The effect of beetroot juice supplementation on repeat-sprint performance in hypoxia     

Georgina L. Kent  Brian Dawson  Lars R. McNaughton  Gregory R. Cox  Louise M. Burke  Peter Peeling 《Journal of sports sciences》2019,37(3):339-346

This investigation assessed the effect of dietary nitrate (NO₃^?) supplementation, in the form of beetroot juice (BR), on repeat-sprint performance in normoxia and normobaric hypoxia. 12 male team-sport athletes (age 22.3 ± 2.6 y, VO_2peak 53.1 ± 8.7 mL.kg^?1.min^?1) completed three exercise trials involving a 10 min submaximal warm-up and 4 sets of cycling repeat-sprint efforts (RSE; 9 × 4 s) at sea level (CON), or at 3000 m simulated altitude following acute supplementation (140 mL) with BR (HYP_BR; 13 mmol NO₃^?) or NO₃^–depleted BR placebo (HYP_PLA). Peak (PPO) and mean (MPO) power output, plus work decrement were recorded during the RSE task, while oxygen consumption (VO₂) was measured during the warm-up. There were no significant differences observed between HYP_BR and HYP_PLA for PPO or MPO; however, work decrement was reduced in the first RSE set in HYP_BR compared with HYP_PLA. There was a moderate effect for VO₂ to be lower following BR at the end of the 10 min warm-up (ES = 0.50 ± 0.51). Dietary NO₃^? may not improve repeat-sprint performance in hypoxia but may reduce VO₂ during submaximal exercise. Therefore, BR supplementation may be more effective for performance improvement during predominantly aerobic exercise.  相似文献   

Evening electronic device use and sleep patterns in athletes     

Maddison J. Jones  Brian Dawson  Daniel F. Gucciardi  Peter R. Eastwood  Joanna Miller  Shona L. Halson 《Journal of sports sciences》2019,37(8):864-870

The present study aimed to investigate pre-sleep behaviours (including evening electronic device use) and sleep quantity in well-trained athletes. Seventy well-trained athletes (44 females, 26 males) aged 21 ± 4 y from a range of team and individual sports were asked to complete an online sleep diary for 7 days. The sleep diary included questions about pre-sleep behaviours (e.g. napping, caffeine intake), electronic device use in the 2 h prior to bedtime (e.g. type of device and duration of use) and sleep (e.g. time in bed, sleep onset latency). On average, athletes spent 8:20 ± 1:21 h in bed each night. Associations between age, time in bed and sleepiness suggested that younger athletes spent more time in bed (B = -0.05, p = 0.001) but felt sleepier (r = -0.32, p < 0.01) than older athletes. On average, athletes mostly used electronic devices for 0–30 min prior to sleep. The use of multiple devices in the evening was associated with more perceived difficulty in falling asleep (B = 0.22, p = 0.03), but no associations existed with other sleep variables. In summary, younger athletes may require later start times or improved sleep quality to resolve excessive sleepiness.  相似文献   

Facilitators and Barriers to Movement Integration in Elementary Classrooms: A Systematic Review     

Robert Dan Michael  Cate A. Egan  Lynda Nilges  Ali Brian  Robert Johnson 《Research quarterly for exercise and sport》2019,90(2):151-162

Purpose: A systematic review was conducted to identify facilitators and barriers to movement integration (MI) in elementary school classrooms. Method: Online databases (Educational Resources Information Center, Google Scholar, PsycINFO, and PubMed) served as data sources for the study. Following the PRISMA guidelines, relevant published research on MI was identified and screened for inclusion in a qualitative synthesis. Content analysis of the included articles (N = 28) was used to identify themes of MI facilitators and barriers. Facilitators and barriers were then categorized using a social-ecological framework. Results: A total of 12 themes of MI facilitators and barriers were identified and categorized into two social-ecological levels: institutional factors (e.g., administrative support, resources) and intrapersonal factors (e.g., teacher confidence, ease of implementation). Conclusion: This review can inform research and practice aimed at supporting the implementation of MI in elementary classrooms.  相似文献   

SKIPing with teachers: an early years motor skill intervention     

Ali Brian  Jacqueline D. Goodway  Jessica A. Logan  Sue Sutherland 《Physical Education & Sport Pedagogy》2017,22(3):270-282

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Sand training: Exercise-induced muscle damage and inflammatory responses to matched-intensity exercise     

Henry Brown  Brian Dawson  Martyn J. Binnie  Hugh Pinnington  Marc Sim  Tristan D. Clemons 《European Journal of Sport Science》2017,17(6):741-747

This study compared markers of muscle damage and inflammation elevated by a matched-intensity interval running session on soft sand and grass surfaces. In a counterbalanced, repeated-measures and crossover design, 10 well-trained female athletes completed 2 interval-based running sessions 1 week apart on either a grass or a sand surface. Exercise heart rate (HR) was fixed at 83–88% of HR maximum. Venous blood samples were collected pre-, post- and 24?h post-exercise, and analysed for myoglobin (Mb) and C-reactive protein (CRP). Perceptual ratings of exertion (RPE) and muscle soreness (DOMS) were recorded immediately post- and 24?h post-exercise. A significant time effect showed that Mb increased from pre- to post-exercise on grass (p?=?.008) but not on sand (p?=?.611). Furthermore, there was a greater relative increase in Mb on grass compared with that on sand (p?=?.026). No differences in CRP were reported between surfaces (p?>?.05). The HR, RPE and DOMS scores were not significantly different between conditions (p > .05). These results suggest that in response to a matched-intensity exercise bout, markers of post-exercise muscle damage may be reduced by running on softer ground surfaces. Such training strategy may be used to minimize musculoskeletal strain while still incurring an equivalent cardiovascular training stimulus.  相似文献   

The validity and reliability of a sample of 10 Wattbike cycle ergometers     

Barney Wainwright  Carlton Brian Cooke  John Paul O’Hara 《Journal of sports sciences》2017,35(14):1451-1458

ABSTRACT

The purpose of the study was to assess the validity and inter-bike reliability of 10 Wattbike cycle ergometers, and to assess the test–retest reliability of one Wattbike. Power outputs from 100 to 1000 W were applied using a motorised calibration rig (LODE) at cadences of 70, 90, 110 and 130 rev · min^?1, which created nineteen different intensities for comparison. Significant relationships (P < 0.01, r² = 0.99) were found between each of the Wattbikes and the LODE. Each Wattbike was found to be valid and reliable and had good inter-bike agreement. Within-bike mean differences ranged from 0.0 W to 8.1 W at 300 W and 3.3 W to 19.3 W at 600 W. When taking into account the manufacturers stated measurement error for the LODE (2%), the mean differences were less than 2%. Comparisons between Wattbikes at each of the nineteen intensities gave differences from 0.6 to 25.5 W at intensities of 152 W and 983 W, respectively. There was no significant difference (P > 0.05) between the measures of power recorded in the test–retest condition. The data suggest that the Wattbike is an accurate and reliable tool for training and performance assessments, with data between Wattbikes being able to be used interchangeably.  相似文献   

Computerized Agility Training Improves Change-of-Direction and Balance Performance Independently of Footwear in Young Adults     

Max R. Paquette  Brian K. Schilling  Joshua D. Bravo  Shelby A. Peel  Yuhua Li  Robert J. Townsend 《Research quarterly for exercise and sport》2017,88(1):44-51

Understanding the effects of training in different footwear on sporting performance would be useful to coaches and athletes. Purpose: This study compared the effects of computerized agility training using 3 types of footwear on change-of-direction and balance performance in young adults. Method: Thirty recreationally active young adults (M_age = 22.8 ± 3.1 years; M_height = 1.71 ± 0.7 m; M_bodymass = 73.4 ± 10.3 kg) were randomly assigned to a 6-week computerized agility training intervention in 1 of 3 footwear groups (n = 10/group): barefoot, minimal footwear, or traditional shoes. Participants had no previous barefoot or minimal-footwear training experience. Dependent variables included change-of-direction test time to completion, Star Excursion Balance Test, and single-leg stability evaluation. Testing was performed at the start of the training program, after 2 weeks, after 4 weeks, and at the end of the training program. Results: No group or time interactions were found for any of the dependent variables. Time main effects were observed for the performance measures of change of direction, Star Excursion, and single-leg-with-eyes-open stability evaluation. Participants improved in all 3 tests as early as 2 weeks into the intervention, with improvements continuing through the entire 6-week intervention. Conclusions: The lack of interaction and footwear effects suggests that agility and balance improvements during foot agility training are independent of footwear in a recreationally active young-adult population. Computerized agility training improves change-of-direction and balance performance within 2 weeks of training implementation. Future studies should consider footwear training effects in different populations, including frail older adults and athletes.  相似文献   

Correction to: Computerized Agility Training Improves Change-of-Direction and Balance Performance Independently of Footwear in Young Adults     

Max R. Paquette  Brian K. Schilling  Joshua D. Bravo  Shelby A. Peel  Yuhua Li  Robert J. Townsend 《Research quarterly for exercise and sport》2017,88(2)

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Gender Talk: The Struggle for Women's Equality in African-American Communities     

Francescina R. Jackson 《Multicultural Perspectives》2013,15(1)

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A Review of “African American Actresses: The Struggle for Visibility, 1900–1960”     

Francesina R. Jackson 《Multicultural Perspectives》2013,15(4):227-228

The Boston Marathon bombings in April 2013 created a new kind of discomfort in the United States about “self-radicalized” terrorists, particularly related to Muslim immigrants. The two suspected bombers, brothers with Chechen backgrounds, had attended U.S. public schools. News media portrayed the brothers as “immigrants” and often showed them as having a struggle between their Chechen and U.S. identities. This article proposes that educators consider reframing the talk and discourses about immigrants and immigration toward a more complex understanding of transnationalism. The author demonstrates her work as a former English language learner teacher and her current research in the area of transnationalism to argue for educators to teach meaningfully about this concept. The goal, the author argues, is to help create a deeper understanding of newer arrivals to the United States so that the more newly arrived have greater choices about who they become and the identities they perform.  相似文献