Activity of periscapular muscles and its correlation with external oblique during push-up: Does scapular dyskinesis change the electromyographic response?

Scapular dyskinesis is the term used to describe changes in the positioning or movement of the scapula. Such dysfunction is associated with changes in the activation of the scapular muscles. However, the influence of the axial muscles on the scapular muscles activity of subjects with scapular dyskinesis is unknown. This study aimed to compare the electromyography (EMG) activity of periscapular muscles and its correlation with the external oblique muscle during the execution of push-up performed in different surfaces, in volunteers with and without scapular dyskinesis. Thirty-six men, divided in two groups (control and dyskinesis), performed push-up on stable and unstable surface. The EMG activity of serratus anterior (SA_5th and SA_7th fibers), upper (UT) and lower (LT) trapezius, external oblique (EO) was recorded during execution of each task condition. Statistical analyzes were performed using two way ANOVA repeated measures and Pearson correlation. It was observed effect of interaction between factors, being evidenced increased activity of UT, SA_7th and OE for the control group and decreased activity of SA_5th, SA_7th and EO for dyskinesis group during execution of push-up on unstable surface. In both groups positive correlations (r > 0.47) were observed between EMG activity of SA and EO. In the exercises tested, there seems to be an anatomical and functional relationship between the SA and EO muscles. The use of the unstable surface promotes increased neuromuscular demand, but the neuromuscular strategies appear to differ between groups.     

Effects of weightlifting exercise,traditional resistance and plyometric training on countermovement jump performance: a meta-analysis

Jump performance is considered an important factor in many sports. Thus, strategies such as weightlifting (WL) exercises, traditional resistance training (TRT) and plyometric training (PT) are effective at improving jump performance. However, it is not entirely clear which of these strategies can enable greater improvements on jump height. Thus, the purpose of the meta-analysis was to compare the improvements on countermovement jump (CMJ) performance between training methods which focus on WL exercises, TRT, and PT. Seven studies were included, of which one study performed both comparison. Therefore, four studies comparing WL exercises vs. TRT (total n = 78) and four studies comparing WL exercises vs. PT (total n = 76). The results showed greater improvements on CMJ performance for WL exercises compared to TRT (ES_diff: 0.72 ± 0.23; _95%CI: 0.26, 1.19; P = 0.002; Δ % = 7.5 and 2.1, respectively). The comparison between WL exercises vs. PT revealed no significant difference between protocols (ES_diff: 0.15 ± 0.23; _95%CI: ?0.30, 0.60; P = 0.518; Δ % = 8.8 and 8.1, respectively). In conclusion, WL exercises are superior to promote positive changes on CMJ performance compared to TRT; however, WL exercises and PT are equally effective at improving CMJ performance.     

Exploring the perspectives of physically active and inactive adolescents: how does physical education influence their lifestyles?

Based on a socio-ecological framework for physical education (PE), this study explored and analysed the perspectives of physically active and inactive adolescent boys and girls with different socioeconomic status (SES), regarding the meanings that PE had on their physical activity (PA) lifestyles throughout childhood and adolescence. An interpretative and qualitative design was adopted and operationalised through an individual two-hours in-depth interview. Thematic analysis identified five main themes that distinguish active from inactive adolescents: ‘Early experiences of PE at primary school’; ‘PE experiences in middle and secondary school’; ‘Friendly, professional and pedagogue. That’s what I want from my PE teacher’; ‘Friends in PE and PA’; ‘Active lifestyles? Are schools and PE ready for making a difference?…’. Regardless of the lifestyle, girls revealed more PE negative experiences, related to uninteresting and competitive activities, groups’ constitution and logistic factors. SES played a major role on their PA and PE experiences, with low SES adolescents having limited opportunities inclusively within the primary school PE context. This study provides evidence for the importance of promoting positive PE and PA experiences in early years. Based on adolescents’ voices, several recommendations are discussed that can be considered for improving PE professionals’ effectiveness in promoting active lifestyles.     

Effect of wetted surface area on friction,pressure, wave and total drag of a kayak

Using theoretical principles, the components of drag (friction D _F, pressure D _PR and wave D _W) of a single-seat kayak were analysed. The purpose was to examine the effect of changes in wetted surface area due to changes in kayaker’s weight and the relative contribution of D _F, D _PR and D _W to the total passive drag as function of velocity. The total passive drag values were based on experimental data collected in a single-seat kayak. Three different kayaker simulated weights were tested – 65, 75 and 85 kg. D _F was the drag component that contributed the greatest percentage (between 60 and 68% at 5.56 m/s the top velocity tested) to the total passive drag for all the velocities tested and simulated weights. D _W was the most affected by the increase in kayaker’s simulated weight, mainly when comparing 65/75 to 85 kg. Results support the importance of a kayak design selection that minimises the kayak’s drag for the individual weight of the kayaker. Also, the results suggest that the path for better hydrodynamic kayak performance should seek changes that can reduce D _F, D _PR and D _W with D _F offering the most potential to reduce passive drag.     

Sodium bicarbonate ingestion increases glycolytic contribution and improves performance during simulated taekwondo combat

Purpose: To investigate the effect of sodium bicarbonate (NaHCO₃) on performance and estimated energy system contribution during simulated taekwondo combat. Methods: Nine taekwondo athletes completed two experimental sessions separated by at least 48?h. Athletes consumed 300?mg/kg body mass of NaHCO₃ or placebo (CaCO₃) 90?min before the combat simulation (three rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration [La^?] and rating of perceived exertion (RPE) were measured before and after each round, whereas heart rate (HR) and the estimated contribution of the oxidative (W_OXI), ATP (adenosine triphosphate)-phosphocreatine (PCr) (W_PCR), and glycolytic (W_{[ La^? ]}) systems were calculated during the combat simulation. Results: [La^?] increased significantly after NaHCO₃ ingestion, when compared with the placebo condition (+14%, P?=?0.04, d?=?3.70). NaHCO₃ ingestion resulted in greater estimated glycolytic energy contribution in the first round when compared with the placebo condition (+31%, P?=?0.01, d?=?3.48). Total attack time was significantly greater after NaHCO₃ when compared with placebo (+13%, P?=?0.05, d?=?1.15). W_OXI, W_PCR, VO₂, HR and RPE were not different between conditions (P?>?0.05). Conclusion: NaHCO₃ ingestion was able to increase the contribution of glycolytic metabolism and, therefore, improve performance during simulated taekwondo combat.     

Ignoring taboos: Maria Lenk, Latin American inspirationalist

Maria Lenk is widely recognized as an exceptional athlete who participated in women's sport from around 1930 until 1950. In 1932, at the age of seventeen, she was the first woman to be included in a Latin American delegation to the Olympic Games. As a swimmer, she still sets world records at the age of eighty-six. This super-champion's sporting achievements and her persistent dedication to the advancement of sport still impress and surprise todays professional swimmers and researchers. Contextualised in the male-dominated society of Brazil during the first half of the twentieth century, this chapter traces the achievement, and rise to international fame, of Maria Lenk. It examines the factors that enabled her to emerge not only as an important figure in sport but also as an icon of female emancipation in Brazilian and Latin American society. The focus is on Lenk's influence on the issues which affected the development of women's sport in Latin America. It also highlights the significance of Lenk's contribution to the changing place of women in Brazilian and South American society.     

Contingent Valuation and Semiparametric Methods: A Case Study of the National Museum of Sculpture in Valladolid, Spain

Research on cultural economics is very interested in the economic valuation of non-market goods, particularly in the field ofcultural heritage where contingent valuation techniques are currently being used with both parametric and non-parametric statistical methods to estimate the willingness to pay for cultural goods. In the literature analysed, the number of studies using semiparametric methods, however, is very limited. Our analysis is intended to help fill this gap by offering a parametric, non-parametric and semiparametric economic valuation of the National Museum of Sculpture (Museo Nacional de Escultura), located in Valladolid,Spain. In addition, we also gain insight on a controversial issue affecting most European museums, particularly those located in Latin countries: the role voluntary donations might play in the funding of public museums.     

PROBLEMS OF EQUIVALENCE OF STUDIES AND DIPLOMAS IN HIGHER EDUCATION SYSTEMS

This article Surveys the problems and the traps of equivalences in higher education and proposes solutions to the former and ways of avoiding the latter. To begin with, one must be clear as to basic concepts and be able to distinguish between recognition and equivalence, the second being synonymous with the first, if formal equivalence is what is meant. But the principal task is one of defining and granting so‐called real equivalence, that is, equivalence based on the comparison of educational programmes, contents, length of study, the methods and the results of evaluations, and appropriate assessments of the academic value of practical work. It is also necessary to be clear at the outset as to the purposes of a given equivalence: to permit further study in another country or to aid in securing employment in a given occupation in another country. A major problem relates to varying conceptions of what is specifically university education in relation to higher education as a whole; the weight to be granted to post‐secondary, non‐university training; the whole question of length of studies; and ambiguities relative to terminology. Although it will never be possible to formulate ideal solutions to all problems, the key to obtaining the best possible solution is to be found in the improvement of the availability of standardized information by the exploitation of such sources as Unesco statistics, student books, analyses of bilateral conventions for applicable analogies, and, eventually, the sort of diploma supplement which Carin Berg and Ulrich Teichler are recommending.