Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist     

Johannes Funken  Kai Heinrich  Steffen Willwacher  Ralf Müller  Jonas Böcker  Hiroaki Hobara 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):75-87

The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level.  相似文献   

The load-velocity profile differs more between men and women than between individuals with different strength levels     

Alejandro Torrejón  Carlos Balsalobre-Fernández  G. Gregory Haff 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):245-255

This study aimed to determine the suitability of the load-velocity relationship to prescribe the relative load (%1RM) in women, as well as to compare the load-velocity profile between sexes and participants with different strength levels. The load-velocity relationship of 14 men (1RM: 1.17 ± 0.19) and 14 women (1RM: 0.66 ± 0.13) were evaluated in the bench press exercise. The main findings revealed that: (I) the load-velocity relationship was always strong and linear (R² range: 0.987–0.993), (II) a steeper load-velocity profile was observed in men compared to women (Effect size [ES]: 1.09), with men showing higher velocities for light loads (ES: ? 0.81 and ? 0.40 for the y-intercept and 30%1RM, respectively), but women reporting higher velocities for the heavy loads (ES: 1.14 and 1.50 at 90%1RM and 100%1RM, respectively); and (III) while the slope of the load-velocity profile was moderately steeper for weak men compared to their strong counterpart (ES: 1.02), small differences were observed between strong and weak women (ES: ? 0.39). While these results support the use of the individual load-velocity relationship to prescribe the %1RM in the bench press exercise for women, they also highlight the large disparities in their load-velocity profile compared to men.  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   

Comfort assessment of running footwear: Does assessment type affect inter-session reliability?     

Julia Lindorfer  Josef Kröll  Hermann Schwameder 《European Journal of Sport Science》2019,19(2):177-185

Assessing comfort of running footwear reliably is challenging. The purpose of this study was to compare the intra-rater reliability between different assessment types, to calculate intra-individual reliability scores and to evaluate the effect of rater selection based on individual reliability scores on group level reliability. Three assessment types: ranking, Visual Analogue Scale (VAS), and Likert Scale (LS) were provided twice in six separate sessions among 30 participants, who assessed comfort of five shoes after treadmill running. Spearman's rho provided an evaluation of inter-session relative reliability and typical error as a measure of absolute reliability for each assessment type. Ranking (r?=?0.70, 95% confidence interval [CI] 0.61–0.78) yielded the highest relative reliability for overall comfort, followed by VAS (r?=?0.67, 95% CI 0.56–0.75) and LS (r?=?0.63, 95% CI 0.52–0.72), with large-scale overlaps of CIs between assessment types. The same order of assessment types was found for the percentage of reliable raters (r?≥?0.7) with 60% in ranking scale, 47% in VAS and 37% in LS. Forming subgroups corresponding to the intra-individual reliability substantially increased group level reliabilities. Based on measures of relative reliability, an extreme reduction in resolution as provided by the ranking from pairwise comparisons seems to be a valuable tool in footwear comfort assessments if assessment time is of minor importance. No preference can be provided for the two investigated rating scales. Besides the assessment type, a selection of the best raters in additional reliability checks seems to be a prerequisite for further comfort-related studies.  相似文献   

The concept of ethnicity in social psychological research: Definitional issues     

Hanna Zagefka 《Int J Intercult Relat》2009,33(3):228-241

Although ethnicity frequently features in current quantitative social psychology, it is rarely theorised. This paper starts by reviewing how ethnicity has been conceptualised in other social sciences. A working definition of ethnicity is provided, and an argument for moderate constructivism is advanced. Then, it is discussed how ethnicity has been treated in some of the major traditions in quantitative social psychology, and problems arising from this are highlighted. Firstly, the way ethnicity is discussed in much psychological work leads to a terminological confusion. Secondly, an overly strong focus on generic identity processes prevalent among some social identity researchers bears the danger of excluding a range of important phenomena related to ethnicity from scientific observation. Thirdly, the way in which ethnicity is conceptualised in much of quantitative social psychology (as evinced by psychological theorising, writing, and methodological choices) is incompatible with the notion of ethnicity as constructed. Ignoring the constructed nature of ethnicity has negative consequences for our ability to interpret research findings, for the well-being of participants, and it can have negative ethical and political implications. Practical steps that might be taken in order to avoid these perils in future research are discussed.  相似文献   

A “Deleterious” Driver: The “First Teacher” Reform in Sweden     

Ian Hardy  Karin Rönnerman 《Scandinavian Journal of Educational Research》2019,63(5):805-818

This article investigates the implementation of the “förstelärare” or “First teacher” reform in Sweden. We draw upon the insights of a superintendent, union official, principal, three First teachers, and two of their colleagues in one school, and recent literature on career development reform. We employ Michael Fullan’s overview of the “right” and “wrong” drivers of educational reform to analyse the extent to which the First Teacher initiative cultivated productive “professional capital.” The research reveals: how broader national policy aims were in clear tension with municipal-wide school development, and school-level development efforts; the perverse effects of a strong focus upon salary on professional conduct; and how an emphasis upon teachers’ roles per se undermined the espoused policy focus on enhancing teaching. The research cautions against the problematic effects of the initiative on more profession-oriented prerogatives, and how more external, “deleterious,” drivers of reform militate against more productive professional capital.  相似文献   

Measurement and analysis of soil nitrogen and organic matter content using near-infrared spectroscopy techniques   总被引：2，自引：0，他引：2  

He Y  Song HY  Pereira AG  Gómez AH 《Journal of Zhejiang University. Science. B》2005,6(11):1081-1086

Near infrared reflectance （N1R） spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen （N） and organic matter （OM） content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP （standard error of prediction） were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.  相似文献   

Constructivist Approaches in a Dual-Language Classroom     

Ricardo González-Carriedo  Nancy Bustos  Jorge Ordóñez 《Multicultural Perspectives》2016,18(2):108-111

Dual-language programs are becoming increasingly popular among educators and the public in general. In these programs, students aim at attaining full proficiency in English and another language while reaching an academic achievement at or above grade level. This article describes a series of pedagogical practices in the context of dual-language classrooms. We set the discussion across three defining characteristics of our constructivist perspective: learning as collaboration, teachers as facilitators, and language and culture as intertwined elements in schools. In sum, we postulate that dual-language programs bring equity to schools.  相似文献   

Between Tradition and Change: Hunting as Metaphor and Symbol in State Socialist Hungary     

György Majtényi 《Cultural and Social History》2016,13(2):231-248

Through the historic metaphor of hunting the essay examines the lifestyle of the dominant elites of Hungary between 1945 and 1990 on the basis of archival documents, private records, and oral history interviews. The analysis emphasizes the fact that there were interactions between the old, prewar aristocracy and the new state socialist elites. The co-incidence of lifestyles can be viewed through the lens of social and cultural change: new elements hit against the old, shaping and dissolving old behavioural patterns. The article analyses hunting in the contexts of social differentiation and social grouping. Using semiotics the author shows how, even during the era of state socialism, power and social distinctions were articulated on the level of lifestyles, and transmitted via the social, semiotic function of behaviours, patterns of taste, and forms of interaction. Thus, hunting evolved into a metaphor over time in Hungary: it was not only an indispensable part of the everyday life of the elite, but also became a symbol for belonging to it.  相似文献   

Zeitökonomische Aspekte der Nachfrage nach Vereinsleichtathletik im europäischen Vergleich     

Dr. phil. Jens Flatau  Werner Pitsch  Dirk Bogendörfer  Eike Emrich 《Sportwissenschaft》2009,39(2):110-119

In a joint project involving European association staff and sports scientists, basic structural data were collected on British, Swedish, Spanish and German athletics clubs to be used for analysis of hypotheses concerning conditions of participation in sports clubs, particularly by children and adolescents. The results showed clear differences in organizational level as well as membership and activity structures in comparisons between European countries and within Germany. The findings revealed the differential functions and significance of sports clubs in the context of the respective institutions and cultures.  相似文献