Reply to Glazier: “Comment on ‘Influence of shaft length on golf driving performance’”

Abstract

In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty‐four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three‐dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.     

Promotion of self-regulated learning in classrooms: investigating frequency, quality, and consequences for student performance

An implication of the current research on self-regulation is to implement the promotion of self-regulated learning in schools. Teachers can promote self-regulated learning either directly by teaching learning strategies or indirectly by arranging a learning environment that enables students to practise self-regulation. This study investigates teachers’ direct and indirect promotion of self-regulated learning and its relation to the development of students’ performance. Twenty German mathematics teachers with their overall 538 students (grade 9) were videotaped for a three-lesson unit on the Pythagorean Theorem. Students’ mathematics performance was tested several times before and after the observed lessons. A low-inferent coding system was applied to assess the teachers’ implicit or explicit instruction of cognitive strategies (e.g., organisation), metacognitive strategies (e.g., planning), and motivational strategies (e.g., resource management). High-inferent ratings were used to assess features of the learning environment that foster self-regulation. Results reveal that a great amount of strategy teaching takes place in an implicit way, whereas explicit strategy teaching and supportive learning environment are rare. The instruction of organisation strategies and some features of the learning environment (constructivism, transfer) relate positively to students’ performance development. In contrast to implicit strategy instruction, explicit strategy instruction was associated with a gain in performance. These results reveal a discrepancy between the usefulness of explicit strategy instruction and its rare occurrence in classrooms.     

Development of a measurement and feedback training tool for the arm strokes of high-performance luge athletes

Previous studies have shown that the start plays a critical role in sliding events and explains more than 55% of the variance of the final time in luge. Experts evaluate the contribution of the arm strokes to be 23% of the total starting performance. The aim of the present study was to develop a measurement and feedback training tool (Speedpaddler) for the arm strokes of high-performance luge athletes. The construction is an aluminium alloy framework with a customary belt conveyor system, which is driven by two synchronized servo motors. Training is possible with constant speeds up to 12 m · s(-1) or several speed curves, which simulate the acceleration of different luge tracks. The construction facilitates variations in the inclination and speed of the conveyor belts and thereby the resistance and movement speed. If the athlete accelerates the conveyor belts during arm-paddling, the torque of the motors decreases. Torque measurements and high-speed video offer valuable insights into the several technique criteria. Comparisons of arm-paddle cycle durations on ice and on the Speedpaddler with 18 luge athletes (national team and juniors) showed no statistical differences. The Speedpaddler might be a useful tool to improve starting performance all year round.     

The validity of estimating triceps brachii volume from single MRI cross-sectional area before and after resistance training

The aim of this study was to determine whether triceps brachii muscle volume can be adequately estimated from a single anatomical cross-sectional area (ACSA) and can the same model be used for prediction after training. Thirty-five healthy male non-athletes (age 21.6 ± 2.5 years, body mass index 24.8 ± 3.5 kg · m(-2)) volunteered for this study. The volumes of the upper arm extensors were calculated from magnetic resonance imaging (MRI) sequence scans and regression models were developed, which were used to predict muscle volumes from single MRI cross-sectional scans taken at different points along the humerus length. The same procedure was repeated after 12 weeks of maximal resistance training of the elbow extensors. Correlation coefficients were calculated for Model A with CSA(max), humerus length (HL), and body mass index (r = 0.919), a model with CSA(50%) and HL (r = 0.922), and a model with CSA(60%) and HL (r = 0.920) (P < 0.001). The standard error of estimate for Model A, Model CSA(50%), and Model CSA(60%) was 8.0%, 7.7%, and 7.8% respectively. Thesame prediction formula can be used for the left arm (r = 0.904). If a single ACSA is used for triceps brachii volume prediction, the best fit is with Model CSA(60%) and HL, both before and after training (r = 0.941). By introducing humerus length into the calculation, we simplify the procedure for volume measurement, since it can be obtained during MRI scanning.     

Auf der Suche nach Verkettungen in Entity-Relationship-Schemata

Zusammenfassung. Redundante Komponenten in Entity-Relationship-Schemata führen zu Speicherverschwendung und Fehlern bei der Nutzung der aus dem Schema gewonnenen Datenbanken. Zwischen Schemaredundanz und dem Konzept der ableitbaren Komponenten besteht eine enge Verbindung, denn redundante Schemakomponenten sind stets ableitbar. Andererseits ist nicht jede ableitbare Komponente auch redundant. Es wird deshalb zun?chst das Verh?ltnis zwischen redundanten und ableitbaren Komponenten diskutiert und eine Klassifizierung eingeführt, welche die Modellierer bef?higt, entbehrliche von nicht entbehrlichen Komponenten zu unterscheiden. Eine spezielle Art ableitbarer Komponenten, die Verkettung von Beziehungsarten, wird anschlie?end mit allen ihren Erscheinungsformen vorgestellt. Au?erdem werden Methoden diskutiert, die helfen k?nnen, Verkettungen aufzudecken. Eingegangen am 30. Mai 1996 / Angenommen am 8. April 1997     

The metabolic cost of two ranges of arm position height with and without hand weights during low impact aerobic dance.

To determine the energy cost of low impact aerobic dance while varying arm movement height and the use of hand weights, 10 adults volunteered to participate in four choreographed trials. All trials consisted of identical leg movements. Arm movements, however, were performed above shoulder level both with and without 0.9-kg hand weights and below shoulder level both with and without 0.9-kg hand weights. Open circuit spirometry was employed throughout the 10-min videotape guided trials, and heart rate was measured by telemetry. Neither the use of hand weights nor the change in arm position height significantly altered the energy cost of low impact aerobic dance. However, heart rate responses were significantly different. Caution should be observed by aerobics instructors and participants as to the use of heart rate as an indicator of intensity for low impact aerobic dance.     

Discovering the More: Reading Wright's,Colette's,and Cather's Texts as Philosophy of Education

Rather than using literary texts to evidence an analytic argument, within this piece we read Julia McNair Wright's (US, 1840–1902), Sidonie-Gabrielle Colette's (France, 1873–1954), and Willa Cather's (US, 1873–1947) texts through theoretical lenses that expose their educational meaning and value and that create conversation among them concerning girls’ and women's educations. While we do not claim that one can generalize these women's works and lessons to every life, we contend that these women and the literary products they created offer girls and women powerful lessons about resistance, subversion, and nurturing one's intellect, lessons that in some ways transcend class and race in particular. First, we define and explain Bruner's concept of the more using Rosenblatt, Gallagher, and Gardner's theories and findings to illuminate his concept. Next, we identify and examine three themes that emerge across these authors’ texts—subverting through the everyday, becoming one's own steward, and moving from survival to self-actualization. Establishing these themes first in Wright's texts, we then use them to frame Colette's and Cather's fiction and support these themes by focusing on one lesson that emerges from each author's work(s). Finally, we ask what one might learn about educating girls and women from these texts and others whose educative meaning and value remain hidden.     

Administrative rhetoric: An undemocratic response to protest

Much of the criticism of protest rhetoric has centered on the protestors themselves. This essay focuses on administrators, particularly those at the University of California at Berkeley, and the rhetoric they used in response to protest. It outlines the major lines of argument that administrators traditionally use.