TY - THES A1 - Brigard Torres, Juan Camilo T1 - An aesthetic cartography of fast T1 - Eine ästhetische Kartographie des aktiven Hungers BT - Gandhi and the hunger artists BT - Gandhis Fasten und die Hungerkünstler*innen N2 - In this cartography, I examine M.K. Gandhi’s practice of fasting for political purposes from a specifically aesthetic perspective. In other words, to foreground their dramatic qualities, how they in their expressive repetition, patterning and stylization produced a/effected heightened forms of emotions. To carry out this task, I follow the theater scholar Erika Fischer-Lichte’s features that give name to her book Äesthetik des Performativen (2004). The cartography is framed in a philosophical presentation of Gandhi’s discourse as well as of his historical sources. Moreover, as a second frame, I historicize the fasts, by means of a typology and teleology in context. The historically and discoursively framed cartography maps four main dimensions that define the aesthetics of the performative: mediality, materiality, semioticity and aestheticity. The first part analyses the medial platforms in which the fasts as events have been historically recorded and in which they have left their traces and inscriptions. These historical sources are namely, newspapers, images, newsreels and a documentary film. Secondly, the material dimension depicts Gandhi’s corporeal condition, as well as the spatiality and temporality of the fasts. In the third place, I revise and reformulate critically Fischer-Lichte’s concepts of “presence” and “representation” with resonating concepts of G. C. Spivak and J. Rancière. This revision illustrates Gandhi’s fasts and shows the process of how an individual may become the embodiment or representation of a national body-politic. The last chapter of the cartography explores the autopoetic-feedback loop between Gandhi and the people and finishes with a comparison of the mise en scène of the hunger artists with the fasts of the Indian the politician, social reformer, and theologian. The text concludes interpreting Gandhi’s practice of fasting under the light of the concepts of “intellectual emancipation” and “de-subjectivation” of the philosopher J. Rancière. The four main concerns of this cartography are: Firstly, in the field of Gandhi’s reception, to explore the aesthetic dimension as both alternative and complementary to the two hegemonic interpretative lenses, i.e. a hagiographic or a secular political understanding of the fasts. From a theoretical perspective, the cartography pursues to be a transdisciplinary experiment that aims at deploying concepts that have been traditionally developed, derived from and used in the field of the arts (theater, film, literature, aesthetic performance, etc.) in the field of the political. In brief, inverting an expression of Rancière, to understand politics as aesthetics. Thirdly, from a thematic point of view, the cartography inquires the historical forms of staging and perception of hunger. Last yet importantly, it is an inquiry of the practice of fasting as nonviolence, what Gandhi, its most sophisticated modern theoretician and practitioner considered its most radical expression. N2 - Die Masterarbeit betrachtet M.K. Gandhis politische Ausübung des Fastens aus einer ästhetischen Perspektive. Im Fokus stehen dabei die dramatischen Eigenschaften dieser asketischen Praxis: Von besonderem Interesse sind expressive Wiederholungen, Gestaltungen und Stilisierungen, die Affekte auslösen. Die Analyse greift auf Begriffe und Theorien von Erika Fischer-Lichtes Ästhetik des Performativen (2004) zurück, um damit die ästhetische Dimension von Gandhis Fasten zu beleuchten. Eine historische und philosophische Kontextualisierung rahmt die ästhetische Kartographie ein. Die Analyse untergliedert sich in vier verschiedene Sphären: Medialität, Materialität, Semiotizität und Ästhetizität. Den Beginn macht eine Untersuchung von medialen Plattformen in den bereits historisierten Spuren der Ereignisse. Als historische Quellen dienen Zeitungsartikel, Fotos, die Wochenschau (newsreel) und ein Dokumentarfilm. Die Sphäre der Materialität wird im Anschluss durch die folgenden Kriterien analysiert: den körperlichen Zustand Gandhis, die Temporalität und die Räumlichkeit des Fastens. Zudem beschäftigt sich der Text mit der Konfiguration von Bedeutung durch eine theoretische Überarbeitung der von Fischer-Lichte geprägten Begriffe von „Präsenz“ und „Repräsentation“. Die Grundlage für diese Überarbeitung sind Texte von J. Rancière und G. C. Spivak. Die Überarbeitung soll mit Beispielen von Gandhis Fasten illustriert werden, um zu zeigen, wie ein individueller Mensch zur Verkörperung oder Repräsentation einer Nation werden kann. Zuletzt nimmt die Analyse der ästhetischen Sphäre die autopoietische Feedback-Schleife zwischen Gandhi und dem Volk in den Blick. Zudem vergleicht die Studie die Inszenierungsformen von Gandhis Fasten und die von den Hungerkünstlern*innen im Westen. Der Abschluss der Masterarbeit verbindet Gandhis Fasten als Ritual mit den von Jacques Rancière entwickelten Begriffen der intellektuellen Emanzipation und der De-Subjektivierung. KW - fasting KW - Gandhi KW - performance KW - aesthetics KW - Hunger KW - Fasten KW - Gandhi KW - Performance KW - Ästhetik KW - hunger Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469333 ER - TY - JOUR A1 - Ghahremani, Sona A1 - Giese, Holger T1 - Evaluation of self-healing systems BT - An analysis of the state-of-the-art and required improvements JF - Computers N2 - Evaluating the performance of self-adaptive systems is challenging due to their interactions with often highly dynamic environments. In the specific case of self-healing systems, the performance evaluations of self-healing approaches and their parameter tuning rely on the considered characteristics of failure occurrences and the resulting interactions with the self-healing actions. In this paper, we first study the state-of-the-art for evaluating the performances of self-healing systems by means of a systematic literature review. We provide a classification of different input types for such systems and analyse the limitations of each input type. A main finding is that the employed inputs are often not sophisticated regarding the considered characteristics for failure occurrences. To further study the impact of the identified limitations, we present experiments demonstrating that wrong assumptions regarding the characteristics of the failure occurrences can result in large performance prediction errors, disadvantageous design-time decisions concerning the selection of alternative self-healing approaches, and disadvantageous deployment-time decisions concerning parameter tuning. Furthermore, the experiments indicate that employing multiple alternative input characteristics can help with reducing the risk of premature disadvantageous design-time decisions. KW - self-healing KW - failure model KW - performance KW - simulation KW - evaluation Y1 - 2020 U6 - https://doi.org/10.3390/computers9010016 SN - 2073-431X VL - 9 IS - 1 PB - MDPI CY - Basel ER - TY - GEN A1 - Ghahremani, Sona A1 - Giese, Holger T1 - Performance evaluation for self-healing systems BT - Current Practice & Open Issues T2 - 2019 IEEE 4th International Workshops on Foundations and Applications of Self* Systems (FAS*W) N2 - Evaluating the performance of self-adaptive systems (SAS) is challenging due to their complexity and interaction with the often highly dynamic environment. In the context of self-healing systems (SHS), employing simulators has been shown to be the most dominant means for performance evaluation. Simulating a SHS also requires realistic fault injection scenarios. We study the state of the practice for evaluating the performance of SHS by means of a systematic literature review. We present the current practice and point out that a more thorough and careful treatment in evaluating the performance of SHS is required. KW - self-healing KW - failure profile KW - evaluation KW - simulator KW - performance Y1 - 2019 SN - 978-1-7281-2406-3 U6 - https://doi.org/10.1109/FAS-W.2019.00039 SP - 116 EP - 119 PB - IEEE CY - New York ER - TY - JOUR A1 - Ghahremani, Sona A1 - Giese, Holger A1 - Vogel, Thomas T1 - Improving scalability and reward of utility-driven self-healing for large dynamic architectures JF - ACM transactions on autonomous and adaptive systems N2 - Self-adaptation can be realized in various ways. Rule-based approaches prescribe the adaptation to be executed if the system or environment satisfies certain conditions. They result in scalable solutions but often with merely satisfying adaptation decisions. In contrast, utility-driven approaches determine optimal decisions by using an often costly optimization, which typically does not scale for large problems. We propose a rule-based and utility-driven adaptation scheme that achieves the benefits of both directions such that the adaptation decisions are optimal, whereas the computation scales by avoiding an expensive optimization. We use this adaptation scheme for architecture-based self-healing of large software systems. For this purpose, we define the utility for large dynamic architectures of such systems based on patterns that define issues the self-healing must address. Moreover, we use pattern-based adaptation rules to resolve these issues. Using a pattern-based scheme to define the utility and adaptation rules allows us to compute the impact of each rule application on the overall utility and to realize an incremental and efficient utility-driven self-healing. In addition to formally analyzing the computational effort and optimality of the proposed scheme, we thoroughly demonstrate its scalability and optimality in terms of reward in comparative experiments with a static rule-based approach as a baseline and a utility-driven approach using a constraint solver. These experiments are based on different failure profiles derived from real-world failure logs. We also investigate the impact of different failure profile characteristics on the scalability and reward to evaluate the robustness of the different approaches. KW - self-healing KW - adaptation rules KW - architecture-based adaptation KW - utility KW - reward KW - scalability KW - performance KW - failure profile model Y1 - 2020 U6 - https://doi.org/10.1145/3380965 SN - 1556-4665 SN - 1556-4703 VL - 14 IS - 3 PB - Association for Computing Machinery CY - New York ER - TY - THES A1 - Hesse, Günter T1 - A benchmark for enterprise stream processing architectures T1 - Ein Benchmark für Architekturen zur Datenstromverarbeitung im Unternehmenskontext N2 - Data stream processing systems (DSPSs) are a key enabler to integrate continuously generated data, such as sensor measurements, into enterprise applications. DSPSs allow to steadily analyze information from data streams, e.g., to monitor manufacturing processes and enable fast reactions to anomalous behavior. Moreover, DSPSs continuously filter, sample, and aggregate incoming streams of data, which reduces the data size, and thus data storage costs. The growing volumes of generated data have increased the demand for high-performance DSPSs, leading to a higher interest in these systems and to the development of new DSPSs. While having more DSPSs is favorable for users as it allows choosing the system that satisfies their requirements the most, it also introduces the challenge of identifying the most suitable DSPS regarding current needs as well as future demands. Having a solution to this challenge is important because replacements of DSPSs require the costly re-writing of applications if no abstraction layer is used for application development. However, quantifying performance differences between DSPSs is a difficult task. Existing benchmarks fail to integrate all core functionalities of DSPSs and lack tool support, which hinders objective result comparisons. Moreover, no current benchmark covers the combination of streaming data with existing structured business data, which is particularly relevant for companies. This thesis proposes a performance benchmark for enterprise stream processing called ESPBench. With enterprise stream processing, we refer to the combination of streaming and structured business data. Our benchmark design represents real-world scenarios and allows for an objective result comparison as well as scaling of data. The defined benchmark query set covers all core functionalities of DSPSs. The benchmark toolkit automates the entire benchmark process and provides important features, such as query result validation and a configurable data ingestion rate. To validate ESPBench and to ease the use of the benchmark, we propose an example implementation of the ESPBench queries leveraging the Apache Beam software development kit (SDK). The Apache Beam SDK is an abstraction layer designed for developing stream processing applications that is applied in academia as well as enterprise contexts. It allows to run the defined applications on any of the supported DSPSs. The performance impact of Apache Beam is studied in this dissertation as well. The results show that there is a significant influence that differs among DSPSs and stream processing applications. For validating ESPBench, we use the example implementation of the ESPBench queries developed using the Apache Beam SDK. We benchmark the implemented queries executed on three modern DSPSs: Apache Flink, Apache Spark Streaming, and Hazelcast Jet. The results of the study prove the functioning of ESPBench and its toolkit. ESPBench is capable of quantifying performance characteristics of DSPSs and of unveiling differences among systems. The benchmark proposed in this thesis covers all requirements to be applied in enterprise stream processing settings, and thus represents an improvement over the current state-of-the-art. N2 - Data Stream Processing Systems (DSPSs) sind eine Schlüsseltechnologie, um kontinuierlich generierte Daten, wie beispielsweise Sensormessungen, in Unternehmensanwendungen zu integrieren. Die durch DSPSs ermöglichte permanente Analyse von Datenströmen kann dabei zur Überwachung von Produktionsprozessen genutzt werden, um möglichst zeitnah auf ungewollte Veränderungen zu reagieren. Darüber hinaus filtern, sampeln und aggregieren DSPSs einkommende Daten, was die Datengröße reduziert und so auch etwaige Kosten für die Datenspeicherung. Steigende Datenvolumen haben in den letzten Jahren den Bedarf für performante DSPSs steigen lassen, was zur Entwicklung neuer DSPSs führte. Während eine große Auswahl an verfügbaren Systemen generell gut für Nutzer ist, stellt es potentielle Anwender auch vor die Herausforderung, das für aktuelle und zukünftige Anforderungen passendste DSPS zu identifizieren. Es ist wichtig, eine Lösung für diese Herausforderung zu haben, da das Austauschen von einem DSPS zu teuren Anpassungen oder Neuentwicklungen der darauf laufenden Anwendungen erfordert, falls für deren Entwicklung keine Abstraktionsschicht verwendet wurde. Das quantitative Vergleichen von DSPSs ist allerdings eine schwierige Aufgabe. Existierende Benchmarks decken nicht alle Kernfunktionalitäten von DSPSs ab und haben keinen oder unzureichenden Tool-Support, was eine objektive Ergebnisberechnung hinsichtlich der Performanz erschwert. Zudem beinhaltet kein Benchmark die Integration von Streamingdaten und strukturierten Geschäftsdaten, was ein besonders für Unternehmen relevantes Szenario ist. Diese Dissertation stellt ESPBench vor, einen neuen Benchmark für Stream Processing-Szenarien im Unternehmenskontext. Der geschäftliche Kontext wird dabei durch die Verbindung von Streamingdaten und Geschäftsdaten dargestellt. Das Design von ESPBench repräsentiert Szenarien der realen Welt, stellt die objektive Berechnung von Benchmarkergebnissen sicher und erlaubt das Skalieren über Datencharakteristiken. Das entwickelte Toolkit des Benchmarks stellt wichtige Funktionalitäten bereit, wie beispielsweise die Automatisierung den kompletten Benchmarkprozesses sowie die Überprüfung der Abfrageergebnisse hinsichtlich ihrer Korrektheit. Um ESPBench zu validieren und die Anwendung weiter zu vereinfachen, haben wir eine Beispielimplementierung der Queries veröffentlicht. Die Implementierung haben wir mithilfe des in Industrie und Wissenschaft eingesetzten Softwareentwicklungsbaukastens Apache Beam durchgeführt, der es ermöglicht, entwickelte Anwendungen auf allen unterstützten DSPSs auszuführen. Den Einfluss auf die Performanz des Verwendens von Apache Beam wird dabei ebenfalls in dieser Arbeit untersucht. Weiterhin nutzen wir die veröffentlichte Beispielimplementierung der Queries um drei moderne DSPSs mit ESPBench zu untersuchen: Apache Flink, Apache Spark Streaming und Hazelcast Jet. Der Ergebnisse der Studie verdeutlichen die Funktionsfähigkeit von ESPBench und dessen Toolkit. ESPBench befähigt Performanzcharakteristiken von DSPSs zu quantifizieren und Unterschiede zwischen Systemen aufzuzeigen. Der in dieser Dissertation vorgestellte Benchmark erfüllt alle Anforderungen, um in Stream Processing-Szenarien im Unternehmenskontext eingesetzt zu werden und stellt somit eine Verbesserung der aktuellen Situation dar. KW - stream processing KW - performance KW - benchmarking KW - dsps KW - espbench KW - benchmark KW - Performanz KW - Datenstromverarbeitung KW - Benchmark Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-566000 ER - TY - JOUR A1 - Islam, Khan M. Shaiful A1 - Schaeublin, H. A1 - Wenk, C. A1 - Wanner, Michael A1 - Liesegang, Annette T1 - Effect of dietary citric acid on the performance and mineral metabolism of broiler JF - Journal of animal physiology and animal nutrition N2 - The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone-breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps (R), Ca, P, Mg and 1,25(OH)(2)Vit-D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA-fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA-fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance, feed conversion efficiency, carcass weight and carcass quality, but only in numerical terms. The addition of CA up to 0.75% significantly increased the digestibility of macro minerals, bone ash content, bone mineral density and bone strength of the broiler chicks. It may, therefore, be concluded that the addition of 0.75% CA in a standard diet is suitable for growth, carcass traits, macromineral digestibility and bone mineral density of broiler chicks. KW - broiler chicks KW - dietary citric acid KW - calcium KW - phosphorus KW - metabolism KW - performance Y1 - 2012 U6 - https://doi.org/10.1111/j.1439-0396.2011.01225.x SN - 0931-2439 VL - 96 IS - 5 SP - 808 EP - 817 PB - Wiley-Blackwell CY - Hoboken ER - TY - GEN A1 - Kearney, Eric A1 - Razinskas, Stefan A1 - Weiss, Matthias A1 - Hoegl, Martin T1 - Gender diversity and team performance under time pressure BT - The role of team withdrawal and information elaboration T2 - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe N2 - Findings in the extant literature are mixed concerning when and how gender diversity benefits team performance. We develop and test a model that posits that gender-diverse teams outperform gender-homogeneous teams when perceived time pressure is low, whereas the opposite is the case when perceived time pressure is high. Drawing on the categorization-elaboration model (CEM; van Knippenberg, De Dreu, & Homan, 2004), we begin with the assumption that information elaboration is the process whereby gender diversity fosters positive effects on team performance. However, also in line with the CEM, we argue that this process can be disrupted by adverse team dynamics. Specifically, we argue that as time pressure increases, higher gender diversity leads to more team withdrawal, which, in turn, moderates the positive indirect effect of gender diversity on team performance via information elaboration such that this effect becomes weaker as team withdrawal increases. In an experimental study of 142 four-person teams, we found support for this model that explains why perceived time pressure affects the performance of gender-diverse teams more negatively than that of gender-homogeneous teams. Our study sheds new light on when and how gender diversity can become either an asset or a liability for team performance. T3 - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe - 189 KW - gender diversity KW - information elaboration KW - perceived time pressure KW - team KW - performance KW - team withdrawal Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-606559 SN - 1867-5808 IS - 7 ER - TY - JOUR A1 - Kearney, Eric A1 - Razinskas, Stefan A1 - Weiss, Matthias A1 - Hoegl, Martin T1 - Gender diversity and team performance under time pressure BT - the role of team withdrawal and information elaboration JF - Journal of organizational behavior N2 - Findings in the extant literature are mixed concerning when and how gender diversity benefits team performance. We develop and test a model that posits that gender-diverse teams outperform gender-homogeneous teams when perceived time pressure is low, whereas the opposite is the case when perceived time pressure is high. Drawing on the categorization-elaboration model (CEM; van Knippenberg, De Dreu, & Homan, 2004), we begin with the assumption that information elaboration is the process whereby gender diversity fosters positive effects on team performance. However, also in line with the CEM, we argue that this process can be disrupted by adverse team dynamics. Specifically, we argue that as time pressure increases, higher gender diversity leads to more team withdrawal, which, in turn, moderates the positive indirect effect of gender diversity on team performance via information elaboration such that this effect becomes weaker as team withdrawal increases. In an experimental study of 142 four-person teams, we found support for this model that explains why perceived time pressure affects the performance of gender-diverse teams more negatively than that of gender-homogeneous teams. Our study sheds new light on when and how gender diversity can become either an asset or a liability for team performance. KW - gender diversity KW - information elaboration KW - perceived time pressure KW - team KW - performance KW - team withdrawal Y1 - 2022 U6 - https://doi.org/10.1002/job.2630 SN - 0894-3796 SN - 1099-1379 VL - 43 IS - 7 SP - 1224 EP - 1239 PB - Wiley CY - Hoboken ER - TY - THES A1 - Kroll, Alexander T1 - Why public managers use performance information : concepts, theory, and empirical analysis T1 - Warum Verwaltungsmanager Performance-Informationen nutzen : Konzepte, Theorien und Empirische Analyse N2 - Diese Dissertation untersucht die Verwendung von Performance-Informationen („Kennzahlen“) durch Führungskräfte in der öffentlichen Verwaltung. Unter „Verwendung“ wird dabei die zweckorientierte Nutzung der Daten verstanden, um zu steuern, zu lernen und öffentliche Leistungen zu verbessern. Die zentrale Frage der Arbeit lautet: Wie können Unterschiede bei der Verwendung von Performance-Informationen erklärt werden? Um diese Frage zu beantworten, wird die bereits existierende Literatur strukturiert ausgewertet. Forschungslücken werden aufgezeigt und eigene Ansätze vorgestellt, wie diese geschlossen werden können. Der erste Teil der Dissertation untersucht den Einfluss von Manager-bezogenen Faktoren auf die Nutzung von Performance-Daten, die bislang in der Forschung noch keine Berücksichtigung gefunden haben. Der zweite Abschnitt testet ein modifiziertes Modell aus der Psychologie, das auf der Annahme basiert, dass die Verwendung von Performance-Informationen ein bewusstes und durchdachtes Verhalten darstellt. Der dritte Teil untersucht, inwieweit sich die Erklärungen für die Nutzung von Performance-Informationen unterscheiden, wenn wir diese nicht nur als Kennzahlen definieren, sondern ebenfalls andere Quellen von „unsystematischem“ Feedback berücksichtigen. Die empirischen Ergebnisse der Arbeit basieren auf einer Umfrage aus dem Jahr 2011. Im Rahmen dieses Surveys habe ich die mittleren Manager (Amtsleiter und Fachbereichsleiter) aus acht ausgewählten Bereichen aller kreisfreien Städte in Deutschland befragt (n=954). Zur Auswertung der Daten wurden die Verfahren Faktorenanalyse, Multiple Regressionsanalyse und Strukturgleichungsmodellierung eingesetzt. Meine Forschung förderte unter anderem vier Erkenntnisse zu Tage, die durch ähnliche Befunde der verschiedenen Teile der Dissertation abgesichert sind: 1) Die Verwendung von Performance-Daten kann als bewusstes Verhalten von Führungskräften modelliert werden, das durch deren Einstellung sowie durch die Einstellung ihres sozialen Umfeldes bestimmt wird. 2) Häufige Nutzer von Performance-Informationen zeigen überraschenderweise keine generelle Präferenz für das abstrakt-analytische Verarbeiten von Informationen. Stattdessen bevorzugen sie, Informationen durch persönliche Interaktionen aufzunehmen. 3) Manager, die sich früh im Rahmen der Ermittlung von Performance-Informationen engagieren, nutzen diese später auch häufiger, um Entscheidungen zu treffen. 4) Performance-Berichte sind nur eine Informationsquelle unter vielen. Verwaltungsmanager präferieren verbales Feedback von Insidern sowie das Feedback von wichtigen externen Stakeholdern gegenüber systematischen Performance-Daten. Die Dissertation erklärt diese Befunde theoretisch und verdeutlicht deren Implikationen für Theorie und Praxis. N2 - The dissertation examines the use of performance information by public managers. “Use” is conceptualized as purposeful utilization in order to steer, learn, and improve public services. The main research question is: Why do public managers use performance information? To answer this question, I systematically review the existing literature, identify research gaps and introduce the approach of my dissertation. The first part deals with manager-related variables that might affect performance information use but which have thus far been disregarded. The second part models performance data use by applying a theory from social psychology which is based on the assumption that this management behavior is conscious and reasoned. The third part examines the extent to which explanations of performance information use vary if we include others sources of “unsystematic” feedback in our analysis. The empirical results are based on survey data from 2011. I surveyed middle managers from eight selected divisions of all German cities with county status (n=954). To analyze the data, I used factor analysis, multiple regression analysis, and structural equation modeling. My research resulted in four major findings: 1) The use of performance information can be modeled as a reasoned behavior which is determined by the attitude of the managers and of their immediate peers. 2) Regular users of performance data surprisingly are not generally inclined to analyze abstract data but rather prefer gathering information through personal interaction. 3) Managers who take on ownership of performance information at an early stage in the measurement process are also more likely to use this data when it is reported to them. 4) Performance reports are only one source of information among many. Public managers prefer verbal feedback from insiders and feedback from external stakeholders over systematic performance reports. The dissertation explains these findings using a deductive approach and discusses their implications for theory and practice. KW - Performance KW - Datenverwendung KW - Performance-Informationen KW - Performance Management KW - performance KW - data use KW - performance information KW - performance management Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59795 ER - TY - GEN A1 - Kuik, Friderike A1 - Lauer, Axel A1 - Churkina, Galina A1 - Denier Van der Gon, Hugo Anne Cornelis A1 - Fenner, Daniel A1 - Mar, Kathleen A. A1 - Butler, Tim M. T1 - Air quality modelling in the Berlin–Brandenburg region using WRF-Chem v3.7.1 BT - sensitivity to resolution of model grid and input data T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Air pollution is the number one environmental cause of premature deaths in Europe. Despite extensive regulations, air pollution remains a challenge, especially in urban areas. For studying summertime air quality in the Berlin-Brandenburg region of Germany, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) is set up and evaluated against meteorological and air quality observations from monitoring stations as well as from a field campaign conducted in 2014. The objective is to assess which resolution and level of detail in the input data is needed for simulating urban background air pollutant concentrations and their spatial distribution in the Berlin-Brandenburg area. The model setup includes three nested domains with horizontal resolutions of 15, 3 and 1 km and anthropogenic emissions from the TNO-MACC III inventory. We use RADM2 chemistry and the MADE/SORGAM aerosol scheme. Three sensitivity simulations are conducted updating input parameters to the single-layer urban canopy model based on structural data for Berlin, specifying land use classes on a sub-grid scale (mosaic option) and downscaling the original emissions to a resolution of ca. 1 km x 1 km for Berlin based on proxy data including traffic density and population density. The results show that the model simulates meteorology well, though urban 2m temperature and urban wind speeds are biased high and nighttime mixing layer height is biased low in the base run with the settings described above. We show that the simulation of urban meteorology can be improved when specifying the input parameters to the urban model, and to a lesser extent when using the mosaic option. On average, ozone is simulated reasonably well, but maximum daily 8 h mean concentrations are underestimated, which is consistent with the results from previous modelling studies using the RADM2 chemical mechanism. Particulate matter is underestimated, which is partly due to an underestimation of secondary organic aerosols. NOx (NO + NO2) concentrations are simulated reasonably well on average, but nighttime concentrations are overestimated due to the model's underestimation of the mixing layer height, and urban daytime concentrations are underestimated. The daytime underestimation is improved when using downscaled, and thus locally higher emissions, suggesting that part of this bias is due to deficiencies in the emission input data and their resolution. The results further demonstrate that a horizontal resolution of 3 km improves the results and spatial representativeness of the model compared to a horizontal resolution of 15 km. With the input data (land use classes, emissions) at the level of detail of the base run of this study, we find that a horizontal resolution of 1 km does not improve the results compared to a resolution of 3 km. However, our results suggest that a 1 km horizontal model resolution could enable a detailed simulation of local pollution patterns in the Berlin-Brandenburg region if the urban land use classes, together with the respective input parameters to the urban canopy model, are specified with a higher level of detail and if urban emissions of higher spatial resolution are used. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 531 KW - urban canopy model KW - aqmeii phase-2 KW - Mexico-City KW - Heat-Island KW - ozone KW - performance KW - transport KW - chemistry KW - meteorology KW - simulation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410131 SN - 1866-8372 IS - 531 ER - TY - JOUR A1 - Lampart, Fabian T1 - Form and Content, Again BT - four remarks on lyric theory JF - Journal of Literary Theory N2 - The following statement suggests reconsidering recent debates on a theory of lyric in terms of form and content. Four aspects and issues of the ongoing debate are discussed. In a first step, it is necessary to establish the relation between authorial poetics and lyric theory, since it is often characterised by fuzzy boundaries. Secondly, in order to specify the problem of form in lyric theory, it is suggested to have a closer look at the performative in lyric practice. Another important aspect of form is the semantics of lyrical genres. Lyrical genres mark an area in which form and content are intertwined and in which aspects of the form itself become semantic. Finally, the author argues that we should discuss - if possible assisted by a didactics sensitive to literary texts - whether and how theoretical proposals could be transformed into a practice of teaching poetry. KW - lyric KW - form KW - content KW - poetry and poetics KW - performance KW - teaching poetry Y1 - 2017 U6 - https://doi.org/10.1515/jlt-2017-0008 SN - 1862-5290 SN - 1862-8990 VL - 11 IS - 1 SP - 74 EP - 82 PB - De Gruyter CY - Berlin ER - TY - GEN A1 - Lesinski, Melanie A1 - Schmelcher, Alina A1 - Herz, Michael A1 - Puta, Christian A1 - Gabriel, Holger A1 - Arampatzis, Adamantios A1 - Laube, Gunnar A1 - Büsch, Dirk A1 - Granacher, Urs T1 - Maturation-, age-, and sex-specific anthropometric and physical fitness percentiles of German elite young athletes T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The aim of this study was to establish maturation-, age-, and sex-specific anthropometric and physical fitness percentile reference values of young elite athletes from various sports. Anthropometric (i.e., standing and sitting body height, body mass, body mass index) and physical fitness (i.e., countermovement jump, drop jump, change-of-direction speed [i.e., T-test], trunk muscle endurance [i.e., ventral Bourban test], dynamic lower limbs balance [i.e., Y-balance test], hand grip strength) of 703 male and female elite young athletes aged 8–18 years were collected to aggregate reference values according to maturation, age, and sex. Findings indicate that body height and mass were significantly higher (p<0.001; 0.95≤d≤1.74) in more compared to less mature young athletes as well as with increasing chronological age (p<0.05; 0.66≤d≤3.13). Furthermore, male young athletes were significantly taller and heavier compared to their female counterparts (p<0.001; 0.34≤d≤0.50). In terms of physical fitness, post-pubertal athletes showed better countermovement jump, drop jump, change-of-direction, and handgrip strength performances (p<0.001; 1.57≤d≤8.72) compared to pubertal athletes. Further, countermovement jump, drop jump, change-of-direction, and handgrip strength performances increased with increasing chronological age (p<0.05; 0.29≤d≤4.13). In addition, male athletes outperformed their female counterpart in the countermovement jump, drop jump, change-of-direction, and handgrip strength (p<0.05; 0.17≤d≤0.76). Significant age by sex interactions indicate that sex-specific differences were even more pronounced with increasing age. Conclusively, body height, body mass, and physical fitness increased with increasing maturational status and chronological age. Sex-specific differences appear to be larger as youth grow older. Practitioners can use the percentile values as approximate benchmarks for talent identification and development. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 662 KW - biological maturation KW - reliability KW - validity KW - performance KW - physiology KW - maturity KW - injury KW - talent Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-480268 SN - 1866-8364 IS - 662 ER - TY - JOUR A1 - Lesinski, Melanie A1 - Schmelcher, Alina A1 - Herz, Michael A1 - Puta, Christian A1 - Gabriel, Holger A1 - Arampatzis, Adamantios A1 - Laube, Gunnar A1 - Büsch, Dirk A1 - Granacher, Urs T1 - Maturation-, age-, and sex-specific anthropometric and physical fitness percentiles of German elite young athletes JF - Plos One N2 - The aim of this study was to establish maturation-, age-, and sex-specific anthropometric and physical fitness percentile reference values of young elite athletes from various sports. Anthropometric (i.e., standing and sitting body height, body mass, body mass index) and physical fitness (i.e., countermovement jump, drop jump, change-of-direction speed [i.e., T-test], trunk muscle endurance [i.e., ventral Bourban test], dynamic lower limbs balance [i.e., Y-balance test], hand grip strength) of 703 male and female elite young athletes aged 8–18 years were collected to aggregate reference values according to maturation, age, and sex. Findings indicate that body height and mass were significantly higher (p<0.001; 0.95≤d≤1.74) in more compared to less mature young athletes as well as with increasing chronological age (p<0.05; 0.66≤d≤3.13). Furthermore, male young athletes were significantly taller and heavier compared to their female counterparts (p<0.001; 0.34≤d≤0.50). In terms of physical fitness, post-pubertal athletes showed better countermovement jump, drop jump, change-of-direction, and handgrip strength performances (p<0.001; 1.57≤d≤8.72) compared to pubertal athletes. Further, countermovement jump, drop jump, change-of-direction, and handgrip strength performances increased with increasing chronological age (p<0.05; 0.29≤d≤4.13). In addition, male athletes outperformed their female counterpart in the countermovement jump, drop jump, change-of-direction, and handgrip strength (p<0.05; 0.17≤d≤0.76). Significant age by sex interactions indicate that sex-specific differences were even more pronounced with increasing age. Conclusively, body height, body mass, and physical fitness increased with increasing maturational status and chronological age. Sex-specific differences appear to be larger as youth grow older. Practitioners can use the percentile values as approximate benchmarks for talent identification and development. KW - biological maturation KW - reliability KW - validity KW - performance KW - physiology KW - maturity KW - injury KW - talent Y1 - 2020 U6 - https://doi.org/10.1371/journal.pone.0237423 SN - 1932-6203 VL - 15 IS - 8 PB - Plos One CY - San Francisco, California ER - TY - GEN A1 - Moser, Othmar A1 - Tschakert, Gerhard A1 - Mueller, Alexander A1 - Groeschl, Werner A1 - Pieber, Thomas R. A1 - Obermayer-Pietsch, Barbara A1 - Koehler, Gerd A1 - Hofmann, Peter T1 - Effects of high-intensity interval exercise versus moderate continuous exercise on glucose homeostasis and hormone response in patients with type 1 diabetes mellitus using novel ultra-long-acting insulin T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Introduction We investigated blood glucose (BG) and hormone response to aerobic high-intensity interval exercise (HIIE) and moderate continuous exercise (CON) matched for mean load and duration in type 1 diabetes mellitus (T1DM). Material and Methods Seven trained male subjects with T1DM performed a maximal incremental exercise test and HIIE and CON at 3 different mean intensities below (A) and above (B) the first lactate turn point and below the second lactate turn point (C) on a cycle ergometer. Subjects were adjusted to ultra-long-acting insulin Degludec (Tresiba/Novo Nordisk, Denmark). Before exercise, standardized meals were administered, and short-acting insulin dose was reduced by 25% (A), 50% (B), and 75% (C) dependent on mean exercise intensity. During exercise, BG, adrenaline, noradrenaline, dopamine, cortisol, glucagon, and insulin-like growth factor-1, blood lactate, heart rate, and gas exchange variables were measured. For 24 h after exercise, interstitial glucose was measured by continuous glucose monitoring system. Results BG decrease during HIIE was significantly smaller for B (p = 0.024) and tended to be smaller for A and C compared to CON. No differences were found for post-exercise interstitial glucose, acute hormone response, and carbohydrate utilization between HIIE and CON for A, B, and C. In HIIE, blood lactate for A (p = 0.006) and B (p = 0.004) and respiratory exchange ratio for A (p = 0.003) and B (p = 0.003) were significantly higher compared to CON but not for C. Conclusion Hypoglycemia did not occur during or after HIIE and CON when using ultra-long-acting insulin and applying our methodological approach for exercise prescription. HIIE led to a smaller BG decrease compared to CON, although both exercises modes were matched for mean load and duration, even despite markedly higher peak workloads applied in HIIE. Therefore, HIIE and CON could be safely performed in T1DM. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 497 KW - target heart-rate KW - failure KW - recommendations KW - hypoglycemia KW - individuals KW - performance KW - risk Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408342 SN - 1866-8364 IS - 497 ER - TY - JOUR A1 - Mugele, Hendrik A1 - Plummer, Ashley A1 - Baritello, Omar A1 - Towe, Maggie A1 - Brecht, Pia A1 - Mayer, Frank T1 - Accuracy of training recommendations based on a treadmill multistage incremental exercise test JF - PLOS ONE N2 - Competitive runners will occasionally undergo exercise in a laboratory setting to obtain predictive and prescriptive information regarding their performance. The present research aimed to assess whether the physiological demands of lab-based treadmill running (TM) can simulate that of over-ground (OG) running using a commonly used protocol. Fifteen healthy volunteers with a weekly mileage of ≥ 20 km over the past 6 months and treadmill experience participated in this cross-sectional study. Two stepwise incremental tests until volitional exhaustion was performed in a fixed order within one week in an Outpatient Clinic research laboratory and outdoor athletic track. Running velocity (IATspeed), heart rate (IATHR) and lactate concentration at the individual anaerobic threshold (IATbLa) were primary endpoints. Additionally, distance covered (DIST), maximal heart rate (HRmax), maximal blood lactate concentration (bLamax) and rate of perceived exertion (RPE) at IATspeed were analyzed. IATspeed, DIST and HRmax were not statistically significantly different between conditions, whereas bLamax and RPE at IATspeed showed statistical significance (p < 0.05). Apart from RPE at IATspeed, IATspeed, DIST, HRmax and bLamax strongly correlate between conditions (r = 0.815–0.988). High reliability between conditions provides strong evidence to suggest that running on a treadmill are physiologically comparable to that of OG and that training recommendations and be made with assurance. KW - individual anaerobic threshold KW - lactate threshold KW - soccer players KW - performance KW - validity KW - reliability KW - runners Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0204696 SN - 1932-6203 VL - 13 IS - 10 SP - 1 EP - 12 PB - PLOS CY - San Francisco ER - TY - GEN A1 - Mugele, Hendrik A1 - Plummer, Ashley A1 - Baritello, Omar A1 - Towe, Maggie A1 - Brecht, Pia A1 - Mayer, Frank T1 - Accuracy of training recommendations based on a treadmill multistage incremental exercise test T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Competitive runners will occasionally undergo exercise in a laboratory setting to obtain predictive and prescriptive information regarding their performance. The present research aimed to assess whether the physiological demands of lab-based treadmill running (TM) can simulate that of over-ground (OG) running using a commonly used protocol. Fifteen healthy volunteers with a weekly mileage of ≥ 20 km over the past 6 months and treadmill experience participated in this cross-sectional study. Two stepwise incremental tests until volitional exhaustion was performed in a fixed order within one week in an Outpatient Clinic research laboratory and outdoor athletic track. Running velocity (IATspeed), heart rate (IATHR) and lactate concentration at the individual anaerobic threshold (IATbLa) were primary endpoints. Additionally, distance covered (DIST), maximal heart rate (HRmax), maximal blood lactate concentration (bLamax) and rate of perceived exertion (RPE) at IATspeed were analyzed. IATspeed, DIST and HRmax were not statistically significantly different between conditions, whereas bLamax and RPE at IATspeed showed statistical significance (p < 0.05). Apart from RPE at IATspeed, IATspeed, DIST, HRmax and bLamax strongly correlate between conditions (r = 0.815–0.988). High reliability between conditions provides strong evidence to suggest that running on a treadmill are physiologically comparable to that of OG and that training recommendations and be made with assurance. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 477 KW - individual anaerobic threshold KW - lactate threshold KW - soccer players KW - performance KW - validity KW - reliability KW - runners Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419697 SN - 1866-8364 IS - 477 ER - TY - JOUR A1 - Musalek, Martin A1 - Kokstejn, Jakub A1 - Papez, Pavel A1 - Scheffler, Christiane A1 - Mumm, Rebekka A1 - Czernitzki, Anna-Franziska A1 - Koziel, Slawomir T1 - Impact of normal weight obesity on fundamental motor skills in pre-school children aged 3 to 6 years JF - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Normal weight obesity is defined as having excessive body fat, but normal BMI. Even though previous research revealed that excessive body fat in children inhibited their physical activity and decreased motor performance, there has been only little evidence about motor performance of normal weight obese children. This study aims to establish whether normal weight obese pre-school children aged 3-6 years will have a significantly worse level of fundamental motor skills compared to normal weight non-obese counterparts. The research sample consisted of 152 pre-schoolers selected from a specific district of Prague, the Czech Republic. According to values from four skinfolds: triceps, subscapula, suprailiaca, calf, and BMI three categories of children aged 3-6 years were determined: A) normal weight obese n = 51; B) normal weight non-obese n = 52; C) overweight and obese n = 49. The Movement Assessment Battery for Children (MABC-2) was used for the assessment of fundamental motor skills. Normal weight obese children had significantly higher amount of adipose tissue p < 0.001 than normal weight non-obese children but the same average BMI. Moreover, normal weight obese children did not have significantly less amount of subcutaneous fat on triceps and calf compared to their overweight and obese peers. In majority of MABC-2 tests, normal weight obese pre-schoolers showed the poorest performance. Moreover, normal weight obese children had significantly worse total standard score = 38.82 compared to normal weight non-obese peers = 52.27; p < 0.05. In addition, normal weight obese children had a more than three times higher frequency OR = 3.69 CI95% (1.10; 12.35) of severe motor deficit performance <= 5th centile of the MABC-2 norm. These findings are strongly alarming since indices like BMI are not able to identify normal weight obese individual. We recommend verifying real portion of normal weight obese children as they are probably in higher risk of health and motor problems than overweight and obese population due to their low lean mass. KW - normal weight obesity KW - fundamental motor skills KW - MABC-2 KW - performance KW - pre-school children KW - skinfolds KW - adipose tissue KW - lean mass Y1 - 2017 U6 - https://doi.org/10.1127/anthranz/2017/0752 SN - 0003-5548 VL - 74 SP - 203 EP - 212 PB - Schweizerbart CY - Stuttgart ER - TY - GEN A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain N2 - In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3–1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 319 KW - SEMG-pattern KW - back pain KW - drop jump KW - neuromuscular KW - performance KW - pre-activity KW - trunk KW - young athletes Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-395261 ER - TY - JOUR A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain JF - Frontiers in physiology N2 - In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3–1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment. KW - SEMG-pattern KW - back pain KW - pre-activity KW - drop jump KW - neuromuscular KW - trunk KW - performance KW - young athletes Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00274 SN - 1664-042X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Mueller, Juliane A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain JF - Frontiers in physiology N2 - In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 +/- 1.3 y; 176 +/- 11 cm; 68 +/- 11 kg; 12.4 +/- 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 +/- 1.3 y; 174 +/- 7 cm; 67 +/- 8 kg; 14.9 +/- 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized toMIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment. KW - SEMG-pattern KW - back pain KW - pre-activity KW - drop jump KW - neuromuscular KW - trunk KW - performance KW - young athletes Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00274 SN - 1664-042X VL - 8 SP - 124 EP - 132 PB - Frontiers Research Foundation CY - Lausanne ER -