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921.
Lachlan Mitchell Gary Slater Daniel Hackett Nathan Johnson Helen O’connor 《European Journal of Sport Science》2018,18(5):619-629
This study aimed to describe the body composition and physiological changes which take place during the in-season and recovery periods of a group of natural bodybuilders. Natural male bodybuilders (n?=?9) were assessed 16 (PRE16), 8 (PRE8), and 1 (PRE1) week(s) before, and 4 (POST4) weeks after a bodybuilding competition. Assessments included body composition, resting metabolic rate (RMR), serum hormones, and 7-day weighed food and training diaries. Change in parameters was assessed using repeated-measures analysis of variance. Dietary protein intake remained high throughout the study period (2.8–3.1?g?kg?1?d?1). Fat mass (FM) was significantly reduced from PRE16 to PRE1 (8.8?±?3.1 vs. 5.3?±?2.4?kg, P?.01). There was a small decrease in lean mass (LM) from PRE8 to PRE1 (71.8?±?9.1 vs. 70.9?±?9.1?kg, P?.05). No changes in RMR were observed (P?>?.05). Large reductions in total and free testosterone (16.4?±?4.4 vs. 10.1?±?3.6?nmol?L?1, P?.05; 229.3?±?72.4 vs. 116.8?±?76.9?pmol?L?1, P?.05), and insulin-like growth factor-1 (IGF-1) (27.0?±?7.7 vs. 19.9?±?7.6?nmol?L?1, P?.05) occurred between PRE16 and PRE1. LM and IGF-1 increased from PRE1 to POST4 (70.9?±?9.1 vs. 72.5?±?8.5?kg, P?.05; 19.9?±?7.6 vs. 25.4?±?9.3?nmol?L?1, P?.05). Despite substantial reductions in FM, participants maintained almost all of their LM. The reduction in anabolic hormone concentration is likely attributable to the prolonged negative energy balance, despite a high dietary protein intake. 相似文献
922.
Tiago M. Barbosa Rui Ramos António J. Silva Daniel A. Marinho 《Journal of sports sciences》2018,36(5):492-498
The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (Df), pressure drag (Dpr), total passive drag force (Df+pr) and drag coefficient (CD) were computed between 1.3 and 2.5 m · s?1 by both techniques. Df+pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). CD ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40–6.30%). Linear regression models showed a very high association for Df+pr plotted in absolute values (R2 = 0.98) and after log–log transformation (R2 = 0.99). The CD also obtained a very high adjustment for both absolute (R2 = 0.97) and log–log plots (R2 = 0.97). The bias for the Df+pr was 8.37 N and 0.076 N after logarithmic transformation. Df represented between 15.97% and 18.82% of the Df+pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one’s hydrodynamics characteristics. 相似文献
923.
Daniel Mayorga-Vega Alejandro Martínez-Baena Jesús Viciana 《Journal of sports sciences》2018,36(17):1913-1922
Physical education has been highlighted as an important environment for physical activity promotion, however, to our knowledge there are no previous studies examining the contribution of physical education to daily accelerometer-measured physical activity and non sedentary behaviour. The purpose was to compare the accelerometer-measured physical activity and sedentary behaviour between physical education, non-physical education and weekend days in adolescents. Of the 394 students from a Spanish high school that were invited to participate, 158 students (83 boys and 75 girls) aged 13–16 years were analyzed (wear time ≥ 600 min). Participants’ physical activity and sedentary behaviour were objectively-measured by GT3X+ accelerometers during physical education (one session), non-physical education and weekend days. Results indicated that overall adolescents had statistically significant greater physical activity levels and lower values of sedentary behaviour on physical education days than on non-physical education and weekend days (e.g., moderate-to-vigorous physical activity = 71, 54 and 57 min; sedentary = 710, 740 and 723 min) (p < 0.05). Physical education contributes significantly to reducing students’ daily physical inactivity and sedentary behaviour. Increasing the number of physical education classes seems to be an effective strategy to reduce the high current prevalence of physical inactivity and sedentary behaviour in adolescence. 相似文献
924.
Christiane Lösch Nico Nitzsche Christian Maiwald Daniel Zschäbitz Martin Weigert Henry Schulz 《Sportwissenschaft》2018,48(3):428-437
In the context of strength training in rehabilitation, visual movement control can be helpful to ensure correct movements. However, there are only a few studies that deal with the effectiveness of feedback during resistance exercises. To investigate the effect of feedback during guided exercise, 18 young adults (28.8?±?5.5 years) and 12 senior citizens (67.9?±?4.1 years) were tested. Subjects performed shoulder press exercises (3 sets, 15 repetitions) with and without visual movement control in a randomized order. On day 1, the subjects trained without load, and on day 2 they trained at 50% of their single repetition maximum. Joint articulation at the elbow was recorded using elbow extension and flexion. Autocorrelation was used to determine the reproducibility of movements. Subjects achieved better reproducibility of the movement with feedback than without (χ2?=?19.73; p?<?0.001). There was no effect of the load on motion accuracy (p?>?0.05), but the age group showed a significant effect (χ2?=?6.00; p?=?0.014). The younger group shows a higher degree of movement accuracy. In summary, visual movement control is useful in guided exercises to control movement execution. In clinical setting, this may be a way to control the motion performance of guided strength exercises and to ensure purposeful muscle work. Further studies should clarify the effect of visual feedback on the movement quality in unguided strength exercises. 相似文献
925.
Daniel J. Wilson 《Performance Improvement》2009,48(9):38-43
When independent human performance technology (HPT) consultants need practical guidance managing their own firms, they are thrust into a complex, confusing, and uncompassionate network of guides. This article focuses on the practical side of managing an independent HPT consulting practice. Several aspects are considered, including physical setting, legal structure, financial concerns, sales and marketing, pricing, and affiliations or alliances. In addition to a review of relevant literature, a survey of 150 independent consultants was reviewed and several interviews of independent consultants were conducted. 相似文献
926.
Daniel Kassahun Waktola 《Environmental Education Research》2009,15(5):589-605
Lack of environmental awareness is one of the underlying causes of severe environmental degradation in Ethiopia. As teachers' colleges are a seedbed of such awareness, assessment of college curricula should shed light on the possibilities they offer to develop capacities to address environmental degradation. This small‐scale study is based on the assessment of the curricula of the Kotebe and St Mary's teachers' colleges, Ethiopia, and the knowledge and opinions of a sample of teaching students on pertinent environmental issues facing the country. Comparative analysis of data generated through questionnaires and interviews was undertaken across college, curricula and gender categories. The results suggest: a ‘paradigm shift’ from a core‐focused to a pedagogical‐focused curriculum in the last three decades; a declining trend in the provision of outdoor environmental education; inadequate levels of factual knowledge amongst current college students; and variations in knowledge levels and attitudes among the respondents taking different curricula. If the work of teachers' colleges is to support wider efforts throughout Ethiopia to address the causes and effects of environmental degradation, the findings of the study underscore the necessity of revisiting the composition of course categories and maintaining the existence of outdoor environmental education in the current college curricula. 相似文献
927.
Leslie Hill Daniel Maier-Katkin Roshni Ladny Kirsten Kinsley 《Journal of Criminal Justice Education》2018,29(1):116-136
The paper is an extension of a previous study, which examined student perceptions of a unique freshman seminar offered to Criminology and Criminal Justice students at Florida State University. The seminar is characterized by a heavy focus on interactive library sessions in which students learn how to conduct research and write a scholarly paper. The previous article reported on student perceptions of research and writing skills developed in the seminar. This report, using Multivariate Regression and Propensity Score Matching reveals that compared to a carefully constructed comparison group, first time in college students enrolled in the seminar have statistically significantly higher cumulative grade point averages and percentages of graduation within four years. The seminar’s emphasis on the library as a research tool is thought to have contributed to the differences seen on academic outcomes between students who took the seminar and a matched comparison group. 相似文献
928.
Patrick J. Curran Veronica T. Cole Daniel J. Bauer W. Andrew Rothenberg Andrea M. Hussong 《Structural equation modeling》2018,25(6):860-875
Although it is currently best practice to directly model latent factors whenever feasible, there remain many situations in which this approach is not tractable. Recent advances in covariate-informed factor score estimation can be used to provide manifest scores that are used in second-stage analysis, but these are currently understudied. Here we extend our prior work on factor score recovery to examine the use of factor score estimates as predictors both in the presence and absence of the same covariates that were used in score estimation. Results show that whereas the relation between the factor score estimates and the criterion are typically well recovered, substantial bias and increased variability is evident in the covariate effects themselves. Importantly, using covariate-informed factor score estimates substantially, and often wholly, mitigates these biases. We conclude with implications for future research and recommendations for the use of factor score estimates in practice. 相似文献
929.
Daniel C. Levy 《Higher Education》2018,76(4):701-715
Societies’ relative use of private and public services is an abiding and significant issue of scholarly and policy interest. For higher education, however, there has hitherto been no comprehensive dataset and, accordingly, no extensive, reliable analysis of the private-public distribution. As this article provides both the dataset and the analysis, it allows us to discover both the size and geographical shape of global private higher education. Having grown greatly for decades, the private sector now holds a third (32.9%) of the world’s total higher education enrollment. We find striking patterns of concentration and dispersion. The several largest country systems account for much of the private enrollment but, simultaneously, private sectors now exist in all but a few systems; a stunning 97.6% of the world’s present enrollment is in systems with dual-sector provision. Societies no longer rely exclusively on public provision. We discover too that private enrollment concentrates mostly in developing regions, though it is noteworthy in developed regions as well. Asia and Latin America are the twin giants but in all regions, at least 10% of students are in the private sector. 相似文献
930.