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111.
It is well known that sport and exercise play an important role in stimulating site-specific bone mineral density (BMD). However, what is less well understood is how these benefits dissipate throughout the body. Hence, the aim of the present study was to compare the BMD (recorded at nine sites throughout the skeleton) of 106 male athletes (from nine sports) with that of 15 male non-exercising age-matched controls. Given that BMD is known to increase with body mass and peak with age, multivariate and univariate analyses of covariance were performed to compare the BMD of the nine sports groups with controls (at all sites) using body mass and age as covariates. Our results confirmed a greater adjusted BMD in the arms of the upper-body athletes, the right arm of racket players and the legs of runners (compared with controls), supporting the site-specific nature (i.e. specific to the externally loaded site) of the bone remodelling response (all P?<0.01). However, evidence that bone mass acquisition is not just site-specific comes from the results of the rugby players, strength athletes, triathletes and racket players. The rugby players' adjusted BMD was the greatest of all sports groups and greater than controls at all nine sites (all P?<0.01), with differences ranging from 8% greater in the left arm to 21% in the lumbar spine. Similarly, the strength athletes' adjusted BMD was superior to that of controls at all sites (P?<0.05) except the legs. The adjusted BMD of the triathletes was significantly greater than that of the controls in both the arms and the legs as well as the thoracic and lumbar spine. The racket players not only had significantly greater right arm BMD compared with the controls but also a greater BMD of the lumbar spine, the pelvis and legs. In contrast, the low-strain, low-impact activities of keep-fit, cycling and rowing failed to benefit BMD compared with the age-matched controls. These results suggest that sporting activities involving high impact, physical contact and/or rotational forces or strains are likely to convey significant benefits not only to the loaded sites, but also to other unloaded peripheral and axial sites throughout the skeleton. 相似文献
112.
Laura Chaddock Charles H. Hillman Matthew B. Pontifex Christopher R. Johnson Lauren B. Raine Arthur F. Kramer 《Journal of sports sciences》2013,31(5):421-430
Abstract Aerobically fit children outperform less fit peers on cognitive control challenges that involve inhibition, cognitive flexibility, and working memory. The aim of this study was to determine whether, compared with less fit children, more fit 9- and 10-year-old pre-adolescents exhibit superior performance on a modified compatible and incompatible flanker task of cognitive control at the initial time of fitness testing and approximately one year later. We found that more fit children demonstrated increased flanker accuracy at both test sessions, coupled with a superior ability to flexibly allocate strategies during task conditions that required different amounts of cognitive control, relative to less fit children. More fit children also gained a speed benefit at follow-up testing. Structural MRI data were also collected to investigate the relationship between basal ganglia volume and task performance. Bilateral putamen volumes of the dorsal striatum and globus pallidus volumes predicted flanker performance at initial and follow-up testing one year later. The present findings suggest that childhood aerobic fitness and basal ganglia volumes relate to cognitive control at the time of fitness testing and may play a role in cognitive performance in the future. We hope that this research will encourage public health and educational changes that will promote a physically active lifestyle in children. 相似文献
113.
Cleiton Augusto Libardi Giovana Verginia Souza Arthur Fernandes GÁspari Claudinei Ferreira Dos Santos Sabrina Toffoli Leite Rodrigo Dias 《Journal of sports sciences》2013,31(14):1573-1581
Abstract The purpose of this study was to evaluate the effects of moderate- to high-intensity resistance and concurrent training on inflammatory biomarkers and functional capacity in sedentary middle-aged healthy men. Participants were selected on a random basis for resistance training (n = 12), concurrent training (n = 11) and a control group (n = 13). They performed three weekly sessions for 16 weeks (resistance training: 10 exercises with 3 × 8–10 repetition maximum; concurrent training: 6 exercises with 3 × 8–10 repetition maximum, followed by 30 minutes of walking or running at 55–85% [Vdot]O2peak). Maximal strength was tested in bench press and leg press. The peak oxygen uptake ([Vdot]O2peak) was measured by an incremental exercise test. Tumour necrosis factor-α, interleukin-6 and C-reactive protein were determined. The upper- and lower-body maximal strength increase for both resistance (+42.52%; +20.9%, respectively) and concurrent training (+28.35%; +21.5%, respectively) groups (P = 0.0001).[Vdot]O2peak increased in concurrent training when comparing pre- and post-training (P = 0.0001; +15.6%). No differences were found in tumour necrosis factor-α and interleukin-6 for both groups after the exercise. C-reactive protein increased in resistance training (P = 0.004). These findings demonstrated that 16 weeks of moderate- to high-intensity training could improve functional capacity, but did not decrease inflammatory biomarkers in middle-aged men. 相似文献
114.
Alan M. Nevill Edward M. Winter Steve Ingham Adam Watts Georgios S. Metsios Arthur D. Stewart 《Journal of sports sciences》2013,31(9):1009-1016
Abstract The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm · (kg · m?2)?1) was greater than the BMI slope parameter for sports (2.62 mm · (kg · m?2)?1) and middle-distance runners (0.94 mm · (kg · m?2)?1) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research. 相似文献
115.
Ernest D. Michael Jr. Arthur Gallon Adran Adams 《Research quarterly for exercise and sport》2013,84(3):382-388
Abstract Members of the 1958–59 varsity basketball team at Santa Barbara and a control group of physical education majors not in training were tested each three weeks during a 17-week season of basketball competition on their response to a step test and to a cold pressor test. The results indicated that significant step test recovery pulse rate changes were made by the basketball players after three weeks of training. Maximum changes were found to occur after 17 weeks of training. The diastolic pressure response to the cold pressor test increased significantly (7 mmHg.) after six weeks of training and this was maintained for 17 weeks. The results indicated that a possible increased sensitivity or tone of the peripheral vessels resulted from physical training. 相似文献
116.
Victor Bekkers Henri Beunders Arthur Edwards Rebecca Moody 《The Information Society》2013,29(4):209-219
In November 2007, Dutch secondary school students revolted against a requirement known as the “1040-hour norm.” New Web technologies, like instant messaging, YouTube, and social networking sites, played an important role in the mobilization effort. In this article, the authors argue that these technologies facilitate a shift toward micromobilization by individuals and small groups. In this “1040-hour norm” case study, the authors analyze how the course of the political agenda-setting process is being transformed through the interplay between processes of meso- and micromobilization, and through new micro-to-mass media crossover effects. When supported by micromedia, the effects of micromobilization can create strategic surprises for traditional intermediary organizations and policymakers. 相似文献
117.
To examine the development of triplets, 23 sets of triplets were matched with 23 sets of twins and 23 singletons (N=138). Maternal sensitivity was observed at newborn, 3, 6, and 12 months, and infants' cognitive and symbolic skills at 1 year. Triplets received lower maternal sensitivity across infancy and exhibited poorer cognitive competencies compared with singletons and twins. The most medically compromised triplet showed the lowest regulation, received lower maternal sensitivity, and demonstrated the weakest outcomes compared with siblings. Structural modeling charted three levels of influence on cognitive outcomes: direct, indirect, and contextual. The triplet ecology provides a context for assessing the relations among infant inborn dispositions, the rearing environment, and the role of exclusive parenting in development. 相似文献
118.
Arthur L. Benton 《Annals of dyslexia》1984,34(1):69-85
Impairment in spatial thinking has figured prominently as an assumed cause of developmental reading disability. The empirical
findings relevant to the idea, with special reference to right-left orientation, visuomotor and visuoconstructive performances,
and finger recognition are examined. It is concluded that, although some dyslexic children do show spatial disabilities, there
is little evidence to support the existence of a visuospatial type of developmental dyslexia.
Presented at the 33rd Annual Conference of The Orton Dyslexia Society, San Diego, California, November 1983. 相似文献
119.
Dumar David D. White Arthur L. Helgeson Stanley L. 《Journal of Science Education and Technology》1994,3(3):187-200
This study investigated HyperCard as a tool for assessment in science education and determined whether or not a HyperCard assessment instrument could differentiate between expert and novice student performance (balancing stoichiometric equations) in science education. Five chemical equations were presented by traditional pen-paper and by a HyperCard (Hyperequation) program. Thirty honors (expert) and 30 regular (novice) chemistry students were randomly divided into HyperCard and traditional pen-paper groups of 15 students each. Scoring was based on five dependent variables: performance scores, number of attempts, rate of attempts, time on task, and correctness. Correlation results indicated that students with high performance scores correctly balanced more equations, required fewer attempts to balance equations, and required less time per attempt than did students with low performance scores. MANOVA results showed that performance scores and correctness scores for both experts and novice were significantly higher on HyperCard compared to pen-paper assessment; the novice scores on HyperCard nearly equaled the expert pen-paper assessment scores. Significant interactions were found for time on task and for correctness. The results suggest that HyperCard can be a suitable tool for assessment in science education and that such an instrument can differentiate between expert and novice student performance. 相似文献
120.
Arthur M. Cohen 《Research in higher education》1976,5(4):313-319
Using on-campus facilitators to distribute and retrieve an 11-page questionnaire administered to a nationwide sample of humanities faculty and nonhumanities department chairmen in two-year colleges resulted in an 84% return rate. The 2,000 subjects were drawn from 156 junior/community colleges selected on the basis of geographic locale and type of control. Secondary stratification variables included college size, organization, and curriculum emphasis. Accurate rosters of full-time and part-time faculty were generated from class schedules. Pilot procedures, selection of the college and faculty samples, and the use of facilitators are described. 相似文献