Cantaloupe seed oil     

Walter F. Baughman  Dirk Brauns  George S. Jamieson 《Journal of The Franklin Institute》1921,191(2):283

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The role of preparatory heart rate deceleration on balance beam performance     

Cottyn J  de Clercq D  Crombez G  Lenoir M 《运动与训练心理学杂志》2008,30(2):159-170

Preparatory heart rate deceleration occurs in tasks with an external focus of attention and is often assumed to facilitate balance performance. However, its effects upon sport-related complex balance movements have not been studied. Heart rate patterns during the preparation period of an acrobatic element (flic-flac) on the balance beam were studied in 14 female gymnasts (M age 13.2 years). A significant heart rate deceleration was found in attempts with a fall in the consecutive acrobatic element, but not in attempts without a fall. These data suggest that preparatory heart rate deceleration may be detrimental to the performance of complex movements on the balance beam.  相似文献   

The relationship between peak height velocity and physical performance in youth soccer players   总被引：1，自引：1，他引：0  

Philippaerts RM  Vaeyens R  Janssens M  Van Renterghem B  Matthys D  Craen R  Bourgois J  Vrijens J  Beunen G  Malina RM 《Journal of sports sciences》2006,24(3):221-230

Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.  相似文献   

The energetics and benefit of an arm swing in submaximal and maximal vertical jump performance     

Lees A  Vanrenterghem J  De Clercq D 《Journal of sports sciences》2006,24(1):51-57

The aims of this study were to investigate the energy build-up and dissipation mechanisms associated with using an arm swing in submaximal and maximal vertical jumping and to establish the energy benefit of this arm swing. Twenty adult males were asked to perform a series of submaximal and maximal vertical jumps while using an arm swing. Force, motion and electromyographic data were recorded during each performance and used to compute a range of kinematic and kinetic variables, including ankle, knee, hip, shoulder and elbow joint powers and work done. It was found that the energy benefit of using an arm swing appears to be closely related to the maximum kinetic energy of the arms during their downswing, and increases as jump height increases. As jump height increases, energy in the arms is built up by a greater range of motion at the shoulder and greater effort of the shoulder and elbow muscles but, as jump height approaches maximum, these sources are supplemented by energy supplied by the trunk due to its earlier extension in the movement. The kinetic energy developed by the arms is used to increase their potential energy at take-off but also to store and return energy from the lower limbs and to "pull" on the rest of the body. These latter two mechanisms become more important as jump height increases with the pull being the more important of the two. We conclude that an arm swing contributes to jump performance in submaximal as well as maximal jumping but the energy generation and dissipation sources change as performance approaches maximum.  相似文献   

Zeitökonomische Aspekte der Nachfrage nach Vereinsleichtathletik im europäischen Vergleich     

Dr. phil. Jens Flatau  Werner Pitsch  Dirk Bogendörfer  Eike Emrich 《Sportwissenschaft》2009,39(2):110-119

In a joint project involving European association staff and sports scientists, basic structural data were collected on British, Swedish, Spanish and German athletics clubs to be used for analysis of hypotheses concerning conditions of participation in sports clubs, particularly by children and adolescents. The results showed clear differences in organizational level as well as membership and activity structures in comparisons between European countries and within Germany. The findings revealed the differential functions and significance of sports clubs in the context of the respective institutions and cultures.  相似文献   

The Future of Defunct Religious Buildings: Dutch Approaches to Their Adaptive Re-use     

Kirsten Velthuis & Dirk H. R. Spennemann 《Cultural Trends》2007,16(1):43-66

Across the Western world, membership in the established organized churches is on the decline with a concomitant reduction in the need for churches and church halls. As redundant and unused churches are the focus of vandalism and decay, owners and heritage managers are looking for options to adaptively re-use such buildings. This article reviews the literature on the re-use of churches in the Netherlands, which has long history of innovatively addressing the problems. The options available range from re-use for religious purposes by other denominations or faiths, to community use (multi-purpose, sport, music etc.), and private use, which can be either commercial or residential. The attitudes of the community and the original property owners play a major part in successful adaptive re-use. Because of its long history, the Dutch experience in adaptive re-use of religious buildings has much to offer heritage managers in other countries faced with this emergent management issue.  相似文献   

Known-item Searches Resulting in Zero Hits: Considerations for Discovery Systems     

Christiane Behnert  Dirk Lewandowski 《The Journal of Academic Librarianship》2017,43(2):128-134

The goal of this article is to understand the reasons why known-item search queries entered in a discovery system return zero hits. We analyze a sample of 708 known-item queries and classify them into four categories of zero hits with regard to whether the item is held by the library and whether the query is formulated correctly: (1) item in stock, but query incorrect, (2) item not in stock, (3) item in stock, but incomplete or erroneous metadata, (4) query is ambiguous or not understandable. The main reasons for zero hits are caused by acquisition and erroneous search queries. We discuss possible solutions for known-item queries resulting in zero hits from the side of the system and show that 30% of zero hits could easily be avoided by applying automatic spelling correction. We argue that libraries can improve their discovery systems or online catalogs by applying strategies to avoid or cope with zero hits inspired by web search engines and commercial search web sites.  相似文献   

The orchestration of a collaborative information seeking learning task     

Simon?KnightEmail authorView author&#;s OrcID profile  Bart?Rienties  Karen?Littleton  Dirk?Tempelaar  Matthew?Mitsui  Chirag?Shah 《Information Retrieval》2017,20(5):480-505

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Wider die „Sternchenkunde“!     

Dirk Büsch  Bernd Strauß 《Sportwissenschaft》2016,46(2):53-59

In general, empirical results are analyzed using statistical methods to examine and discuss differences and interrelationships. Statistical methodological evaluation and the underlying reporting strategy can be described as a technical language that has to be learnt for successful communication between researchers, authors and reviewers; however, empirical science is a constantly changing environment which is why the statistical methods applied have to be refined to adhere to new empirical approaches. This line of thought will be discussed in this article and five essential recommendations will be presented: (a) directionality of hypotheses, (b) confidence intervals, (c) effect sizes, (d) confidence intervals of effect sizes and (e) practical meaningfulness.  相似文献   

Predictive value of coaches’ early technical and tactical notational analyses on long-term success of female handball players     

Jörg Schorer  Irene Faber  Till Koopmann  Dirk Büsch  Joseph Baker 《Journal of sports sciences》2020,38(19):2208-2214

ABSTRACT

Despite the importance of technique and tactics for athlete performance, there has been surprisingly little research on the value of these skills in talent identification and development. This study investigated the relationship between coaches’ early notational analyses of female youth handball players and the long-term success of these athletes. Participants included sixty-eight female handball players involved in a talent selection camp in Germany when they were between 12 and 14 years of age (mean = 14.42, SD = 0.42). All subsequently ended up as non-, semi- or professional adult players. During the initial selection camp, participants were evaluated on a range of quantitative and qualitative measures of technical and tactical skill. Results indicated significant differences between the groups, but only for the number of actions taken, not for the quality of those actions. While this seems counterintuitive, it may reflect the likelihood that more skilled and/or talented players take more actions. Further work is necessary to explore the validity and implications of these findings.  相似文献