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The hard X ray beamline BAMline at BESSY II Berlin, Germany has now been in service for 20 amp; 8201;years. Several improvements have been implemented in this time, and this review provides an overview of the imaging methods available at the BAMline. Besides classic full field synchrotron X ray computed tomography SXCT , also absorption edge CT, synchrotron X ray refraction radiography SXRR , and synchrotron X ray refraction tomography SXRCT are used for imaging. Moreover, virtually any of those techniques are currently coupled in amp; 8201;situ or operando with ancillary equipment such as load rigs, furnaces, or potentiostats. Each of the available techniques is explained and both the current and the potential usage are described with corresponding examples. The potential use is manifold, the examples cover organic materials, composite materials, energy related materials, biological samples, and materials related to additive manufacturing. The article includes published examples as well as some unpublished applications

The use of post-processing heat treatments is often considered a necessary approach to relax high-magnitude residual stresses (RS) formed during the layerwise additive manufacturing laser powder bed fusion (LPBF). In this work, three heat treatment strategies using temperatures of 450 °C, 800 °C, and 900 °C are applied to austenitic stainless steel 316L samples manufactured by LPBF. These temperatures encompass the suggested lower and upper bounds of heat treatment temperatures of conventionally processed 316L. The relaxation of the RS is characterized by neutron diffraction (ND), and the associated changes of the microstructure are analyzed using electron backscattered diffraction (EBSD) and scanning electron microscopy (SEM). The lower bound heat treatment variant of 450 °C for 4 hours exhibited high tensile and compressive RS. When applying subsequent heat treatments, we show that stress gradients are still observed after applying 800 °C for 1 hour but almost completely vanish when applying 900 °C for 1 hour. The observed near complete relaxation of the RS appears to be closely related to the evolution of the characteristic subgrain solidification cellular microstructure.

Additive manufacturing (AM) technologies, generally called 3D printing, are widely used because their use provides a high added value in manufacturing complex-shaped components and objects. Defects may occur within the components at different time of manufacturing, and in this regard, non-destructive techniques (NDT) represent a key tool for the quality control of AM components in many industrial fields, such as aerospace, oil and gas, and power industries. In this work, the capability of active thermography and eddy current techniques to detect real imposed defects that are representative of the laser powder bed fusion process has been investigated. A 3D complex shape of defects was revealed by a µCT investigation used as reference results for the other NDT methods. The study was focused on two different types of defects: porosities generated in keyhole mode as well as in lack of fusion mode. Different thermographic and eddy current measurements were carried out on AM samples, providing the capability to detect volumetric irregularly shaped defects using non-destructive methods.

Movement speed is considered essential for success in elite tennis. The aim of the present study was to develop a model of movement speed components and quantify their age- and gender-related relevance for tennis performance. Physical testing data obtained from 1,434 nationally ranked junior squad tennis players were divided according to the age at peak height velocity (YPHV) into two age groups (pre-PHV: n=103 girls, 11.7 ± 0.6 yrs.; n=466 boys, 12.7 ± 1.0 yrs.; post-PHV: n=524 girls, 14.2 ± 1.4 yrs.; n=344 boys, 15.3 ± 1.2 yrs.). After assessing anthropometrics and maturity status, all players passed a series of standardized physical tests on an indoor hard court. All data were z-standardized, filtered and sorted by gender, maturity level, and ranking position. The structuring of the speed-related performance parameters resulted in four factors ('Elementary Speed', 'Jumping Power', 'Linear Speed', and 'COD Speed'), which were then confirmed by factor analysis. The correlation of these factors to the national ranking position was mostly significant but rather low, with 'Linear Speed' reaching the lowest (r=0.10-0.18) and 'COD Speed' the highest correlation (r=0.22-0.34). Path analytic models revealed 'COD Speed' as the most important factor, which is strongly influenced by 'Jumping Power' and 'Linear Speed,' with medium effect sizes, while 'Elementary Speed' affects this factor only slightly. It can be concluded that the relationship between movement speed and junior players' tennis ranking is lower than expected. The development of 'COD Speed' should be prioritized during testing, training, and talent identification, independent of age group and gender.Performance parameters for 1,434 junior players with national rankings were analyzed and assigned to four superior factors.The impact of the factors on the ranking position, as well as the internal causal relationships, were investigated via path analysis.'COD Speed' was the most impactful factor for tennis performance and was strongly influenced by 'Linear Speed' and 'Jumping Power.'

Laser-based additive manufacturing methods allow the production of complex metal structures within a single manufacturing step. However, the localized heat input and the layer-wise manufacturing manner give rise to large thermal gradients. Therefore, large internal stress (IS) during the process (and consequently residual stress (RS) at the end of production) is generated within the parts. This IS or RS can either lead to distortion or cracking during fabrication or in-service part failure, respectively. With this in view, the knowledge on the magnitude and spatial distribution of RS is important to develop strategies for its mitigation. Specifically, diffraction-based methods allow the spatial resolved determination of RS in a non-destructive fashion. In this review, common diffraction-based methods to determine RS in laser-based additive manufactured parts are presented. In fact, the unique microstructures and textures associated to laser-based additive manufacturing processes pose metrological challenges. Based on the literature review, it is recommended to (a) use mechanically relaxed samples measured in several orientations as appropriate strain-free lattice spacing, instead of powder, (b) consider that an appropriate grain-interaction model to calculate diffraction-elastic constants is both material- and texture-dependent and may differ from the conventionally manufactured variant. Further metrological challenges are critically reviewed and future demands in this research field are discussed.

Zusammenfassung Durch den großflächigen Einsatz der Computertomographie (CT) in unterschiedlichen Industriebereichen steigen auch die Anforderungen an die quantitative Bildanalyse. Subjektive Bildwahrnehmung muss durch objektive Algorithmen ersetzt werden. In diesem Artikel stellt die Bundesanstalt für Materialforschung und -prüfung (BAM), die seit den 1980er Jahren an der Entwicklung der industriellen CT beteiligt ist, anhand ausgewählter Beispiele den aktuellen Stand ihrer Analysemethoden an verschiedenen Anwendungsbeispielen der CT vor.

Mechanochemically synthesized metal–organic framework material HKUST-1 in combination with acrylonitrile butadiene styrene polymer was used to form a polymer metal–organic framework composite material by a simple extruder. This composite filament was used for 3D printing. X-ray diffraction measurements were used to prove the homogeneous distribution of the metal–organic framework in the polymer on a centimeter scale, whereas X-ray Absorption Edge Tomography using a synchrotron radiation source was able to evaluate the 3D distribution of the metal–organic framework material both in the filament and the resultant printed sample with a resolution of a few μm. Our very first data indicate that, apart from a few clusters having significantly higher Cu concentration, HKUST-1 is distributed homogeneously down to the 100 μm length scale in both polymer bulk materials in the form of clusters with a size of a few μm. Absorption Edge Tomography in combination with data fusion also allows for the calculation of the metal–organic framework amount located on the external polymer surface.

Laser powder bed fusion is used to create near net shape metal parts with a high degree of freedom in geometry design. When it comes to the production of safety critical components, a strict quality assurance is mandatory. An alternative to cost-intensive non-destructive testing of the produced parts is the utilization of in-situ process monitoring techniques. The formation of defects is linked to deviations of the local thermal history of the part from standard conditions. Therefore, one of the most promising monitoring techniques in additive manufacturing is thermography. In this study, features extracted from thermographic data are utilized to investigate the thermal history of cylindrical metal parts. The influence of process parameters, part geometry and scan strategy on the local heat distribution and on the resulting part porosity are presented. The suitability of the extracted features for in-situ process monitoring is discussed.

The relationship between residual stresses and microstructure associated with a laser powder bed fusion (LPBF) IN718 alloy has been investigated on specimens produced with three different scanning strategies (unidirectional Y-scan, 90° XY-scan, and 67° Rot-scan). Synchrotron X-ray energy-dispersive diffraction (EDXRD) combined with optical profilometry was used to study residual stress (RS) distribution and distortion upon removal of the specimens from the baseplate. The microstructural characterization of both the bulk and the near-surface regions was conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). On the top surfaces of the specimens, the highest RS values are observed in the Y-scan specimen and the lowest in the Rot-scan specimen, while the tendency is inversed on the side lateral surfaces. A considerable amount of RS remains in the specimens after their removal from the baseplate, especially in the Y- and Z-direction (short specimen dimension and building direction (BD), respectively). The distortion measured on the top surface following baseplate thinning and subsequent removal is mainly attributed to the amount of RS released in the build direction. Importantly, it is observed that the additive manufacturing microstructures challenge the use of classic theoretical models for the calculation of diffraction elastic constants (DEC) required for diffraction-based RS analysis. It is found that when the Reuß model is used for the calculation of RS for different crystal planes, as opposed to the conventionally used Kröner model, the results exhibit lower scatter. This is discussed in context of experimental measurements of DEC available in the literature for conventional and additively manufactured Ni-base alloys.

Our study aimed to examine athletics, training characteristics, and prevalence of musculoskeletal symptoms of male junior tennis Davis Cup players (DC) in comparison with their regional counterparts, as well as to evaluate the impact of age and performance level on training characteristics. Twelve junior DC (male) and two samples of regional squad players (RS1 n = 60 males, n = 47 females; RS2 n = 59 males) participated in a physical testing, an interview for data evaluation on training characteristics, and a questionnaire survey of orthopedic injury frequency. Results indicate higher physical performance levels (effect size (ES) 0.75–1.26) and training volumes in DC (ES 1.23–1.66). In DC, significant relationships were found between total training volume and tennis ranking ( r = −0.78), age and physical training volume ( r = 0.82), and age and total training volume ( r = 0.62). Injury frequencies showed moderate to high prevalence with no differences ( p > 0.05) between DC and RS. Given the demands of elite tennis and the important role of service in the modern game, more efforts are necessary to develop training prescription for both performance enhancement and prevention strategies.

This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism.

Das Kinder- und Jugendtraining ist aus Sicht der Trainingswissenschaft fur verschiedene Anwendungsfelder von hoher Relevanz. Diese beinhalten den Freizeit- und Gesundheitssport, den Schulsport, den Vereinssport sowie den Nachwuchsleistungssport und in diesem Zusammenhang die Bereiche der Talentidentifikation und Talentforderung. Empfehlungen fur die Sportpraxis mussen sich an den entwicklungsspezifischen Besonderheiten im Kindes- und Jugendalter orientieren. Im vorliegenden Kapitel wird ein Schwerpunkt auf die biologischen und entwicklungsphysiologischen Besonderheiten gelegt. Vertieft betrachtet werden chronologische und biologische Entwicklung, anaerobe und aerobe Kapazitat, Belastungstoleranz und regenerative Kapazitat bei intensiver Intervallarbeit sowie Hitzetoleranz und Thermoregulation. Hieraus werden grundsatzliche trainingsmethodische Empfehlungen sowie spezielle Hinweise fur das Ausdauer- und Krafttraining im Kindes- und Jugendalter abgeleitet. Gesonderte Kapitel widmen sich dem Nachwuchsleistungssport und den Fragen der Talentidentifikation und Talentforderung, wobei auch Problembereiche wie beispielsweise der Relative Age Effect (RAE) thematisiert werden. Fur den Schulsport werden aus trainingswissenschaftlicher Sicht aktuelle Defizite und zukunftige Moglichkeiten aufgezeigt.

The influence of scan strategy on the residual stress RS state of an as built IN718 alloy produced by means of laser powder bed fusion LPBF is investigated. Two scan vector rotations 90 alternation and 67 rotation , each produced following two different scan vector lengths long and short , are used to manufacture four rectangular prisms. Neutron diffraction ND and laboratory X ray diffraction XRD techniques are used to map the bulk and surface RS state, respectively. The distortion induced upon removal from the baseplate is measured via profilometry. XRD measurements show that the two long scan vector strategies lead to higher RS when compared with the equivalent short scan vector strategies. Also, the 67 rotation strategies generate lower RS than their 90 alternation counterparts. Due to the lack of reliable stress free d0 references, the ND results are analyzed using von Mises stress. In general, ND results show significant RS spatial non uniformity. A comparison between ND and distortion results indicates that the RS component parallel to the building direction Z axis has a predominant role in the Z displacement. The use of a stress balance scheme allows to discuss the d0 variability along the length of the specimens, as well as examine the absolute RS state

A powerful tool to understand, demonstrate and explain the limits of the pulsed technique in terms of detectability and localizability of AM keyhole pores has been assessed by comparing the active thermographic approach (both experimental and FEM simulations) to Computed Tomography results; ✓ µCT results demonstrate that the intended defect geometry is not achieved; indeed a network of voids (microdefects consisting of small sharp-edged hollows with a complicated, almost fractal, inner surface) was found; ✓ both Exp-PT and FEM results explains clearly why no indication of defect related to the thermal contrasts could be found during the investigation of an uncoated surface. However, the application of further data evaluations focusing on the thermal behavior and emissivity evaluation (PPT post data processing) enable the detection of some defects; ✓ coating facilitates a closer inspection of inner defects, but inhomogeneities of the coating could impair the spatial resolution and lead to the emergence of hotspots (the FEM simulation reached its limit with this extreme geometry where a 25 µm thin disc is considered at a 1 cm thick specimen in millisecond time resolution); ✓ both Exp-PT and FEM results allow the conclusion that very short pulses of 200 ms or shorter should be sufficient to detect these defects below, but near the surface; besides a short duration of the thermal phenomenon it should be emphasized, about 0.04 s (high frame rate camera)

The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations: 0 ° , 45 ° , and 90 ° relative to the build plate. Dynamic Young’s modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography ( μ CT), and texture analysis with electron backscatter diffraction (EBSD). These investigations revealed that the specimens exhibited near full density and the detected defects were spherical. Furthermore, the residual stresses in the loading direction were between − 74 ± 24 MPa and 137 ± 20 MPa , and the EBSD measurements showed a preferential 〈 110 〉 orientation parallel to the build direction. A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture.

Fett, J, Ulbricht, A, and Ferrauti, A. Impact of physical performance and anthropometric characteristics on serve velocity in elite junior tennis players. J Strength Cond Res 34(1): 192-202, 2020-This study aimed to investigate the impact of physical performance components and anthropometric characteristics on serve velocity (SV) in elite junior tennis players depending on the sex and age group. A sample of the best 1,019 (male = 625, female = 394) junior squad tennis players of the German Tennis Federation participated in the study involving complex anthropometric measurements (body height, body mass, sitting height, and arm span) and physical tests (e.g., SV, medicine ball throws [MBTs], hand grip strength, push-ups, back extension, countermovement jumps [CMJs], horizontal jumps, 20-m sprint, and tennis-specific endurance). Of all the anthropometric and physical characteristics analyzed, the MBTs (r = 0.49-0.60♂; r = 0.20-0.60♀), hand grip strength (r = 0.43-0.59♂; r = 0.27-0.37♀), arm span (r = 0.37-0.56♂; r = 0.24-0.36♀), body height (r = 0.31-0.52♂; r = 0.26-0.38♀), and body mass (r = 0.44-0.57♂; r = 0.35-0.39♀) were particularly closely correlated with SV. The results of the multiple regression analysis indicated that the combination of selected predictors (e.g., MBTs, grip strength, arm span, and body mass) explained 41-66% of the variance in SV of boys and 19-45%, respectively, for girls. The results reinforce that service speed is dependent on physical abilities and anthropometric characteristics but also strongly on additional factors (i.e., technical components). In particular, the upper-body power/strength is important to the junior players' service, especially in athletes with a greater body height and arm span (i.e., biomechanical advantages), whereas purely lower-body power (e.g., CMJ) is less important. To this effect, talent identification and intervention programs focusing on the specific requirements are recommended.

The aims of the study were to test: 1) whether the relative age effect (RAE) was prevalent in young (U12-U18) German male tennis players; 2) the potential influence of age and/or skill level on RAE and 3) whether maturity, anthropometric and fitness measures vary according to birth date distribution in elite youth tennis players. For the present study the following male populations were analysed: Overall German population (n = 3.216.811), all players affiliated to the German Tennis Federation (DTB) (n = 120.851), players with DTB official ranking (n = 7165), regional (n = 381) and national (n = 57) squads (11-17 years old), as well as the top 50 German senior players were analyzed. RAEs were more prevalent at higher competitive levels with more players born in the first quarter of the year compared with the reference population for ranked (29.6%), regional (38.1%) and national (42.1%) players. No systematic differences were found in any of the maturity, anthropometric and fitness characteristics of the regional squad players born across different quarters. RAEs are present in the DTB competitive system and it was more pronounced at higher competitive levels. Compared with early born, late born players who were selected into elite squads did not differ in maturation, anthropometric and fitness characteristics.

Tennis requires a complex interaction of technical, tactical, psychological, and several physical components (i.e., strength, agility) and metabolic pathways (i.e., aerobic and anaerobic) [1] (Fig. 12.1). In order to achieve an optimum cost-benefit ratio of training input, goals and contents during physical conditioning must be defined according to the specific workload and the most important limiting performance factors in tennis but also closely corresponding to the individual needs (strengths and weaknesses) of each athlete. The dominance of the technical and tactical requirements for tennis performance can be figured out by an upper position in a hierarchical model of performance-limiting aspects (Fig. 12.1). The weekly training volume has to be adjusted correspondingly, and the respective volume for physical conditioning remains comparably low. Therefore, on an elite performance level, it becomes of predominant importance that physical training has to be combined with technical and tactical training on-court and during off-court sessions that should meet precisely the individual requirements which have to be regularly assessed by physical performance tests [2–5].

Zusammenfassung Hintergrund Im modernen Leistungstennis gewinnt die Athletik zunehmend an Bedeutung, obwohl Technik und Taktik nach wie vor primar leistungslimitierend sind. Folglich sollte das Konditionstraining moglichst individualisiert und dadurch ressourcensparend sein. Der Deutsche Tennis Bund betreibt seit vier Jahren eine konditionelle Leistungsdiagnostik mit allen Kaderspielern auf dessen Grundlage individuell angepasste Trainingsempfehlungen gegeben werden. Der vorliegende Beitrag beschreibt die Durchfuhrung der Testbatterie und verdeutlicht anhand von zwei Fallbeispielen den Wert von differenzierten leistungsdiagnostischen Befunden fur eine individuelle zielgerichtete Ausrichtung des Konditionstrainings. Methoden Im Zeitraum von 2009-2013 nahmen 1052 mannliche und weibliche C-/D-Kaderspieler im Alter von 10 bis 18 Jahren am ⿿DTB-Konditionstest⿿ teil. Dieser beinhaltet standardisierte anthropometrische und konditionelle Untersuchungen. Resultate Grundlage der individuellen Leistungssteuerung ist der Vergleich der Individualbefunde mit alters-, geschlechts- und entwicklungsrelativierten Normprofilen, deren Anwendung anhand von zwei Beispielen verdeutlicht wird. Die entwickelten Normprofile basieren auf Halbjahresgruppierungen und berucksichtigen sowohl das chronologische als auch das biologische Alter. Schlussfolgerungen Die Fallbeispiele verdeutlichen die Notwendigkeit entwicklungsrelativierter Normprofile fur eine individuelle, zielgerichtete Ausrichtung des Konditionstrainings. Auf der Grundlage der Ergebnisse werden eindeutige Starken und Schwachen in den unterschiedlichen motorischen Hauptfaktoren deutlich gemacht, so kann eine klare Schwerpunktsetzung fur das Training empfohlen werden.

Background Analysis of court surface effects on foot work and running speed and analysis of correlation between general speed and jump performance and the complex running performance in tennis. Materials and Methods 12 male tennis players performed a tennis specific baseline shuttle run test including one change of direction (SR), either on clay or on an indoor carpet court. Additionally, subjects completed a linear sprint test, a counter movement jump (CMJ), and a drop jump (DJ). Results SR running time (clay: 3.63 ± 0.08 s; carpet: 3.31 ± 0.15 s), change direction time (clay: 1.24 ± 0.09; carpet: 1.09 ± 0.04 s) and ground contact time during the last step while changing direction (clay: 0.92 ± 0.13; carpet: 0.47 ± 0.13 s) were significantly longer on clay (P Conclusion Foot work and running speed demands in tennis are different depending on the court surface and require specific training interventions and testing procedures.

The 3D shape of X-ray reflections from the γ/γ′-microstructure of a nickel-base superalloy was investigated using synchrotron X-ray radiation and a position sensitive area detector. The measurements were performed on the 4th generation single-crystal nickel-base superalloy TMS138. The results show that X-ray reflections from non-cubic crystallographic planes have a complex 3D shape which changes during rafting. The 3D intensity distributions contain information about the spacing of the planes and their orientation as well. Whereas h00 reflections show the usual splitting into a γ′ and one γ-subreflection, the hh0 and hhh reflections show two and three γ-peaks respectively, resulting from the different types of {100} matrix channels. Therefore, these 3D diffraction measurements supply additional information about the spatial distribution of microstrains.

The impact of fitness characteristics on tennis performance in adolescent players is not clearly understood. Therefore, the aim of the present study was to test whether physical characteristics are related to players' competitive level (i.e., national youth ranking). A secondary aim was to compare adolescent tennis players by performance level (i.e., regional selected players and the national team). A total of 902 male and female junior players (aged, 11-16 years) in Germany were evaluated using a physical testing battery: grip strength; countermovement jump; 10 and 20-m sprint; tennis-specific sprint; overhead, forehand, and backhand medicine ball throws (MBT); serve velocity and tennis-specific endurance test (hit and turn tennis test). Results showed that serve velocity (r = -0.43 to 0.64 for female subjects [♀]; r = -0.33 to 0.49 for male subjects [♂]) and upper-body power (e.g., MBT r = -0.26 to -0.49 ♀; r = -0.20 to -0.49 ♂) were the most correlated predictors of tennis performance (i.e., national youth ranking) in both female and male tennis players. Moreover, national selected players showed better performance levels than their regional counterparts, mainly in the most predictive physical characteristics (i.e., serve velocity: effect size [ES], 0.78-1.04 ♀; ES 0.92-1.02 ♂, MBT: ES, 0.66-0.88 ♀; ES, 0.67-1.04 ♂) and specific endurance (ES, 0.05-0.95 ♀; ES, 0.31-0.73 ♂). The present findings underline the importance of certain physical attributes, especially serve velocity and strength- and power-related variables (upper body), and suggest the need to include these parameters in the area of training, physical testing, and talent identification of young tennis players.

In tennis, sport-specific technical skills are predominant factors, although a complex profile of physical performance factors is also required. The fitness test batteries assist in examining tennis players’ capabilities for performance at different levels in the laboratory as well as in the field, in the junior or elite level. While laboratory tests can be, and are, used to evaluate basic performance characteristics of athletes in most individual sports, in a more specific approach, field-based methods are better suited to the demands of complex intermittent sports like tennis. A regular test battery performed at different periods of the year allows to obtain an individual's performance profile, as well as the ability to prescribe individual training interventions. Thus, the aim of the present review was to describe and evaluate the different physical tests recommended and used by practitioners, sports scientists and institutions (national tennis federations).

This book analyzes political decentralization and fiscal federalism in Canada and Germany, both traditional federal countries, and in Spain, a unitarian country engaged in the last two decades in a process of decentralization. Three key issues required for a well designed financing system are analyzed in depth, namely: tax assignment, equalization grants – i.e. redistribution of money from the wealthy regions or the national government to poorer regions, and the role of local governments in the administration of taxes.