The relationship between peak height velocity and physical performance in youth soccer players

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.     

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

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.     

Picking the winners by consensus: Grant-giving practice in the Netherlands

The Netherlands form a consensus democracy. In such a society the legitimacy of decisions is of great concern to all. An elaborate system of checks and balances tends to exist and the pressure to join an emerging consensus at meetings is both subtle and tremendously powerful. In the Dutch system of higher education and research the manifestations of the consensus ideal are numerous. This paper highlights them where appropriate. It reviews the Dutch research effort in an international perspective and concludes that R&D expenditure in the Netherlands, measured as a proportion of GDP, is declining. Fairly radical changes in science policy orientation since the 1960s are reviewed and the current frameworks for policy formulation, academic foresight and the organisation of support are sketched. After discussing NWO's different funding instruments, the practices of picking the winners are described in some detail. Three different peer review models are then discussed with special attention to their strengths and weaknesses. The paper's final section is focussed on the evaluation practices in force.     

Language proficiency and lateral position in the classroom

This paper not only makes a contribution to the mosaic of scientific knowledge of the brain and nervous system, but suggests implications of practical value. Observant, experienced teachers know empirically that some youngsters learn best, and perhaps only, when seated front-center, right before the teacher’s desk. Such children need to have the eye contact, or to be in quick arm’s reach, or to have distractions screened out. Drs. Bakker and Van Rijnsoever give evidence here that, for many children, taking in and remembering the message is dependent on their physical placement to catch most effectively the stream of sound. This is important to consider in the popular open classroom. Although many children can adapt readily to less-than-perfect physical learning conditions, for some we must “re-invent the wall,” not to climb, but to provide a place to call “home.” The theoretical re-inforcement presented in this paper proves that such boundaries can also provide source and direction for sound as part of some children’s currently needed sensory security and enhance the efficiency of their auditory intake. Editor     

Zeitökonomische Aspekte der Nachfrage nach Vereinsleichtathletik im europäischen Vergleich

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.     

The role of preparatory heart rate deceleration on balance beam performance

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.     

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

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.