The effect of different foot and hand set-up positions on backstroke start performance

Foot and hand set-up position effects were analysed on backstroke start performance. Ten swimmers randomly completed 27 starts grouped in trials (n = 3) of each variation, changing foot (totally immersed, partially and totally emerged) and hand (lowest, highest horizontal and vertical) positioning. Fifteen cameras recorded kinematics, and four force plates collected hands and feet kinetics. Standardised mean difference and 95% confidence intervals were used. Variations with feet immersed have shown lower vertical centre of mass (CM) set-up position (0.16 m), vertical impulse exerted at the hands, horizontal and vertical impulse exerted at the feet (0.28, 0.41, 0.16 N/BW.s, respectively) than feet emerged with hands horizontal and vertically positioned. Most variations with feet partially emerged exhibited higher and lesser vertical impulse exerted at hands than feet immersed and emerged (e.g. vertical handgrip, 0.13, 0.15 N/BW.s, respectively). Variation with feet emerged and hands on the lowest horizontal handgrip depicted shorter horizontal (0.23, 0.26 m) and vertical CM positioning at flight (0.16, 0.15 m) than the highest horizontal and vertical handgrip, respectively. Start variations have not affected 15-m time. Variations with feet partially or totally emerged depicted advantages, but focusing on the entry and underwater biomechanics is relevant for a shorter start time.     

Are the new starting block facilities beneficial for backstroke start performance?

We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.     

Engineering education at a new public university in Brazil: first students’ contact with engineering methods

This paper describes the experience of an introductory discipline to the engineering curricula at the Brazilian Federal University of ABC (UFABC). The university offers a common basic curriculum that must be accomplished by every student and can be followed by professionalising courses. The discipline ‘Introduction to Engineering’ presents the basis of the engineering career, methods and thinking together with professional commitments and regulations. The objective is to help students to consciously choose their careers, minimising the precocity problem in deciding a professional future. The discipline methodology includes activities proposed by the TryEngineering website and from Brazilian engineering councils. Lectures with invited professors introduce UFABC engineering specialities: Aerospace, Bioengineering, Energy, Environmental & Urban, Information, Instrumentation & Automation & Robotics, Management, Materials. This paper reports the proposed activities, results obtained by the students, a methodology critical analysis and the impacts on the following steps of students embracing an engineering career.     

Acute intraocular pressure responses to high-intensity interval-training protocols in men and women

We aimed (1) to test the acute impact of two high-intensity interval-training (HIIT) protocols differing in the level of effort on intraocular pressure (IOP) responses, and (2) to elucidate whether the IOP responses differ between men and women. Twenty-four physically active collegiate (12 men and 12 women) performed three protocols: low-fatigue HIIT (eight 30-m sprints with 60-s of rest), high-fatigue HIIT (eight 30-m sprints with 30-s of rest), and control (walking). IOP was taken at baseline, after sprints and recovery by rebound tonometry. Our data revealed an acute IOP reduction during both HIIT protocols compared to the control condition (effect size [ES]:0.81–1.65). The differences between both HIIT protocols were generally negligible (ES<0.30), however, the reduction of IOP was moderately higher for the low-fatigue HIIT protocol after the 7th (ES: 0.67) and 8th (ES: 0.74) sprints. Women showed a more prominent lowering effect on IOP during the control condition (ES: 0.42–1.02), and during the two first sprints of both HIIT protocols (ES: 0.54–1.03). These findings highlight that a time-efficient HIIT protocol may acutely reduce IOP levels, while low-fatigue HIIT protocol could be recommended since it induced a higher reduction on IOP than the high-fatigue HIIT protocol.     

Analysis of foot strike pattern,rearfoot dynamic and foot rotation over childhood. A cross-sectional study

The purpose of this study was to determine the foot strike patterns (FSP), rearfoot position at initial contact (RPic, i.e., No INV/EVE) and foot rotation in children in relation to age. A total of 932 children aged 3 to 16 years participated in this study. A sagittal and frontal-plane video was recorded using a high-speed camcorder to analyse these variables. There is a significant increase (p < 0.001) of rearfoot strike patterns (RFS) prevalence in relation to age; e.g. preschool children (3–6 years old) displayed an RFS prevalence 46.65% and the adolescent population(15–16 years old) an RFS prevalence 92.20%. The total RFS prevalence in all samples was 69.25%. There was a significant reduction (p < 0.001) of prevalence of RPic in relation to age groups; preschool children displayed a prevalence of RPic 60.37% and the adolescent population 10%. There was a significant reduction (p < 0.001) of prevalence of no foot rotation in relation to age groups; preschool children displayed a prevalence of no foot rotation 48.95% and the adolescent population 13.55%. In conclusion, FSP in children are influenced by age. It is noteworthy that the RFS prevalence of children is lower in comparison to the adult population.     

Internal structure of virtual communications in communities of inquiry in higher education: Phases,evolution and participants' satisfaction

This study investigates the phases of development of synchronous and asynchronous virtual communication produced in a community of inquiry (CoI) by analyzing the internal structure of each intervention in the forum and each chat session to determine the evolution of their social, cognitive and teaching character. It also analyzes the participating higher education students' satisfaction with the activities, with the professors' actions, and with themselves. We use a mixed methodology that includes content analysis of the virtual communications by crossing two categorization systems: (1) type of communication according to the model adopted from Garrison, Anderson and Archer (social, cognitive and teaching presence) and (2) phases in the evolution of the communication (initiation, proposal, development, opinion/closing and good‐byes). The data are relevant to the students' satisfaction and grades earned. The results suggest differences in the quantity and content of the communication in each phase and an evolution from social to cognitive elements, ending with social contributions. The students are satisfied with the virtual communications related to both the activities and the professors and evaluate themselves positively.     

跳远最佳起跳角并非45°

跳远选手在助跑后能获得一个很大的水平速度,在起跳阶段需要产生一个垂直速度。在理想情况下,运动员希望在不损失任何水平速度的情况下产生一个尽可能大的垂直速度。但事实上,这是不可能实现的。要想获得垂直速度就必须消耗一定的水平速度。产生的垂直速度越大,水平速度的损耗相应地也会越大。因此,在产生垂直速度和维持水平速度之间寻找一个度是至关重要的。一般情况下,著名教练员认为能够获得的垂直速度是相当有限的,适宜的起跳角一般在20o左右。这表明,在起跳时有40%的水平速度转化成垂直速度。但是,Mackenzie最近提出,跳远选手应采用更…     

PISA as a Political Tool in Spain: Assessment Instrument,Academic Discourse and Political Reform

This study examines to what extent there is a sort of “political appropiation” by political parties when they seek to set a discourse about the Spanish PISA outcomes. We have consistently found that programs for assessing the competencies of students, especially PISA, have become tools of rationalization and the legitimization of education policies in both the national and territorial contexts. Furthermore, each regional government focuses its discourse on what it feels to be its strong points, that is, a clear “self-justifying reading” of PISA outcomes.     

Grading Multiple Choice Exams with Low-Cost and Portable Computer-Vision Techniques

Although technology for automatic grading of multiple choice exams has existed for several decades, it is not yet as widely available or affordable as it should be. The main reasons preventing this adoption are the cost and the complexity of the setup procedures. In this paper, Eyegrade, a system for automatic grading of multiple choice exams is presented. While most current solutions are based on expensive scanners, Eyegrade offers a truly low-cost solution requiring only a regular off-the-shelf webcam. Additionally, Eyegrade performs both mark recognition as well as optical character recognition of handwritten student identification numbers, which avoids the use of bubbles in the answer sheet. When compared with similar webcam-based systems, the user interface in Eyegrade has been designed to provide a more efficient and error-free data collection procedure. The tool has been validated with a set of experiments that show the ease of use (both setup and operation), the reduction in grading time, and an increase in the reliability of the results when compared with conventional, more expensive systems.