The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players

Abstract Background Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance. Methods Twelve male professional soccer players (23 ± 5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg− 1) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively). Results Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11] = 14.99, P  0.05) compared to placebo. Conclusions The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players

A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running

Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs

Archaeological Ethnography, Heritage Management, and Community Archaeology: A Pragmatic Approach from Crete

This article examines the introduction of archaeological ethnography as an approach to establish positioned research and bring context-specific and reflexive considerations into community archaeology projects. It considers recent cri-tiques of heritage management in archaeology and the role of archaeologists as experts in it, contending that smaller and less prominent sites exist in different contexts and pose different problems than large-scale projects usually addressed in the literature. We describe how the ‘Three Peak Sanctuaries of Central Crete’ project, investigating prehistoric Minoan ritual sites, involves communities and stakeholders and what demands the latter pose on experts in the field. Archae-ological work is always already implicated in local development projects which create and reproduce power hierarchies. It is therefore important that archaeol-ogists maintain their critical distance from official heritage discourses, as they are materialized in development programmes, while at the same time engaging with local expectations and power struggles; they also have to critically address and position their own assumptions. We use examples from our community archae-ology project to propose that these goals can be reached through archaeological ethnographic fieldwork that should precede any archaeological project to inform its methodological decisions, engage stakeholders, and collaboratively shape heritage management strategies

The Spatial Aspects of Enterprise Learning in Transition Countries

This paper investigates the sources of enterprise learning under transition, using the results of a recent survey conducted in six Central and East European countries. The analysis identifies three possible and interacting ways of enterprise learning: (1) learning by doing; (2) learning from the environment; and (3) learning from networks. Then it examines the spatial variations of the factors affecting learning by contrasting capital regions with western border regions and all sampled firms. The paper concludes that enterprise learning in transition economies is a spatially selective process, as most structural and behavioural factors tend to favour capital regions. Consequently, transition policies have to incorporate certain types of regional policy into their core, as a supplementary and balancing force to market-driven structural and spatial adjustments. A partir d'une enquete recente menee en six pays de l'Europe centrale et orientale, cet article cherche a examiner les origines de l'apprentissage d'entreprise dans les pays en voie de transition. L'analyse distingue trois facons eventuelles qui agissent l'une sur l'autre: (1) apprendre sur le tas; (2) apprendre en milieu; et (3) apprendre en reseau. Il s'ensuit un examen des variations spatiales des facteurs qui influent sur l'apprentissage en comparant les regions principales aux regions frontalieres occidentales et a toutes les entreprises qui figurent dans l'echantillon. On conclut que l'apprentissage d'entreprise dans les economies en voie de transition s'avere un processus selectif du point de vue spatial, vu que la plupart des facteurs structurels et de comportement ont tendance a favoriser les regions principales. Par consequent, les politiques de transition doivent incorporer des politiques regionales particulieres comme force supplementaire et d'equilibre face aux ajustements structurels et spatiaux qui sont determines par les contraintes du marche. Dieser Aufsatz untersucht die Quellen der Vermittlung von Kenntnissen zur Betriebsfuhrung unter Ubergangsbedingungen, wobei er sich auf die Ergebnisse einer kurzlich in sechs Landern Mittel-und Osteuropas durchgefuhrten Umfrage stutzt. Die Analyse stellt drei mogliche, und aufeinander einwirkende Arten der Vermittlung von Kenntnissen zur Betriebsfuhrung vor: (1) Lernen durch Tun; (2) Lernen von der Umwelt; und (3) Lernen von Netzwerken. Sodann untersucht sie die raumlichen Abweichungen der Faktoren, die sich auf Lernprozesse auswirken, indem sie Hauptstadtregionen den westlichen Grenzgebiete und allen untersuchten Firmen gegenuberstellt. Der Aufsatz folgert, dass Vermittlung von Kenntnissen zur Betriebsfuhrung in sich im Ubergang befindlichen Wirtschaften ein raumlich aussiebender Vorgang ist, da die meisten strukturellen und Verhaltensfaktoren dazu neigen, Hauptstadtregionen zu begunstigen. Infolgedessen muss Ubergangspolitik ihrem Kerngehalt gewisse Formen der Regionalpolitik als erganzende und ausgleichende Kraft zu den vom Markt bestimmten strukturellen und raumlichen Einstellungen einverleiben.Enterprise Learning, Transition, Regional Policy,

Peripherality and integration: industrial growth and decline in the Greek regions

Peripheral European economies are often characterized by unfavorable structural regularities and geographical coordinates, making the process of economic integration an experience possibly associated with welfare losses at the regional level. Such types of arguments are at variance with the neoclassical understanding of the operation of the spatial economy, making the study of a weak industrial base in the EU periphery an interesting assignment with implications for theory and policy. We develop an empirical model accounting for industrial (manufacturing) growth and decline in the Greek regions in the period following EU membership (1981 2005). Given that Greek regions are characterized as lagging behind and structurally weak for the entire period under consideration, understanding the factors behind their industrial experience may have a value added for many regions with similar characteristics, especially in the new and potential EU member states