生物节律与运动表现          下载免费PDF全文

康杰  刘畅 《体育科研》2020,(2):1-17

人体内几乎所有的生理生化过程都遵循着生物节律。对于人类而言,视交叉上核根据日出日落调节睡眠-觉醒周期和其他日常生物节律。除其他因素外,这种昼夜变化已被证明对与运动表现有关的关键生理过程具有调节作用。最佳运动状态一般出现在傍晚,与核心体温的最佳状态相一致。核心体温的升高已被证明可以提高能量代谢,改善肌肉适应性,促进肌动蛋白-肌球蛋白的交叉桥接。研究还表明,如果在运动员表现最好的时间段安排训练,可以提升运动员的训练适应性。在研究生物节律对运动表现的影响时,除了考虑昼夜变化外,个人对运动时间(白天或夜间)的偏好也是一个重要因素。经常参加国际比赛的运动员会经历生物节律的改变,这对他们的身体健康和运动表现不利。因此,那些更容易受到时差影响的运动员可以考虑使用适当的应对策略来更快地调整生物节律,确保最佳竞技状态。  相似文献   

片形吸虫成虫虫体抗原制备及ELISA实验研究     

陈凤  李科荣  杨敬  郝明明  罗家军  刘榆华 《大理师专学报》2014,(10):32-36

目的：研究人体片形吸虫病ELISA检测试剂盒的检测效果。方法：采用云南大理本地采集的牛体片形吸虫成虫制备可溶性粗抗原,包被反应板,采用人体片形吸虫病ELISA法（FAWA-ELISA）进行研究,分别检测26份片形吸虫患者血清、102份其他寄生虫病患者血清和25份健康人血清,评价检测试剂盒的检测效果。结果：检测试剂盒的敏感性为100.0%、特异性分别为95.28%（95%CI：98.9%～91.2%）,约登指数分别为0.95。结论：FAWA-ELISA试剂盒检测效果较好,且成本相对较低,可适宜用于云南片形吸虫病流行区流行病学筛查,减轻病原学检测的工作量。  相似文献   

Effects of latissimus dorsi length on shoulder flexion in canoeists,swimmers, rugby players,and controls     

《运动与健康科学(英文)》2014,3(1):60-63

BackgroundShoulder flexion requires an optimal length of the latissimus dorsi muscle in order to allow full lateral rotation of the humerus and upward scapular rotation. If shoulder flexion (in an externally rotated position) is restricted, this may predispose the individual to shoulder pathology. Sports such as swimming and canoeing have increased shoulder injuries and require high levels of latissimus dorsi muscle activity, which may create muscle hypertrophy and increased stiffness, resulting in a loss of muscle length. The objective of this study was to investigate if differences are present in shoulder flexion in internally and externally rotated positions across different sports (swimming, canoeing, and rugby) and a non-sporting control group.MethodsOne hundred subjects (40 physically active controls, 25 professional Rugby Union players, 20 elite, national-level canoeists (slalom), and 15 elite, national-level swimmers) participated in this study. Shoulder flexion range of motion was measured using a standard goniometer, with the arm elevated in either full external or internal rotation.ResultsA significant difference in shoulder flexion range was observed between canoeists and swimmers, canoeists and controls, rugby players and canoeists, rugby players and swimmers, and controls and swimmers in the external rotation position (p < 0.017), but not between controls and rugby players (p = 0.12). For the internal rotation position, swimmers significantly differed from canoeists, rugby players, and controls (p < 0.017), but there were no significant differences between rugby players, canoeists, and controls (p > 0.07).ConclusionThis study found that the length of the latissimus dorsi differs between sports and controls in accordance with the specific physical demands of their sport.  相似文献   

Acute kinematic and kinetic adaptations to wearable resistance during vertical jumping     

Paul Macadam  Kim D. Simperingham  John B. Cronin  Grace Couture  Chloe Evison 《European Journal of Sport Science》2017,17(5):555-562

One variation of vertical jump (VJ) training is resisted or weighted jump training, where wearable resistance (WR) enables jumping to be overloaded in a movement specific manner. A two-way analysis of variance with Bonferroni post hoc contrasts was used to determine the acute changes in VJ performance with differing load magnitudes and load placements. Kinematic and kinetic data were quantified using a force plate and contact mat. Twenty sport active subjects (age: 27.8?±?3.8 years; body mass (BM): 70.2?±?12.2?kg; height: 1.74?±?0.78?m) volunteered to participate in the study. Subjects performed the counter movement jump (CMJ), drop jump (DJ) and pogo jump (PJ) wearing no resistance, 3% or 6% BM affixed to the upper or lower body. The main finding in terms of the landing phase was that the effect of WR was non-significant (P?>?.05) on peak ground reaction force. With regard to the propulsive phase the main findings were that for both the CMJ and DJ, WR resulted in a significant (P?<?.05) decrease in jump height (CMJ: ?12% to ?17%, DJ: ?10% to ?14%); relative peak power (CMJ: ?8% to ?17%, DJ: ?7% to ?10%); and peak velocity (CMJ: ?4% to ?7%, DJ: ?3% to ?8%); while PJ reactive strength index was significantly reduced (?15% to ?21%) with all WR conditions. Consideration should be given to the inclusion of WR in sports where VJ’s are important components as it may provide a novel movement specific training stimulus.

Highlights

• WR of 3 or 6 % BM provided a means to overload the subjects in this study resulting in decreased propulsive power and velocity that lead to a reduced jump height and landing force.

• Specific strength exercises that closely mimic sporting performance are more likely to optimise transference, therefore WR with light loads of 3–6% body mass (BM)appear a suitable tool for movement specific overload training and maximising transference to sporting performance.

• Practitioners can safely load their athletes with upper or lower body WR of 3–6% BM without fear of overloading the athletesover and above the landing forces they are typically accustomed too.

• As a training stimulus it would seem the WR loading provides adequate overload and athletes should focus on velocity of movement to improve power output and jump height i.e. take-off velocity.

  相似文献   

Simultaneous testing of four decades of academic self-concept models     

《Contemporary educational psychology》2017

In separate studies on academic self-concept, previous research has shown: (1) the distinctiveness of a cognitive and an affective component, (2) the domain specificity of self-concepts, (3) the reciprocal effects of self-concept and achievement, (4) the internal/external frame of reference in self-concept development, (5) the reciprocal effects of the internal/external frame of reference, (6) the big-fish-little-pond effect, and (7) the interrelatedness of self-concepts in similar domains. The present study demonstrates that all of these seven findings are replicable and may be synthesized in a single study with a sample of students in Singapore. Secondary 1 students (7th graders; N = 275) were surveyed with 24 items about their academic self-concepts in physics, English, and math in two components (cognitive and affective), and their respective achievement scores were recorded over two time points. Confirmatory factor analysis found that the cognitive and affective components of academic self-concept were separable. The students’ self-concepts in different curriculum domains were distinct, supporting the domain specificity of self-concepts. The frame of reference and reciprocal effects were both supported, but only for the cognitive component of self-concept. Positive and statistically significant correlations between physics and math suggest that these curriculum domains were interrelated. Results of self-concept studies in schools can encourage and guide the design of interventions that could enhance students’ self-concept for positive sustainable effects on desirable educational outcomes. Attempts to improve learning outcomes should emphasize an enhancement of specific components of academic self-concept in domain-specific and related curriculum domains for optimal effects.  相似文献   

论运动训练的特异性处方   总被引：2，自引：0，他引：2  

马继政 《安徽体育科技》2010,31(1):27-30

运动训练是一个生理性的刺激,长期训练可产生生理上的适应。特异性原则作为运动训练和评定的基本原则之一,一直受到广泛的关注和研究。综述和评估了有氧耐力训练、集体类的竞技运动项目、力量和爆发力训练等特异性处方。特异性原则实际应用不是绝对的,在分子水平,特异性原则内在分子变化的机制不断被发现和证实,新的理论的发现可能为运动训练的特异性处方制定提供帮助。  相似文献   

从海外大学生的特殊性探索其管理策略     

余香莲 《丽水学院学报》2009,31(6):91-94

通过与大陆学生在教育背景、文化背景、家庭环境及教育模式上的比较,了解海外大学生的特殊性,并从其特殊性出发,鼓励学生、重视学生,接纳学生、理解学生,对其进行个性化管理以及情绪疏导,从心理上走近学生,并通过形式多样的学生活动增强学生的凝聚力,充分调动海外大学生的创造性和无限潜力。  相似文献   

Diagnostic accuracy of UriSed automated urine microscopic sediment analyzer and dipstick parameters in predicting urine culture test results     

Ka?an Huysal  Yasemin U. Budak  Ayse Ulusoy Karaca  Murat Aydos  Serdar Kahvecio?lu  Mehtap Bulut  Murat Polat 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(2):211-217

Introduction

Urinary tract infection (UTI) is one of the most common types of infection. Currently, diagnosis is primarily based on microbiologic culture, which is time- and labor-consuming. The aim of this study was to assess the diagnostic accuracy of urinalysis results from UriSed (77 Electronica, Budapest, Hungary), an automated microscopic image-based sediment analyzer, in predicting positive urine cultures.

Materials and methods:

We examined a total of 384 urine specimens from hospitalized patients and outpatients attending our hospital on the same day for urinalysis, dipstick tests and semi-quantitative urine culture. The urinalysis results were compared with those of conventional semi-quantitative urine culture.

Results:

Of 384 urinary specimens, 68 were positive for bacteriuria by culture, and were thus considered true positives. Comparison of these results with those obtained from the UriSed analyzer indicated that the analyzer had a specificity of 91.1%, a sensitivity of 47.0%, a positive predictive value (PPV) of 53.3% (95% confidence interval (CI) = 40.8–65.3), and a negative predictive value (NPV) of 88.8% (95% Cl = 85.0–91.8%). The accuracy was 83.3% when the urine leukocyte parameter was used, 76.8% when bacteriuria analysis of urinary sediment was used, and 85.1% when the bacteriuria and leukocyturia parameters were combined. The presence of nitrite was the best indicator of culture positivity (99.3% specificity) but had a negative likelihood ratio of 0.7, indicating that it was not a reliable clinical test.

Conclusions:

Although the specificity of the UriSed analyzer was within acceptable limits, the sensitivity value was low. Thus, UriSed urinalysis results do not accurately predict the outcome of culture.  相似文献   

Inter-segmental coordination in progressions for the longswing on high bar     

Gareth Irwin 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):131-144

Abstract

The aim of this study was to determine if critical parameters for elite performance could be identified among a population of female shot putters. The performance of seven of the top women shot putters competing at the 2002 USA National Championships was examined. Video data were captured using two Panasonic 60 Hz cameras and the best throws of each athlete were digitized and analyzed using a Peak Motus three‐dimensional motion analysis system. Thirty variables were examined for their effect on the distance of the throw. Correlation analysis indicated that measured distance was positively correlated with release speed (r = 0.97, p < 0.0003) and shoulder‐hip separation (r = 0.72, p < 0.06) and negatively correlated with release angle (r = ‐0.74, p < 0.056), rear knee angle at rear foot touchdown (r = ‐0.93, p < 0.003) and rear knee angle at release (r = ‐0.76, p < 0.047). Greater knee flexion angle at both rear foot touch down and release along with a neutral shoulder‐hip angle at release were identified as the most critical parameters for success among this sample of elite women shot putters. The unique observation about the knee positions at specific events should assist in new training and coaching developments.  相似文献   

学业情绪及其研究进展     

邓瑾  符明弘  李雪皎 《潍坊教育学院学报》2012,25(6):68-70

学业情绪对学生的学习与成长有重要影响作用。近年来,国内外研究不仅对学业情绪的概念和维度有了明确的界定,并形成了一定的理论基础,同时还在学业情绪的特殊性以及对学业情绪的干预调节方面取得了新的进展,未来研究的方向主要集中在进一步深入探讨学业情绪与相关影响因素之间的关系以及积极探索适合不同学生群体的干预措施等方面。  相似文献