Comment on ‘Ventilation and blood lactate increase exponentially during incremental exercise’ : A reply

Oar force and oar angle data resulting from a 6‐min maximal rowing ergometer test undertaken by novice (n = 9), good (n ‐ 23) and national (n = 9) level male rowers, were used to identify biomechanical performance variables which accurately discriminated between rowers of differing ability levels. The variables included two work capacity measures, mean propulsive power output per kilogram of body mass (W kg^‐1) and propulsive work consistency (%), and two skill variables, stroke‐to‐stroke consistency (%) and stroke smoothness (%). Discriminant function analysis indicated the presence of two functions, both of which clearly indicated the importance of mean propulsive power output per kilogram of body mass as a discriminating variable. Function 2 gave greater weight to stroke‐to‐stroke consistency and stroke smoothness than function 1; however, function 1 was the most powerful discriminator. Classification procedures were used to predict the ability level to which a rower most likely belonged and involved defining the ‘distance’ between each rower and each ability level centroid, with the rower being classified into the ‘nearest’ ability level. These procedures indicated that 100% of the elite, 73.9% of the good, 88.9% of the novice and 82.9% of all rowers were correctly classified into their respective skill levels. Stepwise discriminant analysis included the variables in the following order: mean propulsive power output per kilogram of body mass, stroke‐to‐stroke consistency, stroke smoothness and propulsive work consistency (P < 0.001). The results of this study indicate that biomechanical performance variables related to rowing capacity and skill may be identified and used to discriminate accurately between rowers of differing skill levels, and that, of these variables, propulsive work consistency is the least effective discriminator.     

Distribution of Practice in Motor Skill Acquisition: Different Effects for Discrete and Continuous Tasks

Abstract

Research on the benefits of distributed practice for the acquisition and retention of motor skills has a long history. The majority of this research has involved skill acquisition of continuous tasks. However, there is some evidence to suggest that distribution of practice effects are quite different for discrete tasks than for continuous tasks. In the present study, we used a single task, formed discrete and continuous versions of the task, and examined how acquisition and retention were affected by the length of inter-trial interval. The basic task was a movement timing task that involved either one timing estimate per trial (the “discrete” version) or twenty successive estimates per trial (the “continuous” version). Separate groups of subjects learned one version of the task under either distributed (25 s inter-trial intervals) or massed (0.5 s inter-trial intervals) practice conditions. Both massed and distributed retention trials were performed on the same version of the task according to a double transfer design. The results confirmed the apparent disparity: Acquisition and retention were facilitated by distributed practice on the continuous task, but by massed practice on the discrete task. These results were discussed in terms of the role of the inter-trial interval in discrete and continuous tasks.     

Influence of regression model and initial intensity of an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and running performance

Abstract

This study investigated the influence of the regression model and initial intensity during an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and performance in elite-standard runners. Twenty-three well-trained runners completed a discontinuous incremental running test on a treadmill. Speed started at 9 km · h^?1 and increased by 1.5 km · h^?1 every 4 min until exhaustion, with a minute of recovery for blood collection. Lactate–speed data were fitted by exponential and polynomial models. The lactate threshold was determined for both models, using all the co-ordinates, excluding the first and excluding the first and second points. The exponential lactate threshold was greater than the polynomial equivalent in any co-ordinate condition (P < 0.001). For both models, the lactate threshold was lower when all co-ordinates were used than when the first and the first and second points were excluded (P < 0.001). 10-km race pace was correlated with both the exponential and polynomial lactate thresholds for all the co-ordinate conditions (r ≥ 0.75, P < 0.001 and r ≥ 0.56, P < 0.05, respectively). The results suggest that the exponential lactate threshold should be used instead of the polynomial equivalent since it is more strongly associated with performance and is independent of the initial intensity of the test.     

Physiological Effects of Deep Water Running following a Land-Based Training Program

Abstract

The purpose of this study was to examine differences in knowledge representation and problem solutions in expert and novice youth baseball players. Ninety-four players in two age divisions, 7–8 years of age and 9–10 years of age, were assigned to three levels of expertise: high; average; and low skilled. Each subject participated in an interview session to elicit knowledge representation and solutions to five different defensive game situations. Interviews were transcribed and analyzed for content, solution to the problem, errors in problem solution, and qualitative trends. The frequency of advanced solutions to each of the five situations were analyzed in separate chi-square tests for age and expertise. Differences among the levels of expertise were found for the accuracy of solutions to three complex situations. Age was significant for only one situation. Patterns of knowledge content accessed during advanced and less advanced responses indicated both experts and novices were in a beginning stage of developing baseball knowledge structures. Errors in problem solutions indicated children had difficulty monitoring critical conditions and making correct inferences. Players' and teammates' ability to execute baseball skills seemed to influence the content and structure of tactical knowledge accessed during problem solution.     

Fitting Structural Equation Model Trees and Latent Growth Curve Mixture Models in Longitudinal Designs: The Influence of Model Misspecification

When conducting longitudinal research, the investigation of between-individual differences in patterns of within-individual change can provide important insights. In this article, we use simulation methods to investigate the performance of a model-based exploratory data mining technique—structural equation model trees (SEM trees; Brandmaier, Oertzen, McArdle, & Lindenberger, 2013)—as a tool for detecting population heterogeneity. We use a latent-change score model as a data generation model and manipulate the precision of the information provided by a covariate about the true latent profile as well as other factors, including sample size, under the possible influences of model misspecifications. Simulation results show that, compared with latent growth curve mixture models, SEM trees might be very sensitive to model misspecification in estimating the number of classes. This can be attributed to the lower statistical power in identifying classes, resulting from smaller differences of parameters prescribed by the template model between classes.     

‘I’m just not that comfortable with technology’: student perceptions of and preferences for Web 2.0 technologies in reflective journals

Encouraging reflective practice and developing reflective practitioners is a goal of many disciplines in higher education. A variety of pedagogical techniques have been used to promote critical reflection including portfolios, narratives and reflective journals. Over the past decade, the use of Web 2.0 technologies with students has been increasingly adopted in higher education settings and many educators have integrated these technologies into reflective assignments. These educators assume that students, who are members of the Net Generation, are technologically savvy and have the ability to integrate the use of Web 2.0 technologies into learning. However, while there have been studies examining the outputs of reflective assignments using Web 2.0 technologies such as blogs, e-portfolios and wikis, there has been little research examining whether or not students actually use technology for these types of assignment if given the choice. Therefore, the purpose of this study was to explore if technology was appropriated or rejected by students for a reflective journaling assignment. Results are based on a content analysis of 42 student journaling assignments and interviews with eight students. Findings suggest that (1) students are not as technologically competent as assumed; (2) students chose to use basic/fundamental technologies (e.g. word processing) because they viewed it as the easiest way to complete the reflective journaling assignment; (3) student perceptions of what makes an assignment ‘good’ influenced their choice to use Web 2.0 technologies; and (4) overarching student perceptions of higher education and learning impacted their appropriation of technology. Implications are discussed and recommendations for both research and practice are made.     

Boy Trouble: Rhetorical framing of boys' underachievement

This article examines discourse in the United States used to socially construct an “underachieving boys” moral panic. Employing discourse analysis I examine the adversarial rhetoric of claims-makers and the frames they deploy to undermine alternative and conflicting accounts (of females as disadvantaged) and to forestall any challenges to the scientific authority of their own (biological essentialist) account of crisis. I illustrate how this discourse adapts the rhetorical frame of gender equity from the discourse it politically opposes, and uses it to legitimate its own goals. I find that the framing of innocent victimized boys as scientific “truth” is aligned with a broader masculinity politics that blames certain “folk devils”, and a synchronic moral panic about fearsome (black) male youth. I conclude by considering the success of this moral panic as evidenced by changes in educational policies and practices in the United States.     

The Community of Practice among Mathematics and Mathematics Education Faculty Members at an Urban Minority Serving Institution in the U.S.

Using narrative inquiry as a research method, four mathematics and mathematics education faculty members explored the integration of theoretical perspectives into their personal narratives as they developed a community of practice. Initially their focus was strictly on improving their students’ mathematical knowledge. As their community of practice matured, however, their work took on a larger meaning as they contributed to the institution’s strategic goal of raising the annual dollar amount of external funding and to the development of their personal and collective identities. This unusual level of inter-departmental collaboration has been recognized by the institution’s highest administrators, who have called upon its members to develop new, collaborative partnerships with regional school districts and community colleges.     

彰显独特十法则

你认为自己是独一无二的吗？世上每一个人都是独特的,都拥有区别于别人的特点。让我们把自己的独特完全释放,给别人一个完全不同的自己。     

Factors that influence university students’ intention to use Moodle: a study in Macau

Educational technology research and development - Moodle is widely used in higher education institutions in this digital age. With the growing popularity of Moodle use in education, this study...