Effect of swimming velocity on arm coordination in the front crawl: a dynamic analysis

We examined the preferred mode of arm coordination in 14 elite male front-crawl swimmers. Each swimmer performed eight successive swim trials in which target velocity increased from the swimmer's usual 3000-m velocity to his maximal velocity. Actual swim velocity, stroke rate, stroke length and the different arm stroke phases were then calculated from video analysis. Arm coordination was quantified by an index of coordination based on the lag time between the propulsive phases of each arm. The index expressed the three coordination modes in the front crawl: opposition, catch-up and superposition. First, in line with the dynamic approach to movement coordination, the index of coordination could be considered as an order parameter that qualitatively captured arm coordination. Second, two coordination modes were observed: a catch-up pattern (index of coordination= -8.43%) consisting of a lag time between the propulsive phases of each arm, and a relative opposition pattern (index of coordination= 0.89%) in which the propulsive phase of one arm ended when the propulsive phase of the other arm began. An abrupt change in the coordination pattern occurred at the critical velocity of 1.8 m. s(-1), which corresponded to the 100-m pace: the swimmers switched from catch-up to relative opposition. This change in coordination resulted in a reorganization of the arm phases: the duration of the entry and catch phase decreased, while the duration of the pull and push phases increased in relation to the whole stroke. Third, these changes were coupled to increased stroke rate and decreased stroke length, indicating that stroke rate, stroke length, the stroke rate/stroke length ratio, as well as velocity, could be considered as control parameters. The control parameters can be manipulated to facilitate the emergence of specific coordination modes, which is highly relevant to training and learning. By adjusting the control and order parameters within the context of a specific race distance, both coach and swimmer will be able to detect the best adapted pattern for a given race pace and follow how arm coordination changes over the course of training.     

Three waves of gay male athlete coming out narratives

Recent announcements by Michael Sam, Jason Collins, Robbie Rogers, and others belong to a longer tradition that I label the gay male athlete coming out narrative. I chart this rhetorical genre in three waves, corresponding to the historical moment in which each narrative was published and the rhetorical tactics that each set of authors use to reconcile their identities as gay athletes and argue for the existence and suitability of gay men in professional sports. Of particular note are contemporary third-wave narratives which introduce the actively out, visible, gay male body becoming aware of his place in history as a rhetorical opportunity for social intervention. Even as I recognize the limits of athletes’ ability to represent the diversity of interests, values, and politics of the broader LGBTQ movement, I argue that these narratives should become part of what Charles E. Morris III calls “the diverse domain of the usable past.” These narratives indicate the importance of understanding genre evolution alongside individual biography, historical context, and shifting values within broader attempts at social transformation.     

Immersive Audio Storytelling: Podcasting and Serial Documentary in the Digital Publishing Industry

Structural shifts behind the rise of podcasting have led to programming aimed at sustaining audience attention, a development coinciding with the sharp increase in engaged time with digital longform content among mobile users. This study industrially and culturally situates 3 case studies: True Murder (a pioneering precursor to This American Life producers’ Serial), S-Town (Serial’s successor that far exceeded its listenership), and Ear Hustle (Radiotopia’s experiment in subject-produced content made by two inmates at San Quentin State Prison). Each case illustrates how distinct sectors of the podcasting industry approach the production of absorbing nonfiction through transparent journalism featuring self-reflexive metanarrative.     

Did the Gamemakers Fix the Lottery in the Hunger Games?

The Hunger Games is an annual event in the fictional country of Panem. Each year, 24 children (tributes) are chosen by lottery from 12 districts to fight to the death in the arena for the entertainment of the Capitol citizens. Using statistical analysis and computer simulations, we will explore the possibility that the Gamemakers, those in charge of planning the Hunger Games, fixed the lottery. Using the fictitious data from Suzanne Collins' book the Hunger Games, we show how students can learn how to perform a permutation goodness of fit test.     

Intensity-dependent reductions in resting blood pressure following short-term isometric exercise training

To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMG_peak (~23%MVC, maximum voluntary contraction, or 30%EMG_peak (~34%MVC)] or control group; 3 weeks of IET at 30%EMG_peak resulted in significant reductions in resting mean arterial pressure (e.g. ?3.9 ± 1.0 mmHg, P < 0.001), whereas 20%EMG_peak did not (?2.3 ± 2.9 mmHg; P > 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMG_peak and 30%EMG_peak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible.     

Student Use of Scaffolding Software: Relationships with Motivation and Conceptual Understanding

This study was designed to theoretically articulate and empirically assess the role of computer scaffolds. In this project, several examples of educational software were developed to scaffold the learning of students performing high level cognitive activities. The software used in this study, Artemis, focused on scaffolding the learning of students as they performed information seeking activities. As 5th grade students traveled through a project-based science unit on photosynthesis, researchers used a pre-post design to test for both student motivation and student conceptual understanding of photosynthesis. To measure both variables, a motivation survey and three methods of concept map analysis were used. The student use of the scaffolding features was determined using a database that tracked students’ movement between scaffolding tools. The gain scores of each dependent variable was then correlated to the students’ feature use (time and hits) embedded in the Artemis Interface. This provided the researchers with significant relationships between the scaffolding features represented in the software and student motivation and conceptual understanding of photosynthesis. There were a total of three significant correlations in comparing the scaffolding use by hits (clicked on) with the dependent variables and only one significant correlation when comparing the scaffold use in time. The first significant correlation (r = .499, p < .05) was between the saving/viewing features hits and the students’ task value. This correlation supports the assumption that there is a positive relationship between the student use of the saving/viewing features and the students’ perception of how interesting, how important, and how useful the task is. The second significant correlation (r = 0.553, p < 0.01) was between the searching features hits and the students’ self-efficacy for learning and performance. This correlation supports the assumption that there is a positive relationship between the student use of the searching features and the students’ perception of their ability to accomplish a task as well as their confidence in their skills to perform that task. The third significant correlation (r = 0.519, p < 0.05) was between the collaborative features hits and the students’ essay performance scores. This correlation supports the assumption that there is a positive relationship between the student use of the collaborative features and the students’ ability to perform high cognitive tasks. Finally, the last significant correlation (r = 0.576, p < 0.01) was between the maintenance features time and the qualitative analysis of the concept maps. This correlation supports the assumption that there is a positive relationship between the student use of the maintenance features and student conceptual understanding of photosynthesis. This material is based upon work supported by the National Science Foundation (REC9980055). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.