Care seek behavior for low back pain in southern Brazil during the COVID-19 pandemic: a panel data analysis.

BACKGROUND: During the COVID-19 pandemic, people with low back pain (LBP) might have avoided seeking care for their pain. We aimed to investigate how the COVID-19 pandemic has affected LBP care seeking behavior among adults. METHODS: Data from four assessments of the PAMPA cohort were analyzed. Participants who reported experiencing LBP during wave one both before and during social restrictions (n = 1,753 and n = 1,712, respectively), wave two (n = 2,009), and wave three (n = 2,482) were included. We asked participants about sociodemographic, behavioral, and health factors and outcomes related to LBP. Poisson regression analyses were conducted, and data are presented as prevalence ratios (PR) and respective 95% confidence interval (95%CI). RESULTS: Overall, care seeking behavior decreased by half in the first months of restrictions, from 51.5% to 25.2%. Although there was an increase in care seeking behavior observed in the other two assessments (nearly 10 and 16 months after restrictions), it was insufficient to reach pre-pandemic levels. In the first months of restrictions, a similar scenario was observed for specific care, such as general practitioner and exercise professional care, with proportions of pre-pandemic levels reached after 10 and 16 months. Women were more likely to seek care for LBP 10 and 16 months after restrictions (PR 1.30 95%CI 1.11; 1.52, PR 1.22 95%CI 1.06; 1.39, respectively). Also, those participants who worked, were physically active, and reported pain-related disability and high pain levels were more likely to seek care at all time points assessed. CONCLUSION: Overall, care-seeking behavior for LBP significantly decreased in the first months of restrictions and increased in the following months; however, this behavior remained lower than pre-pandemic levels.

Short-term impact of COVID-19 pandemic on low back pain: data from the PAMPA Cohort, Brazil.

BACKGROUND: To evaluate the short-term impact of COVID-19 pandemic on low back pain (LBP) outcomes in southern Brazil. METHODS: Data from the PAMPA Cohort were analyzed. Adults were recruited between June and July 2020 in the Rio Grande do Sul state using online-based strategies. Participants responded a self-reported, online questionnaire on LBP with two timepoints: before (retrospectively) and during COVID-19 pandemic. We assessed LBP experience, LBP-related activity limitation (no/yes), and LBP intensity (0 to 10 [strongest pain]). RESULTS: From a total sample of 2,321 respondents (mean age: 37.6 ± 13.5; 75.4% women), the prevalence of LBP did not change significantly from before (74.7% [95%CI 72.3; 76.9]) to the first months of pandemic (74.2% [95%CI 71.9; 76.3]). However, an increased pain levels (ß: 0.40; 95%CI 0.22; 0.58) and a higher likelihood for activity limitation due to LBP was observed (PR 1.14; 95%CI 1.01; 1.29). Longitudinal analyzes showed that age, gender, BMI, chronic diseases, physical activity, and anxiety and depression symptoms, were associated with LBP in the first pandemic months. CONCLUSION: Although the prevalence of LBP did not change at the first months of COVID-19 pandemic, LBP-induced impairment in daily activities and pain intensity was higher when compared to before the pandemic.

External validation of a prediction model for estimating fat mass in children and adolescents in 19 countries: individual participant data meta-analysis.

OBJECTIVE: To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings. DESIGN: Individual participant data meta-analysis. SETTING: 19 countries. PARTICIPANTS: 5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment). MAIN OUTCOME MEASURES: The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R2, calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves. RESULTS: The model showed good predictive ability in non-UK populations of children and adolescents, providing R2 values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were <4 kg in 17 of the 19 settings. Pooled values (95% confidence intervals) of R2, calibration slope, and calibration-in-the-large were 88.7% (85.9% to 91.4%), 0.98 (0.97 to 1.00), and 0.01 (-0.02 to 0.04), respectively. Heterogeneity was evident in the R2 and calibration-in-the-large values across settings, but not in the calibration slope. Model performance did not vary markedly between boys and girls, age, ethnicity, and national income groups. To further improve the accuracy of the predictions, the model equation was recalibrated for the intercept in each setting so that country specific equations are available for future use. CONCLUSION: The UK based prediction model, which is based on readily available measures, provides predictions of childhood fat-free mass, and hence fat mass, in a range of non-UK settings that explain a large proportion of the variability in observed fat-free mass, and exhibit good calibration performance, especially after recalibration of the intercept for each population. The model demonstrates good generalisability in both low-middle income and high income populations of healthy children and adolescents aged 4-15 years.

Effects of two exercise programs on health-related fitness, quality of life and exercise enjoyment in adults with visual impairment: a randomized crossover trial.

BACKGROUND: So far there is no study comparing two distinct exercise interventions in people with visual impairment. This study aimed to evaluate the effects of two exercise programs on health-related fitness, quality of life, and exercise enjoyment in people with visual impairment. METHODS: Two exercise interventions were conducted: sports (i.e., Goalball, Football 5-a-side and Martial Arts) and functional training (i.e., Bodyweight exercises). Physical fitness was assessed by handgrip strength, flexibility, abdominal endurance, and cardiorespiratory fitness. The Physical Activity Enjoyment Scale (PACES) measured the pleasure in the practice of physical exercises, and the quality of life was measured by the WHOQOL-Bref. RESULTS: A significant time x group interaction terms were observed for flexibility (P < 0.001; Cohen d = 0.08), abdominal muscular endurance (P < 0.001; Cohen d = 0.15), and distance covered in the 6-min walk/run test (P = 0.018; Cohen d = 0.02). An improvement of 13.3% and 5.1% on the distance covered on the 6-min walk/run test after sports and functional training was also observed. CONCLUSION: The functional training program was reported as more pleasant for participants. Sports-related exercises and functional training improved health-related fitness and quality of life for people with visual impairment.

Physical activity and the incidence of depression during the COVID-19 pandemic in Brazil: Findings from the PAMPA cohort.

We examined the longitudinal association between physical activity (PA) and the incidence of self-reported diagnosed depression in adults in southern Brazil during the COVID-19 pandemic. Data from the PAMPA (Prospective Study About Mental and Physical Health) cohort was used. Data collection for baseline was carried out on June-July 2020, with two follow-up assessments taking place six months apart. An online, self-reported questionnaire assessed depression and PA. Depression was assessed by asking participants whether they were ever diagnosed with depression. We included 441 participants (women: 75.9%; mean age [SD]: 38.0 [13.5]) in southern Brazil. Over the follow-up, 21.8% (95% confidence interval [CI]: 18.1%-25.9%) were diagnosed with depression. Insufficiently active (<150 min per week of physical activity) (Incidence rate [IR]: 61.9; 95%CI: 39.5-102.4; p = 0.047) and active (≥150 min per week of physical activity) (IR: 50.4; 95%CI: 31.9-84.0; p = 0.015) participants had reduced IR of depression per 1000 persons-year at risk compared to inactive ones (0 min per week of physical activity) (IR: 99.9; 95%CI: 79.7-126.8). In the adjusted analyses, participants in the insufficient active (hazard ratio [HR]: 0.58; 95%CI: 0.34-0.98) and active (HR: 0.53; 95%CI: 0.31-0.93) group had a lower risk of developing depression than the inactive group. PA both at and out of home reduced the risk of incident depression (HR: 0.49; 95%CI: 0.25-0.98) compared to no physical activity. Endurance (HR: 0.52; 95%CI: 0.28-0.97) and endurance plus strengthening (HR: 0.40; 95%CI: 0.17-0.95) PA reduced the risk of incident depression compared to none. Being physically active during pandemic, regardless of the amount of PA practiced, reduced the incidence of depression in adults in southern Brazil.

Physical activity trajectory in the first 10 months of the COVID-19 pandemic in Southern Brazil: a follow-up study.

BACKGROUND: A continuous tracking of the PA level during the COVID-19 pandemic is important to understand how people's behaviour has varied along time. The aim of this study was to evaluate the physical activity (PA) trajectory over the first 10 months of the COVID-19 pandemic in the south of Brazil. METHODS: Data from three timepoints of the PAMPA Cohort were used, as follows: (1) pre-COVID-19 (retrospective); (2) Jun/Jul 2020; (3) Dec 2020/Jan 2021. Self-reported PA practice, frequency, duration, as well as place where activities were performed (at or out of home) were assessed. RESULTS: A reduction in any (from 68.7 to 47.7%), sufficient (from 41.5 to 22.1%) and out of home PA (from 59.4 to 30.1%) was observed from the first (pre-COVID-19) to the second (Jun/Jul 2020) timepoint, followed by an increase in the third timepoint (Dec 2020/Jan 2021) (60.1%, 37.9%, and 54.3% for any, sufficient, and out of home PA, respectively). The PA trajectory was similar, regardless of sex, educational level or income. Only any (p = 0.0007) and sufficient (p = 0.0012) PA showed significant interaction with time by sex. Female participants were less likely to engage in any (OR 0.45 95% CI 0.26; 0.77) and sufficient PA (OR 0.40 95% CI 0.24; 0.66). CONCLUSION: During the first 10 months of COVID-19 pandemic there was a marked fluctuation on PA pattern in adults from southern Brazil. An ongoing tracking of PA behaviour during COVID-19 pandemic is important to understand how this behaviour varies. Public policies should focus on increasing PA in a higher standard than pre-COVID levels.

Muscular and cardiorespiratory parameters of Brazilian professional futsal players: comparison between top national and regional level athletes

Abstract Aim: To compare muscular and cardiorespiratory parameters between Brazilian professional futsal athletes from different competitive levels (national versus regional). A secondary aim was to explore the correlation of physical fitness variables between both competitive levels. Methods: Twenty-two futsal players (24.7 ± 3.7 years), 11 from a regional team and 11 from a national team, were evaluated with countermovement jump test (lower limbs muscle power), square test (the speed with change direction), RSSA (anaerobic power), and YOYOIR1 (aerobic power). Tests were performed in the middle of the season for both teams. Results: The speed with change direction (p = 0.001) and mean anaerobic power (p = 0.04) were higher for national than the regional players. Sprint performance decreased similarly for national and regional level players (p < 0.001), but the latter had poorer performance (p = 0.044). From the fourth sprint on, sprints for the national level players were slower than the first three, while for the regional level players, each sprint speed was slower than the subsequent. A significant correlation was found between anaerobic power with jump height (r = −0.50; p = 0.01), speed with change direction (r=0.65; p = 0.001) and distance covered in the YOYOIR1 (r = −0.54; p = 0.01). Conclusion: National-level athletes were more agile and presented a higher mean anaerobic power than regional ones. Moreover, national-level athletes presented better performance along with repeated sprint tests, maintaining this performance for a longer time during the test.

Determinants of increased frequency of depressive and anxiety symptoms in exercise professionals during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease (COVID-19) pandemic has affected workers in different health services including exercise professionals (EP). The urgent need to adapt in-person to online activities might have led to increased frequency of anxiety and depressive symptoms. OBJECTIVE: We aimed to identify the determinants of aggravated depressive and anxiety symptoms in EP in southern Brazil during social distancing from the COVID-19. METHODS: A cross-sectional study was conducted with EP who worked at fitness centers, sports clubs, private schools, or at a public exercise program offered by the municipal council. We used an online-based, self-administered, adapted version of the Hospital Anxiety and Depression scale to compare symptoms of depression and anxiety pre- and during social distancing. RESULTS: Participants (n = 201) had a mean age of 32.7±8.0 years, with more than half being male, white, and having an university degree. We observed that 81%and 71%of respondents reported higher frequency in anxiety and depression symptoms, respectively, during social distancing than in the period before it. Physical education teachers, women, non-white professionals, and those with chronic disease were more likely to worsen anxiety symptoms. Women had higher odds to increased frequency in depressive symptoms. Physical activity and previous experience with internet-based tools for working activities reduced the risk of increased depressive symptoms. CONCLUSIONS: Sex, ethnicity, chronic diseases, educational level, physical activity, and experience with online tools were determinants for increased frequency of depression and anxiety symptoms in EP.

How has COVID-19 social distancing impacted physical activity patterns? Data from the PAMPA cohort, Brazil.

OBJECTIVE: This study aimed to evaluate how social distancing measures affected physical activity (PA) patterns in adults from Rio Grande do Sul, Brazil. METHODS: Participants were recruited from social and local media campaigns, contacts with private and public universities, as well as research personal contacts across the state. PA was assessed before (retrospectively) and during social distancing. Frequency (days per week) and time (minutes per day) were asked to those participants who practiced PA. Two PA variables were built to each time-frame (before and during social distancing): 1) any PA (yes/no question), and 2) sufficient PA (based on the 150 min/week cut-off point). RESULTS: Overall, 2321 participants answered the questionnaire. Any and sufficient PA decreased from before to during social distancing (22.3% and 17.0%, respectively). A linear increase of activity during social distancing was observed in participants who practiced up to 400 min or less of PA per week before social distancing. Regarding associated factors, female, overweight/obese and diagnosed chronic disease participants were less likely to practice any or sufficient PA during social distancing when compared to the period before. CONCLUSION: PA practice (both any and sufficient) decreased in Southern Brazil in the first months of social distancing. Women, overweight/obese and chronic diseased participants showed a higher decrease in PA compared to other groups. Finally, those participants who practiced PA before social distancing were more likely to continue practicing during COVID-19 pandemic.

Association between physical activity and subjective memory decline triggered by the COVID-19 pandemic: Findings from the PAMPA cohort.

Implementation of social distancing reduced the incidence of coronavirus disease (COVID-19) cases. Nevertheless, this strategy has other undesirable effects such as physical inactivity and psychological distress, which are associated with cognitive impairment. We aimed to examine whether physical activity during social distancing restrictions could reduce the risk of subjective memory decline in adults. Participants (n=2321) completed the baseline assessment of PAMPA cohort (Prospective Study About Mental and Physical Health), a ambispective cohort study conducted in southern Brazil. An online-based, self-administered questionnaire assessed physical activity and self-rated memory in two different periods: before and during social distancing. Data collection was executed from June 22nd to July 23rd 2020. Adjusted Poisson regression models were performed and values reported in prevalence ratio (PR) with 95% confidence interval (CI). Participants presented with a mean age of 38.2 (95%CI: 37.5, 38.9) years. Most were women (76.6%), had at least a university degree (66.7%), and were overweight or obese (53.3%). Subjective memory decline was reported by 30.0% (95%CI: 27.7%, 32.4%) of respondents. Most individuals with subjective memory decline reported being physically inactive during the pandemic of COVID-19. Participants were less likely to experience subjective memory decline if they either became (PR: 0.56; 95%CI: 0.36, 0.89) or remained (PR: 0.68; 95%CI: 0.49, 0.93) physically active compared to inactive respondents. Physical activity participation during social distancing reduced the likelihood of subjective memory decline in adults. Physical activity should be highlighted as a potential alternative to reduce the burden of the COVID-19 pandemic on cognitive function and mental health.

Physical Activity Measured by Accelerometry in Mozambican Older Adult Women Attending a Regular Exercise Program.

Time spent in different Physical Activity (PA) Intensities of 72 Mozambican older adult women (67 ± 7 years old) was assessed by means of triaxial accelerometers for 7 consecutive days, and participants were stratified based on their body mass index, as being normal weight (NW, n = 23); overweight (n = 16); or obese (OB, n = 33). Overall, most daily time was spent in sedentary activities (614 ± 111 min or 69.1%) and light PA (181 ± 56 min or 20.2%). On average, moderate to vigorous PA (MVPA) was performed during 10.6% of the day (93 ± 44 min). Time spent in MVPA was significantly higher in the NW compared to OB category (112.8 ± 51.5 vs. 81.0 ± 36.3; p = .021). The overweight group did not differ in time spent in MVPA when compared to NW and OB group. Overall, 75% of the participants spent more than 60 min a day in MVPA (NW: 83%; overweight: 81%; OB: 67%). Pearson's correlation between body mass index and total MVPA controlling for age was -.39 (p < .001). It was concluded that Mozambican older adult women living in urban and rural areas of Maputo province engaged in relatively high Physical Activity Intensities compared with individuals of similar ages in high-income countries, regardless of their nutritional status.

What are the challenges of epidemiological research during the COVID-19 pandemic?

Abstract The COVID-19 pandemic had an impact in several areas, and in scientific research was not different. Researchers are working from their homes since research facilities and universities were closed, and face-to-face interaction where limited to stop the virus spread. This brought a lot of changes in observational studies, especially in epidemiology research. Since most studies are being conducted through internet-based assessments, researchers are facing different challenges regarding data collection and participants recruitment, for example. In this paper, we share some of the challenges faced in a population-based study conducted in Southern Brazil, as well as possible alternatives to help researchers to overcome these issues.

Studies of Physical Activity and COVID-19 During the Pandemic: A Scoping Review.

BACKGROUND: This scoping review aimed to identify the available evidence related to physical activity (PA) and the coronavirus disease (COVID-19) pandemic. METHODS: A search in 6 databases (PubMed, Embase, SPORTDiscus, Scopus, Web of Science, and CINAHL) was conducted on July 23, 2020. Medical subject headings and keywords related to PA and COVID-19 were combined to conduct the online search, which covered the period from January to July 2020. RESULTS: Overall, 1784 articles were retrieved. After duplicate removal and title, abstract, and full-text screening, 41 articles were included. Most of the included studies were quantitative and collected data through online interviews/questionnaires, with sample sizes larger than 100 and composed by adults and older adults. Changes in PA levels due to the COVID-19 pandemic were the most assessed outcome, followed by the association between mental health issues and PA. Only 2 studies assessed the direct effects of PA on COVID-19. CONCLUSION: Most of the evidence identified a decrease in PA levels due to social distancing measures and that PA might help to decrease the mental health burden related to the COVID-19 outbreak.

Perfil dos proprietários das academias de ginástica de Pelotas-RS: um estudo censitário / Profile of the gym club owners from Pelotas-RS: a census study

O objetivo do estudo foi descrever o perfil dos proprietários de academias de gin ást icas da cidade de Pelotas-RS. Estudo descritivo parte do censo de academias de Pelotas-RSrealizado em 2 01 2. Para mapear as academias de ginástica da zona urbana da cidade, dividiu-se o município em 1 9 setores. Foram encontradas 170 academias e 183 proprietários. Os dados foram coletados através de en t revista estruturada, contendo questões econômicas (renda mensal em reais), sociodemográficas (sexo, cor da pele, idade, escolaridade), comportamentais (hábito de fumo, consumo de álcool, atividade física), labo rais (número de estabelecimentos em que é proprietário, carga horária semanal), e de conhecimento sobre legislação trabalhista (CLT) e conselho fiscalizador (CREF). Foi realizada uma análise descritiva com cálculo de médias e desvios-padrão para as variáveis numéricas e proporções para as variáveis categóricas. Ao todo, 161 proprietários participaram do estudo. Em sua maioria, os proprietários eram do sexo masculino (64,4%), de cor de pele branca (42,8%), pertencentes à faixa etária de 30 a 39 an os (4 2,8%), não fumavam (75,8%) e eram ativos fisicamente (82,0%). Quanto à formação, mais da metade (5 4,0%) era graduado em Educação Física e possuía algum curso de pós-graduação (52,2%). Com relação à experiência de trabalho em academias e conhecimento, 71,6% trabalhavam há mais de cinco ano s n as academias e 41,6% tinham pouco/nenhum conhecimento sobre leis trabalhistas. Concluiu-se que, apesar do tempo de atuação como gestores, é evidente a carência de formação adequada e conhecimento sobre legislação, indicando que os gestores ainda atuavam apenas com o conhecimento empírico adquirido ao longo dos anos...(AU)

The aim of thisstudy was to describe the profile of the gym clubs o wn ers in t he city of Pelotas-RS. This descriptive study is part of the Pelotas-RSgym club census held in 2 0 1 2 . To m ap t he gym clubs in the urban area of the city, the municipality was divided into 19 sectors. We found 1 7 0 gy m clubs and 183 owners. Data were collected through a structured interview, containing questions related t o economics (monthly income in reais), socio-demographic (sex, skin color, age, schoo lin g), beh avio ral (smoking, alcohol consumption, physical activity), labor (establishments in which it owns, weekly working hours), knowledge related to labor legislation (CLT) and supervisory board (CREF). A descriptive analysis was performed with calculation of means and standard deviations for numerical variables and proportions for categorical variables. Overall, 161 owners participated in t he st udy . The majority of the owners were male (64.4%), white skin color (42.8%), 30 to 39 years o ld (4 2.8%), n o n - smokers (75, 8%) and were physically active (82.0%). Regarding professional qualification, m ore th an half (54.0%) were graduated in Physical Education and has done some postgraduate course (52.2%). With regard to work experience in gym clubs and knowledge, 71.6% has worked in gym clubs fo r m o re t han five years and 41.6% had little or no knowledge of labor laws. It was concluded that, despite the tim e o f performance as managers, it is evident the lack of adequate training and knowledge abo ut legislat ion, indicating that the managers still only acted with the empirical knowledge acquired over the years...(AU)

Calibration of raw accelerometer data to measure physical activity: A systematic review.

Most of calibration studies based on accelerometry were developed using count-based analyses. In contrast, calibration studies based on raw acceleration signals are relatively recent and their evidences are incipient. The aim of the current study was to systematically review the literature in order to summarize methodological characteristics and results from raw data calibration studies. The review was conducted up to May 2017 using four databases: PubMed, Scopus, SPORTDiscus and Web of Science. Methodological quality of the included studies was evaluated using the Landis and Koch's guidelines. Initially, 1669 titles were identified and, after assessing titles, abstracts and full-articles, 20 studies were included. All studies were conducted in high-income countries, most of them with relatively small samples and specific population groups. Physical activity protocols were different among studies and the indirect calorimetry was the criterion measure mostly used. High mean values of sensitivity, specificity and accuracy from the intensity thresholds of cut-point-based studies were observed (93.7%, 91.9% and 95.8%, respectively). The most frequent statistical approach applied was machine learning-based modelling, in which the mean coefficient of determination was 0.70 to predict physical activity energy expenditure. Regarding the recognition of physical activity types, the mean values of accuracy for sedentary, household and locomotive activities were 82.9%, 55.4% and 89.7%, respectively. In conclusion, considering the construct of physical activity that each approach assesses, linear regression, machine-learning and cut-point-based approaches presented promising validity parameters.

Correlates of Heart Rate Measures with Incidental Physical Activity and Cardiorespiratory Fitness in Overweight Female Workers.

Previous studies have suggested that physical activity (PA) levels and cardiorespiratory fitness (CRF) impact on the autonomic control of heart rate (HR). However, previous studies evaluating PA levels did not discriminate between incidental PA and regular exercise. We hypothesized that incidental PA "per se" would influence cardiac autonomic indices as assessed via HR variability (HRV) and HR recovery (HRR) in non-exercisers. Thus, the objective of this study was to investigate the relationships between objective PA levels, CRF, and cardiac autonomic indices in adult, regular non-exercising female workers. After familiarization with procedures and evaluation of body composition, 21 women completed a submaximal cycling test and evaluation of HRR on four different days. Resting (2-min seated and standing) and ambulatory (4-h) HRV were also recorded. Levels of PA were assessed by accelerometry over five consecutive days (i.e., Wednesday to Sunday). Maximum oxygen consumption (VO2max) was measured as an index of CRF. As reliability was low to moderate for most HR measures, relationships between these and PA and CRF were examined using the 4-day average measures. Significant correlations were identified between post-exercise HRR in the first min with various PA indices (daily moderate PA, daily vigorous PA, and the sum of vigorous and very vigorous daily PA). Additionally, VO2max was significantly correlated to HRV but not to HRR. The current results indicated that CRF was influential in enhancing HRV while incidental or non-exercise based PA was associated with greater autonomic reactivation in adult overweight women. Therefore, both CRF and non-exercise based PA contribute significant but diverse effects on cardiac health. The use of 4-day averages instead of single measures for evaluation of autonomic control of HR may provide a better indication of regular cardiac autonomic function that remains to be refined.

Energy expenditure compared to physical activity measured by accelerometry and self-report in adolescents: a validation study.

BACKGROUND: Physical inactivity is responsible for 5.3 million deaths annually worldwide. To measure physical activity energy expenditure, the doubly labeled water (DLW) method is the gold standard. However, questionnaires and accelerometry are more widely used. We compared physical activity measured by accelerometer and questionnaire against total (TEE) and physical activity energy expenditure (PAEE) estimated by DLW. METHODS: TEE, PAEE (TEE minus resting energy expenditure) and body composition were measured using the DLW technique in 25 adolescents (16 girls) aged 13 years living in Pelotas, Brazil. Physical activity was assessed using the Actigraph accelerometer and by self-report. Physical activity data from accelerometry and self-report were tested against energy expenditure data derived from the DLW method. Further, tests were done to assess the ability of moderate-to-vigorous intensity physical activity (MVPA) to predict variability in TEE and to what extent adjustment for fat and fat-free mass predicted the variability in TEE. RESULTS: TEE varied from 1,265 to 4,143 kcal/day. It was positively correlated with physical activity (counts) estimated by accelerometry (rho = 0.57; p = 0.003) and with minutes per week of physical activity by questionnaire (rho = 0.41; p = 0.04). An increase of 10 minutes per day in moderate-to-vigorous intensity physical activity (MVPA) relates to an increase in TEE of 141 kcal/day. PAEE was positively correlated with accelerometry (rho = 0.64; p = 0.007), but not with minutes per week of physical activity estimated by questionnaire (rho = 0.30; p = 0.15). Physical activity by accelerometry explained 31% of the vssariability in TEE. By incorporating fat and fat-free mass in the model, we were able to explain 58% of the variability in TEE. CONCLUSION: Objectively measured physical activity significantly contributes to the explained variance in both TEE and PAEE in Brazilian youth. Independently, body composition also explains variance in TEE, and should ideally be taken into account when using accelerometry to predict energy expenditure values.

Objectively measured physical activity and body composition indices in Brazilian adolescents / Atividade física mensurada objetivamente e índices de composição corporal em adolescentes Brasileiros

The aim of the study was to explore the association between objectively measured physical activity and body composition indices in 13-year old adolescents living in country undergoing rapid nutritional transition. A population-based cross-sectional study nested within the 1993 Pelotas (Brazil) Birth Cohort was undertaken. A total of 457 boys and girls (80.5% of the target sample, 52.1% boys) participated in the study. Physical activity was measured by the Actigraph accelerometer for 5 consecutive days and expressed as total physical activity (i.e. average intensity, counts per minute) and time (min per day) spent at moderate and vigorous intensity activity. The outcomes investigated were sum of triceps and subscapular skinfolds, waist circumference, waist-to-hip ratio and waist-to-thigh ratio. After adjustment for sex, socioeconomic status, age, Tanner stage of sexual maturation, diet pattern, height, and birth weight, time (min/day) spent at vigorous intensity activity was inversely associated with waist circumference and sum of skinfolds. A one minute/day increase in vigorous intensity physical activity was associated, on average, with a reduction of 0.15cm in waist circumference (p=0.007) and 0.20mm in sum of skinfold thicknesses (p=0.02). These associations were stronger in boys than in girls. Total activity and time spent in moderate intensity physical activities were not associated with any of the outcomes in the adjusted analyses. Vigorous physical activity appears to have the strongest association with body composition. Preventive efforts aimed to decrease the obesity in adolescents may be more successful if they focus on vigorous intensity, instead of moderate intensity physical activities.

O objetivo deste estudo foi explorar a associação entre atividade física mensurada objetivamente e índices de composição corporal em adolescentes de 13 anos de idade residentes em um país sofrendo rápida transição nutricional. Um estudo transversal de base populacional aninhado a Coorte de Nascimentos de 1993 de Pelotas (Brasil) foi realizado. Um total de 457 meninos e meninas (80,5% da população alvo; 52,1% meninos) participaram do estudo. Atividade física foi mensurada pelo acelerômetro Actigraph por 5 dias consecutivos e expressa como atividade física total (intensidade média, counts por minuto) e tempo (min/dia) em atividades moderadas e vigorosas. Os desfechos investigados foram somatório de dobras triciptal e subescapular, circunferência da cintura, razão cintura-quadril e razão cintura-coxa. Após ajustes para sexo, nível econômico, idade, estágio de maturação sexual de Tanner, padrão de dieta, estatura e peso ao nascer, o tempo (min/dia) em atividades vigorosas foi inversamente associado à circunferência da cintura e somatório das dobras. O aumento de um minuto por dia no tempo em atividades vigorosas foi associado, em média, com uma redução de 0,15cm na circunferência da cintura (p=0,007) e 0,20mm no somatório das dobras (p=0,02). Estas associações foram mais fortes nos meninos comparado as meninas. Atividade física total e tempo em atividades moderadas não foram associados com nenhum dos desfechos na análise ajustada. Atividades vigorosas parecem ter a associação mais forte com composição corporal. Esforços preventivos que visem diminuir a obesidade em adolescentes podem ter mais sucesso se focarem em atividades vigorosas ao invés de atividades de intensidade moderada.

Infancy and childhood growth and physical activity in adolescence: prospective birth cohort study from Brazil.

BACKGROUND: The Developmental Origins of Health and Disease hypothesis suggests that intrauterine, infancy and early childhood variables play a key role at programming later health. However, little is known on the programming of behavioral variables, because most studies so far focused on chronic disease-related and human capital outcomes. The aim of the present study was to evaluate the effects of prenatal, infancy and childhood weight and length/height gains on objectively-measured physical activity (PA) in adolescence. METHODS: This is a prospective birth cohort study in Pelotas, Brazil, including 457 adolescents (mean age: 13.3 years) with weight and length/height data at birth, one, three and six months, one and four years of age. PA was measured using a GT1M Actigraph accelerometer, and expressed as (a) minutes per day spent on sedentary, light, moderate, vigorous and very-vigorous activities; (b) total counts per day. RESULTS: 61.3% of the adolescents accumulated 60+ minutes of moderate-to-vigorous PA per day. Weight and length/height trajectories in infancy and childhood were similar between those classified as active or inactive at 13.3 years. However, those classified as inactive were heavier and taller at all ages; differences were statistically significant only in terms of length at three, six and 12 months. CONCLUSIONS: Weight gain in infancy and childhood did not predict variability in adolescent PA, but those active in adolescence showed somewhat smaller average gains in length in infancy. These findings suggest that PA may partially be sensitive to early hormonal programming, or that genetic factors may affect both early growth and later metabolism or predisposition for PA.

Bidirectional cross-sectional and prospective associations between physical activity and body composition in adolescence: birth cohort study.

The aim of this study was to investigate the cross-sectional and prospective associations between physical activity and body composition in adolescence. This is a prospective study, including 4,103 adolescents belonging to the Pelotas (Brazil) 1993 birth cohort, who were followed up at the mean ages of 11.3 and 14.7 years. Subsample analyses included 511 individuals with accelerometry and deuterium dilution data at 13.3 years. Sum of skinfolds at age 11.3 years was highly correlated with skinfolds at age 14.7 years (rho = 0.74, P < 0.001). More than 85% of participants remained in the same quintile or changed by not more than one quintile during the 3.4 year period. Tracking of physical activity was considerably lower, although still significant; the correlation was 0.24 (P < 0.001) and 61.4% of the adolescents moved one or less quintiles. In fully-adjusted models, no significant cross-sectional or longitudinal associations were found between physical activity and body composition, neither in boys nor in girls. These null results were confirmed in the 511 individuals with accelerometry and deuterium data. We provide evidence of tracking of physical activity and particularly body composition during adolescence. Our results do not support the hypothesis that physical activity and fatness are strongly related in adolescents.