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REN Xiang-yang MUELLER Heinrich KUHLENKOETTER Bernd 《浙江大学学报(A卷英文版)》2006,7(7):1215-1224
INTRODUCTION The simulation and verification technologies of numerical controlled (NC) manufacturing processes have been developed since the end of the 1970s, and a lot of significant accomplishments have been achieved. This kind of technology has important im- pact on product development and quality control. The designed CAD model can be produced to virtually reduce or even eliminate expensive experiments on testing material. If any potential problem, such as collision, improper parame… 相似文献
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Heinrich William F. Louson Eleanor Blommel Caroline Green Aalayna R. 《Innovative Higher Education》2021,46(3):357-375
Innovative Higher Education - This study explores a case of coaching deployed in experiential, interdisciplinary, and project-based courses. This study follows coaching in two courses that operated... 相似文献
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Robert Eberle Dieter Heinrich Peter Kaps Michael Oberguggenberger Werner Nachbauer 《Journal of sports sciences》2017,35(12):1125-1133
A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model. Injury prone situations for ACL-injuries were generated by the musculoskeletal simulation model using measured kinematics of a non-injury situation and the method of Monte Carlo simulation. Subsequently, the SBRS was varied for injury prone landings. The maximal ACL tensile forces and contributing factors to the ACL forces were compared for the different SBRS. In the injury prone landings the maximal ACL tensile forces increased with increasing SBRS. It was found that the higher maximal ACL force was caused by higher forces acting on the tibia by the boot and by higher quadriceps muscle forces both due to the higher SBRS. Practical experience suggested that the reduction of SBRS is not accepted by ski racers due to performance reasons. Thus, preventive measures may concentrate on the reduction of the quadriceps muscle force during impact. 相似文献
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Activation of the hamstrings has been discussed as a measure for reducing strain on the ACL during jump landings in alpine skiing. The current study tested the hypothesis that hamstring and quadriceps activation can be voluntarily increased by the athlete. Specifically, two different instructions – to increase hamstring activation or to increase upper-leg co-contraction – were compared to normal landings. Eight members of the German national and junior national squad in freestyle skiing (age 19.6 ± 3.8 years; weight 66.1 ± 13.2 kg; height 172.2 ± 7.7 cm) performed 12 jump landings on a prepared run, 4 with no specific instruction, 4 with the instruction to generally activate the thigh muscles, and 4 with the instruction to specifically activate the hamstrings. Electromyographic (EMG) signals were recorded on the biceps femoris (BF), semitendinosus (ST), vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). EMG activation levels were integrated over three landing phases and analysed with a repeated measures ANOVA. The instruction produced a significant main effect in ST (p = .026), VM (p = .032) and RF (p = .001). Contrary to previous research, the current study suggests that hamstring muscle activation levels can be voluntarily increased during jump landing, particularly in co-activation with its antagonists. 相似文献
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Vogt S Schumacher YO Blum A Roecker K Dickhuth HH Schmid A Heinrich L 《Journal of sports sciences》2007,25(12):1299-1305
Until recently, the physiological demands of cycling competitions were mostly reflected by the measurement of heart rate and the indirect estimation of exercise intensity. The purpose of this case study was to illustrate the varying power output of a professional cyclist during flat and mountain stages of a Grand Tour (Giro d'Italia). Nine stage recordings of a cyclist of the 2005 Giro d'Italia were monitored using a mobile power measurement device (SRM Trainingssystem, Julich, Germany), which recorded direct power output and heart rate. Stages were categorized into flat (n = 5) and mountain stages (n = 4). Data were processed electronically, and the overall mean power in flat and mountain stages and maximal mean power for various durations were calculated. Mean power output was 132 W +/- 26 (2.0 W x kg(-1) +/- 0.4) for the flat and 235 W +/- 10 (3.5 W x kg(-1) +/- 0.1) for the mountain stages. Mountain stages showed higher maximal mean power (367 W) for longer durations (1800 s) than flat stages (239 W). Flat stages are characterized by a large variability of power output with short bursts of high power and long periods with reduced intensity of exercise, whereas mountain stages mostly require submaximal, constant power output over longer periods. 相似文献
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Sinai Ucko Gert Otto M. J. Langeveld H. H. Stern Oskar Anweiler C. H. Dobinson Helmut Meyer-Bothling Jürgen Zabeck Heinrich Abel Hans Kirchhoff Rudolf Haas Heinrich Roth Lotte Schenk-Danzinger J. M. Tanner Barbara Magierska 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1962,7(4):487-510