函数极值的充分条件的推广     

胡劲松 《绵阳师范学院学报》2007,26(2):35-37

推广函数极值的第二充分条件,讨论了f″(x0)=0时函数极值的判断,得到了一个判断函数图象的凹(凸)区间及拐点的方法。  相似文献   

论我国散手技术特色及其发展趋向     

马爱民 《安阳师范学院学报》2004,(2):113-115

通过对散手运动的考察,技术单一是阻碍该项目发展的重要因素,改进技术方法,突出竞技特色,进一步吸取中国传统武术技法技巧是完善和发展散手运动的有效途径,在此基础上的未来散手竞技无论从技术上、形式上一定会出现新的飞跃和提高.  相似文献   

高屈曲人工全膝关节表面置换术临床研究   总被引：1，自引：0，他引：1  

何森  曹文 《河北北方学院学报(医学版)》2007,24(3):20-22

目的:探讨应用高屈曲型假体行人工全膝关节置换术的早期临床效果。方法:2002.12~2006.3月间,对125例(213膝)患者用LPS-FLEX高屈曲型假体行TKA。其中男36例(62膝),女89例(151膝),年龄51~85岁,平均68.1岁。骨性关节炎90例(149膝),类风湿性关节炎35例(64膝)。所有病人均行常规髌骨置换,假体均采用骨水泥固定。结果:术后第一天即开始康复训练,伤口均一期愈合。随访12~52个月,平均34个月。2例因早期屈曲不佳(<90°)于术后6周在连续硬膜外麻醉下行手法松解后获得满意屈曲度,2例发生感染,其余均疗效优良。随访X线片结合临床均无感染、假体松动、假体周围骨折、骨吸收及脱位发生。HSS评分由术前30~65分,平均48分,提高至术后85~98分,平均91分。结论:LPS-FLEX高屈曲型假体在高屈曲位时仍在胫骨上保持面接触,且胫骨CAM始终在股骨SPINE的基部,从而在获得最大屈曲的同时保持了良好的稳定性。  相似文献   

云南省高校篮球队男性运动员膝关节损伤成因调查与对策研究     

洪锡钧  王世超 《大理师专学报》2013,(3):31-34

目的：为云南省高校篮球队的训练给予一定建议,为预防和减少损伤发生,保护运动员身体健康、延长运动寿命提供参考,在各种损伤成因的基础上提出独到的对策。方法：文献资料法、走访调查法、问卷调查法。结果：导致云南高校篮球队男性运动员损伤的因素主要是准备活动不合理、负荷不合理、带伤训练或比赛、身体冲撞、技术动作不过关、身体素质欠佳、机体疲劳、注意力不集中、自我保护意识差、医务监督不到位、场地设施不规格、营养不到位、运动装备差等。结论：加强学习,提高认识;科学合理训练,强调技术动作练习;合理膳食,营养到位,休息充足;加强完善运动场地设施建设。  相似文献   

Kinematic effects of repeated turns while running     

《European Journal of Sport Science》2013,13(8):1072-1081

Abstract

In team sports, non-contact ACL and MCL injuries occur during abrupt changes of direction, like turns or cutting manoeuvres. Fatigue affects dynamic neuromuscular control and increases knee injury risk. This study analysed how lower limb joints and centre-of-mass kinematics are affected throughout a high-intensity running protocol involving repeated 180°-turns. Twenty young men (18–23 years, BMI: 20.8–24.4?kg?m^?2) completed a 5-m shuttle running trial lasting 5?min at an average speed of 75% of their maximum aerobic speed. During the test, cardio-metabolic parameters were obtained, together with joints and centre-of-mass kinematics, using a motion capture system. Kinematic data were compared between the first and the last minute of exercise. Perceived exercise intensity ranged from “hard” to “maximum exertion” and post-exercise lactate concentration ranged from 5.4 to 15.5?mM. The repetition of 180°-turns induced a substantial reduction of hip (?60%, p?<?.001, large effect) and knee flexion (?40%, p?=?.003, medium-to-large effect), and an increase of hip adduction and internal rotation (+25–30%, p?<?.05, medium-to-large effect). Since such movements are factors increasing the likelihood of non-contact knee injuries, we concluded that the prolonged repetition of turns may expose participants to increased risk of ligament failure. Prevention programmes should include discipline-specific neuromuscular training especially in late practices.  相似文献   

对膝内侧副韧带损伤盘坐康复效果的观察     

陶胜国 《精武》2013,(35):7-8

观察盘坐对大学生运动员膝关节内佣副韧带损伤康复疗效。方法：将52例膝关节内例副韧带损伤大学生运动员随机分为两组。两组前期均采用针刺、推拿、TDP灯照射等方法进行治疗,待症状好转后,均进行15天的康复训练,实验组26例采用盘坐法康复,对照组26倒采用常规方法进行康复治疗。结果：实验组改良Lysholmscale评分积分值98．89,对照组分值86．42,差异有统计学意义（P〈0．01）。结论：盘坐较常规康复训练方法对膝关节内佣副韧带损伤彻底康复效果显著。  相似文献   

Isokinetic knee extension and vertical jumping: Are they related?     

Anna Iossifidou  Vasilios Baltzopoulos  Giannis Giakas 《Journal of sports sciences》2013,31(10):1121-1127

The aim of this study was to examine joint power generation during a concentric knee extension isokinetic test and a squat vertical jump. The isokinetic test joint power was calculated using four different methods. Five participants performed concentric knee extensions at 0.52, 1.57, 3.14 and 5.23 rad?·?s^?1 on a Lido isokinetic dynamometer. The squat vertical jump was performed on a Kistler force plate. Kinematic data from both tests were collected and analysed using an ELITE optoelectronic system. An inverse dynamics model was applied to measure knee joint moment in the vertical jump. Knee angular position data from the kinematic analysis in the isokinetic test were used to derive the actual knee angular velocity and acceleration, which, in turn, was used to correct the dynamometer moment for inertial effects. Power was measured as the product of angular velocity and moment at the knee joint in both tests. Significant differences (P <?0.05) were found between mean (?± s) peak knee joint power in the two tests (squat vertical jump: 2255?±?434W; isokinetic knee extension: 771?±?81W). Correlation analysis revealed that there is no relationship between the peak knee joint power during the vertical jump and the slow velocity isokinetic tests. Higher isokinetic velocity tests show better relationships with the vertical jump but only if the correct method for joint power calculation is used in the isokinetic test. These findings suggest that there are important differences in muscle activation and knee joint power development that must be taken into consideration when isokinetic tests are used to predict jumping performance.  相似文献   

Lower extremity joint coupling variability during gait in young adults with and without chronic ankle instability     

Thomas Lilley  Joseph Hart  Jay Hertel 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(2):261-272

Chronic ankle instability (CAI) is a condition resulting from a lateral ankle sprain. Shank-rearfoot joint-coupling variability differences have been found in CAI patients; however, joint-coupling variability (VCV) of the ankle and proximal joints has not been explored. Our purpose was to analyse VCV in adults with and without CAI during gait. Four joint-coupling pairs were analysed: knee sagittal-ankle sagittal, knee sagittal-ankle frontal, hip frontal-ankle sagittal and hip frontal-ankle frontal. Twenty-seven adults participated (CAI:n = 13, Control:n = 14). Lower extremity kinematics were collected during walking (4.83 km/h) and jogging (9.66 km/h). Vector-coding was used to assess the stride-to-stride variability of four coupling pairs. During walking, CAI patients exhibited higher VCV than healthy controls for knee sagittal-ankle frontal in latter parts of stance thru mid-swing. When jogging, CAI patients demonstrated lower VCV with specific differences occurring across various intervals of gait. The increased knee sagittal-ankle frontal VCV in CAI patients during walking may indicate an adaptation to deal with the previously identified decrease in variability in transverse plane shank and frontal plane rearfoot coupling during walking; while the decreased ankle-knee and ankle-hip VCV identified in CAI patients during jogging may represent a more rigid, less adaptable sensorimotor system ambulating at a faster speed.  相似文献   

中频电刺激对膝关节肌群等速肌力相关指标影响的实验研究     

张飞  刘一平 《吉林体育学院学报》2010,26(6):64-66

目的：探讨中频电刺激疗法对人体膝关节等速肌肉力量相关指标的影响。方法：将12名健康男青年随机分为对照组6人、中频电刺激干预组6人,干预组进行一个疗程中频电刺激。分别于实验前、后使用等速肌力测试仪测试受试者右侧膝关节肌群肌力相关指标,测试强度定为以下两组：角速度60°/s重复运动5次组和角速度180°/s重复运动15次组。结果：（1）与实验前相比,干预组角速度为60°/s时,膝关节屈、伸肌群相对平均峰力矩APT%BW显著升高（P〈0.05）,相对平均功率AP%BW明显增加（P〈0.01）;（2）干预组角速度为180°/s时,实验前后伸、屈肌群疲劳指数均FI减小且有统计学意义（P〈0.05）;（3）实验前、后干预组屈、伸肌群峰力矩角度变化均无显著性差异（P〉0.05）;（4）与实验前相比,对照组各项测试指标变化均无显著性差异。结论：中频电刺激疗法对提高人体膝关节肌群相对平均峰力矩、相对平均功率和降低疲劳指数有明显的效果,对提高膝关节肌群爆发力和耐力起到一定的作用。  相似文献   

优秀武术运动员指定动作训练损伤的调查分析   总被引：4，自引：0，他引：4  

黄杰聪  谭广忠 《体育科技》1999,(Z1)

采取填表和座谈两种方式对武术专业５３ 名优秀运动员指定动作训练损伤及其它损伤进行了调查,结果表明,武术运动员损伤以膝、踝关节、胫骨膜、腰肌、小腿肌内为主;动作难度大,身体素质要求高是指定性动作损伤的主要原因;落地支撑腿的膝、踝关节损伤、胫骨膜炎症等疲劳性疾病,与指定动作练习有关,局部负重过大、过度疲劳、身体素质不够等,是构成指定动作训练损伤的主要因素。  相似文献