abstract: It is broadly accepted that physical activity provides substantial health benefits. Despite strong evidence, approximately 60% to 95% of US adults are insufficiently active to obtain these health benefits. This dissertation explored five projects that examined the measurement properties and methodology for a variety of physical activity assessment methods. Project one identified validity evidence for the new MyWellness Key accelerometer in sixteen adults. The MyWellness Key demonstrated acceptable validity evidence when compared to a criterion accelerometer during graded treadmill walking and in free-living settings. This supports the use of the MyWellness Key accelerometer to measure physical activity. Project two evaluated validity (study 1) and test-retest reliability evidence (study 2) of the Global Physical Activity Questionnaire (GPAQ) in a two part study. The GPAQ was compared to direct and indirect criterion measures including object and subjective physical activity instruments. These data provided preliminary validity and reliability evidence for the GPAQ that support its use to assess physical activity. Project three investigated the optimal h.d-1 of accelerometer wear time needed to assess daily physical activity. Using a semi-simulation approach, data from 124 participants were used to compare 10-13 h.d-1 to the criterion 14 h.d-1. This study suggested that a minimum accelerometer wear time of 13 h.d-1 is needed to provide a valid measure of daily physical activity. Project four evaluated validity and reliability evidence of a novel method (Movement and Activity in Physical Space [MAPS] score) that combines accelerometer and GPS data to assess person-environment interactions. Seventy-five healthy adults wore an accelerometer and GPS receiver for three days to provide MAPS scores. This study provided evidence for use of a MAPS score for future research and clinical use. Project five used accelerometer data from 1,000 participants from the 2005-2006 National Health and Nutrition Examination Study. A semi-simulation approach was used to assess the effect of accelerometer wear time (10-14 h.d-1) on physical activity data. These data showed wearing for 12 h.d-1 or less may underestimate time spent in various intensities of physical activity. / Dissertation/Thesis / Ph.D. Physical Activity, Nutrition and Wellness 2011

I ABSTRACT Title: Kinesiological analysis of upper limb punch strike in sports karate. Aim of work: The aim of this thesis to describe and characterize the muscle involement in direct punch strike in karate. Then compared with the exercises, which are characteristic to karate - strikes with resistence and push-up exercise. Methods: Work is processed by a comparative analysis of selected movements based on the determination of muscle activation. The surface electromyography method synchronized with video and accelerometer was used in this work. Results: The result is describtion of selcted movements on the basis of muscle activation and function of selected muscles. The prove that the forearm extensors are activated as the last of the selcted muscles was managed. On the basis of karate technique and anatomy we confirmed important role of forearm extensor by direct punch in karate. The difference between onset time muscle activation by strikes and push up was found. Maximum speed of acral part of the upper limb by direct punch was established. Keywords: Electromyography (EMG), karate, direct punch - gyakucuki, accelrometer

Background: Studies have reported that preschool children may not be sufficiently active according to guidelines. This is worrying because early childhood is a critical period for the establishment of sedentary behaviour (SB) and physical activity (PA) habits, which have immediate and long term influences on health. The majority of evidence on levels, determinants, and health consequences of SB and PA in young children is, however, based on subjective measures in predominately White children aged three years or older. Aims: To 1) assess the feasibility and acceptability of using three different accelerometers in South Asian and White British 2-3 year olds and their parents; 2) calibrate and validate the accelerometers to measure SB and PA in 2-3 year olds; 3) investigate the influence of 5-, 10-, and 15-second epochs on time spent in SB, light PA, and moderate-to-vigorous PA (MVPA) in 2-3 year olds; and 4) assess the feasibility of measuring the habitual SB and PA with the ActiGraph GT3X+ accelerometer in South Asian and White British 2-3 year olds and their parents. Methods: Focus groups were performed with 17 South Asian and White British mothers and the audio-recordings were transcribed verbatim and analysed with thematic analysis (Aim 1). To calibrate the three accelerometers against direct observation (Aim 2), semi-structured activity sessions were run with 18 South Asian and White British 2-3 year olds. Mixed-effects regression and receiver-operating characteristics (ROC) curve analysis were used to generate prediction equations and 5- and 10-second cut-points to assess children s SB and PA. Validity of the generated cut-points against direct observation (Aim 2) was assessed in a separate sample of 20 White British and Black African 2-3 year olds during free-play, using Cohen s kappa, ROC curve analysis, Bland-Altman plots, and Lin s concordance coefficient. Differences in estimated time spent in SB, light PA and MVPA from 5-, 10- and 15-second epochs were tested with repeated-measures ANOVA and paired t-tests in the calibration sample (Aim 3). A pilot study was conducted with 120 South Asian and White British families from a birth cohort study to address aim 4. Study intake and compliance with an 8-day measurement protocol were calculated, and differences between ethnicities were assessed with the Chi-square test. Results: The ActiGraph GT3X+ was the most widely accepted accelerometer, with the least amount of issues raised by mothers. Practical and software issues with the Actiheart and activPAL3 during the calibration phase resulted in insufficient good quality data collected, which made it unfeasible to calibrate both monitors. The overall 5-second Axis1 cut-points for the ActiGraph GT3X+ provided a valid tool to measure the SB and total PA of 2-3 year olds in free-living conditions. Using 10- and 15-second epochs overestimated children s light PA and underestimated time spent in SB and MVPA. Less South Asian than White British families were recruited into the study, and less South Asian than White British children complied with the 8-day measurement protocol. There were no ethnic differences in the number of children and parents providing enough accelerometry data (i.e. ≥ 3 valid days), or the number of parents complying with the measurement protocol. Conclusions: The results demonstrated that it is feasible to use the ActiGraph GT3X+ to assess the habitual SB and PA of a bi-ethnic sample of 2-3 year old children and their parents. The accurate assessment of SB and PA in 2-3 year olds using the overall 5-second Axis1 cut-points developed and validated in this thesis will enable researchers to investigate the levels, determinants, and health consequences of SB and PA. Such research will inform public health policies and interventions to improve children s health.

abstract: The instrumentational measurement of seismic motion is important for a wide range of research fields and applications, such as seismology, geology, physics, civil engineering and harsh environment exploration. This report presents series approaches to develop Micro-Electro-Mechanical System (MEMS) enhanced inertial motion sensors including accelerometers, seismometers and inclinometers based on Molecular Electronic Transducers (MET) techniques. Seismometers based on MET technology are attractive for planetary applications due to their high sensitivity, low noise floor, small size, absence of fragile mechanical moving parts and independence on the direction of sensitivity axis. By using MEMS techniques, a micro MET seismometer is developed with inter-electrode spacing close to 5 μm. The employment of MEMS improves the sensitivity of fabricated device to above 2500 V/(m/s2) under operating bias of 300 mV and input velocity of 8.4μm/s from 0.08Hz to 80Hz. The lowered hydrodynamic resistance by increasing the number of channels improves the self-noise to -135 dB equivalent to 18nG/√Hz (G=9.8m/s2) around 1.2 Hz. Inspired by the advantages of combining MET and MEMS technologies on the development of seismometer, a feasibility study of development of a low frequency accelerometer utilizing MET technology with post-CMOS-compatible fabrication processes is performed. In the fabricated accelerometer, the complicated fabrication of mass-spring system in solid-state MEMS accelerometer is replaced with a much simpler post-CMOS-compatible process containing only deposition of a four-electrode MET structure on a planar substrate, and a liquid inertia mass of an electrolyte droplet. With a specific design of 3D printing based package and replace water based iodide solution by room temperature ionic liquid based electrolyte, the sensitivity relative to the ground motion can reach 103.69V/g, with the resolution of 5.25μG/√Hz at 1Hz. By combining MET techniques and Zn-Cu electrochemical cell (Galvanic cell), this letter demonstrates a passive motion sensor powered by self-electrochemistry energy, named “Battery Accelerometer”. The experimental results indicated the peak sensitivity of battery accelerometer at its resonant frequency 18Hz is 10.4V/G with the resolution of 1.71μG without power consumption. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2016

Epilepsy is a disability with a large research field but yet with little knowledge and understanding about finding a cure. The common idea as to why an epileptic seizure is triggered is because of over activity in the neurons of the brain. More than 60 000 people in Sweden suffer from epilepsy. Damages from an epileptic seizure can be life threatening if left uncontrolled and a solution is needed in order to detect and alarm if a seizure has appeared. This project refers to building a system that can detect a seizure and locate the position of the patient having the seizure. This system also creates the possibility for a contact person to take part of the information. As there were no persons with the diagnose epilepsy at hand, the project group decided that simulated seizures were necessary. Development of the system has been categorised into three subsystems. The subsystems are a bracelet unit, a mobile application and a cloud-service. The projects subsystems were developed and the system was completed. A bracelet unit was created. This bracelet is able to detect if an epileptic seizure has occurred. A Bluetooth low energy connection between the bracelet and the mobile application was enabled making it possible for an alarm to be sent to a contact person during a seizure.

Orientador: Fabiano Fruett / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-14T00:04:04Z (GMT). No. of bitstreams: 1 Nicolau_Murilo_M.pdf: 4612178 bytes, checksum: 32c4dc903e6f634bd499ceae5ef338ee (MD5) Previous issue date: 2009 / Resumo: O Brasil é um dos maiores produtores mundiais de frutas e hortaliças. No entanto as perdas de produtos hortículas, devido a danos físicos e estresse térmico, são estimadas em cerca de 30%a 40%, podendo chegar a 50 % para certos produtos. As perdas pós-colheita de hortícolas tem início na sua colheita e pode culminar em seu descarte antes mesmo deste chegar ao consumidor final. O conhecimento das variáveis geradoras deste desperdício, suas influências e inter-relações pode colaborar para minimizar o problema. Apresentamos neste trabalho um instrumento capaz de monitorar os impactos e a temperatura durante a colheita e pós-colheita. Este instrumento, denominado Fruta Eletrônica, foi projetado para ser uma ferramenta acessível ao produtor rural. A esfera instrumentada mede e armazena impactos tri-axiais na faixa de 0,5g até 250g e temperatura na faixa de 0° C até 80º C. Testes em campo realizados em uma linha de beneficiamento de laranjas na cidade de Eng. Coelho, SP, mostram que esse instrumento pode fornecer informações úteis que colaboram na identificação dos pontos de estresse mecânico e térmico, os quais os frutos são submetidos. / Abstract: Brazil is one of the largest worldwide producers of fruit and vegetables. However, the loss of horticultural products due to physical damage and thermal stress is estimated at about 30 % to 40 %, even 50 % for certain products. The process that degrades the quality of vegetables starts during its harvest and can culminate in its disposal even before reaching the final consumer. The knowledge of the variables that act in this waste generating process, their influences and inter-relationships can help to minimize the problem. In this work, we present a tool capable of monitoring the impacts and temperature during the postharvest. This instrument, called Fruta Eletrônica, was designed to be an accessible tool for the farmers. This instrument measures and stores triaxial impacts from 0.5 g to 250 g and temperatures between 0 °C and 80 °C. Field tests, carried out in an orange packing line treatment in Eng. Coelho city, show that this instrument can provide useful information to assist identifying the points of mechanical and thermal stress in which fruits are submitted. / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Orientadores: Antonio Augusto Fasolo Quevedo, Waldir Antonio Bizzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-14T20:06:15Z (GMT). No. of bitstreams: 1 Ramos_AndredePaula_M.pdf: 3634888 bytes, checksum: 6ac215157ad6cab344d793b24a2bc1cd (MD5) Previous issue date: 2009 / Resumo: O espirômetro é um dispositivo que avalia a ventilação pulmonar. Este é um trabalho preliminar que propõe um sensor eletromecânico de fluxo com foco na aplicação biomédica de espirometria. O sensor consiste de um corpo rombudo, introduzido em um cano por um orifício, e um acelerômetro. A colisão das partículas do fluido contra o corpo rombudo gera vórtices, que por sua vez induzem vibrações no corpo. Forças de arrasto também estão presentes e tendem a movimentar o corpo. Os movimentos decorrentes do escoamento são captados pelo acelerômetro, que é posicionado na porção do corpo rombudo externa ao cano, evitando o contato do elemento eletrônico (acelerômetro) com o fluido, o que pode facilitar procedimentos de esterilização da luz do cano. Foram analisados corpos rombudos em forma de lâmina (com e sem massa adicional) e cilindro. O procedimento experimental consistiu no estabelecimento de seis regimes permanentes de entrada (vazão de ar) e na captura do sinal de resposta do sensor (nos três eixos). Foram coletadas 24 respostas do sensor para cada um dos regimes e posteriormente foram levantadas as curvas do sensor e realizadas análises estatísticas. Resultados significativos foram encontrados para o eixo do acelerômetro paralelo ao fluxo. Para a lâmina, o Valor Eficaz (RMS) do sinal foi proporcional à vazão com linearidade e coeficiente de correlação variando, respectivamente, de 19% e R2 = 0,99058, para o ensaio sem massa adicional, a até 8,4% e R2 = 0,9741, para o ensaio com massa adicional. O arrasto contínuo (valor médio da resposta) não guardou relação monotônica com o aumento da velocidade do ar. Já para o cilindro, o arrasto foi proporcional à vazão com altíssima linearidade e correlação (0,17% e R2 = 0,96347), mas o RMS do sinal não guardou relação monotônica com a vazão. Finalmente, embora sejam necessários mais estudos para utilizar o sensor proposto em equipamentos de espirometria, este trabalho demonstra que o sensor responde proporcionalmente às entradas (escoamento), dentro (de 0 a até 14 l/s) e fora da faixa (até 21 l/s) de operação do espirômetro com altos coeficientes de correlação e linearidade, além de respostas diferenciadas dadas diferentes entradas (vazões) comprovadas por ANOVA (valor de p < 10-15). / Abstract Spirometer is a device that evaluates pulmonary ventilation. This paper presents a preliminary study of a new electromechanical sensor, focused on the biomedical application of spirometry. The sensor is composed of a bluff body positioned inside a tube trough a hole, being a part of the body inside and another part outside of the tube, and an accelerometer positioned on the outside part. Within a fluid flow, the bluff body causes vortex shedding, and the vortexes induce vibrations on the body. Also, the viscous force of the flow drags the bluff body. Both movements are captured by the accelerometer and correlated with the flow. One important feature of this sensor is that the fluid does not contact any of the electronics, easing tube lumen sterilization procedures. Three types of bluff bodies were studied: two blades (with and without additional mass), and one cylinder. The experimental procedure consisted of establishing six different air flows and then capturing the accelerometer response in all of its three axes. Each of the collected signals from the accelerometer was divided in 24 parts, and these parts where analyzed through statistics; finally the mean response of the sensor was plotted. Best results were found in the accelerometer axis parallel to the air flow. In the blade tests, the RMS value of the AC component was proportional to the air flow, with linearity and correlation varying, respectively, from 19% and R2 = 0.99058 for the blade without mass, to 8.4% and R2 = 0.9741 for the blade with additional mass. It was observed that the mass addition reduced in a meaningful way the response variances. Yet the viscous force (DC value) did not respond in a monotonic way with the increase of air flow. On the other hand, the viscous force was the most expressive regarding the experiments with the cylinder (linearity of 0.17% and R2 = 0.96347), but the RMS value did not respond in a monotonic way. Finally, although further studies are needed to prove that the proposed sensor is efficient to be used in spirometry equipment, this study demonstrates that this sensor responds proportionally to the flow input, within (0 to 14 l/s) and without (up to 21 l/s) the spirometer operation range, with high correlation and linearity, as well as varying responses, given different inputs (flow), as verified by ANOVA test (p < 10-15). / Mestrado / Engenharia Biomedica / Mestre em Engenharia Elétrica

A massagem tradicional tem sido auxiliada com o uso de acessórios convencionais e eletro-eletrônicos, onde estes produtos trabalham por intermédio de equipamentos programados por micro-controladores que atuam de forma eficiente, atuando na qualidade de vida do ser humano. O objetivo principal deste trabalho foi comparar os níveis de freqüência (Hz) da almofada vibratória com os da esteira vibratória tendo como referência a massagem tradicional e a vibroterapia, analisando por meio de pesquisa quantitativa o desenvolvimento e fabricação de aparelhos vibratórios. Não é do nosso conhecimento estudos avaliando tais parâmetros nesta área, pois a comparação e detalhamento de freqüências tem o parecer inédito neste aspecto. Foram feitos dez medições de freqüências com uso de tacômetro e acelerômetro para as quatro funções na almofada vibratória e, cinco medições para as quinze funções na esteira vibratória onde os valores de intensidades mínimo e máximo foram comparados às normas para garantir o bem estar no momento da utilização. Para os aparelhos vibratórios utilizados nesse trabalho, foram encontrados valores de freqüências de 7,33 a 116,35 Hz, onde na massagem tradicional a variação é de 10 a 20 Hz, para as normas de fabricação é de 1 a 100 Hz para corpo inteiro, 5 a 1.250 Hz para as transmitidas à mão e 100 a 300 Hz citados em trabalhos acadêmicos. Portanto, ambos os aparelhos vibratórios apresentaram resultados de valores de freqüência dentro dos limites definidos pelos autores de trabalhos acadêmicos, assim como as normas de fabricação. / The traditional massage has been assisted with use of conventional accessories and electric-electronics, where this product works for intermediary of equipment programmed by microcontrollers that act of efficient form acting in the quality of life of the human being. The mean goal of this study was to compare the levels of frequency (Hz) vibration of the pad with the belt vibration with reference to traditional massage and vibrotherapy, analyzing by quantitative research development and manufacturing of vibration equipments. Not the best of our knowledge studies evaluating these parameters in this area, because the comparison of frequencies and detail has unpublished opinion in this regard. Ten measurements were made of frequencies using tachometer and accelerometer for the four functions in vibrating cushion and, five measurements for the fifteen functions in vibrating mat where the values of minimum and maximum of intensities were compared to standards to ensure the well-being at use. For the vibration equipments used in this study, we found values of frequencies from 7,33 to 116,35 Hz, where the change in traditional massage is 10 to 20 Hz, for the standards of manufacture is from 1 to 100 Hz for the whole body , 5 to 1.250 Hz vibration to the hands and 100 Hz to 300 cited in academic work. Therefore, both devices performed vibration frequency of values within the limits defined by the authors of academic works and the manufacture standards.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-18T12:35:08Z No. of bitstreams: 1 edimarpedrosagomes.pdf: 940108 bytes, checksum: 884d94d7277860ef98661b0483d9d892 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-18T12:50:06Z (GMT) No. of bitstreams: 1 edimarpedrosagomes.pdf: 940108 bytes, checksum: 884d94d7277860ef98661b0483d9d892 (MD5) / Made available in DSpace on 2017-05-18T12:50:06Z (GMT). No. of bitstreams: 1 edimarpedrosagomes.pdf: 940108 bytes, checksum: 884d94d7277860ef98661b0483d9d892 (MD5) Previous issue date: 2013-08-02 / Introdução: Inatividade física é a quarta principal causa de morte em todo o mundo, principalmente devido à sua associação com as doenças cardiovasculares, que são particularmente importantes nos pacientes em hemodiálise. Objetivos: Este estudo investigou a atividade física na vida diária de pacientes em hemodiálise, usando um acelerômetro triaxial e avaliou as variáveis fisiológicas associadas à inatividade. Métodos: 19 pacientes em hemodiálise (47,5+12,5 anos) foram avaliados e comparados com 19 controles sedentários (45,9+13,3 anos), em relação ao tempo gasto em diferentes atividades ou posições (andando, de pé, sentado ou deitado) e ao número de passos dados. Resultados: Os pacientes em hemodiálise apresentaram menor tempo ativo (soma dos períodos andando e de pé) por dia do que o grupo controle (193,0+54,0 vs. 272,0+78,8 minutos/dia; p=0,001), com menor tempo de caminhada (70,1+27,3 vs. 100,7+32,6 minutos/dia; p=0,003) e menor tempo em pé (122,8+40,4 vs. 171,2+65,3 minutos/dia; p=0,009). Os pacientes em hemodiálise também permaneceram mais tempo deitados do que os controles (201,1+93,2 vs. 46,6+68,8 minutos/dia; p<0,001). De acordo com o número de passos dados por dia, 47,4% dos pacientes em hemodiálise foram considerados sedentários, contra 10,5% no grupo controle. Pacientes em hemodiálise permaneceram mais sedentários nos dias com diálise. O nível de hemoglobina correlacionou com o tempo gasto caminhando (r=0,53, p=0,003). Conclusões: Os pacientes em hemodiálise são menos ativos que os indivíduos sem doença renal crônica, principalmente nos dias com diálise. Entre as variáveis estudadas, apenas a hemoglobina correlacionou-se com a inatividade física. / Introduction: Physical inactivity is the fourth leading cause of death worldwide, mainly by its association with cardiovascular diseases, especially in hemodialysis patients. This study investigated the physical activity in daily life in hemodialysis patients, by using a triaxial accelerometer and evaluated the physiological variables associated with inactivity. A total of 19 hemodialysis patients (47.5 + 12.5 years) were evaluated and compared with 19 control individuals (45.9 + 13.3 years), regarding the time spent in different activities and positions of daily life (walking, standing, sitting and lying), and the number of steps taken. Results: The hemodialysis patients demonstrated a shorter activity time (walking plus standing time) per day than control subjects (193.0 + 54.0 vs. 272.0 + 78.8 min/day; p=0.001), with shorter walking (70.1 + 27.3 vs. 100.7 + 32.6 min/day; p=0.003) and standing time (122.8 + 40.4 vs. 171.2 + 65.3 min/day; p=0.009). Hemodialysis patients spent more time lying down per day than control subjects (201.1 + 93.2 vs. 46.6 + 68.8 min/day; p<0.001). According the number of steps taken per day, 47.4% of hemodialysis patients were classified as sedentary against 10.5% in control group. Hemodialysis patients were more sedentary on dialysis days than on non-dialysis days. The hemoglobin level correlated with the walking time (r=0.53, p=0.003). Conclusions: Hemodialysis patients are less active than individuals without chronic kidney disease, especially on dialysis days. Among the variables studied, only hemoglobin correlated with physical inactivity.

Made available in DSpace on 2014-08-20T13:49:17Z (GMT). No. of bitstreams: 1 Marina Kremer.pdf: 2292543 bytes, checksum: 3a2779d82461fca54a905419fba65fb2 (MD5) Previous issue date: 2010-02-26 / The school, and in particular the Physical Education classes (PE), are in a privileged position for the promotion of health among children and adolescents. However, little is known about the PE programs in Brazil. The aim of this study was to estimate the intensity and duration of physical efforts in PE classes in primary and secondary school. Methodology: A school-based cross-sectional study was carried out. A multistage sampling strategy was used, including stratification by education network (public and private) and grade. We sampled 16 schools, and 272 students took part in the study, totaling 218 classes observations. We administered a questionnaire to identify physical spaces and materials available to the PE classes and a questionnaire for students. The outcome variables were evaluated by an instrument of direct observation the System for Observing Fitness Instruction Time SOFIT; and the intensity of the classes was measured by accelerometry. To determine the intensity of the efforts we used the following cut-off points (in counts): sedentary activities (0-100), light activities (101-2000), moderate activities (2001-4999), vigorous (5000-7999) and very vigorous (>8000). The outcome "moderate to vigorous physical activity (MVPA)" was created by grouping moderate, vigorous and very vigorous activities. Results: The mean duration of the classes was 35.6 minutes (SD 6.0), whereas the mean time spent in MVPA was 12.3 minutes (SD 9.7). The mean proportion of the time spent on MVPA was 32.7% (SD 25.2). Boys (44.1%) spent a higher proportion of the classes in MVPA as compared to girls (21.0%; p<0.01). Students who practice physical activity outside the PE classes were more likely to engage in MVPA during the classes. There were no significant differences in the practice of MVPA in different educational networks and school grades. Conclusions: The proportion of time spent in MVPA was low, indicating that during PE classes students are, most of the time, carrying out activities that are not of sufficient intensity and duration to produce organic changes leading to health benefits. Urgent strategies are needed in order to increase the intensity and duration of physical efforts in Physical Education classes / A escola, em especial as aulas de Educação Física (EF) encontram-se em posição privilegiada para promoção da saúde entre crianças e adolescentes. Entretanto, pouco se conhece sobre os programas de EF no Brasil. O objetivo do estudo foi determinar a intensidade e duração dos esforços físicos nas aulas de EF no ensino fundamental e médio. Metodologia: Foi desenvolvido um estudo transversal de base escolar. A amostragem foi realizada em múltiplos estágios, estratificada por rede, nível e série de ensino. Ao todo, 16 escolas e 272 estudantes participaram do estudo, totalizando 218 observações de aula. Foi aplicado um questionário para identificar espaços físicos e materiais disponíveis para a aula de EF e um questionário para os estudantes. As aulas foram avaliadas através do instrumento de observação direta SOFIT (System for Observing Fitness Instruction Time) e a intensidade mensurada através de acelerômetros. Para a determinação da intensidade dos esforços foram adotados os seguintes pontos de corte (em counts): atividades sedentárias (0-100), leves (101-2000), moderadas (2001-4999), vigorosas (5000-7999) e muito vigorosas (>8000). Para determinação do desfecho atividades físicas moderadas a vigorosas (AFMV) foram agrupadas as categorias de AF moderada, vigorosa e muito vigorosa. Resultados: O tempo médio de duração das aulas foi de 35,6 minutos (DP 6,0), enquanto que a média de tempo das aulas despendido efetivamente em AFMV foi de 12,3 minutos (DP 9,7). A proporção média de tempo das aulas em AFMV foi de 32, 7% (DP 25,2). Os meninos (44,1%) envolveram-se significativamente mais em AFMV do que as meninas (21,0%; p<0,01). Estudantes que se envolvem em atividade física fora das aulas também tiveram maior participação em AFMV nas aulas de EF. Não foram encontradas diferenças significativas na prática de AFMV em diferentes redes de ensino e série escolar. Conclusão: A proporção de tempo em AFMV encontrada foi baixa indicando que durante as aulas de EF os estudantes são pouco submetidos a atividades com intensidades e duração suficientes para provocar adaptações orgânicas que tragam benefício à saúde. Estratégias urgentes são necessárias para o aumento da intensidade e duração dos esforços físicos em aulas de Educação Física.