186 research outputs found

    Motion analysis of elite Polish soccer goalkeepers throughout a season

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    The study aims were to determine the distance covered by goalkeepers during matches in the context of game duration and result, to identify the area of their most frequent activity, and to assess goalkeepers' involvement in games finished with a win, draw, or loss. The investigation was based on two innovative tools: the goalkeeper's activity index (GAI) and an analysis of 5-min periods. A video tracking system was used to monitor 17 goalkeepers from Polish National League teams during 15 matches. The GAI was applied to assess their involvement in the game. Elite goalkeepers covered 72.7%, 25.8%, and 2.5% of the distance during the game by walking/jogging, running, and sprinting, respectively. The distances covered in lost, won, and drawn matches turned out similar (mean \ub1 SD: 4800 \ub1 906 m, 4696 \ub1 1033 m, and 4660 \ub1 754 m, respectively). There were no significant differences between the distances covered in the first and second halves. The area of most frequent activity was the middle sector of the penalty area between the goal and penalty area lines. ANOVA results showed that in drawn matches, goalkeepers' activity significantly differed in mean values of the GAI in comparison with that in won and lost games (p = 0.034, p = 0.039, respectively). It was noted that goalkeepers tended to intervene more often in games where their team was winning rather than in those with a losing result. Their direct involvement in defending the goal was the lowest in drawn games

    Anthropometric and physical characteristics allow differentiation of young female volleyball players according to playing position and level of expertise

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    The aim of our study was to determine the differences in some anthropometric and physical performance variables of young Croatian female volleyball players (aged 13 to 15) in relation to playing position (i.e., independent variable) and performance level within each position (i.e., independent variable). Players were categorized according to playing position (i.e., role) as middle blockers (n=28), opposite hitters (n=41), passer-hitters (n=54), setters (n=30), and liberos (n=28). Within each position, players were divided into a more successful group and a less successful group according to team ranking in the latest regional championship and player quality within the team. Height and body mass, somatotype by the Heath-Carter method, and four tests of lower body power, speed, agility and upper body power (i.e., dependent variables) were assessed. Players in different positions differed significantly in height and all three somatotype components, but no significant differences were found in body mass, body mass index or measured physical performance variables. Players of different performance level differed significantly in both anthropometric and physical performance variables. Generally, middle blockers were taller, more ectomorphic, less mesomorphic and endomorphic, whereas liberos were shorter, less ectomorphic, more mesomorphic and endomorphic than players in other positions. More successful players in all positions had a lower body mass index, were less mesomorphic and endomorphic, and more ectomorphic than less successful players. Furthermore, more successful players showed better lower body power, speed, agility and upper body power. The results of this study can potentially provide coaches with useful indications about the use of somatotype selection and physical performance assessment for talent identification and development

    Validity and reliability of a light-based electronic target for testing response time in fencers

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    Response time is a fencing fundamental sensorimotor skill. Therefore, the aim of the current study was to examine the efficacy of a light-based electronic target in fencers, designed to measure and train this entity. Ninety-five fencers (M=53; F=42) were tested in regard to their response time, using a light-based electronic target, for three different attack types: simple attack, the lunge, and an attack following a 1.5-m thrust. All participants were divided into elite vs. novice fencers. Elite fencers had national and international rankings, and were again divided with regard to used weapon: épéeists (n=32; M=19; F=13) and foilists (n=30; M=13; F=17). Measurement was evaluated for validity/reliability, sensitivity/specificity, and correlation. Reliability was high for all attack types (ICC 0.94-0.96). Lower response times were found in males for two attack types with good sensitivity (81-93%)/specificity (50-91%) for all attack types. Elite fencers responded faster than novice fencers for all attack types (P<0.001), whereas elite males were faster than females for two attack types (P<0.01). Lower response times in females correlated with level for one attack type (r=0.797, P<0.05). In conclusion, the light-based electronic target system was found to be highly reliable and therefore could be used by fencing athletes as a further measure of performance

    Track running shoes: a case report of the transition from classical spikes to "super spikes" in track running

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    Research on high-tech running shoes is increasing but few studies are available about the use of high-tech track spike shoes (super spikes), despite their growing popularity among running athletes. The aim of this case study was to investigate kinematics, kinetics, and plantar pressures of an Olympic running athlete using two different types of shoes, to provide an easy and replicable method to assess their influence on running biomechanics. The tested athlete performed six running trials, at the same speed, wearing a pair of normal spikes shoes (NSS) and a super spikes shoe (SSS), in random order. SSS increased contact time, vertical impact, and swing force (Effect Size 3.70, 7.86, and 1.31, respectively), while it reduced foot-strike type and vertical ground reaction force rate (Effect Size 3.62 and 7.21, respectively). Moreover, a significant change was observed in medial and lateral load, with SSS inducing a more symmetrical load distribution between the left and right feet compared to the NSS (SSS left medial load 57.1 +/- 2.1%, left lateral load 42.9 +/- 1.4%, right medial load 55.1 +/- 2.6%, right lateral load 44.9 +/- 2.6%; NSS left medial load 58.4 +/- 2.6%, left lateral load 41.6 +/- 2.1%, right medial load 49.2 +/- 3.7%, right lateral load 50.8 +/- 3.7%). The results of this case study suggest the importance of using individual evaluation methods to assess shoe adaptations in running athletes, which can induce biomechanical modifications and should be considered by coaches to ensure optimal running performance

    Effects of Gradient and Speed on Uphill Running Gait Variability

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    Background: The aim of this study was to investigate the effects of gradient and speed on running variability (RV) and local dynamic stability (LDS) during uphill running. Hypotheses: (1) Both gradient and speed increase metabolic effort, in terms of heart rate (HR) and perceived exertion (CR10), in line with the contemporary literature, and (2) gradient increases RV and impairs LDS. Study design: “Crossover” observational design. Level of Evidence: Level 3. Methods: A total of 25 runners completed 10-minute running trials in 3 different conditions and in a randomized order: gradient at 0% (0CON), 2% (2CON), and 2% at isoefficiency speed (2IES). 0CON and 2CON speeds were calculated as the “best 10-km race performance” minus 1 km·h−1, whereas 2IES speed was adjusted to induce the same metabolic expenditure as 0CON. HR and perceived exertion as well as running kinematic variables were collected across all trials and conditions. Running variability was calculated as the standard deviation of the mean stride-to-stride intervals over 100 strides, while LDS was expressed by the Lyapunov exponent (LyE) determined on running cycle time over different running conditions. Results: Increases in HR and CR10 were observed between 0CON and 2CON (P &lt; 0.001) and between 2IES and 2CON (P &lt; 0.01). Higher RV was found in 2CON compared with 0CON and 2IES (both P &lt; 0.001). Finally, the largest LyE was observed in 2IES compared with 0CON and 2CON (P = 0.02 and P = 0.01, respectively). Conclusion: Whereas RV seems to be dependent more on metabolic effort, LDS is affected by gradient to a greater extent. Clinical Relevance: Running variability could be used to monitor external training load in marathon runners

    Report of the Workshop on Policy-Driven Analysis of Food Consumption and Access Data to improve Micronutrient Intakes

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    There are currently several global research and evidence generation projects working to inform micronutrient programming, particularly fortification, using household- or individual-level dietary data and modelling techniques. While these projects collaborate and keep each other updated, there had been limited opportunity to work together in-person and explore opportunities for aligning analytical approaches and evidence outputs intended. As well as identifying complementary research that, together, provide a stronger, more comprehensive evidence base. There was also an interest in ensuring policy relevance and applicability of these analyses and evidence generation and seeking guidance on how to improve this as a group. The five-day workshop on policy-driven analysis of food consumption, micronutrient status and access data to improve micronutrient intakes was a collaborative effort to bring together global nutrition modelling and data projects (including MIMI, MAPS, MINIMOD, Fraym, DInA, and the FAOSTAT Food & Diet Domain and FAO/WHO GIFT Platform) with national policymakers, to better understand the functions and outputs of each project, combine analysis and outputs and explore how this work could be more policy responsive. The workshop aimed to explore how analytical approaches and data used by various projects could be combined to respond to prioritised policy questions for a case study country. This process was supported by the presence of a small number of policy stakeholders and data partners from Nigeria, the case study country. Three exemplar policy questions were jointly identified on the first day of the workshop: 1) Why are we fortifying what we are fortifying? 2) How to make a case for scaling up rice fortification in Nigeria? 3) What minimum and maximum levels of micronutrients should be specified in Nigeria’s mandatory fortification standards? To achieve the workshop’s objective, three cross-project working groups were formed to plan and conduct analysis and develop evidence outputs to respond to these policy questions. Analysis was conducted using available household-level food consumption microdata from the 2018-19 Nigeria Living Standards Survey, preliminary summary results from the 2021 Nigeria Food Consumption and Micronutrient Survey and available 2011 individual-level food consumption microdata from the FAO/WHO GIFT Platform. Groups presented updates and outputs from their analysis work on each consecutive day of the workshop and received feedback and suggestions from other participants, led by the Nigerian policy representatives. Cross-cutting discussions focused on improving the communication and packaging of evidence products for policy use, and how to build capacity for analysts and researchers in Nigeria to utilise the soon-to-be-released National Food Consumption and Micronutrient Survey (NFCMS) in order to respond to policy questions. This selection of participants was not done with an aim to be, nor presumes to be representative of all views or policy stakeholders for fortification, nutrition policy or nutrition data analysis, either globally or in the Nigerian context. Many of the projects have workshops or meetings in Nigeria planned in their 2024 workplan to meet with a broad array of relevant stakeholders and invite their feedback into the individual pieces of analysis and any analytical outputs

    The human affectome

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    Over the last decades, the interdisciplinary field of the affective sciences has seen proliferation rather than integration of theoretical perspectives. This is due to differences in metaphysical and mechanistic assumptions about human affective phenomena (what they are and how they work) which, shaped by academic motivations and values, have determined the affective constructs and operationalizations. An assumption on the purpose of affective phenomena can be used as a teleological principle to guide the construction of a common set of metaphysical and mechanistic assumptions-a framework for human affective research. In this capstone paper for the special issue "Towards an Integrated Understanding of the Human Affectome", we gather the tiered purpose of human affective phenomena to synthesize assumptions that account for human affective phenomena collectively. This teleologically-grounded framework offers a principled agenda and launchpad for both organizing existing perspectives and generating new ones. Ultimately, we hope Human Affectome brings us a step closer to not only an integrated understanding of human affective phenomena, but an integrated field for affective research
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