TY - JOUR AB - AbstractObjectiveConcerns about short‐ and long‐term consequences of repetitive heading contributed to heading restrictions in youth football in some countries. This prospective longitudinal cohort study aims to describe heading exposure in children's and youth football over two seasons using standardized video analysis.MethodsAll matches and training sessions of a male Under‐11 (n = 29), Under‐15 (n = 28), Under‐19 (n = 38), and female Under‐17 (n = 39) team were videotaped during the seasons 2019–2020 and 2020–2021. Heading frequencies and characteristics were analyzed. Individual heading exposure is presented as average incidence rates (IR) per 1000 match/training hours.ResultsIn 275 matches and 673 training sessions, 22 921 headers were observed. Heading IR per player in matches was 1256 (Under‐11 m), 1608 (Under‐15 m), 1050 (Under‐17 f), and 1966 (Under‐19 m). In training sessions, IR per player was 739 (Under‐11 m), 2206 (Under‐15 m), 1661 (Under‐17 f), and 1419 (Under‐19 m). Five Under‐15 males headed the ball five to eight times per training on average. Most headers were performed without heading duels. Flight distance was predominantly 5–20 m (54%) in matches and <5 m (65%) in training. While head impact location most frequently was at frontal areas, one‐third of all headers in Under‐11 in matches hit temporal, parietal, and occipital parts of the head.ConclusionHeading incidence was low in the youngest age group, whereas (predominantly five) Under‐15 males showed very high heading exposures in training. In assessment and regulation of heading burden, training sessions and individual heading behavior should specifically be addressed. Recommendations for heading the ball in practice should account for individual and age‐related differences. AU - Reeschke, Rebecca AU - Haase, Franziska Katharina AU - Dautzenberg, Lena AU - Krutsch, Werner AU - Reinsberger, Claus ID - 46818 IS - 9 JF - Scandinavian Journal of Medicine & Science in Sports KW - Physical Therapy KW - Sports Therapy and Rehabilitation KW - Orthopedics and Sports Medicine SN - 0905-7188 TI - Training matters: Heading incidence and characteristics in children's and youth football (soccer) players VL - 33 ER - TY - BOOK AU - Rossel, Moritz Sebastian AU - Meschut, Gerson ID - 46812 TI - Methodenentwicklung zur verbesserten Prognosegüte beim Clinchen mit beweglicher Matrize in der numerischen Fügeprozesssimulation VL - 598 ER - TY - JOUR AU - Höper, Lukas AU - Schulte, Carsten ID - 46186 IS - 4 JF - MNU journal SN - 0025-5866 TI - Paradigmenwechsel vom klassischen zum datengetriebenen Problemlösen im Informatikunterricht VL - 76 ER - TY - JOUR AU - Pfister, Daniel AU - Jackson, Robin C AU - Güldenpenning, Iris AU - Williams, A Mark ID - 46736 JF - Human Movement Science TI - Timing a fake punch: Inhibitory effects in a boxing-specific spatial attention task VL - 89 ER - TY - CONF AU - Blömer, Johannes AU - Bobolz, Jan AU - Bröcher, Henrik ID - 35014 TI - On the impossibility of surviving (iterated) deletion of weakly dominated strategies in rational MPC ER - TY - CONF AU - Blömer, Johannes AU - Bobolz, Jan AU - Porzenheim, Laurens Alexander ID - 43458 TI - A Generic Construction of an Anonymous Reputation System and Instantiations from Lattices ER - TY - CHAP AU - Schroeter-Wittke, Harald AU - Junkermann, Ilse ID - 46856 T2 - Ich lobe meinen Gott, der aus der Tiefe mich holt. Hymnologische Kommentare zu den Liedern im Ergänzungsheft zum Evangelischen Gesangbuch. Jan Janssen zum 60. Geburtstag. HEG 3/Ergänzungsheft, Göttingen 2023 TI - Stern über Bethlehem (EG.E 1) ER - TY - CHAP AU - Schroeter-Wittke, Harald ID - 46857 T2 - Ich lobe meinen Gott, der aus der Tiefe mich holt. Hymnologische Kommentare zu den Liedern im Ergänzungsheft zum Evangelischen Gesangbuch. Jan Janssen zum 60. Geburtstag. HEG 3/Ergänzungsheft, Göttingen 2023 TI - Wir haben Gottes Spuren festgestellt (EG.E 20) ER - TY - JOUR AB - In this work, the influence of the filler–matrix adhesion on the tensile properties of laser-sintered parts built with Polyamide 613 filled with glass beads was investigated. For this purpose, dry blends of glass beads with and without organosilane coupling agents and polyamide powder were prepared and processed into tensile specimens on an EOS P396 laser sintering system. The samples were tested both in the dry state and after an accelerated conditioning in a climate chamber. Furthermore, finite element method (FEM) simulations were performed to model the extreme cases of optimum adhesion and no adhesion. By correlating the tensile tests with the simulation results and by analyzing the fracture surfaces, it was shown that the filler–matrix adhesion is sufficient in the dry state but is strongly degraded by conditioning. Even the presence of various organosilane thin films could not prevent a strong deterioration of the filler–matrix adhesion and the associated deterioration of the mechanical properties. Since a comparison with an injection-molded sample of the same polymer filler combination shows identical behavior after conditioning, it is assumed that this problem is not limited to additively manufactured parts. AU - Kletetzka, Ivo AU - Kosanke, Maren AU - Meinderink, Dennis AU - Neßlinger, Vanessa AU - Grundmeier, Guido AU - Schmid, Hans-Joachim ID - 46815 JF - Progress in Additive Manufacturing KW - Industrial and Manufacturing Engineering SN - 2363-9512 TI - Influence of the filler–matrix adhesion and the effects of conditioning on tensile properties of laser-sintered parts built with polyamide–glass bead dry blends ER - TY - GEN AB - Abstract In this work, the influence of the filler matrix adhesion on the tensile properties of laser-sintered parts built with Polyamide 613 filled with glass beads was investigated. For this purpose, dry blends of glass beads with and without organosilane coupling agents and polyamide powder were prepared and processed into tensile specimens on an EOS P396. The samples were tested both in the dry state and after an accelerated conditioning in a climate chamber. Furthermore, FEM simulations were performed to model the limiting cases of optimum adhesion and no adhesion. By correlating the tensile tests with the simulation results and by analyzing the fracture surfaces, it was shown that the filler matrix adhesion is sufficient in the dry state but is strongly degraded by conditioning. Even the presence of various organosilane thin films could not prevent a strong deterioration of the filler-matrix adhesion and the associated deterioration of the mechanical properties. Since a comparison with an injection molded sample of the same polymer filler combination shows identical behavior after conditioning, it is assumed that this problem is not limited to additively manufactured parts. AU - Kletetzka, Ivo AU - Kosanke, Maren AU - Meinderink, Dennis AU - Neßlinger, Vanessa AU - Grundmeier, Guido AU - Schmid, Hans-Joachim ID - 43049 TI - Influence of the filler matrix adhesion and the effects of conditioning on tensile properties of laser sintered parts built with polyamide glass bead dry blends ER -