Influence of vitamin D mushroom powder supplementation on exercise-induced muscle damage in vitamin D insufficient high school athletes

Abstract

Incidence of vitamin D deficiency is increasing worldwide. The purpose of this study was to determine if supplementation with vitamin D₂ from Portobello mushroom powder would enhance skeletal muscle function and attenuate exercise-induced muscle damage in low vitamin D status high school athletes. Participants were randomised to Portobello mushroom powder (600 IU/d vitamin D₂) or placebo for 6 weeks. Participants then completed a 1.5-h exercise session designed to induce skeletal muscle damage. Blood samples and measures of skeletal muscle function were taken pre-supplementation, post-supplementation/pre-exercise and post-exercise. Six weeks supplementation with vitamin D₂ increased serum 25(OH)D₂ by 9.9-fold and decreased serum 25(OH)D₃ by 28%. Changes in skeletal muscle function and circulating markers of skeletal muscle damage did not differ between groups. In conclusion, 600 IU/d vitamin D₂ increased 25(OH)D₂ with a concomitant decrease in 25(OD)D₃, with no effect on muscular function or exercise-induced muscle damage in high school athletes.     

Handling pressures: analysing touch in American films about youth sport

This paper examines how films produced in the USA in the past 10 years and featuring the coaching of youth sport, represent the issue of touch during instruction and training. Touch in such films is figured in diverse ways ranging from pats of reassurance and hugs of congratulation to cuffs of disapprobation. Touch is also occasionally depicted differently, dependent upon the ethnicity and gender of the central characters in specific films. These distinctions are evaluated for what they reveal about the nuances of understandings of touch in film portrayals of sport education in American high schools. The difficulty of interpreting physical contact between coaches and athletes in these films, and what this reveals about the problem of policing touch in general in educational settings, is explored. Finally, the paper examines how the films expose the intricacy of tactile encounters in ways that challenge the judiciousness of risk-averse ‘no-touch’ policies and practices in sports coaching.     

A Tutorial on Centering in Cross-Sectional Two-Level Models

The primary purpose of this tutorial is to succinctly review some options for, and consequences of, centering Level 1 predictors in commonly applied cross-sectional two-level models. It is geared toward both practitioners and researchers. A general understanding of multilevel modeling is necessary prior to understanding the subtleties of centering decisions. A review of some high-quality journals within the broad discipline of exercise science provides evidence that multilevel modeling is used relatively infrequently in this field. Therefore, a secondary purpose is to introduce Measurement in Physical Education and Exercise Science readers to some core facets of multilevel modeling within the framework of this tutorial. A relevant dataset is used to demonstrate potential consequences of different centering decisions within a multilevel model. Depending on the model and the data, different centering decisions can exert non-trivial influence on the meaning of some model parameters, results from fitting the model, and subsequent conclusions.     

Effect of the coefficient of friction of a running surface on sprint time in a sled-towing exercise

This study investigated the effect of the coefficient of friction of a running surface on an athlete's sprint time in a sled-towing exercise. The coefficients of friction of four common sports surfaces (a synthetic athletics track, a natural grass rugby pitch, a 3G football pitch, and an artificial grass hockey pitch) were determined from the force required to tow a weighted sled across the surface. Timing gates were then used to measure the 30-m sprint time for six rugby players when towing a sled of varied weight across the surfaces. There were substantial differences between the coefficients of friction for the four surfaces (μ = 0.21–0.58), and in the sled-towing exercise the athlete's 30-m sprint time increased linearly with increasing sled weight. The hockey pitch (which had the lowest coefficient of friction) produced a substantially lower rate of increase in 30-m sprint time, but there were no significant differences between the other surfaces. The results indicate that although an athlete's sprint time in a sled-towing exercise is affected by the coefficient of friction of the surface, the relationship relationship between the athlete's rate of increase in 30-m sprint time and the coefficient of friction is more complex than expected.     

Associations between peer bullying and classroom concentration: evidence for mediation by perceived personal safety and relationship with teacher

Being bullied is associated with a psycho-social maladjustment during childhood. One hitherto largely overlooked correlate is disrupted classroom concentration. Using data collected from 364 9–11-year-old children attending seven junior schools in the UK, we tested a model in which children’s perceived safety in two contexts (classroom and playground) and their perceived relationship with their teacher were hypothesised to mediate the association between being bullied and classroom concentration. Two analytical approaches to testing multiple mediation – product of coefficients and bootstrapping – supported the model. None of the mediation effects was moderated by sex but they were by year; in all cases the mediation effect was stronger in the older children than in the younger children (but still significant among the latter). These data suggest mechanisms through which bullying might have its effects on classroom concentration. The practical and theoretical implications are discussed.     

Who benefits from student aid? The economic incidence of tax-based federal student aid

Federal benefit programs, including federal student aid, are designed to aid targeted populations. Behavioral responses to these programs may alter the incidence of their benefits, a possibility that receives less attention in the literature compared to tax incidence. I demonstrate the importance of benefit incidence analysis by showing that the intended cost reductions of tax-based federal student aid are substantially offset by institutional price increases for a sample of 4-year colleges and universities. Contrary to the goal of policymakers, I find that tax-based aid crowds out institutional aid roughly dollar-for-dollar. Unfortunately, it is not clear how institutions utilize these captured resources, so that the ultimate incidence of the programs is uncertain.     

The United Kingdom Children’s Laureate: The Story So Far

Britain’s Children’s Laureate Scheme has now been running for 14 years. This article asks Quentin Blake, Anne Fine, Michael Morpurgo, Jacqueline Wilson, Anthony Browne, Michael Rosen and Julia Donaldson for their views on their own experience of taking up this post. It concludes with a discussion of the recurring issues raised by these Laureates along with a look at possible future developments.     

Veteran Ally: Practical Strategies for Closing the Military-Civilian Gap on Campus

Since the Post-9/11 GI Bill was enacted in 2009, student veteran populations have nearly doubled while services that support their transition to higher education have dramatically increased. Despite a surge in resources, however, institutions are deficient in training faculty and staff about veterans’ issues, consequently leaving student veterans susceptible to inaccurate perceptions about their service and wellbeing. In an effort to provide an inclusive environment for service members, this article discusses findings from two focus groups and 14 interviews with student veterans. Recommendations for training faculty and staff and enhancing the visibility of veterans’ issues through Veteran Ally training and student veteran discussion panels are discussed.     

NEW TECHNOLOGIES

THE COMMUNITY MEDIUM, edited by Nancy Jesuale with Ralph Lee Smith (182 pages)

A GUIDE FOR LOCAL POLICY, edited by Nancy Jesuale with Richard M. Neustadt and Nicholas P. Miller (131 pages)

Jane Wilson, “New Information Technologies for the Nonprofit Sector,” (The Foundation Center, 888 Seventh Ave., New York, N.Y. 10106---$4.95, paper)

1982 CABLE ADVERTISING DIRECTORY (Nations Cable Television Association, 1724 Massachuse Avenue, N.W., Washington, D.C. 20036---$30. paper)

THE INTERACTIVE CABLE TV HANDBOOK (Phillips Publishing , 7315 Wisconsin Avenue, Suite 1200 N, Bethesda, MD 20814---$49.00, paper)

COUNTDOWN: DIRECT-TO-HOME SATELLITE BROADCASTING IN THE EIGHTIES (65 pages---$75.00, paper)

VIDEODISC: BOOM OR BUST? THE STORY OF THE VIDEODISC IN 1981 FROM THE PAGES OF TELEVISION DIGEST (75 pages, $75.00, paper)