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Introduction: The early years are a critical period for establishing healthy 24-hour movement behaviours (physical activity, sedentary behaviour and sleep), yet studies examining prospective associations between all 24-hour movement behaviours and young children's growth and development are lacking. The My Little Moves study aims to (1) examine the prospective association between 24-hour movement behaviours of young children (ie, 0-4 years) and their growth, motor and social-emotional development; and (2) explore potential determinants of young children's 24-hour movement behaviours from an ecological perspective, to inform public health strategies aimed at promoting healthy behaviours and development., Methods and Analysis: My Little Moves is a longitudinal observational cohort study, with data collection at baseline, and after 9 and 18 months follow-up. Data are collected in three subcohorts. In all subcohorts, 24-hour movement behaviours are assessed by parent-report. Additionally in subcohort 1, data on potential determinants are collected by parental questionnaires, including child, parental and environmental factors. In subcohort 2, social-emotional development is assessed using the Dutch version of the Bayley Scales of Infant and Toddler Development-third edition (Bayley-III-NL) Social Emotional Scale. In subcohort 3, data on height and weight, gross motor development, using the Bayley-III-NL Gross Motor Scale, and 7 consecutive days of 24-hour accelerometer data are collected. Hybrid model analyses are used to assess the prospective associations of 24-hour movement behaviours with young children's growth and development. Potential determinants of young children's 24-hour movement behaviours are explored using regression analysis., Ethics and Dissemination: The Medical Ethics Committee of the VU University Medical Center approved the protocol for the My Little Moves study (2022.0020). The results of this study will be disseminated through the network of all authors, to inform public health strategies for promoting healthy 24-hour movement behaviours and contribute to the evidence-base of recommendations for ideal 24-hour movement behaviours in young children., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Understanding health inequalities is essential for improving social justice. Intersectionality refers to a theoretical framework for studying the intersection of multiple social categorizations that create unique experiences and related social inequalities. Currently, the majority of the intersectional studies in the physical activity field have a qualitative design; thus, there is a need for quantitative intersectional studies. This commentary aims to explore primary obstacles impeding intersectional quantitative research and provide recommendations for overcoming these obstacles in physical activity research. In the commentary, we discuss that the lack of accessibility of large-scale and diverse data sets, and suboptimal social categorizations and intersectionality-related questions may contribute to the scarcity of intersectional quantitative research in the field. To facilitate intersectional quantitative analyses, we advocate for making large-scale data sets accessible for intersectional secondary analyses, diverse sampling, standardizing questions and categories related to intersectionality, promoting inclusive research designs and methods, and using the appropriate questions and social categorization that reflect the distinct experiences of each subgroup. By addressing these challenges, researchers may gain new insights into health disparities, making physical activity research more inclusive and contributing to more equitable health outcomes.

Most actions targeting children's health behaviors have limited involvement of children in the development, potentially contributing to disappointing effectiveness. Therefore, in the 3-year "Kids in Action" study, 9- to 12-year-old children from a lower-socioeconomic neighborhood were involved as coresearchers in the development, implementation, and evaluation of actions targeting health behaviors. The current study describes the controlled trial that evaluated the effects on children's energy balance-related behaviors, physical fitness, and self-rated health, as well as experienced challenges and recommendations for future evaluations. Primary school children from the three highest grades of four intervention and four control schools were eligible for participation. Outcome measures assessed at baseline, and at 1- and 2-year follow-up were as follows: motor fitness by the MOPER test ( N = 656, N = 485, N = 608, respectively), physical activity and sedentary behavior by accelerometry ( N = 223, N = 149, N = 164, respectively), and consumption of sugar sweetened beverages and snacks and self-rated health by a questionnaire ( N = 322, N = 281, N = 275, respectively). Mixed-model analyses were performed adjusted for clustering within schools and relevant confounders. Significant beneficial intervention effects were found on self-reported consumption of energy/sports drinks at T2 versus T0, and on total time and ≥5-minute bouts of moderate-to-vigorous physical activity at T1 versus T0. Significant adverse effects were found on "speed and agility" and "coordination and upper-limb speed." No other significant effects were found. The inconsistent intervention effects may be explained by the dynamic cohort and suboptimal outcome measures. We advise future studies with a similar approach to apply alternative evaluation designs, such as the delayed baseline design.

Recently, sedentary behavior recommendations have been included in the public health guidelines of multiple countries, pointing to new opportunities for prevention of chronic disease as well as a potential strategy for initiating long-term behavior change., Objective: To propose an evidence-informed approach to physical activity counseling that starts with a focus on reducing sedentary time., Methods: We put forward a case for addressing changes in sedentary behavior in clinical practice using a narrative review. We also propose a new approach for the assessment and counselling of patients with respect to movement behaviors., Results: There is evidence to support a stepwise approach to physical activity counseling that starts with targeting sedentary behavior, particularly in those who are highly sedentary, or those who have chronic disease, or physical impairments., Conclusions: Our approach encourages clinicians to consider sedentary behavior counseling as a critical first step to physical activity counseling. For many patients, this initial step of reducing sedentary behavior could build a pathway to an active lifestyle., Practical Implications: A shift from long periods of sedentary time to daily routines incorporating more light intensity physical activity could result in meaningful health improvements. Importantly, this approach may be more feasible for highly inactive patients., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Accurate proxy-report questionnaires, adapted to the child's developmental stage, are required to monitor 24-h movement behaviors in young children, especially for large samples and low-resource settings., Objectives: This review aimed to summarize available studies evaluating measurement properties of proxy-report questionnaires assessing physical activity, sedentary behavior and/or sleep in children aged 0-5 years., Methods: Systematic literature searches were carried out in the PubMed, Embase and SPORTDiscus databases, up to January 2021. For physical activity and sedentary behavior questionnaires this is a review update, whereas for sleep questionnaires we included all relevant studies published up to now. Studies had to evaluate at least one of the measurement properties of a proxy-report questionnaire assessing at least duration and/or frequency of physical activity, sedentary behavior and/or sleep in 0- to 5-year-old children. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline was used to evaluate the quality of evidence., Results: Thirty-three studies were included, examining a total of 37 questionnaires. Ten questionnaires were designed for infants, two for toddlers, 11 for preschoolers, and 14 for a broader age range targeting multiple of these age groups. Twenty questionnaires assessed constructs of sleep, four assessed constructs of physical activity, two assessed screen behavior, five assessed constructs of both physical activity and sedentary behavior, and six assessed constructs of all 24-h movement behaviors. Content validity was evaluated for six questionnaires, structural validity for two, internal consistency for three, test-retest reliability for 16, measurement error for one, criterion validity for one, and construct validity for 26 questionnaires. None of the questionnaires were considered sufficiently valid and/or reliable for assessing one or more movement behaviors in 0- to 5-year-old children, and the quality of evidence was mostly low or very low., Conclusions: Valid and/or reliable questionnaires assessing 24-h movement behaviors in 0- to 5-year-olds are lacking. High-quality studies are therefore required, to develop proxy-report questionnaires and evaluate their measurement properties., Prospero Registration Number: CRD42020169268., (© 2022. The Author(s).)

We examined the influence of using different epoch lengths on the classification accuracy of laboratory-controlled sedentary behaviour (SB), and free-living total time and time spent in bouts of SB and moderate-to-vigorous physical activity (MVPA), in children and adolescents. We used two studies including accelerometer-derived data of: 1) controlled activities, i.e. seven sedentary, one standing and one dancing (n = 90); 2) free-living activities (n = 902). For the controlled-activity data, we calculated percentages of time classified as SB and MVPA. For the free-living data, we calculated medians (25th-75th percentiles) of total time and time spent in bouts of SB and MVPA. Applying 8counts/5seconds, 25counts/15seconds and 100counts/60seconds for SB on controlled-activity data revealed respectively (1) 92-96%, 89-99% and 98-100% of sedentary time accurately classified as SB (activity- and age-dependent); (2) 91-98%, 88-99% and 97-100% of standing time classified as SB (age-dependent); (3) 25-37%, 20-25% and 25-38% of dancing time classified as SB (age-dependent). Using longer epochs, children's total time in SB and MVPA decreased while time accumulated in bouts of SB and MVPA accumulated in bouts increased. We conclude that a 60-second epoch seems preferable when the aim is to classify sedentary behaviour, while a shorter epoch length is needed to capture children's short bursts of MPVA. Furthermore, we should be aware that a longer epoch results in averaging of intensities to the middle category., Competing Interests: The authors have declared that no competing interests exist.

Natural killer (NK) cells are a population of innate immune cells known to play a pivotal role against tumor spread. In multiple murine models, it was shown that physical exercise had the potential to increase NK cell antitumor activity through their mobilization and tissue redistribution in an interleukin (IL)-6 and epinephrine-dependent manner. The translation of this finding to patients is unclear. In this randomized pilot trial, we analyzed blood samples of patients with resectable breast or colon cancer who were randomized into an evidence-based moderate-high intensity resistance and aerobic exercise intervention (n = 8) or a control group (n = 6) during the first 9-12 weeks of (neo)adjuvant chemotherapy. In this pilot, we did not solely focus on statistical significance, but also explored whether average between-group differences reached 10%. NK cell degranulation was preserved in the exercise group whereas it decreased in the control group resulting in a between-group difference of 11.4% CD107a + degranulated NK cells (95%CI = 0.57;22.3, p = 0.04) in the presence and 13.8% (95%CI = -2.5;30.0, p = 0.09) in the absence of an anti-epidermal growth factor receptor monoclonal antibody (EGFR-mAb). In line, the between-group difference of tumor cell lysis was 7.4% (95%CI = -9.1;23.9, p = 0.34), and 13.7% (95%CI = -10.1;37.5, p = 0.23) in favor of the exercise group in the presence or absence of EGFR mAb, respectively. Current explorative analyses showed that exercise during (neo)adjuvant chemotherapy may benefit NK cell activity. Future studies with a larger sample size are needed to confirm this finding and to establish its clinical potential. Trial registration: Dutch trial register number NTR4105., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Background: Early childhood is a critical period for growth and development, yet the association with physical activity during this important period is unknown. The aim of this review is to critically summarize the evidence on the prospective associations between physical activity and health and development in children aged < 5 years., Methods: A systematic search in three electronic databases (Pubmed, PsycINFO, and Sportdiscus) was conducted to identify prospective studies examining the associations between physical activity (all types; specified by quantity) and health indicators (body composition, cardiometabolic health, bone health and risks/harm) or development (motor, cognitive and social-emotional development) in young children (mean age < 5 years at baseline). Two independent researchers assessed the methodological quality using the 'Quality Assessment Tool for Quantitative Studies' (EPHPP). This tool covers eight quality criteria: selection bias, study design, confounders, blinding, data collection methods, withdrawals and drop-outs, intervention integrity and data-analysis., Results: Thirty-nine studies, predominantly conducted in preschoolers (ages 3-5 years), were included of which nine were rated as high methodological quality. There was moderate evidence for a positive association between physical activity and motor (n = 11 studies) and cognitive development (n = 10 studies) based on consistent findings from studies having low-to-moderate methodological quality. There was insufficient evidence for an association between physical activity and body composition (n = 15 studies), cardiometabolic health indicators (n = 7 studies), social-emotional development (n = 2 studies) and bone health (n = 2 studies) based on inconsistent findings from studies having weak-to-high methodological quality., Conclusions: There is a need for more high-quality research in order to determine the dose-response relationship between physical activity and health and development in early childhood. Special attention should be paid to studies in children below the age of 3 years.

Background: This pilot trial explores the feasibility of measuring muscle contractile properties in patients with cancer, effects of exercise during chemotherapy on muscle contractile properties and the association between changes in contractile muscle properties and perceived fatigue., Method: Patients who received (neo)adjuvant chemotherapy for breast or colon cancer were randomized to a 9-12 week exercise intervention or a waitlist-control group. At baseline and follow-up, we measured knee extensor strength using maximal voluntary contraction (MVC), contractile muscle properties of the quadriceps muscle using electrical stimulation, and perceived fatigue using the Multidimensional Fatigue Inventory. Feasibility was assessed by the proportion of patients who successfully completed measurements of contractile muscle properties. Exercise effects on muscle contractile properties were explored using linear regression analyses. Between-group differences >10% were considered potentially relevant. Pearson correlation (r p ) of changes in contractile muscle properties and changes in perceived fatigue was calculated., Results: Twenty two of 30 patients completed baseline and follow-up assessments. Measurements of contractile properties were feasible except for muscle fatigability. We found a potentially relevant between-group difference in the rate of force development favoring the intervention group (1192 N/s, 95% CI = -335; 2739). Change in rate of force development was negatively correlated with change in perceived general (r p  = -0.54, P = .04) and physical (r p  = -0.59, P = .02) fatigue., Conclusion: Chemotherapy induces a decrease in the rate of force development, which may reflect a larger loss in type II muscle fibers. This may be attenuated with (resistance) exercise. The increase in the rate of force development was related to a decrease in perceived fatigue., (© 2020 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Children with a low level of neuromotor fitness are less skilled to participate in sports activities. Moreover, lower levels of neuromotor fitness are related to adiposity, lower cardiovascular health, and poor self-esteem in children. The aim of this paper was to determine neuromotor fitness in 10-12-year-old Dutch children over a 10-year period. Test scores measured in 2015/2017 ( N = 533 in 2015, N = 941 in 2017) were compared with scores of same-aged children measured in 2006 ( N = 1986). Neuromotor fitness was assessed using the MOPER fitness test battery, including speed and agility, strength, flexibility, and coordination and upper-limb speed. Data were analyzed using multilevel linear regression models and tobit regression analyses in case of skewed distributions with an excess of zeros. Analyses were stratified by age and gender, and adjusted for level of urbanization. Children in 2015/2017 performed significantly worse on speed and agility (β = 0.8 to 1.1 s), significantly better on coordination/upper-limb speed (β = -1.0 to -0.6 s), and-except for 12-year-old girls-significantly worse on flexibility vs. children in 2006 (β = -3.4 to -1.8 cm). Additionally, upper-body strength was significantly worse among 10-year olds (β = -3.2 to -2.5 s) while leg strength was significantly worse among 11-year-olds in 2015/2017 vs. 2006 (β = -1.8 to -1.7 cm). Trunk strength was worse among 11- and 12-year old boys (β = 1.1 to 1.2 s). In line with a previously observed downward trend in neuromotor fitness among children (1980-2006), we found worse scores on speed and agility, and flexibility in 2015/2017 vs. 2006, stressing the need for interventions aimed at improving neuromotor fitness in order to promote physical activity and future health., (Copyright © 2020 Anselma, Collard, van Berkum, Twisk, Chinapaw and Altenburg.)

This systematic review aims to summarize the evidence regarding the effectiveness of interventions targeting energy balance-related behaviors in children from lower socioeconomic environments and the applied behavior change techniques. The literature search was conducted in Cochrane, Embase, Psycinfo and Pubmed. Articles had to be published between January 2000 and September 2019. Studies were included that i) targeted dietary behavior, physical activity and/or sedentary behavior; ii) had a controlled trial design; iii) included children aged 9-12 years old; iv) focused on lower socioeconomic environments; and v) took place in upper-middle or high income countries. Two independent researchers extracted data, identified behavior change techniques using the Behavior Change Technique Taxonomy v1, and performed a methodological quality assessment using the quality assessment tool of the Effective Public Health Practice Project. We included 24 studies, of which one received a high and three a moderate quality rating. Demonstration, practice and providing instructions on how to perform a behavior were the most commonly applied behavior change techniques. Seven studies reported significant beneficial intervention effects: five on physical activity, one on physical activity and sedentary behavior and one on dietary behavior. When comparing effective versus non-effective interventions, and comparing our review to previous reviews focusing on children from the general population, similar behavior change techniques were applied. More high quality research is needed to evaluate the effectiveness of interventions and their behavior change techniques targeting children of low socioeconomic environments. PROSPERO registration number: CRD42016052599., Competing Interests: The authors have declared that no competing interests exist.

Purpose: The level of daily physical activity in patients with cancer is frequently assessed by questionnaires, such as the Physical Activity Scale for the Elderly (PASE). Objective assessments, with for example accelerometers, may be a good alternative. The aim of this study was to investigate the agreement between the PASE questionnaire and accelerometer-assessed physical activity in a large group of patients with different types of cancer., Methods: Baseline accelerometer and PASE questionnaire data of 403 participants from the REACT (Resistance and Endurance Exercise After Chemotherapy, n = 227), the EXIST (Exercise Intervention After Stem-Cell Transplantation, n = 74), and NET-QUBIC (NEtherlands QUality of Life And Biomedical Cohort Studies In Cancer, n = 102) studies were available for the current analyses. Physical activity was assessed by the PASE questionnaire (total score) and accelerometers (total minutes per day > 100 counts). Linear mixed models regression analysis was used to assess the agreement between the PASE questionnaire and accelerometer-assessed physical activity., Results: The mean (SD) PASE score was 95.9 (75.1) points and mean (SD) time in physical activity measured with the accelerometer was 256.6 (78.8) min per day. The agreement between the PASE score and the accelerometer data was significant, but poor (standardized regression coefficient (B) = 0.36, 95%CI = 0.27; 0.44, p < 0.01)., Conclusion: Agreement between the PASE questionnaire and accelerometer-assessed physical activity was poor. The poor agreement indicates that they measure different physical activity constructs and cannot be used interchangeably to assess the level of daily physical activity in patients with cancer.

Background: All 24-h movement behaviors, i.e. physical activity, sedentary behavior and sleep, are important for optimal health in children. Currently, no tools exist that include all 24-h behaviors and have been proven to be both reliable and valid. Potential reasons for the inadequate validity and reliability of existing questionnaires are the lack of focus on the content validity and lack of involvement of children in the development. Therefore, the aim of this study was to co-create a 24-h movement behavior tool together with 9-12-year-old children., Methods: Concept mapping and photovoice meetings were held to identify children's physical activity behaviors. During concept mapping meetings with four groups of children (n = 40), children generated an extensive list of physical activities they engaged in, sorted the activities in categories and rated the frequency and perceived intensity of these activities. Using photovoice, three groups of children (n = 24) photographed their physical activities during one weekday and one weekend day, named the photographs, and placed them on a timeline. Furthermore, researchers obtained information on relevant items regarding sleep and sedentary behavior by screening existing questionnaires. Thereafter, we developed the first version of MyDailyMoves. Subsequently, we examined the content validity of the tool together with three groups of children (n = 22) and one group of researchers (n = 7) using focus group meetings., Results: MyDailyMoves has a timeline format, onto which children add the activities they performed the previous day. Based on the concept mapping and photovoice studies, eight physical activity categories were included: playing inside, playing outside, sports, hobbies, chores, personal care, transport, and others. Sleep questions and two more sedentary categories (schoolwork and screen time) were added to MyDailyMoves to define and complete the timeline. The content validity study showed that all items in the tool were relevant. However, children mentioned that the activity category 'eating' was missing and the understandability of how to use the tool should be improved by adding an explanatory video. Both suggestions were adopted in the second version., Conclusion: Including the children's perceptions throughout the tool development process resulted in a comprehensive and practical tool which is easy for children to use.

Introduction: Objective measurements of levels of physical activity and fitness in patients with head and neck cancer (HNC) are lacking. Furthermore, demographic, clinical and lifestyle-related correlates of low levels of physical activity and fitness in patients with HNC are unknown. This study aims to investigate the levels of accelerometer that assessed physical activity and fitness in patients with HNC and to identify their demographical, clinical and lifestyle-related correlates. Methods: Two hundred and fifty-four patients who were recently diagnosed with HNC and participated in the NETherlands QUality of life and Biomedical cohort studies In head and neck Cancer (NET-QUBIC) study were included. Physical activity (accelerometer), cardiorespiratory fitness (Chester Step Test), hand grip strength (hand dynamometer) and lower body muscle function (30-second chair-stand test) were assessed. Multivariable linear regression analyses with a stepwise forward selection procedure were used. Results: Patients spent 229 min/d in physical activity of which 18 min/d in moderate-to-vigorous physical activity. The mean predicted VO 2 max was 27.9 ml/kg/min, the mean hand grip strength was 38.1 kg and the mean number of standings was 14.3. Patients with lower educational level, more comorbidity and higher tumor stage spent significantly less time in physical activity. Older patients, females and patients with a higher tumor stage had significantly lower cardiorespiratory fitness levels. Older patients, females, patients with more comorbidity, patients with normal weight and patients who have never smoked had significantly lower hand grip strength. Older patients, patients with lower educational level, smokers and patients with more comorbidity had a significantly lower function of lower body muscle. Conclusions: Pre-treatment levels of physical activity, cardiorespiratory fitness and lower body muscle function are low in patients with HNC. Based on this study, exercise programs targeted and tailored to patients with low levels of physical activity and fitness can be developed.

Objectives: We aimed to investigate accelerometer output corresponding to physical activity intensity cut-points based on percentage of peak oxygen consumption (%VO 2 peak) and Metabolic Equivalent of Task (MET) value in women treated for breast cancer., Design: Laboratory study., Methods: Fifty female patients shortly after completion of treatment for breast cancer were included. VO 2 peak was determined during a cardiopulmonary exercise test. Subsequently, patients performed ten activities with different intensities while wearing an accelerometer on the right hip and a mobile oxycon to assess oxygen consumption. We studied the relationship between energy expenditure (expressed as %VO 2 peak and MET-value) and accelerometer output (in counts per minute (cpm)) with linear regression analyses. We determined accelerometer output corresponding to physical activity intensity cut-points (40% and 60%VO 2 peak; 3 and 6 MET) using regression equations., Results: VO 2 peak was 22.4mL/kg/min (SD 5.2) and resting metabolic rate was 3.1mL/kg/min (SD 0.6). Accelerometer output corresponding to the cut-points for moderate (40% VO 2 peak) and vigorous intensity (60% VO 2 peak) were 1123 and 1911, respectively. The analyses based on MET-values resulted in accelerometer output of 1189cpm for the moderate (3 MET) and 2768 cpm for the vigorous intensity cut-point (6 MET)., Conclusions: Accelerometer outputs for moderate and vigorous intensity physical activity were lower than commonly used cut-points (i.e. 1952 and 5724 cpm), irrespective of the method used to express energy expenditure (%VO 2 peak versus MET-value). Thus, categorizing physical activity intensities based on general-population cut-points, may underestimate physical activity intensities for women treated for breast cancer., (Copyright © 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The present study examined the efficacy of accelerometers for the assessment of free play physical activity (PA) in pre-school-aged children with consideration of epoch length and wear location. Following ethics approval, parental informed consent, and child assent, 66 pre-schoolers aged 3-4 years (30 females and 36 males) wore an accelerometer (ActiGraph GT3X; sampling at 100 Hz) on their non-dominant wrist and their right hip during 1 hour of free play. Concurrently, direct observation, using the OSRAC-P, was used to determine sedentary behavior (SB), light (LPA), or moderate-to-vigorous (MVPA) intensity PA. For the ActiGraph, vertical axis counts and summed vector magnitude (VM) for hip, and VM for wrist, were downloaded using 5-, 10-, 15-, and 30-second epoch lengths. Accelerometer counts were averaged over each 30 seconds to match the observation periods. Receiver operating curve analysis was used to evaluate the ability of the ActiGraph to predict SB, LPA, and MVPA. SB and MVPA obtained from wrist- and hip-worn accelerometers demonstrated fair agreement with direct observation (AUC => 0.7). LPA determined by accelerometer had poor agreement with observed LPA, for both the hip and wrist placement (AUC = 0.53-0.56), with weak levels of specificity (0.34-0.43), although sensitivity was fair (0.74-0.84). This study is the first to examine accelerometer validity, considering wear location and epoch in pre-schoolers during free play, and suggests that the ActiGraph is a fair measure for SB and MVPA in pre-school children. Neither placement performed predominantly better irrespective of epochs or used count data (vertical axis, VM)., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Physical activity has beneficial effects on the health of cancer survivors. We aimed to investigate accelerometer-assessed physical activity and sedentary time in cancer survivors, and describe activity profiles. Additionally, we identify demographic and clinical correlates of physical activity, sedentary time and activity profiles., Methods: Accelerometer, questionnaire and clinical data from eight studies conducted in four countries (n = 1447) were pooled. We calculated sedentary time and time spent in physical activity at various intensities using Freedson cut-points. We used latent profile analysis to identify activity profiles, and multilevel linear regression analyses to identify demographic and clinical variables associated with accelerometer-assessed moderate to vigorous physical activity (MVPA), sedentary time, the highly active and highly sedentary profile, adjusting for confounders identified using a directed acyclic graph., Results: Participants spent on average 26 min (3%) in MVPA and 568 min (66%) sedentary per day. We identified six activity profiles. Older participants, smokers and participants with obesity had significantly lower MVPA and higher sedentary time. Furthermore, men had significantly higher MVPA and sedentary time than women and participants who reported less fatigue had higher MVPA time. The highly active profile included survivors with high education level and normal body mass index. Haematological cancer survivors were less likely to have a highly active profile compared to breast cancer survivors. The highly sedentary profile included older participants, males, participants who were not married, obese, smokers, and those < 12 months after diagnosis., Conclusions: Cancer survivors engage in few minutes of MVPA and spend a large proportion of their day sedentary. Correlates of MVPA, sedentary time and activity profiles can be used to identify cancer survivors at risk for a sedentary and inactive lifestyle.

Purpose: To date, epidemiological studies have focused on the potential health effects of total volume of physical activity (PA) or sedentary behavior (SB). However, two persons may have the same volume of PA or SB but accumulated in a completely different sequence. The pattern of accumulating PA and SB might be more important for health effects than the total volume. Therefore, the aim was to develop a sophisticated algorithm translating accelerometer data into detailed sequence maps considering how PA and SB are accumulated throughout the day., Methods: We developed a novel algorithm to convert accelerometer counts into a sequence map based on behavior states defined by a combination of intensity (SB, light, moderate, and vigorous intensity) and duration (sporadic accumulation or in bouts of different duration). In addition, hierarchical cluster analysis was applied to identify clusters of children with similar behavioral sequence maps., Results: Clustering resulted in seven clusters of children with similar PA and SB sequence maps: an average cluster (33% of children); a cluster with relatively more SB, light, and moderate PA in bouts (SB and PA bouters, 31%); a cluster characterized by more sporadic SB and light PA (light activity breakers, 26%); and four smaller clusters with 7% of the children or less., Conclusion: This novel algorithm is a next step in more sophisticated analyses of accelerometer data considering how PA and SB are accumulated throughout the day. The next step is identifying whether specific patterns of accumulating PA and SB are associated with improved health outcomes.

Background and Objective: This review is an update of a previous review published in 2010, and aims to summarize the available studies on the measurement properties of physical activity questionnaires for young people under the age of 18 years., Methods: Systematic literature searches were carried out using the online PubMed, EMBASE, and SPORTDiscus databases up to 2018. Articles had to evaluate at least one of the measurement properties of a questionnaire measuring at least the duration or frequency of children's physical activity, and be published in the English language. The standardized COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist was used for the quality assessment of the studies., Results: This review yielded 87 articles on 89 different questionnaires. Within the 87 articles, 162 studies were conducted: 103 studies assessed construct validity, 50 assessed test-retest reliability, and nine assessed measurement error. Of these studies, 38% were of poor methodological quality and 49% of fair methodological quality. A questionnaire with acceptable validity was found only for adolescents, i.e., the Greek version of the 3-Day Physical Activity Record. Questionnaires with acceptable test-retest reliability were found in all age categories, i.e., preschoolers, children, and adolescents., Conclusion: Unfortunately, no questionnaires were identified with conclusive evidence for both acceptable validity and reliability, partly due to the low methodological quality of the studies. This evidence is urgently needed, as current research and practice are using physical activity questionnaires of unknown validity and reliability. Therefore, recommendations for high-quality studies on measurement properties of physical activity questionnaires were formulated in the discussion., Prospero Registration Number: CRD42016038695.

Background: In today's society, few adolescents meet physical activity guidelines and effects of physical activity promoting programmes are disappointing. In studies exploring determinants of physical activity, the perspective of adolescents themselves is largely lacking. Also, there is a lack of knowledge on potential environmental determinants of adolescent physical activity. Therefore, this study aimed to explore adolescents' perspectives on characteristics of an activity-friendly environment., Methods: Concept mapping meetings were conducted with four secondary school classes, including 115 adolescents (13-17 years). Each student generated ideas regarding the characteristics of an activity-friendly environment. For each school class, ideas were combined and identical ideas were removed. Next, students individually sorted all ideas, based on self-perceived similarity, and rated their importance on a five-point Likert-scale. A concept map was created for each school class using multidimensional scaling and hierarchical cluster analysis. Finally, the researchers named the potential environmental determinants within the clusters., Results: The concept maps depicted 23 unique potential determinants of activity friendliness, of which 15 were similar across all school classes. Potential determinants were categorized in the physical-, social-, economic-, and motivational domain. The most frequent and important adolescent-perceived determinants of activity friendliness across all school classes belonged to the physical domain, e.g. a suitable area including a proper surface for a variety of sports, and good lighting in the playground., Conclusions: Our findings show that adolescents perceive potential determinants in the physical and economic domain as most important for activity friendliness, indicating that future interventions might benefit from targeting potential determinants within these domains.

The primary aim was to examine child- and parent-related correlates of accelerometer-assessed overall total and prolonged (i.e., accumulated in bouts of ≥10 consecutive minutes) sedentary time (SED) in 5- to 6-year-old children. Second, child- and parent-related correlates of total and prolonged SED during weekend days and the after school period were examined, as associations with parent-related correlates may be stronger during these periods. SED and moderate-to-vigorous-intensity physical activity (MVPA) were assessed by ActiGraph accelerometers in children ( n = 836) and one of their parents/carers. Parents completed a questionnaire examining potential parent-related correlates. Multilevel models examined associations between potential correlates and children's total and prolonged SED. Children's MVPA was the only correlate that was consistently negatively associated with both total and prolonged SED across the different time periods (overall, after school, and weekend days). Higher total SED in parents was associated with higher overall total SED and weekend total SED in children. Higher body mass index z -scores of children were associated with lower overall total and prolonged SED. Girls had lower prolonged SED after school than boys. Older children had lower total SED during the weekend. In conclusion, few potential correlates were associated with young children's total or prolonged SED and most associations differed by time period.

Background: As physical inactivity is particularly prevalent amongst lower-educated adolescent girls, interventions are needed. Using a co-creational approach increases their engagement and might be effective. This study aimed to: (1) describe the co-creation process, (2) evaluate how girls experienced co-creation, and (3) evaluate the effect of the co-creational interventions on physical activity, individual, sociocultural and school-based factors. Methods: Three intervention schools (n = 91) and three control schools (n = 105) across Flanders participated. A questionnaire was completed pre (September-October 2014) and post (April-May 2015). In between, sessions with a co-creation group were organised to develop and implement the intervention in each intervention school. Focus groups were conducted to evaluate the co-creational process. Results: School 1 organised sport sessions for girls, school 2 organised a fitness activity and set up a Facebook page, school 3 organised a lunch walk. Girls were positive about having a voice in developing an intervention. No significant effects were found, except for small effects on extracurricular sports participation and self-efficacy. Conclusions: Using a co-creational approach amongst adolescent girls might be a feasible approach. However, as interventions were minimal, effects were limited or undetectable. Future co-creation projects could consider the most optimal co-creation process, evaluation design and intensively test this approach., Competing Interests: The authors declare no conflict of interest.

Background: This study examined the frequency of and differences in sedentary bouts of different durations and the total time spent in sedentary bouts on a weekday, a weekend day, during school hours, during after-school hours and in the evening period in a sample of 10- to 12-year-old Belgian children., Methods: Accelerometer data were collected as part of the ENERGY-project in Belgium (n = 577, 10.9 ± 0.7 years, 53% girls) in 2011. Differences in total sedentary time, sedentary bouts of 2-5, 5-10, 10-20, 20-30 and ≥30 min and total time accumulated in those bouts were examined on a weekday, a weekend day, during school hours, during after-school hours and in the evening period, using multilevel analyses in MLwiN 2.22., Results: More than 60% of the participants' waking time was spent sedentary. Children typically engaged in short sedentary bouts of 2-5 and 5-10 min, which contributed almost 50% towards their total daily sedentary time. Although the differences were very small, children engaged in significantly fewer sedentary bouts of nearly all durations during after-school hours compared to during school hours and in the evening period. Children also engaged in significantly fewer sedentary bouts of 5-10, 10-20, and 20-30 min per hour on a weekend day than on a weekday., Conclusions: Although primary school children spend more than 60% of their waking time sedentary, they generally engaged in short sedentary bouts. Children's sedentary bouts were slightly longer on weekdays, particularly during school hours and in the evening period, although the differences were very small. These results suggest that in this age group, interventions focusing on reducing total sedentary time rather than interrupting prolonged sedentary time are needed.

Background: The prominence of sedentary behavior research in health science has grown rapidly. With this growth there is increasing urgency for clear, common and accepted terminology and definitions. Such standardization is difficult to achieve, especially across multi-disciplinary researchers, practitioners, and industries. The Sedentary Behavior Research Network (SBRN) undertook a Terminology Consensus Project to address this need., Method: First, a literature review was completed to identify key terms in sedentary behavior research. These key terms were then reviewed and modified by a Steering Committee formed by SBRN. Next, SBRN members were invited to contribute to this project and interested participants reviewed and provided feedback on the proposed list of terms and draft definitions through an online survey. Finally, a conceptual model and consensus definitions (including caveats and examples for all age groups and functional abilities) were finalized based on the feedback received from the 87 SBRN member participants who responded to the original invitation and survey., Results: Consensus definitions for the terms physical inactivity, stationary behavior, sedentary behavior, standing, screen time, non-screen-based sedentary time, sitting, reclining, lying, sedentary behavior pattern, as well as how the terms bouts, breaks, and interruptions should be used in this context are provided., Conclusion: It is hoped that the definitions resulting from this comprehensive, transparent, and broad-based participatory process will result in standardized terminology that is widely supported and adopted, thereby advancing future research, interventions, policies, and practices related to sedentary behaviors.

Background: Both parents' and children's perception of children's weight status may be important predictors of slimming and energy-balance related behaviours, independent of children's actual weight status., Objectives: We examined the cross-sectional association of children's self-reported slimming and energy-balance related behaviours with children's (i) actual, (ii) self-perceived and (iii) parent-perceived weight status., Methods: Data of 10- to 12-year-old European children and their parents were used. Multilevel logistic and linear regression analyses were performed, adjusting for age, gender, parental weight controlling behaviours, education, marital status and ethnicity., Results: Independent of their actual weight status, a higher proportion of children reported slimming when they or their parents perceived them as too fat. Children's self-perceived weight status was more strongly associated with slimming than their parents' perception or their actual weight status. Moreover, children who perceive themselves as overweight reported less physical activity and more screen time. Children whose parents perceive them as overweight reported less physical activity., Conclusions: Children's own perception of their weight status appears to be more important for their self-reported slimming than their actual or their parent's perceptions of their weight status. Additionally, children's self-perceived weight status seems important in engaging more physical activity and reduces screen time., (© 2016 World Obesity Federation.)

Objectives: Evidence suggests that physical activity is positively related to several aspects of cognitive functioning in children, among which is selective attention. To date, no information is available on the optimal frequency of physical activity on cognitive functioning in children. The current study examined the acute effects of one and two bouts of moderate-intensity physical activity on children's selective attention., Design: Randomized controlled trial (ISRCTN97975679)., Methods: Thirty boys and twenty-six girls, aged 10-13 years, were randomly assigned to three conditions: (A) sitting all morning working on simulated school tasks; (B) one 20-min physical activity bout after 90min; and (C) two 20-min physical activity bouts, i.e. at the start and after 90min. Selective attention was assessed at five time points during the morning (i.e. at baseline and after 20, 110, 130 and 220min), using the 'Sky Search' subtest of the 'Test of Selective Attention in Children'. We used GEE analysis to examine differences in Sky Search scores between the three experimental conditions, adjusting for school, baseline scores, self-reported screen time and time spent in sports., Results: Children who performed two 20-min bouts of moderate-intensity physical activity had significantly better Sky Search scores compared to children who performed one physical activity bout or remained seated the whole morning (B=-0.26; 95% CI=[-0.52; -0.00])., Conclusions: Our findings support the importance of repeated physical activity during the school day for beneficial effects on selective attention in children., (Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

An increasing number of interventions targeting sedentary behaviour in children have emerged in recent years. Recently published reviews included sedentary behaviour and physical activity interventions. This review critically summarizes evidence on the effectiveness of intervention strategies that exclusively targeted reducing sedentary time in children and adolescents. We performed a systematic literature search in Pubmed, Embase and the Cochrane Library through November 2015. Two independent reviewers selected eligible studies, extracted relevant data and rated the methodological quality using the assessment tool for quantitative studies. We included 21 intervention studies, of which 8 studies scored moderate on methodological quality and 13 studies scored weak. Four out of eight moderate quality studies reported significant beneficial intervention effects.Although descriptions of intervention strategies were not always clearly reported, we identified encouragement of a TV turnoff week and implementing standing desks in classrooms as promising strategies. Due to a lack of high quality studies and inconsistent findings, we found no convincing evidence for the effectiveness of existing interventions targeting solely sedentary behaviour. We recommend that future studies apply mediation analyses to explore which strategies are most effective. Furthermore, to increase the effectiveness of interventions, knowledge of children's motives to engage in sedentary behavior is required, as well as their opinion on potentially effective intervention strategies.

Increasing attention is paid to the potential health effects of children's sedentary bouts and breaks, rather than total sedentary time. This paper discusses currently used operational definitions of sedentary bouts and breaks in studies among children. Remarkably, these studies applied different operational definitions, complicating comparison between studies. To advance the field of sedentary behaviour epidemiology, we need a clear and 'evidence-based' operationalization for such sedentary bouts and breaks., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Evidence on the association between different screen behaviours and cardiometabolic biomarkers in children is limited. We examined the independent relationship of TV time and PC time with cardiometabolic biomarkers in Dutch 5-6 year old children., Methods: Cross-sectional analyses were conducted December 2012-March 2013 using data from a multi-ethnic cohort (the ABCD study, n = 1,961). TV and PC time and physical activity were assessed by parent-report. Body weight, height, waist circumference and blood pressure were measured using a standard protocol. Fasting capillary blood samples were collected. A cardiometabolic function score was computed as the mean of the inverted standardised values of waist circumference, mean of systolic and diastolic blood pressure, glucose, HDLC (not inverted), and triglycerides., Results: Mean TV time was 1.2 (± 0.8) hr/day and mean PC time was 0.2 (± 0.4) hr/day. After adjustment for birth weight, height, maternal education, PC time, and physical activity, excessive TV time (>2 hrs/day) was adversely associated with waist circumference (b = 0.39, 95% CI: 0.004;0.78) while PC time was beneficially associated with HDLC levels (b = 0.04, 95% CI: 0.001;0.08). We found no additional significant associations of TV time, or PC time with any of the cardiometabolic biomarkers., Conclusions: We found no convincing evidence for an association between TV or PC time and cardiometabolic function in apparently healthy 5-6 yr olds.

Although detrimental associations of sitting time and health indicators have been observed in young adults, evidence of pathophysiological mechanisms is lacking. Therefore, this study tested the hypothesis that the acute cardiometabolic effects of prolonged sitting can be compensated by hourly interruptions to sitting in healthy, young adults. Additionally, leg muscle activation during sitting and moderate-intensity physical activity interruptions was assessed. Eleven apparently healthy adults (18-24 yr; five men/six women) participated in this randomized, crossover study, involving two experimental conditions: 1) 8 h prolonged sitting and 2) 8 h of sitting, interrupted with hourly, 8-min, moderate-intensity cycling exercise bouts. In both conditions, participants consumed two standardized, high-fat mixed meals after 1 and 5 h. Capillary blood samples were collected hourly during each 8-h experimental condition. Muscle activity was measured using electromyography. Muscle activity during cycling was seven to eight times higher compared with rest. Postprandial levels of C-peptide were significantly lower (unstandardized regression coefficient = -0.19; confidence interval = [-0.35; -0.03]; P = 0.017) during interrupted sitting compared with prolonged sitting. Postprandial levels of other cardiometabolic biomarkers (e.g., glucose, triglycerides, cholesterol) were not significantly different between conditions. Hourly physical activity interruptions in sitting time, requiring a muscle activity of seven to eight times the resting value, led to an attenuation of postprandial C-peptide levels but not for other cardiometabolic biomarkers compared with prolonged sitting in healthy, young adults. Whether this acute effect transfers to chronic effects over time is unknown.

In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which corresponded to 38% of the maximal dynamic muscle force. Biopsies of the vastus lateralis muscle were taken from six subjects at rest and during the exercise, two at each time point. From the first biopsy single fibers were isolated and characterized as type I and II, and phosphocreatine-to-creatine (PCr/Cr) ratios and periodic acid-Schiff (PAS) stain intensities were measured. Cross sections were cut from the second biopsy, individual fibers were characterized as type I and II, and PAS stain intensities were measured. A decline in PCr/Cr ratio and in PAS stain intensity was used as indication of fiber recruitment. Within 1 min of exercise both type I and, although to a lesser extent, type II fibers were recruited. Furthermore, the PCr/Cr ratio revealed that the same proportion of fibers was recruited during the whole 45 min of exercise, indicating a rather constant recruitment. The PAS staining, however, proved inadequate to fully demonstrate fiber recruitment even after 45 min of exercise. We conclude that during cycling exercise a greater proportion of type II fibers is recruited than previously reported for isometric contractions, probably because of the dynamic character of the exercise. Furthermore, the PCr/Cr ratio method is more sensitive in determining fiber activation than the PAS stain intensity method.