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The use of accelerometers to measure physical activity in epidemiological research presents challenges to increase comparability between studies that use this equipment. In this sense, the objective of this work is to compare time estimates in MVPA for adults from different data processing methods, using the Actigraph GT3X+ accelerometer. This is a cross-sectional study, from the baseline of the pilot study of the Longitudinal Study of the Determinants of Physical Activity. Sample had 31 outsourced employees of both genders, with an average age of 47.05 years (SD=9.35). Participants used GT3X+ model accelerometers for seven consecutive days. The MVPA time estimate was generated using Actilife and R-package GGIR software. Descriptive statistical analyses, ANOVA and Bonferroni post-hoc for comparability were performed in the R software. Bland-Altman analysis was performed in SigmaPlot to assess bias and agreement. There was a significant difference in the mean time of MVPA between count-based data and raw data (p<0.001). The average time in MVPA was shorter from processing by raw data than in counts (-264.81 min/day; p<0.001). Concluding that the findings suggest that there is no statistically equivalence between the methods compared to estimate MVPA time. [ABSTRACT FROM AUTHOR]

The use of accelerometers to measure physical activity in epidemiological research presents challenges to increase comparability between studies that use this equipment. In this sense, the objective of this work is to compare time estimates in MVPA for adults from different data processing methods, using the Actigraph GT3X+ accelerometer. This is a cross-sectional study, from the baseline of the pilot study of the Longitudinal Study of the Determinants of Physical Activity. Sample had 31 outsourced employees of both genders, with an average age of 47.05 years (SD=9.35). Participants used GT3X+ model accelerometers for seven consecutive days. The MVPA time estimate was generated using Actilife and R-package GGIR software. Descriptive statistical analyses, ANOVA and Bonferroni post-hoc for comparability were performed in the R software. Bland-Altman analysis was performed in SigmaPlot to assess bias and agreement. There was a significant difference in the mean time of MVPA between count-based data and raw data (p<0.001). The average time in MVPA was shorter from processing by raw data than in counts (-264.81 min/day; p<0.001). Concluding that the findings suggest that there is no statistically equivalence between the methods compared to estimate MVPA time. [ABSTRACT FROM AUTHOR]

This work investigated the feasibility of using the BBC micro: bit internal accelerometer in experimental activities. Two experiments were used for tests, which dealt with Newton's Second Law and the Rotation motion. In both, the objective was to directly evaluate the acceleration and thus analyze the data through descriptive statistics and graphical analysis, generating results that will serve as a reference for students in the laboratory, in addition to clarifying concepts of visualization and comprehension. The results obtained help to better understand what really happens in acceleration movements and can help to reorganize experimental activities for the teaching of Physics. [ABSTRACT FROM AUTHOR]

The shoulder bag is the most widely used implement for transporting school supplies. About 25% of school children complain of musculoskeletal pain, often associated with excessive weight of school backpacks (Ries et al., 2012). Poor backpacking habits persist throughout the school years and, consequently, lead to chronic musculoskeletal problems, which may worsen into adulthood (Jardim, 2013). Although these symptoms are associated with other factors, it is assumed that these may be related to the weight overload, in which these children are systematically exposed. For this reason, a petition was submitted to the Assembly of the Republic in Portugal, where it was suggested that definitive legislation should be adopted to ensure that children's backpacks should not exceed 10% of their body weight and that schools should regulate weekly the minimum school activities. The theory of dynamic systems assumes that motor behavior is a consequence of a network of codependent systems (e.g., musculoskeletal, nervous, respiratory, etc.), from which motor patterns emerge through processes of self-organization (Glazier et al., 2003; Kelso, 1995; Williams et al., 1999). The objective of this study is to verify if the children show postural readjustment (parameter of order) when constrained to the backpack with different weights (control parameter). The sample consisted of sixteen children aged between 8 and 9 years of the first cycle of basic education. Each child carried out a 5-meter course with a backpack, under the following conditions: i) without added weight; ii) with 3kg added; and (iii) with 5 kg added. The three-dimensional acceleration values were recorded in g units, collected through the Physics Toolbox Suite (Vyera Software) application installed on a ZTE smartphone. The data were filtered and smoothed in each of the components of the three-dimensional axis in MatLab software (The MathWorks, Inc), through a High-Pass filter. The Friedman test (χr2) was used to compare the conditions, followed by the Wilcoxon (T) test, with Bonferroni correction. No significant changes were observed in the vertical (χr2 = 1.625, ns) and anteroposterior (χr2 = 0.375, ns) components. However, for the mediolateral component, there was a significant difference between conditions (χr2 = 15.500, p0.001); attributable to a significant reduction of the acceleration of the condition without additional load to that with addition of 3kg (T = -2.741, p≤0.01), and the condition with no additional load for the with addition of 5kg (T = -3.206, p≤0.001). Since the backpack is attached to the trunk and has a series of degrees of freedom allowed by the spine, we deduce that children seek a more stable motor solution when subjected to additional weight, probably by reducing degrees of freedom. In this case, the process of dimensional compression must be considered as a constraint (Santos et al., 2015). [ABSTRACT FROM AUTHOR]

The introductory textbooks on classical mechanics are extremely brief in addressing impulsive forces and the concept of impulse. This can be explained by the emphasis on the study of physical situations in which the applied forces are all constant or position dependent, but constant in time, which is the class of the so-called conservative forces. When the impulsive forces are referred to, they are generally illustrated by a quick blow on a ball, as in golf, tennis or baseball. The focus is still to turn the time dependent force into a constant average force, whose impulse is equivalent to the real force. This paper proposes a simple experiment that consists in applying with the fingers an impulsive force on a smartphone and record the time dependence of the force through its internal accelerometer. This technology allows obtaining the values of the speed during the applied impulsive force by iterating the data extracted of acceleration and time. Some interesting aspects neglected in books emerge from this analysis, such as the lack of symmetry of the applied impulsive force, the possibility of modeling the full interaction without appeal to the concept of average force and calculating impulse directly by impulse and linear momentum theorem. As a consequence of the experiment, it is also possible to obtain the kinetic friction coefficient between the smartphone and the horizontal surface. [ABSTRACT FROM AUTHOR]

We present the basic properties of an electronic accelerometer and some possibilities for its use in Mechanics teaching practices proposals for an experimental Physics lab. An accelerometer when tightly coupled to a body, allows the direct reading of the set acceleration. From the acceleration it is possible to obtain information on various physical quantities of the kinematics and dynamics, such as velocity, acceleration and force. We present the physical and operational characteristics of the accelerometer and the electronic circuit for measuring and processing the electrical signal obtained as the output device. We present results of measurements performed on two practices on the issues "Bungee Jump" and differential acceleration of the bar rotational motion. Such practices can be reproduced in a laboratory of experimental Physics. We believe that the use of the device in question shows to be promise for use in numerous other practices in Physics teaching, it is aimed at teaching important innovation in the laboratory, the possibility of using the feature of Real-Time Physics with a class demonstration and in the point of view of involving students in interdisciplinary projects. [ABSTRACT FROM AUTHOR]

Nowadays, there is a large growth in need to control remote applications using technology to control wireless communication, allowing greater mobility to the controller. Faced with such requirements, it was thought to develop an application that allows a virtual joystick creation capable of controlling some applications through a mobile device. It was studies the data manipulation from the accelerometer, the sending of such data and how to send data to the Windows OS. To make this possible, it is necessary that this device has accelerometer and Bluetooth technologies. The project goal is to control computer applications using a virtual joystick that will receive data from sensors of movements and buttons present in the mobile device. It will possible to control all applications that have support for joystick as games, simulators and navigation softwares. [ABSTRACT FROM AUTHOR]