动作协调与"爆发力"表现田径跳跃动作协调能力测量与评价方法研究

通过专家访谈与问卷调查,确定了6组12项动作指标作为协调能力测试行为样本。运用生物力学方法与人体运动的动力学方法,以相同动作冗余自由度的控制与不控制作为刺激变量,以动作爆发力表现水平的差值为因变量,通过对两组不同水平被试测验成绩的比较,对跳跃专项动作协调能力进行了定性与定量评价。     

跳远运动员助跑速度感知能力训练对踏板准确性影响的实验研究

通过问卷调查和实验法对跳远运动员助跑踏板准确性和影响跳远运动员助跑速度感知能力的主要因素进行理论与逻辑分析,根据跳远专项特点优选出9种训练方法,实验组采用优选训练手段,对照组采用常用普通训练手段。在严格控制训练过程及训练条件下,进行为期16周的速度感知能力的训练,保证两组只在训练内容方面不同外,其余方面保持一致。实验后对实验组和对照组再次进行踏板准确性和跳远成绩的测定,结果表明:实验后实验组与对照组的跳远成绩与踏板准确性具有明显的差异性。     

跳远助跑最后1O米分段速度的研究

本文根据鲍威尔、刘易斯等优秀跳远运动员助跑最后10米分段速度的变化，指出最后5米助跑速度比第一段5米助跑速度快，它与快速起跳结合的技术，是当今跳远训练的发展方向。     

The effects of attentional focus instructions on punching velocity and impact forces among trained combat athletes

Research indicates that instructing athlete’s to focus on bodily movements (internal focus of attention [IFA]) may hinder performance, whereas instructing them to focus on the movement outcome (external focus of attention [EFA]) often enhances performance. Despite the importance of instructions in striking combat sports, limited research has examined the influence of IFA and EFA on performance in well-trained combat athletes. This study investigated the effects of different instructional cues on punching velocity (m · s^?1) and normalised impact forces (N · kg^?1) among intermediate (n = 8) and expert (n = 7) competitive boxers and kickboxers. Athletes completed three rounds of 12 maximal effort punches delivered to a punching integrator on three separate days. Day one was a familiarisation session with only control instructions provided. In the following two days athletes randomly received IFA, EFA or control instructions prior to each of the three rounds. Athletes punching with EFA were 4% faster and 5% more forceful than IFA (P < 0.05), and 2% faster and 3% more forceful than control (P < 0.05). Furthermore, experts punched 11% faster and with 13% greater force compared with intermediate athletes (P < 0.05). EFA led to a positive effect on punching performance and should be favoured over IFA and control instructions.     

单源三站外辐射源雷达目标探测性能

论述全向外辐射源雷达空中目标探测系统的主要问题及系统体制损失。针对单源单站（SISO）和单源三站（SITO）两种工作方式,在接收天线阵元数相同的情况下分析探测距离和定位精度。在单源三站条件下推导直角坐标系中的目标速度矢量表达式,并分析速度测量精度。研究结果表明,在一定条件下,单源三站组网方式的空间覆盖范围与单源单站相当,且具有平面定位精度较高,可获得目标速度矢量和技术实现难度小的特点。     

Assessment of leg muscles mechanical capacities: Which jump,loading, and variable type provide the most reliable outcomes?

This study aimed to explore the strength of the force–velocity (F–V) relationship of lower limb muscles and the reliability of its parameters (maximum force [F₀], slope [a], maximum velocity [V₀], and maximum power [P₀]). Twenty-three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75?kg loads. The maximum and averaged values of F and V were obtained for the F–V relationship modelling. All F–V relationships were strong and linear independently whether observed from the averaged across the participants (r?≥?0.98) or individual data (r?=?0.94–0.98), while their parameters were generally highly reliable (F₀ [CV: 4.85%, ICC: 0.87], V₀ [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P₀ [CV: 3.5%, ICC: 0.93]). Both the strength of the F–V relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the F–V relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the F–V relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested.     

对我国青少年足球运动员伸、屈膝等动力量及下肢爆发力特点研究

通过文献资料法、测试法及数理统计法对国内不同年龄、等级青少年足球运动员大腿伸膝、屈膝肌群等动力量及下肢爆发力特点进行研究.结果表明,随年龄与训练年限的增长,青少年足球运动员伸、屈膝等动力量逐渐增加.18岁足球运动员屈膝等动力量明显高于16岁运动员,而在伸膝等动力量上两者没有明显差别.前者的伸膝/屈膝等动肌力比高于后者.在10 m站立式全速跑测试上,18岁足球运动员的成绩明显好于16岁足球运动员.然而在30 m站立全速跑及原地静止式纵跳、原地下蹲式纵跳的成绩上两者之间没有明显区别,说明下肢爆发力训练随年龄增长没有得到足够的重视.     

Power training in elite young soccer players: Effects of using loads above or below the optimum power zone

ABSTRACT

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.     

跳远起跳动作的计算机模拟

选取跳远起跳作为计算机模拟的动作对象,建立了内含颤摆质量的起跳力学模型,并在计算机上实施运动模拟。结果表明,研究所建立的起跳模型基本反映了人体在受到外界冲击时的缓冲特性,弥补了以往研究中采用力学碰撞理论来解决冲击问题所带来的不足之处。同时,也解决了以往研究不能完全得到地面约束反力或得到的地面力与真实情况相距较远的问题。     

后外点冰跳人体重心各参数的研究

对2003年北京中国杯世界花样滑冰大奖赛中国和世界一些优秀选手进行了跟踪定点三维测试,用国际先进的艾立尔系统和三维DLT方法对我国运动员高松和张民完成后外点冰跳动作进行了解析,比较分析了他们和完成同样跳跃动作的国外优秀选手的人体重心垂直方向位移-时间与速度-时间等相关参数。结论为落冰时支撑腿角度较小,重心偏低,虽有利于稳定但不利于重心速度的缓冲;落冰缓冲阶段冰刀侧向受力过大,使滑行不圆滑。