Athens 2004: the pollution climate and athletic performance

Athens sits in a basin approximately 450 km² in area, surrounded by mountains and open sea. Anthropogenic emissions in conjunction with the topographical and meteorological conditions can result in high air pollution within the city. The pollutants of concern for athletes competing in Athens 2004 appear to be nitrogen dioxide (NO₂), ozone and particulate (PM₁₀) pollution. Exposure to elevated ozone concentrations has been reported to give rise to symptoms that include cough, chest pain, difficulty in breathing, headache, eye irritation and a decrease in forced expiratory volume in one second. All of these effects are likely to impact upon performance, and several studies of cyclists suggest this to be the case. In contrast, the impact of ambient concentrations of NO₂ appears to be negligible on normal activities, but at high exercise intensities the impact remains unclear. The use of currently available information and models to predict the effect of ozone and other pollutants on elite athletes is problematical, since such models are based upon significantly lower ventilation rates than those achieved by some elite athletes. In addition, it is already known that the response to ozone can vary somewhat between individuals. Since the individuals who will be competing in Athens are physiologically very different to the participants in most published studies, it is difficult to predict individual responses. There is some evidence to indicate that adaptation to the adverse health and performance effects of ozone can occur, so that performance is partially recovered on re-exposure. The adaptation is not seen in all studies and appears to be dependent on several factors, including the initial sensitivity of the individual to ozone. Antioxidant supplementation has also been shown in some studies to partially ameliorate the adverse effects of ozone by counteracting the oxidative stress mechanism associated with this pollutant. Whether this transfers to performance enhancement per se remains unclear at present. Additional research is required to gain a sound understanding of the effects of a complex mixed air pollution exposure on the pulmonary function and performance of athletes exercising at high work intensities.     

Relationships between cardiorespiratory fitness,inhibition, and math fluency: A cluster analysis

ABSTRACT

This study identified clusters of adolescents who share similar cardiorespiratory fitness levels and analysed the relationships between cardiorespiratory fitness, inhibition, and math fluency in each of the clusters. The subjects were 490 high-school students aged 10–16 years. The mean age was 13.82 years (SD = 1.12). Latent class analysis identified three clusters with high, medium, and low levels of cardiorespiratory fitness. The high-fitness cluster achieved higher scores in inhibition and math fluency than the low-fitness cluster. Path analysis revealed that the influence of cardiorespiratory fitness on inhibition was non-existent in the three clusters. The effect of inhibition on math fluency was positive and significant in all three cardiorespiratory fitness levels. Cardiorespiratory fitness had a direct, positive, and significant effect on math fluency only in the high-fitness cluster. Therefore, a high level of cardiorespiratory fitness is a significant determining factor in the explanation of math fluency. These results indicate that inhibition does not mediate the relationship between cardiorespiratory fitness and math fluency. However, the benefits of cardiorespiratory fitness affect math fluency, which has important implications for the educational environment and the teaching/learning process.     

Threshold frequency of an electrically induced cramp increases following a repeated,localized fatiguing exercise

Abstract

Though clinical observations and laboratory data provide some support for the neuromuscular imbalance theory of the genesis of exercise-associated muscle cramps, no direct evidence has been published. The purpose of this study was to determine the effect of local muscle fatigue on the threshold frequency of an electrically induced muscle cramp. To determine baseline threshold frequency, a cramp was electrically induced in the flexor hallucis brevis of 16 apparently healthy participants (7 males, 9 females; age 25.1 ± 4.8 years). The testing order of control and fatigue conditions was counterbalanced. In the control condition, participants rested in a supine position for 30 min followed by another cramp induction to determine post-threshold frequency. In the fatigue condition, participants performed five bouts of great toe curls at 60% one-repetition maximum to failure with 1 min rest between bouts followed immediately by a post-threshold frequency measurement. Repeated-measures analysis of variance and simple main effects testing showed post-fatigue threshold frequency (32.9 ± 11.7 Hz) was greater (P < 0.001) than pre-fatigue threshold frequency (20.0 ± 7.7 Hz). An increase in threshold frequency seems to demonstrate a decrease in one's propensity to cramp following the fatigue exercise regimen used. These results contradict the proposed theory that suggests cramp propensity should increase following fatigue. However, differences in laboratory versus clinical fatiguing exercise and contributions from other sources, as well as the notion of a graded response to fatiguing exercise, on exercise-associated muscle cramp and electrically induced muscle cramp should be considered.     

Uncovering young children's motivational beliefs about learning science

Young children, ages 5–6 years, develop first beliefs about science and themselves as science learners, and these beliefs are considered important precursors of children's future motivation to pursue science. Yet, due to a lack of adequate measures, little is known about young children's motivational beliefs about learning science. The present two‐part study explores the motivational beliefs of young children using a new measure—the Young Children's Science Motivation (Y‐CSM) scale. Initial measurement development involved a thorough literature review of existing measures, and an extensive piloting phase until a final instrument was reached. To establish scale reliability, measurement invariance as well construct and criterion validity, the final instrument was administered to a new sample of 277 young children, age 5–6 years, in northern Germany. Results reveal that children's motivational beliefs can be empirically differentiated into their self‐confidence and enjoyment in science at this young age. Older children were more motivated in science, but no significant gender differences were found. Importantly, children in preschools with a science focus reported significantly higher science motivation. This finding stresses the importance of early science education for the development of children's motivational beliefs science.     

Individual differences in the self-image of adolescents with learning disabilities: the roles of severity, time of diagnosis, and parental perceptions.

The self-images of 49 adolescents with learning disabilities (Grades 9 through 12, mean age = 15.9) and 49 normally achieving peers (Grades 9 through 12, mean age = 16.0) were compared using the Offer Self-Image Questionnaire (OSIQ). The group with LD scored significantly lower than the comparison group on 4 of the 10 OSIQ scales. Later-diagnosed adolescents with LD scored significantly higher than early-diagnosed adolescents on two of the scales. Severity of the learning disability was not found to be related to self-image scores. In a second study, parental perceptions of the self-images of 28 of the 49 students with LD were studied by administering the Offer Parent-Adolescent Questionnaire (OPAQ) and an informal questionnaire to their parents. On 6 of the 10 OPAQ scales, parents perceived their children as having a lower self-image than the adolescents themselves reported. Significant but moderate relationships were found between parents' perceptions and adolescent self-image scores. Results of the two studies are interpreted in terms of a multidimensional conception of self-image that considers factors inherent to the individual as well as interpersonal and institutional factors.     

For children only? Effects of the KiVa antibullying program on teachers

The effects of an antibullying program, KiVa, on Grade 1–3 teachers' perceptions of bullying were investigated. Data were gathered from 128 teachers in 33 intervention schools and 110 teachers in 29 control schools. Two-level regression models showed that, at the end of the intervention year, self-evaluated competence to tackle bullying was at a higher level in the intervention schools than in the control schools. In addition, in the intervention schools, participation in KiVa activities was associated with teacher perceptions of bullying. The need to take teacher and organization perspectives into consideration in future whole-school intervention studies is discussed.     

International Communications

Church, Communication, Development (Committee on Society, Development, and Peace; Publications Department; Ecumenical Centre, 150 Route de Ferney, 1211 Geneva 20, Switzerland, $3.50)

Ithiel de Sola Pool, Philip Stone and Alexander Szalai's Communications, Computers and Automation for Development (UNITAR Research Reports No. 6, UNITAR, 801 United Nations Plaza, New York 10017, $2.00)

George Melly's Revolt into Style: the Pop Arts in Britain (Penguin [hardback], $8.95)

T.C. Worsley's Television: The Ephemeral Art (London: Alan Ross, $9.00)

D.G. Bridson's Prospero and Ariel: The Rise and Fall of Radio—A Personal Recollection (London: Gollancz, $10.50)

Raymond Durgnat's A Mirror for England: British Movies from Austerity to Affluence (Praeger, $11.95)

Asa Briggs History of Broadcasting in the United Kingdom (Oxford University Press, 1961, 1965)