Muscle cross-sectional areas and performance power of limbs and trunk in the rowing motion

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.     

Relationship between Achilles tendon properties and foot strike patterns in long-distance runners

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.     

Students’ understanding of the structure of deductive proof

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.     

Is changing teaching practice the mission impossible? A case study of continuing professional development for primary school teachers in Senegal

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.     

Delayed intermodal contingency affects young children's recognition of their current self

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.     

Multilevel analysis of student civics knowledge scores

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 Evans, M. D. R., Kelley, J., Sikora, J., &; Treiman, D. J. (2010). Family scholarly culture and educational success: Books and schooling in 27 nations. Research in Social Stratification and Mobility, 28, 171–197.[Crossref], [Web of Science ®] , [Google Scholar], 2014 Evans, M. D. R., Kelley, J., &; Sikora, J. (2014). Scholarly culture and academic performance in 42 nations. Social Forces, 92, 1573–1605.[Crossref], [Web of Science ®] , [Google Scholar]), 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.     

Help me help myself: examining an electronic mental health self-monitoring system in college students

Higher Education - The high prevalence of mental illness in college students results in adverse consequences that have led to developing prevention programs, with the potential of self-monitoring...     

Levels of Proof in Lower Secondary School Mathematics

The purpose of this study is to establish levels from an inductive proof to an algebraic demonstration in lower secondary school mathematics. I propose that we can establish six levels of proof in lower secondary school mathematics as steps from an inductive proof to an algebraic demonstration on the basis of three axes (contents of proof, representation of proof, and students' thinking). To reach this conclusion, I firstly examine the meaning of demonstration in lower secondary school mathematics and proof in lower secondary school mathematics, and show the relationships between them. Secondly, I set out four basic levels of proof, as seen from two aspects (contents and representation of proof). Thirdly, I subdivide them into six levels from the third aspect of students' thinking. Finally, I illustrate my discussion with a 7th grader's activities.This revised version was published online in September 2005 with corrections to the Cover Date.     

Kinetics of throwing arm joints and the trunk motion during an overarm distance throw by skilled Japanese elementary school boys

The purpose of this study was to investigate joint kinetics of the throwing arms and role of trunk motion in skilled elementary school boys during an overarm distance throw. Throwing motions of 42 boys from second, fourth, and sixth grade were videotaped with three high-speed cameras operating at 300 fps. Seven skilled boys from each grade were selected on the basis of throwing distance for three-dimensional kinetic analysis. Joint forces, torques, and torque powers of the throwing arm joints were calculated from reconstructed three-dimensional coordinate data smoothed at cut-off frequencies of 10.5–15 Hz and by the inverse dynamics method. Throwing distance and ball velocity significantly increased with school grade. The angular velocity of elbow extension before ball release increased with school grade, although no significant increase between the grades was observed in peak extension torque of elbow joint. The joint torque power of shoulder internal/external rotation tended to increase with school grade. When teaching the overarm throw, elementary school teachers should observe large backward twisting of trunk during the striding phase and should keep in mind that young children, such as second graders (age 8 years), will be unable to effectively utilise shoulder external/internal rotation during the throwing phase.     

Active muscle and tendon stiffness of plantar flexors in sprinters

The aim of the present study was to investigate and compare muscle and tendon stiffness under active conditions in sprinters and untrained participants. In total, 14 sprinters and 24 untrained men participated in this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated based on changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Tendon stiffness was determined during isometric plantar flexion using ultrasonography. No significant differences were observed in active muscle stiffness between sprinters and untrained men at any torque levels. Furthermore, no significant difference was noted in tendon stiffness between the two groups. These results suggest that muscle and tendon mechanical properties in the plantar flexors under active conditions are similar in sprinters and untrained participants.