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31.
Cemal Ozemek Mitchell H. Whaley W. Holmes Finch Leonard A. Kaminsky 《European Journal of Sport Science》2017,17(5):563-570
There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HRmax) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HRmax with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HRmax for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R2 (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HRmax explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HRmax. 相似文献
32.
Hugh C. Mitchell 《Journal of The Franklin Institute》1925,200(4):558-559
33.
Mitchell E. Kusy 《Performance Improvement Quarterly》1988,1(2):23-30
With organizations becoming leaner during times of cost consciousness, it is becoming critical that training departments demonstrate their contributions to their bottom lines by becoming more productivity based than they have been historically. For training professionals to obtain the needed financial and organizational support of their training efforts, top management should corroborate the training function. To gain this support, training professionals have evaluation procedures available to them. My purpose for conducting this study was to determine which type of training evaluation method (reaction, learning, behavior, or results) elicited the most management support of the training function among corporate managers. I designed and distributed a case study survey instrument (TEMS) to assess the extent of this support. MBA students with management experience and non-training managers participated in the study. For both samples, the data indicated that the results evaluation format received the most support, with progressively less support for behavior, learning, and reaction evaluations, respectively. I believe that this study provides training practitioners with a mandate for demonstrating training results to top management. It further gives an accountability system for gaining management support of the training function. 相似文献
34.
Keith?KoenigEmail author Nan?Davis?Mitchell Thomas?E.?Hannigan J.?Keith?Clutter 《Sports Engineering》2004,7(2):105-117
The speed at which a player can swing a bat is central to the games of baseball and softball, determining, to a large extent,
the hit speed of the ball. Experimental and analytical studies of bat swing speed were conducted with particular emphasis
on the influence of bat moment of inertia on swing speed. Two distinct sets of experiments measured the swing speed of colege
baseball and fast-pitch softball players using weighted rods and modified bats. The swing targets included flexible targets,
balls on a tee and machine pitched balls. Internal mass alterations provided a range of inertial properties. The average measured
speeds, from 22 to 31 m s−1, are consistent with previous studies. Bat speed approximately correlates with the moment of inertia of the bat about a vertical
axis of rotation through the batter's body, the speed generally decreasing as this moment of inertia increases. The analytical
model assumes pure rotation of the batter/bat system about a vertical axis through the batter's body. Aerodynamic drag of
the batter's arms and the bat is included in the model. The independent variable is bat moment of inertia about the rotation
axis. There is reasonable agreement between the model and the measured speeds. Detailed differences between the two suggest
the importance of additional degrees of freedom in determining swing speed. 相似文献
35.
ABSTRACT This article highlights key events in the relationship between OCLC Online Computer Library Center, Inc. and the Dewey Decimal Classification (DDC) system. The formal relationship started with OCLC's acquisition of Forest Press and the rights to the DDC from the Lake Placid Education Foundation in 1988, but OCLC's research interests in the DDC predated that acquisition and have remained strong during the relationship. Under OCLC's leadership, the DDC's value proposition has been enhanced by the continuous updating of the system itself, development of interoperable translations, mappings to other schemes, and new forms of representation of the underlying data. The amount of categorized content associated with the system in WorldCat and elsewhere has grown, as has worldwide use of the system. Emerging technologies are creating new opportunities for publishing, linking, and sharing DDC data. 相似文献
36.
Heidi R. Thornton Joanna Miller Lee Taylor Charli Sargent Michele Lastella 《Journal of sports sciences》2018,36(13):1476-1484
Currently, very little is known about the impact of short- or long-haul air travel on the sleep and wellbeing of wheelchair basketball athletes. Eleven national wheelchair basketball athletes wore actigraphy monitors prior, during, and after air travel to the United Kingdom. Upon arrival, participants rated their subjective jet-lag, fatigue, and vigor. Individuals traveled to the United Kingdom from different locations in Australia, the United States, and Europe and were categorised according to travel length [LONG (up to 30.2 h) or SHORT (up to 6.5 h)]. Linear mixed models determined effects of travel length on sleep and subjective ratings of jet-lag, fatigue, and vigor. During competition, subjective fatigue and jet-lag were substantially higher (ES = 0.73; ±0.77) and (ES = 0.57; ±0.60), subjective vigor was lower (ES = 1.94; ±0.72), and get-up time was earlier (ES = 0.57; ±0.60) for LONG when compared to SHORT. Travelling greater distances by airplane had a larger effect on subjective ratings of jet-lag, fatigue and vigor, rather than sleep. Irrespective of travel group, sleep and subjective responses were compromised, reflecting the travel requirements, competition-mediated influences, and/or due to a change in environment. 相似文献
37.
Catherine B. Woods Kevin Volf Liam Kelly Blthín Casey Peter Gelius Sven Messing Sarah Forberger Jeroen Lakerveld Joanna Zukowska Enrique García Bengoechea PEN consortium 《运动与健康科学(英文)》2021,10(3):263-276
BackgroundDespite the well-established health benefits of physical activity (PA) for young people (aged 4–19 years), most do not meet PA guidelines. Policies that support PA in schools may be promising, but their impact on PA behavior is poorly understood. The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.MethodsThis systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Six databases were searched using key concepts of policy, school, evaluation, and PA. Following title and abstract screening of 2323 studies, 25 progressed to data synthesis. Methodological quality was assessed using standardized tools, and the strength of the evidence of policy impact was described based on pre-determined codes: positive, negative, inconclusive, or untested statistically.ResultsEvidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting. These were whole school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks/recess, physical environment, shared use agreements, active school transport, and surveillance. The bulk of the evidence was significantly positive (54%), 27% was inconclusive, 9% was significantly negative, and 11% was untested (due to rounding, some numbers add to 99% or 101%). Frequency of evidence was highest in the primary setting (41%), 34% in the secondary setting, and 24% in primary/secondary combined school settings. By policy area, frequency of evidence was highest for sport/extracurricular PA (35%), 17% for physical education, and 12% for whole school PA policy, with evidence for shared use agreements between schools and local communities rarely reported (2%). Comparing relative strength of evidence, the evidence for shared use agreements, though sparse, was 100% positive, while 60% of the evidence for whole school PA policy, 59% of the evidence for sport/extracurricular PA, 57% of the evidence for physical education, 50% of the evidence for PA in classroom, and 50% of the evidence for active breaks/recess were positive.ConclusionThe current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a “one-size-fits-all” approach and emphasizes the need to examine policy implementation to maximize translation into practice. Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed. 相似文献
38.
Whilst the measurement and quantification of vertical leg stiffness (Kvert) asymmetry is of important practical relevance to athletic performance, literature investigating bilateral asymmetry in Kvert is limited. Moreover, how the type of task used to assess Kvert may affect the expression of asymmetry has not been properly determined. Twelve healthy males performed three types of performance tasks on a dual force plate system to determine Kvert asymmetries; the tasks were (a) bilateral hopping, (b) bilateral drop jumping and (c) unilateral drop jumping. Across all the three methods, Kvert was significantly different between compliant and stiff limbs (P < 0.001) with a significant interaction effect between limb and method (P = 0.005). Differences in Kvert between compliant and stiff limbs were ?5.3% (P < 0.001), ?21.8% (P = 0.007) and ?15.1% (P < 0.001) for the bilateral hopping, bilateral drop jumping and unilateral drop jumping methods, respectively. All the three methods were able to detect significant differences between compliant and stiff limbs, and could be used as a diagnostic tool to assess Kvert asymmetry. Drop jumping tasks detected larger Kvert asymmetries than hopping, suggesting that asymmetries may be expressed to a greater extent in acyclic, maximal performance tasks. 相似文献
39.
Kyung-Sun Kim Sei-Ching Joanna Sin EunYoung Yoo-Lee 《Library & information science research》2021,43(3):101104
This cohort study examined longitudinal changes in undergraduates' use of social media as information sources in academic and everyday-life contexts, covering types of social media used, purposes of use, and evaluation strategies. Web surveys were used, collecting data from 1,355 and 928 undergraduates in 2013 and 2019. The study found that students used most types of social media less in 2019 than 2013 in both contexts. Only media-sharing services bucked this downward pattern. Overall, a majority of social media types underwent changes in the top three purposes of use. The 2019 cohort used most evaluation strategies more frequently in both contexts. However, they favored simplistic strategies relying on superficial physical cues when evaluating information. Based on the findings, this study provided recommendations for information literacy education and interface design, such as covering multimedia information evaluation, leveraging various heuristics to prime careful use of social media and analytical evaluation of information. 相似文献
40.
Nullis in verba was chosen as the motto of the Royal Society, as it embodied the culture of transparency and collaboration that were the hallmarks of the Royal Society and of the scientific method it promoted. Communication, using the tools of the day, was essential to this community of scientists as they created and shared new knowledge. Almost three hundred years later, libraries continue to advance principles relating to the importance of collaboration and transparency. This two-part article series, published jointly in International Information and Library Review and Technical Services Quarterly explores notions of transparency and collaboration in research and how these ideas are impacting the world of librarianship – from information creation, organization and access perspectives. 相似文献