Nutrition for the young athlete     

Meyer F  O'Connor H  Shirreffs SM;International Association of Athletics Federations 《Journal of sports sciences》2007,25(Z1):S73-S82

Athletics is a popular sport among young people. To maintain health and optimize growth and athletic performance, young athletes need to consume an appropriate diet. Unfortunately, the dietary intake of many young athletes follows population trends rather than public health or sports nutrition recommendations. To optimize performance in some disciplines, young athletes may strive to achieve a lower body weight or body fat content and this may increase their risk for delayed growth and maturation, amenorrhoea, reduced bone density, and eating disorders. Although many of the sports nutrition principles identified for adults are similar to those for young athletes, there are some important differences. These include a higher metabolic cost of locomotion and preferential fat oxidation in young athletes during exercise. Young athletes, particularity children, are at a thermoregulatory disadvantage due to a higher surface area to weight ratio, a slower acclimatization, and lower sweating rate. An appropriate dietary intake rather than use of supplements (except when clinically indicated) is recommended to ensure young athletes participate fully and safely in athletics.  相似文献   

The female athlete triad: components, nutrition issues, and health consequences     

Manore MM  Kam LC  Loucks AB;International Association of Athletics Federations 《Journal of sports sciences》2007,25(Z1):S61-S71

This paper, which was part of the International Association of Athletics Federations (IAAF) 2007 Nutritional Consensus Conference, briefly reviews the components of the female athlete triad (Triad): energy availability, menstrual status, and bone health. Each component of the Triad spans a continuum from health to disease, and female athletes can have symptoms related to each component of the Triad to different degrees. Low energy availability is the primary factor that impairs menstrual dysfunction and bone health in the Triad. We discuss nutritional issues associated with the Triad, focusing on intakes of macronutrients needed for good health, and stress fractures, the most common injury associated with the Triad. Finally, we briefly discuss screening and treatment for the Triad and the occurrence of the Triad in men.  相似文献   

The influence of achievement motivation and chess-specific motivation on deliberate practice     

de Bruin AB  Rikers RM  Schmidt HG 《运动与训练心理学杂志》2007,29(5):561-583

Although the importance of high motivation to engage in deliberate practice has been acknowledged, no research has directly tested this hypothesis. Therefore, the present study examined this relation in adolescent elite chess players by means of a questionnaire. In addition, to provide an explanation for dropout among promising chess players, differences in motivation between persistent and dropout chess players were analyzed. Competitiveness and the will to excel proved to be predictors of investments in deliberate practice. Moreover, achievement motivation and chess-specific motivation differed to a certain extent between persisters and dropouts. Our results suggest that motivation to engage in deliberate practice not only contains elements of the will to improve performance, but also of the will to attain exceptional levels of performance.  相似文献   

Whole-body vibration can reduce calciuria induced by high protein intakes and may counteract bone resorption: A preliminary study     

Cardinale M  Leiper J  Farajian P  Heer M 《Journal of sports sciences》2007,25(1):111-119

Excess protein intake can adversely affect the bone via an increase in calcium excretion, while suitable mechanical loading promotes osteogenesis. We therefore investigated whether vibration exposure could alleviate the bone mineral losses associated with a metabolic acidosis. Ten healthy individuals aged 22 - 29 years (median = 25) underwent three 5-day study periods while monitoring their dietary intake. The study consisted of recording the participants' usual dietary intake for 5 consecutive days. Participants were then randomly divided into two groups, one of which received a protein supplement (2 g x kg(-1) body mass x day(-1); n = 5) and the other whole-body low-magnitude (3.5 g), low-frequency (30 Hz) mechanical vibration (WBV) delivered through a specially designed vibrating plate for 10 min each day (n = 5). Finally, for the third treatment period, all participants consumed the protein supplement added to their normal diet and were exposed to WBV exercise for 10 min per day. Daily urine samples were collected throughout the experimental periods to determine the excretion of calcium, phosphate, titratable acid, urea, and C-telopeptide. As expected, when the participants underwent the high protein intake, there was an increase in urinary excretion rates of calcium (P < 0.001), phosphate (P < 0.003), urea (P < 0.001), titratable acid (P < 0.001), and C-telopeptide (P < 0.05) compared with baseline values. However, high protein intake coupled with vibration stimulation resulted in a significant reduction in urinary calcium (P = 0.006), phosphate excretion (P = 0.021), and C-telopeptide (P < 0.05) compared with protein intake alone, but did not affect titratable acid and urea output. The participants showed no effect of WBV exercise alone on urinary excretion of calcium, phosphate, urea, titratable acid, or C-telopeptide. The results indicate that vibration stimulation can moderate the increase in bone resorption and reduction in bone formation caused by a metabolic acidosis.  相似文献   

Why young elite athletes fear failure: consequences of failure   总被引：1，自引：0，他引：1  

Sagar SS  Lavallee D  Spray CM 《Journal of sports sciences》2007,25(11):1171-1184

Fear of failure can have negative effects on children in achievement settings, affecting many aspects of their lives. Perceiving the consequences of failure to be aversive provides the basis for fear of failure, and the anticipation of a threatening outcome elicits fear. Problems attributed to fear of failure in achievement settings are prevalent. Sport is a popular and significant achievement domain for children and adolescents and there is a lack of research on fear of failure in sport among this age group. Therefore, the aim of the present study was to investigate fear of failure in the sport domain among young elite athletes, and to explore their perceptions of the consequences of failure. Interviews were conducted individually with nine athletes aged 14 - 17 years (5 males, 4 females). Analysis identified and organized perceived consequences of failure into themes and categories. Results revealed that the most commonly perceived aversive consequences of failure were diminished perception of self, no sense of achievement, and the emotional cost of failure. These findings are consistent with those reported in adult population, suggesting the potential for generalizing existing results to young elite athletes.  相似文献   

How should cultural diversity be measured? An application using the French publishing industry     

Françoise Benhamou  Stéphanie Peltier 《Journal of Cultural Economics》2007,31(2):85-107

Despite the lack of a clear definition of the concept, “cultural diversity” has remained a core issue for more than a decade (WTO, UNESCO, etc.). The aim of this paper is to begin to fill this gap. We argue that cultural diversity is a multi-dimensional concept and that accurate metrics must rely on three criteria: variety, balance and disparity. We also stress that supplied and consumed diversity have to be distinguished. We apply this set of multiple measures of diversity to publishing data for France over the period 1990–2003. Our main result is that the situation of the publishing industry in terms of cultural diversity is highly dependent on the dimension considered. Hence, diversity increases when variety is the sole consideration, whereas taking balance or disparity into account leads to the opposite conclusion. This issue raises a series of questions about the use of diversity measures in a policy debate concerned with furthering cultural diversity.

Stéphanie PeltierEmail:

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Programmatic choices and the demand for theatre: the case of Flemish theatres   总被引：4，自引：2，他引：2  

Kristien Werck  Bruno Heyndels 《Journal of Cultural Economics》2007,31(1):25-41

Theatre experts generally agree that the Flemish theatre has flourished artistically over the period 1980–2000. Attendance, on the other hand, has declined significantly. Following Lancaster’s characteristics approach, we identify several output characteristics of individual theatre productions. Using a panel of 59 Flemish theatres, we examine the impact on demand of both these output characteristics and of traditional determinants such as own price, income and the price of substitutes. Differences in the relevant geographical market for touring and non-touring theatres are considered. We find that the nature of the artistic output affects demand. Theatregoers prefer large productions (in terms of cast size), plays by Dutch-speaking playwrights and revivals of old productions. Own price and consumer income have the expected negative and positive effects on attendance. Observed trends toward a decreasing proportion of new plays, an increasing presence of plays by Dutch-speaking playwrights, and increasing consumer income had a stimulating effect on attendance. These trends have been offset, however, by trends toward smaller cast sizes and higher ticket prices as well as by unobserved factors captured by time dummies. The net result has been a considerable drop in attendance.

Kristien WerckEmail:

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The law of one price,noise and “irrational exuberance”: the auction market for Picasso prints     

James E. Pesando  Pauline M. Shum 《Journal of Cultural Economics》2007,31(4):263-277

We use prices realized for Picasso prints at auctions worldwide, as well as the 100 prints that comprise his Vollard Suite, to test the law of one price: the proposition that identical art objects sold contemporaneously should command the same price regardless of the auction house or geographic region where the sale takes place. Picasso is the most prolific printmaker of the twentieth century and, from 1977 to 2004, his prints appreciated in price significantly faster than the prints of modern masters as a whole. We find that Picasso prints sold in the United States command higher prices than in Europe. However, prices realized at Sotheby’s in New York are no longer higher than at Christie’s in New York, nor at Kornfeld than at other auction houses. We find evidence of “irrational exuberance” in the transitory nature of the extraordinary prices realized for the Picasso prints included in the 1997 sale of the collection of Victor and Sally Ganz at Christie’s in New York. More generally, we find substantial noise in auction outcomes, a result well known to savvy auction goers.

Pauline M. Shum (Corresponding author)Email:

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Geographic clustering of economic activity: The case of prominent western visual artists   总被引：1，自引：1，他引：0  

Elish Kelly  John O’Hagan 《Journal of Cultural Economics》2007,31(2):109-128

This article compiles original data relating to artists’ place of birth and work migration patterns using various art history dictionaries. The broad historic pattern, from the 13th to the 20th century, of the birth locations of prominent artists is examined, followed by a detailed study of the work migration patterns of prominent artists in two important situations, namely Renaissance Italy and France in part of the 19th century. The evidence indicates a marked clustering of activity of prominent artists, both arising from birth location and migration patterns. Some possible explanations for the observed patterns are briefly outlined.

John O’HaganEmail:

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Two games in town: a comparison of dealer and auction prices in contemporary visual arts markets     

Michael Hutter  Christian Knebel  Gunnar Pietzner  Maren Schäfer 《Journal of Cultural Economics》2007,31(4):247-261

The article tests a couple of hypotheses relating to markets where demand is not taken as a given, but subject to sophisticated and encompassing price-building strategies. The study uses a data set that provides quoted dealer prices for medium-sized works of 100 leading visual artists from 1970 to 2004. These data are compared with auction price results for works by the same artists. The study reports significant discrepancies with respect to the relationship between the age of artists and prices paid for their works in the two markets, and with respect to general price developments in the two markets as measured by indices.

Michael HutterEmail:

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