Longitudinal changes in submaximal oxygen uptake in 11- to 13-year-olds

The aim of this study was to monitor longitudinal changes in young people's submaximal oxygen uptake (VO 2 ) responses during horizontal treadmill running at 8 km h -1 . The 236 participants (118 boys, 118 girls) were aged 11.2 +/- 0.4 years (mean +/- s) at the onset of the study. Submaximal VO 2 , peak VO 2 and anthropometry were recorded annually for three consecutive years. The data were analysed using multi-level regression modelling within a multiplicative, allometric framework. The initial model examined sex, age and maturity-related changes in submaximal VO 2 relative to body mass as the sole anthropometric covariate. Our results demonstrate that the conventional ratio standard ml kg -1 min -1 does not adequately describe the true relationship between body mass and submaximal VO 2 during this period of growth. The effects of maturity and age were non-significant, but girls consumed significantly less VO 2 than boys running at 8 km h -1 . In subsequent models, stature was shown to be a significant explanatory variable, but this effect became non-significant when the sum of two skinfolds was added. Thus, within this population, submaximal VO 2 responses were explained predominantly by changes in body mass and skinfold thicknesses, with no additional maturity-related increments. When differences in body mass and skinfolds were controlled for, there was still a difference between the sexes in submaximal VO 2 , with girls becoming increasingly more economical with age.     

The effects of carbohydrate ingestion on the badminton serve after fatiguing exercise

Abstract

The badminton serve requires great skill and may be affected by fatigue. The aim of the present study was to determine whether carbohydrate ingestion affects badminton performance. Nine male badminton players (age 25 ± 7 years, mass 80.6 ± 8.0 kg) attended the laboratory on three occasions. The first visit involved an incremental exercise test to exhaustion to determine peak heart rate. Participants were given 1 L of a carbohydrate-electrolyte drink or a matched placebo during the experimental trials. The accuracy of 10 long and 10 short serves was determined before and after exercise. The fatiguing exercise was 33 min in duration (83 ± 10% and 84 ± 8% peak heart rate for the placebo and carbohydrate trial respectively). Capillary blood samples (20 μL) were taken before and after exercise for determination of blood glucose and lactate. There was deterioration in long serve accuracy with fatigue (P = 0.002), which carbohydrate ingestion had a tendency to prevent (P = 0.077). There was no effect of fatigue (P = 0.402) or carbohydrate ingestion (P = 0.109) on short serve accuracy. There was no difference in blood glucose concentration between trials (P = 0.851). Blood lactate concentration was higher during the placebo trial (P = 0.016). These results suggest that only the long serve is influenced by fatigue and carbohydrate had a tendency to prevent the deterioration in performance.     

Physiological demands of downhill mountain biking

Abstract

Mountain biking is a popular recreational pursuit and the physiological demands of cross-country style riding have been well documented. However, little is known regarding the growing discipline of gravity-assisted downhill cycling. We characterised the physiological demands of downhill mountain biking under typical riding conditions. Riding oxygen consumption ([Vdot]O₂) and heart rate (HR) were measured on 11 male and eight female experienced downhill cyclists and compared with data during a standardised incremental to maximum ([Vdot]O_2max) exercise test. The mean [Vdot]O₂ while riding was 23.1 ± 6.9 ml · kg^?1 · min^?1 or 52 ± 14% of [Vdot]O_2max with corresponding heart rates of 146 ± 11 bpm (80 ± 6% HRmax). Over 65% of the ride was in a zone at or above an intensity level associated with improvements in health-related fitness. However, the participants’ heart rates and ratings of perceived exertion were artificially inflated in comparison with the actual metabolic demands of the downhill ride. Substantial muscular fatigue was evident in grip strength, which decreased 5.4 ± 9.4 kg (5.5 ± 11.2%, P = 0.03) post-ride. Participation in downhill mountain biking is associated with significant physiological demands, which are in a range associated with beneficial effects on health-related fitness.     

Development of the Physical Education Observation Instrument Using Generalizability Study Theory

In this exploratory study, the rater reliability of the Physical Education Observation Instrument (PEOI) was satisfactorily established. Three raters coded the frequency of occurrences of selective teacher (9) and student (4) behaviors and one catchall category when male teachers were instructing male pupils in volleyball. A 3 Rater × 3 Teacher × 2 Occasion Generalizability Study design indicated high stability of both inter- and intra-rater scores on 13 of 14 variables from ě_p ² .65 to .99, establishing the appropriateness of the PEOI for further observational research on teacher and student behaviors in physical education.     

Personality and its Relationship to Success in Professional Baseball

Purpose: The relationships among students' self-efficacy, 2 × 2 achievement goals (mastery-approach [MAp], mastery-avoidance [MAv], performance-approach [PAp], and performance-avoidance goals), and achievement performance remain largely unanswered. We tested a model of the mediating role of self-efficacy on the relationship between 2 × 2 achievement goals and cardiorespiratory fitness. Method: A sample of 276 middle school students (115 boys and 161 girls; 91 sixth graders, 87 seventh graders, and 98 eighth graders), aged 12 to 15 years (M _age = 13.34, SD = 0.96), responded to the Achievement Goals Questionnaire (Conroy, Elliot, &; Hofer, 2003) and Self-Efficacy Questionnaire (Gao, Newton, &; Carson, 2008) referenced to the fitness test. Their cardiorespiratory fitness was assessed via the Progressive Aerobic Cardiorespiratory Endurance Run (PACER) 3 days later. Results: Structural equation modeling demonstrated an acceptable model fit to the data, χ ² (2, N = 105) = 1.66. Self-efficacy had a statistically significant direct effect on the PACER after controlling for the effects of the achievement goals (γ _{self-efficacy-PACER}  = .21). MAv and PAp also had direct effects on PACER performance (γ _MAv-PACER  = ? .24, and γ _PAp-PACER  = .24, respectively). MAp failed to exert direct effect on the PACER. However, the indirect effect of MAp on the PACER via self-efficacy was small although it was statistically significant. Additionally, the indirect effects of MAv and PAp on PACER through self-efficacy were not significant. Conclusions: Students' self-efficacy fully mediated the effect of MAp on fitness performance, as well as partially mediated the effects of MAv and PAp on cardiorespiratory fitness performance. Study implications are provided for educators and practitioners.     

Global Status, Intra-Institutional Stratification and Organizational Segmentation: A Time-Dynamic Tobit Analysis of ARWU Position Among U.S. Universities

Ranking systems such as The Times Higher Education’s World University Rankings and Shanghai Jiao Tong University’s Academic Rankings of World Universities simultaneously mark global status and stimulate global academic competition. As international ranking systems have become more prominent, researchers have begun to examine whether global rankings are creating increased inequality within and between universities. Using a panel Tobit regression analysis, this study assesses the extent to which markers of inter-institutional stratification and organizational segmentation predict global status among US research universities as measured by position in ARWU. Findings indicate some support that both inter-institutional stratification and organizational segmentation predict global status.     

It takes two to tango: knowledge mobilization and ignorance mobilization in science research and innovation

The main goal of this paper is to propose a dynamic mapping for knowledge and ignorance mobilization in science research and innovation. An underlying argument is that ‘knowledge mobilization’ science policy agendas in countries such as Canada and the United Kingdom fail to capture a critical element of science and innovation: ignorance mobilization. The latter draws attention to dynamics upstream of knowledge in science research and innovation. Although perhaps less visible, there is ample evidence that researchers value, actively produce, and thereby mobilize ignorance. For example, scientists and policymakers routinely mobilize knowledge gaps (cf. ignorance) in the process of establishing and securing research funding to argue the relevance of a scientific paper or a presentation, and to launch new research projects. Ignorance here is non-pejorative and by and large points to the borders and the limits of scientific knowing – what is known to be unknown. In addition, processes leading to the intentional or unintentional consideration or bracketing out of what is known to be unknown are intertwined with, yet remain distinct from, knowledge mobilization dynamics. The concepts of knowledge mobilization and of ignorance mobilization, respectively, are understood to be the use of knowledge or ignorance towards the achievement of goals. The value of this paper lies in its conceptualization of the mobilization of knowledge as related to the mobilization of ignorance within a complex, dynamic and symbiotic relationship in science research and innovation: it takes two to tango.     

“I Need You to Show Me:” Coaching Early Childhood Professionals

Early Childhood Education Journal - In most states, Early Childhood Educators (ECEs) with a Birth-Kindergarten teaching license serve as both the general education teacher and special education...     

Parental Perspectives on Children’s School Readiness: An Ethnographic Study

Early Childhood Education Journal - School readiness is a construct used by educators and policy makers to describe a range of abilities that are beneficial for children transitioning to school....