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41.
Lees A Owens L 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(2):125-134
The purpose of this paper was to establish postural cues in kicking that may be of use to goalkeepers. Eight male soccer players (age 20.5 +/- 1.1 yrs; height 1.78 +/- 0.053 m; mass 75.18 +/- 9.66 kg) performed three types of kick: a low side-foot kick to the left hand corner of the goal, a low side-foot kick straight ahead, and a low instep kick straight ahead. Kicks were recorded by an optoelectronic motion analysis system at 240 Hz. At kicking foot take-off (about 200 ms before ball contact) the variables which were significantly different and could act as cues were support foot progression angle, pelvis rotation, and kicking hip and ankle flexion. The support foot progression angle was considered to be the most valuable of these variables as its angle coincided with the direction of ball projection. The other variables were less clear in their interpretation and so less valuable for a goalkeeper to use for decision making. Cues appearing after support foot contact were thought unlikely to be of value to a goalkeeper in their decision making. These include kicking leg knee flexion angle, and support leg shank and thigh angles. 相似文献
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Liam BORGSTROM 《Learned Publishing》2013,26(2):115-122
While XML‐based single‐source publishing is a powerful tool for streamlining the book publishing industry, it may not be the right one for every sector of the industry. For an industry that is part cultural and part industrial, the traditional workflow allows for creativity at every stage and this craft focus still deserves a place in defining how the industry functions. With simple and familiar tools, it can be possible to integrate elements of old and new principles to create a workflow that is streamlined and advantageous without being too radical a shift in practice. This article describes the factors that are important to creating publications in both digital and physical formats. 相似文献
43.
Liam Kilduff Christian J. Cook Mark Bennett Blair Crewther Richard Michael Bracken John Manning 《Journal of sports sciences》2013,31(6):677-683
Abstract There is evidence that the digit ratio (2D:4D) is a negative correlate of prenatal levels of testosterone, but there is no association between 2D:4D and the circulating levels of both total and free testosterone. Sports provide a physical challenge and participants often show increased levels of free testosterone immediately preceding and during competition. We tested this hypothesis of a link between 2D:4D and testosterone under challenge in 79 professional rugby players using the following procedures; (i) 25 players were physically challenged using a repeated sprint agility test, and saliva samples were assayed for testosterone immediately preceding the repeated sprint agility test (time 1) and 5 minutes (time 2) and 20 minutes after completion of the repeated sprint ability (time 3); (ii) 54 players were also tested for salivary testosterone in an unchallenged condition. We found that right-left 2D:4D was significantly and negatively related to testosterone concentrations at times 1, 2 and 3 following the repeated sprint agility test (P < 0.05) and there was no association between the 2D:4D and basal testosterone levels in the unchallenged group. We suggest that low right–left 2D:4D is a predictive marker of free testosterone responsiveness when trained men are physically challenged, and that this association is programmed by the action of prenatal testosterone. 相似文献
44.
Liam Anderson Patrick Orme Rocco Di Michele Graeme L Close Ryland Morgans Barry Drust 《Journal of sports sciences》2016,34(13):1250-1259
Muscle glycogen is the predominant energy source for soccer match play, though its importance for soccer training (where lower loads are observed) is not well known. In an attempt to better inform carbohydrate (CHO) guidelines, we quantified training load in English Premier League soccer players (n = 12) during a one-, two- and three-game week schedule (weekly training frequency was four, four and two, respectively). In a one-game week, training load was progressively reduced (P < 0.05) in 3 days prior to match day (total distance = 5223 ± 406, 3097 ± 149 and 2912 ± 192 m for day 1, 2 and 3, respectively). Whilst daily training load and periodisation was similar in the one- and two-game weeks, total accumulative distance (inclusive of both match and training load) was higher in a two-game week (32.5 ± 4.1 km) versus one-game week (25.9 ± 2 km). In contrast, daily training total distance was lower in the three-game week (2422 ± 251 m) versus the one- and two-game weeks, though accumulative weekly distance was highest in this week (35.5 ± 2.4 km) and more time (P < 0.05) was spent in speed zones >14.4 km · h?1 (14%, 18% and 23% in the one-, two- and three-game weeks, respectively). Considering that high CHO availability improves physical match performance but high CHO availability attenuates molecular pathways regulating training adaptation (especially considering the low daily customary loads reported here, e.g., 3–5 km per day), we suggest daily CHO intake should be periodised according to weekly training and match schedules. 相似文献
45.
Liam Smith 《Curator: The Museum Journal》2009,52(1):101-115
Abstract Although many zoos and zoo associations state the capability and importance of influencing the behavior of zoo visitors, the little research conducted to date gives limited support for these statements. Addressing this deficit involves more research, but zoos also need to design communication strategies with the specific purpose of influencing visitor behavior. However, it's important, before designing a communication campaign, that zoos identify which behaviors to target. As a first step toward doing this, five nominal group technique (NGT) sessions were conducted with general staff from three zoos in Australia, as well as an executive body overseeing three zoos and members of a volunteer group for an urban zoo. Following NGT protocol, desired on‐site and off‐site visitor behaviors were identified and their importance prioritized. The most prioritized behaviors are presented here. The discussion in this paper focuses on the efficacy of the NGT sessions, the need for further capacity‐building in Australian zoos, and proposals for some areas of future research. 相似文献
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Anthony White Samuel P. Hills Matthew Hobbs Carlton B. Cooke Liam P. Kilduff Christian Cook 《Journal of sports sciences》2020,38(8):848-854
ABSTRACTThe physical demands of English Premier League soccer goalkeepers were quantified during training and match-play in a two-part study. Goalkeeper-specific micromechanical electrical systems (MEMS) devices, profiled training and match-day activities throughout one competitive week (n=8; part A). Changes in MEMS-derived outputs were also profiled throughout match-play (100 matches; n=8, 18±14 observations per goalkeeper; part B). In part A, goalkeeping-training elicited the most dives (51±11) versus all activities (all p≤0.030) except shooting-training (p=0.069). Small-sided games elicited the fewest (5±3) dives (all p≤0.012). High-speed distance covered in match (103±72 m) was similar to goalkeeping-training (p=0.484), while exceeding shooting-training, small-sided games, pre-match shooting, and pre-match warm-up (all p=0.012). Most changes of direction (34±12) and explosive efforts (70±18) occurred during goalkeeping-training, with values exceeding match (both p=0.012). In part B, between-half reductions in total distance, but increased high-speed changes of direction and explosive efforts, occurred (both p≤0.05). Excluding the number of high jumps, all variables differed from 0-15-min during at least one match epoch, with more dives (1.3±1.4 vs 1.0±1.1) and explosive efforts (2.5±2.4 vs 2.0±1.8) performed between 75-90-min versus 0-15-min (all p<0.05). These data highlight the differing physical demands of various activities performed by professional soccer goalkeepers throughout a competitive week. 相似文献
48.
Kilduff LP Owen N Bevan H Bennett M Kingsley MI Cunningham D 《Journal of sports sciences》2008,26(8):795-802
Following a bout of heavy resistance training, the muscle is in both a fatigued and potentiated state with subsequent muscle performance depending on the balance between these two factors. To date, there is no uniform agreement about the optimal acute recovery required between the heavy resistance training and subsequent muscle performance to gain performance benefits. The aim of the present study was to determine the recovery time required to observe enhanced muscle performance following a bout of heavy resistance training. Twenty professional rugby players performed a countermovement jump at baseline and approximately 15 s, 4, 8, 12, 16, 20, and 24 min after a bout of heavy resistance training (three sets of three repetitions at 87% one-repetition maximum squat). Power output, jump height, and peak rate of force development were determined for all countermovement jumps. Despite an initial decrease in countermovement jump performance after the heavy resistance training (P<0.001), participants' performance increased significantly following 8 min recovery (P<0.001) (i.e. jump height increased by 4.9%, s=3.0). The findings suggest that muscle performance during a countermovement jump can be markedly enhanced following bouts of heavy resistance training provided that adequate recovery (approximately 8 min) is allowed between the heavy resistance training and the explosive activity. 相似文献
49.
Joseph Henson Charlotte L. Edwardson Melanie J. Davies Jason M.R. Gill Liam M. Heaney Kamlesh Khunti 《Journal of sports sciences》2020,38(10):1150-1160
ABSTRACT The aim was to investigate how measurements of the lipidome differ according to the level and intensity of physical activity in a population at high risk of type 2 diabetes (T2DM). A targeted metabolomics platform provided quantitative molecular data on lipid species. Linear regression examined the associations between plasma lipid concentrations, particle size and time spent in objectively measured physical activity intensity domains, in increments of 500 counts per minute (cpm) (up to >4500 cpm (~>5.6METs)). Results are presented as % difference in the concentration (lower/higher) or particle size (smaller/larger) per 10 min of activity within each intensity. Five hundred and nine participants were included. Time spent in the lowest physical activity intensity domain (<500 cpm) was unfavourably associated with VLDL (2%), HDL (?2%) and Apolipoprotein A-1 particle concentrations (?2%) and HDL diameter (?2%). Conversely, time spent in intensities ≥1000 cpm were favourably associated with HDL subclass concentrations; with stronger associations seen at moderate intensities (2000-3999 cpm (~4.5METs)). For Apolipoprotein-B concentration and VLDL particle concentration and size, a negative association was consistently observed at the highest physical activity intensity only. If these associations are causal, HDL subclasses appear sensitive to light-intensities whereas only the high category of physical activity intensity was consistently associated with VLDL subclasses. 相似文献
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