Electronic publishing in science     

David J. Brown 《Learned Publishing》1996,9(4):233-236

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The High School Mascot as Icon     

Christopher D. Geist 《Journal of American culture (Malden, Mass. : 2003)》1978,1(3):569-573

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Using the internet in the K-12 classroom:     

Christopher?EssexEmail author 《TechTrends》2002,46(3):23-27

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Maximal-intensity isometric and dynamic exercise performance after eccentric muscle actions   总被引：3，自引：2，他引：1  

Byrne C  Eston R 《Journal of sports sciences》2002,20(12):951-959

A well-documented observation after eccentric exercise is a reduction in maximal voluntary force. However, little is known about the ability to maintain maximal isometric force or generate and maintain dynamic peak power. These aspects of muscle function were studied in seven participants (5 males, 2 females). Knee extensor isometric strength and rate of fatigue were assessed by a sustained 60 s maximal voluntary contraction at 80 degrees and 40 degrees knee flexion, corresponding to an optimal and a shortened muscle length, respectively. Dynamic peak power and rate of fatigue were assessed during a 30 s Wingate cycle test. Plasma creatine kinase was measured from a fingertip blood sample. These variables were measured before, 1 h after and 1, 2, 3 and 7 days after 100 repetitions of the eccentric phase of the barbell squat exercise (10 sets x 10 reps at 80% concentric one-repetition maximum). Eccentric exercise resulted in elevations in creatine kinase activity above baseline (274+/-109 U x l(-1); mean +/- s(x)) after 1 h (506+/-116 U x l(-1), P < 0.05) and 1 day (808+/-117 U x l(-1), P < 0.05). Isometric strength was reduced (P < 0.05) for 7 days (35% at 1 h, 5% at day 7) and the rate of fatigue was lower (P < 0.05) for 3 days at 80 degrees and for 1 day at 40 degrees. Wingate peak power was reduced to a lesser extent (P < 0.05) than isometric strength at 1 h (13%) and, although the time course of recovery was equal, the two variables differed in their pattern of recovery. Eccentrically exercised muscle was characterized by an inability to generate high force and power, but an improved ability to maintain force and power. Such functional outcomes are consistent with the proposition that type II fibres are selectively recruited or damaged during eccentric exercise.  相似文献   

Anxiety, arousal and visual attention: a mechanistic account of performance variability     

Janelle CM 《Journal of sports sciences》2002,20(3):237-251

Despite extensive research devoted to determining the nature of the relationship between stress and performance, there has been little systematic examination of the mechanisms underlying this relationship. Recently, researchers have begun to empirically address the attentional mechanisms underlying theoretical accounts of how stress, anxiety and arousal influence performance. Given the critical role of visual attention to sport expertise, this paper focuses primarily on literature dealing with how visual cues are differentially identified and processed when performers are anxious. Emerging evidence indicates that gaze behaviour tendencies are reliably altered when performers are anxious, leading to inefficient and often ineffective search strategies. Alterations of these visual search indices are addressed in the context of both self-paced and externally paced sports events. Recommendations concerning the utility of perceptual training programmes and how these training programmes might be used as anxiety regulation interventions are discussed. The theoretical implications and directions for future research are also addressed.  相似文献   

Motivation for physical activity in young people: entity and incremental beliefs about athletic ability     

Biddle SJ  Wang CK  Chatzisarantis NL  Spray CM 《Journal of sports sciences》2003,21(12):973-989

Three studies are reported of children and youth aged 11-19 years (n = 3478) examining the nature of beliefs about athletic ability. Drawing on related research in academic, moral and stereotyping domains, development of a psychometric instrument assessing athletic ability beliefs is detailed. Support was found for a multidimensional hierarchical structure that is invariant across age and gender. Confirmatory factor analysis revealed a structure comprising two higher-order factors of entity and incremental beliefs underpinned by beliefs that athletic ability is stable and a gift (entity), and is open to improvement and can be developed through learning (incremental). Incremental beliefs, indirectly through a task goal orientation, and entity beliefs directly, predicted self-reported amotivation towards physical education and sport. On the other hand, enjoyment of physical activity in youth was predicted directly by task orientation and incremental beliefs. Predictions concerning the moderating role of perceived competence were not supported. Our findings highlight the importance of ability beliefs and goals in understanding the determinants of physical activity in children and youth.  相似文献   

Mechanisms of attentional cueing during observational learning to facilitate motor skill acquisition     

Janelle CM  Champenoy JD  Coombes SA  Mousseau MB 《Journal of sports sciences》2003,21(10):825-838

We examined the effectiveness of different cueing conditions during observational learning of a soccer accuracy pass. Sixty participants (30 males, 30 females) were randomly assigned and stratified by sex into one of six groups: discovery learning, verbal instruction, video model with visual cues, video model with verbal cues, video model with visual and verbal cues, and video model only. Each participant completed eight blocks of 10 trials each, with trial blocks 1 and 2 representing the practice phase (no manipulation), trial blocks 3, 4, 5 and 6 the acquisition phase (manipulation administered) and trial blocks 7 and 8 the retention phase (24 h after acquisition, with no manipulation). Absolute error, variable error and kicking form were recorded. The results indicated that those who used video modelling with visual and verbal cues collectively displayed less error and more appropriate form across acquisition and retention trial blocks compared with other groups. Our findings suggest that verbal information in addition to visual cues enhances perceptual representation and retention of modelled activities to improve task reproduction capabilities. Future research directions are proposed with implications for both direct and indirect perception accounts of skill acquisition through observed behaviours.  相似文献   

Leisure time physical activity in Australian women: relationship with well being and symptoms   总被引：5，自引：0，他引：5  

Brown WJ  Mishra G  Lee C  Bauman A 《Research quarterly for exercise and sport》2000,71(3):206-216

This paper explores the association between moderate levels of physical activity (PA) and health benefits in well being and symptoms such as tiredness, back pain, and constipation. Participants in the Australian Longitudinal Study on Women's Health, 14,502 young women (ages 18-23 years), 13,609 middle-age women (45-50 years), and 11,421 older women (ages 70-75 years), answered questions about vigorous and less vigorous exercise (used to determine a physical activity score), well being (SF-36), symptoms, and medical conditions. There were significant associations between the PA score and SF-36 in each cohort. Odds ratios (OR) for a range of symptoms and conditions were lower for women who reported low to moderate activity than for sedentary women, for example, for young women or for constipation = 0.76 (CI, 0.65-0.89), for middle-age women or for tiredness = 0.70 (0.63-0.78). There was no threshold of PA at which health benefits increased significantly. Although cross-sectional, the findings suggest that low-to-moderate levels of exercise are associated with a range of health benefits for women of all ages. These preliminary findings will be followed up during the longitudinal study.  相似文献   

POLLING AS A MEANS TOWARD PRESIDENTIAL AUTONOMY: EMIL HURJA, HADLEY CANTRIL AND THE ROOSEVELT ADMINISTRATION     

Eisinger  Robert M.; Brown  Jeremy 《Int. Journal of Public Opinion Research》1998,10(3):237-256

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Letter to the editor     

Christopher Zielinski 《Learned Publishing》1998,11(2):88-89

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