Effects of school aerobic exercise intervention on children’s health-related physical fitness : a portuguese middle school case study

This dissertation study was primarily designed to (a) determine the current healthrelated physical fitness and health-enhancing physical activity of Portuguese middle school children and (b) determine the effects on Portuguese middle school children’s health-related physical fitness of a one-school-year aerobic exercises intervention in school physical education. 264 middle school children; aged 10 to 15 years were selected from four public middle schools in the Minho region of Portugal. All subjects completed six health-related physical fitness tests in FITNESSGRAM, including the One mile run, curl-up, push-up, trunk left, sit-and-reach, and skinfolds test. The body mass index (BMI) was included to measure children’s body composition. The International Physical Activity Questionnaire (IPAQ) was selected and translated into Portuguese to estimated children’s physical activity levels (especially for moderate to vigorous physical activity - MVPA). The heart rate monitor was also used to measure children’s physical activity levels in their different school physical education classes. 141 children aged from 10 to 15 years in one middle school (Minho region, Braga), were selected from the sample 264 children to participate in a one-school-year (exclude the two-month summer vacation and holidays) aerobic exercise intervention in their school physical education classes. We randomly selected 2 classes from the 6th, 7th and 9th grade levels. We then divided them into control and experimental groups. The control groups (70 children; 31 male, 39 female) participated their normal, twice-weekly physical education classes; the experimental groups (71 children; 31 male, 40 female) participated in a one-school-year physical education intervention that added health-enhancing physical activity (aerobic exercises), nutrition and diet information, and some cognitive-behaviour strategies to the normal physical education program. The 141 subjects took all the tests before and after the intervention so as to compare the difference in their health-related physical fitness testing between the same groups and between the two different groups, according to the different age groups and genders. The results revealed that 82.6% of the children failed to meet all minimum standards in FITNESSGRAM that define what it means to be physically fit. More than 20% of the children were overweight and about 7% of the children suffered from obesity (the latter measurement completed by comparing individual BMI with the standard of international Obesity Task Force. Results also show that more than half of the children are not physical active, girls are less active than boys (r=-0.36, p<0.001). 19.2% of the study’s sample do not participate in any physical activity outside school and girls exercise less outside school than do boys (g: 27.6%: b: 10.3%). This study also shows that children who regularly participate in moderate-to-vigorous physical activity has a moderate correlation with children’s health-related physical fitness (rall=0.30, p<0.01; rboy=0.26, p<0.05; rgirl=0.31, p<0.05) and cardiovascular fitness (rall=0.41, p<0.01; rboy=0.27, p<0.01; rgirl=0.30, p<0.05). According to the heart rate monitoring in 28 7th grade children in different indoor physical education classes, we found that children have little opportunity to exercise aerobically during their school physical education classes. On average, subjects spent 27.9 minutes (42.6% of actual class time or 31.0% of schedule class time) in moderate-to-vigorous physical activity with their heart rate above 139 bpm in the 90-minutes indoor physical education classes, subjects spent 14.4 minutes (49.8% of actual class time or 32.0% of schedule class time) in moderate to vigorous physical activity with their heart rate above 139 bpm in the 45-minutes indoor classes. Our study shows that traditional school physical education is not effective to promote children health and children in school physical education classes spend large amounts of class time being inactive and we also found that a lot of time has been spent on changing clothes and taking shower. While the intervention did not significantly improve children’s health-related physical fitness testing in all components, it did produce some improvement in their health-related physical fitness. For example, the children in the experimental groups showed greater improvement in health-related physical fitness tests and more children in experimental groups reached the level of physically fit in FITNESSGRAM. We also found the children in experimental groups improved in some components, such as aerobic capacity abdominal and upper body strength and endurance. The elder girls in experimental groups, who had a two hours extracurricular aerobic training as a school team, significantly improved in many health-related physical fitness items. In conclusion, the school-based aerobic exercise intervention combined by some health education was identified practicable and successfully. While a one school year intervention and only in school physical education did not result in significant improvement in all components of physical fitness. Our intervention indicates that aerobic exericse can and should be adopted as a regular component of school physical education programs. Active school physical education, active leisure, and school environments that encourage good health and active lifestyle can contribute to the development of life-long healthy lifestyle in children.Este estudo tem como principais objectivos determinar a condição física relacionada com a saúde dos estudantes portugueses do 2º e 3º ciclos do ensino básico e determinar os efeitos de uma intervenção com exercícios aeróbicos na escola, durante a aula de educação física, ao longo de um ano lectivo. Foram seleccionadas 264 crianças de quatro escolas públicas EB 2,3 entre os 10 e os 15 anos na região do Minho. Todos os sujeitos realizaram os seis testes da bateria de FITNESSGRAM: corrida de uma milha, abdominais, extensões de braços, extensão do tronco, senta e alcança e medição das pregas adiposas. O índice de massa corporal foi incluído para medir a composição corporal das crianças. O Questionário Internacional de Actividade Física (IPAQ) foi traduzido para português e aplicado para avaliar os níveis de actividade física (principalmente de moderada a intensa - MVPA). O monitor da frequência cardíaca foi usado para medir os níveis de actividade física das crianças nas aulas de educação física. 141 crianças entre os 10 e os 15 anos foram seleccionadas numa das escolas, da amostra de 264 crianças, para participarem numa intervenção com exercícios aeróbicos durante as aulas de educação física na escola ao longo do ano lectivo. Seleccionámos aleatoriamente duas turmas de 6º, 7º e 9º anos e separámo-las em grupo de controlo e grupo experimental. Os grupos de controlo (70 crianças: 31 rapazes, 39 raparigas) participaram normalmente nas aulas de educação física duas vezes por semana; os grupos experimentais (71 crianças; 31 rapazes, 40 raparigas) participaram numa intervenção que acrescentou ao programa normal de educação física: actividade física para melhorar a saúde (exercícios aeróbicos), nutrição, informação sobre dieta e algumas estratégias cognitivas e de comportamento. Os 141 sujeitos realizaram todos os testes antes e depois da intervenção para compararmos as diferenças da sua condição física relacionada com a saúde entre os mesmos grupos (antes e depois) e entre o grupo experimental e o de controlo, de acordo com os vários grupos de idade e géneros. Os resultados revelaram que 82.6% das crianças não conseguiram atingir os resultados mínimos no FITNESSGRAM que definem uma boa condição física. Mais de 20% das crianças são gordas e aproximadamente 7% das crianças sofrem de obesidade (comparando o índice de massa corporal individual com os padrões do Grupo de Trabalho Internacional sobre a Obesidade). Os resultados também mostram que mais de metade das crianças não são fisicamente activas, as raparigas são menos activas que os rapazes (r=- 0.36, p<0.001). 19.2% da amostra não participam em qualquer actividade física fora da escola e as raparigas fazem menos exercício fora da escola do que os rapazes (raparigas: 27.6%; rapazes: 10.3%). Este estudo também mostra que existe uma correlação moderada entre a participação regular em actividade física moderada a intensa e a condição física relacionada com a saúde (r todos=0.30, p<0.01; r rapazes=0.26, p<0.05; r raparigas=0.31, p<0.05) e a condição cardiovascular (r todos=0.41, p<0.01; r rapazes=0.27, p<0.01; r raparigas=0.30, p<0.05). De acordo com a monitorização da frequência cardíaca de 28 crianças do 7º ano em diferentes aulas de educação física no ginásio verificámos que as crianças têm pouca oportunidade de realizar exercício aeróbico nas aulas de educação física escolar. Nas aulas de educação física de 90 minutos, os alunos realizaram em média 27.9 minutos (42.6% de tempo real de aula ou 31.0% de tempo de aula de acordo com o horário) de actividade física moderada a intensa, com a frequência cardíaca acima de 139 pulsações/minuto. Nas aulas de 45 minutos, os alunos realizaram 14.4 minutos (49.8% de tempo real de aula ou 32.0% de tempo de aula de acordo com o horário) de actividade física moderada a intensa com uma frequência cardíaca acima de 139 pulsações/minuto. O nosso estudo mostra que a educação física escolar tradicional têm muito tempo de reduzida actividade durante as aulas de educação física escolar e passam muito tempo nos balneários. Apesar de a intervenção não ter melhorado significativamente a condição física das crianças relacionada com a saúde em todos os seus componentes, houve algumas melhorias. Por exemplo, as crianças dos grupos experimentais mostraram melhorias superiores nos testes de condição física relacionada com a saúde e houve mais crianças nos grupos experimentais a atingirem os níveis de boa condição física no FITNESSGRAM. Também verificámos que as crianças dos grupos experimentais melhoraram em algumas componentes, tal como capacidade aeróbica, a força abdominal, força dos membros superiores e endurance. As raparigas dos escalões etários mais elevados dos grupos experimentais, que tiveram duas horas de treino aeróbico extracurricular, melhoraram significativamente em muitos itens da condição física relacionada com a saúde. Em conclusão, a intervenção com exercícios aeróbicos na escola combinados com alguma educação para a saúde, foi considerada realizável e bem sucedida, enquanto uma intervenção apenas em educação física escolar não resultou em melhoria significativa dos diversos testes de condição física. A nossa intervenção indica que o exercício aeróbico pode e deve ser adoptado como uma componente regular dos programas de educação física escolar. A educação física escolar aeróbica, o lazer activo e os ambientes escolares que potenciem a actividade física podem contribuir para o desenvolvimento de estilos de vida activos e saudáveis das crianças.Fundação para a Ciência e a Tecnologia

The Acceleration/Deceleration Control Algorithm Based on Trapezoid-Curve Jerk in CNC Machining

Abstract: In this study, we put forward an Acc/Dec control algorithm based on trapezoid-curve jerk in order to avoid step change in jerk curve. Moreover, the motion profile smooth control approach based on continuous jerk is developed in details to decrease machine tools impact according to various kinematics constraint conditions, such as the maximum acceleration, the maximum jerk, the machining program segment displacement, the instruction feed rate and so on; Finally, the developed Acc/Dec approach and the traditional linear Acc/Dec approach are compared in the CNC experimental table. The results reveal that the developed approach can achieve more smooth and flexible motion profile, which is helpful to minish machine tools impact and enhance parts machining surface quality

Survival of esophageal cancer in China: A pooled analysis on hospital-based studies from 2000 to 2018

Background: Esophageal cancer (EC) causes more than 400 thousand deaths per year, and half of them occur in China. There are discrepancies regarding the survival of EC patients between population-based surveillance studies and hospital-based studies. Objectives: We aimed to synthesize the survival data from hospital-based EC studies in the Chinese population from 2000 to 2018 and to compare the survival rates between EC patients with different clinical classifications. Methods: The protocol of this systematic review was registered in PROSPERO (CRD-42019121559). We searched Embase, PubMed, CNKI, and Wanfang databases for studies published between January 1, 2000 and December 31, 2018. We calculated the pooled survival rates and 95% confidence intervals (CIs) by Stata software (V14.0). Results: Our literature search identified 933 studies, of which 331 studies with 79,777 EC patients met the inclusion criteria and were included in meta-analyses. The pooled survival rates were 74.1% (95% CI: 72.6–75.7%) for 1-year survival, 49.0% (95% CI: 44.2–53.8%) for 2-years survival, 46.0% (95% CI: 42.6–49.5%) for 3-years survival, and 40.1% (95% CI: 33.7–46.4%) for 5-years survival. An increased tendency toward EC survival was verified from 2000 to 2018. In addition, discrepancies were observed between EC patients with different clinical classifications (e.g., stages, histologic types, and cancer sites). Conclusions: Our findings showed a higher survival rate in hospital-based studies than population-based surveillance studies. Although this hospital-based study is subject to potential representability and publication bias, it offers insight into the prognosis of patients with EC in China

Control spiral wave dynamics using feedback signals from line detectors

We numerically study trajectories of spiral-wave-cores in excitable systems modulated proportionally to the integral of the activity on the straight line, several or dozens of equi-spaced measuring points on the straight line, the double-line and the contour-line. We show the single-line feedback results in the drift of core center along a straight line being parallel to the detector. An interesting finding is that the drift location in $y$ is a piecewise linear-increasing function of both the feedback line location and time delay. Similar trajectory occurs when replacing the feedback line with several or dozens of equi-spaced measuring points on the straight line. This allows to move the spiral core to the desired location along a chosen direction by measuring several or dozens of points. Under the double-line feedback, the shape of the tip trajectory representing the competition between the first and second feedback lines is determined by the distance of two lines. Various drift attractors in spiral wave controlled by square-shaped contour-line feedback are also investigated. A brief explanation is presented.Comment: 6 pages and 7 figures; Accepted for publication in EPL; Figs.5 and 6 are in JPG forma

Simultaneous measurement of displacement and temperature based on two cascaded balloon-like bent fibre structures

A low-cost optical fibre sensor based on two cascaded balloon-like bent fibre (BBF) structures for simultaneous displacement and temperature measurement is reported. The sensor is fabricated by cascading two balloon-like bent single-mode fibres (SMFs) which with different bending radii, generating two separate interference dips within a limited wavelength range. The wavelength of the two interference dips exhibits different responses to external displacement and temperature variations, hence simultaneous measurement of displacement and temperature is realized. Experimental results show that the proposed optical fibre sensor achieves a displacement sensitivity of −318.8 pm/μm and a temperature sensitivity of 47.4 pm/°C. Taking advantage of its low-cost, ease of fabrication, and experimentally determined high sensitivity, the sensor in this investigation can be potentially applied in both displacement and temperature measurement fields

Application of Nano-Crystalline Diamond in Tribology

Nano-crystalline diamond has been extensively researched and applied in the fields of tribology, optics, quantum information and biomedicine. In virtue of its hardness, the highest in natural materials, diamond outperforms the other materials in terms of wear resistance. Compared to traditional single-crystalline and poly-crystalline diamonds, nano-crystalline diamond consists of disordered grains and thus possesses good toughness and self-sharpening. These merits render nano-crystalline diamonds to have great potential in tribology. Moreover, the re-nucleation of nanocrystalline diamond during preparation is beneficial to decreasing surface roughness due to its ultrafine grain size. Nano-crystalline diamond coatings can have a friction coefficient as low as single-crystal diamonds. This article briefly introduces the approaches to preparing nano-crystalline diamond materials and summarizes their applications in the field of tribology. Firstly, nano-crystalline diamond powders can be used as additives in both oil- and water-based lubricants to significantly enhance their anti-wear property. Nano-crystalline diamond coatings can also act as self-lubricating films when they are deposited on different substrates, exhibiting excellent performance in friction reduction and wear resistance. In addition, the research works related to the tribological applications of nano-crystalline diamond composites have also been reviewed in this paper