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Jacobo Ángel Rubio-Arias Domingo Jesús Ramos-Campo Paula Esteban Fernando Martínez José Fernando Jiménez 《Journal of sports sciences》2018,36(4):398-406
The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EGWBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg?1; P = 0.001), take-off velocity (0.1 cm · s?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EGWBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EGWBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men. 相似文献
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ABSTRACTWhat makes a good teacher and what motivates a person to want to teach are timeless questions that concern us all. This study focuses on those who are currently training to become teachers, more specifically undergraduates studying a degree in Primary Education in the universities of Catalonia. It adopts a quantitative methodology based on a self-administered questionnaire conducted with a representative sample. Participants’ open-ended responses are recorded and codified. Three main categories are constructed: personal, authentic teacher; the teacher as story teller; and, the teacher as motivator of learning. Results highlight important differences between these categories, extolling above all the authentic, personal teacher, who leaves a mark thanks to their character and way of being. This, together with other findings, raises various considerations for the university training of future teachers. 相似文献
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ResumenEn este trabajo se estudia la diferencia entre los sexos en la resolución de problemas aritméticos verbales. Participaron 1.078 escolares de los grados 3.°, 4.°, 5.°, 6.° y 8.° de E.G.B. Se aplicó una prueba de 17 problemas aritméticos a los escolares de 3°, 4° y 5° en dos sesiones. También se aplicó una prueba de 4 problemas aritméticos a los escolares de 6.° y 8.° Los resultados indican que sólo en 8.° los varones son más hábiles que las mujeres resolviendo este tipo de problemas. Se hacen algunas consideraciones adicionales sobre los factores del contexto familiar y escolar que puedan incidir sobre los resultados. 相似文献
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Esteban García-Canal 《Research Policy》2008,37(1):97-114
This paper analyses the influence of technological flows in the choice of joint ventures as a governance form of technology alliances, using a theoretical framework based on Transaction Costs Economics and the Economics of Intellectual Property Rights. We argue that the formation of a joint venture is only necessary in situations for which technological flows make the monitoring of alliance activities and the distribution of cooperation rents difficult. Our hypotheses have been confirmed using a sample of technology alliances created by companies from the European Union between 1992 and 1999. 相似文献
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Do colleges cultivate critical thinking, problem solving, writing and interpersonal skills? 总被引：1，自引：0，他引：1
We investigate how much value college enrollment adds to students’ critical thinking, problem-solving and communication skills, and the role college inputs play in developing these competencies, using data from a 2009 collegiate assessment pilot study in Colombia. Relative to observationally similar first year students, students in their final year of college score about half of a standard deviation higher, with statistically significant higher scores on every individual component of the test. Sensitivity analyses indicate that results are robust to validity threats posed by selection bias. Students in private colleges exhibit significantly higher overall test score differences. Measures of college quality such as selectivity, rankings based on reputation, share of faculty with PhD, share of full-time faculty and expenditures per student, however, are not meaningfully associated with higher test score differences between last and first year students. 相似文献
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Maximal strength and power, muscle mass, endurance and serum hormones in weightlifters and road cyclists 总被引：1，自引：0，他引：1
Izquierdo M Ibáñez J Häkkinen K Kraemer WJ Ruesta M Gorostiaga EM 《Journal of sports sciences》2004,22(5):465-478
Maximal strength, power, muscle cross-sectional area, maximal and submaximal cycling endurance characteristics and serum hormone concentrations of testosterone, free testosterone and cortisol were examined in three groups of men: weightlifters (n = 11), amateur road cyclists (n = 18) and age-matched controls (n = 12). Weightlifters showed 45-55% higher power values than road cyclists and controls, whereas the differences in maximal strength and muscle mass were only 15% and 20%, respectively. These differences were maintained when average power output was expressed relative to body mass or relative to muscle cross-sectional area. Road cyclists recorded 44% higher maximal workloads, whereas submaximal blood lactate concentration was 50-55% lower with increasing workload than in controls and weightlifters. In road cyclists, workloads associated with blood lactate concentrations of 2 and 4 mmol.l-1 were 50-60% higher and occurred at a higher percentage of maximal workload than in weightlifters or controls. Basal serum total testosterone and free testosterone concentrations were lower in elite amateur cyclists than in age-matched weightlifters or untrained individuals. Significant negative correlations were noted between the individual values of maximal workload, workloads at 2 and 4 mmol.l-1 and the individual values of muscle power output (r = -0.37 to -0.49), as well as the individual basal values of serum total testosterone and free testosterone (r = -0.39 to -0.41). These results indicate that the specific status of the participants with respect to training, resistance or endurance is important for the magnitude of the neuromuscular, physiological and performance differences observed between weightlifters and road cyclists. The results suggest that, in cycling, long-term endurance training may interfere more with the development of muscle power than with the development of maximal strength, probably mediated by long-term cycling-related impairment in anabolic hormonal status. 相似文献
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In three experiments, we studied the consequences of ejaculation upon the frustrative or contrast response of male rats exposed
to reward downshift situations (i.e., surprising changes from 32% to 4% sucrose solutions). Similar to what has been found
after treatment with anxiolytic agents, consummatory suppression was partially reversed by previous ejaculations in a second
postshift trial (Experiments 2 and 3), such a result not having been obtained in a first postshift trial (Experiment 1). Moreover,
the effect of ejaculations upon males' behavior during a second postshift trial was transitory, disappearing when assessed
during the third and fourth postshift trials (Experiment 3). These results are in accordance with both Amsel's (1958, 1992)
frustration theory and Flaherty's (1996) multistage hypothesis of successive negative contrast; the diverse factors that are
known to modulate contrast effects are considered, including an interpretation of the present data in terms of the anxiolytic-like
effect of the ejaculation. 相似文献