Quanto tempo é necessário para recuperar de uma tarefa exaustiva/inabitual?

O exercício físico exaustivo e inabitual, como ocorre tipicamente em diversas modalidades desportivas, induz alterações estruturais, ultra-estruturais e bioquímicas de carácter focalizado e reversível

Synchronism in electoral cycles : how united are the United States?

The role of national, sectional, state, and local forces in driving electoral outcomes in the United States has remained a matter of considerable indeterminacy in the American politics literature. In what concerns House elections, different approaches and methods have yielded widely divergent results. In what concerns presidential elections, considerable doubts remain about the timing and the plausible causes of a long-term trend towards homogeneity. In this paper, we take a new look at the nationalization of politics in the United States. We are particularly interested in the dynamic nationalization in presidential elections, i.e., the extent to which swings and shifts from one election to the next have been similar across states and whether or not that similarity has increased through time. We treat this problem as one of similarity or dissimilarity — and convergence or divergence of — electoral cycles, and use wavelets analysis in order to ascertain the degree to which the national and state election cycles have been synchronized and the degree to which that synchronization has increased or decreased. We determine, first, the states where electoral change has been more in sync with the national cycle and clusters of states defined in terms of the mutual synchronization of their own electoral cycles. Second, we analyze how the degree of synchronization of electoral cycles in the states has changed through time, answering questions as to when, to what extent, and where has the tendency towards a “universality of political trends” in presidential elections been more strongly felt. We present evidence strongly in favor of an increase in the dynamic nationalization of presidential elections taking place in the 1950s, showing that alternative interpretations concerning the historical turning point in this respect are not supported by empirical evidence.Fundação para a Ciência e a Tecnologia (FCT

Stress Analysis on a “L” shape Truss Optimization

The metal construction market in Brazil has grown significantly over the past few years. The weight reductions and performance increase of mechanical pieces obtained by using optimization techniques are significant to the point that currently its use is critical to define that competitiveness of the metal-mechanical engineering industries, and its undeniable importance in reducing costs. The optimization applied in the mechanical part design consists of using computational methods for dimensions, shape or optimal topology of parts. This study aims to propose a study methodology to analyse the stress distribution thought the use of mathematical software and photoelasticity techniques, to propose a new structural profile, lighter and more efficient, which may be used as solution to overcome the current constructive limitations

Comparison of muscle morphology, electromyographic activity and force production between prepubertal boys and girls

The purpose of this research was to compare the maximal voluntary isometric force (MVIF), the electromyographic activity (EMG) and the muscle thickness between pre-pubertal boys and girls. The sample comprises 27children (12 boys and 15 girls) with 9.5W.52 years old. The M V F and the EMG signal were acquired when the subjects made a single exercise of arm curl and triceps press. To evaluate the MVIF was used a dynamometer (TSD121C from Biopac Systems Znc.). During the arm curl exercise, one surface electrode (TSD 150A from Biopac Systems Znc.) was attached in each biceps. During the triceps press, one surface electrode was attached to the vastus lateralis and other to the vastus medialis of the each triceps. Ground electrode was attached to the elbow. The EMG signals were amplified by a differential amplifier with 2MW, a gain of 1000 and a bandwidth between 15-450Hz. The EMG signals were full-wave rectified and smoothed, allowing to determinate the integral of the EMG signal (iEMG). The iEMG was relativized according to the duration of the contraction. The muscle thickness of the biceps and of the triceps of both arms were measured by B-mode ultrasonography, using real-time electronic scanner with 7.5MHz scanning head (Ecocamera Aloca SSD-500). For comparison of those variables between gender was used the ANOVA factorial and Scheffe as post-hoc test (p< 0.05). There was no significant differences on the MVIF between boys and girls doing the arm curl exercise F(1; 25)=4.128, p=0.0529] or the triceps press exercise F(1; 25)=0.003, p=0.9554]. In the same way, there were no significant differences according to gender on the thickness of the triceps of the left arm F(1; 25)= 0.075, p=0.7859] of the triceps of the right arm F(1;25)=0.925, p=0.3454] of the bicep sof the left arm F(1;25)=0.257, p=0.6166] and of the biceps of the right arm F(1; 25)= 0.016, p=0.8989]. The EMG parameters also didn't present significant differences according to gender for the vastus lateralis of both arms, for the vastus medialis of both arms and for the biceps of the right and of the left arm. Therefore, we might conclude that apparently there are no significant differences on the muscle morphology, electromyographic activity and force production between pre-pubertal boys and girls.info:eu-repo/semantics/publishedVersio

Habitual physical activity pattern of prepubescent boys and girls

The propose of this study is to identify the pattern physical activity of boys and girls during a week. The sample comprises 14 girls and 11 boys of 9.5 years of age. Physical activity was evaluated thought the computer science and applications (CSA - 7164) activity monitor, during 4 days - two-week days (Monday and Friday), and during the weekend (Saturday and Sunday). The activity monitor was worn in wrist of the non-dominant arm. After de data collection it was calculated the mean of activity per min in each day. The repeatedmeasuresMANOVAwasusedtoanalysedthechangesbetweenday's activity,and the gender differences. The results indicated a significant main effects of days, meaning that the pattern of activity change over days. The differences occurred between the Friday and Saturday, and between Saturday and Sunday. In the weekend it was registered less physical activity than in weekdays in booth boys and girls. There's no significant main effect for gender, meaning that the physical activity of boys and girls are similar. Also there's no interaction between gender and days, meaning that the changes in activity pattern was similar for booth boys and girls.info:eu-repo/semantics/publishedVersio

Electrocardiographic findings in pregnant women in Angola

Background: Studies on the electrocardiogram findings in African pregnant women are limited. There is no information available in the literature on the electrocardiographic parameters of pregnant Angolan women. Objectives: The aim of this study was to describe electrocardiographic findings in women with normal pregnancies in Bengo Province, Angola. Methods: This is a community-based study with a cross-sectional design conducted between September 2013 and March 2014 in Bengo. The study involved 114 black pregnant women, compared with a paired control group comprising of 120 black non-pregnant women, aged 15 to 42 years. A 12-lead electrocardiogram and a rhythm strip were recorded for all participants. Results: In this study, the mean age was 26.2 ± 7.3 years. Comparing pregnant women vs. non-pregnant, we found the following mean values: Heart rate (83 bpm vs. 74 bpm, p <.001), PR interval (146 ms vs. 151 ms, p =.034), QT interval (360 ms vs. 378 ms, p <.001), QTIc Fridericia (398 ms vs. 403, p =.017), QTIc Framingham (399 ms vs. 404 ms, p =.013) and T-wave axis (340 vs. 410, p =.001).The main electrocardiographic changes found were: Sinus tachycardia (4.4% vs. 2.5%), T-wave inversion (14.9% vs. 1.7%), Minor ST segment depression (4.5% vs. 0%) and left ventricular hypertrophy (11.4% vs. 11.7%, p =.726). Conclusions: Pregnant Angolan women compared with controls, had several significantly higher values for heart rate, and significantly lower values of systolic blood pressure and diastolic blood pressure, PR interval, QT interval, QTc interval by Fridericia and Framingham and T-wave axis. Sinus tachycardia, T-wave inversion, and left ventricular hypertrophy, were the main electrocardiographic changes found. © 2022 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.The present study was supported by Camões, Institute of Cooperation and Language, Portugal; Calouste Gulbenkian Foundation, Portugal; Government of Bengo Province, Angola; and the Angolan Ministry of Healt

Strength training effects on pre-pubertal boys

There are some incongruent results in strength training effects on pre-pubertal boys. Vrijens (1979) shows that prepubescent boys were incapable of increasing strength or muscle cross-sectional area of the extremities following a program of resistance training. Various recent studies have shown that prepubescent boys are capable of making strength gains following an appropriate training program (Ramsay, et al., 1990). However the mechanisms underling strength gains following resistance strength training programs is not well clarified. There is some evidence that the gains are associated with neuromuscular adaptations with no muscle hypertrophy, but this later issue is an unresolved question. The purpose of this study is to investigate the resistance strength training effects on pre-pubertal boys, that is, the enhancement of strength and its correlates, namely the changes in muscular mass and neuro-muscular activity. The sample comprises 11 boys, aged 9,52±0,55 years, divided in an experimental group (EG) (n=6) and in a control group (CG) (n=5). All boys were in stage 1 according to Tanner’s scale of sexual maturation. The sample was evaluated in serum testosterone level, and all boys were above the level of 50 ng*dl-1,wich is considered to be within the normal range for pre-pubertal boys (Winter, 1978). The EG group was submitted to a training program with callisthenic exercises three sessions a week for 10 weeks. In each session the training comprised the following exercises: push-ups, modified pull-ups and the 2 exercises with elastics (elbows flexion and extension and extension of the arms above the head) until exhaustion. The training volume was being gradually adapted from 3 series between the 1st and 3rd week to 4 series between the 4th and 6th week and to 5 series between the 7th and 10th week. The sample was evaluated in pre and in post-test in maximal isometric voluntary force (MIVF), muscle mass, and in EMG. The MIVF was evaluated during the Shoulder Press (SP), the Arm Curl (AC) and the Triceps Press (TP). The MIVF was measured using a dynamometer (TST 121C from Biopac Systems Inc.). We also evaluated the maximal number of push ups (PU) and modified pull ups (MPU), and the distance in over arm throw with roller-skate hockey ball (THW). The EMG signals were acquired during the MIVF exercises (SP, AC, and TP). During the AC exercise, one surface electrode (TSD 150A from Biopac Systems Inc.) was attached to each biceps. During the SP and TP, one surface electrode was attached to the vastus medialis of each of the triceps. A ground electrode was attached to the elbow. The EMG signals were amplified through a differential amplifier with 2MW, a gain of 1000 and a bandwidth between 15-450Hz. The EMG signals were full-wave rectified and smoothed, allowing to determinate the integral (iEMG) and the amplitude (aEMG) of the EMG signal. The iEMG was standardised according to the duration of the contraction. Both aEMG and iEMG results of both arm in each exercise were summed. The muscle thickness of the biceps and of the triceps of both arms were measured by B-mode ultrasonography, using real-time electronic scanner with 7.5MHz scanning head (Ecocamera Aloca SSD-500). The data were analysed using the ANOVA repeated measures (group x training program). In THW the results indicate a significant interaction effect (F(1, 9) = 7,814; p = 0,021), with an increase of 22% in EG and a slight decrease in CG. In PU the results indicate a significant main effect (F(1, 9) = 15,537; p = 0,003), and a significant interaction effect (F(1, 9) = 16,61; p = 0,003), with an increase of 150% in EG and no changes in CG. In MPU the results indicate a significant main effect (F(1, ) = 8,006; p = 0,019), and a significant interaction effect (F(1, 9) = 17,667; p = 0,002), with an increase of 120,9% in EG and a slight decrease in CG. There were no significant changes in the three tests of MIVF and in iEMG, aEMG, or in the muscle mass. These results indicate that pre-pubertal boys could increase the resistance strength after a training program that include callisthenic exercises, but seems that the isometric strength could not be enhanced. The increase in resistance strength is not accompanied by an increase in muscle mass. Although in this study we only evaluated the neuro-muscular factors in MIVF, it seems that the factors underlying the enhanced strength might be neuro-muscular.info:eu-repo/semantics/publishedVersio

Effects of a 10 weeks training programs on prepubescent girls

The purpose of this study was to investigate effects of a training program on the development of the maximal isometric strengths, the push-ups, the pull-ups and the throw of the roller-skate hockey ball. The sample was composed by 16 girls, at the age of 9,5 years and in the maturation stage I according to Tanner's Scale. The sample was divided into two different groups, the experimental one (EG, n = 11) and the control one (CG, n = 5). The EG group was submit- ted to a training program with callisthenic exercises three times a week (90 min each session) during 10 weeks. The program comprised the training of push-ups, modified pull-ups and the 2 exercises with elastics (elbows flexion and extension and extension of the arms above the head) until exhaustion. The training volume has been gradually adapted from 3 series between the 1st and 3rd week to 4 series between the 4th and 6th week and to 5 series between 7th and 10th week. The maximal isometric voluntary force (MIVF) was evaluated during the Shoulder Press (SHPRES) exercise, the Arm Curl (ARMCURL) exercise and de Triceps Press (TRIPES) exercise. The MIVF was measured using a dynamometer (TST 121C from Biopac Systems Inc.). We also evaluated the maximal number of push ups and modified pull ups that each girl could do. Finally, we measured the distance made by the roller-skate hockey ball after being thrown (THRW). For the comparison between the two measurements (before and after the training program) was raised the "Paired Simple Test" in each group (p < 0.05). It compared the minimum values between the two moments on the e.g., the THRW (p = 0.006), the PULL (p=0.010), and the PUSH (p= 0.014), presented significant increases. However, the TRIPES (p = 0.096), the ARMCURL (p = 0.403), and the SHPRES (p = 0.066) didn't present significant differences. On the CG the only significant difference was found in the TRIPES (p = 0.003).info:eu-repo/semantics/publishedVersio