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Purpose: This study was a 2-phase activist research project aimed at co-creating a prototype pedagogical model for working with youth from socially vulnerable backgrounds in a sport context. This article addresses the learning aspirations (learning outcomes) that emerged when we created spaces for youth to develop strategies to manage the risks they face in their community. Method: This study took place in a socially and economically disadvantaged neighborhood in a Brazilian city where we worked with a group of 17 boys aged 13 to 15 years old, 4 coaches, a pedagogic coordinator, and a social worker. During a 6-month period, we collected multiple sources of data including field journal entries/observations (38) and audio records of youth work sessions (18), coaches' work sessions (16), combined coaches and youth work sessions (3), and meetings between the lead and the 2nd author for debriefing and planning sessions (36). Results: By using an activist approach, 4 learning aspirations emerged: becoming responsible/committed, learning from mistakes, valuing each other's knowledge, and communicating with others. Conclusion: Findings suggest there is a need for more sports programs that start from young people's concrete needs and life situations and look to create places for youth to see alternative possibilities and take action.  相似文献   
633.
Background: The aim of this systematic review was to investigate the association of different components of physical fitness on cognitive performance (CP) and academic performance (AP) in adolescents, taking into account potential confounders. Method: Studies were identified in four databases (Pubmed, SportDiscus, Web of Science, and ProQuest) from January 2005 through to January 2015. A total of 21 articles met the inclusion criteria. Results: 8 studies showed association between physical fitness and CP, and 11 studies with AP. Cardiorespiratory fitness, speed-agility, motor coordination, and perceptual-motor skill are the highest measures associated with CP and AP. However, the findings on strength and flexibility are unclear. Finally, 62% of the 21 studies used confounders. The most controlled confounder were socioeconomic status, fatness, pubertal status, sex, and age. Conclusion: Fitness is associated with higher CP and AP. More research is needed in order to understand the causes of the differential effect of physical fitness components on CP and AP.  相似文献   
634.
The aim of this study was to identify the effects of adding spatial references during football small-sided games in youth players’ tactical and physical performance. Twelve under-15 players performed a Gk+ 6v6+ Gk game under two playing conditions: (i) without spatial references (CONTROL condition); (ii) with spatial references, by dividing equally the pitch into three corridors and three sectors (experimental situation, LINES). Players’ positional data was used to compute time-motion and tactical-related variables. The results revealed that performance under LINES situation increased the regularity in the zones occupied (~14%, Cohen’s d: 0.5; ±0.3; p = 0.003) and in the distance between teammates’ dyads (~19%, 0.9; ±0.2; p < 0.001). Oppositely, LINES condition decreased the longitudinal synchronization of players’ displacements (0.4; ±0.2; p = 0.002), players’ average speed (0.5; ±0.3; p = 0.002) and distance covered at lower (0.9; ±0.3; p < 0.001) and moderate speed (0.5; ±0.3; p < 0.001). Adding spatial references seems to promote a more structured pattern of play and increase positional regularity. However, coaches should be aware that this constraint may decrease the synchronization between players. Overall, these findings may be generalized to most invasion team sports.  相似文献   
635.
The coincidence-anticipation timing (CAT) task assesses one facet of cognitive and motor performance and is used to understand the human visuo-motor system involved in intercepting the moving object. To assess the test–retest reliability and the concurrent validity in the Bridge Games package (Bridge) developed to assess the CAT task, the scores of 224 healthy subjects (M = 52.2, SD = 19.5 years old) were measured using the Bridge and the ‘gold standard’ Bassin Anticipation Timer (Bassin). A mean block of absolute, constant, and variable errors was calculated. Reliability and validity were expressed using intraclass correlation coefficients (ICC2,k), standard error of measurement, minimal detectable change, and Pearson’s correlation. Reliability was good to excellent for all blocks (.73 ≤ ICC ≤ .88), and the validity was good to excellent when compared using Pearson’s correlation coefficient, suggesting that the two tests may have similar properties. Bridge is an alternative to existing clinical tests for the CAT task.  相似文献   
636.
The effects of training on FNDC5/irisin and its association with fitness and metabolic marker improvements induced by training have been poorly investigated in humans. Thus, the present study assessed the effects of combined training (CT) on FNDC5/irisin levels, metabolic markers and fitness adaptations in obese men. Middle-age obese men (age 49.13?±?5.75, body mass index (BMI) 30.86?±?1.63) were randomly distributed in the CT group (n?=?12) and control group (CG n?=?10). The CT consisted of strength followed by aerobic training, 3 times/week, for 24 weeks. Body composition, physical fitness, plasma FNDC5/irisin, biochemical markers and metabolic scores/index were evaluated. CT maintained FNDC5/irisin levels (µg/mL) (pre: 4.15?±?0.32, post: 4.21?±?0.32; p?=?.96) and improved body composition, metabolic and physical fitness markers. In the CG, decreased FNDC5/irisin (µg/mL) (pre: 4.36?±?0.23, post: 3.57?±?0.94; p?=?.01) and reduced strength (supine exercise/kg) (pre: 71?±?14.7, post: 60.1?±?14.05; p?<?.01) were observed, along with a trend to increase HOMA-IR (pre: 2.63?±?1.11, post: 3.14?±?1.27; p?=?.07) and other indicators of metabolic deterioration. An inverse correlation was found between the change (Δ%) in levels of FNDC5/irisin and Δ% glucose, Δ% total cholesterol, Δ% triglycerides and Δ% waist circumference, in addition to a positive relation with Δ% muscle strength. In conclusion, CT maintained FNDC5/irisin levels and provided metabolic and fitness benefits. The correlation between FNDC5/irisin changes and metabolic parameters, as well as the FNDC5/irisin reduction associated with fitness and metabolic worsening in the CG, suggests a relationship between FNDC5/irisin and a healthy metabolic status in humans.  相似文献   
637.
This study investigated the effects of different reduced strength training (RST) frequencies on half-squat 1 RM and quadriceps cross-sectional area (QCSA). Thirty-three untrained males (24.7?±?3.9 years; 1.73?±?0.08?m; 74.6?±?8.4?kg) underwent a 16-week experimental period (i.e. eight weeks of strength training [ST] followed by additional eight weeks of RST). During the ST period, the participants performed 3–4 sets of 6–12 RM, three sessions/week in half-squat and knee extension exercises. Following ST, the participants were randomly allocated to one of three groups: reduced strength training with one (RST1) or two sessions per week (RST2), and ceased training (CT). Both RST1 and RST2 groups had their training frequency and total training volume-load (i.e. RST1?=?50.3% and RST2?=?57.1%) reduced, while the CT group stopped training completely. Half-squat 1 RM (RST1?=?27.9%; RST2?=?26.7%; and CT?=?28.4%) and QCSA (RST1?=?6.1%; RST2?=?6.9%; and CT?=?5.8%) increased significantly (p?<?.05) in all groups after eight weeks of ST. No significant changes were observed in 1 RM and QCSA for RST1 and RST2 groups after the RST period, while the CT group demonstrated a decrease in half-squat 1 RM (22.6%) and QCSA (5.4%) when compared to the ST period (p?<?.05). In conclusion, different RST frequencies applied were able to maintain muscle mass and strength performance obtained over the regular ST period. Thus, it appears that RST frequency does not affect the maintenance of muscle mass and strength in untrained males, as long as volume-load is equated between frequencies.  相似文献   
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This paper analyzes the determinants of donations to public libraries testing the following hypothesis: Is there a crowd out effect from government funding of public libraries? I look at novel data, the Public Library Survey, and use an unbalanced panel of public libraries across the USA from 2000 to 2013. The results suggest a crowd in effect with an inverted U shape in all levels of government. Local government is associated with 4–6 cents increase in donations, state government with 20–23 cents increase, and federal government with 75 cents to 1 dollar and 33 cents.  相似文献   
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