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1.
Tachibana K Yashiro K Miyazaki J Ikegami Y Higuchi M 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):44-58
Although it is clear that rowers have a large muscle mass, their distribution of muscle mass and which of the main motions in rowing mediates muscle hypertrophy in each body part are unclear. We examine the relationships between partial motion power in rowing and muscle cross-sectional area of the thigh, lower back, and upper arms. Sixty young rowers (39 males and 21 females) participated in the study. Joint positions and forces were measured by video cameras and rowing ergometer software, respectively. One-dimensional motion analysis was performed to calculate the power of leg drive, trunk swing, and arm pull motions. Muscle cross-sectional areas were measured using magnetic resonance imaging. Multiple regression analyses were carried out to determine the association of different muscle cross-sectional areas with partial motion power. The anterior thigh best explained the power demonstrated by leg drive (r2 = 0.508), the posterior thigh and lower back combined best explained the power demonstrated by the trunk swing (r2 = 0.493), and the elbow extensors best explained the power demonstrated by the arm pull (r2 = 0.195). Other correlations, such as arm muscles with leg drive power (r2 = 0.424) and anterior thigh with trunk swing power (r2 = 0.33 5), were also significant. All muscle cross-sectional areas were associated with rowing performance either through the production of power or by transmitting work. The results imply that rowing motion requires a well-balanced distribution of muscle mass throughout the body. 相似文献
2.
Keitaro Kubo Daisuke Miyazaki Shigeharu Tanaka Shozo Shimoju Naoya Tsunoda 《Journal of sports sciences》2015,33(7):665-669
The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h?1) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners. 相似文献
3.
The purpose of this study was to build a flexible mechanical system with a hydrostatic skeleton. The main components of this system are two type flexible bags. One is a structural bag with constant inner pressure. The other is an actuator bag with controlled inner pressure. To design the system, it was necessary to estimate both structural deformation and driving force. Nu- merical analysis of flexible bags, however, is difficult because of large nonlinear deformation. This study analyzed structural strength and driving force of flexible bags with the nonlinear finite element analysis （FEA） software ABAQUS. The stress con- centration dependency on the bag shape is described and the driving force is calculated to include the large deformation. From the analytical results, this study derives an empirical equation of driving force. The validity of the equation was confirmed by condition-changed analyses and experimental results. 相似文献
4.
While proof is central to mathematics, difficulties in the teaching and learning of proof are well-recognised internationally. Within the research literature, a number of theoretical frameworks relating to the teaching of different aspects of proof and proving are evident. In our work, we are focusing on secondary school students learning the structure of deductive proofs and, in this paper, we propose a theoretical framework based on this aspect of proof education. In our framework, we capture students’ understanding of the structure of deductive proofs in terms of three levels of increasing sophistication: Pre-structural, Partial-structural, and Holistic-structural, with the Partial-structural level further divided into two sub-levels: Elemental and Relational. In this paper, we apply the framework to data from our classroom research in which secondary school students (aged 14) tackled a series of lessons that provided an introduction to proof problems involving congruent triangles. Using data from the transcribed lessons, we focus in particular on students who displayed the tendency to accept a proof that contained logical circularity. From the perspective of our framework, we illustrate what we argue are two independent aspects of Relational understanding of the Partial-structural level, those of universal instantiation and hypothetical syllogism, and contend that accepting logical circularity can be an indicator of lack of understanding of syllogism. These findings can inform how teaching approaches might be improved so that students develop a more secure understanding of deductive proofs and proving in geometry. 相似文献
5.
Takeshi Miyazaki 《Compare》2016,46(5):701-722
This paper reports on research into a continuing professional development (CPD) project, Projet de Renforcement de l’Enseignement des Mathématiques, des Sciences et de la Technologie (PREMST) [Strengthening Mathematics, Science, and Technologies in Education Project]. The literature review reveals few examples of CPD changing the teaching practices of teachers, especially in sub-Saharan Africa. By using the cases of five teachers, this research seeks to understand the complexities of pedagogical change. The research found that PREMST has helped teachers envision how teaching should be conducted, but it has not necessarily brought a positive change in the learning of pupils because it has not changed how teachers think about teaching. Given the difficulties involved in pedagogical change, emphasising specific skills may have been the necessary and practical first step, but changing these teaching practices is not enough. The research found that teachers still paid little attention to the learning of individual pupils. The research concludes that the recently initiated practice of lesson study shows considerable potential to build on what has already been achieved. 相似文献
6.
Annotation of the functions of genes and proteins is an essential step in genome analysis. Information extraction techniques
have been proposed to obtain the function information of genes and proteins in the biomedical literature. However, the performance
of most information extraction techniques of function annotation in the biomedical literature is not satisfactory due to the
large variability in the expression of concepts in the biomedical literature. This paper proposes a framework to improve the
gene function annotation in the literature by considering both the textual information in the literature and the functions
of genes with sequences similar to a target gene. The new framework collects multiple types of evidence as: (i) textual information
about gene functions by matching keywords of the gene functions; (ii) gene function information from the known functions of
genes with sequences similar to a target gene; and (iii) the prior probabilities of gene functions to be associated with an
arbitrary gene by mining the known gene functions from curated databases. A supervised learning method is utilized to obtain
the weights for combining the three types of evidence to assign appropriate Gene Ontology terms for target genes. Empirical
studies on two testbeds demonstrate that the combination of sequence similarity scores, function prior probabilities and textual
information improves the accuracy of gene function annotation in the literature. The F-measure scores obtained with the proposed framework are substantially higher than the scores of the solutions in prior research.
相似文献
| Yi FangEmail: |
7.
This study investigated whether 2-, 3-, and 4-year-olds use their video feedback as a reflection of their current state, even when their feedback was presented with a short temporal delay. In Experiment 1, the effects of 1- and 2-s delayed feedback were examined on an analog of the mark test. In the case of live and 1-s delayed feedback, 3-year-olds passed the test; however, they failed in the case of 2-s delayed feedback. Experiment 2 examined the effect of prior experience of delayed contingency and explorative behavior. The results showed a significant effect of prior experience. These results suggest that detection of visual-proprioceptive contingency contributes to recognition of visual feedback as one's current self. 相似文献
8.
Daisuke Matsui Isao Watanabe Teruhide Koyama Etsuko Ozaki Nagato Kuriyama Shigeto Mizuno 《Journal of sports sciences》2017,35(18):1788-1793
Osteopenia is a condition in which bone mineral density (BMD) is lower than normal. Exercise increases BMD in both the young and adults. This study aimed to compare the radial apparent BMD (aBMD) in Japanese females who are Kendo practitioners (KPs) and those with no regular exercise habits (no-REH). The analysis participants consisted of 45 KPs (mean age: 49.4 years old) and 110 no-REH (mean age: 48.8 years old). Radial aBMD was measured using an ultrasonic bone densitometry system. Radial aBMD in KPs was 196.1 ± 33.9 mg/cm3, and was 182.9 ± 45.3 mg/cm3 in no-REH participants. KPs had significantly higher BMD than no-REH participants. In KPs, left radial aBMD was 196.1 ± 33.9 mg/cm3, and right radial aBMD was 184.5 ± 37.7 mg/cm3. The left radius was also significantly higher than the right radius with respect to aBMD in KPs. After adjusting for age, body mass index, menstrual status, parous women and frequency of milk and dairy intake, the odds ratio (OR) of osteopenia associated with no-REH was 6.58 (95% confidence interval (CI): 1.72–25.1) and the prevalence ratio (PR) of osteopenia associated with no-REH was 4.12 (95% CI: 1.23–13.7). Therefore, the Kendo practice may have a protective efficacy for osteopenia in women. 相似文献
9.
Compositional effects of scholarly culture classroom/school climate on civic knowledge scores of 9th graders in the United States were examined using the International Association for the Evaluation of Educational Achievement (IEA) 1999 Civic Education Study data. Following Evans et al. (2010, 2014), we conceived that the number of books at home, referred to as the home literacy score by IEA, can be an index of scholarly culture of the student's home, and its aggregated average constitutes scholarly culture of the classrooms/schools. The results obtained through multilevel analysis indicated that there were indeed large unique compositional effects and its effect size was comparable to that of mean parent education, individual level scholarly culture, and parent education. Implications of the results in terms of educational policy were discussed. 相似文献
10.
Innovative Higher Education - Universities across the U.S. have increasingly emphasized internationalization, leading to rising numbers of international students attending U.S. institutions of... 相似文献