对我国优秀女子标枪运动员最后用力过程中左腿技术的研究

对我国优秀女子标枪运动员最后用力过程中左腿的动作技术进行了定量研究。结果表明：交叉步右脚着地后，左膝水平速度与重心水平速度显著相关（γ＝０．７３０２，Ｐ＜０．０１），加速左腿的前摆有助于重心水平速度的回升；影响标枪出手速度的灰色关联排序中首要因素是标枪离手时左膝角，说明左腿迅速而充分的蹬伸对出手速度起着重要的影响作用。     

李春秀、高红苗竞走技术对比分析

在比赛现场采用高速摄影拍摄，对技术图片进行直接测量和解析，依据国际田联比赛规则中竞走定义的技术标准，对我国优秀运动员李春秀、高红苗的竞走技术进行对比分析研究，并指出其技术优缺点。目的在于提高我国女子竞走技术，在１９９５年北京举行的竞走世界杯赛上，避免技术犯规，夺取金牌。     

“立法正确”的神话之破解

“立法正确”的神话诞生于近代西方工业化的扩展和民族国家的形成,以“新国家学说”所主张的形式与内容相分离为理论基础。首先,它主张立法形式的正确性,要么将立法内容交由权力决定,使“恶法亦法”成为题中应有之义;要么认为内容出自形式,这纵然令人向往,但终究是个“神”的问题。其次,它假定立法内容的正确性,立法者不颁布“卑鄙的”法律,德国民族社会主义的立法实践,使这一假定成为彻底破灭的神话。“立法正确”的基本神话,可推出另外两个神话：（1）禁止法官造法和准确把握立法原意;（2）启蒙百姓懂法。同样,这两个神话也是永远不能实现的。文章还探讨了“立法正确”的神话破灭后之可能出路：一是人民的反抗权难题;二是法官如何以理释法。     

CIP-I智能人工腿步速控制系统硬件设计

CIP-I Leg是国内首个智能仿生人工腿原型机。针对智能仿生人工腿应能模仿人体健康腿的运动方式且步行速度可自然、随意地跟随截肢者步行速度的变化而变化的重要特点,同时考虑到高精度、低功耗和抗干扰能力强等,设计了一种基于新型超低功耗微处理器MSP430F149的人工腿步速控制系统硬件电路。实验结果表明,所设计的步速控制系统运行可靠、功耗低、精度高,可有效地用于自行设计的CIP-I Leg的控制。     

我国优秀男子跳高运动员起跳力量特征研究

运用运动生物力学测试的方法，对我国优秀男子跳高运动员起跳力量特征进行了研究。结果表明：起跳腿踏跳过程中所受的垂直冲击力可达本人体重的5．77-7．24倍，踏跳时间为0．150～0．172s；起跳腿肌肉反应特性值为35、72～43．61，并且与起跳过程中垂直速度变化值呈高度正相关；起跳过程中膝关节和髋关节肌肉的退让收缩力量水平均对成绩有着很大的影响；与国外优秀运动员相比，我国运动员的起跳力量较弱，部分运动员的起跳技术存在不足。     

Active recovery effects by previously inactive muscles on 40-s exhaustive cycling

Abstract

The effects of active recovery using previously active and inactive muscle groups on power output and respiratory responses were examined. Ten male volunteers underwent two exhaustive 40-s bouts of leg cycling (1st Ex and 2nd Ex), separated by a 20-min recovery period. The recovery conditions were leg (Leg-Active) or arm (Arm-Active) cranking at 50% ventilatory threshold (VT), or sedentary control (Passive). The total output work (Total work) during the 2nd Ex in the Leg-Active condition was significantly higher than that in the Passive (299 vs. 282 J · kg body mass^?1 (J · BM^?1)). The values of Total work, peak [Vdot]O₂ and peak heart rate during the 2nd Ex were significantly higher than those during the 1st Ex in both Leg- and Arm-Active. Total CO₂excess after the 1st Ex was significantly higher than that after the 2nd Ex (67.6 vs. 26.0 ml · BM^?1) in Passive. After the 2nd Ex, the Total CO₂excess in the Leg-Active (51.5 ml · BM^?1) was significantly higher than that in both the Passive (26.0) and Arm-Active (36.5), with Arm-Active being significantly higher than Passive. The recovery exercise using previously inactive muscles improved respiratory compensation ability related to performance enhancement.     

Kinematics of side and cross circles on pommel horse

Abstract

One of the most fundamental skills on the pommel horse is double leg circles (circles). Circles can be performed on all parts of the pommel horse. It was hypothesized that the different sets of physical constraints of the apparatus require a gymnast to adapt circles technique. The purpose of this study was to quantify how gymnasts modify their technique during circles to accommodate different physical obstacles due to different support surfaces and body orientations. To investigate these adaptations, a comparison of the two most common circles on pommel horse – namely, circles in cross support (cross-circles) and circles in side support (side-circles) – was carried out. Seven elite male gymnasts performed three sets of 10 cross-circles and side-circles on a pommel horse. Three-dimensional coordinates were acquired using 12 Qualisys ProReflex motion tracking cameras operating at 120 Hz. Temporal characteristics, the motion of the centre of mass, and the body angles – flexion and lateral flexion – were analysed. We found that cross-circles took less time to complete a single circle (0.92±0.02 vs. 0.95±0.02 s), had a smaller ratio for the rear support phase (0.15±0.02 vs. 0.18±0.03), a narrower supporting-hand distance (0.33±0.03 vs. 0.52±0.00 m), greater flexion of the body over the rear support phase (44±12° vs. 27±8°), and less lateral flexion of the body over the single-hand support phase (entry: 20±5° vs. 35±3°; exit: 26±4° vs. 33±4°) than side-circles. Our results suggest that gymnasts adapt their technique to the physical constraints imposed by the shape of the pommel horse and the location and orientation of the circles. Cross-circles were characterized by a high rear support position with a narrower hand-spacing, which would require excellent shoulder flexibility and strength. Consequently, lack of these traits may explain the need for greater body flexion in cross-circles than in side-circles during rear support. Understanding the technical differences will facilitate an effective transfer of the technical similarities among different types of circles.     

Isokinetic Leg Flexion and Extension Strength of Elite Adolescent Female Track and Field Athletes

Abstract

Sixty-two elite adolescent (age: 16.39 ± 1.62 yrs) female track and field athletes volunteered to be measured isokinetically for peak torque of the leg flexors and extensors. The sample included 16 throwers, 11 jumpers, 12 middle-distance runners (> 400 m), and 23 sprinters. A Cybex II isokinetic dynamometer was used to measure dominant leg strength at 180°/sec. One-way ANOVA revealed significant between group differences for absolute flexion and extension (Nm), extension/body weight (Nm/Kg), and extension/lean body weight (Nm/Kg). Scheffe post-hoc comparisons showed that, for absolute leg extension strength, throwers were stronger than middle-distance runners (by 54.4%), sprinters (35.6%), and jumpers (23.6%). For absolute leg flexion movements, throwers were stronger than middle distance runners (37.4%) and sprinters (32.1%). Jumpers had greater extension peak torque values than middle-distance runners relative to body weight (14.0%), and throwers were stronger than middle-distance runners for extension/lean body weight (14.9%)). No other comparisons were significant. However, when strength was expressed relative to body weight or lean body weight, there were few differences between events for flexion or extension. Given that absolute strength scores were correlated with body weight and lean body weight, peak torque/body weight or peak torque/lean body weight may be more sensitive than absolute values as indicators of underlying factors (such as training status or fiber type composition) responsible for the differences in muscular strength between groups.     

跳远起跳时摆动腿加速前摆的时机

对跳远运动员所产生的一些错误起跳动作进行了理论分析,认为起跳时摆动腿加速前摆时机的差异,是诱发错误起跳动作的主要因素。在起跳过程中,只有正确掌握摆动腿加速前摆的时机,才能在短促的起跳时间内充分发挥出最大的蹬伸力量,获得良好的起跳效果。     

跳高运动员起跳腿“超等长”收缩能力的生物力学研究

采用运动学和动力学同步实验等研究方法,对30名男子跳高运动员的"超等长"收缩能力进行生物力学研究,针对影响跳高运动员起跳效果的退让性工作能力、蹬伸能力进行不同级别运动员的对比分析,为跳高运动员的专项力量训练提供理论依据.