青少年男子铅球运动员施力特征探析     

张庆来  薛存波  葛超 《辽宁体育科技》2006,28(4):18-19

采用三维数字测力铅球仪对青少年运动员在整个投掷过程中的施力特征与动作技术特征进行分析,结果表明:(1)在完整推铅球动作过程中运动员对铅球的作用力曲线与铅球速度变化趋势基本一致,在最后用力动作过程中,合力曲线呈“双峰型”;(2)在最后用力开始左脚着地瞬间力值逐渐增大,到右腿蹬转使运动员身体由侧对投掷方向转为正对投掷方向瞬间出现第一次峰值;在推掷臂肘关节夹角约为90°时出现第二次峰值。  相似文献   

BIODEX在大腿、膝关节伤后功能诊断及康复中的应用   总被引：1，自引：0，他引：1  

杨静宜  赖柳明 《北京体育大学学报》1993,(2)

42名有大腿前、后群肌肉拉伤或膝关节急、慢性损伤史的运动员为受试者。用BIODEX 多关节等速测力及康复系统测定膝关节屈、伸肌群肌力,取60(°)/s 向心、离心及240(°)/s 向心收缩的最大力矩(PT)等指标,用“评价表格”进行分析评定,并对力矩曲线加以分析。初步认为,力矩曲线异常具有功能诊断参考价值,并可用于选拔运动员时及时发现伤情。参照BIODEX 测试结果,有针对性的进行康复锻炼,可收到良好效果。  相似文献   

利用特例解几何题的技巧     

刘向臣  李艳青 《唐山师范学院学报》2001,23(5):50-51

以具体实例说明解题过程中如何巧妙灵活地取特殊值、特殊点、特殊曲线、特殊图形的方法和技巧。  相似文献   

非计算法绘制酸碱滴定曲线     

高小茵 《玉溪师范学院学报》2001,17(Z1):255-257

本文提出了一种简单快速绘制酸碱滴定曲线的方法.该方法不需要进行繁杂的pH值计算,只需知道弱酸或弱碱的离解常数就可很快绘制出酸碱滴定曲线.  相似文献   

肿瘤学研究论文中的生存曲线图谬误辨析     

庄爱华  甘可建  柳青  钱朝南 《编辑学报》2008,20(6):491-492

对肿瘤学期刊已发表的论文或稿件中绘制生存曲线所存在的问题进行实例分析,以期为编辑人员加工文稿时提供参考.  相似文献   

关于具有两个二次代数曲线解的三次系统的极限环     

Zhang Cheng 《大连大学学报》1995,(4)

本文介绍近年来在这方面研究的进展情况,同时给出一些新的结果,并提出一些尚未解决的问题。  相似文献   

Reciprocal Versus Nonreciprocal Assessment of Knee Flexors and Extensors in Concentric Actions Using the CON-TREX Multijoint Isokinetic Dynamometer: A Reliability Study     

Alex Bliss  Jeanne Dekerle 《Measurement in physical education and exercise science》2019,23(2):118-123

Knee flexor and extensor muscular assessment via isokinetic dynamometry is common practice and established in the research literature. However, reporting assessment methodology regarding reciprocal and nonreciprocal movements is often vague or absent. Such methodological issues are crucial for accurate assessments. Therefore, knee extensor and flexor peak moment using either reciprocal movement or nonreciprocal modalities was assessed. Fifteen participants performed three blocks of five concentric muscle actions at three angular velocities [1: nonreciprocal (maximal active flexion followed by passive extension); B2: reciprocal (maximal active extension followed by maximal active flexion); B3 nonreciprocal (maximal active extension followed by passive flexion)]. ANOVA revealed statistically significant within-subject modality effects for peak knee extensor moment and flexor velocity and modality differences (p < .05). Reciprocal and nonreciprocal assessments give significantly different results, with nonreciprocal giving higher peak moments. Reporting which modality is used is crucial to allow for greater clarity for the reader and practitioner.  相似文献   

基于HHD测试的男子羽毛球运动员肩关节旋转特征分析     

王聪  秦学林 《福建体育科技》2017,36(1)

目的:通过观察男子羽毛球运动员肩关节旋转活动度及肌力的特征,为羽毛球运动员肩关节损伤的预防和康复提供参考。方法:以16名专业羽毛球男子运动员为受试对象,同时以9名普通男子为对照,使用手持式测力计(HHD)测定优势侧及非优势侧肩关节的旋内、旋外肌力;同时,测量其旋转被动活动度。结果:(1)男子羽毛球运动员肩关节旋外被动活动度大于旋内被动活动度。(2)男子羽毛球运动员肩关节优势侧旋内、旋外肌力均大于非优势侧,但旋外/旋内比例不存在双侧差异。结论:(1)男子羽毛球运动员肩关节旋转活动度存在双侧差异。(2)男子羽毛球运动员优势侧肩关节旋内、旋外肌力均大于非优势侧。  相似文献   

Guiding Low Spatial Ability Individuals through Visual Cueing: The Dual Importance of Where and When to Look     

Victoria A. Roach  Graham M. Fraser  James H. Kryklywy  Derek G.V. Mitchell  Timothy D. Wilson 《Anatomical sciences education》2019,12(1):32-42

Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low-performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye-movement patterns of high-performing individuals, collected via eye-tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability “where” to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists.  相似文献   

平面Bézier曲线细分算法的参数优化     

马晓辉  林凤鸣  申立勇 《中国科学院大学学报》2016,33(3):311-316

复杂曲线逼近是CAGD中的基本问题,传统deCasteljau算法通常固定细分参数为0.5.本文考虑平面Bézier曲线的凸包最小和扁平度最小两种情况,分别给出凸包最优和扁平度最优的细分参数的定义和计算方法,使每次细分后得到的新控制多边形更好地逼近原曲线.通过分析不同类型曲线的最优参数发现,对于较小的曲线段,细分参数选为0.5具有一定的合理性.比较扁平最小方法与deCasteljau定参数方法发现:对于形状复杂的曲线,前者细分效率提高50%以上;对于简单曲线,二者相当.  相似文献