New curve sprint test for soccer players: Reliability and relationship with linear sprint     

Alberto Fílter  Jesús Olivares  Alfredo Santalla  Fabio Y. Nakamura  Irineu Loturco  Bernardo Requena 《Journal of sports sciences》2020,38(11-12):1320-1325

ABSTRACT

The speed performance is involved not only in linear sprints, but also in a wide spectrum of multi-directional movements, such as curve sprinting. Curved sprint can be defined as sprint with gradual and continuous change of direction (COD). Although ~85% of the actions performed at maximum velocity in a professional soccer league are curvilinear sprints, there is not any specific test to assess this ability. This study aimed to analyse the reliability of a new curve sprint test, and compare its results with those obtained by soccer players in linear sprint. Forty experienced soccer players performed 3 attempts of curve sprint (using the penalty arc) to right and left side (17 m), and 3 linear sprints (17 m) in two different days. The ICCs (inter-session reliability) were 0.93 for sprint curve right side (CSRS) and 0.89 for sprint curve left side (CSLS), considered “acceptable”. The CVs (intra-session reliability) were 0.87% in CSRS and 1.15% in CSLS. The coefficient of determination (R²) between linear and curve sprinting was ~35%. The association between curve sides was “very large” (r = 0.878; p < 0.01). In summary, we showed that “curve sprint test” is highly reliable, and that curvilinear and linear sprints are different and independent actions.  相似文献   

Comparison of Haptic and Biometric Properties,Bacterial Load,and Student Perception of Fixative Solutions: Formaldehyde Versus Chilean Conservative Fixative Solution with and without Formaldehyde in Pig Kidneys     

Marianne Skopnik-Chicago  Katherine Poblete-Cordero  Natali Zamora  Roberto Bastías  Pablo A. Lizana 《Anatomical sciences education》2021,14(6):836-846

One of the most widely used solutions to fix and preserve organic tissues is formaldehyde, despite reservations regarding its toxicity and the fact that formaldehyde-embalmed bodies lose their original characteristics. Anatomy laboratories have been replacing formaldehyde with solutions that retain the characteristics of fresh tissue. For this purpose, alternative solutions with a very low concentration of formaldehyde or without any formaldehyde have been analyzed. The objective of this study was to compare biometry, coloration, haptic properties, and bacterial load on animal specimens (pig kidneys) embalmed with formaldehyde, and with Chilean Conservative Fixative Solution with and without formaldehyde (formaldehyde chCFS and formaldehyde-free chCFS). Also, the perception of health and biological science students toward specimens treated with different solutions was assessed. The results indicated that there were no significant differences in specimens’ retraction, or bacterial load. Students showed a preference for organs embalmed in formaldehyde chCFS and formaldehyde-free chCFS; indicating that with these treatments they could better visualize structures and that the prosections had greater flexibility and the colors were more similar to those of fresh tissue. Additionally, students recommended the material embalmed in formaldehyde chCFS and formaldehyde-free chCFS for anatomy learning. In contrast, students indicated that formaldehyde-fixation negatively affected their practical experience. In conclusion, embalming with formaldehyde chCFS or formaldehyde-free chCFS provides an advantageous practical experience over the use of formaldehyde and may be an alternative to replace the use of formaldehyde in anatomy laboratories.  相似文献   

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

Jonathon Weakley  Shaun McLaren  Carlos Ramirez-Lopez  Amador García-Ramos  Nick Dalton-Barron  Harry Banyard 《Journal of sports sciences》2020,38(5):477-485

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.  相似文献   

A Typology of State Financial Aid Grant Programs Using Latent Class Analysis     

Custer  Bradley D.  Akaeze  Hope O. 《Research in higher education》2021,62(2):175-205

Research in Higher Education - State financial aid grant programs are commonly categorized as either need-based, merit-based, or both, but their initial eligibility requirements include many more...  相似文献   

Promoting a participatory convergence in a Spanish context: an inter-university action research project using visual narrative     

Elia Fernández-Díaz  Carlos Rodríguez-Hoyos  Adelina Calvo Salvador  Gloria Braga Blanco  Lorea Fernández-Olaskoaga  Prudencia Gutiérrez-Esteban 《Educational Action Research》2019,27(3):362-378

ABSTRACT

This article focuses on the deconstruction of an inter-university action research project that has allowed us to rethink our teaching and research, questioning the social, political and ethical dimensions of the university. Following the pre-assembly proposal to promote participatory convergence, organized within the framework of the 1^st Global Assembly for Knowledge Democracy (2017), an action research process was implemented in order to generate systematic inquiry around the current situation of the university and the need to act and rethink our commitment to promoting changes in this context. We have reflected on the meaning of democratization, rethinking the pedagogical relationship with our students and how we critically commit them to promote activism. We generated an environment where we look for the meaning of our practices by means of a visual narrative which has enabled us to weave and identify our own biography and become aware of where we are and why we act in one way or another. We have also focused on the search for the meaning of our actions in relation to the community we belong to and how to deal with the challenges of social justice, encouraging collaboration with other networks in a wider inter-university framework.  相似文献   

Hypocalcemia in an 11 Year Old Child: <Emphasis Type="Italic">A Difficult Case to Treat</Emphasis>     

P. Purohit  D. Khera  K. Singh 《Indian journal of clinical biochemistry : IJCB》2018,33(4):489-490

Hypocalcemia is a laboratory and clinical abnormality that is observed especially in neonates and paediatric patients. Laboratory hypocalcaemia is often asymptomatic but it can manifest as central nervous system irritability, paraesthesia, tetany (i.e. contraction of hands, arms, feet, larynx, bronchioles), seizures, and even psychiatric changes in children. Cardiac function may also be impaired because of poor muscle contractility. We report a unique case of an eleven year old male child who presented with chronic kidney disease associated with severe hypocalcemia, tonic-clonic seizures, hypovitaminosis D but normal electroencephalogram and electrocardiography. The child required prolonged intravenous calcium gluconate therapy to correct his ionised calcium levels.  相似文献   

The role of task and ego-oriented climate in explaining students’ bright and dark motivational experiences in Physical Education     

Luis García-González  Javier Sevil-Serrano  Angel Abós  Nathalie Aelterman  Leen Haerens 《Physical Education & Sport Pedagogy》2019,24(4):344-358

Background: A distinction is made in Achievement Goal Theory (AGT) between task-oriented (i.e. effort, intra-individual progress, and self-comparison) and ego-oriented (i.e. inter-individual progress and normative comparison) climates. Combining insights from AGT and Self-Determination Theory (SDT), studies in the PE context have shown that a task-oriented climate positively relates to need satisfaction, although the findings regarding the motivating role of an ego-oriented climate are inconsistent. Moreover, little is known about the role of task- or ego-oriented climates in explaining experiences of basic psychological need frustration.

Purpose: Grounded in AGT and SDT, the aim of the present study was to examine if experiences of basic psychological need satisfaction and need frustration can explain why task- and ego-oriented climates elicit positive and negative motivational outcomes in PE, respectively.

Research design: Cross-sectional study.

Method: A sample of 524 secondary school students (51.1% boys, M_age?=?14.51; SD?=?1.81) from five different secondary schools participated in this study. Students reported on their perceptions of task- and ego-oriented climates, motivational regulations, basic psychological need satisfaction, and need frustration, as well as positive and negative outcomes in PE. Structural equation modeling was used to investigate our objective.

Results: We found that a task-oriented climate had a strong and positive relationship with basic psychological need satisfaction, eliciting a bright pathway to autonomous motivation and affective attitude. An ego-oriented climate was positively related to basic psychological need frustration, eliciting a dark pathway to amotivation and boredom. A negative cross-path from task-oriented climate to basic psychological need frustration was also found, while no significant cross-paths were found from ego-oriented climate to basic psychological need satisfaction.

Conclusions: This study provides a better understanding of the mechanisms that explain why task- and ego-oriented climates shape students’ motivational experiences in PE lessons. It is suggested that a task-oriented climate elicits a bright pathway towards more optimal functioning, because it fosters experiences of need satisfaction and buffers against experiences of need frustration. In contrast, an ego-oriented climate is primarily positively related to feelings of need frustration and negative motivational outcomes. Practical implications for PE teacher training are discussed.  相似文献   

Reviewing the Variability-Overuse Injury Hypothesis: Does Movement Variability Relate to Landing Injuries?     

Andrew D. Nordin  Janet S. Dufek 《Research quarterly for exercise and sport》2019,90(2):190-205

Purpose: Overuse injuries are common in sport, but complete understanding of injury risk factors remains incomplete. Although biomechanical studies frequently examine musculoskeletal injury mechanisms, human movement variability studies aim to better understand neuromotor functioning, with proposed connections between overuse injury mechanisms and changes in motor variability. Method: In a narrative review, we discuss the variability-overuse injury hypothesis, which suggests repeated load application leads to mechanical tissue breakdown and subsequent injury when exceeding the rate of physiological adaptation. Due to the multidisciplinary nature of this hypothesis, we incorporate concepts from motor control, neurophysiology, biomechanics, as well as research design and data analysis. We therefore summarize multiple perspectives while proposing theoretical relationships between movement variability and lower extremity overuse injuries. Results: Experimental data are presented and summarized from published experiments examining interactions between experimental task demands and movement variability in the context of drop landing movements, along with comparisons to previous movement variability studies. Conclusion: We provide a conceptual framework for sports medicine researchers interested in predicting and preventing sports injuries. Under performance conditions with greater task demands, we predict reduced trial-to-trial movement variability that could increase the likelihood of overuse injuries.  相似文献   

Teacher–student negotiations during context-based chemistry reform: A case study     

Michelle Overman  Jan D. Vermunt  Paulien C. Meijer  Mieke Brekelmans 《科学教学研究杂志》2019,56(6):797-820

Teachers participating in curricular reforms, especially reforms based on constructivism, are expected to bring about change in their teaching approach. This is often a difficult, complex and intensive process, and demands a radical reculturing of the classroom. This is also the case for social constructivist reforms in chemistry education, which are based on a context-based approach. Educational change is a social and interactional process, and during this change teachers will engage in negotiations with their students about the reform. These teacher–student negotiations have a profound impact on the succeeding of the reform. This study explores the teacher–student interactions during the reform that shape and alter the context-based chemistry approach. We focused on two teachers, of whom it was found in an earlier study that one of them succeeded in implementing the reform, while the other one struggled. By following them for one school year, in which in-depth qualitative data was collected through various instruments, we developed insights about the teacher–student negotiations that influenced the educational reform. Three themes emerged from the data: “agency of learning,” “vulnerability,” and “care.” The differences that were found between the teachers regarding these themes help explain why and how the reform can become a success and why the reform often fails to change classroom practice.  相似文献   

Neoliberal values & queer/disability in Margarita with a Straw     

Ryan A. D’Souza  Jessica S. Rauchberg 《Journal of International and Intercultural Communication》2020,13(2):183-196

ABSTRACT

Margarita with a Straw is an Indian movie about a queer/disabled woman exploring her sexuality. The article uses textual analysis with a discursive formation approach to analyze how the protagonist’s queer/disabled identity is constituted vis-à-vis intimate partnerships alongside the promotion of neoliberal values. One relationship with an able-bodied white man takes place within a caregiving dynamic that challenges her independence. The other relationship with a disabled South Asian woman creates an interdependence that bifurcates their identities as disabled-and-queer. The article argues that the promotion of neoliberal values in the context of queer/disability is about independence from dependence on sociopolitical systems.  相似文献