Mechanical determinants of acceleration and maximal sprinting speed in highly trained young soccer players

Abstract

The aim of the present study was to examine, in highly trained young soccer players, the mechanical horizontal determinants of acceleration (Acc) and maximal sprinting speed (MSS). Eighty-six players (14.1 ± 2.4 year) performed a 40-m sprint to assess Acc and MSS. Speed was measured with a 100-Hz radar, and theoretical maximal velocity (V₀), horizontal force (F₀) and horizontal power (P_max) were calculated. Within each age group, players were classified as high Acc/fast MSS (>2% faster than group mean), medium (between ?2% and +2%), and low/slow (>2% slower). Acc and MSS were very largely correlated (?0.79; 90% confidence limit [?0.85; ?0.71]). The determinants (multiple regression r² = 0.84 [0.78; 0.89]) of Acc were V₀ (partial r: 0.80 [0.72; 0.86]) and F₀ (0.57 [0.44; 0.68]); those of MSS (r² = 0.96 [0.94; 0.97]) were V₀ (0.96 [0.94; 0.97]) and P_max (0.73 [0.63; ?0.80]). High/Med have likely greater F₀ (Cohen’s d: +0.8 [0.0; 1.5]), V₀ (+0.6 [?0.1; 1.3]) and P_max (+0.9 [0.2; 1.7]) than Low/Med. High/Fast have an almost certainly faster V₀ (+2.1 [1.5; 2.7]) and a likely greater P_max (+0.6 [?0.1; 1.3]) than High/Med, with no clear differences in F₀ (?0.0 [?0.7; 0.6]). Speed may be a generic quality, but the mechanical horizontal determinants of Acc and MSS differ. While maximal speed training may improve both Acc and MSS, improving horizontal force production capability may be efficient to enhance sprinting performance over short distances.     

A review of educators' attitudes toward handicapped children and the concept of mainstreaming

Literature is reviewed related to the attitudes of educators toward handicapped children and the concept of mainstreaming these youngsters into regular class settings. Opinionnaire data suggest that regular class educators, particularly those with little formal training or experience in special education, do not favor mainstreaming. Moreover, these educators view handicapped children as generally less able to benefit from schooling. Research is also reviewed that documents the relationship between teachers' attitudes toward individual pupils and the differential instructional treatment of children. Finally, efforts to modify the attitudes and perceptions of educators toward handicapped children and mainstreaming are presented.     

Forgeries of Fossils in “Amber”: History,Identification and Case Studies

The appeal of ancient fossilized tree resin, or amber, has made pieces with animal and plant inclusions particularly prized. Unfortunately, amber forgeries are more convincingly and routinely made than most other kinds of fossils, by embedding organisms in natural resins (e.g., copal) or synthetic resins (especially polyester) or by filling a carved niche in a natural piece of amber with resin and a modern inclusion. The confusion of organisms in copal (forged and natural) for ones in amber has a long history. Reviewed here are simple tests for discerning forgeries and natural inclusions in both substances. We discuss an old but sophisticated technique for crafting amber forgeries from authentic amber and present several new examples from old collections in two large museum collections. Also discussed is the widespread use of polyester resin forgeries in the Dominican Republic and Mexico.     

Drivers and barriers to the utilisation of gamification and game-based learning in universities: A systematic review of educators' perspectives

While gamification and game-based learning have both been demonstrated to have a host of educational benefits for university students, many university educators do not routinely use these approaches in their teaching. Therefore, this systematic review, conducted using the PRISMA guidelines, sought to identify the primary drivers and barriers to the use of gamification and game-based learning by university educators. A search of multiple databases (Web of Science, Scopus and EBSCO (Business Source Complete; ERIC; Library, Information Science & Technology Abstracts)) identified 1330 articles, with 1096 retained after duplicates were removed. Seventeen articles (11 quantitative, two mixed-methods and four qualitative) were included in the systematic review. The primary drivers described by the educators that positively influenced their gamification and game-based learning usage were their beliefs that it encourages student interactions and collaborative learning; provides fun and improves engagement; and can easily be used by students. Alternatively, the university educators' major barriers included a lack of time to develop gamification approaches, lack of proven benefits and classroom setting issues. Many of these and other less commonly reported drivers and barriers can be categorised as attitudinal, design-related or administrative in nature. Such categorisations may assist university educators, teaching support staff and administrators in better understanding the primary factors influencing the utilisation of gamification and game-based learning and develop more effective strategies to overcome these barriers to its successful implementation.

Practitioner notes

What is already known about this topic

• Gamification and game-based learning may have many benefits for university students.
• The majority of university educators do not routinely use gamification and game-based learning in their teaching.

What this paper adds

• University educators' major drivers that positively influence the use of gamification and game-based learning include their perceptions that it encourages student interactions and collaborative learning, provides fun and improves engagement and can easily be used by students.
• University educators' major barriers that negatively influence the use of gamification and game-based learning include their perceptions of a lack of time to develop gamification approaches, lack of proven benefits and classroom setting issues.
• These drivers and barriers may be classified as attitudinal, design-related and administrative, with these categories providing a useful way for universities to develop strategies to better support educators who wish to use these approaches in their teaching.

Implications for practice and policy

• Attitudinal factors such as university educators' intention to use gamification and game-based learning are influenced by a host of their perceptions including attitude, perceived usefulness and ease of use.
• A range of design-related and administrative barriers may need to be overcome to increase the use of gamification and game-based learning in the university sector.

     

Leadership Styles of Russian Enterprise Managers: The Effect of Transactional and Transformational Behaviors on Employees' Evaluation of Managerial Performance

The purpose of this research was to identify leadership styles of today's Russian enterprise managers and to determine how these styles are related to employees' subjective evaluation of managerial performance. The survey was based on Bass and Avolio's MLQ5x leadership styles instrument. Valid responses were received from 1,216 managers and employees at three large manufacturing enterprises located in Moscow. The study results suggest that Russian managers used three well‐known leadership styles—transactional, transformational, and laissez‐faire. However, the laissez‐faire style was not prevalent. Overall, transactional leadership was used more often than transformational leadership. Transactional contingent ceward leadership was used more often than any other approaches. Charisma and Individualized Consideration have received the lowest scores among the transformational leadership style dimensions. Tests of the relationship between leadership styles and managerial performance measures indicate that transformational leadership‐and one of its components, Charisma‐had the strongest relationship with positive outcomes. Implications for developing leadership training programs in Russia and for the transfer of Western training and development approaches are discussed.     

Transformation of teacher training in a rapidly evolving digital environment

Education and Information Technologies - Today the increasing level of technology in education requires corresponding skills from the teachers. However, they often do not have them. The purpose of...     

Virtual Knowledge‐Sharing Communities of Practice at Caterpillar: Success Factors and Barriers

This article reports the results of a qualitative study of success factors and barriers to the development of virtual knowledge‐sharing communities of practice at Caterpillar Inc., a Fortune 100 multinational corporation. The study identified several prerequisites for successful knowledge management through virtual communities of practice: knowledge sharing as a key element of the corporate culture; employees regarding knowledge as a public good belonging to the whole organization, and not as their individual asset; communities self‐organizing around specific performance‐related problems or areas of professional interest of their members; and communities supported by volunteer managers and active core groups of experts. At the same time, the study has identified a number of important barriers to virtual community development. Specifically, even when employees give the highest priority to the interests of the organization, they tend to shy away from contributing knowledge for a variety of other reasons not related to information hoarding. In addition, corporate security considerations and concerns about the accuracy of the information and the potential information overload could clash with the need to promote spontaneous generation of information. Suggestions for overcoming the identified barriers, future research directions, and implications for HRD professionals are formulated.