Consumption of edible insects and insect-based foods: A systematic review of sensory properties and evoked emotional response.

Low consumer acceptance of edible insects and insect-based products is one of the main barriers to the successful implementation of entomophagy in Western countries. This rejection is mainly caused by consumers' negative emotional responses, psychological/personality traits, and attitudes toward food choices. However, as the role of intrinsic product characteristics on such food choices has not been adequately studied, a systematic review was conducted following the PRISMA method, to analyze studies that have assessed hedonic evaluations, sensory profiling, or emotional responses to edible insects or insect-based products. The majority of studies performed with whole insects and insect flour highlight that insect-based products are more negatively evaluated than control products. Although the sensory properties of insects are affected by species and processing conditions, they are generally negative across sensory dimensions. In particular, insects and insect-based products are generally associated with odor and flavor/taste attributes that are related to old/spoiled food. These negative attributes can be linked to the fat fraction of edible insects, with insect oils being very negatively evaluated by consumers. On the other hand, defatted fractions and deodorized oils are not associated with these negative attributes, further supporting the hypothesis that the fat fraction is responsible for the negative odor and flavor/taste attributes. However, there is still a lack of studies assessing the sensory profile of edible insects and insect-based products, as well as consumers' emotional responses to their consumption. Future studies should focus on the effects of different processing conditions, products incorporating insect fractions (namely protein concentrates/isolates and defatted fractions), and evaluation by target consumer groups.

Back pain in children and adolescents: a cross-sectional study.

PURPOSE: Back pain is a growing problem worldwide, not only in adults but also in children. Therefore, it is becoming increasingly important to investigate and understand the factors that influence the early onset of back pain. The aim of this study was to determine the prevalence of back pain in children and adolescents and to identify predisposing risk factors and protective factors. METHODS: A cross-sectional study was conducted between October and December 2019 in schools from northern Portugal, evaluating 1463 students aged 9 to 19 years, of both genders. The instruments used were the Spinal Mouse® to assess posture, the Inbody 230® to assess body composition, an online questionnaire to characterize the sample and back pain, and the FITescola® battery test to access physical fitness. RESULTS: Half of the subjects experienced back pain at least once in their lifetime. The most frequently mentioned were lumbar spine and thoracic spine, mostly with mild or moderate pain intensities. Age, female gender, percent body fat, prolonged smartphone and computer use, hyperkyphosis, and the lateral global spine tilt to the left side are all factors with higher relative risk of back pain. Practicing physical activity or sports regularly and video games have a protective effect. CONCLUSION: The prevalence of back pain in children and adolescents is very high: The study enhances the case for protective factors such as physical activity habits or video games while reinforcing risk factors such as percent body fat, prolonged smartphone or computer use, and posture.

Results from Portugal's 2022 report card on physical activity for children and youth.

Background: The purpose of this study is to update results of Portuguese's Report Card on Physical activity (PA) for Children and Adolescents. Methods: The grades were assigned by results derived from the PA and Fitness in Portugal 2021 Portuguese Report Card and corresponds to the third report for the Portuguese children and adolescents. It includes indicators of PA and sedentary behavior (SB) that are common to the GLOBAL matrix 4.0: Overall Physical Activity, Organized Sport and Physical Activity, Active Play, Active Transportation, Sedentary Behaviors, Family and Peers, School, Community and the Environment, Government and Physical Fitness. The search focused on published national evidence/data sources (academia, NGO, governmental) from end 2018 onwards excluding data obtained during the covid-19 pandemic. Results: The grades were assigned as follows: Overall PA (D-), Organized Sport Participation (C-), Active Play (D+), Active Transportation (D-), Sedentary behaviors (C+), Physical Fitness (C), Family and Peers (B), School (A), Community and Environment (B), and Government (B). Conclusion: In line with previous Portuguese Report Cards, a large proportion of Portuguese children and adolescents are not sufficiently active nor fit enough setting urgency for effective strategies. Particular attention should be given to Active play, Active transport and Organized Sports Participation has their grades have decreased. Some actions in selected indicators as Governmental and policy seems promising however results weren't seen yet. Despite the strong support of schools with mandatory curricula in PE no correspondent change is observed in fitness or PA, so more research is needed to find why.

Balance and Posture in Children and Adolescents: A Cross-Sectional Study.

Balance and posture are two topics that have been extensively studied, although with some conflicting findings. Therefore, the aim of this work is to analyze the relationship between the postural angles of the spine in the sagittal plane and the stable static balance. A cross-sectional study was conducted with children and adolescents from schools in northern Portugal in 2019. An online questionnaire was used to characterize the sample and analyze back pain. Spinal postural angle assessment (pelvic, lumbar, and thoracic) was performed using the Spinal Mouse®, while stabilometry assessment was performed using Namrol® Podoprint®. Statistical significance was set as α = 0.05. The results showed that girls have better balance variables. There is a weak correlation between the anthropometric variables with stabilometry variables and the postural angles. This correlation is mostly negative, except for the thoracic spine with anthropometric variables and the lumbar spine with BMI. The results showed that postural angles of the spine are poor predictors of the stabilometric variables. Concerning back pain, increasing the postural angle of the thoracic spine increases the odds ratio of manifestation of back pain by 3%.

Cardiorespiratory fitness, but not physical activity, is associated with academic achievement in children and adolescents.

BACKGROUND: Cardiorespiratory fitness (CRF) and physical activity (PA) seem to have positive effects on academic achievement (AA), although in most studies, objective methods of assessment have not been used. AIM: To examine the associations of CRF and PA with AA. SUBJECTS AND METHODS: A sample of 640 youngsters (10-18 years) participated in this cross-sectional study. CRF was estimated with the 20-metre shuttle run test and PA was measured using accelerometers. School grades were used to describe AA using mathematics and native language final grades. The relationship between CRF and PA with AA was analysed using ANCOVA. RESULTS: Results show a significant effect of CRF levels on native language grades, after adjustment for confounders [F(3,414) = 3,99 p < 0.05], but not for mathematics [F(3,360) = 0.95 p > 0.05]. No significant effects of PA levels on AA were found. CONCLUSIONS: CRF is associated with moderate-to-vigorous PA (MVPA) and higher levels of CRF may influence AA. CRF is positively correlated with MVPA, suggesting that higher amounts of MVPA might improve CRF and indirectly influence AA. Since CRF is dependent on higher intensities of PA, we can suggest a focus on implementing improvement strategies to increase the intensity of physical education lessons.

Versatility of Chitosan-Based Biomaterials and Their Use as Scaffolds for Tissue Regeneration.

Chitosan is a naturally occurring polysaccharide obtained from chitin, present in abundance in the exoskeletons of crustaceans and insects. It has aroused great interest as a biomaterial for tissue engineering on account of its biocompatibility and biodegradation and its affinity for biomolecules. A significant number of research groups have investigated the application of chitosan as scaffolds for tissue regeneration. However, there is a wide variability in terms of physicochemical characteristics of chitosan used in some studies and its combinations with other biomaterials, making it difficult to compare results and standardize its properties. The current systematic review of literature on the use of chitosan for tissue regeneration consisted of a study of 478 articles in the PubMed database, which resulted, after applying inclusion criteria, in the selection of 61 catalogued, critically analysed works. The results demonstrated the effectiveness of chitosan-based biomaterials in 93.4% of the studies reviewed, whether or not combined with cells and growth factors, in the regeneration of various types of tissues in animals. However, the absence of clinical studies in humans, the inadequate experimental designs, and the lack of information concerning chitosan's characteristics limit the reproducibility and relevance of studies and the clinical applicability of chitosan.

Exercise intervention and cardiovascular risk factors in obese children. Comparison between obese youngsters taking part in a physical activity school-based programme with and without individualised diet counselling: the ACORDA project.

AIM: To determine the effects of a school-based exercise intervention programme on cardiovascular risk factors, including body fat (BF), metabolic profile and physical activity (PA) in children with and without individualised dietary counselling approach (IDC and WIDC). SUBJECTS AND METHODS: Forty-six overweight children from 6-16 years old (25 girls, 54.3%; age = 10.3 ± 2.8) of six schools took part in an 8-month interdisciplinary, school-based intervention programme. All children were engaged in PA classes, but only one group was exposed to individualised counselling. Blood pressure (BP), lipids and lipoproteins, accelerometer-based PA, percentage of body fat (%BF) and trunk fat (%TF) measures were taken before and after intervention. General Linear Model (Repeated Measures ANOVA) adjusted for age, maturation and height change was used to analyse the longitudinal effect of individualised counselling between two evaluations in each group. RESULTS: Favourable changes were observed for %BF, %TF, systolic BP and total cholesterol in the IDC group. Subjects WIDC only increased light and moderate-vigorous PA. In IDC, significant effects for time * group interactions were found for systolic BP, total cholesterol and LDL-cholesterol, indicating that counselling might add favourable changes in these markers, beyond those explained by PA and growth. CONCLUSION: School-based interventions can contribute to counteracting obesity in youth, particularly when individualised dietary counselling is provided. Therefore, the link between schools and professional counselling should be strengthened to ensure consolidated changes towards healthy behaviours.

Examining the utility of thresholds for aerobic fitness related to resting blood pressure and BMI in Portuguese children.

OBJECTIVES: This study examined the utility of the Ruiz et al. cut-points when examining body mass index (BMI) and resting blood pressure in young people. METHODS: Two hundred fifty-six children (154 girls and 102 boys) aged 7-16 years underwent assessment of BMI, physical maturation, resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) and cardiorespiratory fitness using breath by breath gas analysis during treadmill testing to exhaustion. RESULTS: Results from a series of 2 (fit vs. unfit) × 2 (gender) ways analysis of covariance, controlling for maturation indicated higher SBP in the unfit group compared to the fit group (P = 0.001), higher DBP in the unfit group compared to the fit group (P = 0.04) and higher BMI (in unfit) than fit children (P = 0.0001). Males had significantly higher BMI than females (P = 0.04). Maturation as a covariate was significantly and positively associated with SBP (P = 0.003), DBP (P = 0.004), and BMI (P = 0.001). CONCLUSIONS: This study suggests that the Ruiz et al. cut-points are valid in distinguishing between children with higher and lower BMI and resting BP values.

Adaptation, Update and Validation of the General Nutrition Questionnaire in a Portuguese Adolescent Sample.

This article describes the adaptation of the adult Portuguese version of the General Nutrition Knowledge Questionnaire (GNKQ) for adolescents, and its validation. Respondents were 1,315 adolescents, who completed the questionnaire in two phases. A subsample of 73 adolescents was used to measure test-retest reliability. Concurrent validity was tested using a sample of 32 dietetic students. The adapted version showed high internal consistency (Cronbach's alpha = 0.92), test-retest reliability (R = 0.71) and concurrent validity (U = 22766.0; p < .01). Adolescents' nutrition knowledge can now be assessed with a valid and reliable instrument. Future validation works of this or others questionnaires for children and elderly are warranted.

Is walking to school associated with improved metabolic health?

BACKGROUND: Active commuting to/from school is an important source of physical activity that has been declining over the past years. Although it is an affordable and simple way of increasing physical activity levels it is still unclear whether it has enough potential to improve health. Therefore, the aim of this cross sectional study was to examine the relationship between active commuting to/from school and metabolic risk factors in 10 to 12 year old children. METHODS: Participants were 229 adolescents, selected through consecutive sampling, (121 girls) with mean age of 11.65 (±0.73) years old from Porto, Portugal. Means of transport to/from school was accessed by asking: "How do you usually travel to school?" and "How do you usually travel from school?". Active commuting was considered if children reported at least one of the trips (to or from school) by active means. Total physical activity was obtained with Actigraph accelerometer for 7 consecutive days. Lipid profile measurements were conducted with Cholestech LDX® analyser. Waist circumference and blood pressure were measured by standard methods. The criteria for metabolic syndrome defined by International Diabetes Federation for children and adolescents were used. RESULTS: Adjusted binary logistic regression analysis suggested that walkers have higher odds to have a better waist circumference (OR = 2.64, 95% CI = 1.63-6.01) and better high density lipoprotein cholesterol (OR = 2.14, 95% CI = 1.01-4.52) profiles than non-active commuters, independent of moderate-to-vigorous physical activity. No associations were found for other metabolic risk factors. CONCLUSIONS: Exertions to increase and maintain walking to school may be particularly relevant as it is likely to have a positive impact on children's health and eventually decrease metabolic and cardiovascular diseases.

Cross validation of ROC generated thresholds for field assessed aerobic fitness related to weight status and cardiovascular disease risk in Portuguese young people.

OBJECTIVES: To examine the efficacy of aerobic fitness thresholds in predicting weight status and cardiovascular disease risk (CVD) in young people. METHODS: A cross-sectional school-based study was conducted on 414 Portuguese young people (235 girls and 179 boys) aged 10-16 years (Mean age ± SD = 13.6 ± 1. 8 years). Height and mass were assessed to determine body mass index (BMI). The 20 m multistage shuttle-fitness test (MSFT) was used as an estimate of aerobic fitness. Capillary blood sampling was used to determine: total cholesterol, triglycerides, high-, and low-density lipoprotein. These were combined with measures of systolic blood pressure as z-scores and summed to create a CVD risk score. RESULTS: Analysis of covariance, controlling for sexual maturation, indicated a significant main effect for BMI as a result of fitness category (P = 0.0001). When applied to CVD risk data, there was no difference between "fit" and "unfit" groups (P = 0.136). Subsequent receiver operating curve (ROC) analysis indicated significant diagnostic accuracy of 20 mMSFT performance for boys and girls (both P = 0.0001) with subsequent cut-offs of estimated VO2 peak of 49.5 ml kg(-1) min(-1) for girls and 47.7 ml kg(-1) min(-1) for boys. When applied to BMI and CVD risk data, there was a significant main effect as a result of fitness category for BMI (P = 0.0001) and CVD risk score (P = 0.0001). CONCLUSIONS: Recently established cut-points proposed by Boddy et al. (Boddy et al. [2012]: PLoS One 7(9): e45755) show validity in distinguishing between weight status but not CVD risk in Portuguese young people. Alternative ROC generated cut points significantly predicted BMI and CVD risk in this sample.

Associations between sports participation, levels of moderate to vigorous physical activity and cardiorespiratory fitness in childrenand adolescents.

The purpose of this study was to analyse the associations between sports participation, levels of moderate to vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF). The study comprised 310 participants (183 girls and 127 boys) aged 11-18 years. Sports participation was assessed by questionnaire and habitual physical activity (PA) was measured objectively with accelerometers. The 20-m shuttle-run test was used to estimate CRF. Logistic regression analyses were carried out with CRF as the outcome. The odds ratio (OR) for being fit was greater for those who comply with 60 min · day(-1) in MVPA (OR = 2.612; 95%confidence interval [CI] = 1.614-4.225) in comparison with those who do not. Participation in competitive sports at club levels increased the chances of being fit (OR = 13.483; 95%CI = 4.560-39.864), independently of MVPA levels. There were positive and significant trends in CRF and objectively measured PA across the levels of engagement in competitive sports (P < 0.05). Concluding, participation in competitive sports at club level is more effective than other organised or non-organised sports to reach healthier levels of CRF and recommend levels of MVPA.

Associations between body mass index, waist circumference and body shape index with resting blood pressure in Portuguese adolescents.

BACKGROUND: Elevated blood pressure (BP) in childhood and adolescence is associated with overweight and obesity. Recently a body shape index (ABSI) has been suggested as superior to body mass index (BMI, kg/m(2)) and waist circumference (WC) as a measure of disease risk. OBJECTIVE: To examine the association between ABSI, BMI, WC and BP in Portuguese adolescents and to consider the role of ABSI, BMI and WC when examining this issue in adolescents. METHODS AND PROCEDURES: Height, body mass, WC and resting blood pressure were assessed in 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years. RESULTS: ABSI, BMI and WC were all significantly related to both SBP and DBP (all p = 0.001 or better). ABSI, BMI and WC were all significant predictors of SBP and DBP for the whole sample and when analysed in separate gender groups (p = 0.001 or better in all cases). However, in all cases ABSI was a better predictor of BP than BMI or WC. CONCLUSIONS: Although BMI and WC significantly predict resting BP in adolescents, the use of ABSI explained a greater amount of the variance in BP in this population. When examining the effect of weight status on BP, researchers should consider use of ABSI alongside BMI.

Cardiorespiratory fitness and TV viewing in relation to metabolic risk factors in Portuguese adolescents.

BACKGROUND: The purpose of this study was to examine whether adolescents who have high levels of cardiorespiratory fitness (CRF) co-existing with low levels of television (TV) viewing present a better metabolic risk profile compared to their low fit and high TV viewing counterparts. SUBJECTS AND METHODS: A total of 372 students (aged 12-15 years old) comprised the sample of this study. Anthropometric data (body mass index and waist circumference) was collected. CRF was calculated based upon the 20 metres shuttle run test. A questionnaire was used to estimate weekly TV viewing. Information about biological maturity and parental education was collected. Participants were then categorized into one of four category profiles according to the scores they achieved: low TV-Fit; high TV-Fit; low TV-Unfit and high TV-Unfit. Metabolic risk score (MRS) was calculated based on the sum of the Z-scores of all the metabolic variables analysed. RESULTS: Logistic regression analyses indicated that the high TV-Unfit group was almost 3-times more likely to be assigned to the high MRS group (OR = 2.85, 95% CI = 1.08-7.50) compared to their low TV-Fit group counterparts. CONCLUSIONS: The data showed that the high TV-Unfit group was associated with an increased metabolic risk in adolescents after adjustment for gender, age, biological maturity and parental education.

Dissemination, Implementation, and Evaluation of an Effective School-Based Intervention to Promote Physical Activity in Adolescents: A Study Protocol.

Adolescents around the world do not engage in sufficient physical activity and the Spanish context is no exception. Understanding the educational context as a complex system, school-based multi-level and multi-component interventions seem to be an effective strategy to reverse this trend. Moreover, a co-creational approach seems to facilitate the mobilization of community partnerships and the engagement of stakeholders in the intervention process. This study aims to describe the dissemination, implementation, and evaluation process of an effective school-based intervention program in another setting using the replicating effective programs framework and a co-participatory approach. This study will be conducted in two Spanish secondary schools located in the region of Aragon (experimental vs. control school) in a sample of adolescents in the second grade (13-14 years old). To evaluate the effectiveness, different health behaviors such as physical activity, sleep, sedentary time with screens, nutrition, and psychosocial variables will be quantitatively measured at baseline and after the implementation of the intervention. Qualitative methods will also be used to better understand the implementation process and the co-creation approach, as well as to provide insights into the sustainability of the intervention program. The current study has the potential to provide strong information about the dissemination, implementation, and evaluation process of school-based programs to promote healthy behaviors among adolescents.

Comparisons between inverted body mass index and body mass index as proxies for body fatness and risk factors for metabolic risk and cardiorespiratory fitness in Portuguese adolescents.

OBJECTIVES: To compare inverted body mass index (iBMI, cm(2) /kg) and body mass index (BMI, kg/m(2) ) as predictors of body fatness, metabolic risk, and cardiovascular fitness in adolescents. METHODS: A cross-sectional school-based study was conducted on 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years. Height and body mass were assessed to determine iBMI and BMI, percent body fatness was determined from skinfold measures (tricep, subscapular) using the Slaughter et al. (1988: Hum Biol 60: 709-723) regression equation and cardiorespiratory fitness (CRF) was assessed using the 20-m shuttle run test. Capillary blood sampling was used to determine: Total cholesterol, triglycerides, high, and low density lipoprotein. These were combined with measures of systolic blood pressure and waist circumference as z-scores. Metabolic risk (MRS) was constructed by summing the z-scores. RESULTS: iBMI and BMI were both significantly related to percent body fatness, CRF and MRS (all P = 0.005 or better). BMI was not normally distributed (P = 0.0001), whereas iBMI was (P > 0.05). Regression analysis identified that iBMI and BMI, both alongside for age, were significant predictors of percent body fatness, CRF and MRS (all P = 0.005 or better). Compared with BMI, iBMI was a similar predictor of CRF, MRS and body fatness. CONCLUSIONS: iBMI offers a biologically sound alternative to BMI to assess the effect of weight status on MRS and CRF in adolescents and allows appropriate use of parametrical statistical techniques without changing the conclusions drawn from such data.

Normative and criterion-related standards for shuttle run performance in youth.

The purpose of this study was to calculate and validate reference standards for the 20-m shuttle run test (SR) in youths aged 10-18 years. Reference standards based on the number of completed SR laps were calculated by LMS method in a reference group of 5559 students. Cut-off values for SR laps were determined and tested by ROC curve analysis in a validation group (633 students), from which waist circumference, HDL-cholesterol, triglycerides, fasting glucose and mean arterial pressure were assessed to calculate a metabolic risk score, later dichotomized in low and high metabolic risk (HMRS). The accuracy of SR laps standards was significant for girls (AUC = 0.66; 95% CI = 0.58-0.74; p < .001) and boys (AUC = 0.71; 95% CI = 0.62-0.79; p < .001) for identifying subjects at HMRS. The 40th percentile was the best cut-off for SR laps in girls (SENS = 0.569; 1-SPEC = 0.330) and boys (SENS = 0.634; 1-SPEC = 0.266). New SR laps reference standards are able to discriminate metabolic risk levels, and may provide a valuable tool for early prevention of cardiovascular risk factors.

Effect of ceramic surface treatment on the shear bond strength of a resin cement to different ceramic systems.

This study evaluated three surface treatments and their effect on the shear bond strength between a resin cement and one of three ceramics. The ceramic surfaces were evaluated with scanning electron microscopy (SEM) as well. Specimens were treated with 50 µm aluminum oxide airborne particles, 10% hydrofluoric acid etching, or a combination of the two. Using a matrix with a center hole (5.0 mm x 3.0 mm), the ceramic bonding areas were filled with resin cement following treatment. The specimens were submitted to thermal cycling (1,000 cycles) and the shear bond strength was tested (0.5 mm/minute). The failure mode and the effect of surface treatment were analyzed under SEM. Data were submitted to ANOVA and a Tukey test (α = 0.05). Duceram Plus and IPS Empress 2 composite specimens produced similar shear bond strength results (p > 0.05), regardless of the treatment method used. Hydrofluoric acid decreased the shear bond strength of In-Ceram Alumina specimens. For all materials, surface treatments changed the morphological surface. All treatments influenced the shear bond strength and failure mode of the ceramic/resin cement composites.

Cardiorespiratory Fitness, Obesity and Physical Activity in Schoolchildren: The Effect of Mediation.

There are only a few studies that have examined the interaction between physical activity (PA), cardiorespiratory fitness (CRF), and overweightness/obesity in adolescents, and these studies have shown some limitations. The objective of this study was to examine whether the association between PA (moderate-vigorous PA [MVPA], moderate PA [MPA], and vigorous PA [VPA]) and obesity is mediated by CRF. This cross-sectional study was conducted in six middle and high-schools in the Porto district (Portugal), comprising 632 children and adolescents. Fat mass (FM), CRF, MVPA, MPA, and VPA were assessed. The Process macro for SPSS was used. CRF was significantly associated with PA for both children and adolescents. Likewise, FM was negatively and significantly associated with CRF for both children (ß = -0.337) and adolescents (ß = -0.255). FM was associated with PA in children (MVPA: ß = -0.102; MPA: ß = -0.118; VPA: ß = -0.305) and adolescents (MVPA: ß: -0.103; MPA: ß = -0.082; VPA: ß = -0.204). The mediation analysis showed that the association between PA (MVPA//MPA/VPA) and obesity was mediated by CRF, in both children and adolescents, with a significant value in the Sobel test. Obesity is associated with CRF and MVPA, MPA, and VPA. However, CRF acted as a complete mediator between the association of obesity and PA.

Perception of the social and built environment and physical activity among Northeastern Brazil adolescents.

OBJECTIVE: To evaluate the association between levels of physical activity and perception of the social and built environmental in adolescents from Northeastern Brazil. METHODS: The sample comprised 2874 adolescents aged 14 to 19 years (57.8% females) enrolled in private or public secondary schools in the municipality of João Pessoa, Northeastern Brazil. Level of physical activity was measured by questionnaire. Perception of environmental characteristics was measured by means of fifteen questions rated on four-point Likert-type scales ranging from 1 ("strongly disagree") to 4 ("strongly agree"). The association between physical activity and perception of environmental characteristics was investigated using multivariate binary logistic regression. RESULTS: Multivariate analysis showed that adolescents living in neighborhoods where other adolescents were physically active (68.7% vs. 60.1%, OR=1.20; 95%CI: 1.05-1.56, among boys only) or who lived close to places they liked to frequent (71.8% vs. 53.4%, OR=1.96; 95%CI: 1.40-2.78 among boys; and 42.0% vs. 32.3% OR=1.33; 95%CI: 1.10-1.74 among girls) were more likely to be physically active. CONCLUSIONS: Adolescents with positive perceptions of certain environmental characteristics were more likely to be physically active. Environmental characteristics may relate differently to levels of physical activity among boys and girls.