1,046 research outputs found
The effect of carbohydrate ingestion on the motor skill proficiency of soccer players
This study examined the effects of ingesting a glucose-polymer (GP) solution on the motor skill proficiencies of association football (soccer) players from two teams playing during two matches in a cool environment. Fifteen minutes before each match and at halftime, players from both teams ingested 5 ml/kg of either placebo or a 6.9% GP solution. GP ingestion did not improve tackling, heading, dribbling, or shooting ability. On the contrary, the mean of successful tackles was lower with GP ingestion than with placebo. The success rate for heading, dribbling, and shooting also tended to be lower in the GP than in the placebo condition. In contrast, success in passing and ball control was similar in the two conditions. Improvements in passing and ball control may have been related to a decrease in the intensity of play in the second half of the game. These data indicate that there are no measurable benefits of GP ingestion for the motor skill proficiencies of soccer players during games played in a cool environment.IS
Domestic burglary drop and the security hypothesis
This study examines the role of household security devices in producing the domestic burglary falls in England and
Wales. It extends the study of the security hypothesis as an explanation for the 'crime drop'. Crime Survey for England
and Wales data are analysed from 1992 to 2011/12 via a series of data signatures indicating the nature of, and change in, the relationship between security devices and burglary. The causal role of improved security is strongly indicated by a set of interlocking data signatures: rapid increases in the prevalence of security, particularly in the availability of combinations of the most effective devices (door and window locks plus security lighting); a steep decline in the pro-portion of households without security accompanied by disproportionate rises in their burglary risk; and the decline being solely in forced rather than unforced entries to households. The study concludes that there is strong evidence that security caused the decline in burglary in England and Wales in the 1990s. Testing the security hypothesis across a wider range of crime types, countries and forms of security than examined to date, is required both to understand the crime drop and to derive lessons for future crime prevention practice and policy
Activity profile of top-class association football referees in relation to fitness test performance and match standard
The aim of this study was to examine the kinematic activity profiles, cardiovascular responses and physical fitness of top-class football referees (n=11) during the FIFA Confederations Cup 2005. Computerised match-analyses (n=9) were performed with a two-dimensional photogrammetric video system, and the cardiovascular demand imposed on the referees (n=12) was measured using heart rate recordings. Total distance covered was 10,218, s=643 m of which 3531, s=510 m was covered at high intensities (>3.6 m.s(-1)). Both total distance covered (r2=0.59; P=0.02) and high-intensity activities (r2=0.44; P=0.05) were related to the distance covered by the ball in the same match. The referees ran at high speed 37% further (P=0.01) in the actual tournament than during under-17 top-level officiating. After the 5-min interval during which high-speed running peaked, in the following 5 min the performance was reduced by 19% (P=0.01) in relation to the mean of the game. Mean heart rate was 161, s=9 b.min(-1) (86, s=3% of maximal heart rate (HRmax)). Mean heart rate (expressed as percentage of HRmax) was related in part (r2=0.36; P5 m.s(-1)) best describes the physical performance of referees; (3) heart rate recording can be a useful tool to determine the most intense periods of a match and (4) the new fitness tests adopted by FIFA were poor predictors of match activities
Tracking of fatness during childhood, adolescence and young adulthood: a 7-year follow-up study in Madeira Island, Portugal
Aims: Investigating tracking of fatness from childhood to adolescence, early adolescence to young adulthood and late adolescence to young adulthood. Subjects and methods: Participants from the Madeira Growth Study were followed during an average period of 7.2 years. Height, body mass, skin-folds and circumferences were measured, nine health- and performance-related tests were administered and the Baecke questionnaire was used to assess physical activity. Skeletal maturity was estimated using the TW3 method. Results: The prevalence of overweight plus obesity ranged from 8.2–20.0% at baseline and from 20.4–40.0% at followup, in boys. Corresponding percentages for girls were 10.6– 12.0% and 13.2–18.0%. Inter-age correlations for fatness indicators ranged from 0.43–0.77. BMI, waist circumference and sum of skin-folds at 8, 12 and 16-years old were the main predictors of these variables at 15, 19 and 23-years old, respectively. Strength, muscular endurance and aerobic fitness were negatively related to body fatness. Physical activity and maturation were independently associated with adolescent (15 years) and young adult (19 years) fatness. Conclusions: Over 7.2 years, tracking was moderate-to-high for fatness. Variance was explained by fatness indicators and to a small extent by physical fitness, physical activity and maturation
Population genomics of marine zooplankton
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Bucklin, Ann et al. "Population Genomics of Marine Zooplankton." Population Genomics: Marine Organisms. Ed. Om P. Rajora and Marjorie Oleksiak. Springer, 2018. doi:10.1007/13836_2017_9.The exceptionally large population size and cosmopolitan biogeographic distribution that
distinguish many – but not all – marine zooplankton species generate similarly exceptional patterns of
population genetic and genomic diversity and structure. The phylogenetic diversity of zooplankton has
slowed the application of population genomic approaches, due to lack of genomic resources for closelyrelated
species and diversity of genomic architecture, including highly-replicated genomes of many
crustaceans. Use of numerous genomic markers, especially single nucleotide polymorphisms (SNPs), is
transforming our ability to analyze population genetics and connectivity of marine zooplankton, and
providing new understanding and different answers than earlier analyses, which typically used
mitochondrial DNA and microsatellite markers. Population genomic approaches have confirmed that,
despite high dispersal potential, many zooplankton species exhibit genetic structuring among geographic
populations, especially at large ocean-basin scales, and have revealed patterns and pathways of population
connectivity that do not always track ocean circulation. Genomic and transcriptomic resources are
critically needed to allow further examination of micro-evolution and local adaptation, including
identification of genes that show evidence of selection. These new tools will also enable further
examination of the significance of small-scale genetic heterogeneity of marine zooplankton, to
discriminate genetic “noise” in large and patchy populations from local adaptation to environmental
conditions and change.Support was provided by the
US National Science Foundation to AB and RJO (PLR-1044982) and to RJO (MCB-1613856); support to
IS and MC was provided by Nord University (Norway)
Half-Time Strategies to Enhance Second-Half Performance in Team-Sports Players: A Review and Recommendations
The competitive demands of numerous intermittent team sports require that two consecutive periods of play are separated by a half-time break. Typically, half-time allows players to: return to the changing rooms, temporarily relax from the cognitive demands of the first half of match-play, rehydrate, re-fuel, attend to injury or equipment concerns, and to receive tactical instruction and coach feedback in preparation for the second half. These passive practices have been associated with physiological changes which impair physical and cognitive performance in the initial stages of the second half. An increased risk of injury has also been observed following half-time. On the day of competition, modification of half-time practices may therefore provide Sports Scientists and Strength and Conditioning Coaches with an opportunity to optimise second half performance. An overview of strategies that may benefit team sports athletes is presented; specifically, the efficacy of: heat maintenance strategies (including passive and active methods), hormonal priming (through video feedback), post-activation potentiation, and modified hydro-nutritional practices are discussed. A theoretical model of applying these strategies in a manner that compliments current practice is also presented
Manipulating Permeability as a Process for Controlling Crime: Balancing Security and Sustainability in Local Contexts
In response to the sustainability agenda, planning policy in the UK, USA and Australia has shifted to promote compact, high-density, mixed-used residential developments in walkable and permeable street networks close to public transport (Commonwealth of Australia, 1995; DETR, 1998; American Planning Association, 2007). This is to encourage walking and the use of public transport and to reduce car-use, energy use, pollution, congestion and urban sprawl. However, although permeability is assumed to represent a positive built environment feature which reduces crime by promoting more "eyes on the street" (Jacobs, 1961), a significant body of research in the field of environmental criminology challenges this assumptions. This paper reviews the theories and evidence associated with permeability and crime.Pedestrian access ways (PAWs) are often associated with crime and this paper discusses research which was directed at providing practical guidance to local governments on how they could better manage existing PAWs in Western Australia (WA). A morphological analysis of existing PAWs was undertaken which analysed the purposes, roles, functionality, users and dynamics of PAWs in a variety of different settings. In addition to crime (which had commonly be used as an excuse to close PAWs), the research considered issues such as amenity, walkability, equity and sustainability. A suite of five tools for assessing and reducing crime risk were developed, which attempt to balance security and sustainability issues. Contrary to assumptions, most PAWs were not subject to high levels of crime and many were vital to the community. Intriguingly, findings indicated that neighbourhood permeability can potentially be manipulated (via the management, closure or construction of new PAWs) to achieve the desired outcomes of reducing crime and of enhancing walkability, liveability and ultimately, the sustainability and well-being of communities
Changes in BMI-distribution from 1966–69 to 1995–97 in adolescents. The Young-HUNT study, Norway
Background
The aim of this study was to explore changes in the BMI-distribution over time among Norwegian adolescents.
Methods
Height and weight were measured in standardised ways and BMI computed in 6774 adolescents 14–18 years who participated in the Young-HUNT study, the youth part of the Health-study of Nord-Trondelag County, Norway in 1995–97. The results were compared to data from 8378 adolescents, in the same age group and living in the same geographical region, collected by the National Health Screening Service in 1966–69.
Results
From 1966–69 to 1995–97 there was an increased dispersion and a two-sided change in the BMI-distribution. Mean BMI did not increase in girls aged 14–17, but increased significantly in 18 year old girls and in boys of all ages. In both sexes and all ages there was a significant increase in the upper percentiles, but also a trend towards a decrease in the lowest percentiles. Height and weight increased significantly in both sexes and all ages.
Conclusion
The increased dispersion of the BMI-distribution with a substantial increase in upper BMI-percentiles followed the same pattern seen in other European countries and the United States. The lack of increase in mean BMI among girls, and the decrease in the lowest percentiles has not been acknowledged in previous studies, and may call for attention
Physiological Responses and Physical Performance during Football in the Heat
PURPOSE: To examine the impact of hot ambient conditions on physical performance and physiological responses during football match-play. METHODS: Two experimental games were completed in temperate (∼ 21°C; CON) and hot ambient conditions (∼ 43°C; HOT). Physical performance was assessed by match analysis in 17 male elite players during the games and a repeated sprint test was conducted after the two game trials. Core and muscle temperature were measured and blood samples were obtained, before and after the games. RESULTS: Muscle and core temperatures were ∼ 1°C higher (P<0.05) in HOT (40.3 ± 0.1 and 39.5 ± 0.1°C, respectively) compared to CON (39.2 ± 0.1 and 38.3 ± 0.1°C). Average heart rate, plasma lactate concentration, body weight loss as well as post-game sprint performance were similar between the two conditions. Total game distance declined (P<0.05) by 7% and high intensity running (>14 km ⋅ h(-1)) by 26% in HOT compared to CON), but peak sprint speed was 4% higher (P<0.05) in HOT than in CON, while there were no differences in the quantity or length of sprints (>24 km ⋅ h(-1)) between CON and HOT. In HOT, success rates for passes and crosses were 8 and 9% higher (P<0.05), respectively, compared to CON. Delta increase in core temperature and absolute core temperature in HOT were correlated to total game distance in the heat (r = 0.85 and r = 0.53, respectively; P<0.05), whereas, total and high intensity distance deficit between CON and HOT were not correlated to absolute or delta changes in muscle or core temperature. CONCLUSION: Total game distance and especially high intensity running were lower during a football game in the heat, but these changes were not directly related to the absolute or relative changes in core or muscle temperature. However, peak sprinting speed and execution of successful passes and crosses were improved in the HOT condition
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