Alternative assessment of knee joint muscle balance of soccer players through total work-based hamstring: quadriceps ratios     

Felipe Minozzo  Carlos Leonardo Figueiredo Machado  Eurico Nestor Wilhelm  Rafael Grazioli  Ronei Silveira Pinto 《European Journal of Sport Science》2018,18(10):1398-1404

Isokinetic hamstring-to-quadriceps (H:Q) ratios are frequently used to assess knee muscle strength imbalances and risk of injuries/re-injuries. The use of peak torque (PT) or total work (TW) to estimate joint stability may lead to different results because of the differences between these two neuromuscular variables. Thus, the current study aimed to compare the conventional and functional H:Q ratios calculated by PT and TW. Ninety-three male professional soccer players from Brazilian first division teams performed isokinetic concentric and eccentric contractions of the quadriceps and the hamstrings at 60°/s. Muscle strength balance was calculated using the conventional torque ratio (CTR) and conventional work ratio (CWR), functional torque ratio (FTR) and functional work ratio (FWR) were highly and moderately correlated between them (r?=?0.83 and r?=?0.73, respectively). The Wilcoxon statistical test revealed significant differences between CTR and CWR, as well as FTR and FWR (p?T-test demonstrated significant differences in mean CTR–CWR and FTR–FWR, whereas Bland–Altman plots showed non-consistent bias. In addition, the chi-square test demonstrated significant differences between players below the conventional reference values and functional reference values (p?相似文献   

Clones identification of Sequoia sempervirens (D.Don) Endl.in Chile by using PCR-RAPDs technique     

Manuel TORAL IBAEZ  Margarita CARU  Miguel A.HERRERA  Luis GONZALEZ  Luis M.MARTIN  Jorge MIRANDA  Rafael M.NAVARRO-CERRILLO 《Journal of Zhejiang University. Science. B》2009,10(2)

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D.Don) Endl.in Chile.Ten (out of 34) clones from introduction trial located in Voipir-Viilarrica,Chile,were studied.The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction.The PCR tests were carried out employing 10-mer random primers.The amplification products were detected by electrophoresis in agarose gels.Forty nine polymorphic bands were obtained with the selected primers (BG04,BF07,BF 12,BF13,and BF 14) and were ordered according to their molecular size.The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA).Of the primers tested,5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism.A total of 49 polymorphic RAPD bands were detected out of 252 bands.The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones,suggesting a geographic relationship.The results indicate that the RAPD markers permitted the identification of the assayed clones,although they are derived from the same geographic origin.  相似文献   

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique     

Manuel Toral Ibañez  Margarita Caru  Miguel A. Herrera  Luis Gonzalez  Luis M. Martin  Jorge Miranda  Rafael M. Navarro-Cerrillo 《Journal of Zhejiang University. Science. B》2009,10(2):112-119

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin. Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile  相似文献   

Effect of endpoint conditions on position and velocity near impact in tennis     

Duane Knudson  Rafael Bahamonde 《Journal of sports sciences》2013,31(11):839-844

Smoothing to obtain accurate position and velocity data near impacts in sport biomechanics studies is complicated by the accelerations of impact, endpoint effects and the smoothing technique used. Wrist goniometric data with two levels of random noise added were used to examine three endpoint modelling conditions for obtaining accurate position and velocity data at impact in the tennis forehand. The common approach of smoothing through impact created distortions of the position signal up to 100 ms before impact and resulted in consistent underestimations (-3.2%) of wrist angle and angular velocity (-67.9%) at impact. New linear and polynomial extrapolation conditions smoothed with all techniques provided lower root mean squared errors than the smoothing-through-impact condition, with discrete wrist positions at impact within 1.1% of the criterion data. Both the new linear and polynomial conditions can be used to make more accurate angular position and velocity estimates for tennis impacts, whereas the smoothing-through-impact condition creates spurious decreases in speed before impact that in the past have been assumed to be aspects of skilful movement.  相似文献   

Baseball     

Rafael Escamilla  Glen Fleisig  Steven Barrentine  James Andrews  Claude Moorman III 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):213-228

The purpose of this study was to quantify and compare kinematic, temporal, and kinetic characteristics of American and Korean professional pitchers in order to investigate differences in pitching mechanics, performance, and injury risks among two different cultures and populations of baseball pitchers. Eleven American and eight Korean healthy professional baseball pitchers threw multiple fastball pitches off an indoor throwing mound positioned at regulation distance from home plate. A Motion Analysis three‐dimensional automatic digitizing system was used to collect 200 Hz video data from four electronically synchronized cameras. Twenty kinematic, six temporal, and 11 kinetic variables were analyzed at lead foot contact, during the arm cocking and arm acceleration phases, at ball release, and during the arm deceleration phase. A radar gun was used to quantify ball velocity. At lead foot contact, the American pitchers had significantly greater horizontal abduction of the throwing shoulder, while Korean pitchers exhibited significantly greater abduction and external rotation of the throwing shoulder. During arm cocking, the American pitchers displayed significantly greater maximum shoulder external rotation and maximum pelvis angular velocity. At the instant of ball release, the American pitchers had significantly greater forward trunk tilt and ball velocity and significantly less knee flexion, which help explain why the American pitchers had 10% greater ball velocity compared to the Korean pitchers. The American pitchers had significantly greater maximum shoulder internal rotation torque and maximum elbow varus torque during arm cocking, significantly greater elbow flexion torque during arm acceleration, and significantly greater shoulder and elbow proximal forces during arm deceleration. While greater shoulder and elbow forces and torques generated in the American pitchers helped generate greater ball velocity for the American group, these greater kinetics may predispose this group to a higher risk of shoulder and elbow injuries.  相似文献   

AN OVERVIEW OF ENVIRONMENTAL EDUCATION IN A SAMPLE OF EUROPEAN COUNTRIES WITH PARTICULAR REFERENCE TO PROVISIONS OF DISTANCE TEACHING     

Farrukh Tahir  Walter Leal Filho 《Higher Education in Europe》1996,21(2-3):139-152

This article gives an overview of current provisions for environmental education in the context of distance education programmes in a sample of European countries. The methodology, that was employed by means of a postal survey aimed at identifying current trends in environmental education in relation to distance teaching, is described. The sample surveyed consisted of approximately 500 higher education institutions, members of the Association of European Universities (CRE), over 200 of which had signed the CRE‐Copernicus Universities Charter on Sustainable Development. The article presents a regional summary of the research findings that formed part of a larger enquiry into the status of environmental education in European countries, Commonwealth countries, and individual countries such as the United Kingdom and Pakistan.  相似文献   

Students’ conception of infinite series     

Rafael Martínez-Planell  Ana Carmen Gonzalez  Gladys DiCristina  Vanessa Acevedo 《Educational Studies in Mathematics》2012,81(2):235-249

This is a report of a study of students’ understanding of infinite series. It has a three-fold purpose: to show that students may construct two essentially different notions of infinite series, to show that one of the constructions is particularly difficult for students, and to examine the way in which these two different constructions may be built so that we may uncover ways to help students improve their understanding. The theoretical framework consists of action–process–object–schema theory and the specific model of conceptions in Balacheff’s theory of conception, knowing, and concept. Approaching the problem from these two different theoretical perspectives allows us to provide different and at the same time complementary explanations of observed phenomena. The two different infinite series constructions are, briefly stated, series as an infinite unending process of addition and series as a sequence of partial sums. Students are found to have difficulty building an understanding of series as a sequence of partial sums and thus tend to have difficulty in problem situations that require this interpretation. The study uses semi-structured interviews with 10 graduate students. The interviews explore situations that might give insight into students’ notion of the sequence of partial sums.  相似文献   

Scenario planning in public libraries: a discussion     

Matt Finch  Rafael Ramirez 《Public Library Quarterly》2013,32(4):394-407

The authors explore the use of scenario planning in public libraries via a Q&A discussion. They discuss the impact of unexpected events and unwelcome trends on libraries’ future, explain the distinction between scenario work and forecasting, and outline a practical approach to devising and delivering scenario planning activities at a local library level. This discussion, which took place at Oxford University’s Said Business School on 23 August 2018, explores the use of scenario planning in public libraries.  相似文献   

Integrating Video Documentary Into the Classroom: A Community Assessment Assignment     

Samantha G. Levinson  Keith Caldwell  Helen E. Petracchi  Sandra Wexler  Rafael Engel 《Journal of Teaching in Social Work》2013,33(2):160-175

Community assessment is a strategy commonly taught to social work students to identify a community’s strengths and challenges. This article describes the value of using video documentary as part of a community assessment assignment. We identify the advantages of using video documentary in the assessment process and the reporting of findings. We discuss the preproduction, production, and postproduction steps necessary to produce a video documentary and illustrate how such assignments can be incorporated into a social work course. We conclude by identifying the educational benefits accrued to students.  相似文献   

The assessment of severely intellectually disabled students     

Joakim Isaksson  Rafael Lindqvist  Erik Bergström 《欧洲特需教育杂志》2013,28(1):75-91

In 1995 it became mandatory to establish individual educational plans (IEPs) for children with special educational needs in the Swedish compulsory school. On the basis of the pupils' needs, such a plan should contain information about the pupils' school situation and performance, the class, teaching etc. The aim of this article was to study how special educational needs are defined and described and what support measures the school is suggesting, using IEPs from a sample of Swedish compulsory schools. Our study is based on an analysis of IEPs for pupils with special educational needs in the nine‐year compulsory school in a municipality in northern Sweden. A strategic selection of three compulsory schools was made and we restricted the study to grades 3, 6 and 9. The method used to analyse the IEPs was content analysis. Using different theories within the field of special education and disability studies, we have tried to discern to what extent the problems described, and the proposed measures (intervention), are related to predetermined theoretical models of disability and special needs education. Our analysis indicates that difficulties are predominantly attributed to the pupils' shortcomings and individual characteristics, and the same holds for the recommended measures. Another interesting finding is that a number of the plans were established without involving the parents, and many of them did not even know that their child had an IEP. Finally, we discuss our findings in relation to different research traditions within the field of special education.  相似文献