Effects of plyometric training on maximal-intensity exercise and endurance in male and female soccer players

In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35–1.76), throwing (ES = 0.62–0.78), sprint (ES = 0.86–1.44), change of direction speed (ES = 0.46–0.85) and endurance performance (ES = 0.42–0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.     

An analysis of the sources of earnings variation among Brazilian males

The paper uses data from the 1980 Brazilian census to analyse the sources of earnings variation among males with emphasis on the role of education, labor market segmentation, geographic location and sector of economic activity. The results indicate a sizeable private rate of return to investment in education across labor market “segments”, especially among rural workers and the self-employed. Such a finding is upheld after econometric corrections for dependent variable (earnings) truncation and selectivity bias regarding who enters a particular economic sector. However, regional earnings differentials persist even after adjustment for a set of personal and job characteristics. Thus, internal migration still has a role to play towards reducing regional earnings disparities.     

Lifelong learning policies shaping the life courses of young adults. An interpretative analysis of orientations,objectives and solutions

ABSTRACT

In the following article, we share our findings from the comparative analyses of 54 lifelong learning policy measures implemented in nine European countries, with a particular focus on their orientations, objectives, and solutions devised. Informed by the theoretical framework of Interpretive Policy Analysis (IPA), we have further reasoned on the impacts and unintended effects on young adults’ life course transitions, especially those in vulnerable positions, as well as on the hidden ambivalences and incompatibilities in the objectives and orientations of lifelong learning policies. The article provides, first, a brief discussion of the conceptual and methodological choices made. Second, it gives an overview of the design and data basis of our research. In the third section, we present and discuss the central findings from our interpretive analyses, and we finally conclude with a discussion on current trends in lifelong learning policymaking and on their impact on young adults’ transitions.     

Body composition and nutritional profile of male adolescent tennis players

Abstract

In this cross-sectional study, we evaluated the body composition and dietary intake of 44 adolescent tennis players. After being divided into two groups (age 10–13 years and age 14–18), the players had their weight, height, and sexual maturation assessed. Dual-energy X-ray absorptiometry was used to assess body composition. Food intake was obtained from a non-consecutive 4-day food record. The data were analysed using the Virtual Nutri v.1.0 software and compared with the present recommendations for adolescent athletes or dietary reference intakes. Body mass index and body fat for tennis practice were adequate for 89% and 71% of the tennis players respectively, regardless of age group. A calorie deficit greater than 10% of energy expenditure was observed in 32% of the sample. Fifty percent of the athletes consumed carbohydrates in accordance with recommended values. Protein and lipid intakes were above recommended values, while fibre, calcium, potassium, magnesium, and folic acid intakes were below recommendation for 98%, 80%, 100%, 100%, and 98% of the tennis players respectively. The observed nutritional deficiencies represent an additional barrier for adolescents engaged in competitive sports to achieve an optimum nutrition to maintain growth, health, and performance.     

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

Abstract

This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18?33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s^?1 (60° · s^?1) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80?150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.     

Overcompliance and reluctance to make decisions: Exploring warning systems in support of public managers

Post-scandal effects in public management point to the occurrence of overcompliance in the work of public managers, leading to reluctance and paralysis in decision-making. This article discusses the proposition of an artifact in the form of a warning system to aid the analysis process and issuing of opinions (APIO) by public managers, providing more information and, consequently, less risk and fear. The Design Science Research method was used to exapt a scientific artifact to the context of public management. The textual structure of 178 opinions issued by public agencies was analyzed, as was the perception of 17 public managers of the characteristics of the APIO. Exaptating the artifact from a technological perspective is simple and feasible, as it involves processes with strong functional similarities. The greatest challenges to operationalize the artifact broadly and without restrictions, as occurs in scientific academia, are associated with informational behaviors.     

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18-33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s(-1) (60° · s(-1)) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80-150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.     

Effects of added elastic tubes on open-chain knee extensor strength training

Attaching elastic tubes (ETs) to resistance training machines can affect the exercise load profile. The purpose of this study was to assess the training effects of added ETs, which were strategically attached to provide additional loads only during the deceleration phase of the knee extension exercise. Twenty-two healthy participants, assigned to either an experimental group (with ETs) or a control group (without ETs), participated in a 12-week strength-training program using a knee extension exercise machine. The acceleration effects were quantified and a method of attaching the ETs to the knee extension machine was developed. The effects of the added ETs were analysed by testing dynamic and isometric maximum contractions at four knee flexion angles (10°, 30°, 50°, and 80°). Analyses of covariance with the initial values as the covariate were used to examine the ET effects. A greater increase in isometric maximum strength was found in the experimental group than in the control group at knee flexion angles of 10° [effect size (ES) = 2.25] and 30° (ES = 1.18). No significant difference in the dynamic maximum strength was found between the groups. The use of ETs increased strength at smaller knee flexion angles with quadriceps that were relatively short.