Dança Folclórica: um estudo das qualidades físicas básicas em universitários de diferentes níveis técnicos

Health and life quality can be preserved and improved by the regular practice of physical activity. Sedentarism is an undesirable condition and represents risk for the health. This study has as objective to analyze the caloric cost and the basic physical qualities in college students of different technical levels. The research was descriptive and applied to 35 students, volunteers, from 19 to 34 years old, from both sexes, participants of the Dance Body of State University of Piauí, in the city of Teresina, in the activities of folkloric dance and walking. The caloric cost was evaluated with the accelerometer Caltrac 100/100 Plan, the basic physical qualities through the sitting and reaching test (flexibility); the vertical impulsion test, crouch (inferior members strength); the abdominal test (located muscular resistance); and the Burpee test (motor coordination). The participants were separated in two groups according to their time of practice: group 1 (beginners), group 2 (advanced). The parametric tests t by Student and correlation by Pearson were used, observing a significance p<0,05 in the sense of comparing the observed results, which showed that there are no significant differences between the two groups of students, according to the time of practice, in which concerns the caloric cost. The results of Strength, Resistance and Co-ordination test did not differ so much between the two groups. On the other hand, in the variable flexibility significant differences were observed (sig.p = 0,0022 << 0,05) between the observed groups, being Group 1 (31,5 ± 6,3) meaningfully less than Group 2 (38,1 ± 4,9), which constitutes a difference of about 21%. Such results present relations of caloric cost compensation between the studied groups, the motivation to the beginners group and flexibility to tne advanced group, justifying the lack of significant distinctions. In this sense the folkloric dance, as a physical activity, appears to be efficient, for significant co-relations are still noticed between the caloric cost levels of the dance with the walking, besides not presenting expressive differences between them.

Um modelo de unidade de medida inercial utilizando três acelerômetros triaxiais

No espaço tridimensional, um corpo rígido qualquer pode efetuar translações e ou rotações em relação a cada um de seus eixos. Identificar com precisão o deslocamento realizado por um corpo é fundamental para alguns tipos de sistemas em engenharia. Em sistemas de navegação inercial tradicionais, utilizam-se acelerômetros para reconhecer a aceleração linear e giroscópios para reconhecer a velocidade angular registrada durante o deslocamento. O giroscópio, entretanto, é um dispositivo de custo mais elevado e com alto consumo de energia quando comparado a um acelerômetro. Essa desvantagem deu origem a pesquisas a respeito de sistemas e unidades de medidas inerciais que não utilizam giroscópios. A ideia de utilizar apenas acelerômetros para calcular o movimento linear e angular surgiu no início da década de 60 e vem se desenvolvendo através de modelos que variam no número de sensores, na maneira como estes são organizados e no modelo matemático que é utilizado para derivar o movimento do corpo. Esse trabalho propõe um esquema de configuração para construção de uma unidade de medida inercial que utiliza três acelerômetros triaxiais. Para identificar o deslocamento de um corpo rígido a partir deste esquema, foi utilizado um modelo matemático que utiliza apenas os nove sinais de aceleração extraídos dos três sensores. A proposta sugere que os sensores sejam montados e distribuídos em formato de L . Essa disposição permite a utilização de um único plano do sistema de coordenadas, facilitando assim a instalação e configuração destes dispositivos e possibilitando a implantação dos sensores em uma única placa de circuito integrado. Os resultados encontrados a partir das simulações iniciais demonstram a viabilidade da utilização do esquema de configuração proposto

Validação do questionário Internacional de Atividade Física (IPAQ) através da acelerometria em idosas

Physical activity is one of the main components of a healthy lifestyle, responsible for many health benefits. Despite being considered important for both disease prevention and health promotion there is high prevalence of sedentary behavior in the elderly population. Questionnaires are practical and feasible instruments for assessing levels of physical activity. However, they may have limitations in older age ranges. Accelerometers, movement sensors that make physical activity data more objective, emerge as reliable measuring devices. Aim: Determine the validity of the International Physical Activity Questionnaire (IPAQ) adapted for elderly with accelerometry in elderly women. Methods: 57 elderly women, with mean age of 66.05 ± 5.98 years who took part in hypertension control and physical activity incentive programs were assessed in relation to objective and subjective measures of physical activity. The accelerometer was used for 07 consecutive days, 24 hours per day before the IPAQ was applied. Data were analyzed using measures of central tendency and dispersion to characterize the sample according to variables collected. To check the validity of the data we used the Spearman correlation test, considering a significance level of p <0.05. Results: With respect to the categories of physical activity obtained by IPAQ, 46.4% developed moderate physical activity, followed by a high (30.3%) and low level (23.2%). There was a negative correlation only between self-reported time spent sitting and time spent on light activities as measured by accelerometry (r = - 0.408; p = 0.003) and mean activity level (counts/min) with physical activity levels evaluated by IPAQ (r = 0.297; p = 0.036). Conclusion: The IPAQ used in elderly women shows moderate to low validity levels according to accelerometry measures. Assessment of sedentary activities exhibited acceptable levels compared to accelerometry; however, moderate (r = 0.096; p > 0.05) to vigorous (r = 0.098; p > 0.05) activities were not correlated, demonstrating the inability of IPAQ to evaluate this type of activity in elderly women

Efeitos dos exercícios aeróbio contínuo e intervalado na variabilidade da frequência cardíaca em adultos jovens saudáveis. Ensaio clínico aleatório

The high-intensity interval exercise has been described as an option for increasing physical activity and its use also being suggested in the therapeutic management of many conditions such as diabetes mellitus and heart failure. However, the knowledge of its physiological effects and parameters that can assure greater safety for interval exercise prescription; especially its effect on short- and medium-term (24 hours after exercise) exercise recovery, need to be clarified. This study objective was to evaluate the effect of continuous and interval aerobic exercise on the cardiac autonomic control immediate and medium term (24 hours), by assessing heart rate variability (HRV). The present study is a randomized crossover clinical trial in which healthy young individuals with low level of physical activity had the VFC 24 hours measured by a heart rate sensor and portable accelerometer (3D eMotion HRV, Kuopio, Finland) before and after continuous aerobic exercise (60-70% HR max, 21 min.) and interval exercise (cycle 1 min. 80-90% HR max, 2 min. at 50-60% HR max, duration 21 min.). HRV was measured in the time and frequency domain and the sympathovagal balance determined by the ratio LF / HF. Nonlinear evaluation was calculated by Shannon entropy. The data demonstrated delayed heart rate recovery immediate after exercise and lower HR after 24 hours compared to pre intervention values, especially in the interval exercise group. There was a tendency to higher predominance and representatives index values of sympathetic stimulation during the day in interval exercise group; however, without statistical significance. The study results help to clarify the effects of interval exercise on the 24 hours following interval exercise, setting parameters for prescription and for further evaluation of groups with metabolic and cardiovascular diseases.

Protótipo de rastreador solar de um eixo baseado em microcontrolador

The increase in the efficiency of photo-voltaic systems has been the object of various studies the past few years. One possible way to increase the power extracted by a photovoltaic panel is the solar tracking, performing its movement in order to follow the sun’s path. One way to activate the tracking system is using an electric induction motor, which should have sufficient torque and low speed, ensuring tracking accuracy. With the use of voltage source inverters and logic devices that generate the appropriate switching is possible to obtain the torque and speed required for the system to operate. This paper proposes the implementation of a angular position sensor and a driver to be applied in solar tracker built at a Power Electronics and Renewable Energies Laboratory, located in UFRN. The speed variation of the motor is performed via a voltage source inverter whose PWM command to actuate their keys will be implemented in an FPGA (Field Programmable Gate Array) device and a TM4C microcontroller. A platform test with an AC induction machine of 1.5 CV was assembled for the comparative testing. The angular position sensor of the panel is implemented in a ATMega328 microcontroller coupled to an accelerometer, commanded by an Arduino prototyping board. The solar position is also calculated by the microcontroller from the geographic coordinates of the site where it was placed, and the local time and date obtained from an RTC (Real-Time Clock) device. A prototype of a solar tracker polar axis moved by a DC motor was assembled to certify the operation of the sensor and to check the tracking efficiency.