The influence of ventilatory control on heart rate variability in children

The aim of this study was to determine the influence of breathing frequency and tidal volume on resting heart rate variability in children aged 9 years (n = 29) and 16 years (n = 19). Heart rate variability was measured in four conditions: (1) without the control of ventilation followed at random by (2) a fixed breathing frequency of 12 breaths x min(-1), (3) a breathing frequency of 12 breaths x min(-1) but with a fixed tidal volume of 30% vital capacity and (4) a fixed breathing frequency of 6 breaths x min(-1) and a tidal volume of 30% vital capacity. A total of 128 RR intervals (the time between two spikes in the heart rate) were detected and absolute high- and low-frequency spectral components were calculated using autoregressive modelling. The younger children were unable to control ventilation to achieve conditions 3 and 4; therefore, a 2 x 2 (group x condition) analysis of variance was used to analyse conditions 1 and 2. There were significant interactions between group and heart rate variability conditions for the low-frequency component and the ratio of low to high frequencies (P < 0.001). The main effect for condition showed that at 12 breaths x min(-1) with no fixed tidal volume there was a significantly higher standard deviation of the RR interval, total power and high-frequency (P< 0.01) and low-frequency spectral components (P < 0.05) than in the condition with no ventilatory control. Across the four breathing conditions for the older participants, the high-frequency spectral component was significantly higher in the condition at 6 breaths x min(-1) with a fixed tidal volume than in that with no ventilatory control (P < 0.005); the ratio of high to low frequencies was significantly lower for the spontaneous condition than those performed at 12 breaths x min(-1) (P < 0.001). The results provide evidence of the need for ventilatory control when assessing short-term resting heart rate variability in children.     

Imagery use in elite youth sport participants: reinforcing the applied significance of achievement goal theory

This study examined the motivational profiles of elite youth athletes to determine whether individual differences in goal orientation corresponded with differential levels of imagery use. Two hundred ninety male (n = 88) and female (n = 202) young athletes (M = 16.6 years, SD = 1.48) completed the Perceptions of Success Questionnaire (POSQ, Roberts, Treasure, & Balague, 1998) to assess dispositional goal orientations and the Sport Imagery Questionnaire (Hall, Mack, Paivio, & Hausenblas, 1998) to assess frequency and function of imagery use. A two-stage cluster analysis on the POSQ scores revealed a three-cluster solution with a multivariate analysis of variance indicating significant differences among cluster groups in imagery use. Athletes in Cluster 3 (higher task/higher ego) used significantly more imagery, regardless of the function than athletes in Cluster 1 (lower task/moderate ego) or Cluster 2 (moderate task/lower ego). These findings are discussed with reference to the role of achievement motivation in influencing young athletes' behavioral investments in mental strategies.     

Tool for Assessing Responsibility-Based Education (TARE): Instrument Development,Content Validity,and Inter-Rater Reliability

Numerous scholars have stressed the importance of personal and social responsibility in physical activity settings; however, there is a lack of instrumentation to study the implementation of responsibility-based teaching strategies. The development, content validity, and initial inter-rater reliability testing of the Tool for Assessing Responsibility-Based Education (TARE) are described here. Inter-rater agreement was calculated for paired observations focused on 2 different teachers delivering a total of 18 separate physical education lessons for students in grades 1 through 6. Findings indicate that the Tool for Assessing Responsibility-Based Education provides scores with adequate inter-rater reliability. The procedures employed in this study proved feasible and enable observers to characterize the implementation of responsibility-based teaching in physical education. The Tool for Assessing Responsibility-Based Education has numerous research and training applications relative to the Teaching Personal and Social Responsibility model (Hellison, 2003 Hellison, D. 2003. Teaching responsibility through physical activity, 2nd, 15–38. Champaign, IL: Human Kinetics.  [Google Scholar]) and the national content standards for K–12 physical education, specifically Standard 5: Exhibits responsible personal and social behavior that respects self and others in physical activity settings (National Association for Sport and Physical Education, 2004 National Association for Sport and Physical Education (NASPE). 2004. Moving into the future. National standards for physical education, 2nd, 39–43. Reston, VA: Author.  [Google Scholar]).     

Playing surface and UK professional rugby union injury risk

Artificial rugby union playing surface installation is increasing. This prospective cohort study aimed to examine the effect of playing surface on match injury types within 157 players of two UK professional rugby union clubs playing 209 matches (96 on artificial surfaces and 113 on grass) over three seasons. There was no difference in overall injury risk between the two playing surfaces with injury incidence on artificial 80.2 (CI 69.9–91.7) and on grass 81.9 per 1000 match-hours (CI 72.2–92.5), with an incidence rate ratio (RR) of 0.98 (CI 0.82–1.17). There was a higher rate of concussion (RR 0.52, CI 0.34 – 0.78) and chest injuries on grass (RR 0.26 CI 0.07, 0.95), and a higher rate of thigh haematoma (RR 2.25, CI 1.05–4.82) foot injuries (RR 4.12, CI 1.10, 15.40) and injury to players being tackled (RR 1.46, CI 1.00, 2.15) on artificial. Whilst there was no higher injury risk for matches played on artificial versus natural grass surfaces, the higher incidence of concussion and chest injury on grass, and the higher rate of foot injuries on artificial surfaces may be related to tackle and footwear-to-surface interface factors.     

Language and reading impairments are associated with increased prevalence of non-right-handedness

Handedness has been studied for association with language-related disorders because of its link with language hemispheric dominance. No clear pattern has emerged, possibly because of small samples, publication bias, and heterogeneous criteria across studies. Non-right-handedness (NRH) frequency was assessed in N = 2503 cases with reading and/or language impairment and N = 4316 sex-matched controls identified from 10 distinct cohorts (age range 6–19 years old; European ethnicity) using a priori set criteria. A meta-analysis (N_cases = 1994) showed elevated NRH % in individuals with language/reading impairment compared with controls (OR = 1.21, CI = 1.06–1.39, p = .01). The association between reading/language impairments and NRH could result from shared pathways underlying brain lateralization, handedness, and cognitive functions.     

The long-term athlete development model: physiological evidence and application

Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence.     

Carnosine in health and disease

Abstract

Carnosine was originally discovered in skeletal muscle, where it exists in larger amounts than in other tissues. The majority of research into the physiological roles of carnosine have been conducted on skeletal muscle. Given this and the potential for muscle carnosine content to be increased with supplementation, there is now a large body of research examining the ergogenic effects (or otherwise) of carnosine. More recent research, however, points towards a potential for carnosine to exert a wider range of physiological effects in other tissues, including the brain, heart, pancreas, kidney and cancer cells. Taken together, this is suggestive of a potential for carnosine to have therapeutic benefits in health and disease, although this is by no means without complication. Herein, we will provide a review of the current literature relating to the potential therapeutic effects of carnosine in health and disease.     

The Effect of Newspaper Coverage of Influenza on the Rate of Physician Visits for Influenza 2002–2008

The effect that newspapers had on patients visiting physicians for influenza was examined for 2002 to 2008. The basis for this investigation rests on theories of media effects drawn from agenda setting, media hype, and the Social Amplification of Risk Framework. It was hypothesized that controlling for the rate of influenza, a positive relationship exists in which increases and decreases of newspaper attention to influenza precede increases and decreases in the percentage of patients visiting physicians for flu symptoms. The percentage of visits and the percentage of positive flu tests are taken from the Centers for Disease Control's flu report. Media attention was located through the Lexis/Nexis database as words per week in stories having flu in the headline in 32 newspapers. Time series analysis shows that controlling for autoregressive and seasonal effects, and the actual rate of disease present, news attention in the previous week accounts for a statistically significant portion of the increase and decrease in the number of individuals who go to their physician reporting influenza-like symptoms. Reverse causality was examined. It was shown that controlling for autoregressive and seasonal effects, patient visits did not predict news coverage, whereas the rate of the flu in the previous 3 weeks did.