Dietary supplements

For the athlete training hard, nutritional supplements are often seen as promoting adaptations to training, allowing more consistent and intensive training by promoting recovery between training sessions, reducing interruptions to training because of illness or injury, and enhancing competitive performance. Surveys show that the prevalence of supplement use is widespread among sportsmen and women, but the use of few of these products is supported by a sound research base and some may even be harmful to the athlete. Special sports foods, including energy bars and sports drinks, have a real role to play, and some protein supplements and meal replacements may also be useful in some circumstances. Where there is a demonstrated deficiency of an essential nutrient, an increased intake from food or from supplementation may help, but many athletes ignore the need for caution in supplement use and take supplements in doses that are not necessary or may even be harmful. Some supplements do offer the prospect of improved performance; these include creatine, caffeine, bicarbonate and, perhaps, a very few others. There is no evidence that prohormones such as androstenedione are effective in enhancing muscle mass or strength, and these prohormones may result in negative health consequences, as well as positive drug tests. Contamination of supplements that may cause an athlete to fail a doping test is widespread.     

Body sway,aim point fluctuation and performance in rifle shooters: inter- and intra-individual analysis

In this study, we examined the relationships between body sway, aim point fluctuation and performance in rifle shooting on an inter- and intra-individual basis. Six elite shooters performed 20 shots under competition conditions. For each shot, body sway parameters and four aim point fluctuation parameters were quantified for the time periods 5 s to shot, 3 s to shot and 1 s to shot. Three parameters were used to indicate performance. An AMTI LG6-4 force plate was used to measure body sway parameters, while a SCATT shooting analysis system was used to measure aim point fluctuation and shooting performance. Multiple regression analysis indicated that body sway was related to performance for four shooters. Also, body sway was related to aim point fluctuation for all shooters. These relationships were specific to the individual, with the strength of association, parameters of importance and time period of importance different for different shooters. Correlation analysis of significant regressions indicated that, as body sway increased, performance decreased and aim point fluctuation increased for most relationships. We conclude that body sway and aim point fluctuation are important in elite rifle shooting and performance errors are highly individual-specific at this standard. Individual analysis should be a priority when examining elite sports performance.     

Golf science research at the beginning of the twenty-first century

At the beginning of the twenty-first century, there are 30,000 golf courses and 55 million people who play golf worldwide. In the USA alone, the value of golf club memberships sold in the 1990s was US dollar 3.2 billion. Underpinning this significant human activity is a wide variety of people researching and applying science to sustain and develop the game. The 11 golf science disciplines recognized by the World Scientific Congress of Golf have reported 311 papers at four world congresses since 1990. Additionally, scientific papers have been published in discipline-specific peer-reviewed journals, research has been sponsored by the two governing bodies of golf, the Royal and Ancient Golf Club of St. Andrews and the United States Golf Association, and confidential research is undertaken by commercial companies, especially equipment manufacturers. This paper reviews much of this human endeavour and points the way forward for future research into golf.     

一个亟需重视的问题——保护好中学生的嗓音

优美悦耳的歌喉,对于从事各种音乐、话剧、戏曲、电影、电视等文艺工作者来说,是非常珍贵的。然而,却很少有人想到中学生嗓音保护的问题。请看:——     

EEG analysis of children with attention-deficit/hyperactivity disorder and comorbid reading disabilities

This study investigated electroencephalographic differences between two groups of children with attention-deficit/hyperactivity disorder, combined type, with reading disabilities (ADHD + RD) or without (ADHD) and typical control participants. Twenty participants were included in each group. All participants were between the ages of 8 and 12 years, and groups were matched on age and gender. The electroencephalographic (EEG) was recorded during an eyes-closed resting condition from 21 monopolar derivations, which were clustered into nine regions for analysis. The EEGs were Fourier-transformed to provide absolute and relative power estimates for the delta, theta, alpha, and beta bands. Ratio coefficients were also calculated for the theta/alpha and theta/beta ratios. Compared with controls, the clinical groups demonstrated the increased slow-wave and reduced fast-wave activity commonly reported in the ADHD literature. The ADHD + RD group had more relative theta, less relative alpha, and a higher theta/alpha ratio than the ADHD group. A number of hemispheric differences were also found in the delta and alpha bands. These results suggested that some of the EEG divergences found in the ADHD + RD group represent an electrophysiological component associated with the reading disability that is independent of the EEG divergences found in ADHD.     

Remembering as discrimination in delayed matching to sample: Discriminability and bias

Task difficulty in delayed matching-to-sample tasks (DMTS) is increased by increasing the length of a retention interval. When tasks become more difficult, choice behavior becomes more susceptible to bias produced by unequal reinforcer ratios. Delaying reinforcement from choice behavior also increases both task difficulty and the biasing effect of unequal reinforcer probability. Six pigeons completed nine DMTS conditions with retention intervals of 0, 2, 4, 6, and 8 sec, in which reinforcer delays of 0, 2, and 4 sec were combined with ratios of reinforcer probabilities of .5/.5, .2/.8, and .8/.2 for correct red and green responses. Discriminability (logd) decreased with both increasing retention interval duration and increasing reinforcer delay. Sensitivity to reinforcement, the tendency for ratios of choice responses to follow unequal reinforcer probabilities, also increased as a function of both increasing retention interval and increasing reinforcer delay. The result is consistent with the view that remembering in DMTS tasks is a discriminated operant in which increasing task difficulty increases sensitivity to reinforcement.     

Elevated picture completion scores: a possible indicator of hypervigilance in maltreated preschoolers

OBJECTIVE: The Picture Completion subtest of the Wechsler Preschool and Primary Scales of Intelligence-Revised (WPPSI-R) measures visual alertness and the ability to differentiate essential from nonessential details. In children who are hypervigilant as a result of maltreatment, these skills may be over-functioning. It was hypothesized that the Picture Completion subtest scores of these children would be significantly elevated in comparison to their other nonverbal scores and their overall intellectual functioning. METHOD: Fourteen children from a therapeutic day treatment preschool program for maltreated children were administered the WPPSI-R. Standardized discrepancy scores between Picture Completion scores and Performance mean scores (PC-Performance Discrepancy) and the mean of all subscale scores (PC-Overall IQ Discrepancy) were formed and then analyzed. RESULTS: The abused preschoolers scored significantly lower than the population mean on four of the five WPPSI-R Performance subscales. Only on Picture Completion did they score significantly higher. Average PC-Performance Discrepancy and PC-Overall IQ Discrepancy scores were greater than one, indicating that the mean difference of children's Picture Completion score from either their Performance mean score or all of their mean scores was more than one standard deviation. CONCLUSION: Elevated Picture Completion score may serve as a marker for hypervigilance and/or PTSD in children with histories of maltreatment.     

Making instruction and assessment responsive to diverse students' progress: group-administered dynamic assessment in teaching mathematics

This study entailed a 3 (instructional intervention) × 2 (assessment-type) between-subjects experimental design employing a pretest-intervention-posttest methodology. The instructional interventions were administered between subjects in three conditions: (a) dynamic instruction, (b) triarchic or theory of successful intelligence-control instruction, and (c) standard-control instruction. The assessment-type consisted between subjects of either (a) a group-administered dynamic posttest or (b) the same group-administered posttest interspersed with a control filler activity. Performance in different mathematics content areas taught in fourth grade was investigated. In total, 1,332 students and 63 classroom teachers in 24 schools across six school districts participated in the study. The results indicate the advantages of using dynamic instruction and assessment in regular classrooms while teaching mathematics, especially when the student body is highly ethnically diverse.