Quantification of the Relative Age Effect in Three Indices of Physical Performance

The relative age effect (RAE) describes the relationship between an individual's birth month and their level of attainment in sports. There is a clustering of birth dates just after the cutoff used for selection in age-grouped sports, and it is hypothesized that such relatively older sportspeople may enjoy maturational and physical advantages over their younger peers. There is, however, little empirical evidence of any such advantage. This study investigated whether schoolchildren's physical performance differed according to which quarter of the school year they were born in. Mass, stature, body mass index, cardiorespiratory fitness, strength, and power were measured in 10 to 16 year olds (n = 8,550, 53% male). We expressed test performance as ageand sex-specific z-scores based on reference data with age rounded down to the nearest whole year and also as units normalized for body mass. We then compared these values between yearly birth quarters. There were no significant main effects for differences in anthropometric measures in either sex. Girls born in the first quarter of the school year were significantly stronger than those born at other times when handgrip was expressed as a zscore. As z-scores, all measures were significantly higher in boys born in either the first or second yearly quarters. Relative to body mass, cardiorespiratory fitness was higher in boys born in the first quarter and power was higher in those born in the second quarter. The RAE does not appear to significantly affect girls' performance test scores when they are expressed as z-score or relative to body mass. Boys born in the first and second quarters of the year had a significant physical advantage over their relatively younger peers. These findings have practical bearing if coaches use fitness tests for talent identification and team selection. Categorizing test performance based on rounded down values of whole-year age may disadvantage children born later in the selection year. These relatively younger children may be less to gain selection for teams or training programmes. © 2013 National Strength and Conditioning Association

Epidemiology of screen time, sleep habits, physical activity and their association with non-invasive cardiometabolic risk factors in English schoolchildren

Background: The preventable risk factors for cardiovascular diseases (CVD) and diabetes cluster together and can be tracked from childhood into adulthood. There is evidence that sleep, cardiorespiratory fitness and socioeconomic status (SES) are related to the component risk factors of cardiometabolic syndrome, but this is mainly in adults. Current interventions to prevent cardiometabolic syndrome, also, are not robust enough and multisectoral approaches are still lacking in preventing these preventable risk factors. The aim of this thesis is to evaluate prevalence, identify some of the causes of these risk factors, their social determinants and how they are associated with another in English schoolchildren. Setting: Field·based research including schoolchildren from the East of England, United Kingdom. Methods: Cross~section of English state schoolchildren between lO~16 years participating in the East of England Healthy Hearts study. Height, weight and blood pressure (BP) measured by stadiometer, weighing scales and automated BP monitors using standard procedures respectively. Cardiorespiratory fitness assessed by the 20m shuttle~run test. Demographic data, screen time, sleep & wake time and physical activity (P A) levels were measured using questionnaires. Schoolchildren level of deprivation was measured using English Index of Multiple Deprivation. Metabolic risk profiles were categorised based on weight status and SBP status. Findings: Overall, 36% of schoolchildren were exposed to over 2 hours of daily screen time. Those reportiIlg 4h (OR 2.26, 95%CI 1.91 - 2.67). Prevalence of elevated mean arterial pressure (MPJl) was 14.8% overall but rose to 35.7% in those who were both obese and unfit. When compared with schoolchildren engaging in PA daily with adults in their household, schoolchildren who have reported no PA daily with adults in their household were likely (OR 1.54, 95%CI 1.07-2.20) to have an elevated MR profile. Rural children were more active than those from urban areas, but this was not evident when a trilateral division was used. About 40% of schoolchildren go to bed late at night. Late bedtime was associated with deprivation in schoolchildren. Compared to those with 4 hours of daily screen time (OR 1.97, 95%CI 1.34-2.89). Interpretations: Sedentary behaviour, parental influences, cardiorespiratory fitness, place and location of habitation are associated with the causes of CVD and component factors of cardiometabolic syndrome in schoolchildren. There was a high prevalence of>2h daily screen time in English schoolchildren. PA is lower in children reporting 2-4h versus 4h) independent of deprivation, Increasing cardiorespiratory fitness level may have a positive impact on the weight-related elevations of MAP seen in obese and overweight schoolchildren. Joint PA with an adult within household could increase schoolchildren's cardiorespiratory fitness level, PA level and may reduce the risk of metabolic diseases. Rural environments support PA in children but not PA of adole scents, Town and fringe areas with mixed elements of rural and urban land use appear to fac ilitate and sustain PA in both children and adolescents, High screen time 2 , j and deprivation may explain lateness in bedtime in English schoolchildren. Family centred interventions may be important to reduce screen time and improve metabolic profile .EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Screen time and passive school travel as independent predictors of cardiorespiratory fitness in youth

Objective: The most prevalent sedentary behaviours in children and adolescents are engagement with small screen media (screen-time) and passive travel (by motorised vehicle). The objective of this research was to assess the independence of these behaviours from one another and from physical activity as predictors of cardiorespiratory fitness in youth. Methods: We measured cardiorespiratory fitness in n = 6819 10-16. year olds (53% male) who self-reported their physical activity (7-day recall) school travel and screen time habits. Travel was classified as active (walking, cycling) or passive; screen time as 4 h. Results: The multivariate odds of being fit were higher in active travel (Boys: OR 1.32, 95% CI: 1.09-1.59; Girls: OR 1.46, 1.15-1.84) than in passive travel groups. Boys reporting low screen time were more likely to be fit than those reporting > 4 h (OR 2.11, 95% CI: 1.68-2.63) as were girls (OR 1.66, 95% CI: 1.24-2.20). These odds remained significant after additionally controlling for physical activity. Conclusion: Passive travel and high screen time are independently associated with poor cardiorespiratory fitness in youth, and this relationship is independent of physical activity levels. A lifestyle involving high screen time and habitual passive school travel appears incompatible with healthful levels of cardiorespiratory fitness in youth. © 2012 Elsevier Inc

Recreational Cycling and Cardiorespiratory Fitness in English Youth

PURPOSE: Schoolchildren who cycle to school have higher cardiorespiratory fitness (CRF) than those who are driven or use public transport. The purpose of this study was to determine whether recreational cycling is similarly associated with CRF. METHODS: Participants were 5578 (54% males) English schoolchildren (10.0-15.9 yr). All reported frequency of recreational cycling events via 7-d recall. Responses were categorized as follows: "noncyclists" = 0, "occasional cyclists" = 1-4, or "regular cyclists" = 5+ (times per week). CRF was assessed using the 20-m shuttle run test with performance classified as "fit" or "unfit" based on FITNESSGRAM standards. RESULTS: Overall, 26% of males and 46% of females were noncyclists. Compared with noncyclists, the 40% of males and 42% of females classified as occasional cyclists were more likely to be fit (males: odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.07-1.59; females: OR = 1.41, 95% CI = 1.13-1.76). Regular cyclists (34% males and 12% females) had a greater likelihood still of being classified as fit (males: OR = 1.58, 95% CI = 1.29-1.95; females: OR = 1.55, 95% CI = 1.09-2.20). No odds remained significant after adjusting for physical activity. Removal of participants who cycled to school had little overall effect on the likelihood of being classified as being fit. CONCLUSIONS: Previous research has focused only on young people's commuter cycling habits, at the expense of the more common activity of recreational cycling. Recreational cycling may provide an alternative target for interventions to increase physical activity and improve CRF youth. Recreational cycling could potentially serve as a way to gain cycling confidence and establish habits that act as precursors to commuter cycling. © 2012 by the American College of Sports Medicine

SOFT COMPUTING APROACHES TO STOCK FORECASTING: A SURVEY

Soft computing techniques has been effectively applied in business, engineering, medical domain to solve problems in the past decade. However, this paper focuses on censoring the application of soft computing techniques for stock market prediction in the last decade (2010 - todate). Over a hundred published articles on stock price prediction were reviewed. The survey is done by grouping these published articles into: the stock market surveyed, input variable choices, summary of modelling technique applied, comparative studies, and summary of performance measures. This survey aptly shows that soft computing techniques are widely used and it has demonstrated widely acceptability to accurately use for predicting stock price and stock index behavior worldwide