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International audience; Physical inactivity, i.e., not reaching the recommended level of physical activity (PA) and sedentary behaviors (SB), i.e., sitting time have been associated with increased risk for common metabolic diseases. Recent epidemiological data suggest that high volumes of SB are detrimental for metabolic health, even in the presence of regular exercise, i.e., moderate/vigorous (MVPA). This suggests that the health effects of SB are independent from those of exercise. However, experimentally testing this hypothesis is complicated because of the difficulty in disassociating SB from PA. Bedrest studies, a traditional space science model, can offer new insights. In some bedrest studies, an exercise training protocol has been used to counteract the harmful effects of inactivity. While bedrest induces an inactive and sedentary state, exercise with bedrest represents a unique model of sedentary yet physically active people. Here, we review bedrest studies with and without exercise training. Although exercise training prevents the loss of muscle mass and function, even large volumes of exercise are not sufficient to fully counteract the negative metabolic adaptations triggered by inactivity. This observation supports the existence of independent adverse health effects of SB, but also the potential benefits of non‐exercise activity, i.e., daily living light‐intensity activities (LPA). We gathered available data to examine the complex relationships between exercise, non‐exercise activity, SB and health outcomes. Given the large amount of SB in modern societies, the sole promotion of exercise, i.e., MVPA may be insufficient, and promotion of LPA may be a complimentary approach to improve health.

Introduction:\ud \ud Regular moderate‐to‐vigorous physical activity (MVPA) is associated with improved mental health, but the evidence for the effect of reducing sedentary behaviour (SB) or increasing light PA (LPA) in older adults, is lacking. Using isotemporal substitution (IS) models, the aim of this paper is to investigate the effect of substituting SB with LPA or MVPA on associations with mental health in older adults.\ud \ud Methods:\ud \ud Data from 1,360 older adults (mean age 75.18 years) in four countries were utilised. PA and SB was measured using ActiGraph wGT3X‐BT+ accelerometers worn for 7 days. Self‐rated mental health was measured using the Hospital and Anxiety Depression Scale (HADS). IS models estimated cross‐sectional associations when 30 minutes of one behaviour was substituted with another. Models were adjusted for age, sex, marital status, educational attainment.\ud \ud Results:\ud \ud Substituting 30 minutes of SB with LPA (β ‐0.37; 95%CI ‐0.42, ‐0.32) or MVPA (β ‐0.14; 95%CI ‐0.21, ‐0.07) and substituting LPA with MVPA (β ‐0.11; 95%CI ‐0.18, ‐0.04) was associated with improvements in anxiety. However, substituting 30 minutes of SB with LPA (β 0.55; 95%CI 0.49, 0.62) was associated with increased depression.\ud \ud Conclusion:\ud \ud Replacing 30 minutes of SB with LPA or MVPA was associated with improved anxiety symptoms in older adults. Greater benefits were observed when shifting SB and LPA to MVPA.

Background: Prolonged sedentary time is associated with adverse health outcomes, after controlling for the role of moderate-to-vigorous physical activity. We previously reported on a four-week randomized trial using a sit-stand desk (SSD) intervention that decreased sedentary time at work without changing activity level during non-work hours. Purpose: The purpose of this study was to measure the impact of the SSD on sitting time and activity level one year after the original intervention. Methods: A pre-post design was used where the control period from the original study was regarded as “pre” and the measurements made in the follow-up study as “post.” The follow-up study was conducted in the same office workers over a two-week period in June 2013. Results: Fifteen out of the 23 participants took part in the follow-up study. Self-reported sitting time during work-hours was decreased by 22% (95% CI: 15% to 29%; p

Sedentary time is associated with increased obesity in police officers. Caffeine intake may reduce sedentary time but it has not been extensively investigated. In the present study, the effect of caffeine ingestion on sedentary time was investigated in obese police officers. Fourteen obese police officers ingested either 5 mg/kg of caffeine or cellulose (placebo) for six days. Information on inactivity time, time spent with physical activities, self-reported perception of tiredness, and physical activity disposition was obtained daily during the intervention period. Sedentary and physical activity times were divided into two intraday periods (T1: 08:00 am-02:00 pm and T2: 02:00 pm-08:00 pm). Caffeine intake decreased the sedentary time in both T1 (79.2±2.2%) and T2 (79.1±2.5%), when compared with T2 of the placebo condition (81.1±3.6%, P0.05), but it increased the self-reported physical activity disposition compared to the placebo condition (4.5±2.7 vs 3.2±2.3 units, P

Research has found that social relationships are central to the health and well-being of an aging population. Evidence exploring the association between physical activity (PA) and sedentary behavior (SB) with social isolation and loneliness is limited. This study uses objectively measured PA and SB (ActiGraph®) and self-reported measures of loneliness (the De Jong Gierveld Loneliness Scale) and social engagement (the Lubben Social Network Scale) from the SITLESS study, a European-wide study of community-dwelling older adults. Social isolation was associated with SB where higher levels of SB were associated with an increase in the level of social isolation, controlling for age, sex, living arrangements, employment status, body mass index, educational background, marital status, and self-reported general health. In contrast, PA was not associated with social isolation, and neither SB nor PA was a statistically significant predictor of loneliness. SB may be linked to social isolation in older adults, but PA and SB are not necessarily linked to loneliness in older community-dwelling adults.

Background: In response to the COVID-19 pandemic, physical distancing measures have been implemented globally. Canadians have been instructed to stay at home, which has likely resulted in significant changes in their physical activity. Using data from a national physical activity tracking app (PAC app), we aimed to determine device-measured physical activity levels immediately prior to and following the implementation of physical distancing measures in Canada to provide evidence for the development of physical activity recommendations for future pandemics or second wave infections.Methods: Demographic and physical activity data were extracted from the ParticipACTION app (PAC app), using a 10-week (10 February to 19 April 2020) quasi-experimental design to determine changes in physical activity 4 weeks pre-pandemic and 6 weeks post-pandemic declaration. Weekly physical activity levels were monitored through wearable fitness trackers and health apps linked to the PAC app, to record moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), and steps. Repeated measure ANOVA was used to determine changes over time (mean ± SE).Findings: A total of 2,338 Canadians who were mostly 35–44 years old (26.6%) and female (90.2%) were included in the analysis. MVPA, LPA, and steps significantly declined immediately following the declaration of the pandemic (MVPA: pre-pandemic: 194.2 ± 5.2 min, post-pandemic: 176.7 ± 5.0 min, p < 0.001; LPA: pre-pandemic: 1,000.5 ± 17.0 min, post-pandemic: 874.1 ± 15.6 min, p < 0.001; steps: pre-pandemic: 48,625 ± 745 steps, post-pandemic: 43,395 ± 705 steps, p < 0.001). However, 6 weeks following pandemic declaration, MVPA (week 6: 204.4 ± 5.4 min, p = 0.498) had returned to pre-pandemic levels. LPA (week 6: 732.0 ± 14.3 min, p = < 0.001) and steps (week 6: 41,946 ± 763, p < 0.001) remained significantly lower than pre-pandemic levels at week 6.Interpretation: Although MVPA returned to pre-pandemic levels, significant and sustained declines in incidental LPA and steps were observed. Attenuating the loss of incidental physical activity should be a public health priority in response to future pandemics or a second wave of a COVID-19 infection, as it may have significant long-term implications for the physical and mental health of Canadians.

Background: This study explored the association between inactive time and measures of adiposity, clinical parameters, obesity, type 2 diabetes and metabolic syndrome components. It further examined the impact of reallocating inactive time to time in bed, light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) on cardio-metabolic risk factors, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. Methods: This is a cross-sectional analysis of baseline data from 2189 Caucasian men and women (age 55-75 years, BMI 27-40 Kg/m(2)) from the PREDIMED-Plus study (http://www.predimedplus.com/). All participants had >= 3 components of the metabolic syndrome. Inactive time, physical activity and time in bed were objectively determined using triaxial accelerometers GENEActiv during 7 days (ActivInsights Ltd., Kimbolton, United Kingdom). Multiple adjusted linear and logistic regression models were used. Isotemporal substitution regression modelling was performed to assess the relationship of replacing the amount of time spent in one activity for another, on each outcome, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. Results: Inactive time was associated with indicators of obesity and the metabolic syndrome. Reallocating 30min per day of inactive time to 30 min per day of time in bed was associated with lower BMI, waist circumference and glycated hemoglobin (HbA1c) (all p-values < 0.05). Reallocating 30 min per day of inactive time with 30 min per day of LPA or MVPA was associated with lower BMI, waist circumference, total fat, visceral adipose tissue, HbA1c, glucose, triglycerides, and higher body muscle mass and HDL cholesterol (all p-values < 0.05). Conclusions: Inactive time was associated with a poor cardio-metabolic profile. Isotemporal substitution of inactive time with MVPA and LPA or time in bed could have beneficial impact on cardio-metabolic health., The PREDIMED-Plus trial was supported by the official funding agency for biomedical research of the Spanish government, ISCIII through the Fondo de Investigacion para la Salud (FIS), which is co-funded by the European Regional Development Fund (four coordinated FIS projects led by Jordi Salas-Salvado and Josep Vidal, including the following projects: PI13/00673, PI13/00492, PI13/00272, PI13/01123, PI13/00462, PI13/00233, PI13/02184, PI13/00728, PI13/01090, PI13/01056, PI14/01722, PI14/00636, PI14/00618, PI14/00696, PI14/01206, PI14/01919, PI14/00853, PI14/01374, PI16/00473, PI16/00662, PI16/01873, PI16/01094, PI16/00501, PI16/00533, PI16/00381, PI16/00366, PI16/01522, PI16/01120, PI17/00764, PI17/01183, PI17/00855, PI17/01347, PI17/00525, PI17/01827, PI17/00532, PI17/00215, PI17/01441, PI17/00508, PI17/01732, PI17/00926); the Especial Action Project entitled: Implementacion y evaluacion de una intervencion intensiva sobre la actividad fisica Cohorte PREDIMED-PLUS grant to Jordi Salas-Salvado; the European Research Council grant (Advanced Research Grant 2013-2019; 340918) to Miguel Angel Martinez-Gonzalez; the Recercaixa grant to Jordi Salas-Salvado (2013ACUP00194); grants from the Consejeria de Salud de la Junta de Andalucia (PI0458/2013; PS0358/2016; PI0137/2018); the PROMETEO/2017/017 grant from the Generalitat Valenciana; Grant of support to research groups no. 35/2011 (Balearic Islands Gov. & FEDER funds) to Catalina M. Mascaro and Josep A. Tur; FPU Programme, PhD fellowship (Spanish Ministry of Science, Innovation & Universities) to Catalina M. Mascaro; the Astra Zeneca Young Investigators Award in Category of Obesity and Diabetes 2017 to Dora Romaguera; Juan de la Cierva-formacion research grant (FJCI-2015-24058) of the Spanish Ministry of Economy, Industry and Competitiveness and European Social Funds to Jadwiga Konieczna; the 'FOLIUM' programme within the FUTURMed project from the Fundacion Instituto de Investigacion Sanitaria Illes Balears (financed by 2017annual plan of the sustainable tourism tax and at 50% with charge to the ESF Operational Program 2014-2020 ofthe Balearic Islands) to Jadwiga Konieczna. JR17/00022 contract to Olga Castaner from ISCIII. CIBERobn (Centros de Investigacion Biomedica en Red: Obesidad y Nutricion), CIBEResp (Centros de Investigacion Biomedica en Red: Epidemiologia y Salud Publica) and CIBERdem (Centros de Investigacion Biomedica en Red: Diabetes y Enfermedades). None of the funding sources took part in the design, collection, analysis or interpretation of the data and in writing the manuscript, or in the decision to submit the manuscript for publication.

Background Sedentary behaviour (SB) is associated with adverse health outcomes in the general population. Replacing sedentary time with light intensity physical activity (LPA) has been linked with improvements in all-cause and cardiovascular disease mortality in adults. People with Rheumatoid Arthritis (RA) typically spend long periods of time sedentary, but the health consequences of 'too much sitting', and possible benefits of LPA, have not been fully explored in this population. Moreover, little is known regarding the determinants of these behaviours among people living with RA, and such knowledge is required for the development of effective behavioural interventions. Aims To examine longitudinal relationships between: 1) objectively-assessed SB/LPA with health outcomes in RA, 2) hypothesised determinants of SB/LPA with objectively-assessed SB/LPA in RA. Methods This longitudinal study will secure assessments at baseline (Time 1) and 6-month follow-up (Time 2) from RA patients. At both time points, physical assessments will be undertaken, and questionnaires administered to measure physical (e.g., percentage body fat, disease activity, physical function, pain) and psychological (e.g., depression, anxiety, vitality) health outcomes. Additional questionnaires will be administered to establish hypothesised determinants (i.e., psychosocial, individual differences, and physical environmental). Participants will wear the ActiGraph GT3X accelerometer and activPAL3μTM for 7 days to objectively measure SB and LPA. Discussion Findings will elucidate the health correlates of SB in RA, as well as the relevance of interventions targeting reductions in SB by promoting LPA. Results will also assist in identifying intervention targets (i.e., determinants), with the potential to encourage SB change in RA.

Background Participation in physical activity may improve psychological well-being among people with Rheumatoid Arthritis (RA). This study examined the implications of autonomy support for physical activity, on objectively assessed light physical activity (LPA) engagement, and in turn, psychological well-being in RA. In addition, the role of lower-limb functional disability in these associations was investigated. Methods RA patients (n = 50) completed questionnaires assessing 1) autonomy support for physical activity [from a patient-specified important other], 2) functional disability to ‘rise’ and ‘walk’ (functional disabilityRW), 3) depressive symptoms, and 4) subjective vitality. Levels of LPA [100–2019 counts/minute], were calculated from 7 days of accelerometry. Results Path analysis supported a model (χ2 (2) = 2.44, p = 0.30, CFI = 0.99, SRMR = 0.05, RMSEA = 0.07) in which important other autonomy support for physical activity significantly and positively predicted LPA engagement. In turn, LPA was significantly and positively associated with subjective vitality, and significantly and negatively linked to depressive symptoms. These associations were observed independently of adverse direct relationships between functional disabilityRW with depressive symptoms and subjective vitality. Conclusions Important other autonomy support for physical activity may hold positive consequences for LPA engagement and related psychological well-being in RA, independent of the negative effects of lower-limb functional disability.

Though we know physical activity (PA) decreased while sedentary behavior (SB) increased compared to that before the COVID-19 pandemic, little is known about subsequent changes in PA and SB throughout one year in the post-pandemic era. This study aimed to examine the changes in PA and SB in a sample of Chinese young adults using a four-wave repeated-measure design during the pandemic. A total of 411 participants provided self-reported data of sociodemographic characteristics (e.g., sex, age), PA, and SB. Nonparametric tests and generalized estimating equations were conducted. Results revealed significant changes in moderate to vigorous PA (MVPA), light PA (LPA), and SB. The MVPA of Wave 1, 2, and 3 was significantly less than that of Wave 4 (p &lt, 0.001), the LPA of Wave 1 and 2 was significantly less than that of Wave 4, the SB of Wave 1 was significantly more than that of Wave 4 (p &lt, 0.05). Being female was the only predictor of changes in MVPA (Beta = −0.311, p&lt, 0.001). Being female (Beta = 0.115, p = 0.003) and perceived family affluence (Beta = −0.059, p&lt, 0.001) were predictors of changes in SB. As such, PA was less, while SB was more during the early stages of the pandemic. With the progress of the pandemic stages, health behaviors in young adults have been gradually improved. Sex and perceived family affluence were two important factors in predicting health behaviors. Our results can inform efficient policies or interventions in the COVID-19 era and future similar public health events.

Background/Objectives The aim of this study was to examine the effect of physical activity (PA) and sedentary behaviour (SB) on body mass index (BMI) and fat mass index (FMI) in children over the course of five years and identify potential bi-directional associations. Subjects/Methods Data were drawn from the EU Childhood Obesity Project (CHOP). PA and SB were measured with the SenseWear Armband 2 at the ages of 6 (T1), 8 (T2) and 11 (T3) years. Height and weight were measured and BMI was calculated at each time point, resulting in 1254 complete observations from 600 children. Bio impedance analysis was used to measure body fat mass and eventually calculate FMI. To examine the longitudinal association between PA/SB and BMI/FMI as well as to account for repeated measure on these children, mixed model analysis was employed. Results Higher levels of total PA and moderate-to-vigorous PA (MVPA) were associated with lower BMI and FMI and higher SB with higher BMI and FMI over the five year period. When looking at the age dependent effects, negative associations of MVPA (βMVPA x age: − 0.05, 95% confidence interval (CI): − 0.09 – -0.01, p = 0.007) and positive associations of SB (βSB x age: 0.04, 95% CI: 0.02–0.06, p

The aim of this study was to determine the relationship between bone mass (BM) and physical activity (PA) and sedentary behavior (SB) according to frailty status and sex using compositional data analysis. We analyzed 871 older people with an adequate nutritional status. Fried criteria were used to classify by frailty status. Time spent in SB, light intensity PA (LPA) and moderate-to-vigorous intensity PA (MVPA) was assessed from accelerometry for 7 days. BM was determined by dual-energy X-ray absorptiometry (DXA). The combined effect of PA and SB was significantly associated with BM in robust men and women (p &le, 0.05). In relation to the other behaviors, SB was negatively associated with BM in robust men while BM was positively associated with SB and negatively with LPA and MVPA in robust women. Moreover, LPA also was positively associated with arm BM (p &le, 0.01). Finally, in pre-frail women, BM was positively associated with MVPA. In our sample, to decrease SB could be a good strategy to improve BM in robust men. In contrast, in pre-frail women, MVPA may be an important factor to consider regarding bone health.

Background:Although moderate-to-vigorous physical activity (MVPA) is mainly recommended for glucose control, light physical activity (LIPA) may also have the potential to induce favorable changes. We investigated sedentary time (SED) substitution with equal time in LIPA and MVPA, and the association with markers of glucose regulation and insulin sensitivity after stratification by waist circumference, fitness and fasting glucose levels.Methods:A total of 654 men and women, 50 to 64 years, from the SCAPIS pilot study were included. Daily SED, LIPA and MVPA were assessed using hip-worn accelerometers. Fasting plasma glucose, insulin and HOMA-IR were determined.Results:Substituting 30 min of SED with LIPA was significantly associated with 3.0% lower fasting insulin values and 3.1% lower HOMA-IR values, with even lower levels when substituting SED with MVPA. Participants with lower fitness and participants with high fasting glucose levels benefited significantly more from substituting 30 min of SED with LIPA compared with participants with normal to high fitness levels and participants with normal glucose levels, respectively.Conclusions:LIPA, and not only MVPA, may have beneficial associations with glucose regulation. This is of great clinical and public health importance, not least because it may confer a higher compliance rate to regular PA.

Exergaming has been observed to be a viable supplemental approach in promoting physical activity (PA) among children. However, whether sex differences in PA and sedentary behaviors exist during exergaming is inconsistent. Thus, this study aimed to quantify, via accelerometry, young children&rsquo, s PA and sedentary behaviors during exergaming as well as examine sex differences in these PA and sedentary behaviors during gameplay. In total, 121 first- and second-grade children (mean age = 6.89 &plusmn, 0.9 years, 73 girls) were included in the analysis. Children were a part of a large 18-week parent study. Children wore ActiGraph GT1M accelerometers during exergaming play, with four measurements purposively selected from the 28 total exergaming sessions to capture children&rsquo, s PA and sedentary behaviors during exergaming play. Outcome variables included mean percentages of time spent in moderate-to-vigorous PA (MVPA), light PA (LPA), and sedentary behavior during each exergaming session. One-way ANOVA was performed to determine whether there were differences in the percentage of time engaged in MVPA, LPA, and sedentary behavior during exergaming by sex. Accelerometry data indicated that children&rsquo, s mean percentage of exergaming time spent in MVPA, LPA, and sedentary behavior were 19.9%, 32.9%, and 47.2%, respectively. However, no sex differences were present. Observations in this study indicated that boys and girls have similar PA levels during exergaming and suggests that features inherent to exergaming may assist in PA promotion among both sexes.

Background During a 24-h day, each given period is spent in either sedentary behaviour, sleeping, light physical activity (LPA), or moderate-to-vigorous physical activity (MVPA). In epidemiological research most studies have traditionally analysed the associations of these behaviours in isolation from each other; that is, without taking into account the displacement of time spent in the remaining behaviours. In recent years, there has been a growing interest in exploring how all the behaviours across the energy expenditure spectrum influence health outcomes. A statistical model used to investigate these associations is termed an isotemporal substitution model (ISM). Considering the increasing number of ISM-based studies conducted in all age groups, the present paper aimed to: (i) review and summarise findings from studies that employed ISM in sleep, sedentary behaviour, and physical activity research; (ii) appraise the methodological quality of the studies; and (iii) suggest future research directions in this area. Methods A systematic search of ten databases was performed. The Newcastle–Ottawa scale was used to assess the methodological quality of the included studies. Results Fifty-six studies met the inclusion criteria, all being of moderate or high methodological quality. Associations were reported for exchanged time varying from one minute to 120 min/day across the studies, with 30 min/day being the most common amount of time reallocated. In total, three different ISM methodologies were used. The most commonly studied health outcomes in relation to isotemporal substitutions were mortality, general health, mental health, adiposity, fitness, and cardiometabolic biomarkers. It seems that reallocations of sedentary time to LPA or MVPA are associated with significant reduction in mortality risk. Current evidence appears to consistently suggest that reductions in mortality risk are greater when time spent sedentary is replaced with higher intensities of physical activity. For adiposity, it seems that reallocating sedentary time to physical activity may be associated with reduced body mass index, body fat percentage, and waist circumference in all age groups, with the magnitude of associations being greater for higher intensities of physical activity. While there is a relatively large body of evidence reporting beneficial associations between the reallocation of time from sedentary behaviour to LPA or MVPA and cardiometabolic biomarkers among adults, there is a lack of studies among children, adolescents, and older adults. Although some studies investigated general health, mental health, and fitness outcomes, further investigation of these topics is warranted. In general, it seems that the strongest association with health outcomes is observed when time is reallocated from sedentary behaviour to MVPA. Most studies did not account for sleep time, which is a major limitation of the current evidence. Conclusions The current evidence indicates that time reallocation between sleep, sedentary behaviour, LPA, and MVPA may be associated with a number of health outcomes. Future studies should employ longitudinal designs, take into account all movement behaviours, and examine a wider range of health, psychological, social, economic, and environmental outcomes. Electronic supplementary material The online version of this article (10.1186/s12966-018-0691-3) contains supplementary material, which is available to authorized users.

Background: Although emerging research is demonstrating the potential health impact of exergaming, investigations have primarily been conducted in laboratory settings among small samples with short-term interventions. Information on the effectiveness of exergaming in underserved children's objective physical activity (PA) in population-based settings is also scarce. Moreover, most empirical studies have only included 1 type of exergame in the intervention. Therefore, this study's purpose was to investigate the long-term impact of a multigame exergaming intervention among underserved children integrated within school curricula. Specifically, this study examined the effect of exergaming on children's accelerometer-determined sedentary behavior (SB), light PA, moderate-to-vigorous PA (MVPA), and energy expenditure (EE) over 2 years as compared with regular physical education (PE) classes. Methods: A total of 261 second- and third-grade children (134 girls, 127 boys; mean age 8.27 years) were recruited from 2 Texas elementary schools. Children's pre-test 3-day SB, light PA, MVPA, and EE at school were assessed in the fall of 2012. Participants were assigned to 1 of 2 groups: (1) exergaming/PE group (125 min weekly of exergaming-based PA program) and (2) comparison group (125 min weekly of PE). PA (SB, light PA, and MVPA) and EE outcome variables were assessed again in 2013 (post-test) and 2014 (follow-up). Results: Significant time effects were observed for SB (F(1, 162) = 25.0, p 0.05, η2 = 0.004). Subsequent pairwise comparisons revealed significant increases from pre- to post-test for light PA (p 0.05). Conversely, significant decreases occurred in light PA (p

peer-reviewed Introduction: Sedentary behavior (SB) research has relied on accelerometer thresholds to distinguish between sitting/lying time (SLT) and light-intensity physical activity (LIPA). Such methods may misclassify SLT, standing time (StT), and LIPA. This study examines the association between directly measured SB, physical activity (PA), and adiposity in an adolescent female sample. Methods: Female adolescents (n = 195; mean age, 15.7 yr (SD, 0.9)) had body mass index (BMI) (median, 21.7 kg.m(-2) (interquartile range, 5.2 kg.m(-2))) and four-site sum of skinfolds (median, 62.0 mm; interquartile range, 37.1 mm) measured and wore an activPAL (TM) activity monitor for 7 d. SLT, StT, breaks in SLT, and bouts of SLT = 30 min were determined from activPAL outputs. A threshold of 2997 counts per 15 s determined moderate-to-vigorous PA. All remaining time was quantified as LIPA. Mixed linear regression models examined associations between PA variables, SB variables, and adiposity. Results: Participants spent a mean of 65.3% (SD, 7.1) of the waking day in SLT, 23.0% (SD, 5.3) in StT, 5.6% (SD, 1.5) in LIPA, and 6.1% (SD, 2.4) in moderate-to-vigorous PA. Significant effects for the percentage of LIPA (which excluded StT) with both BMI (beta = -4.38, P = 0.0006) and sum of skinfolds (beta = -4.05, P = 0.006) were identified. Significant effects for breaks in SLT with BMI (beta = -0.30, P = 0.04) were also observed. No additional significant associations were found between activity measures and adiposity. Conclusions: Increased LIPA (excluding StT) and breaks in SLT were negatively associated with adiposity in this sample, independent of age. Interventional work should examine whether reducing SLT through breaks and increasing LIPA may prevent increases in adiposity in adolescent females. ACCEPTED peer-reviewed

Background This pragmatic evaluation investigated the effectiveness of the Children’s Health, Activity and Nutrition: Get Educated! (CHANGE!) Project, a cluster randomised intervention to promote healthy weight using an educational focus on physical activity and healthy eating. Methods Participants (n = 318, aged 10–11 years) from 6 Intervention and 6 Comparison schools took part in the 20 weeks intervention between November 2010 and March/April 2011. This consisted of a teacher-led curriculum, learning resources, and homework tasks. Primary outcome measures were waist circumference, body mass index (BMI), and BMI z-scores. Secondary outcomes were objectively-assessed physical activity and sedentary time, and food intake. Outcomes were assessed at baseline, at post-intervention (20 weeks), and at follow-up (30 weeks). Data were analysed using 2-level multi-level modelling (levels: school, student) and adjusted for baseline values of the outcomes and potential confounders. Differences in intervention effect by subgroup (sex, weight status, socio-economic status) were explored using statistical interaction. Results Significant between-group effects were observed for waist circumference at post-intervention (β for intervention effect =−1.63 (95% CI = −2.20, -1.07) cm, p