Application of velocity loss thresholds during free-weight resistance training: Responses and reproducibility of perceptual,metabolic, and neuromuscular outcomes

ABSTRACT

The aim of this study was to investigate the differences and long-term reliability in perceptual, metabolic, and neuromuscular responses to velocity loss resistance training protocols. Using a repeated, counterbalanced, crossover design, twelve team-sport athletes completed 5-sets of barbell back-squats at a load corresponding to a mean concentric velocity of ~0.70 m·s^?1. On different days, repetitions were performed until a 10%, 20% or 30% velocity loss was attained, with outcome measures collected after each set. Sessions were repeated after four-weeks. There were substantial between-protocol differences in post-set differential ratings of perceived exertion (dRPE, i.e., breathlessness and leg muscles, AU) and blood lactate concentration (B[La], mmol·L^?1), such that 30%>20%>10% by small to large magnitudes. Differences in post-set countermovement jump (CMJ) variables were small for most variables, such that 30%<20%<10%. Standard deviations representing four-week variability of post-set responses to each protocol were: dRPE, 8–11; B[La], 0.8–1.0; CMJ height, 1.6–2.0; CMJ PPO, 1.0–1.8; CMJ PCV, 0.04–0.06; CMJ 100ms-Impulse, 5.7–11.9. Velocity loss thresholds control the magnitude of perceptual, metabolic, and neuromuscular responses to resistance training. For practitioners wanting to reliably prescribe training that can induce a given perceptual, metabolic, or neuromuscular response, it is strongly advised that velocity-based thresholds are implemented.     

Trajectories of Adjustment in a Brazilian Sample of Street-Involved Youth

Trajectories of adjustment were examined in a sample of street-involved youth across a 1-year period. Participants (N = 113; M_age = 14.18 years; 80.5% male, 91% non-White) were recruited in three Brazilian cities. Interviews conducted at three time points included six measures of physical and psychological adjustment. Unconditional growth models revealed linear declines over time (i.e., improved adjustment) on three indicators: health symptoms, sexual risk behaviors, and negative affect. There were no linear changes in drug use, positive affect, or life satisfaction. Conditional growth models revealed few significant effects for age or gender, but ratings of stressful life events moderated longitudinal changes in health symptoms, drug use, and negative affect. Implications for practice, policy, and theory are discussed.     

Archival Science in Brazil: the establishment of a scientific discipline and its impact on training archivists in the era of information and knowledge

This article addresses the trajectory of Archival Science in Brazil, its extracurricular characteristics and its particular relationship with Information Science within academics, its institutional associations, and some considerations regarding current training for archivists in Brazil. The methodological procedures used included analyzing documents from the National Archive Fonds of Brazil, reviewing archive literature, and interviewing people involved in consolidating Archival Science. This study concludes that Archival Science research is taking place in graduate programs throughout public Brazilian universities and points out that people working with archives now have more advanced training, such as undergraduate degrees in Archival Science or other. This study also focuses on archives as information units, while presenting and reflecting on the demands of training archivists who are faced with the challenges of the working world and the era of information and knowledge—challenges that go beyond merely technical procedures and encompass dynamic planning and orientation activities.     

Relations among positive parenting, children's effortful control, and externalizing problems: a three-wave longitudinal study

In a 3-wave longitudinal study (with assessments 2 years apart) involving 186 early adolescents (M ages of approximately 9.3, 11.4, and 13.4), the hypothesis that parental warmth/positive expressivity predicts children's effortful control (EC) (a temperamental characteristic contributing to emotion regulation) 2 years later, which in turn predicts low levels of externalizing problems another 2 years later, was examined. The hypothesis that children's EC predicts parenting over time was also examined. Parents were observed interacting with their children; parents and teachers reported children's EC and externalizing problems; and children's persistence was assessed behaviorally. Children's EC mediated the relation between positive parenting and low levels of externalizing problems (whereas there was no evidence that children's EC predicted parenting).     

Students with special educational needs and cooperative learning in the ordinary classroom: some learnings from teaching practice

This article presents the results of a study to determine the strategies used by teachers to include students with special educational needs in regular classrooms, primarily using Cooperative Learning strategies. It aims to identify the factors of inclusive learning in order to enhance the participation and learning of all students in the classroom and in their cooperative teams. A qualitative case study was carried out in the context of the teachers participating in a postgraduate course ‘expert in cooperative learning’ offered by the University of Alcalá (Spain), over a period of six years (2011–2017), involving the participation of 176 professional teachers. All the participants attended an annual university continuous training course on cooperative learning. Document analysis, in-depth interviews and a questionnaire designed ad hoc were used. The conclusions include the importance of cooperative work in facilitating inclusive education, with a variety of different strategies used to respond to all students' needs, and those with special educational needs in particular, and the coordination required between teachers and special educational needs specialists to implement those strategies.     

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.     

Curriculum-Integrated Information Literacy (CIIL) in a Community College Nursing Program: A Practical Model

This article describes a strategy to integrate information literacy into the curriculum of a nursing program in a community college. The model is articulated in four explained phases: preparatory, planning, implementation, and evaluation. It describes a collaborative process encouraging librarians to work with nursing faculty, driving students to acquire information literacy competencies, to use information resources as part of their learning process, and to be lifelong learners. The literature reviews the evolution of the concept of informatics in nursing practice and the different blueprints organized to attain information literacy competencies. It also describes studies that have included these competencies into nursing curriculum.     

The Use of Different Translation Devices to Analyze Knowledge-Building in a University Chemistry Classroom

Research in Science Education - This research draws on Legitimation Code Theory (LCT) to understand the epistemic dimension of the higher education classroom discourse of a professor who is well...