10 ± 1y) were included. PA (total PA, lightPA and moderate to vigorous PA (MVPA)) and ST were measured with the Actigraph GT3X accelerometer. PA in different domains was measured with the BAECKE questionnaire. Cardiovascular risk factors included BMI z-score, waist circumference, blood pressure (z-score) and estimated cardiorespiratory fitness (CRF) as measured with the 20 meter shuttle run test., Results: Children spent 57 ± 20 min/day (8%) on MVPA and 42% of the children reached the MVPA guideline of 60 min/day. Total PA and MVPA (h/day) were negatively associated with BMI z-score (B = -0.452, p = 0.011) and waist circumference (B = -3.553, p = 0.011) and positively associated with CRF (B = 2.527, p = <0.001). ST was positively associated with BMI z-score (B = 0.108, p = 0.048) and waist circumference (B = 0.920, p = 0.033). No significant associations were found between total PA or PA intensities and blood pressure., Conclusion: This study used standardized measures of PA and therefore created an accurate overview of PA, ST and their associations with cardiovascular risk factors. PA and ST were associated with BMI z-score, waist circumference and CRF. The findings emphasize the importance of promoting MVPA in children, but also highlight the potential benefits of reducing ST to improve cardiovascular risk factors., Trial Registration: ClinicalTrials.gov NCT03440580., Competing Interests: The authors have declared that no competing interests exist.

Background: Limited physical activity (PA) and a high level of sedentary time (ST) are associated with childhood obesity and are a target for intervention. This study aimed to assess objectively measured PA and ST in Dutch children across weight categories, age groups and sex., Methods: 202 children with overweight, obesity and morbid obesity (55% girls, 12 ± 3y of age, BMI z-score + 3.15 ± 0.73), referred to the Centre for Overweight Adolescents and Children's Healthcare (COACH, Maastricht UMC+) were included. PA (total PA, light PA and moderate to vigorous PA (MVPA)) and ST were measured with the GT3X Actigraph accelerometer. Wear time validation was set to include at least four days, 480 min/day, including one weekend day., Results: PA levels in children with morbid obesity were higher compared to children with obesity, also after correction for age and sex (corrected difference (B) 118 counts per minute (cpm), p = .006). ST was lower in children with morbid obesity compared to children with obesity (B - 51 min/day, p = .018). Girls performed significantly less MVPA than boys (B - 11 min/day, p < .001) and for each year increase of age, children performed less PA (B - 46 cpm, p < .001) and ST increased (B 18 min/day, p < .001)., Conclusion: PA and ST is different in subgroups of children with overweight, obesity and morbid obesity, depending on sex, age and overweight severity. In particular, children with obesity perform less PA and more ST compared to children with morbid obesity. Future research could explore the preferences and needs for PA and ST in children in the different weight categories., Trial Registration: The trial is registered with Clinicaltrials.gov NCT02091544 at March 19, 2014., (© 2021. The Author(s).)

Total daily energy expenditure ("total expenditure") reflects daily energy needs and is a critical variable in human health and physiology, but its trajectory over the life course is poorly studied. We analyzed a large, diverse database of total expenditure measured by the doubly labeled water method for males and females aged 8 days to 95 years. Total expenditure increased with fat-free mass in a power-law manner, with four distinct life stages. Fat-free mass-adjusted expenditure accelerates rapidly in neonates to ~50% above adult values at ~1 year; declines slowly to adult levels by ~20 years; remains stable in adulthood (20 to 60 years), even during pregnancy; then declines in older adults. These changes shed light on human development and aging and should help shape nutrition and health strategies across the life span., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Persons with multiple sclerosis (pwMS) experience walking impairments, characterized by decreased walking speeds. In healthy subjects, the self-selected walking speed is the energetically most optimal. In pwMS, the energetically most optimal walking speed remains underexposed. Therefore, this review aimed to determine the relationship between walking speed and energetic cost of walking (Cw) in pwMS, compared with healthy subjects, thereby assessing the walking speed with the lowest energetic cost. As it is unclear whether the Cw in pwMS differs between overground and treadmill walking, as reported in healthy subjects, a second review aim was to compare both conditions., Method: PubMed and Web of Science were systematically searched. Studies assessing pwMS, reporting walking speed (converted to meters per second), and reporting oxygen consumption were included. Study quality was assessed with a modified National Heart, Lung and Blood Institute checklist. The relationship between Cw and walking speed was calculated with a second-order polynomial function and compared between groups and conditions., Results: Twenty-nine studies were included (n = 1535 pwMS) of which 8 included healthy subjects (n = 179 healthy subjects). PwMS showed a similar energetically most optimal walking speed of 1.44 m/s with a Cw of 0.16, compared with 0.14 mL O 2 /kg/m in healthy subjects. The most optimal walking speed in treadmill was 1.48 m/s, compared with 1.28 m/s in overground walking with a similar Cw., Conclusion: Overall, the Cw is elevated in pwMS but with a similar energetically most optimal walking speed, compared with healthy subjects. Treadmill walking showed a similar most optimal Cw but a higher speed, compared with overground walking.

The aim of this study was to investigate whether VO 2 max can be accurately measured in a respiration chamber. Thirty participants aged 23.4 ± 3.9 years with a wide range in VO 2 max were included. Participants performed four incremental cycle ergometer tests (VO 2 max) with a minimum of 5 days between tests. These tests consisted of one familiarization test with face mask, followed by two VO 2 max tests in the respiration chamber and one test with face mask in randomized order. Oxygen consumption and CO 2 production were measured continuously using Omnical (Maastricht University, the Netherlands) gas analysis system. The mean VO 2 max was 3634 ± 766 ml, which resulted in mean VO 2 max per lean body mass of 60.8 ± 8.0 ml/kg. Repeated respiration chamber tests showed a high concordance, and no significant differences were detected between tests (Lin's concordance correlation coefficient (Rc) = 0.99; ∆70 ± 302 ml/min; p = .38). There was high concordance between the mean VO 2 max from both respiration chamber tests and the mean face mask tests, and no significant difference (Rc = 0.99; ∆41 ± 173 ml/min; p = .22) was observed. The Bland-Altman plots showed no proportional bias between different tests. In conclusion, the respiration chamber has been found to be a valid and reproducible method for measuring VO 2 max. New research opportunities are possible in the respiration chamber, such as maximal exercise testing during 24-hour measurements., (© 2021 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The estimated rCO 2 is sensitive to the dilution space ratio (DSR) of the two isotopes. Based on performance in validation studies, we propose a new equation based on a new estimate of the mean DSR. The DSR is lower at low body masses (<10 kg). Using data for 1,021 babies and infants, we show that the DSR varies non-linearly with body mass between 0 and 10 kg. Using this relationship to predict DSR from weight provides an equation for rCO 2 over this size range that agrees well with indirect calorimetry (average difference 0.64%; SD = 12.2%). We propose adoption of these equations in future studies., Competing Interests: The authors declare no competing interests., (© 2021 The Authors.)

Background: Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea., Objective: The goal was to assess the impact of BLVR on energy balance regulation., Design: Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated., Results: Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (-2,430, -540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m2). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, p = 0.019)., Conclusions: Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. Clinical Trial Registry Number: NCT02500004 at www.clinicaltrial.gov., (© 2021 The Author(s) Published by S. Karger AG, Basel.)

Background: Despite the well-known beneficial health effects of physical activity (PA), the majority of Dutch primary school children do not meet the recommended PA guidelines. Although there is growing evidence on the effectiveness of exergames for PA in children, there is limited evidence on their effect on health outcomes, such as cardiovascular health and health-related quality of life (HRQOL), and on factors influencing their effectiveness and feasibility. The exergame BOOSTH uses a wrist-worn activity tracker to measure steps per day. As a reward for the performed PA, children can unlock levels in the online BOOSTH game. In addition, "BOOSTH battle" enables competition between groups., Objective: This protocol describes a cluster randomized controlled trial in 16 primary schools in the Netherlands investigating the effect of BOOSTH on moderate-to-vigorous PA (MVPA) using accelerometry. Secondary aims are to investigate the feasibility of BOOSTH (mixed methods: questionnaires and focus group interviews) and its effect on cardiovascular risk factors (anthropometrics, blood pressure, and retinal microvasculature) and HRQOL., Methods: Stratification variables and relevant variables related to outcomes (such as BMI [z-score], sex, age, and parenting style) and/or missingness will be taken into account. Measurements will be performed at baseline and after 3, 6, and 12 months., Results: The study has received funding from Province Limburg (SAS-2015-04956) and received ethical approval from the Medical Ethics Committee of Maastricht University Medical Centre (METC172043/NL64324.068.17). The results of the analyses are expected to be published in 2021., Conclusions: With this study, the ability of the exergame BOOSTH to increase PA and improve health in children of primary school age will be investigated. The insights into effectiveness and feasibility will result in scientific and societal recommendations, which could potentially contribute to widespread implementation of exergames for children., Trial Registration: ClinicalTrials.gov NCT03440580; https://clinicaltrials.gov/ct2/show/NCT03440580., International Registered Report Identifier (irrid): DERR1-10.2196/24035., (©Gabrielle ten Velde, Guy Plasqui, Maartje Willeboordse, Bjorn Winkens, Anita Vreugdenhil. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 11.12.2020.)

Objectives: To examine the bidirectional association of sleep duration with proportions of time spent in physical behaviors among Dutch adolescents., Methods: Adolescents ( n = 294, 11-15 years) completed sleep diaries and wore an accelerometer (ActiGraph) over 1 week. With linear mixed-effects models, the authors estimated the association of sleep categories (short, optimal, and long) with the following day's proportion in physical behaviors. With generalized linear mixed models with binomial distribution, the authors estimated the association of physical behavior proportions on sleep categories. Physical behavior proportions were operationalized using percentages of wearing time and by applying a compositional approach. All analyses were stratified by gender accounting for differing developmental stages., Results: For males (number of observed days: 345, n = 83), short as compared with optimal sleep was associated with the following day's proportion spent in sedentary (-2.57%, p = .03, 95% confidence interval [CI] [-4.95, -0.19]) and light-intensity activities (1.96%, p = .02, 95% CI [0.27, 3.65]), which was not significant in the compositional approach models. Among females (number of observed days: 427, n = 104), long sleep was associated with the proportions spent in moderate- to vigorous-intensity physical activity (1.69%, p < .001, 95% CI [0.75, 2.64]) and in sedentary behavior (-3.02%, p < .01, 95% CI [-5.09, -0.96]), which was replicated by the compositional approach models. None of the associations between daytime activity and sleep were significant (number of obs.: 844, n = 204)., Conclusions: Results indicate partial associations between sleep and the following day's physical behaviors, and no associations between physical behaviors and the following night's sleep.

Whole-room indirect calorimeters have been used to study human metabolism for more than a century. These studies have contributed substantial knowledge to the assessment of nutritional needs and the regulation of energy expenditure and substrate oxidation in humans. However, comparing results from studies conducted at different sites is challenging because of a lack of consistency in reporting technical performance, study design, and results. In May 2019, an expert panel was convened to consider minimal requirements for conducting and reporting the results of human whole-room indirect calorimeter studies. We propose Room Indirect Calorimetry Operating and Reporting Standards, version 1.0 (RICORS 1.0) to provide guidance to ensure consistency and facilitate meaningful comparisons of human energy metabolism studies across publications, laboratories, and clinical sites., (© 2020 The Obesity Society.)

Background: Since desk-dominated work environments facilitate sedentary behavior, office workers sit for 66% of their working days and only 8% succeed in interrupting their prolonged periods of sitting within the first 55 minutes. Yet stretches of long and uninterrupted sitting increase the likelihood of several chronic metabolic and cardiovascular diseases., Objective: We therefore developed a computer-based app designed to interrupt periods of prolonged sitting among office employees., Methods: When developing the intervention, we applied the intervention mapping protocol. This approach for the systematic design of theory and evidence-based behavior change programs consists of 6 steps: creation of a logic model of the problem, creation of a logic model of change, program design, program production, design of an implementation plan, and development of an evaluation plan., Results: Working through all 6 steps has resulted in an individually adaptable intervention to reduce sedentary behavior at work. The intervention, UPcomplish, consists of tailored, half-automatized motivational components delivered by a coach. To register sedentary behavior, the VitaBit (VitaBit Software International BV) toolkit, a wearable accelerometry-based monitoring device, is used. Among others, UPcomplish includes personalized goal setting, tailored suggestions to overcome hurdles, and weekly challenges. The VitaBit toolkit supports the participants to monitor their behavior in relation to self-set goals., Conclusions: Intervention mapping is a useful protocol not only for the systematic development of a comprehensive intervention to reduce sedentary behavior but also for planning program adherence, program implementation, and program maintenance. It facilitates obtaining the participation of relevant stakeholders at different ecological levels in the development process of the intervention and anticipating facilitators to and barriers of program implementation and maintenance., Trial Registration: Netherlands Trial Register NL7503; https://www.trialregister.nl/trial/7503., (©Nathalie M Berninger, Gill A ten Hoor, Guy Plasqui, Gerjo Kok, Gjalt-Jorn Ygram Peters, Robert A C Ruiter. Originally published in JMIR Formative Research (http://formative.jmir.org), 20.07.2020.)

Low cardiorespiratory fitness (CRF) increases risk of all-cause mortality and cardiovascular events. Periodic CRF assessment can have an important preventive function. The objective of this study was to develop a protocol-free method to estimate CRF in daily life based on heart rate (HR) and body acceleration measurements. Acceleration and HR data were collected from 37 subjects (men = 49%) while they performed a standardized laboratory activity protocol (sitting, walking, running, cycling) and during a 5-day free-living monitoring period. CRF was determined by oxygen uptake (V̇o 2max ) during maximal exercise testing. A doubly labeled water-validated equation was used to predict total energy expenditure (TEE) from acceleration data. A fitness index was defined as the ratio between TEE and HR (TEE-pulse). Activity recognition techniques were used to process acceleration features and classify sedentary, ambulatory, and other activity types. Regression equations based on TEE-pulse data from each activity type were developed to predict V̇o 2max . TEE-pulse measured within each activity type of the laboratory protocol was highly correlated with V̇o 2max ( r from 0.74-0.91). Averaging the outcome of each activity-type specific equation based on TEE-pulse from the laboratory data led to accurate estimates of V̇o 2max [root mean square error (RMSE): 300 mL O 2 /min, or 10%]. The difference between laboratory and free-living determined TEE-pulse was 3.7 ± 11% ( r  = 0.85). The prediction method preserved the prediction accuracy when applied to free-living data (RMSE: 367 mL O 2 /min, or 12%). Measurements of body acceleration and HR can be used to predict V̇o 2max in daily life. Activity-specific prediction equations are needed to achieve highly accurate estimates of CRF. NEW & NOTEWORTHY This is among the very few studies validating, in free-living conditions, a method to estimate cardiorespiratory fitness using heart rate and body acceleration data. A novel parameter called TEE-pulse, which was defined as the ratio between accelerometer-determined energy expenditure and heart rate, was highly correlated with maximal oxygen uptake (V̇o 2max ). Activity classification and the use of activity-selective prediction equations outperformed previously published methods for estimating V̇o 2max from heart rate and acceleration data.

The present study was designed to objectively assess the effects of 3-months submarine deployment on behavioural and metabolic determinants of metabolic health. In 13 healthy, non-obese volunteers, we using stable isotope dilution, and plasma and urinary biochemistry to characterize metabolic health before and after a 3-month submarine deployment. Volunteers worked in 6-h shifts. After deployment, we observed reduced fat-free mass (mean ± SD, -4.1 ± 3.3 kg, p = 0.003) and increased adiposity (21.9 ± 3.2% fat mass to 24.4 ± 4.7%, p = 0.01). Changes in fat-free mass were positively associated with physical activity (+0.8 kg per 0.1 increase in PAL, p = 0.03). The average physical activity level was 1.64 ± 0.26 and total energy expenditure during deployment was 2937 ± 498 kcal/d, while energy intake was 3158 ± 786 kcal/d. Fasting glucose ( p = 0.03), and triglycerides ( p = 0.01) declined, whereas fasting free fatty acids increased ( p = 0.04). Plasma vitamin D and B12 concentrations decreased (-14%, p = 0.04, and -44%, p = 0.001, respectively), and plasma calcium, and magnesium increased (+51%, p = 0.01, and +5%, p = 0.02). Haemoglobin was unchanged, but haematocrit decreased (-2.2 ± 2.1%, p = 0.005). In conclusion, submarine deployment impairs fat-free mass maintenance and promotes adiposity. High physical activity may prevent the decline in fat-free mass. Our study confirms the need to counteract Vitamin D and B12 deficiencies, and suggests impairments in erythrocyte metabolism., Competing Interests: The authors declare no conflict of interest.

Background: For the same BMI, South Asians have a higher body fat percentage, a higher liver fat content and a more adverse metabolic profile than whites. South Asians may have a lower fat oxidation than whites, which could result in an unfavorable metabolic profile when exposed to increased high-fat foods consumption and decreased physical activity as in current modern lifestyle., Objective: To determine substrate partitioning, liver fat accumulation and metabolic profile in South Asian and white men in response to overfeeding with high-fat diet under sedentary conditions in a respiration chamber., Design: Ten South Asian men (BMI, 18-29 kg/m 2 ) and 10 white men (BMI, 22-33 kg/m 2 ), matched for body fat percentage, aged 20-40 year were included. A weight maintenance diet (30% fat, 55% carbohydrate, and 15% protein) was given for 3 days. Thereafter, a baseline measurement of liver fat content (1H-MRS) and blood parameters was performed. Subsequently, subjects were overfed (150% energy requirement) with a high-fat diet (60% fat, 25% carbohydrate, and 15% protein) over 3 consecutive days while staying in a respiration chamber mimicking a sedentary lifestyle. Energy expenditure and substrate use were measured for 3 × 24-h. Liver fat and blood parameters were measured again after the subjects left the chamber., Results: The 24-h fat oxidation as a percentage of total energy expenditure did not differ between ethnicities (P = 0.30). Overfeeding increased liver fat content (P = 0.02), but the increase did not differ between ethnicities (P = 0.64). In South Asians, overfeeding tended to increase LDL-cholesterol (P = 0.08), tended to decrease glucose clearance (P = 0.06) and tended to elevate insulin response (P = 0.07) slightly more than whites., Conclusions: Despite a similar substrate partitioning and similar accretion of liver fat, overfeeding with high-fat under sedentary conditions tended to have more adverse effects on the lipid profile and insulin sensitivity in South Asians.

Selecting effective dietary strategies for professional football players requires comprehensive information on their energy expenditure (EE) and dietary intake. This observational study aimed to assess EE and dietary intake over a 14-day period in a representative group (n = 41) of professional football players playing in the Dutch Premier League (Eredivisie). Daily EE, as assessed by doubly labelled water, was 13.8 ± 1.5 MJ/day, representing a physical activity level (PAL) of 1.75 ± 0.13. Weighted mean energy intake (EI), as assessed by three face-to-face 24-h recalls, was 11.1 ± 2.9 MJ/day, indicating 18 ± 15% underreporting of EI. Daily EI was higher on match days (13.1 ± 4.1 MJ) compared with training (11.1 ± 3.4 MJ; P < 0.01) and rest days (10.5 ± 3.1 MJ; P < 0.001). Daily carbohydrate intake was significantly higher during match days (5.1 ± 1.7 g/kg body mass (BM)) compared with training (3.9 ± 1.5 g/kg BM; P < 0.001) and rest days (3.7 ± 1.4 g/kg BM; P < 0.001). Weighted mean protein intake was 1.7 ± 0.5 g/kg BM. Daytime distribution of protein intake was skewed, with lowest intakes at breakfast and highest at dinner. In conclusion, daily EE and PAL of professional football players are modest. Daily carbohydrate intake should be increased to maximize performance and recovery. Daily protein intake seems more than adequate, but could be distributed more evenly throughout the day.

For the same BMI, South Asians have a higher body fat percentage than Caucasians. There might be differences in the fatty acid (FA) handling in adipose tissue when both ethnicities are exposed to high-fat overfeeding. The objective of the present study was to investigate the molecular adaptation in relation to FA metabolism in response to overfeeding with a high-fat diet (OHFD) in South Asian and Caucasian men. Ten South Asian men (BMI 18-29 kg/m2) and ten Caucasian men (BMI 22-33 kg/m2), matched for body fat percentage, aged 20-40 years were included. A weight-maintenance diet (30 % fat, 55 % carbohydrate and 15 % protein) was given for 3 d followed by 3 d of overfeeding (150 % energy requirement) with a high-fat diet (60 % fat, 25 % carbohydrate and 15 % protein) while staying in a respiration chamber. Before and after overfeeding, abdominal subcutaneous fat biopsies were taken. Proteins were isolated, analysed and quantified for short-chain 3-hydroxyacyl-CoA dehydrogenase (HADH), carnitine palmitoyl-transferase 1α (CPT1a), adipose TAG lipase, perilipin A (PLINA), perilipin B, lipoprotein lipase and fatty acid binding protein 4 using Western blotting. OHFD decreased the HADH level (P < 0·05) in Caucasians more than in Asians (P < 0·05), but the baseline and after intervention HADH level was relatively higher in Caucasians. The level of CPT1a decreased in South Asians and increased in Caucasians (P < 0·05). PLINA did not change with diet but the level was higher in South Asians (P < 0·05). The observed differences in HADH and PLINA levels as well as in CPT1a response may be important for differences in the long-term regulation of energy (fat) metabolism in these populations.

Purpose: Little data are available on doubly labeled water (DLW) assessed total daily energy expenditure (TDEE) during extreme endurance exercise. Doubly labeled water is considered the gold standard to measure TDEE, but different calculations are being used, which may have a large impact on the results. The aim of the current study was to measure TDEE during the Giro d'Italia and apply two different calculation methods., Methods: Seven male cyclists (age, 28 ± 5 yr; body mass index, 22.1 ± 2.1 kg·m) completed the 24-d professional cycling race "Giro d'Italia" in which a total distance of 3445 km was covered, including 10 mountain stages. Total daily energy expenditure was measured over the entire duration of the race, with the ingestion of DLW at three different time points. To calculate TDEE and body composition, the isotope dilution space was calculated using two different techniques, the "plateau" and "intercept" technique., Results: The %fat mass at baseline was 7.8% and 16.8% with the plateau and intercept technique respectively and did not significantly change over the course of the race. Total daily energy expenditure was on average 32.3 ± 3.4 MJ·d using the plateau technique versus 28.9 ± 3.2 using the intercept technique, resulting in an average physical activity level (PAL) of 4.37 ± 0.43 versus 3.91 ± 0.39, respectively. The dilution space ratio was on average 1.030 with the plateau and 1.060 with the intercept technique., Conclusions: Given that the observed dilution space ratio with the plateau technique is similar as the expected ratio from literature and the % fat mass of 7.8% is more realistic for the athletes being studied, we propose the application of the plateau rather than the intercept method, when using DLW during extreme endurance exercise.

Background and Aim: Increasing energy expenditure is an effective strategy for the prevention of obesity. In this respect, Lycium barbarum (goji berry) is of interest, as it has been shown to increase postprandial oxygen consumption. Although this suggests that energy expenditure was also increased, energy expenditure and substrate oxidation can only be assessed accurately when both oxygen consumption and carbon dioxide production are measured. We therefore investigated the effects of a single dose of Lycium barbarum fruit on postprandial energy expenditure and substrate oxidation in a randomized, double-blind crossover trial. In addition, markers of lipid and glucose metabolism were measured., Methods: Seventeen healthy, overweight men received in a random order a meal containing 25 grams of dried Lycium barbarum fruit or a control meal matched for caloric content and macronutrient composition. Energy expenditure and the respiratory quotient were determined using indirect calorimetry before and up to 4 hours after meal intake. Blood was sampled before and after meal intake at regular intervals for analyses of plasma glucose, serum triacylglycerol, and free fatty acid concentrations., Results: Energy expenditure significantly increased after the Lycium barbarum and control meal, but no differences were found between the meals ( p =0.217). Postprandial changes in respiratory quotient ( p =0.719) and concentrations of glucose ( p =0.663), triacylglycerol ( p =0.391), and free fatty acids ( p =0.287) were also not affected by Lycium barbarum intake., Conclusions: A single dose of Lycium barbarum does not affect postprandial energy expenditure, substrate oxidation, and markers for lipid and glucose metabolism in healthy, overweight men.

Purpose: The effects of growth hormone (GH) treatment on linear growth and body composition have been studied extensively. Little is known about the GH effect on energy expenditure (EE). The aim of this study was to investigate the effects of GH treatment on EE in children, and to study whether the changes in EE can predict the height gain after 1 year., Methods: Total EE (TEE), basal metabolic rate (BMR), and physical activity level (PAL) measurements before and after 6 weeks of GH treatment were performed in 18 prepubertal children (5 girls, 13 boys) born small for gestational age (n = 14) or with growth hormone deficiency (n = 4) who were eligible for GH treatment. TEE was measured with the doubly labelled water method, BMR was measured with an open-circuit ventilated hood system, PAL was assessed using an accelerometer for movement registration and calculated (PAL = TEE/BMR), activity related EE (AEE) was calculated [AEE = (0.9 × TEE) - BMR]. Height measurements at start and after 1 year of GH treatment were analysed. This is a 1-year longitudinal intervention study, without a control group for comparison., Results: BMR and TEE increased significantly (resp. 5% and 7%). Physical activity (counts/day), PAL, and AEE did not change. 11 out of 13 patients (85%) with an increased TEE after 6 weeks of GH treatment had a good first-year growth response (∆height SDS > 0.5)., Conclusions: GH treatment showed a positive effect on EE in prepubertal children after 6 weeks. No effect on physical activity was observed. The increase in TEE appeared to be valuable for the prediction of good first-year growth responders to GH treatment.

This study aimed to analyze the intra-individual variation in VO 2max of human subjects using total-capture and free-flow indirect calorimetry. Twenty-seven men (27 ± 5 year; VO 2max 49-79 mL•kg -1 •min -1 ) performed two maximal exertion tests (CPETs) on a cycle ergometer, separated by a 7 ± 2 day interval. VO 2 and VCO 2 were assessed using an indirect calorimeter (Omnical) with total capture of exhalation in a free-flow airstream. Thirteen subjects performed a third maximal exertion test using a breath-by-breath calorimeter (Oxycon Pro). On-site validation was deemed a requirement. For the Omnical, the mean within-subject CV for VO 2max was 1.2 ± 0.9% (0.0%-4.4%) and for ergometer workload P max 1.3 ± 1.3% (0%-4.6%). VO 2max values with the Oxycon Pro were significantly lower in comparison with Omnical (P < 0.001; t test) with mean 3570 vs 4061 and difference SD 361 mL•min -1 . Validation results for the Omnical with methanol combustion were -0.05 ± 0.70% (mean ± SD; n = 31) at the 225 mL•min -1 VO 2 level and -0.23 ± 0.80% (n = 31) at the 150 mL•min -1 VCO 2 level. Results using gas infusion were 0.04 ± 0.75% (n = 34) and -0.99 ± 1.05% (n = 24) over the respective 500-6000 mL•min -1 VO 2 and VCO 2 ranges. Validation results for the Oxycon Pro in breath-by-breath mode were - 2.2 ± 1.6% (n = 12) for VO 2 and 5.7 ± 3.3% (n = 12) for VCO 2 over the 1000-4000 mL•min -1 range. On a Visual analog scale, participants reported improved breathing using the free-flow indirect calorimetry (score 7.6 ± 1.2 vs 5.1 ± 2.7, P = 0.008). We conclude that total capturing free-flow indirect calorimetry is suitable for measuring VO 2 even with the highest range. VO 2max was linear with the incline in P max over the full range., (© 2018 The Authors. Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.)

Objective: Participation in society of persons with chronic diseases receives increasing attention. However, little is known about which components of participation are most relevant to life satisfaction. This study examines the association between several aspects of social role participation and satisfaction with life (SWL) in patients with ankylosing spondylitis (AS) compared to population controls., Methods: In a cross-sectional study, participants completed the Social Role Participation Questionnaire (SRPQ) and SWL scale. The SRPQ assesses several dimensions of participation (importance, satisfaction with performance, and satisfaction with time and physical difficulty) in 11 roles representing 3 domains (interpersonal relations, leisure, and work). For individuals with AS and controls, the association between role domains and SWL was examined using linear regression for each participation dimension separately, in the total and the employed population, adjusting for age, sex, education, and income., Results: A total of 246 AS patients (mean ± SD age 51 ± 12 years, 62% males, mean ± SD disease duration 17 ± 12 years) and 510 controls (mean ± SD age 42 ± 15 years, 70% males) were included. AS patients were more frequently (extremely) dissatisfied with life (17.9% versus 8.6%; P < 0.05). In the total and the employed population, less physical difficulty and higher satisfaction with interpersonal relations and leisure were associated with higher SWL, and this was somewhat stronger in patients than in controls (P < 0.1). In employed controls, but not in employed patients, satisfaction with work was independently associated with SWL., Conclusion: These findings highlight the importance of supporting persons with AS in ameliorating social role participation, particularly in areas like close relationships and leisure activities, which are typically ignored when treating AS., (© 2017, American College of Rheumatology.)

Sedentary behavior (SB) has detrimental consequences and cannot be compensated for through moderate-to-vigorous physical activity (PA). In order to understand and mitigate SB, tools for measuring and monitoring SB are essential. While current direct-to-customer wearables focus on PA, the VitaBit validated in this study was developed to focus on SB. It was tested in a laboratory and in a free-living condition, comparing it to direct observation and to a current best-practice device, the ActiGraph, on a minute-by-minute basis. In the laboratory, the VitaBit yielded specificity and negative predictive rates (NPR) of above 91.2% for sitting and standing, while sensitivity and precision ranged from 74.6% to 85.7%. For walking, all performance values exceeded 97.3%. In the free-living condition, the device revealed performance of over 72.6% for sitting with the ActiGraph as criterion. While sensitivity and precision for standing and walking ranged from 48.2% to 68.7%, specificity and NPR exceeded 83.9%. According to the laboratory findings, high performance for sitting, standing, and walking makes the VitaBit eligible for SB monitoring. As the results are not transferrable to daily life activities, a direct observation study in a free-living setting is recommended., Competing Interests: Nathalie Berninger is employed by VitaBit to further validate the device and to develop a sedentary behavior intervention. However, apart from providing the devices and access to the software and the raw data for the current study, VitaBit had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Background: In this study, the main hypothesis is that heavier people enjoy strength exercises more than normal-weight people, mediated by fat-free mass and muscle strength. Further, it is hypothesized that heavier people are better in strength exercises and enjoy strength exercises more compared to aerobic exercises., Methods: In a cross-sectional study, height, weight, body composition (i.e., fat mass and fat-free mass by underwater weighing), muscle strength (i.e., one-repetition maximal strength for the leg press and chest press), maximal aerobic exertion (VO 2 max) during cycle ergometry, and psychological determinants (i.e., attitudes, intentions, and self-determined motivations for strength exercises and aerobic exercises using questionnaires) were measured in 68 participants (18-30 years)., Results: Significant correlations between weight/BMI and fat-free mass (index) (r values = .70-.80, p values < .001), fat-free mass and muscle strength (r values = .35-.55, p values < .05), and muscle strength and attitudes, intentions, and motivation for strength exercises were found (r values = .29-.43, p values < .05); BMI was related to psychological determinants via fat-free mass and muscle strength. Furthermore, participants with a higher BMI are significantly better in strength exercises, more intrinsically motivated, and less motivated to do strength exercises compared to aerobic exercises (all p values < .05). Trends in the same direction were found for the following variables: instrumental attitude, experiential attitude, and intention (p values < .1)., Conclusions: Strength exercises could be more appropriate for heavier people and might therefore be a valuable component in physical activity programs for people who are overweight or obese.

When the doubly labeled water (DLW) method is used to measure total daily energy expenditure (TDEE), isotope measurements are typically performed using isotope ratio mass spectrometry (IRMS). New technologies, such as off-axis integrated cavity output spectroscopy (OA-ICOS) provide comparable isotopic measurements of standard waters and human urine samples, but the accuracy of carbon dioxide production (V̇co 2 ) determined with OA-ICOS has not been demonstrated. We compared simultaneous measurement V̇co 2 obtained using whole-room indirect calorimetry (IC) with DLW-based measurements from IRMS and OA-ICOS. Seventeen subjects (10 female; 22 to 63 yr) were studied for 7 consecutive days in the IC. Subjects consumed a dose of 0.25 g H 2 O (98% APE) and 0.14 g 18 O (98% APE) and 0.14 g 2 H 2 O (99.8% APE) per kilogram of total body water, and urine samples were obtained on days 1 and 8 to measure average daily V̇co 2 using OA-ICOS and IRMS. V̇co 2 was calculated using both the plateau and intercept methods. There were no differences in V̇co 2 measured by OA-ICOS or IRMS compared with IC when the plateau method was used. When the intercept method was used, V̇co 2 using OA-ICOS did not differ from IC, but V̇co 2 measured using IRMS was significantly lower than IC. Accuracy (~1-5%), precision (~8%), intraclass correlation coefficients ( R = 0.87-90), and root mean squared error (30-40 liters/day) of V̇co 2 measured by OA-ICOS and IRMS were similar. Both OA-ICOS and IRMS produced measurements of V̇co 2 with comparable accuracy and precision compared with IC.

Overweight and obesity in children and adolescents is seen as a global health challenge and a priority for prevention (1). To solve such a health issue, we need full understanding of the related health behaviors (and underlying beliefs), and understanding of the biological mechanisms that cause or can prevent the issue. However, for overweight and obesity, drawing a full picture of the exact problem (and the subsequent solution) is difficult. In this paper, we describe how we used Intervention Mapping to develop a theory and evidence-based prevention program targeting overweight and obesity and how we investigated the 1-year efficacy of this program on body composition and physical activity of adolescents. A helpful tool, theoretical, and methodological lessons learned are given from our attempt to contribute to solving the obesity problem.

Background: Overweightness and obesity represent a high burden on well-being and society. Strength training has positive effects on body composition and metabolic health for people who are overweight or obese. The evidence for psychological effects of strength exercises is unclear., Objective: The aim of this study was to assess the psychological effects of strength exercises for people who are overweight or obese., Methods: Relevant literature was identified by use of the PubMed and PsycINFO databases. For each study, effect sizes and corresponding variance estimates were extracted or calculated for the main effects of strength exercises on psychological outcomes., Results: Seventeen studies were included. There was almost no overlap among the various measures of psychological constructs. The constructs were ordered into eight broad categories. Meta-analytical techniques revealed substantial heterogeneity in effect sizes, and combined with the low number of effect size estimates for each outcome measure, this precluded meta-analysis. Organization of the data showed that the evidence base so far does not show convincing effects of strength training on psychological outcome measures. Some weak effects emerged on self-efficacy, self-esteem, inhibition, and psychological disorders (e.g., anxiety and depression). No additional or comparable effects to other interventions were found for mood, outcome expectations, quality of life, and stress., Discussion: The main finding of this review is that despite a strong theoretical basis for expecting positive effects of strength training on psychological outcomes, the literature shows a large gap in this area. The existing research does not show a clear picture: some positive results might exist, but there is a strong need to accumulate more evidence before drawing conclusions.

Rationale: The development of evidence-based treatment guidelines for pediatric pulmonary arterial hypertension (PAH) is hampered by lack of pediatric clinical trials. Trial design is hampered by lack of a feasible clinical endpoint in this population., Objectives: To evaluate the use of accelerometry for measuring physical activity (PA) in pediatric PAH and to investigate its correlation with clinical disease severity markers., Methods: We included children from the Dutch National Network for Pediatric Pulmonary Hypertension. Control patients were recruited from the outpatient cardiology clinic of the Beatrix Children's Hospital. Children were asked to wear the accelerometer for 7 days. Vector magnitude counts per minute (VM CPM) and time per day spent in different PA intensity levels were defined as accelerometer outcomes., Measurements and Main Results: VM CPM was lower in children with PAH (n = 29) than in controls (n = 60; 647 vs. 921; P < 0.001). Children with PAH spent less time in moderate and vigorous PA (13 vs. 29 min/d and 2 vs. 13 min/d, respectively; P < 0.001). Time spent in moderate and vigorous PA correlated inversely with World Health Organization functional class. Time spent in moderate PA correlated positively with 6-minute-walk distance. In post hoc analyses, VM CPM and time spent in moderate/vigorous combined and vigorous PA were associated with outcome (P ≤ 0.044)., Conclusions: PA is markedly decreased in children with PAH. Accelerometer output correlated with clinical disease severity markers and may predict outcome. We showed an exciting potential of PA as a meaningful endpoint for clinical trials in pediatric PAH, although its clinical utility and prognostic value need to be further validated.

Objective: Participation in social roles for persons with chronic disease is important for their quality of life, but interpretation of the data on participation is difficult in the absence of a benchmark. This study aimed to compare social role participation in patients with ankylosing spondylitis (AS) to population controls using the Social Role Participation Questionnaire (SRPQ)., Methods: There were 246 AS patients and 510 population controls who completed the SRPQ, which assesses participation in 11 roles (with scores ranging 1-5) across 4 dimensions (importance, satisfaction with performance, satisfaction with time, and physical difficulty), and additionally ranked their 3 most important roles. The ranking of role importance, the SRPQ dimension scores, and the gap between importance and satisfaction with performance of roles were compared between patients and controls., Results: Patients (62% male; mean ± SD age 51 ± 12 years) and controls (70% male; mean ± SD 42 ± 15 years) ranked intimate relationships, relationships with children/stepchildren/grandchildren, and employment as the most important roles. Compared to controls, patients gave higher scores on the SRPQ to importance (3.75 versus 3.43), but reported lower satisfaction with performance (3.19 versus 3.58) and greater physical difficulty (3.87 versus 4.67) (P ≤ 0.05 for all). The largest differences in gaps between importance and satisfaction with performance for patients compared to controls were seen in the physical leisure, hobbies, and traveling and vacation categories, in which patients assigned higher importance but reported especially low satisfaction., Conclusion: As society places increasing emphasis on individual responsibility to participate fully in social roles, the current data suggest that health care providers should pay more attention to participation restrictions experienced by patients with AS., (© 2016, American College of Rheumatology.)

In this work, we propose to use pattern recognition methods to determine submaximal heart rate (HR) during specific contexts, such as walking at a certain speed, using wearable sensors in free living, and using context-specific HR to estimate cardiorespiratory fitness (CRF). CRF of 51 participants was assessed by a maximal exertion test (V̇o2 max). Participants wore a combined accelerometer and HR monitor during a laboratory-based simulation of activities of daily living and for 2 wk in free living. Anthropometrics, HR while lying down, and walking at predefined speeds in laboratory settings were used to estimate CRF. Explained variance (R(2)) was 0.64 for anthropometrics, and increased up to 0.74 for context-specific HR (0.73-0.78 when including fat-free mass). Next, we developed activity recognition and walking speed estimation algorithms to determine the same contexts (i.e., lying down and walking) in free living. Context-specific HR in free living was highly correlated with laboratory measurements (Pearson's r = 0.71-0.75). R(2) for CRF estimation was 0.65 when anthropometrics were used as predictors, and increased up to 0.77 when including free-living context-specific HR (i.e., HR while walking at 5.5 km/h). R(2) varied between 0.73 and 0.80 when including fat-free mass among the predictors. Root mean-square error was reduced from 354.7 to 281.0 ml/min by the inclusion of context-specific HR parameters (21% error reduction). We conclude that pattern recognition techniques can be used to contextualize HR in free living and estimated CRF with accuracy comparable to what can be obtained with laboratory measurements of HR response to walking., (Copyright © 2016 the American Physiological Society.)

Objective: The Social Role Participation Questionnaire (SRPQ) assesses the influence of health on participation in 11 specific and one general participation role across 4 participation dimensions: 'importance', 'satisfaction with time', 'satisfaction with performance' and 'physical difficulty'. This study aimed to translate the SRPQ into Dutch, and assess the clinimetric properties and aspects of its validity among patients with ankylosing spondylitis (AS)., Methods: Translation was performed using the dual panel approach. For each participation dimension, internal consistency, test-retest reliability (n=31), and construct validity were assessed in 246 patients with AS., Results: The translation required only minor adaptations. Cronbach αs were α≥0.7. A strong correlation was present between satisfaction with 'time' and 'performance'(r=0.85). Test-retest reliability was satisfactory (κ=0.79-0.95). Correlations with participation domains of the Short-Form Health Survey 36 (SF-36), the WHO Disease Assessment Score II, and generic as well as disease-specific health outcomes (Physical and Mental component scale of the SF-36, Satisfaction With Life Scale, Bath Ankylosing Spondylitis Disease Index (BASDAI), Bath Ankylosing Spondylitis Functioning Index (BASFI)) were at least moderate (r=-0.41 to 0.75) for all dimensions except for 'role importance' where correlations were weak (r≤40). Discriminative ability across 5 self-reported health states was good for all dimensions (p<0.01). The 'general participation' role showed similar reliability and validity for each dimension, as the average of the all 11 roles., Conclusions: The Dutch version of the SRPQ is available to help understand social role participation of patients with AS. The dimension 'role importance' measures a distinct aspect of participation. The general participation item was a good global measure of participation.

Objective: To compare the total amount of physical activity (TPA) and time spent in various activity intensities of patients with ankylosing spondylitis (AS) and population controls, and to explore factors related to physical activity (PA)., Methods: Subjects were asked to wear a triaxial accelerometer for 7 days and to complete a series of questionnaires. Multivariable regressions were used to assess generic determinants of TPA in patients and controls, and in patients to explore demographic and disease-specific determinants of various PA intensities., Results: One hundred and thirty-five patients [51 ± 13 yrs, 60% men, body mass index (BMI) 26.0 ± 4.3 kg/m(2)] and 99 controls (45 ± 12 yrs, 67% men, BMI 25.1 ± 4.3 kg/m(2)) were included. Patients did not differ from controls regarding TPA (589 vs 608 vector count/min, p = 0.98), minutes/day spent in sedentary (524 vs 541, p = 0.17), and light PA (290 vs 290 p = 0.95), but spent fewer minutes/day in moderate to vigorous PA (MVPA; 23 vs 30 min/day, p = 0.006). Perceived functional ability (physical component summary of the Medical Outcomes Study Short Form-36) and BMI were associated with TPA independent of having AS (p interaction = 0.21 and 0.94, respectively). Additional analyses in patients showed that time spent in MVPA was negatively influenced by BMI, physical function (Bath AS Functional Index), and disease duration. In patients ≥ 52 years old, a higher Bath AS Disease Activity Index was associated with less time spent in sedentary and more time spent in light activities., Conclusion: Compared with controls, patients with AS had similar TPA, but may avoid engagement in higher intensities of PA. Lower levels of functional ability and higher BMI were associated with lower TPA in both patients and controls.

Background: Although strength exercises evidently have both physiological and psychological health benefits across all ages, they are erroneously considered to adversely affect health status in youngsters. The aim of this study was to examine parental attitudes towards their child's physical activity in general, as well as aerobic and strength exercises in particular., Methods: In total, 314 parents from an online panel representative of the Dutch population completed an online survey about their own physical activity and that of their child (12-15 years old). The study also explored reasons for non-participation, and attitudes about the parents' own and their child's physical activity level., Results: Parents consistently reported a positive attitude towards aerobic exercises, but a less positive attitude regarding strength exercises. Parents were more likely to indicate that their child was not allowed to participate in strength exercises (29.6 %) than aerobic exercises (4.0 %). They thought that strength exercises could interfere with optimal physical development., Conclusions: This study consistently shows that parents have a positive attitude towards aerobic exercises, but a less positive attitude regarding strength exercises. We suggest testing interventions to increase parental understanding of the advantages of and possibilities for (e.g., facilities) strength training on their child's health.

Background: South Asians were reported to have a higher liver fat content as compared to BMI-matched Caucasians. This study compared the increase in liver fat content in response to overfeeding with a high fat diet in South Asian and Caucasian men when matched for body fat percentage., Methods: Ten South Asian men (BMI 18-29 kg/m(2)) and 10 Caucasian men (BMI 22-33 kg/m(2)), aged 20-40 y, matched for body fat percentage, were included. A weight maintenance diet was given for 3 days based on the individual energy requirement. Individual energy requirement of the subjects was calculated based on their body composition (measured by hydro densitometry and deuterium dilution) and activity counts (accelerometer). Liver fat content was measured before and after 4 days of overfeeding (50 % excess energy need) with a high fat diet (60 % energy from fat). Fat distribution was measured by anthropometry and an MRI scan of the abdomen while liver fat content using 1H-MRS., Results: While having a similar body fat % (P = 0.58), South Asians had a lower BMI (P = 0.04) than Caucasians. Liver fat content at baseline did not differ between ethnicities (P = 0.48) and was associated with visceral fat area (P = 0.002, R(2) = 0.56) but not with ethnicity (P = 0.13). Overfeeding with a high fat diet significantly increased liver fat (P = 0.01) but the increase did not differ between ethnicities (P = 0.47). There was no difference in the total abdominal fat area (P = 0.37), subcutaneous abdominal fat area (P = 0.18) and visceral fat area (VAT, P = 0.32). However as a percentage of the total abdominal fat area, VAT was higher in South Asians (P = 0.003)., Conclusion: Despite a relatively higher percentage of visceral fat area, liver fat increased similarly in South Asian and Caucasian men in response to overfeeding with a high fat diet., Trial Registration: The study was registered in the public trial registry www.ccmo.nl No. NL31217.068.10.

Background: In developing countries where access to water and food is not guaranteed, women may have to travel long distances or engage in intense physical activities to gather food. This may compromise their water requirements and overall nutritional status. The aim of the study was to determine water turnover, physical activity and body composition among women in Kenya and to describe the differences between rural and urban Kenyan women., Methods: Thirty women from Narok County who were not pregnant at the time of the study were recruited. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared. Deuterium dilution was used to determine total body water (TBW) and water turnover was measured from deuterium elimination. Fat-free mass (FFM) was calculated by assuming a constant hydration fraction of 73.2%. Accelerometers (Actigraph GT3X) were used to assess physical activity and expressed as Vector magnitude counts per day (VM/day). Simple and multiple linear regressions were used to define the determinants of water turnover., Results: Mean BMI was 23.4 ± 4.1 and 21.5 ± 3.8 among rural and urban women respectively. The prevalence of overweight (BMI > 25 kg/m(2)) was 24.1% and of underweight (BMI < 18.4 kg/m2)) was 25%. The mean total body water (TBW) was 29.3 ± 4.2 liters (L) and water turnover was 3.2 ± 0.8 liters per day (L/day). Water loss was positively associated with BMI (R(2) = .45, p < 0.001, n = 28) and Fat mass index (FMI) (R(2) = .41, p < 0.001, n = 28). Water loss was also positively associated with physical activity (PA) (R(2) = .25, p < 0.05, n = 22). Multiple regression analysis showed that physical activity in addition to BMI in the model explained an additional 15% of the variation in water turnover (r(2) = 0.53, p < 0.05; ∆r(2) = 0.15, p < 0.05, n = 22) compared to BMI alone (r(2) = 0.38, p < 0.005 n = 22)., Conclusion: BMI together with physical activity were the strongest predictors of water loss.

Purpose of Review: Optimizing the approach to combat childhood obesity, we emphasize the importance of combining both biological and psychological knowledge. In such an approach, strength exercises might be an important aspect in the treatment and prevention of childhood obesity., Recent Findings: Recent evidence indicates plausible effects of the role of resistance exercise in combating the negative health effects of childhood obesity. When looking at body composition, overweight youngsters do not only have a higher fat mass, but also a higher muscle mass compared with their normal-weight counterparts. With that, they are also stronger and better in exercises wherein the focus is on absolute strength, making them - under the right circumstances - more motivated to engage in resistance exercise and ultimately maintain a physically active lifestyle., Summary: More and more children are obese, and obese children become obese adults. One reason that overweight youngsters are not physically active is that they are outperformed by normal-weight youngsters, and one reason they are overweight is because they are not physically active. To combat childhood obesity, strength exercise might be a solution to break the vicious cycle.

Background: Health is associated with amount of daily physical activity. Recently, the identification of sedentary time as an independent factor, has gained interest. A valid and easy to use activity monitor is needed to objectively investigate the relationship between physical activity, sedentary time and health. We compared validity and reproducibility of physical activity measurement and posture identification of three activity monitors, as well as user friendliness., Methods: Healthy volunteers wore three activity monitors simultaneously: ActivPAL3, ActiGraphGT3X and CAM. Data were acquired under both controlled (n = 5) and free-living conditions (n = 9). The controlled laboratory measurement, that included standardized walking intensity and posture allocation, was performed twice. User friendliness was evaluated with a questionnaire. Posture classification was compared with direct observation (controlled measurement) and with diaries (free living). Accelerometer intensity accuracy was tested by correlations with walking speed. User friendliness was compared between activity monitors., Results: Reproducibility was at least substantial in all monitors. The difference between the two CAM measurements increased with walking intensity. Amount of correct posture classification by ActivPAL3 was 100.0% (kappa 0.98), 33.9% by ActiGraphGT3X (kappa 0.29) and 100.0% by CAM (kappa 0.99). Correlations between accelerometer intensity and walking speed were 0.98 for ActivPAL3, 1.00 for ActiGraphGT3X and 0.98 for CAM. ICCs between activity monitors and diary were 0.98 in ActivPAL3, 0.59 and 0.96 in ActiGraphGT3X and 0.98 in CAM. ActivPAL3 and ActiGraphGT3X had higher user friendliness scores than the CAM., Conclusions: The ActivPAL3 is valid, reproducible and user friendly. The posture classification by the ActiGraphGT3X is not valid, but reflection of walking intensity and user friendliness are good. The CAM is valid; however, reproducibility at higher walking intensity and user friendliness might cause problems. Further validity studies in free living are recommended.

Background: Stunting and overweight are nutritional problems affecting most of sub-Saharan Africa. The region now has the world's highest rate of stunting among children (43%), while overweight and obesity are becoming a global epidemic, and Africa is not spared. The past two decades have seen a dramatic increase in obesity in sub-Saharan Africa., Objective: The purpose of this systematic review is to explore the determinants of stunting and overweight in sub-Saharan Africa., Methods: A literature search was conducted in PubMed using the key words stunting, overweight, obesity, Africa, sub-Saharan Africa, determinants, and prevalence. Limits were set to include articles published between 1990 and 2012. The systematic review resulted in 38 studies, and after selection based on title, content, and country of the study, 18 studies were eligible for this review. Data were analyzed by the chi-square test., Results: The prevalence rates of stunting and overweight were dependent on socioeconomic, demographic, and environmental factors. Many studies indicate that male children and those living in a rural setting are more likely to be stunted, whereas overweight among children depends more on age, household composition, occupation of the mother, and the mother's body mass index. Stunting occurred together with overweight among both boys and girls from 1 to 5 years of age. Stunting was more prevalent among boys than among girls. Indicators of socioeconomic status, such as mother's education, mother's occupation, and household income, were some of the determinants directly linked to stunting, whereas environmental factors, such as rural or urban setting and sanitation, influenced both stunting and overweight. Concurrent stunting and overweight is influenced by maternal and household factors, such as maternal height, age, and education, large household size, and lower socioeconomic status., Conclusions: Although socioeconomic, demographic, and environmental factors were significant in determining stunting and overweight, other factors, such as nutrition and lifestyle, were important risk factors. Stunting in childhood is a risk factor that may result in overweight and obesity later in adolescence and adulthood, indicating the need to screen children below 1 year of age to identify stunting early in life. Promoting exclusive breastfeeding is reported to be important in preventing both stunting and overweight among children. More research is needed to explore the relationship between stunting and overweight and to explore policy guidelines to address the phenomenon.

For the same BMI, South Asians have a higher body fat percentage and an adverse metabolic profile compared with whites. The objective of the present study was to determine the metabolic profiles of South Asian and white men matched for body fat percentage in response to short-term overfeeding with a high-fat diet. A total of ten healthy non-diabetic South Asian men matched for body fat percentage with ten white men were included in the study. A weight-maintenance diet (containing 30 % fat, 55 % carbohydrate and 15 % protein) was provided for 3 d followed by 4 d of overfeeding (150 % of energy requirement) with a high-fat diet (60 % fat, 25 % carbohydrate and 15 % protein). Before and after the overfeeding period, plasma glucose, insulin, TAG, NEFA, total cholesterol and HDL-cholesterol concentrations were determined. Glucose clearance was calculated using a 2 h oral glucose tolerance test. The results revealed that in South Asian and white men, respectively, overfeeding with a high-fat diet decreased plasma TAG concentrations by 0·4 (sd 0·6) and 0·4 (sd 0·5) mmol/l (P diet= 0·008; P ethnicity= 0·24), increased HDL-cholesterol concentrations by 0·12 (sd 0·1) and 0·14 (sd 0·2) mmol/l (P diet= 0·001; P ethnicity= 0·06) and decreased glucose clearance by 48·8 (sd 53·5) and 37·2 (sd 34·2) ml/min per m2 body surface (P diet= 0·004; P ethnicity= 0·18). There was a significant interaction between diet and ethnicity with regard to the changes in total and LDL-cholesterol concentrations (P= 0·01 and 0·007, respectively), which trended towards a larger increase in South Asian subjects than in white subjects. Despite a similar body fat percentage, short-term overfeeding with a high-fat diet had more adverse effects on the lipid profile of South Asians than on that of whites.

Background: Physical functioning can be assessed by different approaches that are characterized by increasing levels of individual appraisal. There is insufficient insight into which approach is the most informative in patients with ankylosing spondylitis (AS) compared with control subjects., Objective: The objective of this study was to compare patients with AS and control subjects regarding 3 approaches of functioning: experienced ability to perform activities (Bath Ankylosing Spondylitis Functional Index [BASFI]), self-reported amount of physical activity (PA) (Baecke questionnaire), and the objectively measured amount of PA (triaxial accelerometer)., Methods: This case-control study included 24 AS patients and 24 control subjects (matched for age, gender, and body mass index). Subjects completed the BASFI and Baecke questionnaire and wore a triaxial accelerometer. Subjects also completed other self-reported measures on disease activity (Bath AS Disease Activity Index), fatigue (Multidimensional Fatigue Inventory), and overall health (EuroQol visual analog scale)., Results: Both groups included 14 men (58%), and the mean age was 48 years. Patients scored significantly worse on the BASFI (3.9 vs 0.2) than their healthy peers, whereas PA assessed by Baecke and the accelerometer did not differ between groups. Correlations between approaches of physical functioning were low to moderate. Bath Ankylosing Spondylitis Functional Index was associated with disease activity (r = 0.49) and physical fatigue (0.73) and Baecke with physical and activity related fatigue (r = 0.54 and r = 0.54), but total PA assessed by accelerometer was not associated with any of these experience-based health outcomes., Conclusions: Different approaches of the concept physical functioning in patients with AS provide different information. Compared with matched control subjects, patients with AS report more difficulties but report and objectively perform the same amount of PA.

The field of application of accelerometry is diverse and ever expanding. Because by definition all physical activities lead to energy expenditure, the doubly labelled water (DLW) method as gold standard to assess total energy expenditure over longer periods of time is the method of choice to validate accelerometers in their ability to assess daily physical activities. The aim of this paper was to provide a systematic overview of all recent (2007-2011) accelerometer validation studies using DLW as the reference. The PubMed Central database was searched using the following keywords: doubly or double labelled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. Limits were set to include articles from 2007 to 2011, as earlier publications were covered in a previous review. In total, 38 articles were identified, of which 25 were selected to contain sufficient new data. Eighteen different accelerometers were validated. There was a large variability in accelerometer output and their validity to assess daily physical activity. Activity type recognition has great potential to improve the assessment of physical activity-related health outcomes. So far, there is little evidence that adding other physiological measures such as heart rate significantly improves the estimation of energy expenditure., (© 2013 The Authors. obesity reviews © 2013 International Association for the Study of Obesity.)

Background: With the same BMI, age, and sex, Asians were reported to have a higher body fat percentage than whites., Objective: This study aimed to determine the difference in body composition and its effect on dietary and 24-h fat oxidation between Asians and whites when they were fed a diet that contained 30% of energy as fat., Design: Seventeen Asians (8 men) were matched with 17 whites (8 men) for BMI, age, and sex. Physical activity was measured for 7 d with an accelerometer. During the last 3 d of the activity measurement, subjects were given a diet to maintain energy balances. Energy expenditure and substrate use were measured for 24 h in a respiration chamber. Dietary fat oxidation was determined from the percentage recovery of deuterium in the urine after a breakfast meal that contained deuterated palmitic acid. Body composition was calculated with a 3-compartment model from body mass, body volume (hydrodensitometry), and total body water (deuterium dilution)., Results: Asians had 5% higher body fat than whites (28.1 ± 7.3% compared with 23.0 ± 6.9%, respectively; P = 0.03). The fat-free mass index tended to be lower in Asians than in whites (16.3 ± 1.6 compared with 17.0 ± 1.7 kg/m(2), respectively; P = 0.07). Dietary fat oxidation as a percentage of fat consumed was 11.7 ± 3.6% compared with 10.8 ± 4.5% (P = 0.50) for Asians and whites, respectively. In Asians and whites, the 24-h fat oxidation as a percentage of total energy expenditure was 17.7 ± 6.9% compared with 19.2 ± 5.1% (P = 0.63), respectively; carbohydrate oxidation was 68.0 ± 6.8% compared with 66.1 ± 5.1% (P = 0.51), respectively; and protein oxidation was 14.3 ± 2.2 compared with 14.7 ± 1.6% (P = 0.61), respectively., Conclusion: Dietary and 24-h fat oxidation were not different between Asians and whites despite differences in body composition. This study was registered in the public trial registry at www.ccmo.nl as NL31217.068.10.

This study investigated which aspects of the individuals' activity behavior determine the physical activity level (PAL). Habitual physical activity of 20 Dutch adults (age: 26-60 years, body mass index: 24.5 ± 2.7 kg/m(2)) was measured using a tri-axial accelerometer. Accelerometer output was used to identify the engagement in different types of daily activities with a classification tree algorithm. Activity behavior was described by the daily duration of sleeping, sedentary behavior (lying, sitting, and standing), walking, running, bicycling, and generic standing activities. Simultaneously, the total energy expenditure (TEE) was measured using doubly labeled water. PAL was calculated as TEE divided by sleeping metabolic rate. PAL was significantly associated (P<0.05) with sedentary time (R=-0.72), and the duration of walking (R=0.49), bicycling (R=0.77), and active standing (R=0.62). A negative association was observed between sedentary time and the duration of active standing (R=-0.87; P<0.001). A multiple-linear regression analysis showed that 75% of the variance in PAL could be predicted by the duration of bicycling (Partial R(2) =59%; P<0.01), walking (Partial R(2) =9%; P<0.05) and being sedentary (Partial R(2) =7%; P<0.05). In conclusion, there is objective evidence that sedentary time and activities related to transportation and commuting, such as walking and bicycling, contribute significantly to the average PAL., (© 2010 John Wiley & Sons A/S.)