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91.
Respiratory muscle fatigue has been reported following short bouts of high-intensity exercise, and prolonged, moderate-intensity exercise, as evidenced by decrements in inspiratory and expiratory mouth pressures. However, links to functionally relevant outcomes such as breathing effort have been lacking. The present study examined dyspnoea and leg fatigue during a treadmill marathon in nine experienced runners. Maximal inspiratory and expiratory pressure, peak inspiratory and expiratory flow, forced vital capacity, and forced expiratory volume in one second were assessed before, immediately after, and four and 24 hours after a marathon. During the run, leg effort was rated higher than respiratory effort from 18 through 42 km (P < 0.05). Immediately after the marathon, there were significant decreases in maximal inspiratory pressure and peak inspiratory flow (from 118 +/- 20 cm H(2)O and 6.3 +/- 1.4 litres x s(-1) to 100 +/- 22 cm H(2)O and 4.9 +/- 1.5 litres x s(-1) respectively; P < 0.01), while expiratory function remained unchanged. Leg maximum voluntary contraction force was significantly lower post-marathon. Breathing effort correlated significantly with leg fatigue (r = 0.69), but not inspiratory muscle fatigue. Our results confirm that prolonged moderate-intensity exercise induces inspiratory muscle fatigue. Furthermore, they suggest that the relative intensity of inspiratory muscle work during exercise makes some contribution to leg fatigue.  相似文献   
92.
ABSTRACT

Faculty and students evaluate the curriculum design and delivery of a synchronous online PhD program in social work that prepares scholar-practitioners in social work research, education, and organizational practice. The designers envision a collaborative community of scholars and leaders nurtured by a cohort-based, sequenced curriculum, and intentional faculty mentoring. This teaching and learning platform provides an opportunity to engage with a globally diverse population of doctoral students while fostering both relationships and quality learning outcomes. Educational design and pedagogical features of the program are described and analyzed through the collaborative thinking and learning platform of the Community of Inquiry (CoI) model’s interdependent elements–teaching, cognitive, and social presence. Eighteen students and ten faculty evaluated the strengths and limitations of the online program across each dimension of the model through student course evaluations, focus-group reflections, and qualitative faculty survey data. Student and faculty respondents specified the benefits of synchronous presence across all three dimensions. They also identified significant barriers, particularly in the areas of teaching and social presence. Implications and recommendations are based on a review of findings that inform pedagogical decisions and design options for online PhD education in social work.  相似文献   
93.
94.
In recent years there has been an unprecedented increase in support staff in schools in England and Wales. There were widespread expectations that this will be of benefit to teachers and pupils but there has been little systematic research to address the impact of support staff. This study used a naturalistic longitudinal design to investigate the relationship between the amount of support (measured by teacher estimates and systematic observation) and pupils’ ‘Positive Approaches to Learning’ (PAL) and academic progress. There were over 8000 pupils across two cohorts and seven age groups. Results on PAL were not straightforward by there was a consistent trend for those with most support to make less academic progress than similar pupils with less support, and this was not explained by characteristics of the pupils such as piror attainment or level of special educational need.  相似文献   
95.
Scholars in diverse fields of inquiry have identified the need to expand individual-based information seeking and behavior models and systems to incorporate social as well as collaborative dimensions. However, the research areas of Social Information Seeking (SIS) and Collaborative Information Seeking (CIS) have been largely disconnected from one another despite a few notable attempts to study them under one umbrella. Researchers in these communities have recently realized the value of bringing SIS and CIS together for two main reasons: often it is impossible to separate social and collaborative dimensions in a project; and by considering these two aspects of information seeking, we may be able to support human information behavior in ways not previously possible. A brief synthesis of work in the domains of SIS and CIS is presented here. Then, an integrated view is presented to consider Social and Collaborative Information Seeking (SCIS) as an intersection and extension of SIS and CIS. Benefits of this approach are discussed and the integrated view is used as the basis to present a research agenda that outlines opportunities and challenges unique to SCIS.  相似文献   
96.
The aim of this study was to assess the physical demands of elite English rugby union match-play. Player movements were captured by five distributed video cameras and then reconstructed on a two-dimensional plane representing the pitch. Movements based on speeds were categorized as standing, walking, jogging, and medium-intensity running (low-intensity activity), and high-intensity running, sprinting, and static exertion (scrummaging, rucking, mauling, and tackling) (high-intensity activity). Position groups were defined as forwards (tight and loose) and backs (inside and outside). Backs travelled more total distance than forwards (6127 m, s=724 vs. 5581 m, s=692; P<0.05) and greater distances in walking (2351 m, s=287 vs. 1928 m, s=2342; P<0.001) and high-intensity running (448 m, s=149 vs. 298 m, s=107; P<0.05). Forwards performed more high-intensity activity than backs (9:09 min:s, s=1:39 vs. 3:04 min:s, s=1:01; P<0.001), which was attributable to more time spent in static exertion (7:56 min:s, s=1:56 vs. 1:18 min:s, s=0:30; P<0.001), although backs spent more time in high-intensity running (0:52 min:s, s=0:19 vs. 1:19 min:s, s=0:26; P=0.004). Players travelled a greater distance in the first 10 min compared with 50-60 and 70-80 min, but there was no difference in the amount of high-intensity activity performed during consecutive 10-min periods during match-play. These results show the differing physical demands between forwards and backs with no evident deterioration in high-intensity activity performed during match-play.  相似文献   
97.
The sweet spot of a cricket bat for low speed impacts   总被引:1,自引:1,他引:1  
The impact location of a cricket ball on a cricket bat has a large influence on the resulting rebound velocity of the ball. To measure this, a cricket bat was swung in a pendulum motion towards a cricket ball suspended in space. The position of the ball was modified so that it impacted the bat at 24 different positions on the face of the bat. This included six positions longitudinally and four positions laterally. The speed of the bat and each rebound were measured by a radar gun so that the apparent coefficient of restitution (ACOR) could be calculated. Impacts occurring centrally and 1?cm either side of the midline produced significantly higher rebound speeds and ACOR??s than impacts occurring 2 and 3cm off centre (p?<?0.01). Impacts occurring 15?C20?cm from the base of the bat produced the highest rebound speeds (p?<?0.01) and impacts occurring 20?C30?cm from the base of the bat produced the highest ACOR values. Implications for higher speed impacts and game scenarios are discussed.  相似文献   
98.
Elite tennis is characterised by repeated bouts of up to 5-set match play, yet little is known about the technical requirements of shots played. This study therefore investigated technical performance changes over consecutive days of prolonged, simulated tennis match play. A total of 7 well-trained men tennis players performed 4 consecutive days of competitive 4-h match play. Matches were notated to determine between-day changes in groundstroke and serve performance, as well as point and match durations. Changes ≥75% likely to exceed the smallest important effect size (0.2) were considered meaningful and represented as effect size ± 90% confidence interval. Effective playing time reduced on days 3 and 4, alongside likely increases in “stretch” groundstrokes over the 4 days (mean effect size ± 90% confidence interval; 0.57 ± 0.38) and “stretch” backhand returns on days 2 and 3 (0.39 ± 0.54 and 0.67 ± 0.55). Relative unforced errors increased on day 4 (vs. day 2; 0.36 ± 0.22) and second-serve winning percentage reduced after day 1 (?0.47 ± 0.50). Further, a likely increase in emotional outbursts characterised day 3 (vs. day 2; 0.73 ± 0.57). Consecutive-day match play impairs hitting accuracy, stroke positioning and emotional responses; an understanding of which prepares players for elite-standard tennis tournament play.  相似文献   
99.
100.
This paper introduces an experimental model to measure the holistic performance of professional football clubs. The model utilizes a selection of established financial and sporting indicators, which are weighted in accordance with their perceived relative importance and in relation to components of financial management and governing body regulations. The paper uses data pertaining to clubs competing in the English Premier League to demonstrate the outputs of the model. The authors argue that although the model is experimental, it still provides a useful platform to analyse performance of football clubs through further scientific investigation.  相似文献   
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