Maximal lactate steady state in trained adolescent runners

The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake ([Vdot]O₂). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0?mmol?·?l^?1 were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5?km?·?h^?1, where the change in blood lactate concentration between 10 and 20?min was?<0.5?mmol?·?l^?1. Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3?km?·?h^?1, P?<0.01), once the data were expressed relative to percent peak [Vdot]O₂ (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P?>0.05). The running speed and percent peak [Vdot]O₂ at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5?mmol?·?l^?1 (P?>0.05), but were both lower than those at the 4.0?mmol?·?l^?1 concentration (P?<0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak [Vdot]O₂ and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5?mmol?·?l^?1 measured during an incremental treadmill test in boys and girls.     

A protocol for measuring the direct effect of cycling on neuromuscular control of running in triathletes

Abstract

The direct effects of cycling on movement and muscle recruitment patterns (neuromuscular control) during running are unknown but critical to success in triathlon. We outline and test a new protocol for investigating the direct influence of cycling on neuromuscular control during running. Leg movement (three-dimensional kinematics) and muscle recruitment (surface electromyography, EMG) were compared between a control run (no prior exercise) and a 30-min transition run that was preceded by 20 min of cycling. We conducted three experiments investigating: (a) the repeatability (between-day reliability) of the protocol; (b) the ability of the protocol to investigate, in highly trained national or international triathletes, the direct influence of cycling on neuromuscular control during running independent of neuromuscular fatigue; and (c) the ability of the protocol to provide a control, or baseline, measure of neuromuscular control (determined using a measure of stability) without causing fatigue. Kinematic and EMG measures of neuromuscular control during running showed moderate to high repeatability: mean coefficients of multiple correlation for repeatability of EMG and kinematics were 0.816 ± 0.014 and 0.911 ± 0.031, respectively. The protocol provided a robust baseline measure of neuromuscular control during running without causing neuromuscular fatigue (coefficients of multiple correlation for stability of EMG and kinematics were 0.827 ± 0.023 and 0.862 ± 0.054), while EMG and force data provided no evidence of fatigue. The protocol outlined here is repeatable and can be used to measure any direct influence of cycling on neuromuscular control during running.     

What's in It for Me? Incentives,Learning, and Completion in Massive Open Online Courses

This study investigated the distribution of incentives (e.g., certificates, badges) for massive open online course (MOOC) completion, and relationships between incentives and MOOC outcomes. Participants were 779 MOOC students internationally who participated in at least 303 different MOOCs offered by at least 12 providers. MOOC participants most commonly intended to receive, and in actuality received, free and paid course certificates of completion; other incentives (e.g., digital badges, postsecondary credits) were far less common. In addition, MOOC participants' intentions to receive both free and paid certificates were consistently and positively related to perceived learning and course completion, net other factors. (Keywords: massive open online courses, MOOCs, motivation, incentives, microcredentials, certificates of completion)     

Conceptualizing climate change in the context of a climate system: implications for climate and environmental education

Today there is much interest in teaching secondary students about climate change. Much of this effort has focused directly on students’ understanding of climate change. We hypothesize, however, that in order for students to understand climate change they must first understand climate as a system and how changes to this system due to both natural and human influences result in climatic and environmental changes and feedbacks. The purpose of this article is to articulate a climate system framework for teaching about climate change and to stimulate discussion about what secondary students should know and understand about a climate system. We first provide an overview of the research on secondary students’ conceptions of climate and climate change. We then present a climate system framework for teaching about climate and climate change that builds on students’ conceptions and scientific perspectives. We conclude by articulating a draft conceptual progression based on students’ conceptions and our climate system framework as a means to inform curriculum development, instructional design, and future research in climate and environmental education.     

Anatomical Sciences Education Vol. 5, Issue 3, 2012 Cover Image

Medical students at the Schulich School of Medicine and Dentistry at The University of Western Ontario in London, Ontario, Canada, learn clinical facts about the hepatobiliary system as transplant surgeon Dr. Vivian McAlister (at the far right) demonstrates Whipple's procedure in the anatomy laboratory. In this issue of ASE, Ullah and colleagues describe an extracurricular student initiative known as the Surgically Oriented Anatomy Program (SOAP), which aims to deliver anatomy teaching from a surgical perspective through the philosophy of “education through recreation”.     

Reducing Children's Implicit Racial Bias Through Exposure to Positive Out‐Group Exemplars

Studies with adults suggest that implicit preferences favoring White versus Black individuals can be reduced through exposure to positive Black exemplars. However, it remains unclear whether developmental differences exist in the capacity for these biases to be changed. This study included 369 children and examined whether their implicit racial bias would be reduced following exposure to positive Black exemplars. Results showed that children's implicit pro‐White bias was reduced following exposure to positive Black exemplars, but only for older children (M_age = ~10 years). Younger children's (M_age = ~7 years) implicit bias was not affected by this intervention. These results suggest developmental differences in the malleability of implicit racial biases and point to possible age differences in intervention effectiveness.     

How Does It Look? Level 2 Perspective‐Taking at 36 Months of Age

Previous research has found that children engage in Level 2 visual perspective-taking, that is, the understanding that others may see things in a different way, between 4 and 5 years of age (e.g., J. H. Flavell, B. A. Everett, K. Croft, & E. R. Flavell, 1981). This ability was reexamined in 36-month-olds using color filters. In Experiment 1 (N = 24), children had to recognize how an object looked to an adult when she saw it through a color filter. In Experiment 2 (N = 24), a novel production test was applied. Results of both studies show that 36-month-olds know how an object looks to another person. The discussion focuses on the psychological requirements of visual perspective-taking and its relation to other "theory of mind" abilities, such as the distinction between appearance and reality and understanding false belief.     

Synthesizing the Indexing and Propaganda Models: An Evaluation of US News Coverage of the Uprising in Ecuador,January 2000

This is a study of US-based print media coverage of the indigenous-led uprising in Ecuador which occurred in January 2000. As a result of having mobilized tens of thousands of Ecuadorans, the Confederation of Indigenous Nationalities of Ecuador managed to peacefully force the resignation of a President who had presided over one of the worst recessions in Ecuador's modern history. Nevertheless, most US news dailies covered the affair as if it was purely a military coup and a threat to democracy, in spite of the existence of hundreds of citizen-led, participatory governing councils (called the “People's Parliament,” by Ecuadorans). Previous scholarship on media performance in relation to US foreign policy has proven in a variety of cases to serve as a useful analytical tool and predictive device. This article evaluates the extent that the propaganda model by Edward S. Herman and Noam Chomsky, as well as the indexing model by W. Lance Bennett, are instructive in the case of the news media performance of US which covered the uprising in Ecuador.     

Introduction to the special issue on teaching and learning in information retrieval

We present an overview of the special issue in this paper. The main objective is to provide information for lecturers on how to improve the student experience, using current knowledge in the field. To this end we present an overview of six papers covering areas as diverse as tools and methods used to support teaching and learning, pedagogical challenges in teaching mathematics for search, etc.     

Relative shank to thigh length is associated with different mechanisms of power production during elite male ergometer rowing

The effect of anthropometric differences in shank to thigh length ratio upon timing and magnitude of joint power production during the drive phase of the rowing stroke was investigated in 14 elite male rowers. Rowers were tested on the RowPerfect ergometer which was instrumented at the handle and foot stretcher to measure force generation, and a nine segment inverse dynamics model used to calculate the rower's joint and overall power production. Rowers were divided into two groups according to relative shank thigh ratio. Time to half lumbar power generation was significantly earlier in shorter shank rowers (p = 0.028) compared to longer shank rowers, who showed no lumbar power generation during the same period of the drive phase. Rowers with a relatively shorter shank demonstrated earlier lumbar power generation during the drive phase resulting from restricted rotation of the pelvic segment requiring increased lumbar extension in these rowers. Earlier lumbar power generation and extension did not appear to directly affect performance measures of the short shank group, and so can be attributed to a technical adaptation developed to maximise rowing performance.