Association between knee-to-hip flexion ratio during single-leg vertical landings,and strength and range of motion in professional soccer players

Abstract

The aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = ?0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload.     

Closing the PDF gap: ReadCube’s experiments in reader‐focused design

Key points

• Twenty years ago, a fraction of articles were paired with supplements; now, one in five research stories go beyond PDF.
• Why has the evolution of research content's delivery vehicles lagged behind the evolution of the research story?
• Hyperlinked in‐line references are the most used feature of the Enhanced PDF – exposing faster, easier ways to follow the path of research.
• Discovery need not start and end with the search engine – it can start within the PDF itself.
• Discovery is not a solitary process; therefore, content platforms must support collaboration to drive readership.

     

Relationships amongst cultural dimensions,educational expenditure and class size of different nations

Many studies have concentrated on investigating educational expenditure and pupil–teacher ratio to see how these two factors can influence the quality of education. This study chooses to examine these two educational factors from a different perspective. If educational expenditure and pupil–teacher ratio really have a significant impact on the quality of education as many studies have claimed, it is important to step back and understand why some regions choose to have high/low educational expenditure and high/low pupil–teacher ratios. This study found that culture has an important impact on these two educational factors. Hofstede's cultural dimensions, namely Power Distance and Individualism, were applied and results showed that these two cultural dimensions, when applied to 43 regions around the world, demonstrated a significant impact on educational expenditure and pupil–teacher ratio.     

From the Adam Smith Institute to the Zapatistas: An Internet Gateway to all development knowledge

This article critically examines a major World Bank Internet initiative, the Development Gateway. It describes the importance of the World Bank as the Knowledge Bank and the threats posed by the Internet to its near monopoly of development thinking. The Bank's Gateway plan attempts to bring together views of all stakeholders on a large number of topics at both global and country level. The article argues that this effort is naive, impossible and dangerous. The initiative, which will marginalise dissident and minority views, reveals biases and misunderstandings in the World Bank's overall approach to knowledge for development.     

New forms of government school provision – an international comparison

Driven by a desire to improve academic outcomes and transform ‘failing’ schools, governments around the world have often turned to the development of new forms of state-funded school. This paper looks at three such instances of the introduction of new forms of schooling, within three urban localities (academy schools in London; charter schools and small schools of choice in New York City; and Schools of Tomorrow in Rio de Janeiro). It considers the extent to which these types of school did improve academic outcomes for their students and draws comparisons across each case study in order to understand their similarities and differences. It concludes that although the quasi-marketisation of school systems through the introduction of new (often private) providers might improve outcomes, this is not the only means by which improvement can be attained; and that instead the introduction of new forms of school may be successful because this enables certain other changes to happen. It highlights the limited nature of impact evidence available in all instances, which restricts our ability to properly evaluate the effect of new school types on outcomes.     

Exploring Factors That Promote Online Learning Experiences and Academic Self-Concept of Minority High School Students

The rapid growth of online education at the K-12 level in recent years presents the need to explore issues that influence the academic experiences of students choosing this method of learning. In this study, we examined factors that promote/hinder the learning experiences and academic self-concept of minority students attending an online high school. Qualitative interviews were conducted with twenty-four African American, and sixteen Hispanic high school students. The results showed that collaborative learning activities, access to resources, time convenience, student-teacher interactions, student-student interactions, improved academic behavior, and parental support helped to enhance online learning experiences and academic self-concept of the minority students. On the contrary, the lack of social presence, and the lack of cultural inclusion in course content constrain online learning experiences and academic self-concept of the students. The findings revealed some similarities between factors that influence minority students learning experiences online, and in face-to-face setting. The study also highlighted the need for teachers of online courses to understand the cultural backgrounds of minority students, and to use their knowledge to improve the learning experiences and academic self-concept of these students. Implications for teaching minority high school students in an online environment, as well as suggestions for future research are provided. (Keywords: minority students, K-12 online school, factors, online learning, self-concept)     

Validating the Sedentary Sphere method in children: Does wrist or accelerometer brand matter?

This study aimed to validate the Sedentary Sphere posture classification method from wrist-worn accelerometers in children. Twenty-seven 9–10-year-old children wore ActiGraph GT9X (AG) and GENEActiv (GA) accelerometers on both wrists, and activPAL on the thigh while completing prescribed activities: five sedentary activities, standing with a phone, walking (criterion for all 7: observation) and 10-min free-living play (criterion: activPAL). In an independent sample, 21 children wore AG and GA accelerometers on the non-dominant wrist and activPAL for two days of free-living. Per cent accuracy, pairwise 95% equivalence tests (±10% equivalence zone) and intra-class correlation coefficients (ICC) analyses were completed. Accuracy was similar, for prescribed activities irrespective of brand (non-dominant wrist: 77–78%; dominant wrist: 79%). Posture estimates were equivalent between wrists within brand (±6%, ICC > 0.81, lower 95% CI ≥ 0.75), between brands worn on the same wrist (±5%, ICC ≥ 0.84, lower 95% CI ≥ 0.80) and between brands worn on opposing wrists (±6%, ICC ≥ 0.78, lower 95% CI ≥ 0.72). Agreement with activPAL during free-living was 77%, but sedentary time was underestimated by 7% (GA) and 10% (AG). The Sedentary Sphere can be used to classify posture from wrist-worn AG and GA accelerometers for group-level estimates in children, but future work is needed to improve the algorithm for better individual-level results.     

Relationship between an editor in chief's commentary publications and the impact factor of cardiovascular medicine journals

Journal impact factor (IF) inflation is suggested as a problem resulting from commentaries published by the editors in chief (EiCs) of their respective journals. However, it is unclear whether this is a systemic problem across the top thirty cardiovascular medicine journals. Therefore, the purpose of this investigation was to examine the relationship between the number of commentaries written by an EiC and their journal''s IF and Eigenfactor (Ef). Utilizing Spearman rank partial correlations controlling for length of service as the EiC, significant moderate correlations were found between the number of commentaries and the number of first-author commentaries by the EiC and the IF of their journal (r=0.568, p=0.001 and r=0.504, p=0.005; respectively). A weak but still significant correlation was found between the number of commentaries by the EiC and the Ef of their journal (r=0.431, p=0.020). The reason for these correlations is unclear, and whether the methodology used to compute the IF and Ef should be modified needs further research.     

Weeding with Wisdom: Tuning Deselection of Print Monographs in Book-Reliant Disciplines

As university libraries transition to digital collections and new services, their book deselection projects often lead to the adoption of cross-discipline quantitative weeding criteria (such as age and low circulation) in the interest of speed and presumed fairness. Cross-discipline quantitative rubrics, however, can have unintended negative consequences when applied to disciplines such as history and literature that rely on older books with low circulation statistics. The authors argue for a discipline-differentiated approach to weeding academic library collections that can employ quantitative criteria for disciplines, such as in the sciences, that are more reliant on current materials and qualitative criteria for disciplines, such as in the humanities, whose scholars benefit from ready access to older and low-use books.